Constrained Active Suspension Control with Parameter Uncertainty for Non-stationary Running Based on LMI Optimization

Abstract

The research on a constrained robust H∞ control of half-car active suspension-based linear matrix inequality (LMI) optimization method was carried out for non-stationary vehicle running conditions in this study. The H∞ state feedback controller of active vehicle suspension system was proposed which contains the time-domain hard constraints and differential equation model of the half-car control system with parameter uncertainty for non-stationary running was established. The results of vehicle dynamics analysis indicate that the dynamic performance of this half-car active suspension controlled by the proposed control strategy is obviously superior to the performances of passive suspensions. The proposed control strategy shows good stability, even though vehicles are in non-stationary running and the actual system parameters (including unsprung mass, suspension rigidity, and tire rigidity) are uncertain. Moreover, besides improving the vehicle ride comfort, the proposed control method can also ameliorate the dynamic flexibility of vehicle suspension system, static-dynamic load ratio response characteristic of vehicle tyres, and requirement of constrained control forces.