• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.204-212
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• 1999

In this paper, the vibrational motion of a flexible beam clamped on a translating base and carrying a moving mass is investigated. The equations of motion which describe the total dynamics of the beam-mass-cart system are derived and the coupled dynamic equations are solved by unconstrained modal analysis. In modal analysis, the exact normal mode solutions corresponding to the eigenfrequencies for the position of the moving mass and the ratios of the mass of the flexible beam, the moving mass and the base cart are used. Proper transformations of the time solutions between the normal modes for a position and those for the next position of the moving mass are also adopted. Numerical simulations are carried out to obtain the open-loop responses of the system in tracking the pre-designed path of the moving mass.

• The Journal of Korean Physical Therapy
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• v.31 no.1
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• pp.13-17
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• 2019

Purpose: This study examined the effects of flexible flatfeet on the accuracy of knee joint motions in closed and open kinetic chain tasks. Methods: Twenty-four healthy participants were recruited for this study. The subjects were divided into two groups using a navicular drop (ND) test: flexible flatfoot group (n=12, male: 6, aged $22.00{\pm}2.22years$) and age-matched control group (n=12, males: 6, aged $22.17{\pm}1.53years$). The accuracy of knee motion was measured quantitatively by tracing through the flexion and extension motion of the knee joints in the closed kinetic chain and the open kinetic chain. Results: There was a significant difference in the accuracy index between the groups in closed kinetic chain task, but there was no significant difference in the open kinetic chain task. In addition, there was a significant difference in the accuracy index between the closed kinetic chain and the open kinetic chain task in the flexible flatfoot group. In addition, a significant negative correlation was observed between the ND and accuracy index in the closed kinematic chain task, but there was no significant relationship between the ND and accuracy index in the open kinematic chain task. Conclusion: Flexible flatfeet can affect the accuracy of the adjacent joints, such as the knee joint in the closed kinematic chain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.233-238
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• 2001

In the design and operation of robot arms with flexible links, the equations of motion are required to exactly model the interaction between rigid motion and elastic motion and to be formulated efficiently. Thus, the flexible link is represented on the basis of the D-H rigid link represented to measure the elastic deformation. The equations of motion of robot arms, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated by using F.E.M to model complex shaped links systematically and by eleminating elastic mode of higher order that does not largely affect option to reduce the number of elastic degree of freedom. Finally presented is the result of simulation to flexible robotic arm whose joints are controlled by direct or PD control.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.592-598
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• 1992

For a high bandwidth, accurate end of arm motion control with good disturbance rejection, the, Momentum Management Approach to Motion control (MMAM) is proposed. The MMAM is a kind of position control technique that uses inertial forces, applied at or near the end of arm to achieve, high bandwidth and accuracy in movement and in the face of force disturbances. To prove the concept of MMAM, the, end point, control of a flexible manipulator is considered. For this purpose, a flexible beam is mounted on the x-y table, and the MMAM actuator is attached on the top of the flexible beam. A mathematical model is developed for the flexible, beam being controlled by the, MMAM actuator and slide base DC motor. A system identification method is applied to estimate some system parameters in the, model which can not be determined because of the complexity of the mechanism. For the end point, control of the. flexible beam, the, optimal linear output feedback control is introduced.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.389-394
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• 2006

Fully flexible cell preserves Hamiltonian in structure, so the symplectic time integrator is applied to the equations of motion. Primarily, generalized leapfrog time integration (GLF) is applicable, but the equations of motion by GLF have some of implicit formulas. The implicit formulas give rise to a complicate calculation for coding and need an iteration process. In this paper, the time integration formulas are obtained for the fully flexible cell molecular dynamics simulation by using the splitting time integration. It separates flexible cell Hamiltonian into terms corresponding to each of Hamiltonian term, so the simple and completely explicit recursion formula was obtained. The explicit formulas are easy to implementation for coding and may be reduced the integration time because they are not need iteration process. We are going to compare the resulting splitting time integration with the implicit generalized leapfrog time integration.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.449-454
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• 2010

The force control of a constrained flexible manipulators has been one of the major research topics. However, a little effort has been devoted for the relation between friction force and elastic deflection of end-effector for a constrained flexible manipulator. So, the aim of this paper is to clarify the friction mechanism of a constrained spatial multi-link flexible manipulator by changing the material and connected method of end-effector. In this study, a concise hybrid position/force control scheme is applied to the control of a flexible manipulator, and the experimental results for the constrained vertical motion and constrained horizontal motion is presented. Finally a comparison between these results are presented to show the reduction of vibration of link and friction force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.279-280
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• 2007

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.251-254
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• 1996

We propose a coordinated motion control algorithm of dual manipulators handling a flexible object. The controller is designed so that it can specify the apparent impedance of the object as well as can control its deformation. The experimental results will illustrate validity of the proposed algorithm.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.17-24
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• 2004

This paper established the dynamic model of a flexible Timoshenko beam with geometrical nonlinearities subject to large overall motions by using the finite element method. The equations of motion are derived by using Hamilton principle based on expressing the kinetic and potential energies of the flexible beam in terms of generalized coordinates. The nonlinear constraint equations are adjoined to the system equations of motion by using Lagrange multipliers.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.559-564
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• 1993

Nonlinear equation of motion of the flexible manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. The resulting equations of motion have a structure which is useful to reduce the number of terms calculated, to check correctness, or to extend the model to high order. A manipulator with a flexible 4 bar link mechanism is a constrained system whose equations are sensitive to numerical integration error. This constrained system is solved using the null space matrix of the constraint Jacobian matrix. Singular value decomposition is a stable algorithm to find the null space matrix.