New Vehicle Active Suspension System And Its Robust Control

Suspension is the main part of the vehicle, it lies between body and wheels. Usually, the suspension is composed of the spring and damper elements. It has two main performance requirements, ride comfort and handling stability. But the two main performance requirement is conflicted.The passive suspension using at large has fastness spring stiffness coefficient and damper coefficient, so it can only meet the compromise of the conflict among the ride comfort and handling stability at the structure design. Therefore, the active suspension came into being from five or six decades. It can improve the conflict relation among the ride comfort and handling stability. But the active suspension system has some limitation such as complex structure, high technology , valuable cost and big power, where limit the high performance system to apply abroad on the vehicle system.This paper presents a novel active suspension system to resolve the conflict of the performance and the cost base on the theory study. And hope it can advance the abroad appliance of the active suspension system. The novel system which is newly designed uses gas spring/damper unit, then has the spring and damper in the same unit. The compressibility of the fluid and the gas provide the hydraulic spring and the gas spring, and the connecting damper hole provides passive damper force, and the fluid mass in the chambers can be changed using a serve valve controller to get suitable control force. Thus it has the active damper simultaneity. Comparing with the conventional coil-spring suspension, the new active suspension system ensures ride height remains constant regardless of load conditions.Firstly, tow degree-of-freedom DOF the quarter-vehicle's dynamic model using the state equation has been set up. Secondly, do some work to design robust active suspension. First of all, we give the problem of active suspension 2DOF quarter vehicle system control and description of performance requirements. In order to harmonize conflict performance requirement and emphasize sensitivity of vertical...