Residual swing/vibration reduction using a hybrid input shaping method

This paper addresses a hybrid input shaping method to reduce the residual swing of a simply suspended object transported by a robot manipulator or the residual vibration of equivalent dynamic systems. The method is based on the successive use of two input shaping methods. A cycloid is chosen as the trajectory to be preshaped. First of all, a ramp function is superimposed onto the cycloid and then the resulting trajectory is convolved with a sequence of two impulses. The resulting trajectory is preshaped twice. A hydraulically actuated robot manipulator carrying a simply suspended object is employed as the experimental system. Simulation and experimental results for each method constituting the hybrid method are presented and compared to what we call hybrid input shaping method. The results indicate that a swing-free stop is obtainable at the end of a move with a high degree of robustness to uncertainties in the natural frequency of the swinging or vibrating system by employing the hybrid method. The method is simple and easy to implement, and most importantly robust to uncertainties (±15% of ωn) in the natural frequency of the system.