International Journal of Vehicle Design (84 papers in press)

Regular Issues

• Refined modelling of thin-walled beam, plate and joint for automobile frame  
  by Jiantao Bai, Wenjie Zuo 
  Abstract: At the conceptual design stage, the simplified frame is extensively applied in the body-in-white (BIW) structure to rapidly calculate its performances. However, it is difficult to acquire an accurate simplified frame of the BIW structure for the calculation of the bending stiffness, torsional stiffness and frequencies. This paper proposes a simplified modelling method by using the thin-walled beams (TWBs) with complex sections, semi-rigid elements and cross beam structures to create the simplified frame. Compared with the traditional modelling method, the TWBs contain more types of the complex section, the semi-rigid elements can describe various deformations, and the plate structures are further considered. Firstly, the properties of the complex sections are summarised. Especially, the torsional moments of inertia of the multi-cell sections are derived. Secondly, the semi-rigid beam element is reduced to a super element, which is composed of one beam element and three translational and three rotational springs. Among them, the spring stiffness of the semi-rigid element is obtained by solving the detailed finite element model of the TWBs, which can be accurately and rapidly solved by using this method. Thirdly, the cross beam structure is introduced to replace the plate structure by the equivalence of the mass and central deflection for the first time. This method can further improve the accuracy of the simplified frame. Lastly, a numerical example demonstrates that the simplified frame can accelerate the conceptual design of the BIW structure.
  Keywords: conceptual design; frame structure; complex section; semi-rigid element; cross beam structure.
  
  
• A novel design of a dry clutch pressure plate for weight reduction without compromising its thermo-mechanical performance  
  by Tolga Cakmak, Muhsin Kilic 
  Abstract: The main objective of this study is to conduct experimental research to investigate the effect of ventilation channels that have never been incorporated into the conventional automotive clutch pressure plate. The purpose is to reduce its weight without compromising its thermo-mechanical performance. Both convective and conductive heat transfers of the clutch pressure plate have been enhanced in order to meet thermo-mechanical performance requirements, by ventilation channels and by chemical composition adjustment, respectively. The novel design of ventilated
  Keywords: dry clutch; heat transfer enhancement; weight reduction.
  DOI: 10.1504/IJVD.2022.10052384
   
  
• Dual-redundancy multi-mode control of high safety reliability steering wheel system  
  by Junnan Mi, Tong Wang, Xiaomin Lian 
  Abstract: The steering wheel system of a steer-by-wire system (SBW) offers steering torque to driver. In order to improve its safety and reliability, a dual-redundancy steering wheel system is proposed. This research proposes a dual-redundancy multi-mode control method for this system, which is divided into different control modes, namely the angle alignment mode, the pivot steer with resistance mode, and the uniform approach to middle position mode, so that the system can adapt to different vehicle running states and drivers manipulation habits. At the same time, a torque balance control method for two channel motors is proposed to balance their torques, and an order-reduce and reforming control method is proposed so that the system can still work even if one motor fails. Finally, this study built a vehicle test platform to verify the control method and prove its effectiveness.
  Keywords: steer-by-wire; safety; steering wheel; redundancy; control; steering torque ;SBW.
  
  
• Damage equivalent virtual tracks for motorcycles  
  by Aptin Haerian, Kemal Öztürk, Robert Liebich 
  Abstract: The present work deals with the topic of service loads for motorcycles resulting from road excitation. The aim is to create virtual test tracks that can be used representatively for load assumptions. First, different methods from the field of durability engineering are reviewed that centre around the topic of damage equivalency. The methods are evaluated in terms of applicability for virtual test tracks. With an omission approach, a novel method was found to detect relevant track segments for different use cases. The method was successfully applied to create virtual test tracks based on measurements of real tracks with laser scanners. With the proposed method the length of the test tracks and data amount could be decreased by approximately 70%. The gained perceptions enable a faster definition of design loads while additionally saving costs and reducing the amount of data during the early stages of development.
  Keywords: virtual proving ground; multi-body simulation; motorcycle; durability; damage equivalency; omission approach.
  
  
• Nonlinear vehicle active suspension system control method based on the extended high gain observer  
  by Qinghua Meng, Bingji Li, Chuan Hu 
  Abstract: In order to reduce the number of sensors used in the vehicle active suspension system and improve the ride comfort and handling stability, this paper proposes a novel vehicle active suspension control approach based on an extended high gain observer approach. Firstly, for facilitating the controller design, the underactuated active suspension dynamic model is transferred to a fully-actuated system dynamic model. Then the extended high gain observer (EHGO) is constructed to estimate the unknown states and uncertainties according to the state functions of the active suspension control system. An output feedback controller based on EHGO is designed to improve the vertical ride comfort and handling stability of the active suspension. Furthermore, the closed-loop system is analysed to prove the boundedness of all the states. The EHGO approach is proved to stabilise the active suspension by Lyapunov stability analysis. Simulation and experiment results verify the effectiveness of the designed controller.
  Keywords: active suspension; extended high gain observer; underactuated system; Lyapunov stability analysis; nonlinear control.
  
  
• Estimation method of vehicle sideslip angle considering coupled longitudinal and lateral dynamics  
  by Qian Zhang, Hongliang Zhou, Zhiyuang Liu, Linhui Zhao 
  Abstract: The coupled longitudinal and lateral dynamics control plays an important role in improving the vehicle motion performance. It is very complex to describe the lateral tyre force with a coupled longitudinal and lateral dynamics, thus making it difficult to establish a lateral dynamics model and design a sideslip angle observer. In this paper, based on the piecewise affine (PWA) description of the lateral force, a novel lateral dynamics modelling method is proposed considering coupled longitudinal dynamics. Firstly, a nominal PWA model of the lateral force is established. Secondly, by regarding the slip ratio and the dynamic load as varying parameters, we obtain a novel PWA lateral dynamics model which can describe the influence of the slip ratio on the lateral dynamics. Finally, the switched T-S observer is presented. Simulation results show the effectiveness of the proposed PWA model and the designed observer.
  Keywords: coupled longitudinal and lateral dynamics; piecewise affine model; vehicle sideslip angle; lateral force; slip ratio; switched T-S observer.
  
  
• Automotive airbag stiffness evaluation: a simulation-based conceptual design  
  by Javad Marzbanrad, Vahid Rastegar, Esmail Dehghani 
  Abstract: In this research, a model and a particle simulation method were used to analyse the stiffness of a fully deployed airbag that is related to the severity of the occupant injury in a frontal crash. First, a mathematical model based on a three-dimensional airbag geometry was introduced. Then, quasi-static and dynamic test setups were defined, including an external impactor to simulate an actual crash. A simulation was also designed by the corpuscular method with the same initial conditions to validate the airbag model and to assess the effect of parameters at the out-of-position impact. Finally, airbag stiffness characteristics were calculated for different airbag capacities and inflator performances as a function of internal pressure and volume. The evaluated time-dependent stiffness characteristics were linearized by the proposed method. The estimated coefficients were correlated to airbag geometry and inflator performance and can predict occupant injury in a high-speed crash.
  Keywords: automotive airbag; in position; out of position; stiffness; linearization; corpuscular method; conceptual design; occupant safety; crash injury; inflator performance.
  
  
• Optimisation design and performance evaluation of a novel dual-motor multi-mode coupling powertrain for electric vehicles  
  by Wei Du, Shengdun Zhao, Jingzhou Gao 
  Abstract: With a certain battery capacity, the mileage of an electric vehicle depends on the efficiency of the powertrain. In this paper, a novel dual-motor multi-mode coupling powertrain (DMMCP) is proposed. This paper compares it with the traditional powertrain composed of a single-motor and two-speed transmission (SMTSP). To make a fair comparison, the influence of component parameters on the powertrain must be considered. So this paper proposes a method that can evaluate the dynamic or economic performance at the same time as the parameter optimisation. Then the dynamic performance and economy of the two powertrains are evaluated. The results show that the dynamic performance and economy of DMMCP are better than SMTSP, so DMMCP has enormous development potential.
  Keywords: dual-motor multi-mode coupling powertrain; electric vehicles; dynamic programming; NSGA_II.
  
  
• Effect of inflation pressure on tire forces under combined-slip conditions based on the UniTire model  
  by Xiaoyu Li, Nan Xu, Konghui Guo, Chao Yang, Yanjun Huang 
  Abstract: The UniTire model is a nonlinear semi-empirical tyre model for the dynamic simulation and control of a vehicle under complex wheel motion inputs involving pure longitudinal/lateral slip and combined slip. Based on the model, this study reveals how the inflation pressure affects the tyre forces under combined-slip conditions and then integrates such effects into the UniTire model to extend its applicability. First, by introducing a direction factor for the resultant shear force, the UniTire model for combined-slip conditions is developed to represent the tyre forces. Second, this paper comprehensively studies the effect of the pressure on the direction factor and tyre normalised properties to uncover the intrinsic correlation between the pressure and tyre forces. The experimental data are used during the entire analysis, and the results show that the anisotropy of tyre stiffness is a key factor for determining the resultant force direction under combined-slip conditions. More importantly, the UniTire model can be extended or complemented by incorporating the effect of the inflation pressure such that the model can be effectively applied in broader working conditions.
  Keywords: UniTire model; combined-slip forces; tyre anisotropic stiffness; inflation pressure variation.
  
  
• Design and evaluation of a driver intent based mobile control interface for ground vehicles  
  by Chengshi Wang, Kim Alexander, Philip Pidgeon, John Wagner 
  Abstract: The advent of drive-by-wire technologies has enabled exceptional mobility options for a greater number of drivers (e.g., age, experience, physical limitations). To extend the capability of current advanced drive-by-wire vehicles, an alternative vehicle driving mechanism must be considered to accomplish different driving manoeuvres while adapting to specific needs and constraints of certain drivers. In this study, a cellphone-inspired portable human-machine-interface (HMI) that incorporated the directional control of the vehicle as well as the brake and throttle functionality into a single holistic device is presented. A nonlinear adaptive control technique and an optimal control approach based on driver intent are also proposed to accompany the mechatronic system for combined longitudinal and lateral vehicle guidance. Assisting the disabled drivers by excluding extensive arm and leg movements ergonomically, the device has been tested in a driving simulator platform. Human test subjects evaluated the mechatronic system with various control configurations through obstacle avoidance and city road driving test, and a conventional set of steering wheel and pedals were also used for comparison. Subjective and objective results from the tests demonstrate that the mobile driving interface with the proposed control scheme can enhance the drivers performance by up to 55.8% when compared with the traditional driving system during aggressive manoeuvres. The systems superior performance during certain vehicle manoeuvres and approval received from the participants implies its potential as an alternative driving adaptation for disabled drivers.
  Keywords: longitudinal and lateral dynamics; vehicle dynamics; nonlinear control; adaptive control; optimal control; state flow control; mobile control interface; portable HMI; emulated cellphone driving device; driver intent; human subject testing; ground vehicles; drive-by-wire.
  
