• 정보처리학회논문지:소프트웨어 및 데이터공학
• /
• 제5권5호
• /
• pp.243-250
• /
• 2016

최근 가상현실(VR, virtual reality)이나 증강현실(AR, augmented reality)이 주목받으면서 이에 관한 컴퓨터 그래픽스(computer graphics)연구들이 활발히 진행되고 있다. 특히, 인간의 동작을 가상의 공간에서 구현하는 방법에 관한 연구들이 활발히 진행되고 있다. 하지만 많은 연구가 인간의 일반적인 동작에 한정되어 있다. 본 연구에서는 역운동학(IK, inverse kinematics)을 이용한 스포츠클라이밍 자세생성과 동작제어를 통해 인간의 일반적인 동작 이외에 스포츠클라이밍과 같은 특수 목적의 다양한 동작들을 삼차원의 가상공간에서 가상 인물(virtual character)의 자세 및 동작을 생성하는 시스템을 제안한다. 역운동학(IK, inverse kinematics) 기법을 통한 자세 생성은 역운동학 함수(IK function)와 실제 데이터를 통한 기본자세 애니메이션을 제작, 이를 활용하여 사실성을 더하고 자연스러운 자세 및 동작을 생성한다. 본 논문에서는 스포츠 클라이밍의 기본동작을 이용하여 올바른 자세와 함께 실제와 유사한 동작을 생성하는 시스템을 설계하였다. 이를 통해 클라이머를 위한 학습 프로그램이나 클라이밍 게임 같은 다양한 형태의 스포츠 클라이밍 콘텐츠를 제작하는데 도움이 되고자 한다.

• 생물환경조절학회지
• /
• 제13권1호
• /
• pp.1-7
• /
• 2004

본 연구는 오이수확기의 매니퓰레이터 개발을 위한 기구학적 분석을 하는 것이다. 매니퓰레이터의 정방향 기구학 및 역방향 기구학 분석을 한 후 실제 장치의 반복오차 측정실험을 통해 이론 값을 검증하였다. 매니퓰레이터는 총 세 개의 링크로서 한 개의 수직링크와 두 개의 호전링크로 구성되어져 있으며, 세 개의 스테핑 모터가 각 관절에 장착되어 링크에 동력을 전달한다. 주요 연구결과를 요약하면 다음과 같다. D-H Parameter를 이용하여 정방향 기구학에 의한 매리퓰레이터의 변환 연산자를 얻었다. 역방향 기구학의 해는 두가지로 나타났으며 삼각함수를 이용하여 해를 구하였다. 매리퓰레이터의 반복오차를 측정한 검증 실험에서는 X, Y, Z축에 대하여 반복 오차가 최대 2.60mm, 2.05mm, 1.55mm로 나타났으며, 정방향 및 역방향 기구학에서 오차의 최대지점 및 최소지점의 실제 좌표는 일치하였다. 반복오차 측정 결과는 매리퓰레이터의 목표지점인 오이의 직경에 비해 비교적 작게 나타났다. 측정오차는 실험중 발생한 실험오차로 판단된다. 매니퓰레이터의 오차를 줄이고 작업능률의 향상을 위해서는 링크의 수를 줄이고 오이의 품종 및 재배환경을 고려하여야 하며, 경량이면서도 견고한 재료를 사용하여 하중을 줄여야 한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.869-874
• /
• 2004

The inverse kinematics of five-axis milling machines produce large errors near stationary points of the required surface. When the tool travels cross or around the point the rotation angles may jump considerably leading to unexpected deviations from the prescribed trajectories. We propose three new algorithms to repair the trajectories by adjusting the rotation angles in such a way that the kinematics error is minimized. Given the tool orientations and the inverse kinematics of the machine, we first eliminate the jumping angles exceeding ${\pi}$ by using the angle adjustment algorithm, leaving the jumps less than ${\pi}$ to be further optimized. Next, we propose to apply an angle switching algorithm to compute the rotations and identify an optimized sequence of rotations by the shortest path scheme. Further error reduction is accomplished by the angle insertion algorithm based an o special interpolation to obtain the required rotations near the singularity. We have verified the algorithms by five-axis milling machines, namely, MAHO600E at the CIM Lab of Asian Institute of Technology and HERMLE UWF902H at the CIM Lab of Kasetsart University.

• 대한기계학회논문집A
• /
• 제28권10호
• /
• pp.1574-1582
• /
• 2004

Binary manipulators have recently received much attention due to hyper-redundancy, light weight, good controllability and high reliability. The precise positioning of the manipulator end-effecter requires the use of many modules, which results in a high-dimensional workspace. When the workspace dimension is large, existing inverse kinematics methods such as the Ebert-Uphoff algorithm may require impractically large memory size in determining the binary positions of all actuators. To overcome this limitation, we propose a new inverse kinematics algorithm: the inverse kinematics problem is formulated as an optimization problem using real-valued design variables, The key procedure in this approach is to transform the integer-variable optimization problem to a real-variable optimization problem and to push the real-valued design variables as closely as possible to the permissible binary values. Since the actual optimization is performed in real-valued design variables, the design sensitivity becomes readily available, and the optimization method becomes extremely efficient. Because the proposed formulation is quite general, other design considerations such as operation power minimization can be easily considered.

