Low-voltage micro-displacement driving circuit and its control method

The application of a low-voltage micro-displacement driving circuit and its control method on an optoelectronic profilometer are discussed. The low-voltage driving circuit is adopted to drive a piezoelectric ceramic phase shifter to shift the phase of the reference beam, so as to make the instrument lighter, smaller and cheaper. In order to eliminate the nonlinear error in the low-voltage region of the piezoelectric ceramic, the value of the voltage applied on the piezoelectric ceramic is controlled by a PC computer, images are taken by a camera for calculating the intervals between the interference fringes. The value of the voltage is adjusted continually by the PC computer until the phase difference of the interference fringes meets the requirement. The method has several advantages, the nonlinear error in the low-voltage region of the piezoelectric ceramic can be eliminated, the advantage of closed loop circuit can be obtained with the open-loop control circuit and the complexity in assembly of mechanical parts can be reduced.