  
• Charge equalisation of electric vehicle battery system using intelligent controller  
  by Ginu Ann George, Mary Chacko Fossy, A. Prince, M.V. Jayan, Sunil P.R. Kumar 
  Abstract: Emissions from conventional vehicles adversely affect the environmental balance, thereby an enhanced adaptation of electric vehicles (EVs) is required. Among the existing energy storage systems, rechargeable batteries, especially Li-ion batteries, play a major role in the commercialisation of EVs owing to their long cycle life, high energy and power density and low self-discharge. A novel state of charge (SOC) based modular cell balancing equaliser (CBE) scheme integrated with intelligent control techniques is proposed. The performance of CBE is analysed, based on the simulation works done under a Simulink MATLAB environment with series-connected modular Li-ion battery. The bidirectional non-dissipative CBE structure cooperating with an intelligent controller balances the voltage among the cells considering the effect of the SOC of individual cells. The proposed balancing circuit and control method improves the speed of balancing and the accuracy without exceeding the upper voltage limit, as evident from the simulation results.
  Keywords: electric vehicle; hybrid electric vehicle; energy storage system; lithium-ion battery; battery management system; cell-balancing equaliser; state of charge; fuzzy intelligent controller.
  DOI: 10.1504/IJVD.2022.10050920
   
  
• Structure design and anti-slip control system of magnetorheological limited slip differential  
  by Peng Zhao, Wanli Song, Zhongyang Diao, Menghao Liu, Na Wang 
  Abstract: This paper presents a novel design scheme of magnetorheological limited slip differential and analyses its structure and principle. Compared with the ordinary differential, the proposed magnetorheological limited slip differential overcomes the disadvantage of 'same torque but different speed' of the common differential. The finite element analysis is used to analyse and optimise the damping model. The anti-slip control system of the vehicle model is established based on the fuzzy PID method, and the performance of magnetorheological limited slip differential is studied by using simulation software to simulate the vehicles movement in typical road conditions. The simulation results show that the new magnetorheological limited slip differential proposed in this paper can redistribute the driving torque of the left and right driving wheels reasonably when the vehicle is skidding, so that the vehicle can overcome skidding and improve the stability of the vehicle.
  Keywords: structure design; magnetorheological limited slip differential; finite element analysis; anti-slip control system; driving torque.
  
  
• Rollover stability and anti-roll control of sport utility vehicle with driver in the loop  
  by Zhilin Jin, Zhenghua Yan, Wanzhong Zhao 
  Abstract: Rollovers are a type of fatal traffic accident for ground vehicles. Most rollover accidents, however, can be avoided through proper driver actions. In order to explore the effect of the drivers actions, the rollover stability of a sport utility vehicle (SUV) with a driver in the loop is analysed, and an anti-roll control strategy is proposed to prevent the vehicle rolling over when drivers cannot take proper emergency measures. To obtain the drivers reaction to vehicle rollover, the linear quadratic regulator method is applied to the drivers decision-making model. The laws of rollover stability and the corresponding influence of the parameters of the driver are illustrated. Then, a rollover prevention strategy using sliding mode control and an electronic hydraulic braking system is put forward to help the driver to control the vehicle. Furthermore, numerical simulations are presented for a SUV in tripped and untripped rollover conditions. The results show that experienced and physically fit drivers can manipulate the steering wheel accurately and timely to prevent vehicle rollover under emergency conditions. The proposed control method is helpful to improve roll stability and reduce vehicle rollover.
  Keywords: rollover stability; driver in the loop; anti-roll control; electro hydraulic brake.
  
  
• Analysis of consumer preferences regarding automated driving technology and driving environment: the case of South Korea  
  by Seungryong Jeon, Kyuho Maeng, Youngsang Cho 
  Abstract: This study analysed consumers preferences regarding the technological attributes of automated vehicle (AV) and the driving environment. We conducted a conjoint survey among 1008 respondents in Korea. Based on the collected data, a utility function was estimated using a mixed logit model, considering the heterogeneity of the respondents preferences. In the conjoint survey design, we considered six core technological and economic attributes of automated driving: road conditions, weather conditions, ambient lighting conditions, fuel efficiency, automated driving level, and price. The empirical results show high heterogeneity in consumers attitudes towards AV technologies. By comparing the relative importance of these six attributes, we found that the price of the automated driving option is the most important attribute, followed by road conditions. Furthermore, the predicted market share of AVs, considering their technological evolution, shows that affordable price is an important factor for their diffusion.
  Keywords: automated vehicles; consumer preference; conjoint analysis; mixed logit; willingness to pay.
  
  
• Optimal design and experimental research on a new hybrid electromagnetic actuator with energy reduction for vehicle suspension systems  
  by Renkai Ding, Ruochen Wang, Xiangpeng Meng, Long Chen 
  Abstract: The linear electromagnetic actuator (LEMA) fails to balance the energy regeneration/electric energy reduction and dynamic performance of suspension systems. A new hybrid electromagnetic actuator (HEMA) integrating a linear motor and a hydraulic damper is put forward and designed to address the problem in this study. On the basis of the preliminary determination of the design and constraints of the HEMA, a modified skyhook control is employed as the control method, and the performance parameters are optimised for different road conditions. The urban road condition is used as an example, the performance requirement that should be achieved in this driving condition is considered as the optimisation goal of the structural parameters, and the theoretically achievable performance of HEMA is obtained. Then, a prototype is developed for characteristic and dynamic control tests. Results show that the HEMA can ensure the dynamic performances while recovering vibration energy compared with the LEMA. In the active control process, the former can significantly reduce the electric energy consumption and achieve the same dynamic performance control. Moreover, the HEMA can significantly improve riding comfort while keeping the dynamic tyre load within a reasonable range. The results demonstrate that the HEMA can effectively coordinate the vibration energy regeneration/electric energy reduction and dynamic performance of suspension systems.
  Keywords: HEMA; vibration energy regeneration/electric energy reduction; dynamic performance; optimal design; experimental research.
  
  
• Experimental verification of the new methodology for assessment of the relative adhesion  
  by Milan Klapka, Ivan Maz?rek, Petr Novák 
  Abstract: The vehicle suspension in good technical condition is essential for safe driving. This article deals with experimental verification of new assessment methods for the resonance adhesion testing of the car suspension. Results of tests of more than 400 unique passenger cars assessed according to established EUSAMA methodology are compared with the results obtained by a suggested new methodology called standardised adhesion (STA). Additionally, the effect of excitation stroke amplitude is analysed experimentally on the assessed relative adhesion. The established EUSAMA methodology rather examines suspension in terms of handling the car under prescribed test conditions; however, the required testing conditions are outdated for current designs of suspension. The suggested STA methodology examines only a real condition of suspension damping under standardised testing conditions, which is its main advantage. The obtained results proved that the suggested STA methodology could be either a supplement or complete replacement of the established methodology for assessment of the suspension technical condition according to EUSAMA prescription which is not completely reliable currently.
  Keywords: relative adhesion; suspension; shock absorber; EUSAMA; technical diagnostics.
  
  
• Research on situation cognition approach of an unmanned surface vehicle under complex ocean conditions  
  by Lili Yin, Rubo Zhang, Hengwen Gu, Ning Guan 
  Abstract: This research project is conducted under the background of complex tasks of an unmanned surface vehicle in a complex ocean environment, to solve some problems such as assisting cognition for users, assessing the operation of users using situation cognitive results, and supporting the decision. The system framework of the situation cognitive approach is proposed in the paper, which includes environmental event recognition, influence degree of uncertain events calculation, executive capability assessment, task recommendation and comprehensive situation cognition. The cognitive approach for uncertain environment based on the combination of fuzzy logic and Bayesian network is proposed to achieve the cognitive process. The results of the situation cognitive method were used to update the situation ontology mode featuring probabilistic extension. In this way, the situation cognitive method for an AUV in an uncertain ocean environment extended the ability of uncertainty presentation and reasoning in ontology. The approach was validated by marine experiments and simulating experiments for the unmanned surface vehicle. Results show the effectiveness of situation cognitive approach.
  Keywords: unmanned surface vehicle; complex ocean conditions; situation cognition; ontology model; marine experiments.
  
  
• Research on intervention criterion and stability coordinated control of AFS and DYC  
  by Xiaojian Wu, Bing Zhou, Tingyang Wu, Qianxi Pan 
  Abstract: Aiming at improving vehicle handling stability, an intervention criterion and a coordinated control method for active front steering (AFS) and direct yaw moment control (DYC) are proposed in this paper. First, by analysing the characteristics of the linear, nonlinear and saturation regions of the lateral tyre force, the intervention criterion of AFS/DYC stability control based on the working state of lateral tyre force is proposed. Next, a 7-DOF (degree-of-freedom) dynamics model is established, and a method for identifying nonlinear pure lateral force model based on the onboard sensors and the vehicle handling stability experiment is developed. According to the identified tyre model, the mapping relationship between the lateral tyre force saturation point and wheel angle is constructed, which forms the rapid judgment method of the working state of the lateral tyre force, together with the approach of judging the linear/nonlinear state through the wheel angle. Then, a UKF-based state observer is designed to provide real-time information for the control system. The ideal reference, the upper level control algorithm of superimposed yaw rate, the lower level control algorithm, and the AFS/DYC yaw moment distribution coefficient reflecting the working state of the lateral tyre force are designed for the proposed AFS/DYC control system. Finally, a fishhook test and a step input test are carried out on low adhesion coefficient roads, which verifies that the proposed AFS/DYC coordinated control system can effectively improve vehicle handling and stability.
  Keywords: vehicle handling stability control; active front steering; direct yaw moment control; intervention criterion; coordinated control; state observation.
  
  
• A theoretical and experimental study on a vehicle with exhaust heat recovery  
  by Zhu Liang, Wang Shuangfeng, Chen Kai, Zeng Zhixin 
  Abstract: The performance of the Exhaust Heat Recovery System (EHRS) is analysed. First, an integrated vehicle model with the cabin heating system is established. A vehicle test is conducted to verify the simulation model and to assess the performance of original system. Using the simulation model, the interaction between the EHRS, cooling system, cabin heating system and exhaust system is studied. Then the cooling system is improved aiming to reduce the fuel consumption and improve the system performance. The numerical results show that increasing the pump speed ratio can significantly improve the performance of low-temperature heating, and has little effect on fuel consumption. Adjusting the cooling circuit of the EHRS can effectively reduce fuel consumption and improve heating performance.
  Keywords: integrated vehicle system model; exhaust heat recovery; cooling system; cabin heating system; exhaust system.
  
