International Journal of Vehicle Design (65 papers in press)
Steering energy optimisation strategy of steer-by-wire system with dual electric motors
by An Wang, Chunyan Wang, Wanzhong Zhao
Abstract: In order to improve the fault-tolerant ability of a steer-by-wire system, a dual-motor structure is introduced to improve the system reliability as well as the steering safety. However, the redundant motor will change steering energy consumption. Therefore, a dual-motor coupling steering (DMCS) strategy is proposed to minimise steering energy while maintaining steering stability. The proposed control strategy contains two layers, namely an upper stability controller and a lower energy optimisation controller. First of all, stability controller is designed to ensure the operational stability under external interference and model uncertainty. Then, the instantaneous overall efficiency is optimised based on the working point between main and auxiliary motors and the operating principles of energy optimisation controller in various modes are analysed. Last but not least, this paper formulates the optimal mode switch strategy and power split strategy on the premise of satisfying stability during steering process. Simulation results conducted by Matlab/Simulink demonstrate that the DMCS strategy can satisfy the stability demands at different steering conditions and realise the optimal allocation of energy between motors, thereby improving the efficiency of energy use.
Keywords: steer-by-wire system; vehicle stability control; dual electric motors; efficiency optimisation; power split.
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.
Marine predators algorithm and multi-verse optimization algorithm for optimal battery case design of electric vehicles
by Betül Sultan Yildiz
Abstract: This article focuses on the optimum design of a battery case of an electric racing car. Two recently developed metaheuristics, which are marine predators algorithm (MPA) and the multi-verse optimisation algorithm (MVO), are used to create an optimal design where the mass is considered as an objective function, and the geometric dimensions of the component are considered to be the design variables. The kriging surrogate modelling is used to obtain the proxy model to increase the efficiency of the optimisation. The results show the robustness of the MPA in the optimum design of the electric car components. The MPA can be used in other product development processes.
Keywords: marine predators algorithm; electric vehicles; battery case; shape design optimisation; multi-verse optimisation algorithm.
Artificial road input data synthesis: a full vehicle model case study
by Adebola Ogunoiki, Oluremi Olatunbosun
Abstract: In order to reduce the time and cost of developing a vehicle, it is important that virtual durability testing is carried out. In this research project, the aim is to predict the road input for the virtual durability test simulation of a new vehicle variant by transforming the data from a predecessor model using the vehicle's configuration parameters to generate a new and representative road input. To achieve this, a full vehicle model of a sport utility vehicle (SUV) is developed and validated with test data collected on a proving ground; this model is used to generate data to train and validate a NARX-based artificial neural network tool which is then subsequently used to predict the road input to the new variant of the vehicle. The use of artificial neural networks in this project shows one of the many potentials of artificial intelligence in developing virtual capabilities within the automotive industry.
Keywords: multi-body dynamics; artificial neural network; durability; computer aided engineering; CAE; road load data; RLD; full vehicle model; vehicle variant; QanTiM; SIMPACK; multi-body simulation; MBS.
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.
Steady-state modelling and analysis for a proportional electromagnet in a semi-active damper
by Xianju Yuan, Hongtao Ling, Tianyu Qiu, Jiwei Zhou, Tianyu Tian
Abstract: Achieving a modified method of reluctance, mathematical models are developed firstly. Then considering more details in materials, reference boundaries of currents and a method of mesh regulation, a finite element model is also established. Finally reflected through an instance, the maximum error within the effective range, less than 1 N, demonstrates improvements of accuracy of these mathematical models. Compared with results of experiments, the maximum error and fluctuations from the finite element method are evidently smaller than those of mathematical models. Therefore, such mathematical models and the finite element method would be helpful to obtain the steady-state force of complex electromagnets.
Keywords: proportional electromagnet; steady-state analysis; mathematical model; finite element model.
Development of a sorption thermal energy storage to support the thermal management of hybrid vehicles
by Georg Engel, Roland Kerschenbauer, Markus Hinteregger, Gregor Gregorcic, Anna Maria Fulterer, Waldemar Wagner, Wim Van Helden
Abstract: A sorption thermal energy storage is developed for the thermal management of hybrid vehicles. The thermal storage is charged using waste heat of the combustion engine, and discharged to provide heating and cooling for the battery and cabin, for example. A functional module of the storage system is assembled and assessed in experiment, where a cooling peak power of 2 kW and an average power of 1 kW are observed for 30 minutes. Assuming an optimised system design, this translates into key performance indicators of about 27 Wh/l and 55 W/l for cooling. Detailed system simulations show energy savings of 60% for cooling the battery during a worldwide harmonised light vehicles test cycle at elevated ambient temperature levels, saving 80 seconds for heating a chilled battery up to 20 deg. C and saving 26 seconds for preheating the combustion engine up to 80 deg. C.
Keywords: thermal management; e-mobility; hybrid vehicles; thermal storage; closed adsorption; co-simulation.
Research on an energy management strategy and energy optimisation of hydraulic hybrid power mining trucks
by Hongliang Li, Denglin Zhu, Lihua Shang, Ping Fan
Abstract: A design scheme of a parallel hydraulic hybrid mining truck (HHMT) is proposed, and its energy management and energy consumption optimisation are studied. A multi-disciplinary physical model is established, and a rule-based multi-mode conversion energy management strategy is formulated, combined with orthogonal experimental design (OED) to determine the optimal combination of parameters to minimise fuel consumption. Sequential quadratic programming (NLPQL) is also used to obtain the optimal solution on this basis. Through OED, the influence law of power system parameters and control parameters on the energy saving effect is obtained, and the influence of a parameter change under the best parameters on fuel consumption and energy storage (discharge), as well as the sensitivity of fuel consumption and energy storage(discharge),on driving conditions are quantitatively analysed. The effect of this energy management strategy is evaluated. Using the optimal parameters to simulate the HHMT on a joint simulation platform composed of Amesim and Stateflow, it is found that the actual vehicle speed can track the target vehicle speed very well. Compared with the original vehicle, the engine can work more often in the fuel economy zone, and fuel consumption is reduced by 11.39%, effectively reducing operating costs. The simulation results verify the correctness of the physical model and energy management strategy and prove the effectiveness of OED for fuel economy evaluation. This research may provide guidance and reference for HHMT research and development.
