• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.67-72
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• 2001

In this study, a methodology of synchronous control which can be applied to position synchronization of a two-axes driving system has been developed. The synchronous error is caused by model uncertainties and torque disturbance of each axis. To overcome these problems, the proposed synchronous control system has been composed of two speed controllers, disturbance observers, and one synchronous controller. The speed controllers, based on the PID control law are aimed at the following to speed reference. And the parameters of speed controllers have been designed in order for the speed response fo the second axis to correspond with the one of the first axis. The disturbance observer has been designed to restrain the torque disturbance. The synchronous controller eliminates the synchronous error by controlling the speed of the second axis. The effectiveness of the proposed method has been verified through simulation.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.789-796
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• 2016

The weight of an antenna system pointing satellite on the mobile platform is restricted by the weight limit of the mobile platform. The maximum power of the actuator driving the antenna system is thus limited because a high power actuator needs a heavier weight. Thus, a drive system is designed to have a low torque requirement by reducing the gravitational torque depending on gravity or acceleration of the mobile platform, including vibration, shock, and accelerated motion. To reduce the gravitational torque, the mathematical model of the gravitational torque is preferentially obtained. However, the method to directly estimate the mathematical model in an antenna system has not previously been reported. In this paper, a method is proposed to estimate the gravitational torque as a mathematical model in the antenna system. Additionally, a method is also proposed to calculate the optimal weight of the balancing weight to compensate for the gravitational torque.

• Journal of Mechanical Science and Technology
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• v.19 no.12
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• pp.2205-2212
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• 2005

In this paper, the cutting torque of a CNC machine tool during machining is monitored through the internet. To estimate the cutting torque precisely, the spindle driving system is divided into two parts: electrical induction motor part and mechanical part. A magnetized current is calculated from the measured three-phase stator currents and used for the total torque estimation generated by a spindle motor. Slip angular velocity is calculated from the magnetized current directly, which gets rid of the necessity of a spindle speed sensor. Since the frictional torque changes according to the cutting torque and the spindle rotational speed, an experiment is adopted to obtain the frictional torque as a function of the cutting torque and the spindle rotation speed. Then the cutting torque can be calculated by solving a $2^{nd}$ order difference equation at a given cutting condition. A graphical programming method is used to implement the torque monitoring system developed in this study to the computer and at the same time monitor the torque of the spindle motor in real time through the internet. The cutting torque of the CNC lathe is estimated well within an about $3\%$ error range in average in various cutting conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.512-519
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• 2016

In this study, the tire road friction estimation(TRFE) algorithm for controlling the rear wheel driving force of a 4WD vehicle during acceleration is developed using a standard sensor in an ordinary 4WD passenger car and a speed sensor. The algorithm is constructed for the wheel shaft torque, longitudinal tire force, vertical tire force and maximum tire road friction estimation. The estimation results of shaft torque and tire force were validated using a torque sensor and wheel force transducer. In the algorithm, the current road friction is defined as the proportion calculated between longitudinal and vertical tire force. Slip slop methods using current road friction and slip ratio are applied to estimate the road friction coefficient. Based on this study's results, the traction performance, fuel consumption and drive shaft strength performance of a 4WD vehicle are improved by applying the tire road friction estimation algorithm.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.60-65
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• 2022

This study focuses on the driving control design of an index, which is a key component of a rotary transfer machine that is effective in improving productivity and reducing manufacturing costs by shortening cycle time. Although various index studies have been conducted on the rotation of workpieces such as general-purpose machine tools and tilting indices, the development of an index for rotary transfer machines for transfer is insufficient. The index consists of a body, table, hydraulic cylinder, motor, reducer, and curved coupling. The torque of the table for driving was selected, and the angular velocity and torque pattern were simulated using the motor manufacturer's program. The specifications of the drive motor were determined based on the selected torque.

• 연구논문집
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• s.33
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• pp.53-65
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• 2003

Electrostatic micro-motors can be divided into three classes: (i) salient type side drive motor, (ii) radial gap type wobble motor, (iii) axial gap type wobble motor. The working mechanism, torque evaluation, fabrication, and operational characteristics of each micro motors are compared. It is proved that axial gap type wobble motor has the bigger generating torque than that of the other type. The gear ratio of wobble motors increases the driving torque at the cost of a decreasing angular speed and decreases the friction because of the rolling motion instead of sliding at the bearing. Techniques for characterizing micro-motors performance are presented.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.99-105
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• 2004

Internet provides the useful method to monitor the current states of the machine tool no matter where a personnel monitors it. In this paper, a monitoring method of the torque of the machine tool's spindle induction motor using interne is suggested. To estimate the torque accurately, spindle driving system of an CNC lathe is divide into two parts, induction motor part and mechanical part attached to the induction motor spindle. Magnetizing current is calculated from the measured 3 phase currents without speed sensor used to estimate the torque generated by an induction motor. In mechanical part of the system, some of the torque is used to overcome friction and remaining torque is used to overcome cutting force. An equation to estimate friction torque is drawn as a function of cutting torque and rotation speed. Graphical programming is used to implement the suggested algorithm. to monitor the torque of an induction motor in real time and to make the estimated torque monitored on client computers. Torque of the spindle induction motor is well monitored on the client computers in about 3% error range under various cutting conditions.

• Ocean and Polar Research
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• v.26 no.2
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• pp.333-339
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• 2004

This paper is concerned with an experimental investigation about tractive performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of $0.9\;m(L)\;{\times}\;0.75\;m(B)\;{\times}\;0.4\;m(H)$ and the weight of 167 kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of $6.0\;m(L)\;{\times}\;3.7\;m(B)\;{\times}\;0.7\;m(H)$. Slip of vehicle and driving torque of motor were measured with respect to experimental variables; grouser span, grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. $L_8$ orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables on traction performance are evaluated.

• Fibers and Polymers
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• v.4 no.4
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• pp.161-168
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• 2003

An investigation of the dimensionless torque in the newly developed cone drum twister texturing mechanism is reported. The cone drum twister is one of the outer surface contacting friction-twisting devices in false-twist texturing. In this cone drum twister, a filament yam passes over the surface of the cone drum that rotates by the passing yarn without a special driving device. This research is composed of the theoretical analysis of the false twisting mechanism and the experimental analysis at room temperature. The equations have been derived which shows interrelationship of the conical angle of cone drum, the wrapping angle, the drag angle, and the yam helix angle. Theoretical values of dimensionless torque were calculated and were compared with the experimental results. It is shown that, as the conical angle and the projected wrapping angle increased, the dimensionless torque also increased. But the conical angle was reached to ${30.75}^{\circ}C$, the dimensionless torque decreased.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1030-1032
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• 2003

Single phase SRM(switched reluctance motor) can not be start by itself because positive torque is generated in limited section. Therefore single phase SRM need starting device which is place the rotor in positive torque section when motor is begun to start. The prototype of salient pole rotor type single phase SRM, fabricated in previous research, has permanent magnet starting device. It is installed in bottom of the rotor for starting by itself. But, it is affected the motor when driving and cause the decrease of torque and speed. On this paper, average torque of the prototype was measured according to installation of the starting device or not. And influence of the staring device on average torque was confirmed by comparison of the results.