Road-adaptive nonlinear design of active suspensions

Recently (1995) we proposed a novel nonlinear control design for active suspensions, which features a filter whose bandwidth is a nonlinear function of suspension travel; this filter results in an improved tradeoff between ride comfort and rattlespace usage. In this paper we augment this controller with a new road-adaptive algorithm which continuously monitors suspension travel and adjusts online the shape of the filter nonlinearity in response to different road profiles. This adaptive design realizes the true potential of active suspensions, which is their ability to yield better performance over a much wider range of road surfaces than passive suspensions.