  
• Study on reducing cogging torque and core loss of in-wheel motor for electric vehicle based on stator full-slot offset  
  by Qiping Chen, Xuanjun Huang, Hao Shao, Hui Chen, Chagen Luo 
  Abstract: In order to reduce cogging torque and core loss of in-wheel motor for electric vehicle, the paper proposes a full-slot offset method to analyse the above problems. Firstly, the calculation formulas of cogging torque and the core loss are deduced, the parameters of the in-wheel motor are determined, and the geometric model of the in-wheel motor is established. Secondly, the models with different offset angles are imported into the finite element simulation model, the cogging torque and core loss are calculated respectively, and the correctness of the model is verified. The simulation results show that the full-slot offset angle is 3 degrees, and the cogging torque and core loss of the in-wheel motor can be optimized. The reduction of cogging torque is about 98%, the reduction of core loss is about 65%, and the reduction of the first harmonic is about 96%, and the conformity of the theoretical analysis results with the final simulation results shows that three-dimensional finite element method. It can be seen that the full-slot offset method can obviously restrain the cogging torque, core loss and the first harmonic. Therefore, the full-slot offset method proposed in this paper provides a certain reference value for the optimization design of cogging torque and core loss of in-wheel motor for electric vehicle.
  Keywords: electric vehicle; in-wheel motor; full-slot offset; cogging torque; core loss.
  DOI: 10.1504/IJVD.2022.10051369
   
  
• Power distribution methods of ultra-capacitor/battery hybrid power source for vehicular applications  
  by Benxiang Lin, Guizhou Ren 
  Abstract: Compared with traditional single power sources such as batteries, hybrid power source (HPS) for vehicular applications can reduce energy consumption and improve energy efficiency. The development of high-efficiency HPS for electric vehicle (EV) faces a huge challenge to meet the elevated energy demands under complex and variable working conditions. A HPS consisting of ultra-capacitor (UC) with high power density and battery with high energy density is recognized as having strong potential to meet this challenge. Reasonable power distribution control and optimization methods can significantly improve the working efficiency and application performance of UC/battery HPS. However, various control methods have different performance characteristics. It is not possible to claim that any one of them is the most effective method, usually making it difficult to quickly and accurately determine the most suitable control method for a specific application of UC/battery HPS. This paper aims to provide a comprehensive and transparent description of the known power distribution control methods that recently applied in various UC/battery HPSs. The article starts with an overview of typical energy storage technologies for HPS. After that, the power distribution control methods of UC/battery HPS are analysed and discussed systematically, such as explicit rule-based, fuzzy rule-based, model prediction, dynamic programming (DP), convex optimization, particle swarm optimization (PSO), and genetic algorithm (GA). Following this, a new UC/battery HPS is proposed, its operation principle is described, rule-based and fuzzy-based power distribution methods are initially formulated. The results of a simulation example verify the validity of the designed scheme.
  Keywords: ultra-capacitor/battery; hybrid power source; electric vehicle; power distribution method.
  
  
• Technology development strategies for electric vertical take-off and landing: focusing on the case of South Korea  
  by Yeon Jae Choi, Hyun Jin Cho, Ye Yun Kwun, Sanghak Lee 
  Abstract: Electric vertical take-off and landing (eVTOL) constitutes a promising type of personal air vehicle (PAV). More research pertaining to the detailed specifications for eVTOL configurations is therefore required. This research addresses the urgent need for eVTOL technology development strategies aimed at vitalising eVTOL aircraft commercialisation in South Korea. It does so by evaluating the relative importance and readiness level of technology using the analytic hierarchy process (AHP) and technology readiness level (TRL) analysis, respectively. Expert surveys are conducted based on a previously identified eVTOL technology tree. The ratings are then presented on a four-quadrant importance-performance analysis (IPA) matrix where each eVTOL technology is plotted according to its perceived relative importance and readiness level. The main categories of controlled autonomous flight and propulsion fall into Quadrant II (high importance and low readiness level), indicating that they constitute the highest priority among categories, and that a fast-follower strategy via the establishment of strategic partnerships should be pursued.
  Keywords: electric vertical take-off and landing; personal air vehicle; analytic hierarchy process; technology readiness level; importance-performance analysis; South Korea.
  
  
• Multi-objective optimiation of the passenger car seat frame using grey relational analysis and grey entropy measurement  
  by Zhiying Shan, Wei Wang, Jiangqi Long 
  Abstract: At present, more attention has been paid to the performance and lightweight design for passenger car seats. The optimisation design for seat frame is performed in this research. The innovation for this research is that a particular method of lightweight optimization is proposed according to the characteristics of seat frame. The best thickness-material scheme of the parts that needs to be optimised (opti-parts) is obtained by applying the method of grey relational analysis, grey entropy measurement, and average strain indices (GRA&GEM(ASI)). In addition, in order to verify the advantages of GRA&GEM(ASI), a comparison is made among serval different techniques. The results show that, not only the gross cost and gross mass of opti-parts are reduced by ?3.13 (16.68%) and 0.67kg (16.88%), respectively, but also the performance and reliability of seat frame is well guaranteed. The method of GRA&GEM(ASI) proposed in this work makes significant contributions effectively performed in multi-objective optimisation design for passenger car seat frames.
  Keywords: seat frame of passenger car; multi-objective optimisation; grey entropy measurement; grey relational analysis.
  
  
• Unique approaches to integrating semi-active suspension and active anti-roll bar control systems  
  by Sergio Guillen, Francis Assadian 
  Abstract: Automated control systems are commonly applied to road vehicles to improve certain dynamic behaviour. Active roll control systems are known to significantly improve roll dynamics (Zhu and Beshah, 2014). Additionally, there are a multitude of actuation mechanisms which can accomplish this, and each with unique benefits (Buma et al 2010; Mohan et al, 2012). Recent developments in the literature show successful control integration strategies, where one or more actuators are coordinated to achieve the same control objective(s). Improvements on dynamics behaviour and safety (distribution of actuator demands) are some of the benefits of integrating standalone control actuators (Assadian and Edo, 2006; Her et al., 2013). In this paper, the frequency domain, model-based control design method known as Youla parameterisation is applied to road vehicle models equipped with an active anti-roll bar and continuously controlled suspension dampers (CDC). Using this methodology, this paper demonstrates two novel strategies for integrating CDC with Active Anti-Roll Bar (AARB) which accomplish steady-state roll angle reference tracking while improving transient roll motion.
  Keywords: Youla parameterisation; integrated control; continuous damping control; active roll control.
  
  
• Fully hydraulic synchronous steering control of a vehicle based on gain fuzzy sliding mode variable structure  
  by Guang Xia, Jianshan Chen, Xiwen Tang, Linfeng Zhao, Shaojie Wang 
  Abstract: Aiming at the problem that the expected steering curve determined by the existing methods has poor traceability and cannot achieve synchronous steering, a method for determining the expected steering curve and its feasible area is proposed. Aiming at the uncertainty of system disturbance and the nonlinearity of oil leakage, based on the combined reaching law, sliding mode control is adopted, and the saturation function is introduced instead of the sign function, which imposes certain constraints on the control system. Aiming at the problem that the combined approximation law lacks gain adaptation, a fuzzy rule table based on wheel angle and angular velocity is formulated, and the gain fuzzy sliding mode control is realised. Simulation and experimental results show that the expected steering curve based on steering efficiency has good tracking performance; the gain fuzzy sliding mode variable structure control has excellent dynamic response characteristics and control precision. It can effectively eliminate steering deviation and realise full hydraulic synchronous steering of steering system.
  Keywords: full hydraulic steering system; synchronous steering; fuzzy sliding mode control; expected turning curve; steering deviation.
  
  
• Experimental performance comparison of R1234yf and R134a automobile air conditioning systems employing a variable capacity compressor  
  by Erkutay Tasdemirci, Ertan Alptekin, Murat Hosoz 
  Abstract: The use of refrigerants from the hydrofluorocarbon family has been restricted owing to their high global warming potential, and the manufacturers have been using R1234yf recently, a refrigerant from the hydrofluoroolefin family, as a substitute for R134a in mobile air conditioning (MAC) systems. In this study, a laboratory MAC system with a variable-capacity compressor was set up, and its comparative energetic and exergetic performance was evaluated for the cases of using R1234yf and R134a by changing the test conditions in a wide range. The results revealed that the system with R1234yf provided on average 13.7% less cooling duty and 12.8% less coefficient of performance based on the total power input relative to the system with R134a. Furthermore, the system with R1234yf destructed on average 18.9% more exergy per unit cooling duty. Excluding the condenser, the components of the R1234yf system destructed more exergy per unit cooling duty than those of the R134a one.
  Keywords: R1234yf; R134a; exergy; automobile; air conditioning; variable-capacity compressor.
  
  
• Multi-objective optimisation of composite coil spring for vehicle suspensions  
  by Xiaokai Chen, Chao Li 
  Abstract: This work presented a general form of spring rate and strength prediction model and an optimisation method for developing a suspension FRP coil spring. The prediction model can deal with an arbitrary sequence of layers instead of widely used
  Keywords: fire-reinforced plastic; coil spring; stiffness prediction model; strength prediction model; optimisation design.
  
  
• Coupled electrothermal model and thermal Fault diagnosis method for lithium-ion battery  
  by Qiuting Wang, Wei Qi 
  Abstract: The dynamic behaviour of the lithium-ion battery system is analysed. The nonlinear parameters, residual errors and thermal faults of the battery model are studied. In our study, a coupled electrothermal model is established based on the cell electrical dynamic characteristics. The parameter identification algorithm is presented based on Lyapunov observer. The core temperature and surface temperature of the battery cell are calculated based on extended Kalman filter. We propose a new thermal fault diagnosis method and the residual generation scheme. The UDDS (Urban Dynamometer Driving Schedule) dynamic working condition is used to verify our electrothermal model and fault diagnosis method. The experimental results indicate that the thermal characteristics can be described and the thermal fault can be diagnosed more accurately.
  Keywords: lithium-ion battery; coupled electrothermal model; fault diagnosis; Lyapunov observer; extended Kalman filter; UDDS.
  
  
• The optimisation design of CFRP bumper beam based on ply compatibility  
  by Jing Chen, Sen Xu, Zhen Liu, Aotian Tang 
  Abstract: This study aimed to develop an optimization approach for carbon fibre-reinforced polymer bumper beams. First, we established a specific finite element model and conducted a high-speed crash simulation of a steel bumper beam to verify the accuracy of the model. Then, the shape and parameter of the section of the bumper beam were determined using an orthogonal experimental design, and the concept of ply compatibility constraint was proposed. Subsequently, the ply sequence and thickness were optimised using the multi-island genetic algorithm and the multi-objective particle swarm optimisation algorithm based on kriging surrogate model with adding-point strategy. Results showed that the section force of the energy-absorbing box of the bumper beam was reduced after optimisation. The indexes of intrusion and energy absorption were also improved to some extent compared with the original ones. A real vehicle experiment proved that the optimised bumper system met all the requirements on strength and crashworthiness, with 47.61% weight reduction.
  Keywords: bumper beam; carbon fibre reinforced polymer; ply compatibility; multi-island genetic algorithm; KMOPSO; kriging surrogate model.
  
  
• Investigation of drivetrain dynamics on low- ground using the brush model  
  by Jianing Yang, Georg Jacobs, Achim Kramer 
  Abstract: This article aims to investigate the influence of the low-friction ground on off-highway drivetrain dynamics. A comprehensive vehicle simulation model is established for this purpose. This vehicle model consists of three parts: the torsional drivetrain model, the vehicle body model of longitudinal dynamics and the tyre model with slip behaviour. To correctly reflect tyre slip behaviour, the brush model, which features a physical description of the tyreground contact patch, is applied. A group of simulations is carried out on the complete vehicle model, mainly from two perspectives: drivetrain eigen-modes and drivetrain transient response. For the drivetrain eigen-mode analysis, different tyre slip states and the transition process between these two states are taken into consideration. For the drivetrain transient response, the vehicle is assumed to drive over a patch of low-
  Keywords: low-µ ground; tyre slip model; brush model; torsional drivetrain model; drivetrain eigen-modes; drivetrain transient response.
  
