• Title, Summary, Keyword: Kinematic Constraints

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Development of a Kinematic Winding Control Algorithm for the Alternate Pirn (Alternate Pirn의 권취형상 제어를 위한 기구학적 제어 알고리즘 개발)

  • 최영휴;김광영;김종수;박대원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.413-418
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    • 1996
  • Alternate pirn winding is more difficult to control than others because starting points of its traverse strokes are changed alternately through the winding operations. However, the alternate pirn winding is ye useful method because the yarn can be hardly broken when it is unwinded from full packaged bobbin. This paper presents kinematic control algorithm for the alternate pirn. The proposed algorithm can decide the values of control variables such as bobbin speed and traverse speed from the given input parameters and constraints by using the kinematic relations of the winding mechanism. The compute simulations and experimental verifications of the developed winding control algorithm are carried out It is concluded that the proposed algorithm is an efficient and reliable alternative to traditional trial and error control methods.

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A NUMERICAL ALGORITHM FOR KINEMATIC ANALYSIS OF THE MACPHERSON STRUT SUSPENSION SYSTEM USING POINT COORDINATES

  • Attia, Hazem Ali
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.8 no.1
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    • pp.67-80
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    • 2004
  • In the present paper, a numerical algorithm for the kinematic analysis of a MacPherson strut motor-vehicle suspension system is developed. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. The presented formulation in terms of this system of coordinates is simple and involves only elementary mathematics. The resulting constraint equations are mostly either linear or quadratic in the rectangular Cartesian coordinates. The proposed formulation eliminates the need to write redundant constraints and allows to solve a reduced system of equations which leads to better accuracy and a reduction in computing time. The algorithm is applied to solve the initial positions as well as the finite displacement, velocity and acceleration problems for the MacPherson strut motor-vehicle suspension system.

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Development of an Efficient Vehicle Dynamics Model Using Massless Link of a Suspension (현가장치 무질량 링크를 이용한 효율적인 차량동역학 모델 개발)

  • Jung Hongkyu;Kim Sangsup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.1
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    • pp.99-108
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    • 2005
  • This paper represents an efficient modeling method of a suspension system for the vehicle dynamic simulation. The suspension links are modeled as composite joints. The motion of wheel is defined as relative one degree of freedom motion with respect to car body. The unique relative kinematic constraint formulation between the car body and wheel enables to derive equations of motion in terms of wheel vertical motion. Thus, vehicle model has ten degrees of freedom. By using velocity transformation method, the equations of motion of the vehicle is systematically derived without kinematic constraints. Various vehicle simulation such as J-turn, slowly increasing steer, sinusoidal sweep steer and bump run has been performed to verify the validity of the suggested vehicle model.

Kinematic Control of Redundant Robots in the Constrained Environment and Its Applicaiton to a Nozzle Dam Installation/Detachment Task in Nuclear Power Plants (구속된 환경에서의 여유자유도 로봇의 기구학적 제어와 원자력 발전소 노즐댐 장 /탈착작업에의 적용)

  • Park, Ki-Cheol;Chang, Pyung-Hun;Kim, Seung-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.12
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    • pp.3871-3882
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    • 1996
  • In this paper, a closed-form formulation for inverse kinematics of robot manipulators with kinematic redundancy under the constrained environment has been derived using the Kuhn-Tucker condition, the extended Lagrange multiplier method and the working set method. The proposed algorithm satisfies the necessaryand sufficient conditions for optimization subject to equality and inequality constraints. In addition, computationally efficient kinematic control methods have been proposed using differential kinemetics and gradient projection mehtod. The effectiveness of the proposed methods has been demonstrated with a 4-dof planar robot, and then a 7-dof spatial robot as a practical application to the nozzle dam task in the Nuclear Power Plant.

Optimum Design for Reducing Steering Error of Rack-and-Pinion Steering Linkage (랙-피니언 조향기구의 조향오차 최적설계)

  • 홍경진;최동훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.2
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    • pp.43-53
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    • 1998
  • This paper addresses an optimization for reducing a steering error of a rack-and-pinion steering linkage with a MacPherson strut independent front suspension system. The length, orientations and inner joint positions of a tie-rod are selected as design variables and Ackerman geonetry, understeer effect, minimum turn radius, wheel alignment and packaging are considered as design constraints. Nonlinear kinematic analysis of the steering system is performed for calculating the values of cost and constraints, and Augmented Lagrange Multiplier(ALM) method is used for solving the constrained optinization problem. The optimization results show that the steering error are considerably reduced while satisfying all the constraints.

