International Journal of Vehicle Performance (22 papers in press)
Optimization of the energy efficiency of a hybrid vehicle powertrain
by Ali Salah Mourad, Benhadj Braiek Naceur
Abstract: Nowadays fossil fuels are the main source of energy in all areas. This energy has become less abundant, more expensive and much more polluting. To minimize fuel consumption, automakers are committed to develop new more efficient engine motorization system architectures. The substitution of the conventional thermal engine by a hybrid powertrain provides an additional degree of freedom to manage the energy flow between an electrical branch and a thermal branch to consume less fuel. Note that parallel architecture offers the best compromise between simplicity of design and energy efficiency, relative to other architectures and in particular serial architecture and mixed architecture. The optimization of fuel consumption relative to a known driving history such as (NEDC) does not solve the problem of optimization of fuel consumption when driving conditions are unknown in advance (actual operation of a vehicle). This work treats the energy modelling of a parallel architecture powertrain and proposes a new algorithm for optimizing fuel consumption, which is independent of the route taken by the vehicle. For this goal, we start by designing two energy models that express the instantaneous overall efficiency of the vehicle powertrain. Next, we develop the fuel optimization algorithm. Compared to the internal combustion engine of a conventional vehicle, the hybrid vehicle of parallel architecture shows, via simulations, a significant energy efficiency gain.
Keywords: Parallel hybrid vehicle; Powertrain; Energy management; optimal control strategy; instantaneous optimization of energy flow.
Evaluation of Worldwide Harmonized Light Vehicles Test Procedure for Electric Vehicles using Simulation
by Jia Xian Teoh, Chew Kuewwai
Abstract: With the introduction of the Worldwide Harmonized Light Vehicle Test, an all-new drive cycle proposed by UNECE, is being set to standardize the global drive cycle testing procedure in determining emission compliance and energy and fuel consumption. This paper aims to evaluate the performance and the effect of the new driving cycle on different electric vehicles, compared with other commonly used regulatory drive cycles such as NEDC, FTP 75 and JC08. Using Matlab ADVISOR simulation, different vehicles namely, a hatchback of Nissan Leaf 2016, a sedan of Tesla Model S 60 and a low power electric vehicle of Mahindra E2O Plus have been simulated and investigated. Among the various driving cycles, the Worldwide Harmonized Light Vehicles Test Procedure, WLTP Test Cycle consumes the highest energy per unit distance to decently sized vehicles. This is consistent with the objectives of the new driving cycle in obtaining more realistic results. Nevertheless, the low powered electric vehicle is found to perform differently in the WLTP Test Cycle. As the performance of lower powered motor is limited, the strategic low-speed operation of the vehicle during the drive cycle can result in higher power consumption pattern. The paper also encompasses a method to simplify the complex modelling of the vehicle for the drive cycles simulation, while maintaining sufficient accuracy in its final emission results.
Keywords: Worldwide Harmonized Light Vehicles Test Procedure (WLTP); Driving Cycle Standards; Electric Vehicle; Vehicle Test Procedures; ADVISOR.
Load torque estimation for an automotive electric rear axle drive by means of virtual sensing using Kalman filtering
by Robert Kalcher, Katrin Ellermann, Gerald Kelz
Abstract: Load torque signal information in hybrid or battery electric vehicles would be beneficial for control applications, extended diagnosis or load spectrum acquisition. Due to the high cost of the sensor equipment and because of the inaccuracies of state-of-the-art estimation methods, however, there is currently a lack of accurate load torque signals available in series production vehicles. In response to this, this work presents a novel model-based load torque estimation method using Kalman filtering for an electric rear axle drive. The method implements virtual sensing by using measured twist motions of the electric rear axle drive housing and appropriate simulation models within a reduced-order unscented Kalman filter. The proposed method is numerically validated with help of sophisticated multibody simulation models, where influences of hysteresis, torque dynamics, road excitations and several driving manoeuvres such as acceleration and braking are analysed.
Keywords: load torque estimation; electric rear axle drive; virtual sensing; Kalman filtering; unscented Kalman filter; UKF; reduced-order unscented Kalman filter; ROUKF; hybrid electric vehicles; HEV; battery electric vehicles; BEV; multi-body simulations; MBS; vehicle systems modelling.
