A comparison of dithers for hysteresis alleviation in dahl model based piezoelectric actuator

Hysteresis is a major impediment in achieving precise position tracking through piezo actuated micro nano manipulator. In our study it has been shown that the effect of hysteresis can be mitigated by the proper application of a suitably selected dither sequence. The objective of the paper is to compare the various types of dither viz, Sinusoidal, Gaussian, Rayleigh and Rician, as to which gives the optimal system performance in terms of two tests- tracking error and area under the hysteresis curve. This paper starts with the analysis of a piezoelectric actuator based on the Dahl model. An inverse Dahl model based feed-forward mechanism in conjunction with a feedback control is used for the study of the actuator´s performance. Dither injection is applied at three different places in the system and accordingly three different schemes namely displacement dither, voltage dither and combined dither have been developed and compared. Based on the simulations, the best type of dither and its corresponding intensity for a given place of dither injection has been established. Results ascertain dither based control as a simple and an efficient algorithm capable of providing very accurate micro-nano positioning.