Vehicle stability control for active hydro-pneumatic suspension with active disturbance rejection sliding mode control

Hydro-pneumatic suspension is widely used for its desirable nonlinear stiffness and damping characteristics. However, with the presence of parameter uncertainties and inherent nonlinearities, traditional controllers often yield unsatisfactory control effects in practical applications. Therefore, a novel stability control method for active hydro-pneumatic suspension is proposed in this paper. First, a nonlinear mathematical model of the hydro-pneumatic suspension considering the seal friction and a full vehicle dynamics model is established. Second, the vertical, roll, and pitch motions of the vehicle body are collaboratively controlled by establishing three active disturbance rejection sliding mode controllers (ADRSMC) in parallel with each other. The lumped disturbances caused by the model nonlinearities and uncertainties are estimated by the extended state observer (ESO), integrating these into the sliding mode control (SMC) law to enable adaptive system response. Finally, the effectiveness of the proposed control method is verified under the bump and random road surfaces. The results demonstrate that the proposed ADRSMC has better performance than the ADRC method and SMC, significantly improving the vehicle stability.