Keywords: hydraulic hybrid mining truck; energy management strategy; energy consumption optimisation; orthogonal experimental design; fuel consumption.
Linearisation modelling and active performance simulation of active engine mounts with an oscillating coil actuator for automotive powertrain
by Rang-Lin Fan, Jia-Ao Chen, Chu-Yuan Zhang, Zhen-Nan Fei, Pu Wang, Quan-Fa Wu
Abstract: Active engine mounts (AEMs) are key elements for improving automotive noise, vibration and harshness (NVH) performance. An accurate AEM model is crucial for its active control. This work focuses on the establishment and verification of a linear model for AEM with an oscillating coil actuator (OCA). Experiments and simulations of an actuator with an attached decoupling membrane and a conventional hydraulic engine mount (HEM) are employed to verify the fundamental linear models for an OCA and HEM. An integrated linear model for an AEM with an OCA is established and verified by experimental analysis of active characteristics. Based on the AEM linear model, three control algorithms, i.e., PID, fuzzy PID and FxLMS, are established to implement an active isolation performance simulation. The FxLMS is superior to the other two algorithms for an AEM considering the active performance for rotary machine.
Keywords: active engine mount; active hydraulic mount; active control mount; active control; oscillating coil actuator; linearisation modelling; lumped parameter model; active characteristics; passive characteristics; powertrain mounting system; automotive; rotary machine; NVH performance.
AUKF based unified estimation scheme for nonlinear vehicle dynamics
by Shouvik Chakraborty, Anindita Sengupta, Ashoke Sutradhar
Abstract: The paper presents an additive unscented Kalman filter (AUKF) based modular approach to estimate lateral vehicle dynamics and tyre forces. In this approach, a simplified single-track vehicular model and a dynamics-oriented tyre model are adopted to represent the vehicular motion. Subsequently, multiple observer modules for each dynamical state are designed and integrated into a Unified Estimation Scheme (UES-AUKF). Two additional non-modular observers using AUKF and EKF are designed for comparative analysis of estimation accuracy and computational efficiency of the designed scheme. The simplified model and the designed estimators are simulated using double lane change and sinusoidal manoeuvres for high and low surfaces, respectively, and the results are analysed. Thereby the scheme is further validated using real vehicle dataset for estimation accuracy. Simulation results for the simplified vehicle and the tyre model conform with the standard results with acceptable deviations. The proposed scheme exhibits improved accuracy with reduced computational time compared with the non-modular observers.
Keywords: UKF; vehicle dynamics; yaw rate; slip angle; tyre force; modular estimation; tyre model; lateral dynamics estimation; Kalman filter; bicycle model.
Development of a novel testing procedure and optimisation of a rubber spring using constrained simulated annealing algorithm for automobile clutch system
by Mehmet Onur Genç, Süleyman Konakçi, Necmettin Kaya, Samet Kartal, Ali Kamil Serbest
Abstract: Rubber compounds have widely used in many industry areas with many advantages, including in the automotive industry. However, the use of rubber-based springs within the clutch system of automobiles requires further investigation owing to the mechanical behaviour variations of rubber-based materials under dynamic conditions. In this study, a new methodology is proposed for the use of elastomer-based damper springs in automobile clutch systems. The design of the rubber damper spring and validation are comparatively investigated for an automobile clutch system, and a novel approach is developed. For this purpose, clutch usage on the automobile was simulated with a torsional fatigue test bench, which represents the loading and unloading case on damper springs at specific cycles and frequencies. NBR (nitrile rubber) was chosen as the sample rubber spring material, since it has representative material characteristics. As a result of the performed tests, a target stiffness value was obtained for the specified clutch requirements, and then a simulated annealing algorithm was coded in Python programming language and applied using specific design constraints from the response surface methodology.
Keywords: rubber damper; hyper-viscoelastic modelling; simulated annealing; torsional fatigue; clutch disc; powertrain system; system optimisation.
Design optimisation of a hybrid electric vehicle cooling system considering performance and packaging
by Kwang Jae Lee, Namwoo Kang, Michael Kokkolaras, Panos Y. Papalambros
Abstract: Optimal system design at the conceptual functional level, i.e., before the embodiment of the functions is determined in detail, focuses primarily on performance. Embodiment determines the geometry and position of subsystems and components, which must be packaged usually within strict spatial envelops to achieve compactness or other external requirements such as styling. Packaging objectives and constraints may therefore compete with performance ones, leading to redesign and costly delays if these conflicts are not addressed early in the design process. This paper presents a design optimization framework for coupled performance and packaging problems. Using the cooling system for a heavy duty tracked series hybrid electric vehicle as an example, we demonstrate the framework combining commercial CAD software with optimization tools and including pipe routing which is a basic requirement in many mechanical systems.
Keywords: performance; packaging; pipe routing; system design optimisation.
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.
Cool semantics of mini electric vehicles considering appearance attractive factors
by Le Xi, Su-nan Li, Hui Zhang, Jian-xin Cheng
Abstract: Today, the word cool has become a generic term to indicate approval and appreciation from audiences for a new design style of freshly released concept cars. To capture this cool style, this study investigated the appearance characteristics of mini electric vehicles (mini-EVs) using cool semantics. The cool semantic space of mini-EVs has been constructed through the cool-evaluation grid method (C-EGM), and the internal relationship between multiple cool semantics and appearance factors was identified by the quantitative analysis of quantification theory type I (QT-1). Then, satisfaction attributes of key factors extracted from QT-1 were subdivided by the fuzzy Kano model (FKM), to facilitate their adoption during the creation of designs by the designer. The results show that C-EGM and FKM can clearly deconstruct the concept and the essence of coolness products from multiple levels. Consequently, these can be used to promote the designers' accurate understanding of customer preferences of vehicle style and provide new ideas.
