An EMG Control System for an Ultrasonic Motor Using a PSoC Microcomputer

An EMG Control System for an Ultrasonic Motor Using a PSoC Microcomputer

Yorihiko Yano (Nara National College of Technology, Japan)
DOI: 10.4018/978-1-4666-2196-1.ch002
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The author investigated the possibility of developing a myoelectric elbow prosthesis powered by an ultrasonic motor. Ultrasonic motors have some features that make them uniquely suited to powering prosthetics: they deliver high torque under low-speed operation, they are compact in size and they produce no electromagnetic noise. Typically, the threshold-level of an EMG (electromyogram) is adopted as the method for myoelectrically controlling prostheses using a microcomputer. However, this method is not suitable for every prosthesis. Here, the author proposes an EMG control system for a myoelectric elbow prosthesis that uses a PSoC microcomputer combined with an accelerometer to create an ultrasonic motor. The chapter shows that the EMG control system developed by the author effectively controlled the ultrasonic motor.
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Proposed Emg Control System

The proposed EMG control system for an ultrasonic motor is shown in Figure 1. The system is composed of an EMG amplifier, a PSoC microcomputer with an accelerometer, and an ultrasonic motor.

Figure 1.

EMG control system for an ultrasonic motor, using a PSoC microcomputer


EMG Amplifier

An EMG has very low amplitude; therefore, the EMG amplifier will need approximately 500 total gains. We used EMG-025 (Harada Electronic Industry Ltd., Japan) as the amplifier. EMG-025 has two measurement electrodes per 1ch and one GND electrode. The specification of EMG-025 is shown in Table 1(Harada Electronic Industry Limited, 2011).

Table 1.
Specification of EMG-025
Frequency10 Hz – 1000 Hz
Amplitude500 (54dB)
Input VoltageDC1.5V – 3.0V
Current0.7 mA/ch (DC3.0V)

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