Model-free adaptive fuzzy logic control for a half-car active suspension system

Abstract

This paper presents a novel model-free adaptive fuzzy logic controller (MFAFLC) for vibration control of active suspension systems. The physical constraint of the half-car model is considered so that the parameter's variation and external disturbance which are simultaneously taken into account may provide a realistic framework. The control objective is to deal with the classical conflict between minimizing both the vertical and angular chassis accelerations which increase the ride comfort. On the other side, the dynamic wheel and suspension deflection remain within safety limits to ensure the ride safety. The proposed scheme contains three parts: the first one is, the model-free based intelligent PI controller which overcomes the existing controller's complexity, introduces requisite performances, and reduces the output high order derivative. The second one is the extended state observer (ESO) which is utilized to estimate the model unknown uncertain dynamics. The third one, the adaptive fuzzy logic based fractional order control is used to compensate the ESO estimation error online. The feature of MFAFLC is a quite simple structure and easy to be implemented. The entire closed-loop system stability is proved based on the Lyapunov theory and the Barbalat's Lemma. Finally, to demonstrate the performance of the proposed MFAFLC, the comparison with the classical PID, and intelligent PID is conducted under three different road disturbances.