Keywords: cool semantics; attractive factor; evaluation grid method; Fuzzy-Kano model; quantification theory type I; mini electric vehicle.
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.
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: Revisiting Vehicle Dynamics and Control for Electrified and Autonomous Vehicles
Robust lateral and longitudinal stability control for delta three-wheeled vehicles with suspension system
by Martin Antonio Rodríguez Licea
Abstract: Typical (delta) three-wheeled vehicles, known as tuk-tuks, auto-rickshaws, and motorbikes, are well-known for their low performance at road curves compared with the tadpole or tilting configurations. Little research has been published regarding the risk of lateral rollover and trajectory tracking for these types of vehicle. There is no study about the skid or longitudinal rollover risks to the author's knowledge, much less about their mitigation. The delta three-wheeled vehicle (TWV) is the most widely used worldwide, and severe injuries and fatalities are frequent owing to the few safety systems they integrate. Furthermore, electrification provides different acceleration and weight levels that necessitate new driver assistance systems to mitigate such accident risks. In this paper, three new models for the skid and lateral and longitudinal rollover risks are proposed. Such models include the effects of a suspension system. They can be calculated in an actual application by measurements of chassis angles (by an inertial measurement unit, for instance) and information from the power-train control module (PCM). Even more, a robust lateral and longitudinal stability control (LLSC) is proposed to effectively mitigate the risks simultaneously, despite (bounded) parameter uncertainty. The control actions are performed by rear electric in-wheel motors (differential propulsion) and independent ABS braking in all wheels. The controller gains are obtained by the iterative resolution of an offline optimisation problem; semi-experimental (hardware-in-the-loop) tests are performed to show how the risks are diminished. Even more, the LLSC can effectively mitigate rollovers and skidding on low friction surfaces (with clear limitations) simultaneously.
Keywords: three-wheeled vehicle; lateral skid; rollover; robust control.
Vehicle sideslip angle estimation: fusion of vehicle kinematics and dynamics
by Xin Xia, Lu Xiong, Yishi Lu, Letian Gao, Zhuoping Yu
Abstract: The vehicle sideslip angle (VSA) estimation is vital to vehicle lateral safety control, such as electronic stability control and path following control. In this paper, a VSA estimation method is proposed based on fusing the vehicle kinematics and dynamics. First, the vehicle-kinematic-based (VK-based) VSA estimation method is provided by the global navigation satellite system (GNSS) and inertial navigation system (INS) integration system (GNSS/INS integration system). Then, the observability for the heading error which is related to VSA estimation error in the error state model of the GNSS/INS integration system is analysed. The heading error in GNSS/INS integration is not well observable and its estimation accuracy cannot be guaranteed when the acceleration in the horizontal plane is small and varies little. To improve the heading error estimation accuracy, a vehicle-dynamic-model-based (VDM-based) VSA estimation method is given and based on this method, a novel augmented heading estimator for the GNSS/INS integration system is designed. Besides, an intuitive heading error weighting strategy is presented to determine the heading error between the heading error from GNSS/INS integration system and that from the augmented heading error estimator. Finally, the proposed method is validated by a comprehensive test which includes double lane change, single lane change, and slalom manoeuvres. Results show that the VSA estimation absolute mean error of the proposed fusion method is 0.125
Keywords: vehicle sideslip angle estimation; heading error estimation; vehicle dynamics; information fusion; Kalman filter.
Rollover detection and prevention of a heavy-duty vehicle on banked and graded uneven road
by Zhilin Jin, Jingxuan Li, Shuwei Huang
Abstract: The roll performance of a vehicle with a flexible frame and solid axle suspension has been touched on in few current researches. To reveal the rollover mechanism of a vehicle with flexible frame and solid axle suspension on a banked and graded uneven road, a novel rollover index and an integrated control strategy for vehicle rollover are proposed. Taking the coupling of the roll motion of the sprung mass of the front axle with that of the drive axle into consideration, a 10-DOF dynamic model is established. Then, a novel rollover index is derived from the rollover dynamics. Moreover, an integrated control strategy combining active steering and active braking of the rear wheel is developed and optimised offline by a genetic algorithm. Finally, some numerical cases are studied under untripped and complicated tripped rollover conditions. Results reveal that the integrated control strategy has good robustness, which can prevent the heavy-duty vehicle rollover effectively and keep the drive intention simultaneously.
Keywords: rollover prevention; heavy-duty vehicle; flexible frame; banked and graded uneven road; tripped rollover.
Cooperative collision warning system design at intersections based on trajectory prediction and conflict risk evaluation
by Lin Zhang, Jiabei Gao, Bin Li, Haobo Sun
Abstract: A novel cooperative collision warning system based on trajectory prediction and conflict risk evaluation is proposed in this paper to reduce traffic accidents and fully guarantee driving safety at intersections. First, a vehicle kinematics model is introduced based on the constant acceleration model and constant turn rate and acceleration model, respectively, on straight and curved roads. The extended Kalman filtering is applied to integrate the signal of GPS and on-board vehicle sensors and filter the noise data of both to realise the real-time estimation of the vehicle's position. Then, based on the intersection's road geometry information, a cubic parabola model is established to simulate the driver's future manoeuvres. The vehicle model and the driver's future manoeuvres are combined to predict the future trajectory of the vehicle and surrounding vehicles in the future from 0 to 2 s. Considering the uncertainty in the prediction process, the Gaussian process regression is used to fit the vehicle's trajectory within 0 to 2 s in the future and further deduce the vehicle trajectory of the next 2-2.5 s. Finally, multiple circles are used to envelop the vehicle's shape to assess collision risk between vehicles. A conflict risk assessment model based on overlapping regions is established to timely alert drivers. Simulation results show that the proposed algorithm has a higher precision of trajectory prediction, and can warn the driver promptly and reduce the false alarm rate.
