• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.151-157
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• 2006

The passenger car drivers want in general to feel good driveability, but they sometimes feel uncomfortable by shock and jerk phenomena when they push or release acceleration pedal with clutch on state. In this paper, the shock and jerk characteristics are studied on the vehicles controlled by the throttle-by-wire system. Experiments and simulations were carried out on two vehicles which show different control characteristics. The engine torque control characteristics was analyzed by measuring cylinder pressure. Various specification factors of the vehicles and the torque control logic of the engines were simulated through experimental data basis. The result shows the spring effect of the trans-axle in the drive-train is one of the most important factors of the shock-jerk phenomena and the engine torque control method is also responsible for the reducing the shock-jerk amplitude. In this paper a new control logic of the engine torque is suggested for the better driveablility on the tip-in/out event.

• The Journal of Korean Physical Therapy
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• v.23 no.6
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• pp.37-42
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• 2011

Purpose: The aim of this study is to suggest the basic materials for proposing effective and efficient methods when stretching by measuring isokinetic muscular strength according to static, dynamic and PNF stretching. Methods: This study was conducted on 45 healthy persons (male and female) in their twenties who are attending universities. The subjects are randomly divided into three (3) groups, and static stretching is applied in group 1, dynamic stretching is applied in group 2 and PNF stretching is applied in group 3. After carrying out static, dynamic and PNF stretching, peak torque was measured using isokinetic muscular strength measurement. Results: According to the results, at $60^{\circ}$/sec and $180^{\circ}$/sec isokinetic peak torque of the knee joint according to types of stretching, the largest changes were shown in Group 2 extension and flexion, and the least changes were shown in Group 1. There were significant differences among the three groups (p<0.05), and the result of after-analysis by LSD showed that there were significant differences between Groups 1 and 2, and Groups 1 and 3 (p<0.05). Conclusion: The intention of this study was to determine the peak torque using Cybex after applying three stretching methods to hamstring muscles, and the case of dynamic and PNF stretching was found to be more significant in both the $60^{\circ}$/sec and $180^{\circ}$/sec angular speeds than that of static stretching. Using the results of such studies, if dynamic and PNF stretching are applied together with warming-up before performing sports, the risk of suffering wounds would reduce and the exactness of sports would increase.

• Journal of Space Technology and Applications
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• v.4 no.1
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• pp.12-26
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• 2024

Attitude control of a satellite is very important to ensure proper for mission performance. Satellites launched in the past had simple missions. However, recently, with the advancement of technology, the tasks to be performed have become more complex. One example relies on a new technology that allows satellites quickly alter their attitude while orbiting in space. Currently, one of the most widely used technologies for satellite attitude control is the reaction wheel. However, the amount of torque generated by reaction wheels is too low to facilitate quick maneuvers by the satellite. One way to overcome this is to implement posture control logic using a control moment gyroscope (CMG). Various types of CMGs have been applied to space systems, and CMGs are currently mounted on large-scale satellites. However, although technological advancements have continued, the market for CMGs applicable to, small satellites remains in its early stages. An ultra-small CMG was developed for use with small satellites weighing less than 200 kg. The ultra-small CMG measured its target performance outcomes using a precision torque-measuring device. The target performance of the CMG, at 800 mNm, was set through an analysis. The final torque of the CMG produced through the design after the analysis was 821mNm, meaning that a target tolerance level of 10% was achieved.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.388-394
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• 1998

We designed and fabricated an improved null-type torque magnetometer for measuring magnetic anisotropy of magnetic materials. This torque magnetometer has a measurement range of $~{\pm}15$ dyne.cm, and the range can be controlled. Resolution is ~0.0005 dyne.cm. Noise level is less than 0.01 dyne.cm with one measurement, and less than 0.004 dyne.cm with 10 averaged measuremets. The precision is less than 0.5 %. In contrast to typical null-type torque magnetometers, we placed a small ferrite magnet in the Helmholtz coil, instead of placing coil in the permanent magnet. From this novel sturucture, we can design a geometrically isotropic and relatively light-weight sample rod. Also, we can prevent the effect of input and output lines of coil exposed in the magnetic field in torque meter. Consequently, our novel null-type torque magnetometer can have a better sensitivity, faster response time, and smaller distortion of torque curve than commercially available torque magnetometers.

