• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.98-101
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• 2001

Linear motor feature a direct connection to the machine tool, therefore a direct route for heat transfer. The heat dissipation of linear motor machine is affected by the maximum temperature rise of the primary part, coil and the cooling method. To minimize temperature induced dimension changes and decrements of performance, linear motor machine require effective cooling mechanism. To evaluate cooling performance of existing linear motor machine, some experiments about temperature profile are performed using thermocouple recorder. Due to the lack of information about internal structure, only some finite element modeling is prepared and analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.993-996
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• 2000

A brushless linear motor is suitable for a high-accuracy servo mechanism. It is also suitable for operation with higher speed and precision. Since it does not involve some sort of mechanical coupling, linear driving force can be applied directly. Basic models including magetomotive force and electromotive forces are introduced and simplified. Both conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Several system operational characteristics have been observed. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.472-475
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• 1997

It is well known that pneumatic motors convert fluid power into mechanical power with a low efficiency. The Value of the efficiency depends on several factors, of which the most important are ; type of motor, speed, supply pressure, sie and geometry of the motor. This paper presents an analytical and experimental study of the performance of he vane type pneumatic motors. This investigation deals with all the pneumatic motors. This investigation deals with all the pneumatic motors. This investigation deals with all the major aspects of the air flow through a vane type pneumatic motor and pints out which are the main causes of the low efficiency of the motor, and therefore indicates which changes in a motor design an lead to optimum performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.145-148
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• 2003

Thermal characteristics according to the bearing preload arc studied for the four type spindles with high frequency motor. For the analysis. three dimensional models are built considering heat transfer characteristics such as natural and forced convection coefficients, Bearing and motor are main heat generation, and heat generation by ball bearings as a function of load. viscosity and gyroscopic moment effect are considered. Unsteady-state temperature distributions and thermal displacements according to the bearing preload are analyzed by using the finite clement method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.942-945
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• 2003

Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of motor. Until now, measuring method has been used to measure vibration by the accelerometer, this method has been not measured for the vibration in some parts of brush and commutator because of motor construction. This research was purposed on the accurate analysis. using laser vibration analyzer, of noise cause against the difficult part in old times. By using this measured data, we would like to use for the design of silent motor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.466-471
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• 2003

In order to analyze linear motor driven feed system, preliminary studies have been conducted focusing on the performance evaluation of the system based on the various combination of control gain along with acceleration. Tentative simulation revealed that due to the complexity of control system reduced number of control condition is recommended. Actual machining process with conventional feed system using endmill tool was employed as a preliminary study. Several sensing methods including AE, acceleration sensors and tool dynamometer were used. Results revealed the consistency in AE and cutting resistance. There were inconsistent empirical results in accelerometer probably due to the insensitivity of the sensor signal with respect to the experimental system

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.70-76
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• 2007

The purpose of this study is to analyze the characteristics of a domestic developed hydraulic axial piston motor. An experimental apparatus was constructed and the output torque, the input oil pressure, the input flow rate, the speed of motor and oil temperature were measured. They were measured under both no load and load conditions. The results are as follows; 1. Motion of motor became steady state conditions after 5 seconds. 2. Output torque of motor was proportional to input oil pressure under both load and unload. 3. Speed of motor decreased with increasing load. 4. Oil temperature was almost constant. The results of this study will offer the basic data in designing and operating hydraulic axial piston motors.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1391-1396
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• 2009

The direct drive motor used in a precision motion rotate at about 1/10 speed and high torque comparing with general rotary motor. Excessive heating of the coils cause an exacerbating the heat problems and reducing the performance of motor. Because the rotation speed of the rotor and surrounding air is low, the motor can not be inefficiently cooled, the thermal analysis in the motor is very important. As the variations of rotation speed and torque, the temperature of several parts is measured and the features of the heat transfer is analyzed and improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.420-424
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• 2012

A 2-axis gimbal system is one of main disturbance sources affecting on image jitter response of a satellite. The gimbal system can be rotated on its azimuth and elevation axes, resulting in variation of its moment of inertia and structural modes, so that generates non-linear vibration characteristics. In order to estimate the jitter response, it is an indispensable process to characterize micro-vibration disturbance of the 2-axis gimbal system. In the present research, the vibration characteristics of the 2-axis gimbal system was investigated with respect to the types of stepping motors. The micro-vibration tests were performed for 2-phase and 5-phase stepping motors. The test results show that the disturbance can be reduced with vibration attenuation ratio of 60% by replacing the 2-phase stepping motor with the 5-phase one.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.977-981
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• 2000

Direct drive linear motors have large potential for use as high speed machine tool feed units since they can increase machining rates and improve servo accuracy by eliminating gear related machining problems. So, in this paper, characteristic of 2-axis linear motor feed unit are studied and control gain are adjusted considering positioning, velocity, acceleration and static stiffness. We confirm linear motor feed unit are affected value of control gain sensitively, because drive directly. From the experiment, this feed unit has l${\mu}{\textrm}{m}$ micro step resolution, 5.7${\mu}{\textrm}{m}$ positioning accuracy and under 60${\mu}{\textrm}{m}$ circularity.