• Journal of the Korean Society for Precision Engineering
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• v.25 no.10
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• pp.92-98
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• 2008

This paper is concerned with the designing and making power standing wheelchair. This wheelchair is studied based on the mechanical and electrical engineering concepts and theories. The mechanical theories are composed of statics and dynamics knowledges that are related with moving and standing position. Basically the static and dynamic stability is the most important element in designing and making the real size model. The linear actuator is used in the standing mechanism and the joystick controlled by hand is attached on the arm rest. The real size model is made and also investigated through the design specifications by test drive. Finally, this paper proves the possibility of commerical production of power standing wheelchair.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.93-98
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• 2005

The purposes of this paper are the review and derivation of design characteristics for the new construction of the practical flexible manufacturing system. The basic ideas to analyze the manufacturing system which is the automatically operated are dependant on the various manufacturing procedures in factory. The practical flexible manufacturing systems have various mechanical subsystems appropriated fur the final manufacturing products. Therefore the systems have the various kinds of hardwares as well as softwares. We study the software for the practical flexible manufacturing system designed and developed in the Halla University with the related company. Specially the design concepts and using specifications of all subsystems which are composed of mechanical and electronic movements of the product are analyzed and introduced in this dissertation.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.126-132
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• 2002

Robot manipulator has highly nonlinear dynamics. Therefore the control of multi-link robot arms is a challenging and difficult problem. In this paper an independent joint adaptive fuzzy sliding mode scheme is developed leer control of robot manipulators. The proposed scheme does not require an accurate manipulator dynamic model, yet it guarantees asymptotic trajectory tracking despite gross robot parameter variations. Numerical simulation for independent joint control of a 3-axis PUMA arm will also be included.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.148-161
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• 1998

We investigate a design methodology for master arm which is employed in remote-site control. Though counter-balancing has been employed for the purpose of lessening the actuator loads, it results in the increase of dynamic load at the task position. Therefore, there exists a trade-off between counter-balancing and dynamic performance. The concept of a composite index is introduced to simultaneously consider those two effects in the design of master arms. Several alternative designs of master arms are suggested.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1190-1193
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque, so that the estimation of damping property from the isokinetic movement is difficult.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.133-140
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• 1993

In this paper, we prpose a method for tracking optimally a spatial trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint euqations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation result of a flexible planar manipulator is presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1133-1137
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• 1995

This paper presents a numerical method of the global search for an optimal geometric path for a manipulator arm amid obstacles. Finite term quintic B-splines are used to describe an arbitrary point-to-point manipulator motion with fixed moving time. The coefficients of the splines span a linear vector space, a point in which uniquely represents the manipulator motion. All feasible geometric paths are searched by adjusting the seed points of the obstacle models in the penetration growth distances. In the numerical implementation using nonlinear programming, the globally optimal geometric path is obtained for a spatial 3-link(3-revolute joints) manipulator amid several hexahedral obstacles without simplifying any dynamic or geometric models.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.164-170
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• 2003

To ensure the reliability of DVDR-P and DVD-ROM, it is imperative to remedy the unrecoverable creep deformation and/or relaxation of the holding force of an optical disc holder. To predict the deformation of an optical disc holder, a deformation analysis of an 80 mm optical disc holder considering the creep characteristics of 3 plastic materials has been conducted. Subsequently, the results by this Finite Element Analysis (FEA) are experimentally verified. A disc holder inserted in a cartridge case is kept in a chamber of $60^{\circ}C$ with 90 % humidity for 24 hours. The arm span and the holding force of the disc holder are measured after being left for another 24 successive hours at a room temperature and under normal humidity. The predicted results by FEA are in good agreement with experimentally measured values.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.123-129
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• 1996

Computed torque method has been used for precise trajectory control of the robotic system that involves nonlinear dynamics. It is hard to know exact values of robot system parameters, and the robot arm receives umpredictable interference from the working environment. These disturbances, especially in a direct drive robot, are directly transmitted to actuating motor without reduction. Modelling error and distrubance can cause significant errors in a trajectory tracking problem. In this paper, we propose a new controller that $H_{\infty}$controller is conbined to robot system linearized by computed torque. Simula- tions are made for comparing the performance of the proposed controller with that of a nonlinear $H_{\infty}$ controller proposed by Chen and also computed torque method.hod.