Velocity Control of Traveling-Wave Ultrasonic Motors Based on Stator Vibration Amplitude

Abstract

Nonlinearity and resonance frequency shift make it difficult to control the operation of the traveling-wave ultrasonic motors (TWUSMs) in a wide velocity and load range. In this paper, a velocity control scheme based on the stator vibration amplitude and the parallel resonance frequency (VCBVF) of TWUSMs is proposed. Then, the stator vibration amplitude (SVA) and parallel resonance frequency (fp) are detected by a transformer ratio-arm bridge. Based on the linear relationship between the velocity and the SVA of TWUSMs, the proposed scheme achieves the control of the mechanical loop and the electrical loop. The linear relationship between the velocity and the SVA makes the mechanical loop achieve the target velocity efficiently, according to the SVA, and the electrical loop could provide the target SVA quickly. Experimental results show that the response time of velocity is 3–4 ms under different load torques and the overshoot is less than 22%. In addition, the proposed scheme improves the efficiency of TWUSMs due to fp tracking. Due to directing the SVA control, the proposed scheme can heighten the velocity response and the load adaptability of TWUSMs, and promote the application of TWUSMs under various conditions.

Speed Sensorless Control of Linear Ultrasonic Motors Based on Stator Vibration Amplitude Compensation

“…The working principles of LUSMs and rotary ultrasonic motors are similar, so in order to achieve the VBSC, a transformer ratio arm bridge (TRAB) is used to detect the SVA [ 19 ]. The parallel equivalent circuit model of the single-phase PZT ceramic of the LUSM and the schematic diagram of the TRAB are shown in Figure 2 .…”

“…However, for LUSMs, the slider position change is not associated with the input voltage, so this method is not suitable for LUSMs. Fang et al [ 19 ] found that the transformer tap voltage of the transformer ratio arm bridge is linear to the rotor speed of the rotary ultrasonic motor. Therefore, the rotor speed can be estimated according to the transformer tap voltage.…”

A Driving and Control Scheme of High Power Piezoelectric Systems over a Wide Operating Range

“…For model A, which is similar to the classic Butterworth-Van Dyke (BVD) model [ 20 , 21 ], the series , and characterize the modal damping, mass and stiffness, respectively. Under the steady state of sinusoidal excitation, the model A can be converted to the model B [ 19 ]. In this model, the parameters can be calculated by where …”

“…However, these schemes require complicated software operations to calculate the frequency deviation and the vibration amplitude. With the aid of a transformer ratio arm bridge (TRAB), a vibration amplitude signal is obtained online in an ultrasonic motor control scheme under different operating conditions [ 19 ]. Moreover, this signal is in phase with the excitation current at , so the parallel resonance detection can be achieved by detecting the phase between the vibration and the excitation current signals.…”

A Review of Application and Development Trends in Ultrasonic Motors

“…[26,27] Recently, there have been breakthroughs in the open-loop control technology of ultrasonic motors, which carry great significance for some applications in which it is difficult to develop closed-loop control, such as cell slice actuators, ear surgical equipment, and magnetic compatible tactile interfaces. [28][29][30][31] In this paper, application of ultrasonic motors in aerospace, optical, biomedical, and precision engineering is surveyed. Some technological breakthroughs and corresponding problems caused by new materials and technologies are then discussed.…”