• Title/Summary/Keyword: Optimal Motion Velocity

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Development of A New Efficient Method for Controlling Robot Motion at and near Singularities (특이점 부근의 로봇운동을 효과적으로 제어하기 위한 새로운 방법 개발)

  • 정원지;최은재;홍대선;서영교;홍형표
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.6
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    • pp.31-37
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    • 2002
  • This paper presents a new motion control strategy for singularity avoidance in 6 DOF articulated robot manipulators, based on a speed limiting algorithm for joint positions and velocities. For a given task, the robot is controlled so that the joints move with acceptable velocities and positions within the reachable range of each joint by considering the velocity limit. This paper aims at the development of a new efficient method to control robot motion near and at singularities. The proposed method has focused on generating the optimal joint trajectory for a Cartesian end-effector path within the speed limit of each joint by using the speed limit avoidance as well as the acceleration/deceleration scheme. The proposed method was verified using MATLAB-based simulations.

Optimization of inlet velocity profile for uniform epitaxial growth (균일한 에피층 성장을 위한 입구 유속분포 최적화)

  • Cho W. K.;Choi D. H.;Kim M.-U.
    • 한국전산유체공학회:학술대회논문집
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    • 1998.11a
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    • pp.121-126
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    • 1998
  • A numerical optimization procedure is developed to find the inlet velocity profile that yields the most uniform epitaxial layer in a vertical MOCVD reactor. It involves the solution of fully elliptic equations of motion, temperature, and concentration; the finite volume method based on SIMPLE algorithm has been adopted to solve the Navier-Stokes equations. The overall optimization process is highly nonlinear and has been efficiently treated by the sequential linear programming technique that breaks the non-linear problem into a series of linear ones. The optimal profile approximated by a 6th-degree Chebyshev polynomial is very successful in reducing the spatial non-uniformity of the growth rate. The optimization is particularly effective to the high Reynolds number flow. It is also found that a properly constructed inlet velocity profile can suppress the buoyancy driven secondary flow and improve the growth-rate uniformity.

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Resolution of kinematic redundancy using contrained optimization techniques under kinematic inequality contraints

  • Park, Ki-Cheol;Chang, Pyung-Hun
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.69-72
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    • 1996
  • This paper considers a global resolution of kinematic redundancy under inequality constraints as a constrained optimal control. In this formulation, joint limits and obstacles are regarded as state variable inequality constraints, and joint velocity limits as control variable inequality constraints. Necessary and sufficient conditions are derived by using Pontryagin's minimum principle and penalty function method. These conditions leads to a two-point boundary-value problem (TPBVP) with natural, periodic and inequality boundary conditions. In order to solve the TPBVP and to find a global minimum, a numerical algorithm, named two-stage algorithm, is presented. Given initial joint pose, the first stage finds the optimal joint trajectory and its corresponding minimum performance cost. The second stage searches for the optimal initial joint pose with globally minimum cost in the self-motion manifold. The effectiveness of the proposed algorithm is demonstrated through a simulation with a 3-dof planar redundant manipulator.

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Impact minimization by impact ellipsoids (임팩트 타원을 이용한 임팩트의 최소화)

  • Lee, Ji-Hong;Lee, Young-Il;Yoo, Jun
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.726-729
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    • 1996
  • A weighted impact ellipsoid normalized by maximum allowable angular velocity changes is defined and compared with conventional impact ellipsoids and impact polytopes. The results shows that the conventional impact ellipsoid may give false solution as far as the optimal direction of motion is concerned.

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An Analysis of Human Motions using Video Image Processing (화상 처리기법에 의한 인체 동작분석)

  • Lee, Geun-Bu
    • Journal of the Ergonomics Society of Korea
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    • v.5 no.1
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    • pp.11-18
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    • 1986
  • The object of this research is to develop an interactive computerized graphic program for graphic output of velocity, acceleration and motion range of body task reference point. Human motions can be reproduced by scanning (rate = 1/60) the vidicon image, at same time, C.O.G of body segment group, and the results are stored in an Apple II P.C. memory. The results of this study can he exteneded to simulation and reproduction of human motions for optimal task design.