Keywords: cooperative collision warning system; intersections; trajectory prediction; conflict risk evaluation.
A priori map-based automated valet parking with accurate adjustment ability for automatic charging
by Yongsheng Wang, Yugong Luo, Weiwei Kong, Dexu Bu, Yanchen Ku, Fachao Jiang
Abstract: With the development and application of automatic charging systems for electric vehicles, there is a demand for increasing the accuracy of vehicle parking position. In this paper, a priori map-based automated valet parking (AVP) system with accurate adjustment ability is proposed. Firstly, the parking lot topological map is designed as a priori information for path planning. Then, a path coordination and optimisation strategy is applied to merge the global path and the parking path without transition curve. After that, a Forward Orientation and Reverse Lateral Position Deviations (FORLPD) control strategy is proposed to accurately adjust the connecting position of automatic charging system. This strategy uses the heading deviation and lateral position deviation for vehicle forward and reverse motion control, separately. Finally, experimental results on a real vehicle show that longitudinal and lateral deviations of vehicle parking position can be adjusted with satisfactory accuracy.
Keywords: automated valet parking; priori map; accurate adjustment; automatic charging; path coordination and optimization strategy; FORLPD control strategy.
An adaptive second-order sliding mode for IWM electric vehicle lateral stability control based on super twist sliding mode observer
by Jialin Li, Di Ao, Lina Lan, Jialin Liu, Rui Xiong
Abstract: To improve the lateral stability of the in-wheel motor electric vehicle, this study proposes an adaptive second-order sliding mode control (ASOSM) method based on a super twist side-slip observer (SMO). As the existing researches showed, the chattering phenomenon is naturally suffered by first-order sliding mode (FOSM) control. Besides, the second-order sliding mode (SOSM) control should know the boundary of the lumped uncertainties. To figure out these problems, the proposed ASOSM is achieved by adding a high-frequency term of the first derivative of the predesigned sliding surface. The control gains can be calculated by an adaptive law with no need for any information on uncertainties. Furthermore, the controller robustness is verified by changing tyre parameters and vehicle mass. The co-simulation results illustrate better control performance for the proposed controller. Also, the super twist side slip angle observer also gives good tracking results. Both the yaw rate and trajectory tracking results exhibit pretty well. Compared with the baseline FOSM and SOSM, a significant improvement for vehicle lateral stability and control efforts is indicated.
Keywords: in-wheel motor electric vehicle; lateral stability control; adaptive sliding mode control; super twist observer.
Trajectory planning, dynamics modelling and trajectory tracking method for off-road autonomous vehicles considering the road topography information
by Boyuan Li, Bangji Zhang, Haiping Du, Yang Wu, Shengzhao Chen
Abstract: The road topography can significantly affect the tyre vertical load and the vehicle dynamics response in off-road scenarios, which will greatly impact the autonomous vehicles stability, trajectory planning and trajectory tracking performance. However, the road topography information is not given much attention in the current literature. This study focuses on the local trajectory planning and tracking method by assuming that waypoints along the global route are available. First an innovative spatiotemporal-based local trajectory planning algorithm is proposed to select the desired trajectory with minimum road gradient and bank angle. After that, a 8 Degrees-of-Freedom (DOF) vehicle dynamics model is proposed to better present the dynamics performance. Finally, a double-layer control strategy for trajectory tracking is designed to follow the desired planned trajectory. It is proved by simulation results that the peak bank angle and road gradient could be avoided, and the trajectory tracking performance is improved by the proposed method. Furthermore, the omni-directional vehicle is shown to have better vehicle stability performance than the vehicle with Front-Wheel Steering (FWS) characteristics.
Keywords: trajectory planning; trajectory tracking; bank angle; road slope.
Automotive G vector control for comfort improvement and experimental verification
by Chunbo Liu, Hongliang Zhou, Houhua Jing, Zhiyuan Liu
Abstract: The normal vehicle lateral motion control systems such as ESC work only when the vehicle tends to be unstable. Expert driver operations show that the longitudinal acceleration can be adjusted during turning to improve ride comfort and avoid vehicle instability to a certain extent. The brake-by-wire system can automatically adjust the longitudinal acceleration without relying on the driver to apply braking to improve the lateral motion performance. Starting from comfort evaluation during curve movement, the relationship between comfort and lateral acceleration is analysed. In order to reduce control fluctuations and improve real-time control, the steering wheel signal is selected as input and a fuzzy rule is proposed as the G vector control law. Finally, the control method is applied on an experimental vehicle through a real-time simulation system to verify its effectiveness.
Keywords: ride comfort; brake by wire; fuzzy control; G vector control.
Four-wheel independent steering system control of distributed electric vehicle based on heterogeneous multi-agent
by Niaona Zhang, Haolin Li, Shaosong Li, Yang Liu
Abstract: In order to improve the active safety and yaw stability of the distributed drive electric vehicle, this paper proposes a four-wheel independent steering finite time control method based on the theory of a heterogeneous multi-agent. Firstly, considering the system uncertainty and external interference, the topology is established based on the communication and hardware connection of each steering system. Then considering the uncertain time-varying delay of the system control network and the real-time calculation burden of the wheel redundancy system, a finite time robust control method of the wheel steering system is proposed on the basis of the event-triggering of a heterogeneous multi-agent, which can avoid the calculation process of matrix inversion in the integrated control of the whole vehicle steering system. Finally, through the simulation experiments on step input, continuous sine and double shift line, it is verified that the method proposed in this paper can stably follow the ideal value and can improve the vehicle yaw stability.
