Design of an Improved Robust $H_{\infty}$ Controller for Active Suspension with Input Delays

This paper proposes an improved robust H_∞ output-feedback controller design for vehicle active suspension system with input time-delay. By establishing a multi-objective control optimization problem, in which body acceleration is taken as the control objective, and suspension dynamic deflection, tire dynamic load and the actuator maximum control force are formulated as the constraints performance indexes in terms of linear matrix inequality. Afterwards, the robust H_∞ controller design with input delay is transformed into a delay-free system through Lyapunov stability theory and integral term transformation method. A numerical simulation investigation is presented to show that the proposed controller can achieve a good suspension performance under both random and bump road surfaces in the presence of input time-delay.