A Novel Adaptive Sliding Mode Control Approach Based on a Model-Free Technique for Nonlinear Car Active Suspension Systems

This paper presents a novel adaptive sliding mode control approach based on a model-free technique for nonlinear active suspension systems in cars. The proposed method comprises four key components: First, an intelligent proportional-integral control based on model-free principles is employed to introduce desired dynamics. Second, an extended state observer is utilized to estimate the system’s nonlinearities and unknown dynamics. Third, an integral sliding surface is integrated to eliminate the reaching phase, along with a noise-sensitive switching mechanism. Last, adaptive gain dynamics are incorporated to improve accuracy. This controller offers several advantages, including its simple structure and ease of adjustment. The study also includes analyses of theoretical system stability, convergence speed, and control accuracy. Finally, the proposed approach is validated using MATLAB simulations and compared with a recent paper on a two-degree-of-freedom nonlinear quarter-car active suspension system.