Robust and time-optimal control strategy for coarse/fine dual-stage manipulators

A robust and time optimal control strategy for dual-stage manipulator is presented. The time optimal trajectory for a mass-damper system is determined and given as a reference input to the system. The feedback controller is constructed so that the fine stage tracks the coarse stage errors. The controller is robustly designed as the “perturbation compensated sliding mode control” law, which is a combination of sliding mode controller and perturbation observer. In addition, a null motion controller which regulates the fine stage at its neutral position is designed based on the “dynamic consistency” and, as a result, the overall dual-stage servo system exhibits robust and time-optimal performance. The inherent merit and performance of the dual-stage system is shown by experiments