Control system for multiple joint robotic arm powered by ultrasonic motor

This paper reports on a new type of system configuration that allows for multiplexed operation of Ultrasonic Motors (USM). This system consists of a control board and a multiplexer board paired with each USM. The control signal from the controller board sends an address signal to the multiplexer board to enable or disable the ground return link for the motor. The piezo-deflection amplitude from the addressed USM is then connected to the controller board. Each motor is connected in parallel with the power bus. The controller board consists of a microcontroller, a field programmable gate array, a digital frequency synthesizer, a push-pull converter and a hardware interface that allows the user to change control parameters through a LABVIEW graphic user interface. Experimental results confirm that the strategy allows the user to control a number of Shinsei USM60 ultrasonic motors in a sequential fashion.