• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.246-249
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• 2005

The TFT-LCD is extensively used from a small watch to a large TV display, and the demand is increasing rapidly. The size of R-LCD glass plate becomes more bigger, and the thickness become more thinner with high demands. As a result natural frequency of the TFT-LCD glass plate becomes more lower. The TFT-LCD glass plate will be moved by robot arm and may receive effect of vibration that occur at transfer. Natural frequency of the TFT-LCD glass plate is increased or decrease according to location that robot arm fixs glass plate. Purpose of a this study is finding support location that optimize the first natural frequency of TFT-LCD glass plate. The size optimization method of ANSYS 8.0 is used as the optimization tool search on the optimal support location of TFT-LCD glass plate. The considered number of support point is from 4 to 9.

• The Journal of Korea Robotics Society
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• v.7 no.1
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• pp.29-34
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• 2012

This paper suggests a new observation model for Extended Kalman Filter based Simultaneous Localization and Mapping (EKF-SLAM). Since the EKF framework linearizes non-linear functions around the current estimate, the conventional line model has large linearization errors when a mobile robot locates faraway from its initial position. On the other hand, the model that we propose yields less linearization error with respect to the landmark position and thus suitable in a large-scale environment. To achieve it, we build up a three-dimensional space by adding a virtual axis to the robot's two-dimensional coordinate system and extract a plane by using a detected line on the two-dimensional space and the virtual axis. Since Jacobian matrix with respect to the landmark position has small value, we can estimate the position of landmarks better than the conventional line model. The simulation results verify that the new model yields less linearization errors than the conventional line model.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3016-3018
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• 2005

The PSD(Position Sensitive Detector) is a sensor for detecting the position of incident light. Because of its various advantages, it is used for position and angle sensing, optical range finders, laser displacement sensing, and etc. In the previous study of the position finding system, the laser tracking robot is developed. Small data rate and unidirectionality is the characteristics of data communication both DSP-based pan/tilt control board and the robot. If we can transmit data to the target using PSD sensor and laser diode module, there is no need for communication devices such as the bluetooth and wireless module. For this reason, this paper presents the new method for data transmission. Transmit data using RS-232 is modulated by a VTF(Voltage To Frequency) converter The laser diode module transmits the modulated data. And then the PSD sensor receive that data. Demodulation process is accomplished by the system which is consisted with trans-impedance amplifier, FTV(Frequency To Voltage) converter, and etc.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1808-1813
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• 2005

In this paper, we present the finger tip tactile sensor which can detect contact normal force as well as slip. The developed sensor is made of two different materials, such as polyvinylidene fluoride(PVDF) that is known as piezoelectric polymer and pressure variable resistor ink. In order to detect slip to surface of object, a PVDF strip is arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, we developed a tactile sensing system by miniaturizing the charge amplifier, in order to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.2
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• pp.228-233
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• 2004

Nowadays, the robot with various and complex functions is required. previous algorithms, however, cannot satisfy the requirement. In order to solve these problems, we introduce the 2-Layer Fuzzy Controller, which has a small number of fuzzy rules corresponding to various inputs and outputs. Also, it controls robustly and effectively an object. The main problem in the fuzzy controller is how to design the fuzzy rule. This paper designs the optimal 2-layer fuzzy controller using the Schema Co-Evolutionary Algorithm. The schema co-evolutionary algorithm can find more rapidly and excellently than simple genetic algorithm does.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.10
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• pp.936-943
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• 2015

This paper presents arc/line segments-based Simultaneous Localization and Mapping (SLAM) by updating accumulated laser sensor data with a mobile robot moving in an unknown environment. For each scan, the sensor data in the set are stored by a small constant number of parameters that can recover the necessary information contained in the raw data of the group. The arc and line segments are then extracted according to different limit values, but based on the same parameters. If two segments, whether they are homogenous features or not, from two scans are matched successfully, the new segment is extracted from the union set with combined data information obtained by means of summing the equivalent parameters of these two sets, not combining the features directly. The covariance matrixes of the segments are also updated and calculated synchronously employing the same parameters. The experiment results obtained in an irregular indoor environment show the good performance of the proposed method.

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.1-7
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• 2014

Generally, buck converter controller is designed to control the output voltage of the converter. However, design of the controller in a photovoltaic power conditioning system is different from theoretical design guideline. The controller in a photovoltaic power conditioning system controls the input voltage of the converter (the output voltage of the solar cell) to meet a maximum power point tracking (MPPT) performance. In this study, a new model for buck converter used in a photovoltaic power conditioning system is proposed, which is linearized after state-space averaging in each period. Also, mathematical expression of the modeled buck converter is interpreted separately as small and large signals; therefore its appropriateness is measured to design linear voltage and current controller.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.547-554
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• 2013

This paper proposes a novel formation algorithm of identical robots based on object tracking method using omni-directional images obtained through fisheye lenses which are mounted on the robots. Conventional formation methods of multi-robots often use stereo vision system or vision system with reflector instead of general purpose camera which has small angle of view to enlarge view angle of camera. In addition, to make up the lack of image information on the environment, robots share the information on their positions through communication. The proposed system estimates the region of robots using SURF in fisheye images that have $360^{\circ}$ of image information without merging images. The whole system controls formation of robots based on moving directions and velocities of robots which can be obtained by applying Lucas-Kanade Optical Flow Estimation for the estimated region of robots. We confirmed the reliability of the proposed formation control strategy for multi-robots through both simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.399-399
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• 2000

In this paper, path generation using the sensor platform is proposed. The sensor platform is composed two electric motors which make panning and tilting motions. An algorithm fur a real path form and an obstacle length is realized using a scanning algorithm to rotating the sensors on the sensor platform. An ARV (Autonomous Robot Vehicle) is able to recognize the given path by adapting this algorithm. In order for the ARV to navigate the path flexibly, a kinematic model needed to be constructed. The kinematic model of the ARV was reformed around its body center through a relative velocity relationship to controllability, which derives from the nonholonomic characteristics. The optimal controller that is based on tile kinematic model is operated purposefully to track a reference vehicle's path. The path generation algorithm is composed of two parks. On e part is the generating path pattern, and the other is used to avoid an obstacle. The optimal controller is used for tracking the reference path which is generated by recognizing the path pattern. Results of simulation show that this algorithm for an ARV is sufficient for path generation by small number of sensors and for low cost controller.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1195-1200
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• 2013

In recent years, variable stiffness actuation has attracted much attention because interaction between a robot and the environment is increasingly required for various robot tasks. Several variable stiffness actuators (VSAs) have been developed; however, they find limited applications owing to their size and weight. For realizing their widespread use, we developed a compact and lightweight mini-VSA. The mini-VSA consists of a control module based on an adjustable moment arm mechanism and a drive module with two motors. By controlling the relative motion of cams in the control module, the position and stiffness can be simultaneously controlled. Experimental results are presented to show its ability to change stiffness.