Deep reinforcement learning-based energy management strategy for hybrid electric vehicles
by Shiyi Zhang, Jiaxin Chen, Bangbei Tang, Xiaolin Tang
Abstract: In recent years, with the development of new energy vehicle industry, the development potential of hybrid electric vehicles (HEVs) is increasing. As one of the key technologies, energy management strategy (EMS) has always been a hot research area for hybrid electric vehicles. This paper proposed a Deep Q-Network (DQN) based EMS for a parallel HEV. Simulation results after training show that, compared with the EMS based on dynamic programming (DP), the DQN-based EMS can achieve 8.38% of the fuel consumption gap while the calculation time is only 12.5%. By the computational advantage of neural network, the average output time of an action in each state is 1ms, which has the potential for real-time applications. Since the final EMS is parameterized and fitted by deep neural networks of deep learning, it is necessary to find further methods for the actual experimental scheme instead of simulation in the future.
Keywords: Hybrid electric vehicle; learning-based energy management strategy; deep reinforcement learning.
Special Issue on: Multibody System Algorithms in Vehicle Dynamics and Virtual Prototyping
Simulation and Experiments on Three-wheeled Vehicle on Different Tracks
by G.S.G. Ravikanth, Sujatha C
Abstract: Three - wheeled vehicles are used both for public and private transport in most of the Asian and African countries. Ride comfort is very important for these small-sized transport vehicles. A 6 degrees of freedom (DOF) mathematical model of a three wheeled vehicle is developed for predicting its ride behavior. Simulations are carried out on this model and responses of the sprung and unsprung masses are found on different tracks like (i) Half circular bump and (ii) trapezoidal. Sprung mass and unsprung mass accelerations are compared with experimental results and discrepancies between simulation and experiments are found. The discrepancy is mainly due to the difference between the analytical input given to the vehicle model (actual road profile) and the corresponding measured input. In order to bridge this gap, the paths traced by the tyre for the two different profiles are obtained as 2D layouts and differences between the analytical road input and the actual input traced by the tyre are found. The road input to the vehicle model is updated with the path traced by the tyre. The simulated responses of the 6 DOF model are validated on the two different tracks using the paths traced by the tyres as input and good correlation is found between experimental results and simulations.
Keywords: Three wheeler; Ride comfort; Terrain modeling; Tyre path; Mathematical modeling.
A dynamic model of a Cardan joint to evaluate the effect of elasticity and manufacturing errors
by Marco Cirelli, Valerio Rossi, Pier Paolo Valentini, Ettore Pennestrì
Abstract: Cardan joint is a key component in many mechanical applications. Due to the redundancy of kinematic constraints, the accurate determination of reaction forces and the assessment of dynamic effects caused by joint tolerances are very challenging tasks. This paper presents a computer-aided multibody modelling approach for the simulation of a Cardan joint with manufacturing errors. During the modeling phase, the elasticity of flexible bodies is lumpedrnand the joint compliance is taken into account using concentrated non-rnlinear spring elements. Numerical examples have been developed and discussed in order to test the feasibility of the proposed methodology.
Keywords: Cardan joint; universal joint; flexibility; tolerance; elasticity; elastic coupling.
Model-Based Simulation of Dynamic Behaviour of Electric Powertrains and Their Limitation Induced by Battery Current Saturation
by Dario Mangoni, Alessandro Soldati
Abstract: The wide-spread e-mobility revolution is asking for new software solutions capable of providing meaningful information not only for the mechanical part of the vehicle architecture, as in the past, but also for novel electric and hybrid driveline components. The complexity of the system is due to many factors, mainly but not only the different coexisting time scales on the basis of which the two different sub-parts, the mechanical and the electrical ones, operate.
The objective of the paper is to provide a lightweight model for a fully electric vehicle powertrain, trying to assess the current constraints imposed by the battery to the whole driveline, and able to reflect this limitation throughout the transmission line, down to the electric motor and thus to the performance of the full vehicle. The model is suitable for real-time performances thanks to the effective computation of the powertrain via analytical solutions. Moreover, the whole system has been modelled following a Model-Based approach in Modelica language and is made part of the Altair Activate Car Real-Time library, in which both the electrical and mechanical parts integrate smoothly.
Keywords: battery; electric vehicle; model-based; Modelica.
Dynamic behaviour modelling of an Internal Combustion Engine Water Pump Transmission Belt Drive
by Gaetano Sequenzia, Michele Calabretta, Ignazio Assenza, Salvatore Massimo Oliveri
Abstract: Belt drives are commonly used in various types of transmissions to link two or more rotating shafts. In order to transmit the motion, an effective grip on the pulley has to be set by imposing a pre-load on the belt. Moreover, the dynamic of the system is strongly affected by the geometrical and inertial properties but also by the imposed belt tension force as a functional parameter affecting the vibration characteristics. In the present work it is presented an integrated methodology, experimental and numerical, to determine the dynamic behavior of a water pump drive in a high-performance internal combustion engine.
