Institute of Complexity Science Qingdao University Qingdao Shandong 266071 China;
College of Information Science and Technology Qingdao University of Science and Technology Qingdao Shandong 266071 China;
Department of Basic Science Liaoning Institute of Technology Jinzhou Liaoning 121001 China;
Nonlinear systems; Fuzzy control; Robust adaptive control; Backstepping technique;