• 한국기계연구소 소보
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• s.18
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• pp.67-74
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• 1988

The force sensor is essentially required in controlling robot manipulator in such applications as precise assembly of mechanical parts, deburring and polishing and various kinds of 6-axis force sensors are developed for these application. This paper presents the algorithm of horizontal assembly of circular cross-sectional workpiece using 3-axis force sensor and procedure to develop the sensor. The sensor is calibrated and tested using AID converter and 16 bit micro computer. The result is $\pm$0.03% FS of zero stability, 0.1%FS of linearity and $\pm$0.05% FS of resolution. The sensor will be used in the research of robot application such as assembly and deburring interfaced with micro computer based robot controller which is under development at the robotics lab.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.1
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• pp.141-150
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• 2013

This study proposes technology using Active Shape Model to track the object separating it by depth-sensors. Unlike the common visual camera, the depth-sensor is not affected by the intensity of illumination, and therefore a more robust object can be extracted. The proposed algorithm removes the horizontal component from the information of the initial depth map and separates the object using the vertical component. In addition, it is also a more efficient morphology, and labeling to perform image correction and object extraction. By applying Active Shape Model to the information of an extracted object, it can track the object more robustly. Active Shape Model has a robust feature-to-object occlusion phenomenon. In comparison to visual camera-based object tracking algorithms, the proposed technology, using the existing depth of the sensor, is more efficient and robust at object tracking. Experimental results, show that the proposed ASM-based algorithm using depth sensor can robustly track objects in real-time.

• Journal of Biosystems Engineering
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• v.41 no.2
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• pp.67-74
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• 2016

Purpose: Many tractors have adopted the horizontal control system designed to maintain the three-point mounted implements in horizontal position when they are tilted sideways. The control system rotates the implement in the opposite direction to the inclination of rear axle of the tractor. However, the current control system was found to have poor performance in accuracy and response. A new control system was therefore developed to improve the performance. Methods: The new control system was designed to get the response of the implement to be started earlier by using the tilt information from the front axle of the tractor. By this approach, the rotation of the implement can be adjusted as required to make it horizontal at the expected time, even though the response is slow. The optimal values of the control parameters for the new system were determined by computer simulation and validated by a performance test conducted with an obstacle of 120 mm height on a flat concrete surface. The performance of the control system was evaluated by the root mean square error (RMSE) of the rotation angle of the implement with respect to the actual inclination of the rear axle. Results: The new control system reduced the RMSE of the current control system by 44.6% indicating a high performance improvement. The inclination of the front axle was easily obtained from a sensor mounted on the front axle of the tractor and used as input to the new control system. Conclusions: The method of getting the response of the implement to be started earlier by utilizing the inclination information of the front axle can be applied to improve the performance of the current control system at least cost.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.139-141
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• 1996

Among various welding parameters, the welding current which is inversely proportional to the tip-to-workpiece distance in GMAW is an essential parameter to monitor the GMAW process of horizontal fillet joints. For the case of weld defect such as overlap in horizontal fillet welding, therefore, the signal processing for process monitoring or automatic seam tracking should be modified by considering the weld pool surface geometry including the corresponding weld defect. In other words, the adequate signal processing algorithm is indispensible to improve the performance of the arc sensor. However, arc sensor algorithm already developed usually focus on weld seam tracing but do not considering the weld qualities. In this paper, various experiments were carried out to investigate the tendencies of the weld defects when weaving motion is added, and the experimental method based on 2$^n$ factorial design was proposed for deriving the mathematical model between the leg length and the various welding conditions. Moreover, a signal processing method based on the artificial neural network(Adaptive Resonance Theory) was proposed far discriminating the current signal of sound weld beads from that of weld beads with overlap. Finally, the algorithm for weld seam tracking combined with the mathematical modeling and the signal processing method was carried out to track the weld line in conjunction with the improvement of the weld qualities. The reliability of the proposed algorithms were evaluated through various experiments, which showed that the proposed algorithms could be effectively used for arc welding automation.

