低压微位移驱动电路及控制方法

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

讨论了低压微位移驱动电路及控制方法在光电轮廓仪上的运用。采用低压驱动电路驱动压电陶瓷相移器对参考光束进行相移,从而使仪器质量减轻、体积缩小、成本降低。在运用该电路时,为了解决压电陶瓷低电压区非线性误差大的问题,用PC计算机控制压电陶瓷上所加电压的电压值,由摄像头摄取图像并计算出干涉条纹的间隔,然后由PC计算机修改压电陶瓷上所加的电压值,直至干涉条纹相位差达到要求值。该方法的优点是:可消除压电陶瓷低压区的非线性误差,使得开环电路得到闭环的效果;可降低机械零部件的装配难度。

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.