A Two-DOF Linear Ultrasonic Motor With High Thrust Force Density and High Power Density Utilizing Torsional/Centrosymmetric-Bending/ Symmetric-Bending Modes
Jiang Wu, Lijun Wu, Rui Song, Jianye Niu, Mingli Xie, Miaoyan Cao, Qiang Zhang, Yixiang Liu, Yibin Li
Abstract
In this article, a new two-DOF linear ultrasonic motor operating in three vibration modes is developed and its capability to exhibit high thrust force density and high power density is tested. Here, the driving force is produced by synchronously exciting the torsional (T) and centrosymmetric-bending (B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) modes, whereas the normal force is generated with the symmetric-bending (B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ) mode. Initially, the T-B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> /B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> hybrid transducer in cross shape is designed through modal degeneration and the working principle is verified by simulation. Subsequently, a 50-mm-high 130-mm-long transducer prototype is fabricated to make the slider movable along two horizontal axes ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> ). Finally, the performance is assessed via experiments. When the voltage is 250 V and the working frequency is ∼21.6 kHz, the motor yielded the maximal thrust force, no-load sliding speed, and maximal output power of, respectively, 84.3 N, 1562 mm/s, and 33.2 W in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -axis; and 86.2 N, 1531 mm/s, and 34.1 W in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -axis. Moreover, the thrust force density and power density reached, respectively, 78.4 N/kg and 31.0 W/kg, exceeding the values of most conventional two-DOF linear ones. This article validates the T-B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> /B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> motor's high actuating capability and also provides a new approach to design powerful two-DOF linear motors.