• The Journal of Korean Physical Therapy
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• 제28권1호
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• pp.14-21
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• 2016

Purpose: The purpose of this study was to investigate examine how the kinematics and kinetics of lower limb joints were changed depending on the unstable shoes (US) during sit-to-stand task (SitTS). Methods: Nineteen healthy females were participated in this study. The subjects performed sit-to-stand task with US and barefoot. The experiment was repeated three times for each tasks with conditions. The kinematics and kinetics of lower limb joint were measured and analyzed using a 3-D motion analysis system. A paired t-test was utilised performed for to identificationy of changes in mean of angle, force, and moment between both the two conditions. Results: The results of this study showed kinematic differences in lower limb joints during SitTS based on the US. The hip, knee, and ankle angle showed statistically significant differences during SitTS. At the initial of SitTS, Tthe force and moment of the hip flexor, hip extensor, knee flexor, knee extensor, ankle flexor, and ankle extensor showed statistically significant differences. At the terminal of SitTS, Tthe force and moment of the hip flexor, hip extensor, knee flexor, knee extensor, ankle flexor, and ankle extensor showed statistically significant differences. At the maximum of SitTS, Tthe moment of the hip extensor showed statistically significant differences. The force and moment of the ankle flexor, extensor moment showed statistically significant differences. Conclusion: Therefore, Wwearing US is considered to influence on the lower limb joints kinematics and kinetics during SitTS movements, and thus suggests the possibility that of reducing the risks of pain, and osteoarthritis caused by changes in the loading of lower limb joints.

• 제어로봇시스템학회논문지
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• 제19권12호
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• pp.1105-1110
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• 2013

In this paper, a robot arm capable of recognizing and drawing various line thicknesses is developed. Conventional line drawing robots are not capable of adjusting the thickness of lines. However, to draw faster and to enrich the expression of line drawing robots, it is necessary to adjust line thickness using a brush pen. Simple images are acquired and various line thicknesses are recognized by image processing. Trajectories of lines are generated with distance sorting using thinning and corner point detections for each label. Information on line thickness and trajectory is sent to the controller of a robot arm taking into consideration 2D inverse kinematics. Through this process, the robot arm can draw various lines thicknesses along 2D trajectories with 3 motors. Robot arm for detailed drawing will be studied in the future.

• 대한정형외과스포츠의학회:학술대회논문집
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• 대한정형외과스포츠의학회 2004년도 The 7th korea-japan joint meeting of orthopaedic sports medicine
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• pp.3-3
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• 2004

• Structural Engineering and Mechanics
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• 제62권1호
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• pp.33-42
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• 2017

We present in this paper a finite element formulation for nonlinear torsional analysis of 3D beams with arbitrary composite cross-sections. Since the proposed formulation employs a continuum mechanics based beam element with kinematics enriched by the extended St. Venant solutions, it can precisely account higher order warping effect and its 3D couplings. We propose a numerical procedure to calculate the extended St. Venant equation and the twisting center of an arbitrary composite cross-section simultaneously. The accuracy and efficiency of the proposed formulation are thoroughly investigated through representative numerical examples.

• 센서학회지
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• 제32권5호
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• pp.300-306
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• 2023

A hull-cleaning robot sticks to the surface of a vessel and moves for efficient cleaning. Precise path planning and tracking using the current position is crucial. Many robots rely on the INS algorithm, but errors accumulate. To fix this, GPS, sonar, and USBL are used, though with limitations. Selecting suitable sensors for the surface operation and accurate positioning algorithm are vital. In this study, we developed a robot position estimation algorithm using the structure of a ship. Problems that arise when expanding the 2D position estimation algorithm used in existing wall structures to 3D were evaluated and methods for solving them were proposed. In addition, we aimed to improve performance by deriving singularities that exist in the robot path and proposing an error correction algorithm based on the singularities.

• 한국CDE학회논문집
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• 제6권2호
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• pp.69-77
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• 2001

This paper describes a method of calculating the feedrate for the constant cutting speed at a CL-point in 5-axis machining. Unlike 3-axis machining, 5-axis machining has the flexibility of the tool motions due to two rotation axes. But the feedrate at joint space differs from the feedrate at a tool tip(the CL-point) of the 3D Euclidean space for the tool motions. The proposed algorithm adjusts the feedrate based on 5-axis NC data, the kinematics of a machine, and the tool length. The following calculations is processed for each NC block to generate the new feedrate; 1) calculating the moving distance at the CL-point, 2) calculating the moving time by the given feedrate, 3) calculating the feedrate of each axis, 4) getting the new feedrate. The proposed algorithm was applied to a 5-axis machine which had a tilting spindle and a rotary table. Totally, the result of the algorithm reduced the machining time and smoothed the cutting-load by the constant cutting speed at the CL-point.

