• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.64-71
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• 2006

In this paper, a uniform speed controller for an ultrasonic rotary motor is developed using the phase-difference method. The phase difference method uses traveling waves to drive the ultrasonic motor. The traveling waves are obtained by adding two standing waves that have a different phase to each other. A compact phase-difference driver system is designed and integrated by combining VCO(Voltage Controlled Oscillator) and phase shifter. Theoretically the relationship between the phase difference in time and the rotational speed of the ultrasonic motor is sine function, which is verified by experiments. Then a series of experiments under various loading conditions are conducted to characterize the motor's performance that is the relationship between the speed and torque. Proportional-integral control is adopted for the uniform speed control. The proportional control unit calculates the compensating phase-difference using the rotating speed which is measured by an encoder and fed back. Integral control is used to eliminate steady-state errors. Differential control for reducing overshoot is not used since the response of ultrasonic motor is prompt due to its low inertia and friction-driving characteristics. The developed controller demonstrates reasonable performance overcoming disturbing torque and the changes in material properties due to continuous usage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.149-154
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• 2020

This paper presented a design and a implementation of prototype model which is the smart diffuser device controlled by using Bluetooth technology in the smart phone. We used the ultrasonic waves oscillator so that the smart diffuser was able to spray oil into a device. The device was developed to find out the high brightness led colors switched during spraying the oil. By using the Li-Po battery of 40mAh capacity, we were able to design this portable device was prolonged available time to use and to solve the charging time problem. We realized the availability of prototype model which is using the Bluetooth Low Energy for operating the low power driving.