Keywords: Belt; Internal Combustion Engine; natural frequency; vibration modes.
Wheelrail wear simulation and rail cant optimisation based on railway vehicle dynamics
by Wei Li, Pu Wang, Shuguo Wang, Daolin Si
Abstract: A numerical prediction model for the wheelrail wear development on heavy-haul railway is established herein, and a corresponding programme is written using MATLAB. Using Archards material wear theory, wear distributions in the wheelrail contact patch and along the rail profile are evaluated via vehicletrack dynamics simulation and wheelrail rolling contact analysis. In the vehicle dynamics model, various structural components and complex nonlinear interactions between components are precisely simulated to guarantee consistency with reality. The established model is employed to study the influences of rail cant on the wheel-rail wear distribution and development. The following two main conclusions are drawn. On straight railway section, the wheelrail contact region and wear distribution become unreasonable when the rail cant exceeds 1/20. On curved section, the influences of rail cant on the wear of the inner and outer rails are different. The changes of rail cant also obviously impact the changing rules of wear with the vehicle speed. A rail cant of 1/30 is recommended for the curved section of heavy-haul railway.
Keywords: heavy haul railway; vehicle-track dynamics; wheel–rail contact; wear; numerical simulation; rail cant; optimisation.
Study the Dynamic behaviour of seven DOF of full car model with semi-active suspension system
by Hemanth Krishna, Shamanth Vasanth, Devaraj Sonnappa, Hemanta Kumar, Gangadharan KV
Abstract: This paper presents an investigation on the ride comfort and road-holding performance of a vehicle equipped with the semi-active suspension system. The full car semi-active suspension model with 7 degrees of Freedom (7 DOF) system is adopted for the study and a fuzzy-logic control strategy is considered for minimizing the effect of road disturbance on vehicle performance. The responses of a vehicle have been analyzed under the Indian average random road profile (ISO8608) against the conventional passive suspension system. The performance of the semi-active suspension system is evaluated by heave, roll and pitch acceleration of the vehicle body around its center of gravity. The performance of a vehicle with the semi-active suspension system has been compared with the response conventional passive suspension system. The result specifies that, the semi-active suspension system with a Fuzzy-logic controller reduces around 43 % of vibration amplitude at the resonance frequency of vehicle than the passive suspension system.
Keywords: Full car; MR damper; Modified Bouc-wen; NSGA-II; optimization; fuzzy logic and Indian average road.
Research on Hierarchical Control Strategy of Electromagnetic Active Mounting System
by Zheming Chen, Heng Wang, Chenguang Lai
Abstract: In order to improve the vibration isolation performance of the automotive powertrain mounting system, a hierarchical control strategy is proposed according to the structural characteristics of the electromagnetic active mounting system and the influence of the dynamic characteristics of the actuator on the system control accuracy. Based on the analysis of the active mounting system 3 degree-of-freedom (DOF) 1/4 vehicle, the mathematical model of the mounting system and the electromagnetic actuator control circuit is derived. Guided by hierarchical control strategy, upper and lower controllers are designed for mount part of the active mounting system and actuator circuit respectively. The upper mounting controller is under LQR control with strong adaptability, fine robustness and easy implementation, and the weight coefficient of its performance index is optimized by genetic algorithm. The lower part of the actuator circuit is under simple and practical PID control and its parameters are optimized through particle swarm optimization algorithm. To verify the effectiveness of the control strategy, two typical working conditions are set for simulation research with the system input of the joint excitation of the engine and pavement. The results show that compared with the active mounting system under conventional control, the system designed according to the hierarchical control strategy can control different working conditions of the vehicle more precisely, which not only improves the vibration isolation performance of the powertrain mounting system to a certain extent, but also renders a better robustness and force tracking property.
Keywords: Automotive engineering; powertrain; electromagnetic actuator; active mount; LQR control; genetic algorithm; PID control; particle swarm optimization; hierarchical control; simulation analysis.
