Design and Torque Analysis of a Lead-Free Piezoelectric Ring-Shaped Traveling Wave Ultrasonic Motor

Lead-free piezoelectric materials have excellent environmental friendliness and are more suitable for the environmental requirements of artificial intelligence actuators. Considering environmental protection, a ring-shaped traveling wave ultrasonic motor based on 0.80Na<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>Bi<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>−0.20K<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>Bi<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> lead-free piezoelectric ceramic was designed using finite element analysis software. Then, to calculate the torque of USM, a contact model considering driving and braking forces was established based on friction theory. A model based on driving conditions and stator structure parameters can estimate the torque of a circular traveling wave ultrasonic motor. Finally, the output torque of the lead-free motor was calculated using a contact model. The results indicate that the calculated output torque based on the contact model is in good agreement with the measured values. The article also analyzed the reasons for the deviation between the calculated values and the measured values.