• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.3-7
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• 2003

Usually, the thrust is calculated by magnetic equivalent circuit modelling method for thrust capacity and accuracy progress of position control about a Linear Pulse Motor of which position precision is good and open-loop control is possible within Linear Motors. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force Method. For calculating accuracy thrust by using these every method, the thrust is calculated and compared by Lorentz Force Method, Magnetic Coenergy Method, and Maxwell correspondence force Method. And that becomes important factor at the comparison of each capacity and parameter of Motor. So this study wants to compare and analyze measurement data and calculating data of the static force of Linear Pulse Motor. and then we can get more accuracy method, calculating the static thrust of Linear Pulse Motor(LPM).

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.3
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• pp.13-19
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• 2010

Hydraulic systems are widely used as a power transfer and/or power control system due to its flexibility, controllability, accuracy and high power density. Valve controlled and/or pump capacity controlled systems are normally adopted as a control device, but nowadays pump speed controlled systems are emerging as a new energy-efficient hydraulic control system. In this paper the pump speed controlled system for the cylinder position control of a counter balance circuit is investigated by simulation study and position control experiments were carried out. As a result, the possibility and efficiency of the pump speed controlled system were verified.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.530-536
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• 2004

In this paper a servo-system is developed to improve straightness of linear motor stages. When a linear motor stage is used for high-precision linear motion systems, high precision straightness accuracy is necessary to meet the required position accuracy. In such cases, machining and assembling cost increases to improve the straightness accuracy. An electro-magnetic actuator which is relatively cost effective than any other conventional servo-systems is suggested to compensate the fixed straightness error. To overcome the compensation error due to the friction, a sliding mode control is applied. The effectiveness of the suggested mechanism and the control performance are illustrated along with some experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.359-362
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• 2003

The aerostatic stage. which is used in semiconductor process, is demanded higher velocity and more precise accuracy for higher productivity and integrated performance. So, in the case of XY stage, H type structure, which is designed two co-linear axis of guide-way, driving force in one surface, has advantage of velocity and accuracy compared to conventional tacked type XY stage. To analyze characteristics of H type aerostatic stage, H type aerostatic surface XY stage is made, which is driven by linear motor and detected position with precise optical linear scale. And, analyze characteristics of motion error, effect of angular motion on positioning accuracy error and effect of simultaneous control on variation of velocity.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.1
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• pp.17-26
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• 2017

Latency occurs in RTK, where the measured position actually outputs past position when compared to the measured time. This latency has an adverse effect on the navigation accuracy. In the present study, a system that estimates the latency of RTK and compensates the position error induced by the latency was implemented. To estimate the latency, the speed obtained from an odometer and the speed calculated from the position change of RTK were used. The latency was estimated with a modified correlator where the speed from odometer is shifted by a sample until to find best fit with speed from RTK. To compensate the position error induced by the latency, the current position was calculated from the speed and heading of RTK. To evaluate the performance of the implemented method, the data obtained from an actual vehicle was applied to the implemented system. The results of the experiment showed that the latency could be estimated with an error of less than 12 ms. The minimum data acquisition time for the stable estimation of the latency was up to 55 seconds. In addition, when the position was compensated based on the estimated latency, the position error decreased by at least 53.6% compared with that before the compensation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.1-7
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• 2005

This paper deals with the position control for a feed drive system in CNC milling machine. The study shows that reduction in tacking error does not necessarily increase contouring accuracy, and proposes that a proper control scheme is able to exhibit the optimal tracking and contouring accuracy. The proposed scheme is to fix the parameter of the contouring control, and to find the optimal value of the parameter of the tracking control, which is automatically tuned. The effectiveness of the proposed scheme is confirmed through simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.166-173
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• 2012

Plug-in Hybrid Electric Vehicle is driven by the engine, the primary traction motor, and the secondary auxiliary motor generating the electric power for battery charging. Secondary auxiliary motor should be connected to the engine or separated from the engine by the clutch system. This paper presents the position controller of the BLDC motor for the clutch system of Plug-in Hybrid Electric Vehicle. The BLDC motor can be applied to the clutch system in spite of it's low accuracy of the position control due to high gear ratio between the clutch and the motor. Since the attachment and the detachment between the motor and the engine should be carried out within 0.3 seconds, the position controller with fast acceleration and deceleration is implemented. For the torque control with braking operation for the BLDC motor, the modified bipolar PWM method with low current ripple compared to the conventional unipolar PWM is presented. The position control performance of the BLDC motor for the clutch system is verified through the simulation and experiments.

• Journal of Magnetics
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• v.19 no.1
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• pp.90-100
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• 2014

Position estimation that uses only active phase voltage and current is presented, to perform high accuracy position sensorless control of a SRM drive. By extracting the amplitude of the first switching harmonic terms of phase voltage and current for a PWM period through Fast Fourier Transform (FFT), the flux-linkage and position are estimated without external hardware circuitry, such as a modulator and demodulator, which result in increased cost, as well as large position estimation error, produced when the motional back EMF is ignored near zero speed. A two-phase SRM drive system, consisting of an asymmetrical converter and a conventional closed-loop PI current controller, is utilized to validate the performance of the proposed position estimation scheme in comprehensive operating conditions. It is shown that the estimated values very closely track the actual values, in dynamic simulations and experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.571-576
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• 2015

This paper proposes an auto-parking controller for omnidirectional mobile robots. The controller uses the multi-sensor system including ultrasonic sensor and camera. The several ultrasonic sensors of robot detect the distance between robot and each wall of the parking lot. The camera detects the global position of robot by capturing the image of artificial landmarks. To improve the accuracy of position estimation, we applied the extended Kalman filter with adaptive fuzzy controller. Also we developed the fuzzy control system to reduce the settling time of parking. The experimental results are presented to verify the usefulness of the proposed controller.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.504-509
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• 1993

A heavy load driving system for the gun laying control is designed with the analysis of performance in pointing accuracy and speed. To eliminate the firing noise and high frequency system noise, a .PI. filter is implemented in conjunction with the PI velocity control. To incorporate the gunner's commands in the PID position control loop easily, a .mu.-processor is utilized in the position control loop. Main difficulties in the heavy load driving system exist in the design of motor drivers and heat sinkers. With an appropriate design of the motor drivers and heat sinkers, the performance of the gun laying system is analyzed by the simulation.