Optimal Active Vehicle Suspensions with Full State Feedback Control

The transmission of road-generated vibrations to a vehicle body is treated as a source-path-receiver problem. The suspension system acts as the bidirectional path for transmitting forces and movements from the body to the wheels. Certain limitations are imposed by passive components such as springs and dampers. However, improved suspension performance is achieved if an active element is employed to control forces and relative velocities. The complexity, power requirements and cost of fully active suspensions have restricted their use. In optimally controlled active suspensions with either full or incomplete state feedback there exists a trade off between system performance and the overall stiffness. Most of the reported investigations on the optimal active suspensions indicate that the performance measure depends on the input signal, in this case being the road surface irregularities. An adaptive control technique for active vehicle suspension is presented in this paper. This method could automatically self-tune the active vehicle suspension such that disturbances of dynamic parameters have no effect on the dynamic performance of the system. It is shown that the state variables may be such defined that the performance measure would be made independent of the input signal.