Jahantab Seyed Hassan, Hojjat Yousef, Ghavami Namin Behzad, Shirkosh Mohammad
Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
Sci Rep. 2023 Jul 24;13(1):11910. doi: 10.1038/s41598-023-39111-8.
The present study introduces a multi-degree-of-freedom (MDOF) ultrasonic motor, which is capable of driving a spherical rotor using spiral wire stators and a piezoelectric stack actuator. Wire stators and piezoelectric stack actuators enable the proposed motor to be smaller and simpler, lower in power consumption, and have different modes at different frequencies. In this motor, two wire stators are used to drive the spherical rotor and rotate it in different directions. The eigenfrequency and frequency domain analyses were carried out using the finite element method (FEM) to evaluate the MDOF capability of the motor in different vibration modes. It has been demonstrated that the piezoelectric stack actuator can provide MDOF motions through its vibration modes. The resonant frequency obtained by the frequency domain approach agreed with the impedance analyzer test. Rotational speed, torque, and preload force were experimentally investigated. Using shear stress caused by viscous fluid in contact with the spherical rotor, a new torque calculation method was developed. Based on the buoyancy force exerted on the immersed rotor, the preload force was measured. The experimental results indicated that the maximum rotational speed of the spherical rotor was 306 rpm, and the maximum torque was 4.7 μN m.
本研究介绍了一种多自由度（MDOF）超声波电机，该电机能够使用螺旋线定子和压电叠层致动器驱动球形转子。线定子和压电叠层致动器使所提出的电机体积更小、结构更简单、功耗更低，并且在不同频率下具有不同模式。在该电机中，两个线定子用于驱动球形转子并使其沿不同方向旋转。使用有限元方法（FEM）进行了固有频率和频域分析，以评估电机在不同振动模式下的多自由度能力。结果表明，压电叠层致动器可以通过其振动模式提供多自由度运动。通过频域方法获得的共振频率与阻抗分析仪测试结果一致。对转速、扭矩和预紧力进行了实验研究。利用粘性流体与球形转子接触产生的剪切应力，开发了一种新的扭矩计算方法。基于施加在浸没转子上的浮力，测量了预紧力。实验结果表明，球形转子的最大转速为306转/分钟，最大扭矩为4.7微牛顿米。
