Design and Implementation of A Ride Height Control System for A Quarter Car with Active Car Suspension

Abstract

The active air suspension system has drawn recently the attention from the vehicle manufacturer because it can improve the stability of the vehicles and ride comfort by adjusting the ride height. Due to the nonlinear characteristics of air, it is very hard to regulate the ride height to the target value accurately. This project proposes an inflatable air spring to adjust the ride height in order to achieve a good ride handling capacity. In this project, a nonlinear mathematical model for a quarter car model with active air suspension and an air charging and discharging model are constructed. These models are used to design a suitable control method and verify the feasibility of the control methods. Comparisons among different control methods, such as feedback control method, fuzzy control and reference model method, are made.

The simulation results show that the performance is good under a suitable control method. In other words, the adjustment of the ride height can be finished within an acceptable speed and an acceptable precision can be obtained. Eventually, fuzzy controller is selected to implement to the ride height control (RHC) system by comparing the simulation results.

Furthermore, a RHC system is designed and implemented on a quarter car test rig (QCTR). A series of experimental results are used to verify the functionality of the RHC system