Traditionally, a quarter-car model and a sky-hook controller are employed to derive analytical expressions that describe conditions for self-powered operation. The main contribution of this work consists in using a seven degree of freedom vehicle model to determine numerically the condition for self-powered operation of an active suspension system with electromagnetic actuators. The performance of proportional–integral–derivative, linear quadratic regulator, and fuzzy Logic suspension controllers that employ feedback information for heave, pitch, and roll motion is evaluated under self-powered operation. An objective function consisting of a weighted sum of performance measures, including root mean square values for accelerations, road holding, actuator travel, and power regeneration capability, is used to determine equivalent actuator damping values and controller gains that enhance self-powered operation. The resulting optimal designs for each control strategies are compared by means of frequency responses to evaluate their performance and power regeneration capability, as well as to determine the effect of self-powered operation on these characteristics. This investigation shows that the performance of a self-powered active suspension systems, based on heave, pitch, and roll motion information, can be optimized to approach that of an active suspension system with external power supply; the degree of degradation depends on the particular suspension controller and the design objectives that are adopted. The performance improvement compared to a suspension system designed using a quarter car model and a sky-hook controller is also presented.
H∞ dynamic output feedback control for a networked control active suspension system under actuator faults