• Journal of Welding and Joining
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• v.16 no.3
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• pp.102-110
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• 1998

The horizontal fillet welding is prevalently used in heavy and ship building industries to fabricate the large scale structures. A deep understanding of the horizontal fillet welding process is restricted, because the phenomena occurring in welding are very complex and highly non-linear characteristics. To achieve the satisfactory weld bead geometry in robot welding system, the seam tracking algorithm should be reliable. The number of seam tracker was developed for arc welding automation by now. Among these seam tracker, the arc sensor is prevalently used in industrial robot welding system because of its low cost and flexibility. However, the accuracy of arc sensor would be decreased due to the electrical noise and metal transfer. In this study, the signal processing algorithm based on the neural network was implemented to enhance the reliability of measured welding current signals. Moreover, the seam tracking algorithm in conjunction with the signal processing algorithm was implemented to trace the center of weld line. It was revealed that the neural network could be effectively used to predict the welding current signal at the end of weaving.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.411-417
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• 2022

In this paper, we propose a sensor with a C-shaped load cell to detect force change when a person sitting on the chair in an electrical transport-convenience vehicle is pushing ground by both heels. The load cell built in the vehicle is mechanically deformed by the vertical force owing to the human weight and the horizontal force by ground-pushing feet. The deformation rate of the load cell and its distribution are simulated using finite element analysis. In the simulation, the applied loads are preset in the range of 10 kg - 100 kg with a step size of 10 kg, and the ground-pushing force by feet is increased to 40 N with a step size of 5 N with respect to each applied load level. The resistance change of the load cell was observed to be linear in simulation as well as in measurement. the maximum difference between simulation and measurement was 0.89 % when the strain gauge constant was 2.243. The constant has a large influence on the difference. The proposed sensor was fabricated by connecting an instrument amplifier and a microcontroller to a load cell and used to detect the force by ground-pushing feet. To detect foot driving, the reference signal was set to 130% of the load, and the duration of the sensor output signal exceeding the reference signal was set to 0.6 s. In a test of a vehicle built with the proposed sensor, the footpushing force by the worker could be successfully detected even when the worker was working.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.194-197
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• 1997

The LB technique is one of the most powerful fabricating methods of organic ultra-thin film, which deposits a monolayer films in molecular level on the surface of the substrate. We have investigated the electrical characteristics of Myristic acid, Stearic acid and Arachidic acid LB films for horizontal direction to develop for the gas sensor. The optimum conditions for a film deposition were obtained by measurement of $\pi$-A isotherm. The status of the deposited film was confirmed by measurement of UV absorbance. We could distingished the difference of I-V characteristics for the fatty acid for the horizontal direction. The conductivity of fatty acid LB films for horizontal direction was 10$^{-7}$ ~ 10$^{-9}$ [S/cm] that mean like semiconductor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.393-396
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• 1996

The electrical characteristics of stearic acid LB films far the horizontal direction were investigated to develop the gab sensor using LB films. $\pi$ -A isotherm was measured to transfer stearic acid on slide glass substrate and surface pressure for optimal deposition was 25[dyne/cm]. The deposition status of stearic acid LB films was verified by the measurement of capacitance which was increased with the number of layers. The thickness of electrode was estimated about 1000 by the I-V characteristics far the horizontal direction. The Conductivity of stearic acid LB films for horizontal direction was 10$^{-8}$ [S/cm] that mean like semiconductor.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.173-178
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• 2017

In this paper, we newly developed an omnidirectional receiver for visible light communication (VLC). The omnidirectional receiver was composed of a flexible solar cell attached on a cylindrical surface with its axis in vertical direction. The solar cell surface was symmetrical and showed an almost uniform receiving pattern in a horizontal plane. The maximum difference in a receiving pattern was within 7% of its peak value in a horizontal plane. This configuration is very easy to fabricate and useful in constructing wireless sensor networks in which one receiver needs to detect multiple LED signals in different directions.

• Journal of Sensor Science and Technology
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• v.33 no.4
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• pp.209-215
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• 2024

Generally, a straight displacement meter is used to obtain displacement data to verify the safety of structural members and structures. A straight displacement meter is also used to measure the absolute displacement in research laboratories or safety inspection sites such as bridges and buildings. In this study, for structures in which the displacement sensor could not be fixed at the location where the displacement was to be measured, a circular displacement meter was manufactured to measure the displacement by installing a displacement gauge on the structure itself. In other words, when measuring the horizontal displacement of an upper part, such as a wind tower, a circular displacement meter was installed inside the wind tower to integrate it with the structure, applying the principle that the structure itself can be used as a displacement meter. This circular displacement meter can be installed and used inside a circular structure. Whereas in the case of a telephone pole, it can be installed outside to measure displacement. It can be manufactured in various sizes and used.