A Design Synthesis Method for Robust Controllers of Active Vehicle Suspensions

Shenjin Zhu,Yuping He

doi:10.3390/designs6010014

Abstract

This paper presents a design synthesis method for robust controllers of active vehicle suspensions (AVSs). Various control techniques have been applied to the design of AVSs for enhancing ride comfort and handling performance of ground vehicles. However, most of these model-based controller designs show poor robustness when the vehicle models are not accurate and operating conditions vary. To address the poor robustness problem of AVSs, a new controller is designed using the H∞ loop-shaping control technique. The controller targets robustness issues on vehicle models with parametric uncertainties and unmodelled dynamics. To facilitate the robust controller design, a design synthesis method is proposed: the H∞ loop-shaping controller design is formulated as a multi-objective optimization problem, the weighting functions’ parameters of the controller are treated as design variables, the expensive computing loads are handled by a parallel computing technique, and the solution of the optimization problem is the desired robust AVS controller. Simulation results demonstrate the benefits of the proposed AVS design.

Highlights

With given elastic and damping features, passive vehicle suspensions show poor ride quality when traveling in severe operating conditions, e.g., low frequency bumps, pit holes, and high frequency road irregularities [1]
This paper proposes a design synthesis method for robust controllers of active vehicle suspensions (AVSs)
The robust controller and the vehicle model are integrated to form a virtual vehicle with robust active suspensions

Summary

Introduction

With given elastic and damping features, passive vehicle suspensions show poor ride quality when traveling in severe operating conditions, e.g., low frequency bumps, pit holes, and high frequency road irregularities [1]. It is demonstrated that these LQG/LQR-based controllers exhibit poor robustness to operating condition variations, parametric uncertainties, unmodelled dynamics, and external disturbances [9,10]. To address the poor robustness of these LQG/LQR-based controllers, robust control techniques, e.g., H∞ [11] and sliding-mode control [12,13,14,15], have been applied to the design of active vehicle safety systems. The H∞ control technique has been successfully used for addressing robustness problems on models with external disturbances and parametric uncertainties [19,20,21]. To tackle the aforementioned problems associated with the H∞-based AVS controller designs, this paper proposes a design synthesis method for the H∞ controller of AVSs. A robust H∞ loop-shaping controller (LSC) is designed for an AVS of a vehicle represented by a quarter-car model.

Vehicle Model

D21 D22 u

Proposed Design Synthesis Method

Results and Discussion

Conclusions