Performance evaluation of different centrifugal pendulum morphologies through multibody dynamics simulation
by Marco Cirelli, Ettore Pennestrì, Pier Paolo Valentini, Romualdo Paga
Abstract: This paper aims to evaluate the effectiveness of the centrifugal pendulum applied to an internal combustion engine as a vibration damper. In particular, a specific design strategy, based on an energy equivalence, is analyzed using a series of multibody simulations. A simplified model is initially discussed and different solution morphologies simulated. The present solution is based on the roller-in-slot centrifugal pendulum, designed to have the same kinematic behavior of lumped mass models. The reasons why the centrifugal pendulum has had in recent years numerous applications are evidenced, together with a discussion of some design strategies. The main characteristics and requirements of this vibration damper are presented. Simulation strategy is subsequently showed, with a description of all bodies, forces, and parameters used in the different systems analyzed. To assess the effectiveness of the design strategy, a comparison among the simulation results of the different solutions is offered.
Keywords: Centrifugal Pendulum; Vibration Absorber; Multibody Dynamics; Trapezoidal pendulum; Contact simulation; Equivalent mechanism;.
Out-of-Plane Flexible Ring Tire Model Development and Validation
by Bin Li, Xiaobo Yang, James Yang
Abstract: In this paper, a novel out-of-plane flexible ring tire model is developed, which is an extension of our previously proposed in-plane flexible ring tire model. The tire model includes a rigid rim, certain number of discretized belt points, and numerous tread blocks attached between the belt and the ground. In this model, the tire is divided into several layers, with each layer similar as the in-plane tire model. The parameters in the out-of-plane tire model are divided into in-plane tire parameters and out-of-plane tire parameters. The values of the in-plane tire parameters are borrowed directly from the in-plane tire model, and the out-of-plane tire parameters are identified based on a certain out-of-plane cleat test. Once the parameters are determined, various ADAMS
Keywords: Out-of-plane flexible ring tire model; tire model parameterization; tire cleat tests; tire dynamics; and tire model validation.
Special Issue on: Recent Advances in Energy-efficient Research for Vehicle Performance Improvement
A new model predictive torque control strategy for Permanent Magnet Synchronous Hub Motor of EVs
by Long Chen, Hao Xu, Xiaodong Sun
Abstract: This paper presents an optimal control strategy for a permanent magnet synchronous hub motor (PMSHM) of EVs drive using three voltage vectors. First, in order to simultaneously control torque and flux excellently, three voltage vectors including two active vectors and one zero voltage vector are selected. Second, the duration of the three voltage vectors in one period is calculated by the principle of simultaneous deadbeat control of torque and flux. Moreover, the cost function which eliminates the weight coefficient is proposed to reduce the amount of calculation. Finally, the proposed method is compared with the one- and two-vector-based model predictive torque control (MPTC) methods both in simulation and experiment. It is found that the proposed three-vector-based MPTC can obtain better performance such as smaller torque ripple and current total harmonic distortion (THD) both in steady and dynamic state.
Keywords: Model predictive torque control (MPTC); permanent magnet synchronous hub motor (PMSHM); three voltage vectors.
Study on Comprehensive Performance of Ni-MH Power Battery Used in HEV at Different Temperatures
by Xiang Chen
Abstract: The safety concern of the lithium-ion battery drives major motor company such as Toyota to consider the nickel-hydrogen (Ni-MH) battery in their HEV (e.g. Prius). However, current understanding of the cycling life and SOC (State of Charge) estimate of Ni-MH battery in the HEV is still limited due to its insignificant market share. Thus, this study carries a comprehensive investigation on the influences of the key environmental and operating parameters on SOC and cycling life of the Ni-MH battery. Notably, the Ni-MH cells were tested through loading the actual road spectrum with different temperatures (25/35/45?) being used to identify the impacts based on the actual work condition. Other factors including discharge current and depth of discharge are operated at 15.5A and 10% by average, respectively. In addition, to obtain the battery polarization characteristics under different temperatures and SOCs, multiple trials have been performed to obtain the OCV (open circuit voltage)~SOC curves at different temperatures under the 1-C rate of charging/discharging. The investigation results show that the battery degradation is accelerated at the upper-end level of the operating temperature range. The capacity decay compared to initial capacity is increased by a slight 2.46% at 45?, which demonstrates an excellent cycling performance of the Ni-MH battery. The battery polarization effect is found to be correlated to the charging and discharging processes. The lower the temperature is, the greater the polarization effect can be observed as a more salient OCV difference presents between charging and discharging. The polarization effect almost disappeared after 3 hours resting according to the results in this study. In summary, this study presents a comprehensive factor analysis needed to achieve a reliable SOC estimate for the Ni-MH based HEV.
Keywords: Ni-MH battery; hybrid electric vehicle; polarization effect; Cycling life; SOC estimate.