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Gain Optimization of Kinematic Control for Wire-driven Surgical Robot with Layered Joint Structure Considering Actuation Velocity Bound (와이어로 구동하는 적층형 다관절 구조를 지닌 수술 로봇의 구동 속도를 고려한 기구학적 제어기의 게인 최적화)

  • Jin, Sangrok;Han, Seokyoung
    • The Journal of Korea Robotics Society
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    • v.15 no.3
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    • pp.212-220
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    • 2020
  • This paper deals with a strategy of gain optimization for the kinematic control algorithm of a wire-driven surgical robot. The proposed controller consists of the closed-loop inverse kinematics with the back-calculation method. The closed-loop inverse kinematics has 18 PID control gains, and the back-calculation method has 6 gains. An efficient strategy is designed to optimize 18 values first and then the remaining 6 values. The optimal gain sets are searched under the step input with performance indices. In this gain optimization, the objective function is defined as the minimum value of signal-to-noise ratio of the performance indices for 6 DoF (Degree-of-Freedom) motion that is based on the Taguchi method, and the constraints are applied to obtain stable responses for each motion evenly. The gain sets obtained are verified by simulations using the test trajectories. In comparative results, the optimal gain value based on the performance index combined with ISE (integral of square error) and settling time showed the best control performance.

Development of Virtual Prototype for Labeling: Unit on the Automatic Battery Manufacturing Line (건전지 자동화 조립라인의 라벨링부의 Virtual Prototype 개발)

  • 정상화;차경래;김현욱;신병수;나윤철
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.357-362
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    • 2002
  • Most of battery industries are growing explosively as a core strategy industry for the development of the semi-conductor, the LCD, and the mobile communication device. In this thesis, dynamic characteristics of the steel can labeling machine on the automatic cell assembly line are studied. Dynamic characteristic analysis consists of dynamic behavior analysis and finite element analysis and is necessary for effective design of machines. In the dynamic behavior analysis, the displacement, velocity, applied force and angular velocity of each components are simulated according to each part. In the FEA, stress analysis, mode analysis, and frequency analysis are performed for each part. The results of these simulations are used for the design specification investigation and compensation for optimal design of cell manufacturing line. Therefore, Virtual Engineering of the steel can labeling machine on the automatic cell assembly line systems are modeled and simulated. 3D motion behavior is visualized under real-operating condition on the computer window. Virtual Prototype make it possible to save time by identifying design problems early in development, cut cost by reducing making hardware prototype, and improve quality by quickly optimizing full-system performance. As the first step of CAE which integrates design, dynamic modeling using ADAMS and FEM analysis using NASTRAN are developed.

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Video Image Processing on Apple II P.C. and Its Applications to Anthropometry and Motion Analysis (Apple II P.C.를 이용한 Video Image Processing과 인체계측 및 동작분석에의 응용)

  • Lee, Sang-Do;Jeong, Jung-Seon;Lee, Geun-Bu
    • Journal of the Ergonomics Society of Korea
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    • v.4 no.1
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    • pp.11-16
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    • 1985
  • The object of this research is to develop an Interactive Computerized Graphic Program for graphic output of velocity, acceleration and motion range of body-task reference point (e.g., C.O.G., joint location, etc.). Human motions can be reproduced by scanning (rate = 60Hz) the vidicon image, and the results are stored in an Apple II P.C. memory. The results of this study can be extended to simulation and reproduction of human motions for optimal task design.

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ROBUST CONTROLLER DESIGN FOR IMPROVING VEHICLE ROLL CONTROL

  • Du, H.;Zhang, N
    • International Journal of Automotive Technology
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    • v.8 no.4
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    • pp.445-453
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    • 2007
  • This paper presents a robust controller design approach for improving vehicle dynamic roll motion performance and guaranteeing the closed-loop system stability in spite of vehicle parameter variations resulting from aging elements, loading patterns, and driving conditions, etc. The designed controller is linear parameter-varying (LPV) in terms of the time-varying parameters; its control objective is to minimise the $H_{\infty}$ performance from the steering input to the roll angle while satisfying the closed-loop pole placement constraint such that the optimal dynamic roll motion performance is achieved and robust stability is guaranteed. The sufficient conditions for designing such a controller are given as a finite number of linear matrix inequalities (LMIs). Numerical simulation using the three-degree-of-freedom (3-DOF) yaw-roll vehicle model is presented. It shows that the designed controller can effectively improve the vehicle dynamic roll angle response during J-turn or fishhook maneuver when the vehicle's forward velocity and the roll stiffness are varied significantly.

A Design of Anti-sway Controller for Container Crane (컨테이너 크레인의 흔들림 억제 제어기 설계)

  • Son, J.K.;Kwon, S.J.;Park, H.S.
    • Journal of Power System Engineering
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    • v.7 no.1
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    • pp.51-59
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    • 2003
  • The recent amount of container freight continuously has been increased, but the low efficiency of container crane causes jamming frequently in transportation and cargo handling at port. It is required that the working velocity and safety are improved by control of moving the trolley as quick as possible without large overshoot and any residual swing motion of container at the destination. In this paper, a LQ Fuzzy controller for a container crane is proposed to accomplish an optimal design of improved control system for minimizing the swing motion at destination. In this scheme a mathematical model for the system is obtained in state space form. Finally, the effectiveness of the proposed controller is verified through computer simulation.

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