| 摘要 |
PURPOSE:To always drive a piezoelectric vibrator used in a piezoelectric motor or the like at constant amplitude. CONSTITUTION:In a pulse width modulating part A, the oscillation output with predetermined frequency from an oscillation part 15 is modulated in its pulse width by the control power obtained from a CPU 25 through a D/A conversion part 26 and the vibrator 2 for twist vibration and vibrator 4 for longitudinal vibration of a piezoelectric motor 10 are driven by this driving power to rotate a rotor 6. The power based on the amplitude difference of the piezoelectric vibrator 2 is taken out by the bridge circuit of a vibration detecting part F to be negatively fed back to a differential amplifier 18 to obtain pulse width modulating control power E1. By modulating pulse width by the power E1, the vibrator 2 is always driven at constant amplitude and the motor can be driven in the constant number of rotations. |
