• 융복합기술연구소 논문집
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• 제6권2호
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• pp.9-13
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• 2016

Robot usually requires spline motion to move through multiple knots. In this paper, catmull-rom spline method is applied to the trajectory planning of industrial robot in task space. Centripetal catmull-rom is selected to avoid self-intersection and slow motion which can be occurred in uniform and chordal spline. The method to set two control points are proposed to satisfy velocity conditions of initial and final knots. To optimize robot motion, time scaling method is presented to minimize margin between real robot value and maximum value in velocity and acceleration. The simulation results show that the proposed methods are applied to trajectory planning and robot can follow the planned trajectory while robot motion does not exceed maximum value of velocity and acceleration.

• Structural Engineering and Mechanics
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• 제55권5호
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• pp.901-911
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• 2015

The goal of this study is to investigate computational convergence of optimal solutions, with respect to optimality criteria (OC) method and methods of moving asymptotes (MMA) as optimization model for non-linear programming of material topology optimization using an acceleration method that makes design variables rapidly move toward almost 0 and 1 values. 99 line topology optimization MATLAB code uses loop vectorization and memory pre-allocation as properly exploiting the strengths of MATLAB and moves portions of code out of the optimization loop so that they are only executed once as restructuring the program. Numerical examples of a simple beam under a lateral load and a given material density limitation provide merits and demerits of the present OC and MMA for 99 line topology optimization code of continuous material topology optimization design.

• 대한기계학회논문집B
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• 제24권7호
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• pp.907-915
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• 2000

The preconditioned Krylov subspace methods were applied to the incompressible Navier-Stoke's equations for convergence acceleration. Three of the Krylov subspace methods combined with the five of the preconditioners were tested to solve the lid-driven cavity flow problem. The MILU preconditioned CG method showed very fast and stable convergency. The combination of GMRES/MILU-CG solver for momentum and pressure correction equations was found less dependency on the number of the grid points among them. A guide line for stopping inner iterations for each equation is offered.

• 한국산업융합학회 논문집
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• 제21권6호
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• pp.409-418
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• 2018

In this study, experiments were carried out after fabricating and installing a physical model considering the size of the prototype. In the model test, the number of struts placed on the wall and the applied acceleration were selected as test variables. Two different types of waves, long-period and short-period, were applied with magnitudes of 0.05g, 0.1g, 0.2g, and 0.3g. Measured are displacements at specified points. As a result of the analysis, displacement exceeding the allowable displacement of the wall occurred at an acceleration greater than 0.05g to 0.1g depending on the seismic waves applied. Therefore guidelines have to be established through further studies for aseismic design of earth retaining walls.

• 한국운동역학회지
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• 제31권1호
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• pp.44-49
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• 2021

Objective: The purpose of this study was to analyze kinematic variables according to ground slope angle during golf putting. Method: 26 collegiate golfers (age: 22.54±2.15 kg, height: 174.64±6.07 cm, weight: 71.35±9.27 kg, handicap: 5.11±4.50) were participated, and 8 motion capture cameras (250 Hz), Nexus, and Kwon3DXP software were used to collect data. It was performed repeated measures ANOVA and Bonferroni adjustment. Alpha set at .05. Results: Body alignments were not significantly different at address. Putter head trajectory and loft angle were significantly different, and AP direction of acceleration of putter head was significantly different. However, ML and SI direction of acceleration of putter head were not significantly different. Conclusion: Therefore, it was identified that ground slope angle was affected the kinematic variables during putting, and it will be performed that correlation analysis between putting success rate and kinematic variables according to ground slope angle during golf putting.

• 제어로봇시스템학회논문지
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• 제14권2호
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• pp.133-140
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• 2008

In this paper, a small and effective attitude estimation system for a humanoid robot was developed. Four small inertial sensors were packed and used for inertial measurements(3D accelerometer and three 1D gyroscopes.) An effective 3D pose estimation algorithm for low cost DSP using an extended Kalman filter was developed and evaluated. The 3D pose estimation algorithm has a very simple structure composed by 3 modules of a linear acceleration estimator, an external acceleration detector and an pseudo-accelerometer output estimator. The algorithm also has an effective switching structure based on probability and simple feedback loop for the extended Kalman filter. A special test equipment using linear motor for the testing of the 3D pose sensor was developed and the experimental results showed its very fast convergence to real values and effective responses. Popular DSP of TMS320F2812 was used to calculate robot's 3D attitude and translated acceleration, and the whole system were packed in a small size for humanoids robots. The output of the 3D sensors(pitch, roll, 3D linear acceleration, and 3D angular rate) can be transmitted to a humanoid robot at 200Hz frequency.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.85.2-85.2
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• 2005

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.145-146
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• 2005

• 대한기계학회논문집B
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• 제35권2호
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• pp.189-196
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• 2011

최근, 승용차는 물론 대형차에서도 하이브리드시스템 등의 전기동력방식을 도입하려는 연구개발이 활발하다. 기존의 내연기관을 대체하는 전기구동모터를 이용하여 차량을 구동하는 전기동력방식을 채용하는 것이 한층 더 효율적이며 가속성능, 승차감 등의 면에서도 유리한 점이 많다. 그러나 모터는 엔진과 전혀 다른 특징을 갖기 때문에 동력성능과 에너지효율에 관한 적합한 평가수법을 검토할 필요가 있다. 본 논문에서는 전기구동버스에 대한 구동모터 시스템을 다이나모미터 상에서 운전하여, 노선버스의 운행패턴을 반영한 모의운전을 실시, 가속성능 및 에너지변환효율, 회생효과의 평가방법 등을 고찰하였다. 그 결과 실 주행 패턴운전에 대한 모터일률, 전력량 등의 계측으로부터 모터 변환효율은 90% 전후, 회생전력량은 요구전력량의 40% 이상으로 평가되었다.

• 대한의용생체공학회:의공학회지
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• 제38권4호
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• pp.211-217
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• 2017

During the emergency situation such as cardiac arrest, cardiopulmonary resuscitation(CPR) is the most important treatment to maintain patient's blood circulation. Since the quality of CPR can not be easily measured or evaluated by the eye, an assistive device with an accelerometer can help to assess the pressure depth of CPR. In this study, we propose a single frequency analysis method to reduce the error of the accelerometer by extracting only one frequency component from the Fourier transform process. To verify the effectiveness of the single frequency analysis, acceleration data at CPR conditions were measured at a sampling rate of 50 / sec using a wristband equipped with an acceleration sensor. Then, We compared the existing distance estimation method and the single frequency analysis method using the measured data. The amplitude value proportional to the compression depth was obtained by applying the single frequency analysis method.