• 정보처리학회논문지B
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• 제13B권2호
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• pp.187-196
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• 2006

대부분의 3차원 캐릭터 애니메이션에서는 모션 캡쳐 장비를 통해서 포착된 동작 데이터를 이용하여 다양한 지형상에서 캐릭터의 이동 동작을 표현한다. 이러한 동작 포착 데이터는 실제 사람과 같이 움직이는 동작들을 자연스럽게 표현할 수 있으나, 만약 다양한 지형에 대해 움직이는 동작을 표현할 경우, 지형의 유형에 따라 모든 동작을 캡쳐하여야 하고, 얻어진 동작 데이터를 다른 유형의 캐릭터에 적용할 경우 동작 데이터를 다시 얻거나 기존 동작 데이터를 재편집해야 하는 어려움이 있다. 따라서 본 연구에서는 평지면, 경사면, 계단면 그리고 굴곡면 등 다양한 지형에서의 적응적인 걷기, 달리기의 이동 동작을 생성하기 위한 통합적 생성 방법을 제안한다. 이 방법에서는 캐릭터의 신장이나 걷는 속도 걸음폭 등의 적은 매개변수들을 사용하여 이동 동작을 생성할 수 있다. 관절들의 위치나 각도는 역운동학(Inverse Kinematics)방법으로 계산하고, 골반과 이동하는 다리의 움직임 궤적 산출은 큐빅 스플라인 곡선을 활용한다. 또한 제안된 방법을 통해서 다양한 실제 캐릭터에 적용하여 이동 동작을 확인한다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제30권11호
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• pp.1092-1101
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• 2003

대부분의 3차원 캐릭터 애니메이션에서는 모션 캡쳐 장비를 통해서 포착된 동작 데이타를 이용하여 다양한 지형상에서 캐릭터가 걷는 동작을 표현한다. 이러한 동작 포착 데이타는 실제 사람과 같이 움직이는 동작들을 자연스럽게 표현할 수 있으나, 만약 다양한 지형에 대한 움직이는 동작이 표현할 경우, 지형의 유형에 따라 모든 동작을 캡쳐하여야 하고, 얻어진 동작 데이타를 다른 유형의 캐릭터에 적용할 경우 동작 데이타를 다시 얻거나 기존 동작 데이타를 재편집해야 하는 어려움이 있다. 따라서 본 연구에서는 적은 매개변수들을 사용하여 평지면, 경사면, 계단면 그리고 굴곡면 등 다양한 지형에서의 적응적인 걷는 동작을 생성하기 위한 방법과 골반과 이동하는 다리의 움직임 제적을 산출하는 방법을 제안한다. 이 방법에서는 캐릭터의 신장이나 걷는 속도, 걸음폭 등의 매개변수들을 조절하여 다양한 걸음걸이를 생성할 수 있으며 역운동학(Inverse Kinematics) 개념을 적용하여 관절들의 위치나 각도를 산출하고 관절의 이동 궤적을 계산하기 위해 큐빅 스플라인 곡선을 활용한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1593-1596
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• 1997

Because the leg mechanism of walking roblt affect on the mobility and energy efficiency, we focus on the design of new leg mechanism based on the previous leg mechanisms. We mention the deficiency of the previous leg mechanisms and propose a new leg mechanism that consists of a 2-d.o.f pantograph mechanism and a vertical linear actuator. The pantograph mechanism is attached to the horizontal plane of the body and the verical linear actuator is vertical to that plane. In order to design a quadruped walking robot, we consider the kinematics of the 2-d.o.f pantograph mechanism and the arrangement of twol linear motion guides that drive the pantograph mechanism.

• 로봇학회논문지
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• 제2권2호
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• pp.129-136
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• 2007

This paper introduces a position-based robust visual servoing method which is developed for operation of a human-like robot with two arms. The proposed visual servoing method utilizes SIFT algorithm for object detection and CAMSHIFT algorithm for object tracking. While the conventional CAMSHIFT has been used mainly for object tracking in a 2D image plane, we extend its usage for object tracking in 3D space, by combining the results of CAMSHIFT for two image plane of a stereo camera. This approach shows a robust and dependable result. Once the robot's task is defined based on the extracted 3D information, the robot is commanded to carry out the task. We conduct several position-based visual servoing tasks and compare performances under different conditions. The results show that the proposed visual tracking algorithm is simple but very effective for position-based visual servoing.