• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.377-396
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• 2000

After warming-up exercise for 20 minutes, Isokinetic measurement of trunk strength for flexor and extensor was done by using Cybex 6000 TEF Unit on 91 healthy male white workers from 22years old to 49 years old, and compared each other. 20 repetitions of trunk extension-flexion were done at $120^{\circ}$/sec angular velocity. After resting for 1 minutes, Four repetitions at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) were done with 30 seconds of resting interval between each angular velocity. The purpose of this study is to obtain the isokinetic normative strength values for trunk extensors and flexors, and is to know the correlation between age, height, weight of subjects and data from isokinetic trunk strength measurement, and is to provide a guideline for exercise program of male white collar workers The collected data were analyzed by ANOVA, Duncan's Multiple Range Test, and Pearson correlation coefficiency in PC-SAS program. The results obtained were as follow; 1. There is significant positive-correlation with the statistic value between weight and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec)(p<01), between height and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) except peak torque of trunk flexor at $60^{\circ}$/sec(p<01). 2. There is nagitive-correlation between age and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec), there is significant differences with statistic value between age and peak torque of trunk extensor at $120^{\circ}$/sec(p<.01). 3. Mean peak torque and mean peak torque % by body weight of trunk extensor is 1.1 times higher values than trunk flexor at $60^{\circ}$/sec. 4. There is the increase in peak torque angle of trunk flexor with increasing of age, and the decrease in peak torque angle of trunk flexor with increasing of age at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec). there is significant differences with statistic value in peak torque angle of trunk flexor at $120^{\circ}$/sec(p<.01). 5. There is significant decrease in endurance ratio of trunk extensor with increasing of age at $120^{\circ}$/sec(p<.01). In conclusion, peak torque of trunk extensor is 1.1 times higher values than trunk flexor in healthy male white collar workers.

• Journal of Astronomy and Space Sciences
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• v.28 no.4
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• pp.311-317
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• 2011

Momentum changing actuators like reaction wheels and control moment gyros are generally used for spacecraft attitude control. This type of actuators produces force and torque disturbances. These disturbances must be reduced since they degrade the quality of spacecraft attitude control. Major disturbances are mainly due to static and dynamic imbalances. This paper gives attention to the reduction of the static and dynamic imbalance. Force/torque measurement system is used to measure the disturbance of the test reaction wheel. An identification method for the location and magnitude of the imbalance is suggested, and the corrections of the imbalance are performed using balancing method. Through balancing, the static and dynamic imbalance is remarkably reduced.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.63-70
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• 2018

In this paper, the design of a novel 6-axis compliance device with force/torque sensing capability and the experiment results on force measurement are presented. Unlike the traditional control methods using a force/torque sensor with very limited compliance, the force control method employs a compliant device to provide sufficient compliance between an industrial robot and a rigid environment for more stable force control. The proposed compliance device is designed to have a diagonal stiffness matrix at the tip and uses strain gauge measurement which is robust to dust and oil. The measurement circuit is designed with low-cost IC chips however the force resolution is 0.04N.

• Bulletin of the Korean Space Science Society
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• 2005.04a
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• pp.138-142
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• 2005

A reaction wheel, an actuator for satellite attitude control, produces disturbance torque and force as well as its axial control torque. The disturbances have an influence on the pointing stability of high precision satellites. The measurement of disturbances for such a satellite, therefore, is necessary. The wheel's rotation, however, causes the vibration of the table and its vibration induces measurement errors, especially large near the resonance frequency of the Measurement table. For the purpose of overcoming these defects, a calibration method using frequency compensation is suggested in this paper. Disturbance parameters are identified from data examined by frequency compensation. Measurement frequency range can be expanded far higher than the resonance frequency, since the degradation of data accuracy caused by its vibration is well alleviated even in the resonance area.

• The Journal of Korea Robotics Society
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• v.13 no.1
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• pp.55-62
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• 2018

In this paper, a method for estimation of external force on an end-effector using joint torque sensor is proposed. The method is based on portion of measure torque caused by external force. Due to noise in the torque measurement data from the torque sensor, a recursive least-square estimation algorithm is used to ensure a smoother estimation of the external force data. However it is inevitable to create a delay for the sensor to detect the external force. In order to reduce the delay, modified recursive least-square is proposed. The performance of the proposed estimation method is evaluated in an experiment on a developed six-degree-of-freedom robot. By using NI DAQ device and Labview, the robot control, data acquisition and The experimental results output are processed in real time. By using proposed modified RLS, the delay to estimate the external force with the RLS is reduced by 54.9%. As an experimental result, the difference of the actual external force and the estimated external force is 4.11% with an included angle of $5.04^{\circ}$ while in dynamic state. This result shows that this method allows joint torque sensors to be used instead of commonly used external sensory system such as F/T sensors.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.11-18
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• 2013