• Journal of the korean Society of Automotive Engineers
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• v.4 no.3
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• pp.48-55
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• 1982

In the present the strain gauge type torque transducers consist of solid shaft as sensor, slip ring, brush and bridge circuit as detecting circuit. So in the case of measuring the low-capacity torque, the error caused by technical mistake in mounting stain gauge on the small sensor and especially by contact resistance between slip ring and brush takes place more than the large sensor. Therefore in this study constant voltage in order to have no effect of contact resistance is supplied to the hollow shaft and Schrobron Bridge Circuit. Through the experiment good results were obtained as follows; linearity, hysterisis and zero drift as static characteristics is within 1% F.S respectively. Also when loading, zero drift is about 2% F.S.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.276-280
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• 1996

This paper presents an indirect method for on-line measuring the cutting forces in contour NC milling processes by using the current signals of the servo drive motors. A Kaluman filler is used for estimating each of the load torques to the x, y-axis servo motors of a horizontal machining center. Then, the load torque induced by the friction force in the guidewayis estimated and subtracted from the total extermal torque, thus resulting in the load torque induced by the cutting force. A series of experimental works on the circular interpolated contour milling process shows good agrement between the cutting forces measured by the dynamometer and those estimated by the method presented in the paper.

• Journal of ILASS-Korea
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• v.7 no.1
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• pp.1-6
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• 2002

This study has focused on using fuel injections as variables for measuring performance and reducing exhaust gas in turbo-charger diesel engine. In experiments, we changed nozzle hole diameter, diameter of an injection pipe, and injection timing as variable. The results show that torque. fuel consumption and smoke are reduced as nozzle hole diameter decreases, while NOx increases. When the diameter of injector is reduced, torque, fuel consumption and smoke are deteriorated, but NOx is decreased. In addition, when the time for injection is advanced. torque, fuel consumption and smoke are improved, but the density of NOx is increased.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.15-19
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• 2000

The main advantages of DSPSRM lie in the simple robust construction, low manufacturing cost and simple driving circuit. Especially, it is possible to make shortly the axial length of DSPSRM. therefore, it is suitable to setup this motor in a narrow space. For practical use, prototype of DSPSRM was already manufactured. In this paper, we explain driving method and design driving circuit of DSPSRM. And then speed, torque and efficiency are measured. As a result of measurement, the torque was constant at normal speed and the speed was linearly increased as the current increase. Therefore, we verify that DSPSRM is suitable for low-speed fan load.

• Proceedings of the KIEE Conference
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• summer
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• pp.989-991
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• 2004

There are many elements that affect the average torque of the single phase SRM. It is related with the stator and rotor pole arcs, the dwell angle of the exciting current, the turn on/off angle, etc., Most of all, the turn on/off angle is affect the design procedure of the driving and control circuit. So, in this study, it is intend to analyze the effect that the variations of the turn on/off angle affects the average torque. and then this analyses will be used to design the control driver of the single phase SRM.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.289-293
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• 2004

In the present study, knee varus torque and mediolateral accelerations were measured using the three-dimensional motion analysis system and a linear accelerometry in odor to determine the effect of heel wedges during walking. Wedges were inclined with 10$^{\circ}$ and 15$^{\circ}$ in medial and lateral directions respectively Both knee varus torques and mediolateral accelerations showed two distinct positive peaks in loading response and preswing. Medial wedges resulted in significantly increased both knee varus torque and lateral acceleration in loading response, compared with the barefoot walking(p<0.05). On the other hand, lateral wedges decreased them in loading response(p<0.05). This became more significant for more inclined wedges. However, no significant correlations were found between knee varus torque and lateral acceleration according to the angle of heel wedges in preswing. From this study, it was found that a lateral wedge would be helpful to treat osteoarthritis, decreasing knee varus torque in loading response. In addition, lateral acceleration of the knee joint might be an alternative to determine the effect of wedges and the alignment of the knee joint during walking, instead of measuring knee torque by the three-dimensional motion analysis.