• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1884-1885
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• 2011

In the wireless sensor network (WSN) environment, the approximate point-in-triangulation (APIT) is a kind of range-free localization algorithm. This algorithm provides high precision, however, the coverage rate is somewhat poor. In this paper, we propose an improved APIT algorithm for the localization of swarm robots, which is based on the received signal strength indicator (RSSI) and the center of gravity (COG) methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1190-1193
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque, so that the estimation of damping property from the isokinetic movement is difficult.

• Journal of Advanced Navigation Technology
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• v.4 no.2
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• pp.132-142
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• 2000

This paper includes a study on the performance analysis of SDINS by a simulator using Matlab/Simulink. The performance model is considered gravity and Coriolis force, and a barometer is included to damp down diversity of a perpendicular axis error. Using the simulator, the performance included gyro sensor errors was analyzed in various maneuvering patterns. Also, the performance is virtually presented for the variation of error parameters of gyro and accelerometer under GUI.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.18-26
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• 2011

This paper presents a method, Exposure Controlled Temporal Filtering (ECF), applied to visual motion tracking, that can cancel the temporal aliasing of periodic vibrations of cameras and fluctuations in illumination through the control of exposure time. We first present a theoretical analysis of the exposure induced image time integration process and how it samples sensor impingent light that is periodically fluctuating. Based on this analysis we develop a simple method to cancel high frequency vibrations that are temporally aliased onto sampled image sequences and thus to subsequent motion tracking measurements. Simulations and experiments using the 'Center of Gravity' and Normalized Cross-Correlation motion tracking methods were performed on a microscopic motion tracking system to validate the analytical predictions.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.757-758
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• 2008

This paper aims to propose an emergency recognition system using multimodal information extracted by an image processing module, a voice processing module, and a gravity sensor processing module. Each processing module detects predefined events such as moving, stopping, fainting, and transfer them to the multimodal integration module. Multimodal integration module recognizes emergency situation by using the transferred events and rechecks it by asking the user some question and recognizing the answer. The experiment was conducted for a faint motion in the living room and bathroom. The results of the experiment show that the proposed system is robust than previous methods and effectively recognizes emergency situations at various situations.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.366-369
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• 1992

In this paper we propose a 3-dimensional formation system using an arc welding robot. The principle of our system is just only to accumulate welding beads, so that the target 3-dimensional surfaces can be built up. Considering the effects of the gravity on the arc welding, the welding torch is steadily clamped and the position and the posture of the target board on which target work is formed is controlled by a 6-axis robot hand. Movements of the target board are controlled considering the 3dimensional shape of the target and the accumulating speed of the welding bead. In order to realize such systems, a distance sensor is mounted on the tip of the robot hand. And a coordinate transformation technique is employed

• ICROS
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• v.16 no.3
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• pp.40-45
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• 2010

물체의 운동을 측정하기 위하여 관성 센서(inertial sensor)에 대한 배경 지식이 없는 사용자가 가속도계(accelerometer)를 사용하고자 할 경우 센서의 이름이 주는 혼동에 의하여 물체의 운동 가속도(acceleration)를 쉽게 얻어낼 수 있으리라 기대하게 된다. 반면, 가속도계가 실제 측정하여 주는 값은 비력 가속도(acceleration due to specific force)에 해당되므로 적절한 처리를 부가하지 않으면 기대한 바와 같이 물체의 운동 가속도를 얻을 수 없다. 가속도계의 측정값으로부터 운동 가속도를 추출하기 위해서는 중력장 가속도 (gravitational acceleration), 중력 가속도 (acceleration due to gravity), 비력 가속도, 그리고 운동 가속도 사이의 관계를 명확하게 구분 이해할 필요가 있다. 본 고에서는 앞선 고들에서 다룬(막대) 벡터, 좌표값, 좌표계, 좌표변환행렬, 그리고 코리올리 효과 등의 개념을 확장하여 다양한 개념의 가속도들을 구분 설명하였다.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.77-84
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• 2006

This paper describes the design and implementation of a robot's gripper control system. In order to safely grasp an unknown object using the robot's gripper, the gripper should detect the force of gripping direction and the force of gravity direction, and should perform the force control using the detected forces and the robot's gripper control system. In this paper, the robot's gripper control system is designed and manufactured using DSP(Digital Signal Processor), and the gripper is composed of two 6-axis force/moment sensors which measures the Fx force(force of x-direction), Fy force, Fz force, and the Mx moment(moment of x-direction), My moment, Mz moment at the same time. The response characteristic test of the system is performed to determine the proportional gain Kp and the integral gain Ki of PI controller. As a result, it is shown that the developed robot's gripper control system grasps an unknown object safely.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.170-171
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• 2017

오늘날 바쁜 일상에 따라 화분관리의 어려움을 많이 느꼈다. 따라서 Raspberry, Arduino를 이용한 사용자 지향적인 화분관리시스템을 목표로 두고 개발 하여 체계화, 단순화, 간편화하였다. 본 논문은 현재 가장 많이 사용하는 습도 센서(Gravity: Analog Soil Moisture Sensor For Arduino)와 워터펌프(Peristaltic Liquid Pump with Silicone Tubing) 중심으로 개발하였다. 또한 편의성과 휴대성, 접근성에 수익성까지를 고려하여 앱을 구현, 이용함으로써 사용자에게 화분 관리에 대한 정보 관리를 용이하도록 하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.2
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• pp.160-167
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• 2001

This paper presents control and evaluation of a new haptic device with a 6-DOF parallel mechanism for interfacing with virtual reality. This haptic device has low inertial, high bandwidth compactness, and high output force capability mainly due to of base-fixed motors. It has also wider orientation workspace mainly due to a RRR type spherical joint. A control method is presented with gravity compensation and with force feedback by an F/T sensor to compensate for the effects of unmodeled dynamics such as friction and inertia. Also, dynamic performance has been evaluated by experiments. for force characteristics such as maximum applicable force, static-friction force, minimum controllable force, and force bandwidth Virtual wall simulation with the developed haptic device has been demonstrated.