Adaptive Control Of The Vehicle’s Active Suspension With Actuator Saturation And Disturbance

The suspension consists of shock absorber, spring and guide mechanism usually and itlies between the vehicle’s bodywork and wheel. Automotive suspensions have effect on theride comfortably and the stability directly. The passive suspensions have a constant spring.When the vehicle is driven on different road, the system couldn’t reach the optimal state. Thus,the concept of the active suspension is born at the right time. The active suspension can adjustto the suspension’s control in real time to reduce the vibration of the car, according tothe road conditions and environment. At the same time, the car has been driven for a long time,the actuator also operated continuously, the actuator could easily reach saturation state orpartial failure.We take into consideration the control strategies for the active suspension with actuatorsaturation and partial failure. First of all, based on the vehicle dynamics theory, we constructtwo degree-of-freedom and a quarter of the vehicle mathematical model. Then, we make useof state feedback method and output feedback method to design the adaptiveH∞controller.The controller can forecast the fail rate of the actuator in real time and compensate theactuator under the condition of the state feedback and output feedback respectively. The twofeedback methods make sure the system is stability or asymptotic stability.Using MATLAB/Simulink to construct the active suspension simulation model, and weuse adaptiveH∞algorithm to design the controller. At the same time, we compare theconventional fixed-gain controller’s suspension performance index with the adaptiveH∞controller’s suspension performance index, concluding that the adaptiveH∞controllerhas better effect than the fixed-gain controller. Then, we observe the same state variableoscilloscope on different control strategies.The active suspension with adaptiveH∞controller,the amplitude of the bodywork’s speed and the amplitude of the suspension’s speed are allless than under the fixed-gain controller, also earlier back to equilibrium state. That’s means that the active suspension with adaptiveH∞controller has better robustness, the adaptiveH∞control strategy is more applicable to the active suspension.