Modeling and μ Synthesis Control of Vehicle Active Suspension with Motor Actuator

YONGCHAO ZHANG, GUOGUANG ZHANG, FAN YU* State Key Laboratory Mechanical System & Vibration, School of Mechanical Engineering Shanghai Jiao Tong University 800 Dongchuan RD. Minhang District, Shanghai CHINA [email protected] Abstract: This paper presents the modeling and μ synthesis for a vehicle active suspension system with a motor actuator, and analyses the performances of the active suspension with μ synthesis controller. Firstly, considering parameter uncertainties and unmodeled dynamics of suspension and motor actuator, an uncertain model has been built by linear fraction transformation. Secondly, a μ synthesis controller is designed for this uncertain system. Finally, frequency and time responses of passive and active suspensions have been obtained by simulation. For comparison purpose, an H∞ synthesis controller is proposed as well. The results show that the designed μ synthesis controller can improve ride comfort significantly compared with passive suspension, and is slightly worse than the H∞ synthesis controller in the sensitive frequency range for human. Both robust stability and robust performance of the perturbed system with the μ synthesis controller have been verified by μ analysis method, indicating significantly superiority to the H∞ synthesis controller. Additionally, the sensitiveness of uncertainties is demonstrated by illustrations of perturbed systems with parameter variations.