• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.346-350
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• 1996

In optical disk drives, one of commonly used pickup actuator is a Sliding and rotary type of pickup actuator which is cheaper than other pickup actuators and has simple assembly. However, it reported that non-linearity due to friction between a shaft and a sleeve had to be considerably analyzed in design and servo system in employing this type of pickup actuator. In this paper, this friction is modeled as a Coulomb's friction and the effect of friction is examined in the simulation. A digital servo system is applied to pickup actuator with friction in order to have good focusing servo. To enhance focusing servo performance using digital servo merit, frist PD-controller is applied to have fast response performance, second lead-lag compensator is applied to have stable focusing performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.741-744
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• 2002

The closed circuit pump is applied to control rotating speed and direction of hydraulic motor in hydrostatic transmission. To development of this pump, first of all the servo control regulator has to be designed. Mechanical-hydraulic type servo control mechanism is excellent to be compared with electronic-hydraulic type servo control valve to reliability and economy. In this paper to development positive and negative variable displacement type servo regulator, the hydro-mechanical servo control mechanism is calculated and designed with force balance of pilot piston and position feedback of servo piston.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1722-1723
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• 2007

This paper describes a simple method to reduce rotation angle error of mobile robot using omni-wheel[3](omni-bot). This method can be applied to not only omni-bot, but also other robot with a large number of servo motor. Robot using many servo motor as omni-bot is complicated for hardware and software, each servo motor has difficulty in synchronizing. Three servo motor, three omni-wheel and three serial servo motor controller is used, PC or Micro Processor interface with the serial servo controller through "SSC100" protocol. In order to check the improvement of the proposed serial servo synchronization compared to existing sequential communication method. comparing object is rotation angle error of omni-bot. The results of this make building of omni-bot system easy and decrease rotation angle error.

• Journal of Welding and Joining
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• v.17 no.4
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• pp.1-5
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• 1999

Servo Gun은 기존의 일반적인 Spot용접Gun에서 가압 및 개방에 사용되는 Air Cylinder를 Servo Motor로 대치한 신개념의 Spot용접Gun으로 여러 가지의 우수한 기능과 특징을 가지고 있어 적 용범위의 확대가 기대되고 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1179-1182
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• 2011

RC servos are electro-mechanical devices that respond to a control signal, which instructs them to move their output shaft to a certain position. A servo is normally plugged into a radio receiver with a three pin connector. The three wires are a power (usually 4.8V to 6.0V), a ground, and a signal wire. The signal wire carries a PWM (Pulse-Width Modulation) signal consisting of a 1-2msec pulse repeated 50 times a second. A 1.5msec pulse will tell the servo to move to its output shaft to the center position, 0 degrees. For a servo with a 180 degree of motion, a 1msec pulse will move the servo to -90 degrees, and a 2msec pulse will move the servo to +90 degrees. In order to development a humanoid robot, mechanical design, fixtures design, analysis of kinematics, implementation moving program, selection of RC servo motor and controller are required. This study was performed to experimentally compare the rotation range of RC servo motors according to change of a periods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1685-1691
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• 2004

The objective of this study is aimed at reducing the contour error of AC Servo derives by improving the interpolation error of each axis through variable structure control system. The errors in machining process by AC Servo motor are due to many elements, such as the delay of the servo drivers, friction and the gain mismatch between x axis and y axis motors and so on. Sliding mode control system is applied to a AC servo drive as a numerical example in this paper. The experiment results which are compared with those of typical PI scheme show the validity of improvement in circular interpolation error of the system.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.129-130
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• 2007

Self servo track writing(SSTW)은 servo track writer(STW)를 이용하지 않고 hard disk drive의 내부 VCM을 이용하여 servo track을 기록하는 방식이다. SSTW는 이전 servo track을 상대적인 reference로 하여 기록하게 되므로 초기에 발생된 error와 외부의 disturbance의 영향으로 error는 급속하게 증가된다. 이것을 radial error propagation 이라 한다. 본 논문에서는 radial error propagation을 억제하기 위한 correction signal을 설계하고 servo writing 과정에서 발생하는 disturbance의 영향을 제거하기 위하여 disturbance observer(DOB)를 add-on type으로 구성하여 tracking 제어기를 설계하였다. 또한 DOB를 적용한 경우와 유사한 gain margin, phase margin과 sensitivity function을 갖는 제어기를 설계하여 그 성능을 비교하였다. 제안된 방식은 radial error propagation을 억제 하였을 뿐만 아니라 disturbance의 최소화하여 쓰여진 track의 DC track spacing과 AC track Squeeze가 개선된 것을 모의실험을 통하여 검증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1146-1151
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• 2003

Pneumatic servo valve is an electro-mechanical device which change electric signals to a proper pneumatic signals, that is, flowrate and pressure. In this study, a pneumatic servo valve was designed and each simulation was conducted on any variation in the flowrate depending upon the magnetic force of the linear force motor and the displacement of the spool. And permanent magnet was used as a material for the plunger of the servo valve. Thereby, a low electrical power consumption type coil was desinged. And a modeling for the coil design was conducted by using the magnetic circuit. also, the feasibility of the modeling was verified by using a commercial magnetic field analysis program. The designed and fabrication of the spool and sleeve, position sensor, servo controller and the dynamic characteristic verified by the experiment.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.693-700
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• 1999

The Servo motor is consistent with the magnet rotor, winding, magnetic back iron and the sensor. Especially the soft magnetic back iron in the servo motor, which consists of the magnet rotor and winding, and between these two components lies the magnetic circle. Its important to monitor the output power of to make conclusive decision for designs. In these days main household electrical appliances, business machinery and tools are made by process of miniaturization. Because of this miniaturization in hardware, miniaturization of the servo motor is essential But the decrease inside affects the power output. For improve of these has been several attempt at improving the power output of these smaller servo motors. There has been experiment in the servo motor composition, composing of the improvement of the soft magnetic back iron through comparison of the out put power plans are being made.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1428-1432
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• 2007

The object of this paper is development of pneumatic servo actuator technique for energy saving type. In this paper, consist of pneumatic servo actuator technique is pneumatic servo valve, pneumatic motor and cylinder. This technique applied a automobile, aerospace engineering, a ship, defence industry and industrial machine because it have high response, high speed, high precision control, low friction etc., compare with previously technique. But it depend on import the whole quantity. So this study, suggest that through the development of servo actuator applicable the use of industrial field.