• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.789-797
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• 2006

A new method for the GPS repeater based indoor positioning is proposed and its feasibility is verified by experiments in previous paper. But the problems how can identify switching GPS repeater's ID and when switching will be occurred are remained. To solve the problem faced with, we propose the time synchronized switching GPS repeater and the methods of the detection of switching time and the estimation of TDOA. First, switching GPS repeater retransmits the signals synchronized on GPS time, sequentially. Always, first switching time is synchronized with 1 PPS. Second, we formulate the detection of switching time and the estimation of TDOA and propose the various methods. No method is existed absolutely superior to others in any conditions but the method is existed superior to others in specific condition. Finally, feasibility of indoor positioning using time-synchronized switching GPS repeater is evaluated through experiments in anechoic chamber and general environment with multipath.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.952-959
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• 2016

This paper proposes a novel indoor positioning system (IPS) that uses a calibrated camera sensor network and dense 3D map information. The proposed IPS information is obtained by generating a bird's-eye image from multiple camera images; thus, our proposed IPS can provide accurate position information when objects (e.g., the mobile robot or pedestrians) are detected from multiple camera views. We evaluate the proposed IPS in a real environment with moving objects in a wireless camera sensor network. The results demonstrate that the proposed IPS can provide accurate position information for moving objects. This can improve the localization performance for mobile robot operation.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.220-225
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• 1998

In GPS (Global Positioning System) positioning, various measures can be used to select satellites or to evaluate the positioning results. Among these, GDOP (Geometric Dilution of Precision) and RGDOP (Relative GDOP) are the most frequently used. Although these measures are frequently used, the relationship between them is not clearly known. Moreover, the condition number is used as a traditional measure of numerical stability in solving linear equations. Sometimes, the volume of a tetrahedon made by the line of sight vector is used for simplicity. All of these measures share some common properties as well as differences. The relationships between these measures are analyzed in this paper.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.9-13
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• 2007

We describe how to control a piezoelectric actuator using the open-loop method for point-to-point positioning. Since piezoelectric actuators have nonlinear characteristics due to hysteresis and creep between the input voltage and the resulting displacement, a special method is required to eliminate this nonlinearity for an open-loop drive. We have introduced open-loop driving methods for piezoelectric actuators in the past, which required a large input voltage and an initializing motion sequence to reset the state of the actuator before each movement. In this paper, we propose a new driving method that uses the initializing state. This method also utilizes the overshoot from both the upward and downward stepwise drives. Applying this method., we obtained precise point-to-point positioning without the influence of hysteresis and creep.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.129-132
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• 1996

There is a tendency nowadays to produce increasingly miniaturized electronic equipment which incorporate parts that have to be precisely positioned, like lenses, heads and CCD's in scanners, printers, copiers, VCR's, optical fiber modules, etc. In contrast to the production process of precision parts, which is currently being carried out automatically, the assemblage process is still being performed by specially skilled technicians. The assemblage process comprises normally the following steps: firstly, the parts are roughly positioned and partially fixed, secondly, the parts are manually nudged towards the target position and finally glued, screwed or welded. This paper presents a system that uses six piezo Impact Drive Mechanisms for accurate micro positioning within three degrees of freedom (lateral and longitudinal translation and rotation). The system is designed to positioning a printed circuit board with an accuracy better than 3 .mu.m (for translations), 5 mrad (for rotation).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.255-256
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• 2009

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.49-53
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• 2007

In this study, we investigated experimentally the potential of a planer positioning mechanism with three degrees of freedom using a flexure guide and an electromagnetic linear motor. The goal was to produce a multi-axis positioning system with nanometric resolution over a 1-mm stroke. An $X-Y-\theta$ stage was designed based on previous results from a single-axis prototype and was constructed with a flexure guide mechanism and voice coil motor type linear actuators. We examined the necessity of a driving method and control system to ensure high resolution for multi-axis positioning. Experiments were conducted to evaluate the performance, and the results confirmed the mechanism's potential; fine point-to-point (PTP) positioning was achieved over a 1-mm stroke, with a resolution of 2 nm for translation in X-Y and 0.01 asec for yaw in $\theta$.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.362-365
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• 1990

This paper proposes the precise positioning controller. The pricision of this controller is improved by considering stiction, coulomb friction and biscous friction. These frictions have nonlinearities both typical and mechanical. According to the result in this paper, good precision is abstained by adding a simple friction compensator to a PI controller.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.79-90
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• 1993

A design method of DPS control algorithm for adpting rotable thruster is introduced by applying servo system design method and the control algorithm is evaluated on the basis of the results of computer simulations performed for a semi-submersible 2-lower hull 8-column type platform. It is observed from the simulation results that position error due to the irregular drifting forces becomes zero after very short regulating time and dynamic positioning system is robust in spite of random disturbance.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.200-205
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• 1989

The performance of conventional robot arms is inhibited by trade-off between speed and accuracy. Because these systems measure only joint angles, in spite of slow speed, they must rely on a stiff structure in order to attain positioning accuracy. Lightweight links would allow faster motion, but their flexibility would also produce positioning errors. This research is involved with the development and evaluation of an End-point Control System whose major goal is to compensate for link deflections and thus mitigate the speed versus accuracy conflict in conventional manipulator.