  
• Design and analysis of the dual motor coupling drive system for electric vehicle  
  by Qiping Chen, Zhiyi Zheng, He Wang, Yiming Hu, Zhihui Xu, Jianqun Zhang 
  Abstract: In order to improve the efficiency of the drive system of electric vehicle, the main and auxiliary motors of the dual motor coupling drive system of electric vehicle are designed in this paper. Finite element analysis of the designed motor model was carried out by Maxwell 2D module, by analysing the operation performance of the two motors in the steady and transient fields, the changes of magnetic line, flux density distribution, electromagnetic torque and other parameters when the motor is working are obtained. The calculation results are basically consistent with the simulation results. The results show that the maximum output power of the main and auxiliary motors is 100 kW and 60 kW, respectively, and the maximum efficiency is 95.7% and 96.9% respectively. the parameters of the two drive motors designed are reasonable and the performance meets the expected requirements.
  Keywords: electric vehicle; dual motor drive; electric drive; coupling drive system; electromagnetic design.
  
  
• External rotor permanent magnet-less electric motors for traction application: a review  
  by Sathyanarayanan Nandagopal, Lenin Natesan Chokkalingam 
  Abstract: Electric Vehicles (EVs) demand variable speed drives with high starting torque, high power density, and appropriate speed-torque characteristics. Owing to this, the EV industry widely considers permanent magnet (PM) motors for traction in powertrains. However, the harmful environmental impacts of the PM open the doors to magnet-less machines such as induction motors, synchronous reluctance motors, switched reluctance motors and flux switching motors as alternatives. Direct-drive in-wheel external rotor motors are an appropriate choice in traction applications to mitigate transmission losses. This paper thoroughly overviews the magnet-less machines with in-wheel external rotor topology. The discussions are based on magnetic structure variations, winding topologies, parameter optimisation, control algorithms, and mechanical aspects such as thermal and structural aspects involved in these machines. Further, other applications with external rotor motors are also discussed at the end.
  Keywords: electric vehicle; external rotor; induction motor; synchronous reluctance motor; switched reluctance motor; Flux switching motor; magnetic structure; winding topologies; optimisation algorithm; control algorithms; mechanical aspects.
  
  
• A method for analysing the lateral stability of wheeled farm tractors by obstacles on slopes  
  by Jiangyi Han, Yuhang Wang, Chenxi Sun 
  Abstract: A large number of tractor rollover
  Keywords: wheeled tractor; dynamic model; lateral stability; obstacles on slopes.
  
  
• Multi-PMSM adjacent cross-coupling iterative learning synchronisation control  
  by Yadi Zhou, Mingzhu Xu, Shaohua Li 
  Abstract: For the current widely used adjacent cross-coupling control strategy, when the number of motors is large, the control structure is complex and the calculation is difficult which makes it hard to access the demand of simple and efficient high-precision synchronisation control. The adjacent cross coupling control structure is studied, and an iterative learning controller is designed. A new multi motor speed synchronisation control strategy is proposed, which reduces the complexity of the control structure. The simulation and experimental data prove that the control algorithm has strong robustness. Compared with the traditional adjacent cross-coupling control method, the synchronisation error of the system can be reduced by 78.17% and the tracking error can be reduced by 62.40%, which effectively improves the control accuracy of multi-motor synchronisation operation.
  Keywords: permanent magnet synchronous motor; vector control; synchronous control; adjacent cross coupling control;.
  
  
• Derivation of vehicle dimensions at the early concept stage based on occupant posture  
  by Igor William Santos Leal Cruz, Thomas Gänsicke, Julian Francisco Sandiano, Christian Raulf, Thomas Vietor 
  Abstract: This paper presents a new method for deriving dimensional concepts for vehicles at the early concept stage. The derivation is centred on the posture of the occupants, which is calculated with statistical models and used to determine spatial requirements. Dimensions that do not follow directly from the posture calculations are determined with dimensional chains. The number of independent parameters is reduced by specifying dimensions that are assumed constant within a given vehicle segment. The application of the method is exemplified with different vehicle concepts. Vehicle length, width, height, and wheelbase calculated in the examples are comparable to those of existing vehicles. The use of non-proprietary, closed-form equations and the low number of independent parameters simplify implementation and application of the method.
  Keywords: vehicle dimensions; dimensional concept; concept stage; vehicle layout; driver posture; passenger posture.
  
  
• On the aerodynamic effects of the optimised DrivAer fastback model car under adverse situations  
  by I-Ying Chiang, Tung Wan 
  Abstract: In this study, the benchmark DrivAer model is employed for optimisation work of vortex generator locations with digital side mirrors through numerical simulation. Aiming for the best drag reduction via various installation positions by the kriging surrogate method, results show that for the best-achieved location, it is observed that the positive effect of drag reduction owing to an increase in the intensity of vortices; its wake also becomes weaker. In addition, in order to cope with fast-changing severe weather, the impacts of important physical phenomena such as gusty crosswind, heavy rain, and cornering are simulated and compared as well through detailed analyses of different physical quantities, force coefficients, and Strouhal number. Our simulations show that the gusty crosswind and cornering have the most negative influences on car aerodynamic performance, thus proving the effectiveness of the current approach in automobile design and safety. In addition, the combination of gusty and rain conditions is also elaborated in our work, and results show a similar trend as previous simulations.
  Keywords: DrivAer model; drag reduction; vortex generator; kriging model; gusty crosswind; heavy rain; cornering.
  
  
• Alternative designs for caster shims in commercial vehicles  
  by Sagar Jambukar, C. Sujatha 
  Abstract: Currently, in vehicles with front solid axles and leaf spring suspension arrangement, caster angles for the front steered wheels are incorporated using caster shims. The caster shim, a wedge-shaped structure, is inserted between the leaf springs and the axle, providing the necessary tilt of the kingpin axis known as the caster angle. Herein, the authors investigate the use of an alternative arrangement for introducing caster angle by incorporating the required tilt in the axle design, thereby eliminating the use of additional components, namely caster shims. Comparative numerical analysis for symmetric static loading and peak asymmetric loading for the existing and two other alternative designs has been discussed in detail in this work. The structural integrity of the proposed designs was found to be equally good, thus resulting in acceptability for practical use. Further, the proposed designs provide added flexibility in the choice of kingpin inclination (KPI) and caster angle, which will result in the improved kinematic and dynamic response of these vehicles. This has been achieved without compromising the functionality of the axle, with the advantage of eliminating a component and, therefore, notable cost savings to the automotive manufacturer.
  Keywords: caster angle; caster shims; alternative design; structural analysis.
  
  
• The effect of camber control on power consumption during handling manoeuvres  
  by Herman Hamersma, Janu Botha, Andries Peenze, Schalk Els 
  Abstract: Vehicle power consumption is receiving widespread attention in the industry. One of the approaches is to include camber control to reduce power loss during cornering. This approach changes the camber angle during cornering, reducing the steering angle needed. The published literature is limited to semi-empirical tyre models and simplified vehicle models. This investigation uses a physics-based tyre model and a full vehicle model to verify if the power savings reported in the literature are indeed achievable. The simulation results indicate that the reported power savings are indeed possible, but that the power saved during normal driving is limited. It is concluded that camber control is not suited to reducing power consumption during normal driving. A deeper investigation revealed that the use of radial tyres is one explanation for this finding. Camber control is thus not recommended as a power-saving strategy for practical applications using traditional radial tyres.
  Keywords: camber angle control; cornering losses; vehicle power saving; handling.
  
  

Special Issue on: Multi-Objective Design and Structural Optimisation of Vehicle Components with Nature-Inspired Optimisation Algorithms

• Integrated optimisation of two-speed powertrain parameters and shifting strategy for energy in electric vehicle  
  by Daoguang Zhu, Congbo Li, Lingling Li, Ying Tang 
  Abstract: In order to improve the economic performance and extend the range of electric vehicles (EV), an integrated optimisation method for the design and optimisation for powertrain parameters and shifting strategy are proposed. Firstly, the powertrain parameters are matched to ensure the dynamic performance of electric vehicles and the shifting strategy with comprehensive performance is designed based on the analysis of dynamic and economy performances. Secondly, a multi-objective integration model of powertrain parameter and shifting strategy optimisation is proposed to take the minimum energy consumption as the optimisation objective without sacrificing dynamic performance, which is solved by a multi-objective particle swarm optimisation algorithm. Finally, to verify the energy-saving performance of the proposed multi-objective integration problem, case studies have been conducted and a whole vehicle simulation model is proposed based on Matlab/Simulink platform. The simulation results show that the proposed method can effectively reduce the energy consumption and extend the range of electric vehicles under different driving cycle.
  Keywords: electric vehicle; powertrain parameter; shifting strategy; multi-objective integrated optimisation; particle swarm optimisation algorithm.
  
  

Special Issue on: New Energy Vehicles' NVH and Lightweight and Control Technologies

• Comparison of deep learning methods for predicting charging energy of power batteries  
  by Xuefeng Zhu, Guoliang Xie 
  Abstract: Accurate prediction of the electric vehicle charging energy is essential for power grid companies to rationally allocate power resources, customise appropriate tariffs and select the location of charging piles. Currently, machine learning methods have been widely applied in this field. Aiming to predict Electric Vehicles (EV) charging energy more precisely, this paper compares several machine learning methods and concludes that Long Short-Term Memory (LSTM) neural network has better behaviour. As the initial training data was incomplete, we supplemented the training data with MissFrorest neural network. We compared Back Propagation (BP), Xtreme Gradient Boosting (XGBoost), and LSTM networks for the prediction of charging energy, and found that LSTM has the best prediction effect, XGBoost has the second best, and BP has the worst effect. LSTM addresses the issue of gradient dispersion due to introducing time series, and thus has a better prediction effect. The experimental results show that Mean Absolute Error (MAE) and Root-mean-square error (RMSE) indices for four of five experimental vehicles using the LSTM algorithm are smaller than those using BP and XGBoost methods. Compared with the BP, XGBoost algorithms, the average reduction of MAE is 42.79%, 23.48%, and RMSE is reduced by 43.42%, 19.65%.
  Keywords: predicting charging energy; deep learning; power batteries; electric vehicles.
  
  

Special Issue on: Cyber Security in Internet of Vehicles

• Stabilisation of traffic flow by considering multiple information based on vehicle-to-vehicle communication  
  by Qian Li, Haiyang Wang, Dongfan Xie 
  Abstract: The rapid development of advanced technologies means that vehicles can share information with each other based on vehicle-to-vehicle (V2V) communication. It is expected that the V2V information can improve efficiency and stability of traffic flow, which has attracted much attention in traffic flow theory. To this end, this study develops an alternative car-following model with the consideration of V2V information. By using the linear stability theory, stability analysis is performed, and the string stability condition is obtained. The results indicate that V2V information can improve the stability of traffic flow, and traffic fluctuations can thus be suppressed. Case studies are carried out based on numerical simulations, and the results coincide with the theoretical ones.
  Keywords: vehicle-to-vehicle; communication; car-following model; stability analysis; traffic congestion.
  
  
• Research on service braking control strategy for heavy-duty truck on long downhill based on genetic algorithm  
  by Peilong Shi, Qiang Yu, Xuan Zhao, Pan Liu, Rong Huang 
  Abstract: While driving a heavy-duty truck on a long downhill road, the driver operates the pedal to brake depending mainly on driving experience and road condition. However, the drum temperature rises sharply when the service braking system works frequently. Hence, how to operate the brake pedal to avoid heat fading becomes an important issue. To solve this problem, a service braking control strategy for heavy-duty trucks based on genetic algorithm is proposed. In order to ascertain the main factor that causes the drum temperature to rise sharply, the constant speed control and the expected speed range braking control with different pedal forces strategies are simulated. It is found that several factors, including pedal force and speed range, have a significant effect on temperature, also the braking frequency and cumulative working time. Therefore, this paper proposes a multi-objective genetic optimisation algorithm on the braking control, adopting the constancy of braking efficiency, the degree of driver fatigue and driving safety as the objective function, optimising the brake pedal force, the desired speed range and average speed on long downhill roads. The results reveal that the multi-objective optimisation method based on genetic algorithm can slow down the rise in brake temperature, reducing the frequency of brake application and the driving intensity for the driver.
  Keywords: heavy-duty truck; braking control; driving safety; optimisation method.
  
