Research And Development Of Electronic Control System For Vehicle Air Suspension

Vehicle air suspension system is a specific application object of air suspension control strategy.The design and development of its electronic control system is one of the directions that need to be developed urgently under the background of mature air suspension control strategy research.However,in the actual vehicle driving process,online optimization of the air suspension is difficult.Therefore,in order to balance robustness and online control cycle,this paper proposes a hierarchical dynamic control strategy based on interval.At the same time,combined with the existing electronic technical conditions of the laboratory,the layered air suspension electronic control system is designed and developed based on hardware and software.Finally,taking the existing modified vehicles in this laboratory as the research application object,the vehicle road experiment was carried out.The main research contents of this article are as follows:(1)To improve the comprehensive control performance of the vehicle,first complete the feasibility analysis of the control requirements and control strategies,and combine the previous research experience of this laboratory to establish the mathematical model and simulation model of the additional air chamber type air suspension system,A vehicle height control strategy is proposed,and a PID controller and an adaptive differential evolution(A-DE)controller are designed.Taking the modified vehicle in this laboratory as an example,the vehicle performance simulation experiments of PID control,A-DE control and uncontrolled air suspension system were carried out respectively.The simulation results show that: under low speed conditions,to improve driving comfort Compared with PID control,the A-DE control reduces the rms value of vertical acceleration at the center of mass of the vehicle body by 1.56%;under high-speed conditions,the reduction of tire dynamic load is the control goal,and A-DE control compares with PID control of four wheels.The average root mean square of tire dynamic load is reduced by about 11.01%.Therefore,combined with the actual driving habits and related laws and regulations,a layered dynamic control strategy based on intervals is proposed to provide a basis for the subsequent control software design.(2)Combining with the existing technical conditions of the laboratory,with the STM32F103ZET6 single-chip microcomputer as the core,a layered air suspension electronic control system hardware design and development was carried out,including:minimum system circuit,upper and lower signal processing circuit,CAN communication circuit,lower layer drive circuit and Other functional circuits.And complete the PCB-Layout design and production of the controller.(3)On the basis of completing hardware development,using MDK5 development tools,combined with Simulink / RTW automatic code generation technology,designed a layered electronic control system software,mainly including: upper and lower system main program,initialization program,CAN communication module,layer Control strategy program,vehicle height control program and stepper motor driver,etc.And after the program is compiled and downloaded to the controller designed in this paper,the basic function test of the layered electronic control system is completed.(4)Using the modified vehicle in this laboratory as the experimental application object,the static vehicle height control experiment and the vehicle road experiment were carried out.The experimental results show that although the subjective feelings of the modified vehicle have not reached a very ideal state,they are still compared.The uncomfortable improvement is somewhat uncomfortable.Considering the existence of uncontrollable factors such as the vehicle itself and measurement errors,the air suspension electronic control system designed in this paper has good stability,reliability and control performance.