Dither based precise position control of piezo actuated micro-nano manipulator

This paper addresses the problem of hysteresis and presents a new control scheme for hysteresis compensation of piezo-electrically actuated micro-nano manipulators. The technology employs an Inverse Dahl model based feed-forward mechanism in combination with a feedback control algorithm along with simultaneous voltage and displacement dither strategy. The actuator performance is seen to improve as a function of injected noise level into the plant- a phenomenon known as dithering. The notion of stochastic resonance for nano positioning is studied to determine the optimal dither level for efficient plant performance. The efficacy of the proposed control scheme has been confirmed through rigorous simulations in terms of two specific tests- a) tracking error test and b) hysteresis curve area test. Results show an enhanced positioning precision of the manipulator with the proposed dither control than without it. Owing to its algorithmic simplicity, the proposed control genre can be extended to the parlance of other nano-scale applications.