  

Special Issue on: The Modelling and Control of Automated Guided Vehicle Systems

• Dynamic characteristics analysis of spatial suspension mechanisms based on instantaneous screws  
  by Guofeng Zhou, Yafei Wang, Zhisong Zhou, Jingkai Wu 
  Abstract: Multi-link, MacPherson and double-wishbone suspensions are commonly used in passenger cars. The dynamic characteristics of a vehicle are strongly affected by these independent suspensions. This paper presents a unified quarter-vehicle model which incorporates both the spatial suspension kinematics and the tyre dynamics for the dynamic analysis of the three spatial suspensions. In the quarter-vehicle model, it consists of a spatial suspension mechanism and a ground-wheel contact model. For a vehicle running straight ahead on the uneven road, the dynamic characteristics analysis using the quarter-vehicle model is divided into three steps. Firstly, for the quarter-vehicle model the corresponding instantaneous screws are determined at any instant. Then, the theory of screws is used to describe the kinestatics of the quarter-vehicle model. Finally, on basis of the kinestatic relations, the dynamic equations derived using the Lagrangian function are applied to the dynamic analysis. As to the feasibility of the theoretical method, different road disturbances are considered for the numerical examples. The simulation results respectively of the theoretical method and the widely used Adams/View software are compared to verify the numerical performances of the dynamic analysis.
  Keywords: spatial suspension mechanisms; quarter-vehicle model; instantaneous screws; kinematics; statics; dynamics; theory of screws.
  
  
• Parameter-space-based robust control of heterogeneous platoon with stochastic packet dropout  
  by Jiawei Wang, Fangwu Ma, Sheng Zhu, Yu Yang, Sukru Yaren Gelbal, Bilin Aksun-Guvenc, Levent Guvenc 
  Abstract: This paper presents a parameter-space-based multi-objective, robust CACC platooning controller for a heterogeneous vehicular platoon with stochastic packet dropout during inter-vehicular communication. The parameter space approach is adopted to optimise the gains of the robust controller, to handle the multiplicative uncertainty, and to project the robust performance requirements. The feasible region where internal stability and preceding vehicle following accuracy are satisfied is then visualised in the parameter space. Subsequently, the robust controller, which combines the feedforward loop and feedback loop, is developed by selecting the gain from the feasible solution area. The simulation results of a six-vehicle heterogeneous platoon are presented and evaluated to verify the efficiency of this control algorithm. The results show that string stability and comfort are well guaranteed by this robust controller, even for the heterogeneous platoon with stochastic packet dropout and the following error is limited to an acceptable range.
  Keywords: cooperative adaptive cruise control; stochastic packet dropout; heterogeneous platoon; parameter space approach.
  
  
• Active roll control for rollover prevention of semi-trailers with robust invariant set  
  by Echuan Yang, Chuanren Xie, Jian Ou, Senlin Zhang, Liang Qin 
  Abstract: To improve the roll stability of semi-trailers, a robust model predictive controller (RMPC) is designed. To analyse the vehicle dynamic behaviour, a nonlinear seven-degrees of freedom (7-DOF) vehicle model is defined. Based on the robust invariant set theory, and taking the uncertainty of the drivers driving behaviour into account, the maximal robust control invariant (RCI) set is calculated and its robustness is analysed. The N-step controllable sets of the vehicle are also solved. An anti-roll controller considering multiple constraints is designed based on the robust model predictive control theory. Simulation results show that the controller can keep the lateral load transfer rate within 0.7 and make the state variables converge. In addition, the controller can reduce the lateral acceleration by 50% in the step steering input test.
  Keywords: anti-roll control; invariant set; robust control; model predictive control; semi-trailer.
  
  
• Design of remote control smart car with two-way information communication  
  by Hongyan Qin, Ben Zhang 
  Abstract: This paper takes Freescale's remote wireless control smart car as the research object, completes the design of the main control board hardware circuit and the upper controller remote control software, and realises two-way information communication. The smart car collects the vehicle position signal by the CMOS image sensor, and transmits the image to the controller in real time by the APC220 wireless module. The XS128 microcontroller receives the control instructions sent by the controller, and drives the DC motor to control the smart car. The single-chip microcomputer collects the pulse signal of the wheel speed through the photoelectric encoder, which is captured by the MCU for PID closed-loop control. Tests show that the smart car and the controller can achieve error-free data transmission in a long-distance, multi-interference environment, and have good stability and obtain real-time control information.
  Keywords: wireless remote control; smart car; two-way information communication; anti-jamming design.
  
  

Special Issue on: Vehicle Design Processes

• The design and test of circular-cutting and middle-placing windrower for oilseed rape  
  by Haifeng Luo, Xiao Xiao, Beibei Zhang, Xu Li, Mingliang Wu, Chunyun Guan, Wei Xie 
  Abstract: An electric-drive circular-cutting and middle-placing windrower for oilseed rape is designed. Circular cutter adopts the cutting method that a chain-driven movable blade is combined with upper and lower double fixed blades, and designs a double-support circular cutter as well. Moreover, the symmetrical hugging and middle-placing reeling device is designed through artificial reeling operation. The simulated and kinematic analysis of the reeling device is done as well. The simulated analysis results show that the reeling track meets the operation requirement and the reeling devices have a good effect on the rape plants. The intelligent synchronous reeling control is designed on the reeling device drive. The field test of the prototype showed that the placing angle of the windrower was 11.48
  Keywords: circular cutting; symmetrical pushing; intelligent synchronous control; oilseed rape; windrower.
  
  
• Temperature and humidity optimisation control of cold chain vehicle carriage based on grey wolf algorithm  
  by Yulong Wan, Xinchun Li 
  Abstract: There are some problems in the traditional temperature and humidity control of cold chain transportation vehicles, such as poor control effect, poor real-time control, etc. The paper introduces Descartes coordinate system to construct the air motion tensor model in the carriage of cold chain transportation vehicles. The influence parameters of temperature and humidity of cold chain transport vehicles are divided into different temperature and humidity parameters. The grey wolf algorithm is used to search for the optimal solution of humidity influence parameters, and different wolf fitness models are constructed to determine the optimal solution of parameters to realise optimal control. The comparison shows that: the control deviation of temperature and humidity of cold chain transport vehicle compartment is always lower than 0.4, and the control efficiency coefficient is higher than 0.9.
  Keywords: cold chain transport vehicle; compartment temperature and humidity; Gray Wolf algorithm; tensor model; temperature and humidity comprehensive parameters; comfort index.
  
  
• Research on collaborative lane changing control method of unmanned vehicle based on internet of vehicles cooperation  
  by Haibo Zhang 
  Abstract: In this paper, a new method of coordinated lane change control for unmanned vehicles based on the cooperation of vehicle network is proposed. The paper analyses the vehicle lane change strategy, calculates the distance between the self vehicle and the front vehicle without collision and tail, and preliminarily plans the track of lane change according to the environmental information obtained from the visual environment perception part. With the support of the collaborative model control of the vehicle network, the Kalman predictor and SIFT feature extraction method are used to obtain the information of the motion and position of the unmanned vehicles, and realize the coordinated lane change control. The experimental results show that the error range of the operation failure rate is 1.00-2.31, the response time is 0.878 min, the vehicle lane change efficiency is high, and the practical application effect is good.
  Keywords: internet of vehicles collaboration; unmanned driving; vehicle coordinated lane change; control.
  
  
• Design of lane changing warning system for high speed vehicle based on fuzzy adaptive PID  
  by Xiaoguang An, Xiaofan Lu 
  Abstract: In order to overcome the low precision and efficiency of the traditional lane changing warning system for high-speed vehicles, a new lane changing warning system based on Fuzzy Adaptive PID is proposed in this paper. Firstly, the hardware structure of the control system is designed. The hardware mainly includes the early warning system control module and the fuzzy adaptive PID controller module to achieve high-precision early warning. In the software part of the system, in order to improve the turning sensitivity of the car, the fuzzy adaptive PID control algorithm is used for yaw rate feedback control, and the lane change warning algorithm is constructed. The experimental results show that, compared with the traditional lane changing early warning system, the early warning accuracy and efficiency of the designed system are significantly improved, and the maximum early warning accuracy reaches 96%.
  Keywords: fuzzy adaptive PID; expressway; lane change warning; DSP algorithm; yaw rate.
  
  
• New energy vehicle lithium battery life prediction method based on improved deep learning  
  by Zhiwen An 
  Abstract: The traditional methods of life prediction of lithium battery in new energy vehicles have the problems of large error and low efficiency. The paper puts forward a new energy vehicle lithium battery life prediction method. The capacity, internal resistance, terminal voltage and charge discharge cycle parameters of lithium battery for new energy vehicles are extracted to determine the key parameters affecting the life of lithium battery; The gradient descent method is used to improve the deep learning algorithm, and the improved deep learning prediction model is constructed. The key parameters affecting the lithium battery life are taken as the input of the model, and the optimal value is found to predict the lithium battery life of new energy vehicles. The results show that the capacity estimated by the proposed method is basically consistent with the actual capacity, and the life prediction time is always less than 2.2 s.
  Keywords: improving deep learning; lithium batteries; voltage curve; key parameters; life prediction.
  
  
• Path guidance method for unmanned vehicle based on improved potential field ant colony algorithm  
  by Zhuozheng Tang, Hongzhong Ma 
  Abstract: In order to overcome the problems of traditional path guidance methods such as long time consumption and many intermediate nodes in path planning results, a path guidance method for unmanned vehicles based on improved potential field ant colony algorithm is designed in this paper. From improved potential field function, pheromone update process and heuristic function 3 Angle improved potential field of ant colony algorithm, improve the obstacle avoidance ability of ant colony individuals and search capabilities, and then by determining the starting point and focus of elliptic search scope, in order to improve the optimal planning path searching efficiency and can achieve the optimal guide path. Experimental results show that the maximum time to generate the path guidance scheme is only 3.7s, the maximum TPI of the road is only 0.27, and the intermediate nodes of the planned path are the least and all paths are the shortest.
  Keywords: improved potential field ant colony algorithm; labour market; driverless vehicles; path to guide.
  
  
• Wear life prediction of vehicle brake pads based on image visual features  
  by Zuokui Li, Ruibin Jiang 
  Abstract: In order to solve the problem of poor prediction accuracy and stability existing in traditional prediction methods of vehicle brake pad wear life, this paper proposes a new prediction method of vehicle brake pad wear life based on image visual features. According to the visual features of the image, the gray moment features of the image are extracted, and the adaptive binary clustering is used to extract the target contour from the image. Aiming at the areas with different visual brightness, a three-dimensional physical model is established, and the friction coefficient and other parameters are calculated. Combined with the material characteristics of the brake pad, the wear life of the brake pad is predicted. The experimental results show that the proposed method has high detection accuracy, high level of stability maintenance, and its prediction reliability is improved. The maximum mutation index is less than 0.1.
  Keywords: image visual feature; vehicle braking; brake pad; wear life prediction;.
  
