Research On Observer-based Magnetorheological Semi-active Suspension Control

Firstly, based on the vehicle dynamics theories, the dynamics model of the quarter-car and half-car semi-active suspension system has been designed in this dissertation. Analysised the filtering Gaussian white noise random input model, using MATLAB/Simulink simulated a typical B-class random road surface time-domain signal. A Kalman filter has been Designed to estimate the relative speed and absolute speed of the suspension, in order to improve the control effectiveness of the observer, on the basis of the Kalman filter, a slide mode switch is used to design slide mode observer. According to a skyhook control algorithm, a skyhook controller based observer has been established for a quarter-car semi-active suspension system. MATLAB/Simulink simulation shows that the Kalman filter can estimate the absolute speed and relative velocity of the suspension effectively, and the sliding mode observer is better and stable than the Kalman filter. Furthermore, the results show that observer-based skyhook control strategy is better than the passive suspension in ride and safety.With magneto-rheological (MR) damper experimental platform, performance testing has been conducted for a commercial MR damper. On the basis of the test data, a polynomial model of the MR damper has been founded, as well as its anti-model, which made a foundation for open-loop control of the MR damper.Semi-active suspension real-time monitoring and controlling system was established in the laboratory. The NI/CompactRIO was the core of the control unit, using a quarter-car vehicle semi-active suspension control test bench for observer-based skyhook control of semi-active suspension was tested. Tests show that the observer can better estimate the state of suspension, observer-based control strategy skyhook suspension system for better control and improve the vehicle's dynamic performance.Finally, vehicle road test was conducted. The two front shock absorbers of a real car passive suspension were replaced by MR dampers. After building NI/CompactRIO real-time monitoring and control test system, road tests was carried out at different speeds. Experimental studies show that the skyhook controller based on MR damper can effectively improve the ride comfort, and can be used for real vehicle controller development.