Control Research On Vehicle Semi-active Suspension With Electro-hydraulic Actuator

The traditional passive suspension's stiffness and damping can not be adjusted,which can not solve the contradiction between the ride comfort and handling stability,so the vibration reduction effect is so poor,and it will dissipate the vibration energy into the atmosphere by friction action,therefore,it violates the purpose of energy saving and emission reduction.The regenerative semi-active suspension with electro-hydraulic actuator in this study can not only adjust the parameters to improve the vehicle ride comfort,but also can recover the vibration energy of the vehicle.Based on the analysis of the structure and principle of the EHA regenerative semi-active suspension,the semi-active suspension is modeled,and the sensitivity of some parameters of the suspension is analyzed;The comprehensive performance evaluation system of the feed energy suspension is established by using the combination weighting method and the TOPSIS method,based on the comprehensive performance evaluation system,some design parameters of the suspension are optimized by using the DOE experimental design method;The mechanism of how the time delay of the suspension was generated is analyzed,the formula for calculating the critical delay of the delay system is derived,the fuzzy controller of the semi-active suspension is designed,the influence of time delay on the semi-active suspension with fuzzy control is studied,the improved Smith predictor compensator is used to compensate the time delay of the semi-active suspension with fuzzy control,the compensation effect and the anti-interference ability of the time-delay compensator are simulated and analyzed.The physical prototype of the suspension was developed and the suspension vibration test bench was built.On this basis,the damping characteristics,energy release characteristics and the effect of time delay compensation of the suspension were tested by bench test.The vibration performance of the suspension is studied by using the multifunctional electric vehicle test platform.The results of simulation and experimental show that:the optimization of suspension parameters which based on the comprehensive performance evaluation system can effectively improve the performance of the EHA regenerative semi-active suspension;The improved Smith predictor compensator can effectively reduce the influence of time delay on the suspension.At the same time,the time-delay compensator has good anti-interference ability;The test results of damping characteristics and feed energy characteristics of EHA regenerative semi-active suspension show that the damping characteristics of suspension can meet the requirements of semi-active suspension.When the input frequency is 1-2Hz,and the amplitude is 10mm,the average energy recovery power of the suspension is 10W-35W;The real vehicle road experimental results show that compared with the passive suspension the semi-active suspension can improve the ride comfort of the vehicle effectively.