Development Of Active Suspension Controller For Mobile Rescue Vehicle

Suspension system is an important device for maintaining body stability and ride comfort of mobile rescue vehicle.At present,the traditional rescue vehicle suspension system in China mostly uses passive suspension.When the rescue road conditions are rugged,the performance of the rescue vehicle with passive suspension is often difficult to meet the actual needs.Active suspension system can greatly improve vehicle stability and ride comfort by precisely controlling the output force of servo actuator to offset the impact of rough road surface.Therefore,it is of great significance to study the mobile rescue vehicle with active suspension system to improve the rescue efficiency.The servo actuator PID control algorithm of active suspension system of mobile rescue vehicle is designed.According to the limited chassis space of the mobile rescue vehicle,the fourway valve controlled asymmetric hydraulic cylinder was selected as the servo actuator of the active suspension system.The mathematical model of the four-way valve controlled asymmetric hydraulic cylinder is established,and PID control algorithm is used to control the four-way valve controlled asymmetric hydraulic cylinder,so that the desired force can be quickly output according to the needs.Matlab/Simulink is used to verify the simulation results,and the simulation results meet the design requirements.A fuzzy PID algorithm for active suspension system of mobile rescue vehicle was designed.Taking the displacement and acceleration of the body in the vertical direction as the important indexes to evaluate the ride stability of the vehicle,the road input and the active suspension model of a quarter of the vehicle were established.Based on the characteristics of the four-way valve controlled asymmetrical hydraulic cylinder and the quarter-vehicle active suspension model,a two-dimensional fuzzy PID controller was designed to control the active suspension system of the movable rescue vehicle.B-class road surface and block road surface were taken as simulation test conditions,and the curves of vertical displacement,vertical acceleration,suspension displacement and tire deformation were obtained under the condition of changing body mass.Compared with the effect of passive suspension and traditional PID controller,the effect of fuzzy PID controller is obviously superior for the two technical indexes of body vertical displacement and acceleration,and the suspension displacement and tire deformation are also kept within the range,meeting the requirements of vehicle driving stability.The hardware circuit and software of the controller of the active suspension system of the mobile rescue vehicle are designed.The core of the controller adopts low power consumption and high precision STM32F373CCT6 microcontroller.Hardware circuit includes embedded microprocessor basic peripheral circuit,acceleration and pressure sensor signal acquisition circuit,power supply circuit,sine wave self-excited oscillation and voltage to current circuit,CAN communication circuit.The software design includes the main program,fuzzy PID control algorithm program,SDADC data collection program,CAN communication program.The hardware circuit was simulated and verified by Multisim,and the test platform of the active suspension system controller of the mobile rescue vehicle was built.The simulation and actual test results show that the designed active suspension system controller meets the design requirements.