• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1115-1119
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• 1996

The objective of this paper is to study on the idle speed control sing the fuzzy logic controller under load disturbance. The inputs of the fuzzy controller are error of rpm and rpm variation. The output of fuzzy controller is an ISC motor step. The airflow is controlled by the ISC motor movement and the idle speed is controlled by the airflow control. During the control, air to fuel ratio was checked by LAMBDA sensor. All experiments were carried in real vehicle.

• Tribology and Lubricants
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• v.15 no.1
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• pp.108-115
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• 1999

The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.

• Physical Therapy Korea
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• v.12 no.4
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• pp.7-11
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• 2005

The purposes of this study were to investigate the effects of variability of training on the acquisition of motor skill of closed loop type tracking task using Rotary Pursuit, and to determine if there was a bilateral transfer effect to the non-dominant hand following practice with the dominant hand. Twelve healthy volunteer students (5 males and 7 females, aged 25 to 37) were randomly divided into a constant practice group and a variable practice group. A photoelectric rotary pursuit apparatus with stop clock and repeat cycle timer by Lafayette Instrumentation Co. was used for this study. Rotary pursuit is a closed loop task in which a subject attempts to keep a photoelectric stylus on a lighted target in motion. Subjects performed the clockwise circular pursuit task while standing. Experimental procedure was divided into three sessions, namely, pre-test, training, and post-test. The constant group practiced all 60 trials at 30 rpm. Variable practice group did a varied practice session with 15 trials at speeds of 20 rpm, 26 rpm, 34 rpm, and 46 rpm. No one in either group practiced with their non-dominant arm. A Mann-Whitney test and a Wilcoxon Signed Ranks test were used for statistical analyses. The results of this study showed no different training effect between groups on the post-test with the dominant hand. However, bilateral transfer effect of rotary pursuit task between hands was demonstrated. Possible mechanisms are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.514-520
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• 2001

A 300Wh class flywheel energy storage system using high Tc superconductor bearings(HTC SFES) is being developed by KIMM and KEPRI. HTC SFES consists of a flywheel rotor, superconductor bearings, a motor/generator and its controller, touch-down bearings, vacuum chamber, etc. Stiffness and damping values of superconductor bearings were experimentally estimated to be 67,700N/m and 29Ns/m respectively. The present HTC SFES was designed to have maximum operating speed of 33000 rpm, which is far above 2 rigid body mode critical speeds of 645rpm and 1,275rpm. Leaf-spring type touch-down bearing were utilized to have the system pass safely through the system critical speeds. It has been experimentally verified that the system can run stably up to 28,000 rpm so that HTC SFES is now expected to reach up to its maximum design speed of 33,000rpm without any difficulties. The Halbach array motor & generator has also been proven its effectiveness on transferring electrical energy to a rotaing composite flywheel in kinetic form.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.323-326
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• 1999

In this paper, a windmill type ultrasonic motor operated by single-Phase AC electric field was fabricated, and then torque characteristics were investigated. A metal-ceramic composite component was used as the stator\`s vibrator to generate ultrasonic vibrations. The windmill type ultrasonic motors has only three components; a stator element with two wind-mill shape slotted metal endcaps, a rotor and a bearing. In this parer we measured torque, when stator\`s slot was changed Iron 4, 6, 8. Brass metal was pressed with umbrella-type using metal molt then slot of 3 kind was manufactured. The maximum revolution speed was 388(rpm) in the case of a small ultrasonic motor of 11.35 mm diameter, 8 slot and 1.01 mm thickness. The maximum torque of 0.17 mNm was obtained at a speed of 131 rpm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.79-82
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• 2004

In general, compressors for refrigerators are major noise source in home environment. The vibration originated from a pump of a compressor can make noise through suspension springs and a LDT(Line Discharge Tube). Especially for the inverter motor driven compressor, the vibration is more serious than it of the constant speed compressors. Because the operation frequency range of an inverter motor driven compressor is very wide from 1600 rpm to 4200 rpm. In this paper, we propose the numerical model to reduce vibration by designing weight balancers and grommets. Results for analytical investigations on the exciting force and moment at the pump mass center, weight balancers and exciting frequency variation are presented.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.169-173
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• 2011

This study is about the development of remote controlled bollard using the BLDC motor and ball screw with mechatronics theory. A bollard is composed of the sensor part and the control part. The sensor part is consisted of sensors that detect the locations of a bollard. The role of the control part is adjusting motor speed and power through variable resistance. In order to confirm required performance, the speed of decent and ascent of the bollard, the time and the RPM of BLDC motor were tested according to the variable resistance and the applied load with 10 to $72kg_f$.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1540-1551
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• 2015

The detection of position and speed in BLDC motors without using position sensors has meant many efforts for the last decades. The aim of this paper is to develop a sensorless technique for detecting the position and speed of BLDC motors, and to overcome the drawbacks of position sensor-based methods by improving the performance of traditional approaches oriented to motor phase voltage sensing. The position and speed information is obtained by computing the derivative of the terminal phase voltages regarding to a virtual neutral point. For starting-up the motor and implementing the algorithms of the detection technique, a FPGA board with a real-time processor is used. Also, a versatile hardware has been developed for driving BLDC motors through pulse width modulation (PWM) signals. Delta and wye winding motors have been considered for evaluating the performance of the designed hardware and software, and tests with and without load are performed. Experimental results for validating the detection technique were attained in the range 5-1500 rpm and 5-150 rpm under no-load and full-load conditions, respectively. Specifically, speed and position square errors lower than 3 rpm and between 10º-30º were obtained without load. In addition, the speed and position errors after full-load tests were around 1 rpm and between 10º-15º, respectively. These results provide the evidence that the developed technique allows to detect the position and speed of BLDC motors with low accuracy errors at starting-up and over a wide speed range, and reduce the influence of noise in position sensing, which suggest that it can be satisfactorily used as a reliable alternative to position sensors in precision applications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.70-79
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• 2005

In this paper, improvement method of control performance by a full-order observer using reduced-order state equation is proposed in the low speed range. Full-order observer using reduced-order state equation is the motor speed and the disturbance torque observer. The proposed algorithm is very stable in the low speed range about 1.9[rpm]. The disturbance torque in the motor drive system degrades speed control performance in the low speed range. The proposed algorithm estimated both motor speed and disturbance torque. The estimated disturbance torque is used as a feedforward value in output of the speed controller, As a result, it improves the response of load torque in the low speed range(1.9rpm).

• Journal of the Korean Society for Heat Treatment
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• v.36 no.5
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• pp.311-317
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• 2023

An autofilter is a device that removes impurities contained in heavy fuel oil used in diesel engines of ships or power plants, and also automatically removes impurities accumulated in the filter through a reverse washing function. The reducer-integrated motor serves to rotate the filter at low speed to enable reverse automatic cleaning in the autofilter device. To achieve a low speed of 0.65 to 0.75 rpm in a reducer-integrated motor, a small motor that can operate at 97rpm at a rated voltage of 110 V and 112.5 rpm at 220 V is required. Additionally, a large gear ratio of 1/150 is required. To ensure the durability and reliability of these reducers, the strength of the gear must be evaluated at the design stage. In general, there is a limit to evaluating the stress and strain state according to the vibration characteristics acting on each gear in the driving state of the reducer through quasi-static analysis. Therefore, in this study, the operation characteristics of the auto filter's reducer-integrated motor were first analyzed using the rigid body dynamics analysis method. Then, this rigid body dynamics analysis model was extended to a flexible multibody dynamics analysis model to analyze the stress and strain states acting on each gear and evaluate the design feasibility of the gear.