Robustness analysis of magnetorheological elastomer-based vibration isolation system with optimal fuzzy controller

Due to adjustable stuffiness with applied magnetic fields, magnetorheological elastomer (MRE)-based vibration isolation method has attracted more attention in vibration engineering fields, such as precision-fabrication or precision-measurement platform for high-tech facilities, civil structure. However, there exists parameter uncertainty in dynamic model of control system, such as variation load mass in different working conditions, increasing or decreasing stiffness due to the rubber aging induced by the temperature and humidity of the environment. So it is necessary to investigate and evaluate quantitatively the robustness of MRE-based vibration isolation control system. This paper addresses that. Firstly, the dynamic model of MRE vibration isolation system with consideration of uncertain stiffness of the isolator and load mass is established. Then, a fuzzy controller (FC) is designed under the certain amplitude and frequency excitation, the parameters of FC are optimized by genetic algorithm. On this basis, RI (robustness index) is proposed to divide the robustness of the system under variation of parameters (stiffness of MRE isolator and load mass) as ‘good’, ‘fair’ and ‘poor’ level. Lastly, simulation and experiments are carried out to evaluate quantitatively the robustness performance of MRE vibration control system with designed optimal FC, respectively. The results show that the designed optimal FC has greater RI than experienced-based FC for different variation range stiffness of MRE isolator and load mass, and demonstrates outstanding robustness.