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Path Planning for Autonomous Mobile Robots by Modified Global DWA (수정된 전역 DWA에 의한 자율이동로봇의 경로계획)

  • Yoon, Hee-Sang;Park, Tae-Hyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.2
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    • pp.389-397
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    • 2011
  • The global dynamic window approach (DWA) is widely used to generate the shortest path of mobile robots considering obstacles and kinematic constraints. However, the dynamic constraints of robots should be considered to generate the minimum-time path. We propose a modified global DWA considering the dynamic constraints of robots. The reference path is generated using A* algorithm and smoothed by cardinal spline function. The trajectory is then generated to follows the reference path in the minimum time considering the robot dynamics. Finally, the local path is generated using the dynamic window which includes additional terms of speed and orientation. Simulation and experimental results are presented to verify the performance of the proposed method.

Dynamic Manipulability for Cooperating Multiple Robot Systems (공동 작업하는 다중 로봇 시스템의 동적 조작도)

  • 심형원
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.10
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    • pp.930-939
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    • 2004
  • In this paper, both dynamic constraints and kinematic constraints are considered for the analysis of manipulability of robotic systems comprised of multiple cooperating arms. Given bounds on the torques of each Joint actuator for every robot, the purpose of this study is to drive the bounds of task-space acceleration of object carried by the system. Bounds on each joint torque, described as a polytope, is transformed to the task-space acceleration through matrices related with robot dynamics, robot kinematics, object dynamics, grasp conditions, and contact conditions. A series of mathematical manipulations including the procedure calculating minimum infinite-norm solution of linear equation is applied to get the reachable acceleration bounds from given actuator dynamic constrains. Several examples including two robot systems as well as three robot system are shown with the assumptions of complete-constraint contact model(or' very soft contact') and insufficient or proper degree of freedom robot.

Kinematic Correction and a Design for Velocity Trajectory to Reduce an Odometer Error of Wheeled-Mobile Robots (구륜 이동 로봇의 주행오차 감소를 위한 기구학적 보정과 속도궤적의 설계)

  • Kim, Jong-Su;Mun, Jong-U;Park, Jong-Guk
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.37 no.3
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    • pp.9-18
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    • 2000
  • This paper presents methods for reducing odometer errors caused by kinematic imperfections in wheeled mobile robots. Wheel diameters and wheelbase are corrected by using encoders without landmarks. And a new velocity trajectory is proposed that compensates for an orientation error due to acceleration-resolution constraints on motor controllers. Based on this velocity trajectory, the wheel velocity of one out of two driven wheels may be changed by the traveled distance of the mobile robot. It is shown that a wheeled mobile robot can't move along a straight line exactly, even if kinematic correction are achieved perfectly, and this phenomenon is attributable to acceleration-resolution constraints on motor controllers. We experiment on a wheeled mobile robot with 2 d.o.f. and discuss the results.

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Tracking Control for Mobile Platform based on Dynamics (동역학을 기반으로 한 모바일플랫폼 궤적제어)

  • Lee, Min-Jung;Park, Jin-Hyun;Jin, Tae-Seok;Cha, Kyung-Hwan;Choi, Young-Kui
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.201-204
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    • 2008
  • The mobile robot is known as a nonlinear system with constraints. The general tracking controller for the mobile platform has been divided into the kinematic and the dynamic controller. The reason of dividing controller is the constraints. We can get some information through some numerical experiments. When the reference linear and angular velocity were given, the stability of mobile robot without the kinematic controller depend on the start point of reference cart. Therefore this paper composed of two controller for solving tracking problem. The main controller is the dynamic controller which used generally such as the PID controller. And this paper adopts the auxiliary controller in order to compensate the difference of initial point between the reference cart and a mobile robot. Finally, the numerical experiment is performed in order to show the validity of our method.

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