DESIGN OF AN ACTIVE SUSPENSION FOR A PASSENGER VEHICLE MODEL USING INPUT PROCESSES WITH TIME DELAYS

SUMMARY

In vehicles with traditional passive suspension, the spring and damping elements between car body and axles have a fixed characteristic. This means that when the suspension is adjusted, a compromise between comfort and safety has to be arrived at. With active suspension, on the other hand, both these criteria can be enhanced at the same time. Moreover, further improvements in driving behaviour can be made which are not possible with passive suspension. In this case, the time delay between front and rear axle excitation is represented by a fadé approximation, which means that linear controller design methods in the state space (Riccati controller, Kalman filter) can be used to implement active vehicle suspension. A spatial model of a medium-range passenger vehicle is augmented by a disturbance model (stochastic dual track excitation of the road surface with excitation delay time, if need be with irregularity sensors), a perception filter (weighting of human sensitivity to vibration) and a filter for the dynamics of the actuators.