Stepping Control Method of Linear Displacement Mechanism Driven by TRUM Based on PSoC

A method based on programmable system-on-chip (PSoC) is proposed to realize high resolution stepping motion control of liner displacement mechanism driven by traveling wave rotary ultrasonic motors (TRUM). Intelligent controller of stepping ultrasonic motor consists of PSoC microprocessor. Continuous square wave signal is sent out by the pulse width modulator (PWM) module inside PSoC, and converted into sinusoidal signal which is essential to the motor's normal working by power amplifier circuit. Subsequently, signal impulse transmission is realized by the counter control break, and the stepping motion of linear displacement mechanism based on TRUM is achieved. Running status of the ultrasonic motor is controlled by an upper computer. Control command is sent to PSoC through serial communication circuit of RS-232. Relative program and control interface are written in LabView. Finally the mechanism is tested by XL-80 laser interferometer. Test results show that the mechanism can provide a stable motion and a fixed step pitch with the displacement resolution of 6 nm.