• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.861-863
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• 2005

The current-mode circuit technique to design a bi-directional current transceiver for remote control systems and telemetering systems is presented in this paper. The proposed transceiver can transmit and receive the industrial standard current signal 4-20mA at the same time using two wires connection. The realization method is based on a second generation current conveyor (CCII) and a current mirror, which can be implemented using a commercially available device. To demonstrate the performance of the proposed scheme, the transceiver was simulated by the use of the PSPICE analog simulation program. The simulation results verifying the circuit performance are agreed with the expected values. The crosstalk of the proposed transceiver of about .63dB is observed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.877-879
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• 2013

Imaging device such as digital TV is being popular in a modern society based on communication technology. However, because of internal and external cause of system in the process of transmission, storage and acquisition, image is degraded by noise. Therefore, the importance of denoising technology is being increased, and a research for that is being actively made. In this paper, a weighted filter algorithm that considers different pixels of masks and estimated noise variance was proposed. in order to remove AWGN. And, PSNR(peak signal to noise ratio) was used to represent the excellence of proposed algorithm.

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1369-1379
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• 2001

This paper focuses on a development of a sensor system measuring locations of a vehicle to localize a mobile robot while it tracks on the track (location sensor) . Also it focuses on a system configuration identifying the vehicle's orientation and distance from the object while it is stationary at certain station (position sensor) . As for the location sensor it consists of a set of sensors with a combined guiding and counting sensor, and an address-coded sensor to localize the vehicle while moving on the rail. For the position sensor a PSD (Position Sensitive Device) sensor with photo-switches sensor to measure the offset and orientation of the vehicle at each station is introduced. Both sensor systems are integrated with a microprocessor as a data relay to the main computer controlling the vehicle. The location sensor system is developed and its performance for a mobile robot is verified by experiments. The position measuring system is proposed and is robust to the environmental variation. Moreover, the two kinds of sensor systems guarantee a low cost application and high reliability.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.31-39
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• 2016

This paper describes the design of an ankle rehabilitation robot for the force measurement of a severe stroke patient staying in a bed ward. The developed ankle rehabilitation robot was attached to a three-axis force/torque sensor that could detect force Fx, Fz, and torque Tz and measure the ankle rotation force (Fx) exerted on the ankle and the signal force Fz and torque Tz to be used as a safety device. The robot was designed and manufactured for bedridden stroke patients, and the robot program was manufactured to perform the flexibility rehabilitation exercise for ankle bending and to measure the ankle force to judge the degree of rehabilitation. According to the result of the characteristics test of the developed rehabilitation robot, it was safely operated while the ankle-bending flexibility rehabilitation exercise and the emergency situation were performed. Therefore, it is thought that the developed rehabilitation robot can be used for severe stroke patients.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.900-902
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• 2015

In the modern society, according to the advancement in digital image processing technology, edge detection is being utilized in various application sectors such as smart device and medical, etc. In existing edge detection methods, there are Sobel, Prewitt, Roberts and Laplacian, etc, which uses the mask. These previous methods are easy to implement but shows somewhat insufficient results. Therefore, in order to compensate the problems of existing methods, in this paper, an algorithm that detects the edge using the local mask and morphological operation was proposed and the detection performance was compared against the previous methods.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.238-245
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• 2010

Stroke patients can't use their hands because of the paralysis of their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by grasping a spherical object. At present, the object used in hospital is only a spherical object, and can't measure the force of fingers. Therefore, doctors judge the rehabilitating extent by touching and watching at their fingers. So, the spherical object measuring system which can measure the force of their fingers should be developed. In this paper, the finger-force measuring system with a three-axis force sensor which can measure the spherical-object grasping force is developed. The three-axis force sensor is designed and fabricated, and the force measuring device is designed and manufactured using DSP(digital signal processing). Also, the grasping force test of men is performed using the developed finger-force measuring system, it was confirmed that the average force of men was about 120 N.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.96-104
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• 2013

Study of human-robot Interaction gets more and more attention to expand the robot application for tasks difficult by robot alone. Developed countries are preparing for a new market by introducing the concept of 'Co-Robot' model of human-robot Interaction. Our research of direct teaching is a way to instruct robot's trajectory by human's handling of its end device. This method is more intuitive than other existing methods. The benefit of this approach includes easy and fast teaching even by non-professional workers. And it can enhance utilization of robots in small and medium-sized enterprises for small quantity batch production. In this study, we developed the algorithms for creating accurate trajectory from repeated inaccurate direct teaching and GUI for the direct teaching. We also propose the basic framework for direct teaching.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.66-73
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• 2019

In this paper, we design a new automatic workpiece loading system for the loading and unloading of a workpiece for a CNC lathe. Conventional workpiece loading systems are bulky and require a large area when installed around a shelf. Therefore, an automatic loading system with small horizontal and vertical dimensions and a large loading capacity was designed. Structural analysis of the system was then carried out to assess the displacement and safety of the main components. Following this, the automatic loading system was manufactured according to the structural analysis results and conceptual design, and experiments characterizing the performance of the system were conducted. As a result, the automatic loading system was found to operate accurately and safely, meaning it can be used to load and unload workpieces for a CNC lathe.

• Current Optics and Photonics
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• v.6 no.4
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• pp.392-399
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• 2022

Light-measuring devices (LMDs) are frequently used to measure luminance and color coordinates of displays. However, it is very difficult to use a conventional LMD for measuring the optical properties of virtual-reality (VR) devices with a wide field of view (FOV), because of their confined spaces where the entrance pupil of a LMD is located. In this paper, a new LMD that can measure the optical properties of wide-FOV VR devices, without physical conflict with the goggles of the VR device, is proposed. The LMD is designed to fully satisfy the requirements of IEC 63145-20-10, and a pivot-point correction method for the LMD is applied to improve its accuracy. To show the feasibility of the developed LMD and the correction method, seven VR devices with wide FOV are measured with it. From the results, all of them are successfully measured without any physical conflict, and a comparison to their nominal values shows that the FOVs have been properly measured.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.223-230
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• 2013

When a new nuclear fuel is developed, an irradiation test needs to be carried out in the research reactor to analyze the performance of the new nuclear fuel. In order to check the performance of a nuclear fuel during the irradiation test in the test loop of a research reactor, sensors need to be attached in and out of the fuel rod and connect them with instrumentation cables to the measuring device located outside of the reactor pool. In particular, to check the temporary temperature change at the center of a nuclear fuel during the irradiation test, a thermocouple should be instrumented at the center of the fuel rod. Therefore, a hole needs to be made at the center of fuel pellet to put in the thermocouple. However, because the hardness and the density of a sintered $UO_2$ pellet are very high, it is difficult to make a small fine hole on a sintered $UO_2$ pellet using a simple drilling machine even though we use a diamond drill bit made by electro deposition. In this study, an automated drilling machine using a CVD diamond drill has been developed to make a fine hole in a fuel pellet without changing tools or breakage of workpiece. A sintered alumina ($Al_2O_3$) block which has a higher hardness than a sintered $UO_2$ pellet is used as a test specimen. Then, it is verified that a precise hole can be drilled off without breakage of the drill bit in a short time.