• 한국정밀공학회지
• /
• 제14권7호
• /
• pp.144-153
• /
• 1997

The inverse kinematics problem of a reclaimer which excavates and transports raw materials in a raw yard is investigated. Because of the geometric feature of the equipment in which scooping buckets are attached around the rotating disk, kinematic redundancy occurs in determining joint variable. Link coordinates are introduced following the Denavit-Hartenbery representation. For a given excavation point the forward kinematics yields 3 equations, however the number of involved joint variables in the equations is four. It is shown that the rotating disk at the end of the boom provides an extra passive degree of freedom. Two approaches are investigated in obtaining inverse kinematics solutions. The first method pre-assigns the height of excavation point which can be determined through path planning. A closed form solution is obtained for the first approach. The second method exploits the orthogonality between the normal vector at the excavation point and the z axis of the end-effector coordinate system. The geometry near the reclaiming point has been approximated as a plane, and the plane equation has been obtained by the least square method considering 8 adjacent points near the point. A closed form solution is not found for the second approach, however a linear approximate solution is provided.

• 한국지능시스템학회논문지
• /
• 제17권7호
• /
• pp.862-868
• /
• 2007

일반적으로 인간손에 있는 검지 손가락의 평면운동은 3개의 관절운동에 의해 이루어진다. 이러한 운동을 위해서는 기본적으로 역기구학 문제를 풀어야 하는데, 이것은 로봇 손을 이용한 파지나 조작행위에 있어서 필수적이다. 따라서 본 논문에서는 이러한 로봇 손가락의 역기구학 문제를 지능적으로 해결할 수 있는 뉴럴 러닝에 기반한 방법을 제안하고자 한다. 제안된 방법은 뉴럴 러닝에 있어서 동적인 학습율을 적용함으로써 보다 빠른 학습이 가능하고, 생체모방에 근거한 인간 손가락의 운동특성을 고려하는 것이 특징이다. 제안된 방법의 유용성을 입증하기 위하여 시뮬레이션을 수행한다.

• 한국운동역학회지
• /
• 제31권2호
• /
• pp.79-86
• /
• 2021

Objective: The purpose of this study was to identify the effect of reduced plantar cutaneous sensation on gait kinematics during walking with and without CAI. Method: A total of 20 subjects involved in this study and ten healthy subjects and 10 CAI subjects participated underwent ice-immersion of the plantar aspect of the feet before walking test in this study. The gait kinematics were measured before and after ice-immersion. Results: We observed a before ice-immersion on plantar cutaneous sensation, CAI subject were found to reduced ankle dorsiflexion, knee external rotation, hip adduction, and internal rotation compared to control subject. After ice-immersion, CAI subjects were found to reduce knee external rotation, hip adduction. However, no significant ankle joint kinematics. Conclusion: While walking, gait pattern differences were perceived between groups with and without plantar cutaneous sensation. The results of the study may explain the abductions in the hip angle movements in CAI patients at initial contact compared to healthy subjects in the control group when plantar cutaneous sensation was reduced. A change in proximal joint kinematics may be a conservative strategy to promote normal gait patterns in CAI patients.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.557-562
• /
• 1991

In this paper, we present new methods for solving the inverse kinematics associated with 6 degree of freedoms manipulator by the numerical method. This method will be based on tracking stability of special nonlinear dynamical systems, and differs from the typical techniques based by the Newton-Gauss or Newton-Raphson method for solving nonlinear equations. This simulation results show that the new method is solving the inverse kinematics of PUMA 560 without the derivative of a given task space trajectories.

• Transactions on Control, Automation and Systems Engineering
• /
• 제4권2호
• /
• pp.156-163
• /
• 2002

This paper presents a new formulation to simplify the three resulting constraint equations of the direct kinematics of the 3-6 (Stewart-Gough) Platform. The conventional direct kinematics of the 3-6 Platform has been formulated through complicated steps with trigonometric functions in three angle variables and thus results in the computational burden. In order to reduce the formulation complexity, we replace an angle variable into a length one and express three connecting joints on the moving platform in the same frame. The proposed formulation yields considerable abbreviation of the number of the calculation terms involved in the direct kinematics. It is verified through a series of simulation results.

• 천문학회보
• /
• 제40권1호
• /
• pp.78.4-79
• /
• 2015

We present the spatially resolved kinematics of ionized gas and stars along the major axis of 9 pseudo bulge galaxies. Using the high quality long-slit spectra obtained with the FOCAS at the Subaru telescope, we measured the flux, velocity, and velocity dispersion of the [OIII] and $H{\beta}$ lines to determine the size of the narrow-line region, rotation curve, and the radial profile of velocity dispersions. We compare ionized gas kinematics and stellar kinematics to investigate whether ionized gas shows any signs of outflows and whether stars and ionized gas show the same sigma-dip feature (i.e., decrease of velocity dispersion) at the very center.