Research On Electro-hydraulic Compound Stability Control Of Distributed Drive Vehicles

With the rapid development of automobile industry,energy consumption?pollution and transportation safety become serious.The distributed drive electric vehicle not only can cope with those above problems,but also become focused research for scholars at home and abroad with significant advantages in dynamic control.The distributed drive electric vehicle as a study object in this paper,and distributed drive electric vehicle dynamics control mechanism and stability control strategy are studied.The main researches are as follows:Firstly,based multi-body dynamic model of vehicle is developed in CarSim and linear two freedom degrees vehicle dynamics control model is established in Matlab/Simulink based on the study of vehicle dynamics control.After that,Under the typical condition,CarSim and MATLAB/Simulink joint simulation method is adpoted to validate both multi body dynamic model and vehicle dynamics control model.Secondly,the electrohydraulic composite stability control system is developed control the stability of vehicle body.The control system is implemented by a hierarchical control structure.The upper level motion controller includes reference model,speed following module and yaw tracking module.The reference model calculates the require vehicle motion programming mainly based on road adhesion condition,vehicle movement state and driver steering input;The speed following module calculates the required longitudinal force for speed following based on the ideal speed and actual speed determined by the throttle position;The yaw tracking module calculate additional yaw moment by using fuzzy PI control.The lower level control distributor includes electro-hydraulic compound control module,motor torque control module and brake pressure control module.Electro-hydraulic compound control module calculates real-time control signals of motor and braker according to the state of driving vehicle;the motor torque control module calculate the optimal torque distribution of four wheel hub motors according to both the control signals of Electro-hydraulic compound control module and required longitudinal force from speed following module.The brake pressure control module distributes optimal brake pressure based on control signals from Electro-hydraulic compound control module.Finally,both CarSim and MATLAB/Simulink joint simulation platform and hardware in loop experiment platform are developed to validate the performance of proposed control system.Under Sinusoidal amplification condition and sinusoidal delay condition,both simulation and experiment results show that The designed control system can make full use of motor and hydraulic pressure,especially under the limit condition,compared with electric control,the stability of the vehicle of proposed control system is significant improved.