Active Hydro-Pneumatic Suspension Active Disturbance Rejection Sliding Mode Control for Improved Vehicle Stability

<div class="section abstract"><div class="htmlview paragraph">Hydro-pneumatic suspension is widely used because of its desirable nonlinear stiffness and damping characteristics. However, the presence of parameter uncertainties and high nonlinearities in the system, lead to unsatisfactory control performance of the traditional controller in practical applications. In response to this challenge, this paper proposes a novel stability control method for active hydro-pneumatic suspension (AHPS). Firstly, a nonlinear mathematical model of the hydro-pneumatic suspension, considering the seal friction, is established based on the hydraulic principle and the knowledge of Fluid dynamics. On the basis of the established hydro-pneumatic suspension nonlinear model, a vehicle dynamics model is established. Secondly, an active disturbance rejection sliding mode controller (ADRSMC) is designed for the vertical, roll, and pitch motions of the sprung mass. The lumped disturbance caused by the model nonlinearities and uncertainties is estimated by the extended state observer (ESO), which is then integrated into the sliding mode control law. This allows the control law to actively adapt to the working state of the suspension system, which can effectively address the impact of uncertainties and nonlinearities on the system. Finally, the simulations are carried out on bump and random roads, two typical working conditions. The results show that the proposed ADRSMC can reduce the amplitude of vehicle acceleration by more than 50% compared to traditional passive hydro-pneumatic suspension, and the optimization effect is better than active disturbance rejection control ADRC). It significantly improves the stability of the vehicle. This study provides a valuable reference for the design of active hydro-pneumatic suspension control strategies.</div></div>