A coaxial couple wheeled robot with T-S fuzzy equilibrium control

Purpose - The purpose of this paper is to introduce a high load capacity coaxial couple wheeled robot (CCWR) and investigate a simple structure but effective fuzzy equilibrium controller based on (Takagi-Sugeno) T-S for balance control in wide-angle range. Design/methodology/approach - By selecting the robot inclination angle and angular rate as input variables and the DC motors' rotation speed as output variables, a T-S fuzzy controller (FC) is established. Findings - Simplified robot dynamic equilibrium equations are feasible; the robot balance in wide-angle range could be controlled by the T-S FC. Despite the existence of small vibrations near the equilibrium position, the system can return to equilibrium within 3 s, showing strong robustness. Practical implications - The robot can achieve self-balance and pivot around, moreover, it provides a new way for balance control of CCWR in wideangle range. And at the same time, the robot can achieve its work in semi-autonomous and tele-operated mode. Originality/value - The paper shows that designing the controller based on static analysis is feasible; simple structure T-S fuzzy control way is introduced to balance control for CCWR in a wide angle scale; the development target is to provide a kind of robot platform for testing control algorithms or a personal transporter, and the project is supported by the High Technology Research and Development Program of China.