H2 Optimal Control Of Vehicle Semi-Active Suspension Based On MR Damper

The ride comfort and handling of vehicle are mainly judged by sprung mass acceleration,suspension rattle space and tire deflection.Ride comfort and handling are valued differently under varying working conditions of vehicle,so the dynamics of suspension system is supposed to change under different circumstances.Besides,to better isolate or attenuate the vibration of car body from road disturbance and keep road holding,the damping force of the suspension system is expected to vary with the state variable of the suspension system in real-time.The semi-active suspension system based on magneto-rheological damper can vary its damping force based on working conditions,suspension state variables and the weight of the three performance indexes to acquire the optimal ride comfort and handling.The thesis is organized in an order as following:First,the structure and operating principle of magneto-rheological damper is analyzed,and a mechanism-based magic formula model of hysteretic characteristic of magneto-rheological damper has been developed which is suitable for applying in control system.Second,a 2-DOF suspension dynamic model and a road disturbance model are established to draw the H2 optimal control algorithm under low-pass velocity white noise.Additionally,a state observer is designed to acquire the state variables used in the H2 optimal control algorithm.Then a Matlab/Simulink model of the semi-active suspension control system is built to verify the effectiveness of the algorithm and the MAP under different weights of sprung mass acceleration,suspension rattle space and tire deflection is acquired.Third,a semi-active suspension controller has been developed based on STM32F4 series micro controller and a driver circuit based on DRV8312.Processing in loop has been conducted using Simulink and Embedded Coder to verify the controller.Finally,test bench has been constructed to validate the semi-active suspension control system.