H∞ control of uncertain seat suspension systems subject to input delay and actuator saturation

This paper presents a control synthesis method for a class of semi-active seat suspension systems with input time delay, parameter uncertainties and actuator saturation. A vertical vibration model of human body is employed and put together with the plant of the seat suspension system in order to gain a better insight of the control performances. The H_∞ performance is used to measure ride comfort so that more general road disturbances can be considered. By defining a Lyapunov functional and exploring the property of the saturation nonlinearity, the existence conditions of the desired state-feedback controller are derived. An illustrative example is presented to demonstrate the usefulness and effectiveness of the developed theoretical results.