Keywords: electric vehicle; four-wheel independent steering; heterogeneous multi-agent; event-triggering; finite time.
Optimised robust path-following control of autonomous vehicles with pole constraints
by Yixiao Liang, Yinong Li, Amir Khajepour, Ling Zheng
Abstract: This paper presents a robust output-feedback guaranteed-cost control strategy for the path-following control of autonomous vehicles. First, the model of vehicle dynamics and path-following is established, which takes the uncertainties of cornering stiffness into account. Then, to deal with such uncertainties and improve the transient performance, a robust guaranteed-cost controller is introduced with the regional pole constraint ability. Considering that it is expensive and difficult to measure the side slip angle accurately, the proposed controller uses an output-feedback scheme without side slip angle information. Moreover, the particle swarm optimisation algorithm is selected to optimise the performance index of the guaranteed-cost controller such that the priorities among different objectives can be decided reasonably. Simulation results demonstrate the effectiveness of the proposed controller and its advantages over previous studies in the presence of parameter uncertainties.
Keywords: autonomous vehicle; path-following control; robust guaranteed-cost control; output-feedback control; particle swarm optimisation.
Special Issue on: New Energy Vehicles' NVH and Lightweight and Control Technologies
A clustering-based simplification of massive automobile-bodies point cloud for lightweight design
by Yu Zhou, Yue Song, Qi Zhang, Yan Wang, Farong Du, Shuiting Ding
Abstract: Adaptive simplification for massive and large-scale automobile-bodies point cloud obtained by 3D laser-scanning has proven to be an effective technology to conduct lightweight design. This paper introduces a point-based algorithm to simplify laser-scanning point cloud without any support of fitted surface. The intrinsic characteristic of laser-scanning data is investigated to produce a topological connectivity for adjacent points in scan-lines. We explore an automatic normal-vector estimation framework through the relationship between normal-vector and its adjacent geometric elements. To retain more points in high-curvature areas and fewer points in planar regions efficiently, the local normal-vector variance is adopted to determine subdivision-decision condition. The boundary points are detected and then preserved before non-uniform subdivision. A relevant simplification system based on our algorithm is developed. Many simplification cases are implemented to validate the effectiveness of our method and demonstrate the feasibility for automobile-bodies point cloud. The comparison with other point-based methods is also performed to illustrate the superiority of our method.
Keywords: point cloud; simplification; laser scanning; lightweight design; automobile body; hierarchical clustering; reverse engineering.
A mathematical model for vibration analysis of a parallel hybrid electric bus powertrain
by Wei Chen, Zhengwei Li, Yulong Lei, Sajad Saraygord Afshari, Yao Fu, Liguo Hou
Abstract: This paper presents a parallel hybrid electric bus equipped with an automated manual transmission (AMT) and a mathematical model of the hybrid powertrain is developed for vibration analysis. The powertrain dynamic model is established by a modular modelling approach. A detailed AMT dynamic model, considering gear time-varying meshing stiffness, shaft elastic deformation, and bearing elastic support, is incorporated into the powertrain dynamic model. The damping and gyroscopic effects of the gear-rotor in the AMT are considered as well. The AMT dynamic model is validated by experimental data from the time and frequency domain comparisons. Finally, the parameter analysis of the dual-mass flywheel (DMF) is used to illustrate how to use the proposed powertrain dynamic model for vibration reduction. The influence of the DMF parameters on vibration responses of the system with varying engine rotation speed is investigated. This study provides a basis for further vibration control of the hybrid powertrain during the engine driving mode.
Keywords: hybrid electric bus; powertrain; dynamic modelling; vibration analysis; dual-mass flywheel.
Investigation on energy consumption of electric vehicle with micro gas turbine as a range-extender under various driving cycles
by Xiangbo Zhang, Fenzhu Ji, Farong Du, Shuiting Ding, Yu Zhou
Abstract: The Micro Gas Turbine (MGT) offers an attractive option for range-extended electric vehicles (REEVs) to prolong the driving range. This research aims to investigate the energy consumption of MGT-based REEV under different driving cycles to evaluate the performance of the MGT-based range extender. As a core component, the performance of MGT with recuperator is analysed and simulated based on Brayton cycle. The steady-state and transient characteristics of the MGT model is verified through experiments. A model of the MGT-based REEV is established to access the energy consumption of EV under highway fuel economy cycle (HWY) and supplementary FTP driving cycle (US06). Results show that the MGT model has a high precision. The difference between simulation and experiment is smaller than 2% in power, and
Keywords: range-extended electric vehicle; micro gas turbine; energy consumption; driving cycles; simulation.
Lightweight design of a bodyinwhite structure using a hybrid optimisation approach
by Dengfeng Wang, Shenhua Li
Abstract: To achieve lightweight structure for a BIW (bodyinwhite), this study proposes a hybrid optimisation approach that integrates the subspace division of a BIW structure, relative sensitivity analysis, correlation analysis, NSGAII (nondominated sorting genetic algorithm II) combined with a RSM surrogate model, and design of experiments combined with ETOPSIS (entropy weighttechnique for ordering preferences by similarity to ideal solution). The approach improves the optimisation efficiency and solves the problem of nonlinear crashworthiness optimisation. The decoupling of the linear basic performance and nonlinear collision safety performance of a BIW are achieved. According to the type of performance response, design variables are screened, and three subspace structures of the BIW are optimised. Optimisation results indicate that the mass of the BIW structure is reduced by 17.0 kg. The performance quotas of the BIW are within the specified design baseline range. Therefore, the proposed approach can be effectively applied to the lightweight design of a BIW structure.
