Design and analysis of a pseudo-active suspension

Abstract

Compared with active suspensions, semi-active suspensions combine the advantages of low energy consumption and simple structure, but have relatively poor system performance. To improve the performance of semi-active suspensions, the general skyhook-groundhook hybrid strategy has been proposed, breaking the transfer function consolidation of semi-active suspensions under the traditional skyhook-groundhook hybrid control. However, the inherent limitations of the skyhook-groundhook hybrid control and semi-active suspensions result in poor optimization: suspensions under the general skyhook-groundhook hybrid control cannot truly achieve mechanical properties of connection with the sky and the ground. The lack of active control force in semi-active suspensions results in excessive limitations during the optimization process. This paper aims to combine the advantages of the active and semi-active suspension to design a new suspension with both high performance and low energy consumption. A body-on-frame structure is applied to redesign the mechanical network of the vehicle suspension, truly achieving the equivalent mechanical properties of the general skyhook-groundhook hybrid strategy. A mechanical compensation mechanism is used to design negative stiffness and damping mechanisms in the vehicle suspension, so that the partial impedance function of the suspension network can break through the constraint of “positive-real”. Then a new actuator with active mechanical properties − a pseudo-active actuator is designed based on the principle of mechanical compensation mechanism. This actuator consists of two semi-active actuators and a mechanical compensation mechanism. It can achieve four-quadrant controllable mechanical properties conditionally with semi-active actuators. Finally, a pseudo-active suspension was designed by combining the new suspension structure and a pseudo-active actuator. Through simulation and experimental verification, the performance of pseudo-active suspensions is significantly improved compared to that of semi-active suspensions and is similar to that of active suspensions.