  
• Vehicle abnormal jitter detection based on multi-task convolutional neural network  
  by Jun Liu, Xiaoyuan Luo 
  Abstract: In order to overcome the problems of poor convergence, long detection time and high misjudgment rate existing in traditional methods, this paper proposes a vehicle abnormal jitter detection method based on multi-task convolutional neural network. The causes of abnormal vehicle jitter were analysed, and the equivalent taper of vehicles under different mileage was calculated to obtain the abnormal vehicle jitter frequency, and the time-frequency characteristics of vehicle vibration were obtained. The multi-task convolutional neural network is used to establish the calculation model of wheel matching geometric relationship under the condition of dithering, and the dithering degree of the vehicle body at different moments is obtained by sections, so as to realise the detection of abnormal vehicle dithering. The convergence coefficient of the method in this paper is higher than 0.9, the detection time of abnormal jitter is always below 1.2 s, and the lowest misjudgment rate is only 0.6%.
  Keywords: multi-task convolutional neural network; dithering detection; integral method; dithering frequency; equivalent taper.
  
  
• Ride comfort parameter optimization of an 8x8 armoured military vehicle using Taguchi method  
  by Berkay Celik, Namik Kilic 
  Abstract: Design parameters in military vehicles at the conceptual design stage have an impact on the results that will affect the fatigue of the driver. This article suggests the Taguchi optimization method to determine the most comfortable design parameters for the driver of an 8x8 military vehicle in difficult terrain conditions. Taguchi is an experimental design method that makes it possible to achieve results with a much smaller number of experimental studies. The full vehicle model prepared in MSC Adams/Car was driven over the Aberdeen Proving Ground (APG) stabilization track and performed a double lane change test to get experiment results for Taguchi design. The objective function of the optimization was the amount of absorbed power generated in the driver's seat over the APG track. In addition to this, roll angle results in the double lane change test were evaluated in the optimization procedure. In the study, it was found which of the design parameters had a significant effect on vehicle ride comfort and handling. The equations that estimate both the vehicle ride comfort and the vehicle handling according to the design parameters were obtained. This study improved the ride comfort of a four-axle military vehicle driver using the Taguchi method and developed a procedure that could be used in future design studies.
  Keywords: military vehicle; ride comfort; optimisation; Taguchi method; absorbed power.
  
  
• Wear life prediction of vehicle mechanical parts based on grey Markov chain  
  by Haoge Peng, Ming Zhang 
  Abstract: In order to overcome the high prediction error rate of traditional methods, a wear life prediction method of vehicle mechanical parts based on grey Markov chain is proposed. The wear type, wear mechanism of vehicle mechanical parts and the relationship between wear type and surface damage form are analysed, and the wear amount of vehicle mechanical parts is calculated. Based on the calculation results of wear amount, the relative error and residual error of wear life prediction results based on GM (1,1) model are obtained by using Markov chain, and the wear life prediction results of vehicle mechanical parts are obtained under the condition of minimising the two. The experimental results show that the accuracy of this method is 58-92%, the maximum error rate is 4.5%, the minimum error rate is 0.9%, and the average output time is 1.16 s.
  Keywords: grey Markov chain; mechanical parts; wear life prediction; relative error; predicting residual.
  
  
• Vibration fault detection of vehicle transmission gearbox based on time-frequency analysis of non-stationary signals  
  by Zhongli Shen, Qiyue Xie, Fei Jiang, Yi Huang 
  Abstract: The traditional vibration fault detection method of vehicle transmission gearbox cannot realise feature extraction of a non-stationary fault signal, which results in a large error of detection and low fault detection rate. Therefore, this paper proposes a new method of vehicle transmission gearbox vibration fault detection based on non-stationary signal time-frequency analysis. The components of the transmission gearbox are analysed, and the transmission path of vibration fault signal of transmission gearbox is obtained according to its structural characteristics. The time-frequency characteristics of non-stationary signals are extracted by the empirical mode method to complete the vibration fault detection of the transmission gearbox. Experimental results show that the proposed method has high detection accuracy and high detection rate under the premise of amplitude and phase modulation of fault signal.
  Keywords: vehicle transmission gearbox; vibration fault; non-stationary signal; time-frequency analysis; optimal observation signal.
  
  
• Design of BLDC motor drive system using alternative controllers for performance evaluation in electric vehicle applications  
  by Mohamraj Nandakumar 
  Abstract: Electric vehicles have emerged as a promising and important alternative means of transportation, replacing IC engine driven automobiles, which use fossil fuels. One important feature to be incorporated in an electric automobile is regenerative braking for extending the operating range. Accordingly, BLDC motor-based power electronic drive systems capable of energy regeneration have become attractive. This paper discusses the automobile dynamics, covering road friction, aerodynamic forces, transmission systems and calculation of tractive force. The time dependant profile of the reflected torque and speed variables at the motor shaft are computed and used as reference data for an intelligent controller. Here, a multi-loop control scheme has been developed, whose gain parameters are tuned based on two alternate algorithms viz., PSO (Particle Swarm Optimisation) technique and MNFIS (Multiple Neuron Fuzzy Inference System) for comparison. Simulation results for two power circuit regeneration topologies with the above control algorithms are presented. The experimental part is a representation of profile based operation, which deals with the application of the PMBLDC motor-based drive system for powering a passenger car and the evaluation of the system performance. Regeneration of power is validated in a laboratory setup and recorded.
  Keywords: BLDC motor; electric vehicle; MNFIS; PSO.
  
  

Special Issue on: Advanced Safety Design and Control for Electric Vehicles

• Research on stability of high-speed autonomous vehicles based on linear time-varying model predictive control  
  by Xiaoming Liu, Fei Liu, Jingbo Guo 
  Abstract: A stability control method of high-speed autonomous vehicles based on linear time-varying model predictive control (LTV-MPC) considering the impact of road environment is proposed. To ensure the accuracy of the prediction model and the driving stability of the vehicle, a yaw dynamics model is established considering the road curvature, lateral position deviation and tire slip rate. In order to reduce the influence of the road environment on path following effect, the reference road is segmented by B
  Keywords: autonomous vehicles; linear time-varying model predictive control; MPC; dynamics; handling stability; road curvature; path following.
  
  
• Steering and braking combined path tracking control considering the reserve potential of tyre force  
  by Shaosong Li, Feng Wang, Haitian Xu, ZongHao Li, Gaojian Cui 
  Abstract: The coordination control of the steering and braking system is the key technology for vehicle stability control under high-speed and low adhesion limit conditions. The concept of equal reserve capacity of tyre longitudinal and lateral forces is proposed in this paper, which provides a novel idea for tyre force distribution. On this basis, a steering and braking combined path tracking control method based on model predictive control is proposed to guarantee vehicle path tracking performance. Research results show that the proposed method enables the vehicle to steadily and accurately track the planned trajectory under high-speed and low-adhesion condition. Compared with the schemes in other methods, the reserve margin of the tyre force is greatly improved in the proposed method, thus enabling the tyre to exert greater control potential.
  Keywords: trajectory tracking; steering and braking combination; model predictive control; reserve potential of tyre force.
  
  
• A new torque ripple suppression strategy based on the CSA for PMHM of electric vehicles under New European Driving Cycles  
  by Yao Zhang, Xiaodong Sun 
  Abstract: This paper presents a new torque ripple suppression strategy for a permanent magnet hub motor (PMHM) of electric vehicles' drive. With the complex characteristics such as nonlinear time delay and multi-dimension presented by the PMHM, the traditional PID controller has been unable to meet the requirements of the control system. Thus, the cat swarm algorithm (CSA) is introduced to improve the accuracy of PID parameters thanks to its good global search ability. Moreover, it is found that the proposed CSA-PID in the outer loop can obtain better performance such as smaller torque ripple and faster dynamic response both in steady and dynamic state compared with the traditional PID controller. Finally, the strategy proposed in this paper was applied to the vehicle model through HIL test platform. The possibility of applying the strategy proposed to EVs was verified under the New European Driving Cycle.
  Keywords: permanent magnet hub motor; cat swarm algorithm; torque ripple suppression; New European Driving Cycle.
  
  
• Research on crashworthiness and lightweight of frame body based on load path and material selection  
  by Tingting Wang, Ruoyan Dong, Yuechen Duan, Dongchen Qin 
  Abstract: In order to effectively optimise the frame body structure and match the performance of lightweight materials with the function of body structure, a material-structure optimisation framework of multi-material frame body is proposed to improve the lightweight and collision safety at the same time. Firstly, in order to improve the crashworthiness of the frame, the equivalent static load method is used to analyse the load path of the frame body to obtain the optimal structure. Secondly, the crashworthiness evaluation method based on evolutionary structural optimisation method is used to evaluate each member of frame body, which provides the basis for material selection. Finally, the material index is introduced to establish the material library. According to the deformation evaluation results, the material selection method based on bubbling method is used to select materials orderly to match the function of members, and the multi-material frame with the objective selection scheme is obtained. In this study, the proposed method is demonstrated by the lightweight of racing car body. The results show that the body mass is reduced by 25.60 kg after the lightweight design, and the crash safety is improved. Therefore, the proposed optimisation framework of multi-material frame body.
  Keywords: frame body; lightweight; load path; material selection.
  
  

Special Issue on: Advanced Design and Automation Solutions for Offshore Vehicles

• Network-based formation control of unmanned autonomous systems with directed topologies  
  by Wenjian Zhong, Yuanqing Wu, Yanzhou Li 
  Abstract: The formation control of unmanned autonomous systems with nonlinear dynamics and directed topology is studied in this paper. By virtue of an ultra-wide bandwidth (UWB) localisation system, the relative position between each follower and the neighbouring agents can be obtained. A formation control condition for unmanned autonomous systems is derived by appropriately constructing a Lyapunov function. Further, a formation controller is designed to form the formation of all autonomous agents and reach the consensus of velocities. Some parameters are designed to ensure the feasibility of the formation controller. The effectiveness of the formation control protocol is verified by numerical simulations.
  Keywords: unmanned autonomous systems; formation control; directed topology; ultra-wide bandwidth.
  DOI: 10.1504/IJVD.2022.10051672
   
  
• FlameNet: a lightweight convolutional neural network for flame detection and localisation  
  by Xing Hu, Mei Li, Dawei Zhang 
  Abstract: Accurately and efficiently detecting and localising the flame is critical for preventing fire disasters. However, most high-performance deep models require high hardware resources, making them hard to deploy on edge or mobile intelligent devices with limited computation and storage resources. This paper proposes a lightweight deep convolutional neural network, called FlameNet, for flame detection and localisation in the real world. The proposed FlameNet is derived from YOLOv4 with the following modifications: first, MobileNetV2 replaces the CSPDarknet53 as the new backbone network of YOLOv4; second, the coordinate attention module is added to the inverted residual linear bottleneck of MobileNetV2; third, the depthwise separable convolutions is used in PANet of YOLOv4. The above modification significantly reduces the number of parameters and computation and improves detection accuracy. Considering the diversity and complexity of flames, and that no large-scale public dataset is available, we make a Real-World Flame (RWF) dataset containing 13,129 images from actual flame and fire disasters in real life. Qualitative and quantitative analysis and comparisons of experimental results demonstrate that the accuracy and efficiency of the proposed FlameNet for flame detection outperform the original YOLOv4 and the other relevant models. It is worth noticing that the number of parameters is only 1/6 of the original YOLOv4, which demonstrates that FlameNet is more suitable for deploying on edge or mobile devices.
  Keywords: flame detection; flame localisation; FlameNet; lightweight model.
  