Keywords: BIW; body–in–white; lightweight design; crashworthiness optimisation; relative sensitivity analysis; correlation analysis; NSGA–II; design of experiments; TOPSIS.
Research on vehicle window buffeting mechanism and noise control
by Qiliang Wang, Xin Chen, Yingchao Zhang, Qingqing Guan, Mingyang Song
Abstract: For a moving car, buffeting noise is generated when a window is opened alone, which seriously affects the comfort of passengers. In particular, there is still no effective control method for side window buffeting, so it is very important to study the buffeting mechanism and characteristics for noise control. First, this paper analyses the pressure change law during the shear vortex shedding process through simulation, and explores the Helmholtz resonance characteristics of the passenger cabin, so as to reveal the causes of the buffeting phenomenon. Secondly, wind tunnel tests are used to study the effects on buffeting of vehicle speed, window opening size and other factors, and the differences in buffeting characteristics between sunroof and side windows are compared, then the reasons for buffeting changes are analysed through simulation. Finally, the passive control and active control are discussed, which have reference significance for the control of vehicle window buffeting.
Keywords: vehicle window buffeting; flow mechanism; buffeting characteristics; noise control.
Multi-objective optimisation of automobile sound package with non-smooth surface based on grey theory and particle swarm optimisation
by Shuming Chen, Zhenyu Zhou, Jixiu Zhang
Abstract: This paper studies a multi-objective optimisation design of the sound package with non-smooth surface, for enhancing the acoustic performance and reducing the material weight. In order to perform the acoustic simulation of the sound package with non-smooth surface, an effective finite element analysis procedure was used in this work. The sound absorption performances of porous materials were predicted by using two-microphone transfer function method combined with finite element method (FEM). Smooth surface and triangular surface were chosen for analysis to compare sound absorption performances of sound packages. Moreover, an orthogonal experiment was designed to compare sound absorption performance and material mass among different sound package with different surface parameters and thickness. Thus, the multi-objective design was converted into a single objective with grey correlation degree. Furthermore, the average grey correlation degree of parameter variables was analysed. On this basis, the optimal combination was selected by using particle swarm optimisation algorithm. From the optimization data, triangular surface sound package material with the optimal surface parameters and thickness was numerically simulated applying finite element method. The simulation result shows that sound absorption performance was improved while the material mass decreased.
Keywords: sound absorption coefficient; optimisation; sound package; grey relational analysis.
Unified AHP-TOPSIS and DEA technique for the adoption and performance evaluation of green transportation alternatives in India
by Neha Gupta, Chand P. Saini, Amit Dangi, Tanwir Akhtar
Abstract: We cannot think of todays age without transportation. Also, global warming, environmental degradation, adverse health implications, and greenhouse gas emission are some of the problems in the existing transportation mode. The solution to these problems is the shift towards green transportation, which means shifting to such transportation practices or vehicles that do not have any negative impact on the immediate environment and are eco-friendly. Therefore, the use of electric vehicles (EVs) can shift India towards sustainable transportation or eco-friendly transportation. EVs are different from petrol vehicles on distinct properties. EVs have zero tail-pipe outflows, less noise, and low running expense contrasted with the internal combustion engines. This paper adds to the existing information by undertaking a multicriteria analysis for ranking and performance measures of EVs based on the rating by two stakeholder groups, electric vehicle dealers and electric vehicle users. In this paper, the criteria for the selection of EVs are identified from the literature and personal interviews. This paper uses the combination of AHP, TOPSIS, and DEA techniques to rank the various types of EV and measure the performance of eight electric and eight hybrid electric cars that exist in India.
Keywords: green transportation; electric vehicles; multicriteria analysis; AHP; TOPSIS; DEA.
Multi-disciplinary design optimisation considered fluid-structure interaction and life prediction applied in the lightweight carbody structure
by Bingrong Miao, Yaoxiang Luo, Qiming Peng, Chuanying Jiang, Zhongkun Yang
Abstract: Multi-disciplinary design optimisation based on rigid-flexible multi-body system is presented to solve the multi-object design optimisation problems of lightweight carbody structures by considering the fluid-structure interactions at different typical load cases. A mathematical model is developed to simulate structure interactions based on the theory of finite elements. The model is integrated with a multi-object optimisation approach that uses the non-sort genetic algorithm method. The multi-body system was used to understand complex vehicle system dynamics performance and obtain the structure load time histories. Through performing structural quasi-static stress analysis method, the structure dynamic stress/strain histories were obtained for fatigue life evaluation. The results demonstrate the effectiveness of the proposed approach in simultaneously considering the structural vibration and the aerodynamic pressure at several vehicle speeds by proper lightweight design. This method has the advantage that it can be used to understand the interaction mechanism between the vehicle dynamics characteristics and lightweight structural fatigue damage.
Keywords: multi-disciplinary design optimisation; multi-body system; lightweight design; finite element method; railway.
Establishment of mathematical model of inner tooth profile curve and simulation based on dual phase silent chain
by Yabing Cheng, Xiaomin Chen, Yang Li, Xinyue Li, Luxiang Chen, Jiaxing Niu
Abstract: According to the meshing principle of chain drive, the formula of coordination transform and pitch variation principle of dual phase Hy-Vo silent chain, the formula of the inner tooth profile curve of dual phase Hy-Vo silent chain is built. The mathematical model of the inner tooth profile curve of the new chain plate is established. The dynamic model of quasi-conjugate meshing between the working chain plate of silent chain and the involute sprocket is established. The new type silent chain system with inner tooth profile is compared with the previous one. The simulation results show that the new type Hy-Vo silent chain system has less fluctuation, less change of angle velocity of chain plate and moves more smoothly. The rationale of the mathematical model and the superiority of the dynamic model of the new type Hy-Vo silent chain system with inner tooth profile are verified.
