Fuzzy Output Tracking Control of Vehicle Suspension with Input Constraint

Abstract

The paper presents a fuzzy output tracking control design method for electro hydraulic suspension system subject to input saturation constraint. Firstly, the nonlinear suspension system is represented by the Takagi-Sugeno (TS) fuzzy model, then, a T-S fuzzy controller is designed to reduce the H‡ tracking performance which is related to the output tracking error for all bounded reference inputs as small as possible under the input saturation constraint. In order to reduce the large number of inequalities involved in the controller design, a norm-bounded approach is used to handle the saturation nonlinearity. The proposed design for fuzzy controllers depends on feasible solutions of a set of linear matrix inequalities (LMIs) which can be efficiently solved by existing LMI Toolbox. To validate the effectiveness of the proposed approach, the designed T-S fuzzy controller is applied to force tracking control of an electro hydraulic suspension. It is confirmed by simulations that the designed controller can achieve better force tracking performance and improve the suspension performance accordingly.