Research on Modeling and Simulation of single-mode power split hybrid system
by Aihua Chu, Xiang Chen, Yinnan Yuan, Tong Zhang, Huijun Cheng, Wenran Geng
Abstract: Aiming at an optimized single-mode compound power split hybrid system, the main operating mode of the hybrid system and the torque control strategy were developed in this paper. LMS/AMESim was used to establish the plant model of the vehicle as well as the key components of the hybrid system, while the vehicle control model was established in Matlab/Simulink. Both control model and plant model were integrated in the same environment through co-simulation technology. In addition, the fuel economy of a certain SUV under the NEDC road spectrum was simulated by the co-simulation model, and the simulation results were compared with the experimental results on the auto chassis dynamometer. The results have shown that in the HEV operation mode, the electric energy consumption of the battery in experiment was 0.6241kWh well agreed with the value of 0.6220kWh through simulation, achieving only 0.33% deviation. Moreover other two key indicators, the SOC change and regenerative braking energy recovery, were found to be -4.8% and 694.90kJ, respectively, in the simulation. These results are strikingly compatible to the experimental values as well. The deviations are 0.7% and 3.8% respectively. The results demonstrated that the established simulation model is an accurate reflection of the physical reality under different road spectrum conditions. Application of the model can greatly reduce the difficulty of control strategy design and improve the efficiency of vehicle development.
Keywords: hybrid electric vehicle; power-split system; CHS2800; co-simulation; vehicle controller model; AMESim; MATLAB/Simulink.
The effect of peppermint odor on fatigue and vigilance in conditional automated vehicle
by Qiuyang Tang, Gang GUO, Meng Jin Zeng
Abstract: Drivers in conditionally automated vehicles have been found to become fatigued easier than manual drivers, and the risk of accidents increased due to the decrease in vigilance. Olfactory stimulation is a promising method to counterbalance fatigue and increase vigilance. However, little is known about the effect of peppermint odor on relieving fatigue and increasing vigilance during automated driving. Therefore, to better understand the effect of peppermint odor stimulation during automated driving, a driving simulator study with 34 participants was conducted. Subjective and objective variables were compared between two conditions: with peppermint odor and placebo (air). The results of the study indicated that the fatigue levels of drivers decreased after the release of peppermint odor. The indicators of reaction time and ocular variables supported that the drivers` vigilance increased during the peppermint stimulation. In conclusion, peppermint odor has a positive effect on relieving fatigue and increasing vigilance.
Keywords: Fatigue countermeasures; Peppermint odor; Driver vigilance; Eye movement.
Energy Management Optimal Strategy of FCHEV Based on The Radau Pseudospectral Method
by Yanwei Liu, Yuzhong Chen, Zhenye Li, Kegang Zhao
Abstract: Energy management of the fuel cell hybrid electric vehicle (FCHEV) is a significant study area with respect to improving FCHEVs dynamic and efficiency performance and durability. Radau Pseudospectral Method (RPM)-based optimal control of energy management of FCHEV is introduced to optimize the fuel cells lifetime by means of reducing its performance degradation. To utilize the RPM, both state variable and control variable are approximated by the global interpolation polynomial, and then differential equation of state variable is approximated by the derivative of interpolation polynomial. Accordingly, the optimal control problem is transformed into nonlinear problem to be solved. The fuel cells performance degradation which refers to fuel cells voltage decline is selected as objective function. The results of optimal control in NEDC show that battery with larger capacity is more beneficial than smaller one for reducing the fuel cells performance degradation, with the total time of large load change of the fuel cell reducing. The RPM is an effective way to optimize not only the fuel cells lifetime but other objectives to energy management.
Keywords: energy management; fuel cell vehicle; electric vehicle; Radau Pseudospectral Method; optimal strategy.
