ANALYSIS, MODELING AND CONTROL OF AN ADVANCED AUTOMOTIVE SELF-LEVELING SUSPENSION SYSTEM

The paper is concerned with the analysis, modelling and control of a p rototype self-levelling active suspension system for road vehicles. Mo tivation for the work is given by considering some of the fundamental performance limitations within which all traditional passive designs a re constrained to operate. Self-levelling systems are presented as a v iable engineering compromise from ideal 'fully active' designs which a re currently regarded as impractical owing to their associated cost an d fuel-consumption penalties. Early analyses are concerned with quanti fying the disturbance sources affecting automotive suspension systems: irregularities in road surface elevation and dynamic (inertial) force s resulting from driving manoeuvres such as steering and braking. Anal ysis of the suspension system itself includes linear and nonlinear dyn amic modelling of a single wheel station or 'quarter car', for which a suitable controller is designed. The analytical work is supported for both the active and passive suspensions by experimental results taken from a full-scale hydraulically powered quarter-car suspension test r ig.