  
• Integrated behaviour decision-making and trajectory tracking for dynamic collision avoidance of an ASV using receding horizon optimization  
  by Jian Zheng, Duowen Yan, Jiayin Hu, Yun Li 
  Abstract: This paper develops a receding horizon optimisation scheme for integrated behaviour decision-making and trajectory tracking to ensure the dynamic collision avoidance of an autonomous surface vessel (ASV). We apply Q-learning to make behaviour decisions because manoeuvring habit requirements and COLREGS must be satisfied in dynamic collision avoidance scenarios. The heading course and vessel speed are considered to transmit the outcome of behaviour decision-making to a trajectory tracking model predictive control (MPC) controller. Next, a trajectory tracking nonlinear controller for the ASV is developed within the MPC framework, in which a set of nonlinear constraints is designed for collision avoidance. Specifically, depending on the heading course and vessel speed, the collision avoidance constraints can be switched to allow the controller to execute the behaviour decision. Simulation results verify the effectiveness of the proposed receding horizon optimisation scheme.
  Keywords: Q-learning; trajectory tracking; dynamic collision avoidance; unmanned surface vessel; model predictive control.
  
  
• Compressive sealing process in vehicle engineering  
  by Menghan Tong, Shichao Xiu, Xiaoshan Chen, Siyu Chen 
  Abstract: The paste reliability of sealing strips is very important for the continuous quality of vehicle NVH. Compared with straight-line paste and outer corner paste, the inner corner paste of the sealing strip is more likely to be invalid. To improve the inner corner paste reliability of the sealing strip, a compressive pasting process is proposed. The additional pressure generated by the compressive pasting process was also studied. A calculation model of the pressure on the inner fillet produced by the sealing strip is proposed, allowing the pressure to be calculated by the compression ratio. The additional pressure on the inner circle structure caused by the compression of the sealing strip was simulated. A pressure experiment of the compressive sealing strip was completed. The relationship between the compression and additional pressure from the sealing strip was obtained and verified.
  Keywords: vehicle engineering; sealing strip; compressive sealing; additional pressure; PSA; finite element analysis; capability study; molecular force; mechanical model.
  
  
• Image-based visual servoing of underwater vehicles for tracking a moving target using model predictive control with motion estimation  
  by Jie Liu, Jian Gao, Weisheng Yan, Yimin Chen, Bo Yang 
  Abstract: This paper introduces an image-based visual servoing (IBVS) target-tracking strategy for an underwater vehicle to track a moving target beneath the vehicle using a downward-facing camera. The relative position, orientation, and velocity of the moving target were estimated using a nonlinear unscented Kalman filter (UKF). Based on these estimated values, image Jacobian matrices with respect to the velocities of the vehicle and target were constructed. A nonlinear model predictive controller (MPC) was employed to generate the velocity commands for underwater vehicles by optimising the visual target trajectories predicted by the estimated image Jacobian matrix and the target velocity. To track the velocity commands, an adaptive neural network controller was employed considering the system uncertainties. Simulation tests were performed with a fully actuated underwater robot to verify the efficiency of the designed IBVS target-tracking strategy.
  Keywords: underwater vehicles; image-based visual servoing; moving target tracking; model predictive control; neural network; unscented Kalman filter.
  
  
• Experimental validation of an improved underwater sphere-target localisation scheme for an autonomous underwater vehicle manipulator system  
  by Tianchi Zhang, Yong Tan, Xing Liu, Zhenzhong Chu 
  Abstract: In this study, an underwater sphere-target localisation method based on non-parallel binocular vision for an autonomous underwater vehicle manipulator system (AUVMS) is investigated. Existing extraction methods for underwater targets require considerable processing time, such that the real-time requirements for an AUVMS are not satisfied, and the shape features of the targets are not considered. In this study, an underwater target extraction method with reduced processing time is developed based on the known target edge constraint. The experimental results show that the developed method requires less time than the existing target extraction methods and satisfies the real-time requirements. In addition, the localisation precision of existing target localisation methods is relatively low, which leads to a low rate of successful implementation for an AUVMS. To solve this problem, a secondary compensation-based target localisation method is developed. A theoretical analysis is also presented. The experimental results show that the developed target localisation method can effectively improve the localisation accuracy and rate of successful implementation.
  Keywords: AUVMS; target extraction; target localisation; secondary compensation; binocular vision.
  
  
• Method of improving the soil compactor's ride quality based on the optimal negative stiffness structure  
  by Nguyen Van Liem, Dengke Ni 
  Abstract: A new driver's seat suspension designed by the negative-stiffness-structure (NSS) and cab's isolation used by the hydraulic mounts are proposed to enhance the soil compactor's ride quality. A nonlinear vehicle dynamics model that considers the interaction between the wheel/drum and deformable terrains is established to evaluate the NSS's performance. Based on the genetic algorithm, NSS's parameters are optimised to further improve ride quality. The ride quality is evaluated through the displacement and acceleration of the seat and cab in the frequency and time domains. The research results are also verified via experiments. The results show that the root-mean-square (rms) and power-spectral-density of the seat and cab accelerations with the optimal NSS are strongly reduced in comparison without NSS. Especially, the rms seat's acceleration is markedly attenuated by 67.54% under the vehicle working condition. Therefore, the optimal NSS applied on off-road vehicle's seat suspension could enhance the ride quality.
  Keywords: soil compactors; seat suspension system; negative stiffness structure; ride quality; multi-objective genetic algorithm; off-road terrains.
  
  
• An algorithm for solving the travelling salesman problem based on improved particle swarm optimisation and dynamic step Hopfield network  
  by Jiahao Wu, Qianqian Duan 
  Abstract: The travelling salesman problem (TSP) is a typical combinatorial optimisation problem. Many practical applications, such as logistics distribution centre location and network routing design, can be transformed into TSP by simplification. With the increase in city scale, the optimal solution is difficult to calculate. Therefore, it is necessary to find an efficient and feasible solution algorithm. An algorithm based on improved particle swarm optimisation and a dynamic step Hopfield neural network is proposed in this paper. Simplify the energy function to reduce the parameters of the energy function and improve the calculation efficiency; because of the slow convergence speed of the Hopfield network with the fixed step size, the dynamic step size is used instead. At the same time, aiming at the problem that Hopfield easily falls into local minima, the idea of particle swarm optimisation is introduced. According to the idea of exchange sequence, the particle swarm optimisation algorithm is redefined. On this basis, the random inertia weight is used to enhance the searching ability, and the asynchronous learning factor is used to enhance the learning ability of particles. Experiments show that compared with the classical Hopfield network, this algorithm can accelerate the convergence speed, better avoid invalid solutions, jump out of possible local extremum points, and obtain the global optimal solution with higher probability.
  Keywords: Hopfield; travelling salesman problem; dynamic step size; PSO; random inertia weight; Asynchronous learning factor.
  
  
• DRNN-MIMO-PID control strategy for multi-point mooring system  
  by Zhang Guichen, Lu Run, Chen Mengwei 
  Abstract: A DRNN (Dynamic Recurrent Neural Network) MIMO (Multi-Input-Multi-Output) - PID (Proportional + Integral + Derivative) control scheme for MPMS (Multi-Point Mooring System) is proposed in this paper. MPMS has a spread-mooring configuration that consists of complex characteristics by asymmetrical layout of mooring radius, large geometric nonlinearity of the platform hull and marine circumstances. The winch motor driving mooring cable is controlled by MIMO PID, which is composed of position loop, speed loop and torque loop; they are in series and the winch motors of MPMS are in parallel relationship. The positive and inverse solutions of the MPMS model are established, the relationship between MPMS position and mooring cable is determined, the position control of the mooring motor is related to the MPMS position control through the mooring cable, the MPMS positioning control is achieved by DRNN-MIMO-PID, which PID control parameters are updated by the DRNN, which learns MPMS dynamic changes and its connection weight coefficients are optimised iteratively by the steepest gradient descent method, which was adapted to the minimum criterion of the square sum of position error. Dead band control and indirect torque control ensure that MPMS position tracks the desired trajectory. The proposed scheme was mathematically simulated, verified by four-point mooring hardware-in-the-loop system, and applied to a four-point mooring dredger. The results show that the DRNN-MIMO-PID strategy has the advantages of collaborative optimisation and anti-interference ability.
  Keywords: multi-point mooring; MIMO-PID; dynamic recurrent neural network.
  
  
• Improved duelling deep Q-networks based path planning for intelligent agents  
  by Yejin Lin, Jiayi Wen 
  Abstract: The natural Deep Q-network (DQN) usually requires a long training period because the data usage efficiency is relatively low due to uniform sampling. While the importance sampling (IS) can promotes important experiences and is more efficient in the neural network training process. In this paper, an efficient learning mechanism using the IS technique is incorporated into duelling DQN algorithm, and is further applied to path planning task for an agent. Different from the traditional DQN algorithm, the advantages of the proposed algorithm improves the sampling efficiency. In this experiment, four target points on the map are deployed to evaluate the loss and the accumulated reward. Simulations and comparisons in various simulation situation demonstrate the effectiveness and superiority of the proposed path planning scheme for an intelligent agent.
  Keywords: path planning; deep Q-networks; reinforcement Learning; importance sampling.
  
  
• Leader-follower formation transformation control based on priority model for unmanned surface vehicle in narrow waters  
  by Linling Wang, Gongxing Wu, Hao Luo 
  Abstract: This paper presents a strategy of formation generation and formation transformation for multiple unmanned surface vehicles (USVs) in narrow waters. In order to solve the problem of multi-USV transformation in narrow waters, priority model and virtual intermediate goal are adopted. Multi-USV formation can successfully pass narrow waters while maintaining its shape by using this method. The formation generation and transformation are controlled by back-stepping based sliding motion controller (BSMC). The combination of back-stepping method and sliding motion control has high robustness, and can deal with the unmatched uncertainty problem, which can ensure the real-time performance of the control and is easy to deploy on the actual USV. The simulation results show that the method can make the formation change quickly in narrow waters and make the formation pass smoothly, and the error converges to 0 in finite time.
  Keywords: formation control; formation transformation; priority model; multi-USV.
  
  

Special Issue on: Emerging Technologies in New Energy Vehicles for Better Safety and Economic Performance

• Multi-objective optimisation design for brushless electrically excited synchronous machines in electric vehicles  
  by Naixi Xu, Xiaodong Sun, Ming Yao 
  Abstract: This paper proposes a new multi-objective optimization method to obtain the best performance of brushless electrically excited synchronous machines (BEESMs). First, the initial design of the BEESM is carried out and the parametric model is established. After the optimization problem of BEESM is transformed into a mathematical model, all design parameters are divided into three subspaces by sensitivity analysis method and multivariate analysis of variance method. Each sub-space is optimized based on approximate models and multi-objective optimization methods. Select the optimal solution from the Pareto solution set according to the filter conditions. The three subspaces are optimized in order, and the iterative process will continue until the convergence condition is satisfied. The experimental results based on the finite element model (FEM) show that this method can reduce the computational cost of BEESM optimization and improve optimization efficiency. The motor optimized by this method has better performance.
  Keywords: finite element model; brushless electrically excited synchronous machine; multivariate analysis of variance; Pearson correlation coefficient; multi-objective optimisation.
  