Keywords: chain transmission; dual phase Hy-Vo silent chain; inner tooth profile curve; fluctuation quantity; multi-variation.
Sound quality evaluation of pure electric vehicle with subjective and objective unified evaluation method
by Jing Cheng
Abstract: The focal points for sound quality of a pure electric vehicle (PEV) usually depend on its operating condition. Therefore, a subjective and objective unified evaluation model for sound quality evaluation of PEV based on operating condition is presented. With acoustic test results, a hierarchical comparison method (HCM) is proposed for their subjective acoustic quality evaluation. Four psychoacoustic parameters and one evaluation index of pure tonal noise are used to evaluate the noise samples. A noise sample library based on operating mode is established, and the sound quality evaluation models based on the back propagation neural network (BPNN) and the support vector machine (SVM) were established and compared. The results show that the evaluation model has high accuracy, and when the sample size is insufficient, the accuracy of SVM model is better than the BPNN model.
Keywords: PEV; sound quality; HCM; subjective and objective unified model; multiple operating conditions; BPNN; SVM.
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: Vehicle Safety Design and Assessment
Design and development of quad bike chassis frame
by Surajkumar Kumbhar
Abstract: Safety is the most critical concern about a quad bike, especially one designed for wider varieties of terrains and that offers negligible protection to the rider. A higher number of deaths and injuries have been reported to all-terrain vehicles (ATV) according to the National Trauma Data Bank. This inspires our team to design a quad bike for the safety of passengers. In this work, a quad bike chassis frame is designed and developed for the Quad Bike Design Challenge (QBDC). The development is based on the principles of similitude, personal experience, actual test track data, and all previous history to optimise the design of the quad bike chassis frame. Structural analysis of the designed frame is carried out using FEA, and modal analysis is performed through FFT. Results indicate that the developed chassis frame is rigid, lightweight, and safer than the old frame. This original contribution shows a systematic way of design for the safety of quad bike occupants.
Keywords: quad bike; chassis frame; finite element analysis; modal analysis.
Fault diagnosis and failure analysis of motor controller by the approach of Bayesian inference
by Xiong Shu, Yingfu Guo, Huan Yang, Hongguang Zhou, Kexiang Wei, Sudong He
Abstract: Electric vehicles are growing in popularity, it is deemed that they will replace petrol and diesel vehicles in the near future. However, the failure analysis and fault diagnosis of the motor controller is still a matter of concern today. In order to solve the problems of multiple fault decoupling, location and diagnosis in motor controller hardware system of electric vehicle, a fault diagnosis method of motor controller based on Bayesian network is proposed. On the basis of decomposing the hardware structure of the motor controller, the fault categories of the motor controller are classified, firstly; then the hardware fault tree of the motor controller is established. Finally, the fault diagnosis model of the motor controller hardware system is established by converting the fault tree into a Bayesian network. In terms of data quantification, the method of leak noisy-or node was introduced to reduce the demand of conditional sample data. In order to verify the feasibility of the fault diagnosis model for motor controller hardware, a case study is conducted in this paper, and the results show the effectiveness of the method.
Keywords: motor controller; electric vehicle; faults diagnosis; Bayesian network; fault tree analysis.
Reliability evaluation method of vehicle acceleration sensor based on vector control
by Hongbo Liang
Abstract: In order to overcome the problem of large error in the existing reliability evaluation method of vehicle acceleration sensors, a reliability evaluation method of vehicle acceleration sensors based on vector control is proposed. This method selects the reliability evaluation index of an acceleration sensor based on AHP, calculates the comprehensive weight value of the evaluation index, constructs the vector control model with the weight value, solves the reliability evaluation value of acceleration sensor, and judges the reliability level, so as to realise the reliability evaluation of the sensor. The experimental results show that the failure limit of the acceleration sensor is determined to be 2.0
Keywords: vector control; acceleration sensor; reliability; evaluation;.
Speed control of vehicle automatic driving system based on 5G vehicle network
by Minglei Song, Ai-zeng Li, Li-hua Liu
Abstract: In order to solve the problem of low speed control accuracy and long control time in the traditional vehicle speed control system, a speed control method of vehicle automatic driving system based on 5G network is proposed. The 5G Internet of vehicles technology is used to collect the motion data of vehicle automatic driving, and the vehicle motion model is constructed by least squares method. The speed control model of vehicle autopilot system is built, the minimum speed algorithm is used to solve the speed governing model of the vehicle automatic driving system, and the optimal trajectory of speed control for vehicle automatic driving system is obtained, and the speed control of vehicle automatic driving system is realised. The experimental results show that the speed control method in this paper can effectively improve the speed control accuracy of the system, up to about 99%, and that the speed of speed regulation is fast.
Keywords: 5G vehicle interconnection; vehicle automatic driving system; speed control; vehicle motion model; least squares algorithm; minimum value algorithm.
Research on vehicles collision avoidance warning system based on trajectory data mining
by Ying Li
Abstract: In order to overcome the problems of large error of safe distance judgement and poor braking stability in traditional vehicle anti-collision warning systems, this paper proposes a vehicle anti-collision warning system based on trajectory data mining. The hardware design of the system includes vehicle anti-collision warning controller, vehicle trajectory data mining sensor and vehicle anti-collision pre-warning program, which can accurately collect vehicle trajectory data. Based on the above data acquisition results, the vehicle trajectory is deeply mined and cluster analysed, and the mathematical model of critical safe distance of vehicle is constructed. The calculation principle of vehicle collision probability is used to calculate the vehicle collision probability and realise vehicle collision warning. The experimental results show that the braking stability is close to 1, which can ensure the safety of the vehicle.
Keywords: trajectory data mining; vehicle’s collision avoidance; safe distance; collision probability;.