Control Strategy of Genetic algorithm for a Hybrid Electric Container Loader
by Jian Li, Hong Shu, Zhien Xu, Weizhou Huang
Abstract: Hybrid electric container loaders are used for cargo transportation in aviation airports, which have characteristics of relatively complicated operating conditions and large load changes. How to ensure that under various loads, battery state of charges (SOCs) and temperatures the loader runs in the high efficient zone, the SOC and temperature of battery are maintained within a reasonable range is an important issue that the control strategy needs to solve. A genetic algorithm is applied to optimize the control parameters of the hybrid loader. The optimal control parameters are the charging torque limit, the discharging torque limit, the generator charging torque, the motor discharging torque, the engine speed at high and low load, and the battery high SOC threshold. The optimization target is to take the minimum equivalent fuel consumption under loader cycle conditions, and maintain the battery SOC sustain or reach the optimal range. The optimal control parameters of the loader under multiple loads, battery temperatures and initial SOCs were optimized offline by using genetic algorithms. Finally, a multidimensional response surface model for control parameters was established by a response surface method. The simulation shows that under various loads, battery temperatures and initial SOCs, the fuel saving of the hybrid loader is significant, the battery maintains the charge sustain or reaches within the optimal range, the battery temperature rising is kept within a reasonable range, and the battery charge and discharge rate is controlled within 1C.The fuel consumption of the hybrid electric loader is reduced by more than 20% compared with the traditional loader under the full load conditions and the initial SOC in the range of 0.6-0.8.Compared with the original calculation model optimized by genetic algorithms and the dynamic programming control strategy, it was verified that the calculation accuracy and fuel saving significance of the response surface model for control parameters.
Keywords: Hybrid Electric Vehicles; Control Strategy; Genetic Algorithm; Response Surface.
Research on regenerative braking strategies for hybrid electric vehicle by co-simulation model
by Han Guo, Jianwu Zhang, Wenran Geng, Huijun Cheng, Haisheng Yu
Abstract: Regenerative braking is an important factor in improving hybrid electric vehicle fuel economy. This paper presents the simulation modelling of a power-split hybrid electric vehicle with different regenerative braking strategies. A co-simulation model is used to enhance the simulation capability for the hybrid vehicle performance and development of control strategy. AMESim is used to model the complex physical components including engine, transmission, motors, battery and hybrid vehicle, and the physical model is integrated with control model established by MATLAB/Simulink, which is required to operate the vehicle and the regenerative braking system through standard drive cycles. Simulation results show that a regenerative braking control strategy can recuperate significant amounts of energy. Vehicle fuel economy in EV and HEV modes is improved significantly by coupling the proposed regenerative braking strategy.
Keywords: hybrid electric vehicle; regenerative braking; energy management; AMESim; MATLAB/Simulink.
Potential and Challenges to improve vehicle energy efficiency via V2X: Literature Review
by Kai Yang, Yanjun Huang, Yechen Qin, Chuan Hu, Xiaolin Tang
Abstract: With the development of intelligent transportation system, V2X information offers great opportunities to promote the energy efficiency of vehicles. This paper systematically elaborates the state of art which focuses on improving the energy efficiency using the V2V (vehicle to vehicle), V2I (vehicle to infrastructure), V2N (vehicle to network) and V2G (vehicle to grid) technology. Firstly, V2V technology applied in energy management of single and vehicular platoon is investigated. Secondly, eco-driving for connected vehicles using V2I information is studied. Thirdly, the potential of enhancing the energy efficiency by the V2N communication between vehicles and network is analyzed as well. Fourthly, the utilization of V2G technology to increase the energy efficiency of smart grid is presented. Finally, the challenges are suggested to facilitate the application of V2X technology to the enhancement of energy efficiency.
Keywords: vehicle energy efficiency; V2X; V2V; V2I; V2N; V2G.
Special Issue on: Recent Advancements in Commercial Vehicle Roll Dynamics Studies
Active Trailer Braking Control for Car-Trailer Combination Based on Multi-objective Fuzzy Algorithm
by Pengwei Su, Xing Xu, Feng Wang, Bin Wang, Jie Mi
Abstract: In order to improve the braking stability and path following performance of trailer under steering and braking conditions, a differential braking control method is proposed. Considering the electromechanical coupling characteristic of electromagnetic brake, a 6-DOF car-trailer (CT) combination dynamics model is established. A hierarchical control frame is proposed, the upper controller determines the additional yaw moment based on multi-objective fuzzy (MOF) control algorithm with yaw rate and hinge angle as control objects. The lower braking force distribution controller is designed with the rules to determine left and right braking torque, the electromagnetic brake gets the corresponding current to realize differential brake. A joint simulating model with TruckSim and Simulink is built, the simulation results show that the control strategy proposed in this paper effectively improves the braking stability of trailer. Compared with no differential braking control, the yaw rate and lateral acceleration are reduced, the hinge angle is closer to the ideal target under MOF control. Finally, real CT test is put forward to verify the accuracy of the model and the effectiveness of the control strategy.
Keywords: car-trailer; differential braking; yaw rate; hinge angle; multi-objective fuzzy algorithm; braking force distribution controller.