Adaptive sinusoidal disturbance cancellation strategy for pointing applications

This paper combines an adaptive sinusoidal disturbance cancellation scheme with linear pointing control techniques. The approach utilizes a six-axis active platform to reject disturbances with a large sinusoidal component, which could be caused by a noisy host or target. Since often the frequency of the sinusoidal disturbance can not be precisely known, a phase locked loop (PLL) algorithm is used to catch the frequency, and a method for PLL design is developed. Experimental results on the UW (University of Wyoming) hexapod demonstrate a 50-fold decrease in pointing errors due to the monotone disturbance