An experiment study on temperature characteristics of a linear ultrasonic motor using longitudinal transducers.

The temperature characteristics of a T-shaped linear ultrasonic motor using longitudinal vibration transducers are reported. When the ultrasonic motor is excited by different voltages, the surface temperatures at the driving foot, PZT ceramic and end cap are tested by a thermal imager for obtaining the thermal characteristics of the motor under no-load condition. PZT ceramic shows the maximum temperature increase. Then, the variations of resonant frequencies, electromechanical coupling factors and mechanical Q-factors versus time, as well as the effect of the temperature on the resonance frequencies, electromechanical coupling factors and mechanical Q-factors, is measured and analysed under the long-term running. It is found that all the resonance frequencies and electromechanical coupling factors decrease as the increase of the temperature, as well as the mechanical Q-factors. In addition, the change of the output speed over temperature is tested and the obtained result shows the trend of decline. This work can provide useful guidelines for the design and optimization of linear ultrasonic motor operating in wide temperature range.