Adaptive and repetitive control of a fast tool servo for precision motion control

The research in this dissertation investigates adaptive and repetitive control algorithms for tracking precise dynamic motion profiles and rejecting board-band disturbances. Experimental results for several precision motion control applications are demonstrated to confirm the effectiveness of the adaptive and repetitive control approaches. A fast tool servo (FTS) has been designed and fabricated for machining fine surface textures. Two control algorithms are developed and implemented on the FTS. The first algorithm integrates robust feedback, optimal feedforward, repetitive controls and adaptive disturbance canceller in a way that each control action can be designed separately but achieve synergistic performance collectively. This first algorithm is applied to the FTS for tracking a high frequency scanning profile under stochastic disturbances. Implementation issues such as inter-sample errors and digital filtering sensor noise are presented for this high bandwidth, nano-resolution digital control system. The second algorithm is a direct design approach which integrates feedforward, feedback, and repetitive control into adaptive control in a unified framework. This second algorithm has been applied to the FTS for tracking a complex profile with multiple frequency components, a hard disk drive track following control under repeatable and non-repeatable runouts, and laser beam control for tracking periodic trajectories under stochastic disturbances.