超音波モータを使用したダイレクトドライブマニピュレータの制御

Abstract

The traveling wave ultrasonic motor (USM) has many good characteristics that is compact size, light weight, low speed rotation, high speed response and silent motion. The many characteristics are good for the direct drive manipulator, but it is not easy to control the speed and torque of the USM from zero to the maximum value continuously by the usual method. So we have developed a new method for the torque and speed control system for the USM, and also developed a compact size light weight direct drive manipulator, which use the USM for the actuators. The manipulator has two vertical axis joints and moves in the horizontal plane. The torque and speed of the USM were controlled by the phase difference of the two-phase driving signals of the motor. To realize the contact tasks by the compact size and light weight manipulator, we developed the control system that the actuator has the characteristics of compliance and damping in itself. The adjustable compliant motion was realized by the feedback of the output shaft angle and angular velocity of the output shaft. It is realized that the compliant motion likes a dash pot with spring. With the compliance control, some contact tasks were carried out.