Abstract

The paper outlines a systematic method for controlling suspension deflection offset and drift, that can arise when an actively sprung vehicle encounters a constant gradient or a long wavelength road surface undulation. A brief review of the problem is given and it is shown that the inherent filtering effects of a standard Kalman observer does not sufficiently address the issue. An expanded Kalman filter is introduced to estimate the underlying vertical road velocity, and this is applied within a linear state feedback controller. Its effect on suspension performance is shown to be advantageous when compared with simpler state feedback and integral control techniques.