• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.298-306
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• 1993

A portable torque and power measurement system for small farm equipment based on instrumented pulley was developed. The prototype pulley was machined from mild steel, with spokes serving as strain beams. Strain gages mounted to the spokes sense the bending strain due to the torque and convert this into millivolt output. Calibration results showed the torque-millivolt relationship was linear, while hysterisis and error were less than 1% fs. For power measurements, an additional tachmeter with dcvoltage output is necessary. With the tachometer , error in power measurement was +-1.03W or 0.2% fs. Field tests showed that for ease of installation, no machine alteration needed and safety, this system had advantage over other methods for small farm equipment.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.184-193
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• 2001

In vector control technique, stator currents of an induction motor are transformed to equivalent d-q currents in a reference frame consist of d and q axis, each of which is coincide with flux and torque direction respectively. Since the current in q-axis is related to the torque in a synchronously rotating frame, torque is estimated as a function of q-axis current and flux. In this paper, a method to estimate torque of an induction motor based on the measurement of 3-phase currents and rotating velocity of a rotor is presented. Graphic-programming is used to measure signals, to estimate the torque and to show the result in the form of user friendly graph in window environment. To stabilize the fluctuation of estimated torque caused from the small measurement error of the rotor velocity, the stator current is reconstructed in a program based on measured signals. The experimental results executed under the velocity of 500 rpm, 1500 rpm without load and 1500 rpm with load show that the proposed method estimates the torque very well.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1204-1208
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• 1991

This paper describes the 2-channel telemeter system using AM(Amplitude Modulation) - FM (Frequency Modulation) techniques suitable for measurement of spindle torque by strain gage. In order to evaluate the developed system, the model tests were performed for test specimens. The developed system was installed on the plate mill and it was possible to measure and analyze the torque signal of spindle,

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.1-8
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• 1991

This study was carried out to evaluate indirect methods of engine torque measurement. Three indirect methods based on throttle valve opening, exhaust gas temperature and inlet air pressure were compared. The indirect method based on throttle valve opening appeared to be the most satisfactory in terms of accuracy and response time. The discrepancies between the direct method and the indirect method based on throttle valve opening in measuring engine torque were 2% on t he average.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.185-190
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• 2015

This paper presents a new method to determine sensitivity coefficients of temperature and humidity of torque transducers by using a natural and seasonal variation of ambient conditions at the laboratory. We had measured the sensitivities of the torque transducers over almost one year using the KRISS 2 kN m torque standard machine. The sensitivity data acquired at various ambient conditions were processed using our measurement model to extract the sensitivity coefficients of temperature and humidity simultaneously with high precision. A comparison with a previous method using an environmental control chamber was carried out to test the feasibility of using our new method. Two results agreed within the uncertainty. We revealed that the torque measuring errors could be 8 times higher than the measurement and calibration capability of KRISS torque standard machine if the sensitivity changes due to the temperature and humidity are not properly corrected during a calibration.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.218-222
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• 2011

This paper proposes a single-joint optical torque sensor with one body structure. Conventional optical torque sensors consist of three parts, two plates and an elastic structure. They have slightly slipping problem between plates and elastic structure due to the manufacturing tolerance. Since the order of measurement range of optical sensor is about ten micrometers, the slipping problem causes large measurement error, especially in the case of vibrational or high speed plant. This problem does not occur in the proposed design due to the one body structure. The proposed sensor has advantage of low cost, light weight, and small size. And it is easy to design and manufacture. Simulation works that analysis of stress and strain are performed accurately. To demonstrate the performance of proposed sensor, experiments were implemented to compare with a commercial force/torque sensor (ATI Mini45).

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.94-98
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• 2012

In order to serve the exact torque clamping force, the torque measurement system use the curve fitting algorithm by the least square. The corrected least square curve fitting algorithm which suggested in this paper can surpport more exact clamping force for fastner in variable industry field using the torque. At first, This paper introduces mathematical modeling for curve fitting algorithm, and simulate it. As a result, the corrected least square algorithm have shown lower standard error value than that of the used algoritm with torque, and so this corrected least square algorithm prove high accuracy than nomal least square algorithm. The suggested algorithm will contribute to improvement of cost and safety on industry field with bolt clamping force for precision industry parts, electronics parts, aircraft, aerospace, etc.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.79-86
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• 2009

Recently PMSM(Permanent magnet synchronous motor) are used for the various direct drive applications such as index table, telescope system and so on. Because the position/speed control performance of direct drive PMSM is directly affected by the torque ripple, there are lots of studies to reduce the cogging torque in the motor design stage. In order to verify the motor design, the reliable cogging torque measurement system is essentially required. The measured motor must be rotated in the constant speed under 1deg/sec so that the cogging torque profile is measured correctly. In this study, the cogging torque measurement system which uses the direct drive PMSM and the speed controller to rotate the measured motor in 0.1rpm(0.6deg/sec) has been developed. Simulink/xPC target was used for the controller and data acquisition system. Based on PI controller, DOB and AFC have been applied to eliminate the low frequency disturbances and the periodic speed ripple. The experimental results show the good performance of the speed regulation for the reference speed 0.1rpm and the reliable profile of the measured cogging torque by the developed speed controller.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.642-647
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• 2018

Gas compressors are mostly driven by motors. It is important to measure the power of motors to evaluate their power efficiency, because the mechanical loads of gas compressors are always varied. In order to measure the power given to the driving motors, the torque should be measured. Manufacturers of compressors usually use the torque data to calculate the compressors qualities such as power consumption, efficiencies and failures. In general, measurements for the shaft torque of the compressors have been based upon contact types, strain gauges. In the cases of larger compressors, the contact type of strain gauges have several disadvantages such as large size and high cost. In this study, a relatively inexpensive and simple torque sensing technique that is not restricted to shaft diameter is introduced using visualization technique. Particle image velocimetry (PIV) has been adopted to complete non-contact torques measurements for rotating motors. In order to compare the performance of the newly constructed torque measurement technique, torque measurement by a transducer based on MEMS technology has been performed simultaneously during experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1061-1062
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• 2011