For a reliability assessment of machinery parts, accurate performance test, environmental test, life test, etc. are required on the sample. In the performance test conditions of various machinery parts, some problems happen such as needs to rise temperature rapidly with large flow of oil having very low thermal conductivity and to measure very high torque or tiny torque, etc. This study brings out the method to apply heat to rise temperature for large flow of oil without chemical change in a performance test of oil cooler. To measure large scale of torque in a performance test of planetary gearbox of excavator, the method of torque measurement is proposed by replacing the large torque meter priced very expensive. To measure very small torque on lubricated friction, a methode of force balance type test mechanism is introduced for tests of piston assembly.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.223-231
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• 2003

Statement of problem : Little is known about the effect of a counter-torque device and the internal hexagon of abutment on the tightening torque transmitted to the implant. Purpose : The purpose of this study was to examine the effect of a counter-torque device and the internal hexagon of abutment on the tightening torque transmitted to the implant. Material and Methods : In this study, three types of abutment were used, (1) two-piece conical abutment with hexagon, (2) two-piece conical abutment without hexagon, and (3) one-piece conical abutment without hexagon. The experimental groups were divided into five groups according to the type of abutment and the usage of a counter-torque device. Group I : two-piece conical abutment with internal hexagon was tightened without the use of a counter-torque device. Group II : two-piece conical abutment without internal hexagon was tightened without the use of a counter-torque device. Group III : one-piece conical abutment without internal hexagon was tightened without the use of a counter-torque device. Group IV : two-piece conical abutment with internal hexagon was tightened with the use of a counter-torque device Group V : two-piece conical abutment without internal hexagon was tightened with the use of a counter-torque device. Abutments were tightened 20Ncm torque with the use of manual torque wrench and then torque values were measured by torque-gauge. After the measurement of torque values, all groups were loosened with the use of manual torque wrench and then detorque values were measured by torque-gauge. Results : The results were as follows. 1. There were no differences in torque values among three types of abutment. 2. Regardless of the existence of the internal hexagon of abutment, a counter-torque device decreased the tightening torque transmitted to the implant about 92% 3. In group III showed the highest detorque value, however there were no differences among group I, II, IV and V. Conclusion : Within the limitations of this study, it was concluded that the internal hexagon of abutment has no effect on the tightening torque transmitted to the implant and the detorque value of abutment screw. The use of a counter-torque device is essential to prevent microfracture on the implant-bone interface but has no effect on preload.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.187-188
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• 2008

An ultrasonic motor of high torque with a new configuration for application in automobiles is proposed. The newly designed stator is a two sided vibrator consisting of a toothed metal disk with a piezoelectric ceramic ring bonded on both faces of the disk which generates a flexural traveling wave along the circumference of disk. In this configuration, the displacement on the surface of stator may not be confined. It also produces a large vibrating force and amplitude because the vibrator is sandwiched by two piezoelectric plates. It is possible to increase the torque by improving the vibration characteristics. To compute the vibration mode of the motor of diameter 48 mm, the finite element method was used. A 6th mode was chosen as the operation mode with a resonance frequency of about 64.4 kHz. According to this design and measured its performance, a prototype was fabricated. The performance measurement of the prototype motor showed that its stall torque was about 1.8 Nm and efficiency was 37% at 60% of the maximum torque.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.414-419
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• 2015

Recently, commercial ships and other specialized vessels with electric propulsion system employ variable speed induction motor as its prime mover. The wide application of electrical motors also includes being the main drive system in most industrial machineries. However, during its start-up, shutdown, and brake switch operation, excessive torque variation are generated. As such, flexible coupling are installed in order to reduce the transmitted torque fluctuation to the driven side. In this paper, the pulse torque generated by an variable speed induction motor was analyzed theoretically and through measurement of torsional vibration. Induction motor with inverter on marine propulsion system and industrial compressor were used as experimental subjects. The study confirmed that pulse torque are generated regardless of motor speed and interpreted as a vibration source of the whole system. Results presented herein can be adopted as the basis in future amendment of inspection classifying body regulations.

• Physical Therapy Rehabilitation Science
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• v.12 no.2
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• pp.201-205
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• 2023

Objective: Resistance exercise is a necessary element to improve quality of life, and measurement and evaluation of muscle strength provide important information for prescription and management of rehabilitation and exercise programs. This study analyzed the correlation between direct and indirect 1RM for isokinetic maximum torque of the knee joint in order to provide useful information in the field of exercise programs. In addition, the flexion-extension ratio and the difference in left-right deviation were verified. Design: A cross-sectional study Methods: The subjects of this study were 33 healthy adult men and women without medical problems who participated in the health exercise class program at S University in Seoul. The correlation between isokinetic maximum torque and direct and indirect 1RM was analyzed, and a dependent t-test was performed to analyze the flexion-extension ratio and left-right deviation. Results: There was a high correlation between the isokinetic maximum torque and direct and indirect 1RM, and no statistically significant difference was shown between the test methods in the analysis of the flexion-extension ratio and left-right deviation. Conclusions: Isokinetic muscle function measuring equipment is expensive, so it is difficult to use it in local exercise rehabilitation and training sites. Through this study, it was found that direct and indirect 1RM isokinetic maximum torque showed a high correlation, and there was no difference in evaluating muscle function such as flexion-extension ratio and left-right deviation. Therefore, it is considered that the muscle function evaluation using 1RM in general field can be usefully utilized.