PERFORMANCE ENHANCEMENT BY CONTROL LAW ADAPTATION IN SLOW-ACTIVE ROADVEHICLE SUSPENSIONS

The paper is concerned with the possible performance improvements whic h can be obtained in an automotive active suspension system through th e use of adaptive rather than fixed control The study is wholly theore tical and treats a quarter-car, slow-active, electro-hydraulic-pneumat ic suspension with elastic limit stops. through simulation of running at a constant speed on randomly profiled roads. The adaptation is inte nded to adjust the system operation according to the prevailing road r oughness level. road spectral properties being assumed average at all times. The road roughness estimation process is illustrated. The estim ate is used to drive a gain scheduling adaptive scheme. Comparisons ar e made between adaptive slow-active systems, non-adaptive slow-active systems and a typical passive system. mainly by means of root mean squ are values of response variables. It is concluded that the assumptions made in such a study can exert a large influence on the nature of res ults obtained, giving rise to potentially conflicting interpretations. The present results indicate that adaptation of the type proposed has very limited value.