Proportional integral sliding mode control for the half-car active suspension system with hydraulic actuator

Abstract

The purposes of this paper are to present a new mathematical model and control technique for modeling and control of an active suspension system with hydraulic dynamics for a half car model. In this paper the new mathematical model is presented which will give a much more complete mathematical representation of hydraulically actuated suspension system for the half car model. The models presented taking into account all the pressure difference parameters inherent in the hydraulic cylinder. However, from the derived mathematical expression for the systems, It is found that the system suffer from mismatched condition problem due to the nature of the road disturbance which is not in phase with the control input. Thus, a new control technique is proposed that will be able to overcome the mismatched condition problem inherent in the system. In order to achieve the desired ride comfort and road handling and to solve the mismatched condition, a proportional-integral sliding mode control (PISMC) technique is presented to deal with the system and uncertainties. Extensive simulations are performed for different road profiles and the results showed that the proposed controller performed well in improving the ride comfort and road handling for the half car model using the hydraulically actuated suspension system. The results also showed that the system is completely insensitive to the external disturbance due to the road surface irregularities. Thus, it is also proved that the proposed controller is capable to overcome the mismatched condition problem that present in the active suspension system.