A tracking control method for collision avoidance trajectory of autonomous vehicle based on multi-constraint MPC
by Zhiyong Jing, Wei Huang, Huan Ma
Abstract: In order to overcome the problems of low control accuracy and control efficiency of the traditional vehicle collision avoidance trajectory tracking control method, this paper proposes a multi-constraint MPC-based automatic driving vehicle collision avoidance trajectory tracking control method. The vehicle dynamics model and tyre dynamics model are constructed, and the relationship between tyre slip angle and force is analysed from three degrees of freedom directions. The road adhesion coefficient of the tyre is calculated, and the relationship between adhesion coefficient and tyre lateral force is studied. Combined with the dynamic model and the analysis results, a multi-constraint MPC model is constructed, and the model is solved by empc to realise the trajectory tracking control of an automatic driving vehicle. The experimental results show that the proposed method can accurately predict the vehicle lateral position and yaw angle, and the control accuracy is high.
Keywords: multi-constraint MPC; automatic driving; vehicle collision avoidance; trajectory tracking; dynamic model.
Research on feature extraction of vehicle abnormal driving behaviour based on 5G internet of vehicles
by Wei Yu
Abstract: In order to overcome the problems of high response time delay and low accuracy of traditional vehicle abnormal driving behaviour feature extraction methods, this paper proposes a 5G car networking-based vehicle abnormal driving behaviour feature extraction method. This method uses the infrastructure and sensor equipment of the perception execution layer of the 5G internet of vehicles to collect vehicle information, and selects the Internet Protocol Version 6 communication protocol of the network transmission and control layer for data transmission. Based on the data received by the integrated application layer, the Riemannian manifold method is used to extract the characteristics of abnormal driving behaviour, such as emergency acceleration, emergency deceleration, speeding, and frequent lane changes. Experimental results show that the extraction accuracy of this method is as high as 98%, which can effectively extract the characteristics of abnormal driving behaviour, and the response delay during data transmission is less than 80 ms.
Keywords: 5G; internet of vehicles; abnormal driving behaviour; feature extraction.
Collision-warning system integrated with merging behaviour prediction model based on multi-sensor fusion
by Guoyan Xu, Yiwei Xiong, Huan Niu, Guizhen Yu, Bin Zhou
Abstract: One of the most dangerous situations on a road is that drivers choose to merge into traffic without warning. This paper presents a real-time collision warning system in merging scenario, and our approach mainly focuses on the forward vehicle in a different lane. First, a multi-sensor is used to detect the distance and speed information of forward vehicles. Based on the detection result, a neural network is designed to predict whether they are going to change lane or not. The prediction model correctly classifies 92% of merging behaviour in our test dataset. Then, a collision warning algorithm is proposed to cope with different merging manoeuvres. The algorithm was tested in a real road on our embedded platform and the results show that the system can effectively alert drivers to brake when collision threats are posed.
Keywords: collision warning; multi-sensor; merging behaviour prediction; perception system; deep learning; convolution neural networks; object detection; lane detection; neural network.
Design and simulation of a pedestrian protection airbag using corpuscular particle method
by Reza Deabae, Javad Marzbanrad
Abstract: This research developed a methodology based on the Corpuscular Particle Method (CPM) for assessing the effectiveness of a Pedestrian Protection Airbag (PPA). Although current studies are attempting to determine the efficiency of pedestrian protection systems, so far no research has been conducted employing the CPM for examining the influence of inflator gas flow on the performance of the PPA and head injuries. The method is divided into two main steps. At the first step, validated models of a vehicle and an adult headform were chosen, and the EuroNCAP standard adult pedestrian headform impact test was simulated for different points at the bottom of the windshield and on A-pillars. The simulation results were assessed against available experimental test results and recorded to check the effect of PPA at the next stage. Then, the headform impact simulation was conducted while a PPA was installed on the vehicle. The airbag deployment was simulated using CPM, and the headform impacted the PPA at the same points as step one. Simulation results were evaluated against available experimental test data and compared with those without the PPA test from the first step. The results of this research can be used to enhance the production of various pedestrian protection technologies for vehicles. Simulation results prove that using a pedestrian protection airbag can reduce head injuries by up to 90% near A-pillars, which are the most dangerous zones for the pedestrians heads. Study results suggest that CPM is able to precisely capture the realistic kinematics of airbag deployment, particularly during the early deployment phase. Furthermore, CPM rationally estimates these parameters at the extremely complex phases of the airbag unfolding.
Keywords: pedestrian safety; pedestrian airbag; corpuscular particle method; vehicle-to-pedestrian crash; headform; crash simulation; passive safety.
Translation of SysML diagram into mathematical Petri net model for quantitative reliability analysis of airbag system
by Ankur Maurya, Divya Kumar
Abstract: Airbag systems have become an indispensable safety device to assure the physical welfare of drivers and passengers. The proper functioning of the airbag is crucial as it is the endmost hope of a passengers life in the case of a vehicle collision. Airbag systems are safety-critical systems (SCS) that are developed to avoid catastrophic consequences, such as injury, death, or environmental damage. Hence, reliability and failure analysis of such systems is of utmost importance during design. There are numerous methods existing in literature for safety and reliability analysis of safety-critical airbag systems but these methods are qualitative in nature, which are based on pre-assumed transition probability and only suitable for stakeholders having good technical knowledge. There remain high possibilities to miss out important information while designing the system. The requirement analysis and quantitative reliability analysis of airbag system during design phase are the main aim of this paper. This is done by translating SysML diagram into a Petri Net (PN) model and computing non-assumed transition probabilities of the system in real-time scenarios by identifying the possible number of events that can trigger failure in airbag systems. The proposed method in this paper captures the dynamic behaviour of the system. The result has been verified using ASIL ISO2626 safety standards and compared for different vehicle manufacturers. The most reliable vehicle models are BMW and Chrysler with unreliability of 0.07%.
Keywords: airbag systems; system reliability; requirement analysis.
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.
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.