Proportional–integral–derivative type H_∞ controller for quarter car active suspension system

This paper presents a linear matrix inequality based Proportional-Integral-Derivative (PID) type H_∞ controller design for a quarter car active suspension system. The model of the real system is derived with the help of identification techniques. The conventional H_∞ controller design method and PID tuning techniques are used to derive H_∞ controllers for this model. The performance of these controllers is compared in simulation and application phases. The response of a real time system can be quite different, due to some unmodeled parametric uncertainties and/or environmental noises which may arise during operation, and this undesired effect increases proportionally with the order of the controller. Therefore, it is inevitable to get more inconsistent solutions with high order controllers than low order ones. Disadvantages of full order controllers are discussed not only in the simulation phase but also in application phase. All results demonstrate the effectiveness of the proposed method.