• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.19-26
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• 2004

정밀 공작기계에 있어 안내/이송계(이하, 이송시스템)의 중요성은 새삼스럽게 강조할 필요가 없을 정도로 꾸준히 강조되어 왔다. 또한, 최근 들어서는 광부품, 반도체, 디스플레이 등 초정밀 가공기술시장의 급격한 확대에 따라 이들 산업의 제조장비용 핵심기술로서 이송시스템의 역할 및 수요는 훨씬 확대되어가고 있으며, 오히려 요구정밀도 면에서는 공작기계상에서의 요구성능을 초월하여, 이들 산업에서 개발된 기술이 역으로 공작기계에 적용되어야하는 시점으로까지 진전되고 있다.(중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.162-162
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• 2004

위치결정 기술은 초정밀 미세 기술의 발달과 제품의 소형화, 경량화에 대한 요구가 늘어나면서 고정밀화가 가속화되어 현재는 나노미터 수준의 위치정밀도를 요구하고 있다 현재 널리 사용되어지는 표면형상 측정기인 AFM은 분해능과 정밀도는 우수하지만, 이송 스테이지의 제한으로 측정영역이 좁은 단점이 있다. 이를 극복하기 위해서 이중서보를 사용한 방식들이 많이 제안되어 왔고 단일 서보를 사용하는 방식들도 연구되고 있다. 하지만 이중서보 방식은 여러 가지 액츄에이터와 컨트롤러를 사용해야하므로 제어알고리즘과 시스템이 복잡해지는 단점을 가지고 있다.(중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.458-461
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• 1995

A new type of rotational motor which is developed has a resolution smaller than 10 $^{-4}$ radian and can be accessed for full rotational angles. The operation principle of the motor is based on inchworm motion of two belt driving mechanism. Flexure hinge mechanism, which is pertinent to symmetry construction of the motor, is designed to minimze the effort to frame and is analyzed by using finite element method. Depending on input signal amplitude, rotational angle by one cycle is varied form 0.2*10 $^{-4}$ rad to 9.76* $^{-4}$ rad. This shows that it has the capability of getting very small rotational angle by considering radius of rotor and amplitude of input signal.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1041-1044
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• 2002

Inchworm linear motor is one of the ultra precision position apparatuses and has many kinds of forms and structures according to the conditions of working space and range. In this paper, the Inchworm linear motor consists of three PZTs(Piezo-electric transducer), three columns ma two plates. finite element method was used to determine the type or hinges installed in column of inchworm linear motor DOE(Design of experiment) was used to determine the optimal design condition of a column by comparing the von-mises stresses according to the change of thickness of hinge, round of hinge, height of arm, angle of v-notch, round of v-notch and thickness of column. From the result, round of hinge, height of arm and thickness of hinge were determined a effective design parameters.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.126-133
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• 2008

Linear motors are efficient mechanism that offers high speed and positioning accuracy. By eliminating mechanical transmission mechanisms such as ball screw or rack-pinion, much higher speed and greater acceleration can be achieved without backlash or excessive friction. However, an important disadvantage of linear motor system is its high power loss and heating up of motor and neighboring machine components on operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. This paper presents an investigation into the thermal behavior of linear motors with the objective of deriving the optimum cooling conditions. To reach these goals several experiments were carried out, varying operating and cooling conditions. From the experimental results, this research proposed cooling conditions to improve the thermal characteristics of the linear motors.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.76-82
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• 2005

In this paper, the pole placement controller based on the Robust Internal-loop Compensator (RIC) structure, which has inherent structural equivalence to disturbance observer, is proposed to control a linear positioning system. This controller has the advantage to easily select controller gains by using pole placement without loss of that of original RIC structure. The principal is to construct the pole placement controller for a nominal internal model instead of unknown real plant. Using linear motion experiment showed the effectiveness of the proposed controller.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.154-163
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• 1999

In this paper, an ultra precision positioning system has been developed using dual servo loop control. For positioning system having long distance with ultra precision , the combination of global stage and micro stage was required. A servo motor based ball screw is used as a global stage and the piezo actuator as a micro stage. For the improvement of positional precision, the digital Chebyshev filter is implemented in the developed to dual servo system. Therefore, the positional repeatability has been achieved within ${\pm}$ 10 mm, and this technique can be applied to develop precision semiconductor equipments such as lithography steppers and probers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.375-378
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• 2005

Voice Coil Motor is used linear motion actuator system that require precision positioning control. In order to control precision positioning of voice coil motor, Mathematical model of voice coil motor is needed. Mathematical model is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. The induced model can predict output displacement according to duty ratio and amplitude. The model is verified by experimental test. Simulated results have tracking errors of less than 10 percent of experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.15-27
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• 1997

Quasti-static cutting force variations in milling process are measured indirectly using spindle motor current. Quasi-static sensitivity of the spindle motor current is higher than that of the feed motor current. Magnitude of the spindle motor current is independent of cutting direction. The linear relationship between the cutting force and the spimdle motor RMS current at various spindle rotational speed is obtained. Frequency/ Voltage(F/V) converter voltage is measured to identify the spindle speed and to determine the cutting force at various spindle speeds. Overload on the tool during milling process can be detected using the proposed indirect cutting force measurement. Based on these measurements, cutting force is regulated at a constant level by feedrate control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.294-301
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• 2016

Recently, the solar tracker has been used to improve the efficiency of solar energy. Solar tracking technologies are classified into the sensor-based method, the program-based method, and the hybrid method. Solar trackers using an AC motor and CdS sensor are low in cost, but the precision of the positions is low, owing to the inertia of the motor and the scattering of sunlight. To compensate for the low precision, we implement a CdS sensor module and propose an AC motor control method using error value. To evaluate the performance of the solar tracker, we implemented a solar water heater. From the experimental results, the solar tracker can achieve ${\pm}2mm$ accuracy for sun, can satisfy ${\pm}15mm$ as a limited error value, and provides a 32% performance enhancement in KSB8202 criteria.