No abstract

The asymmetrical damping of a vibration-isolation system induces a change in the mean position of the isolated body. Inspired by this phenomenon, a novel idea to vertically shift an isolated body based on nonlinear system vibration with asymmetrical damping is proposed. The proposed idea can be applied in fields that require the isolated body’s height to be adjusted. A methodology based on the homotopy analysis method (HAM), which is used to obtain the approximate analytical solution of a piecewise-smooth vibration-isolation system, was developed to verify the feasibility of the proposed idea. The accuracy of the solution obtained by the HAM was verified by the Runge–Kutta method. Furthermore, based on the analytical solution, the effects of critical parameters on the vibration responses of the system were analyzed. Finally, the proposed idea was applied to vehicle height adjustments. Simulation results showed that vehicle height adjustments could be realized only using a semi-active suspension. This provides a novel methodology for vehicle height control.

The use of active suspension for vehicle height adjustment has problems of high cost, high energy consumption, slow response, and complex structure. This paper proposes a new method for adjusting the vehicle body using the damping asymmetric characteristic of semi-active suspensions, which is based on the idea that the dampers with damping asymmetric characteristics will cause a change in the mean position of the vehicle body vibration. To verify the feasibility of this method, a single-wheel vehicle model containing asymmetric damping is established. The system’s responses under the sinusoidal and random roads excitation are obtained by the fourth-order Runge-Kutta method, the influences of key parameters on the vehicle body’s shifting height are analyzed, and the mechanism of vehicle body’s shift is explained from the perspective of energy conservation. Then a vehicle body height controller based on third-order linear active disturbance rejection control (LADRC) is designed. Simulation results show that the proposed method for controlling the vehicle height with asymmetric damping can quickly adjust the vehicle to the expected height whether under the sinusoidal road or random road. In addition, no additional hardware and energy consumption are required, providing a new idea for vehicle height control.