  
• Comparative analysis of multi-level inverter driven PMSM drive in automotive application  
  by Rakesh Shriwastava, Jagdish Chaudhari, Mohan Thakre 
  Abstract: This paper presents the comparative hardware analysis of multi-level inverter PMSM drive on the basis of two level and Twelve Switch Neutral point clamped Inverter (TSNPCI) driven Permanent Magnet Synchronous Motor (PMSM) drive using the AVR microcontroller. Multilevel inverters offer several advantages compared with the conventional three-phase bridge inverter in terms of lower dv/dt stresses, lower electromagnetic compatibility, smaller rating and better output features. The PMSM can be a better candidate in automotive application owing to many advantages, including high power-to-weight ratio, high efficiency, and rugged construction. The comparative harmonic features of the inverter-driven PMSM drive with SVM were analysed. The proposed AVR microcontroller based TSNPCI driven PMSM drive gives better control performance of speed and torque response, good dynamic response, less distorted output, less harmonic distortion and lower costs. Owing to good speed response and less torque ripple, it is found suitable in automotive application.
  Keywords: twelve switch neutral point clamped inverter; multilevel inverter; space vector modulation; total harmonic distortion; AVR microcontroller.
  
  
• Optimisation of braking energy recovery for rear-drive electric vehicles based on fuzzy control  
  by Li Ye, Zhihao Wu, Wenjing Lv 
  Abstract: To further improve the use rate of braking energy recovery and ensure the stability and safety of braking, this paper comprehensively considers the braking dynamics and regenerative braking structure to optimise the control strategy of braking energy recovery. Fuzzy controller, regenerative braking module, and regenerative braking model of electric vehicle are established by Matlab/Simulink and AMEsim, respectively. The fuzzy controller is designed, and the classic series and parallel control strategy is compared with the braking control strategy based on fuzzy control. Research shows that compared with the traditional series and parallel control strategies, the fuzzy control strategy has a better effect on braking energy recovery. The braking conversion rate is increased by 11.9% and 21.2%, and the braking recovery rate is increased by 2.78% and 4.96%, respectively, with a better recovery capacity of braking energy, and can increase the vehicle driving range and improve the vehicle energy use.
  Keywords: electric vehicle; braking energy recovery; fuzzy control; joint simulation.
  
  
• Power-on downshift analysis of a seamless two-speed transmission in electric vehicles  
  by Yang Tian, Boyu Tong, Shilei Zhou, Xiaoyu Ji, Xiaorun Tian, Yahui Zhang, Xun Shen, Guilin Wen 
  Abstract: Electric vehicles (EVs) have many advantages against internal combustion engine (ICE) vehicles and have caught the interest of academics and industry together. The two-speed transmission can improve the overall power and expand the mileage of EVs. In this paper, the power-on downshifting tactics of a seamless two-speed transmission are studied. The seamless two-speed transmission is controlled by a one-way clutch and two brakes for shifting gears. To achieve smooth downshifting process, three control strategies are proposed to study the process of the power-on downshifts. Firstly, the mathematical model of the two-speed transmission for electric vehicles is constructed. Then, three downshift strategies are analysed based on a simplified mathematical model. In this study, the difference of vehicle jerk and friction work in different downshifting strategies is explored by keeping the gearshift time unchanged. After analysing the simulation results, the advantages and disadvantages of different gear downshift strategies are clearly summarised.
  Keywords: electric vehicles; two-speed seamless transmission; downshift control strategies; gearshift quality.
  
  
• Stability control for distributed drive electric vehicles confronting differences of phase angle between coaxial motors  
  by Yueying Zhu, Weiyan Wei, Chao Xing, Chengcong Zhen, Huyi Song 
  Abstract: To enhance the straight driving stability of a distributed drive electric vehicle (DDEV) actuated by switched reluctance motors (SRMs), a stability control strategy for the vehicle confronting wheel torque discordance caused by differences of phase angle (DPA) coming from motors on two sides is proposed in this paper. The potential influence of the DPA between coaxial motors on vehicle stability is studied based on the established SRM and DDEV dynamics models. Then, the stability control strategy eliminating DPA is proposed by introducing feedback control for vehicle yaw rate, after DPA calculator and control selector are designed. Finally, the stability control system including DPA control system, vehicle dynamics model, driver model, and SRM drive system is founded and carried out under conditions of two-wheel and four-wheel driving modes. The co-simulation results prove the stability control strategy can effectively eliminate DPA such that the straight driving stability is greatly enhanced in both driving modes.
  Keywords: electric vehicles; torque coordination control; differences of phase angle.
  
  
• Research on multi-objective intelligent shifting schedule of electric vehicle AMT considering ride comfort and economy  
  by Donghui Lv, Bo Zhu, Lin Yuan, Zhidong Liu, Xue Bai 
  Abstract: Considering the current shifting strategy of multi-speed AMT separates the steady-state shifting from the transient shifting process in the pure electric vehicle, it is difficult to a comprehensive improvement of shifting quality, dynamic performance, and driving economy. In this paper, taking advantage of the artificial intelligence technology, a Fuzzy Neural Network (FNN) based T-S model is established via obtaining the training data from skilled drivers' experience and expert knowledge. A two-speed AMT pure electric vehicle model is used to investigate the fuzzy shifting strategy performance. According to the co-simulation results of AMESim and SIMULINK, the average jerk of 10.006 is recorded, compared to the value of 16.472 based on an ordinary shifting schedule. The results show that FNN-based schedule fully reflects drivers shifting intensions in pursuing shifting smoothness, at the same time, improving vehicle dynamic performance with negligible economic performance loss.
  Keywords: two-speed AMT; gear shift smoothness; fuzzy neural network; intelligent shifting schedule.
  
  
• Influence of critical turning speed of pure electric mining dump truck on rollover and sideslip  
  by Weiwei Yang, Wenming Zhang, Nong Zhang 
  Abstract: Because vehicles often violate the speed limit on curved roads, rollover and sideslip accidents occur on curved roads frequently. Designing the speed limit value of the curve road is an important measure to improve the driving safety of vehicles on curved roads. Considering how sharply the mine road turns, the safe driving speed of vehicles on curved roads is proposed in this paper based on the critical state of vehicle rollover and sideslip. Through the dynamic analysis of the vehicle curve driving, the relationship between the maximum speed limit of the curve and the parameters such as the lateral slope, the lateral force coefficient, and the turning radius under different curve radii is discussed to avoid lateral sideslip when the vehicle is driving on the curve. The curve road's speed limitation under each parameter's influence is obtained by changing the relevant parameters.
  Keywords: pure electric mining dump truck; curved road section; steering speed; driving stability; uphill and downhill.
  
  
• Four-mass-PWA model-based robust H-infinity coordinated control strategy for MTP of DM-PHEV  
  by Cong Liang, Xing Xu, Feng Wang, Shaohua Wang 
  Abstract: The multiple actuators of plug-in hybrid electric vehicles (PHEVs) participating in mode transition process (MTP), including engine start, clutch slipping and engagement. However, the engine start and clutch slip process involved in the MTP may lead to complex dynamics. In this paper, a thirteen degree of freedoms dynamic model of dual motor plug-in hybrid electric vehicle (DM-PHEV) is built and according to the results of sensitivity analysis, the model can be simplified as a four-mass model which is more friendly to the design of controller. Furthermore, the non-linearities caused by the engagement of clutch are handled with a piecewise affine (PWA) modelling method, and the vibration attenuation is realized by designing a PWA model-based robust H1 coordinated control strategy. Simulation and hardware-in-the-loop (HiL) test demonstrate that compared with the controller based on conventional two-mass model, the vehicle jerk controlled by proposed controller based on four-mass model can reduce the vehicle by 89.38%.
  Keywords: mode transition; sensitivity analysis; four-mass model; piecewise affine; coordinated controller.
  
  
• Internal temperature prediction of solar car based on IAGA-BP neural network  
  by Tingting Zhang 
  Abstract: The instability of the interior temperature of the solar car during winter heating leads to a lot of unnecessary energy consumption. This paper proposes to predict internal temperature based on the improved adaptive genetic algorithm-back propagation neural network (IAGA-BP). Firstly, the traditional adaptive genetic algorithms crossover and mutation probability are improved to get the improved adaptive genetic algorithm. The improved genetic algorithm is used to optimise the BP neural network to overcome the disadvantages of the BP network algorithm, such as easy falling into the local extremum, low learning efficiency, and slow convergence speed. Then, an internal temperature prediction model based on IAGA-BP neural network is established. Finally, the results of IAGA-BP are compared with results based on the particle swarm optimisation-back propagation neural network model (PSO-BP). The experimental results show that the mean absolute and square errors of IAGA-BP temperature prediction are 0.2810 and 0.1070. However, the mean absolute and square errors of PSO-BP temperature prediction are 1.6087 and 0.5191. The IAGA-BP network has better prediction accuracy than the PSO-BP network. Therefore, IAGA-BP neural network temperature prediction model can reasonably predict the car temperature to achieve the purpose of energy-saving.
  Keywords: new energy vehicle; economic and environmental protection; adaptive genetic algorithm; BP neural network; temperature prediction.
  
  
• Energy consumption optimisation of a battery thermal management system for electric vehicles considering different cooling modes  
  by Yunfeng Hu, Nuo Deng, Xun Gong, Yao Sun, Hong Chen 
  Abstract: For electric vehicles, the energy consumption of the battery thermal management system is one of the key factors affecting driving mileage. To reduce the consumption in the summer, an energy optimization method for battery thermal management systems, in which the liquid-cooling mode and air cooling mode are directly considered actuators, is presented in this paper. First, the influence of the vehicle speed on the air-cooling efficiency is considered in the modelling process of the battery thermal management system. Second, the weighted sum of the energy consumption and temperature tracking error of thermal management system is considered as the optimisation objective function. Third, the high dimensional dynamic programming algorithm is used to solve the nonlinear optimisation problem to obtain the optimal control trajectory. Finally, the effectiveness is verified under different driving conditions.
  Keywords: dynamic programming; electric vehicles; battery thermal management system; energy optimisation; cooling mode; control.
  
  
• A comprehensive study for range-extended electric vehicles from the perspectives of the technology, policy, market, and design concept  
  by Fuquan Zhao, Xinglong Liu, Han Hao, Zongwei Liu 
  Abstract: This paper investigates the technical characteristics, policy positioning, and market trend of range-extended electric vehicles (REEVs) and explores the design concept for REEVs. The results show that REEV is the transition solution in the near to medium term to address the consumers range anxiety about battery electric vehicles (BEVs) and meet the dual credit policy for automotive manufacturers. The market penetration of REEVs will increase due to the subsidies withdrawn and battery raw material prices rising until the battery cost drops to a predictable value. The technical configuration of that engine generating electricity to drive the traction motor directly is the technology development direction for REEVs. The technical solutions of REEVs (component parameters) should be selected according to the vehicle segment and market positioning. To maximize the technical advantages of REEV, it should develop dedicated hybrid engines (DHEs) and optimize the energy management strategy for the specific REEV.
  Keywords: range-extended electric vehicle; technical characteristic; policy positioning; market trend; design concept.