Nonlinear dynamics and control of connected hydro-pneumatic suspension with fractional order.

This paper develops a four-degree-of-freedom dynamics model with fractional order based on an anti-roll connected hydro-pneumatic suspension of a four-axle vehicle. A comprehensive evaluation function determines the optimal order. The effects of the excitation parameters and the suspension's internal parameters on the system's nonlinear dynamics are investigated under sinusoidal superimposed white noise excitation. According to the simulation analysis, the system gradually stabilizes as the excitation amplitude and frequency increase. The flow coefficient variation does not affect the system. The initial pressure shows the system's chaotic and transient periodic motion in the study interval. By establishing a double power convergence sliding film variable structure controller to control the suspension, the chaos is effectively suppressed by comparing the before and after control. • In order to express the stiffness and damping force of hydro-pneumatic spring more accurately, a four-degree-of-freedom dynamic model with fractional order is established in this paper, and the best order is determined by comprehensive evaluation function. • The effects of excitation amplitude and frequency, flow coefficient and initial pressure on the motion state of the system are analyzed by means of nonlinear dynamics. • A dual-power convergent sliding mode variable structure controller is established to control the suspension and effectively suppress the chaotic vibration. [ABSTRACT FROM AUTHOR]