Research On Control Strategy Of Steer-by-wire System Based On Dual-motor Structure

Steer-by-wire(SBW)system with dual-motor steering actuator is a new type of SBW system,the steering function of SBW system,and the fault tolerant redundancy function of any single motor and good steering response function can be realized by the dual-motor steering actuator's three-loop PID angle closed loop control strategy,dual-motor steering actuator synchronous control can improve the steering system implementation of precision and reduce “servo fight” and other negative effects,in addition,dual-motor anti-backlash control can reduce the negative effect of SBW system caused by backlash nonlinear factors.This paper is supported by the National Natural Science Young Fund Project named “method research on hierarchical fault tolerant control of multi agent steer-by-wire system”(No.51505179)and the National Natural Science Fund Project “Research on the control mechanism and evaluation method of the novel steering-by-wire system based on the driver's characteristics”(Number: 51575223).Based on the basic “angle following torque feedback” control strategy of SBW system,the steer-by-wire(SBW)system with dual-motor steering actuator's dual-motor steering actuator synchronous control based on differential negative feedback mode was developed,the steer-by-wire(SBW)system with dual-motor steering actuator's dual-motor steering actuator anti-backlash control based on applying variable bias current was developed as well,the co-simulation test platform and a real-time hardware in the loop test bench was used to verify the effectiveness of the proposed control strategy,In this paper,the following aspects were studied:(1)The SBW system and its control strategy and the SBW system with dual-motor steering actuator and its control strategy research status at home and abroad research were implemented,the research value of SBW system with dual-motor steering actuator's was proposed,current research process of dual-motor synchronous control and dual-motor anti-backlash control in other fields was investigated,the significance of the dual-motor synchronous control was illustrated and the necessity of the dual-motor anti-backlash control was proposed too.(2)The general modeling method of the co-simulation of SBW system with dual-motor steering actuator was introduced,and then the Simulink software was used to establish the model of SBW system and the model of SBW system's “angle following torque feedback” control strategy,the Car Sim software was used to establish the vehicle model,the accuracy of co-simulation test platform was verified and compared,which lays a foundation for the development of subsequent control strategy.(3)Based on the control strategy of the SBW system proposed in this paper,the non synchronous factors of dual-motor drive system was analyzed,the dual-motor synchronous control strategy based on differential negative feedback was developed,and through simulation the considering and un-considering dual-motor's synchronous control contrast were compared under the steer-by-wire(SBW)system with dual-motor steering actuator's different structure parameters,load disturbance,different parameters of dual-motor three ring PID control and different factors of four kinds of factors;the steer-by-wire(SBW)system with dual-motor steering actuator's dual-motor anti-backlash control strategy based on applying variable bias current,by adding the backlash nonlinear model to the SBW system the effectiveness of dual-motor anti-backlash control strategy was verified;Finally,a comprehensive analysis of the dual-motor synchronous control strategy interacted with dual-motor anti-backlash control strategy was completed.(4)The d SPACE_DS1103 real-time simulation tool was used to build a steer-by-wire(SBW)system with dual-motor steering actuator hardware in the loop test bench,the dual-motor synchronous control and the dual-motor anti-backlash control strategy were verified with hardware in the loop test bench,the test results show that the proposed “angle following torque feedback” and dual-motor synchronous control strategy based on differential negative feedback and dual-motor anti-backlash control strategy based on applying variable bias current are effective,the implementation of the steer-by-wire(SBW)system with dual-motor steering actuator's good steering response capability can be ensured,and the dual-motor steering actuator system's synchronous and gear backlash impact problem can be solved too.