Fractional order fuzzy backstepping adaptive controller for hydraulic suspension

Abstract

Nonlinear electro-hydraulic active suspension systems often suffer from strong coupling, time-varying uncertainties, and external disturbances, which degrade ride comfort and vehicle stability. This paper presents a novel command fractional fuzzy adaptive backstepping controller. First, a kinematic decoupling model is developed to separate suspension displacement from vehicle pitch and roll dynamics. Then, an adaptive control law is designed by integrating incommensurate fractional-order dynamics, command filtering to prevent complexity explosion, and a fuzzy-based switching gain mechanism driven by real-time suspension displacement variance. Simulation and experimental results demonstrate that the proposed controller effectively suppresses suspension displacement fluctuations, mitigates vibration transmission, and enhances robustness against external disturbances, outperforming conventional command-filtered adaptive control and backstepping adaptive sliding mode control approaches.