Develop of active suspension and experimental study of control strategy based on output feedback and frequency shaping

In this paper, a 2-DOF experimental equipment of active suspension is developed. This system is hydro-pneumatic type and is controlled through oil flow. A control strategy based on output feedback and frequency shaping is proposed and realized on this model. Output feedback can reduce the number of system states that should be measured and thus simplify the complexity and improve the reliability of the system. Because of the different human sensitivity to different frequency ranges of vibration, it is necessary to pay effort on the suppression of vibration according to human sensitivity. Frequency shaping technology is thus applied on performance index to improve the ride quality. Several types of measurement versions are investigated and optimized. Simulation results indicate that using sprung mass velocity and suspension deflection, the system performance can approach the full-state feedback system performance. Through test research, it is shown that this strategy is feasible and the ride quality can be greatly improved without deteriorating other aspects of performance index. Furthermore, the control strategy of this model can easily be extended to half- or full-vehicle model and more aspects of performance can be frequency shaped.