Research On Magnetorehological Semi-active Vehicle Suspension System Design And Integrated Control

In recent years,with the improvement of vehicle performance requirements and the need for the development of a new generation intelligent connected vehicles,intelligent and integrated X-by-wire chassis and integrated control technology have become the key areas of the development of the automotive industry.Magnetorheological semi-active suspension and brake-by-wire system are important means to control vehicle vertical dynamics and longitudinal dynamics,which have important influence on vehicle performance.How to design the integrated control system aiming at the dynamic coupling relationship of the two systems to improve the ride comfort and handling stability of the vehicle is significant for the development of the wire-based control chassis and the integrated control technology.According to the research actuality,there are still three core problems to be solved in the design of integrated control system using magnetorheological semi-active suspension and brake-by-wire system:(1)How to establish the structure parameter optimization method of magnetorheological damper(MRD)and design the MRD to meet the performance requirement of vehicle;(2)How to design the magnetorheological semi-active suspension control system under the integrated control system architecture aiming at the response characteristics of the MRD and the suspension control requirements under different working conditions;(3)How to design an integrated control system aiming at the coupling relationship between magnetorheological semi-active suspension and brake-by-wire system and the output limitation of actuator,so as to improve vehicle handling stability and ride comfort.With regard to these questions,the main work of this study are as follows:(1)Structural parameter optimization of MRD for vehicle performance.In view of the disconnection between the parameter optimization of the MRD and the vehicle performance in the existing studies,the structural parameter optimization problem was described and the optimization process of structural parameters is established based on the analysis of the configuration of the dual-coil magnetorheological damper.Then a vehicle optimization simulation platform including multiple physical field models of magnetorheological shock absorber is built,and the structural parameters of the shock absorber are optimized by using improved genetic algorithm.During the optimization process,the magnetic field finite element model and the parameter dynamic boundary model created by BP neural network can significantly improve the efficiency of optimization simulation.A bench test was carried out for the optimized dampers and the test results show that the optimized dampers can meet the suspension control requirements and the output damping force has good linearity.(2)Design of dual close-loop drive control system for MRD.Firstly,a new type dual close-loop drive control system architecture for MRD is proposed aiming at the dynamic response characteristics of MRD.Secondly,the nonlinear mutual-inductance characteristics of MRD the process of dynamic response are modeled and a new type variable structure current driver is designed after the requirement of drive circuit defined.Thirdly,a current loop ADRC-switch controller is designed based on the control demand of variable structure current driver,and a damping loop Dahlin compensation controller is designed aiming at the inertial link of the system.Finally,the Simulink-PSpice co-simulation platform is established,and the simulation of the dual closed-loop drive control system under typical working conditions is carried out to verify the improvement of the control effect of the dual closed-loop drive control system on MRD's current and output damping force.(3)Research on the adaptive predictive control algorithm of semi-active suspension for non-emergence conditions.Firstly,in view of the different vibration characteristics and control requirements of vehicles in different working conditions,a multi-working condition adaptive predictive control algorithm based on road roughness identification and considering longitudinal and lateral inertial forces is proposed and the vehicle model prediction controller is created.Secondly,a support vector machine for road roughness classification based on suspension input power estimation is proposed and a multi-condition predictive control weight adaptive regulator considering longitudinal and lateral inertial forces,caused by steering and braking,is designed.Finally,a Matlab-Carsim co-simulation platform for semi-active suspension predic-tion control algorithm is built and control effect of adaptive predictive control algorithm under various non-emergence conditions is verified.(4)Research on the integrated control system of magnetorheological semi-active suspension and brake-by-wire system.An integrated control system of magnetorheological semi-active suspension and brake-by-wire system is designed by using the brake-by-wire system developed by the research group.Aiming at the coupling relationship between the two systems and the output limitation of the actuator,an integrated control mechanism is established based on sharing the prediction information of the actuator.Secondly,several subsystem controllers in the integrated control system are designed,which contains mixed groundhook controller for semi-active suspension,slip rate tracking sliding mode controller with prediction correction for brake-by-wire system,the vehicle stability fuzzy PID controller and Wheel brake pressure tracking time-sharing controller.Thirdly,an matlab-carsim co-simulation platform for integrated control system which includes the model of MRD and brake-by-wire system was built,and some parameters of the brake-by-wire system were identified.Finally,the simulation test of the integrated control algorithm is carried out using the co-simulation platform under emergency conditions,to verifies the effectiveness and rationality of the control algorithm.(5)Integrated control system hardware in loop test.An hardware in loop testrig for Integrated control system,which contains semi-active suspension testrig,brake-by-wire system testrig and central computing & control platform is built.Secondly,the magnetorheological semi-active suspension system was tested under non-emergency conditions using the HIL testrig to verify the driving ability of the dual close-loop drive control system for MRD and the control effect of the adaptive predictive control algorithm.Finally,the integrated control system of magnetorheological semi-active suspension and brake-by-wire system is tested on the HIL testrig under emergence conditions,to verifies the correctness and effectiveness of the integrated control algorithm and the actuator driving control algorithm.