Abstract: The problem of point to point positioning and simultaneously vibration suppression for the joint-driven flexible-arm system is researched. Based on the closed-loop dynamics, the servo-feedback constraints theory and Rayleigh-Ritz method are combined to model the flexible-arm vibration partial differential equation including joint controller effects, and then the feasibility of the proposed issue is proved. The system output is redefined by the differential geometry input/output linearization method to decompose the original system into two parts, namely input/output subsystem and internal subsystem, and the zero-dynamics equation is derived accordingly. A global terminal sliding mode control strategy is proposed to make the input/output subsystem states attenuate to zero in limited time, while the inherent chattering existing in conventional sliding mode control is eliminated significantly. Moreover, the global system can be Lyapunov asymptotical stable by selecting zero-dynamics subsystem controller parameters by using the pole assignment method. The numerical simulations and experimental results confirm the validity of proposed control strategy, which is realized by using only the joint motor.

Key words: Flexible-arm, Global terminal sliding mode control, Input/output linearization, Nonminimum phase, Servo-feedback constraints