Robust fault-tolerant H∞ control of active suspension systems with finite-frequency constraint

• A full-car suspension model is used in the controller design.
• A robust dynamic output-feedback controller with fault-tolerant ability is designed.
• Finite-frequency constraint is considered in the controller design.
• Ride comfort is improved and the suspension hard constraints are also guaranteed.

In this paper, the robust fault-tolerant (FT) H∞H∞ control problem of active suspension systems with finite-frequency constraint is investigated. A full-car model is employed in the controller design such that the heave, pitch and roll motions can be simultaneously controlled. Both the actuator faults and external disturbances are considered in the controller synthesis. As the human body is more sensitive to the vertical vibration in 4–8 Hz, robust H∞H∞ control with this finite-frequency constraint is designed. Other performances such as suspension deflection and actuator saturation are also considered. As some of the states such as the sprung mass pitch and roll angles are hard to measure, a robust H∞H∞ dynamic output-feedback controller with fault tolerant ability is proposed. Simulation results show the performance of the proposed controller.