• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.318-323
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• 2013

For fast and accurate motion of 6-axis articulated robot, more noble motion control strategy is needed. In general, the movement strategy of industrial robots can be divided into two kinds, PTP (Point to Point) and CP (Continuous Path). Recently, industrial robots which should be co-worked with machine tools are increasingly needed for performing various jobs, as well as simple handling or welding. Therefore, in order to cope with high-speed handling of the cooperation of industrial robots with machine tools or other devices, CP should be implemented so as to reduce vibration and noise, as well as decreasing operation time. This paper will realize CP motion (especially joint-linear) blending in 3-dimensional space for a 6-axis articulated (lab-manufactured) robot (called as "RS2") by using LabVIEW$^{(R)}$ (6) programming, based on a parametric interpolation. Another small contribution of this paper is the proposal of motion blending simulation technique based on Recurdyn$^{(R)}$ V7 and Solidworks$^{(R)}$, in order to figure out whether the joint-linear blending motion can generate the stable motion of robot in the sense of velocity magnitude at the end-effector of robot or not. In order to evaluate the performance of joint-linear motion blending, simple PTP (i.e., linear-linear) is also physically implemented on RS2. The implementation results of joint-linear motion blending and PTP are compared in terms of vibration magnitude and travel time by using the vibration testing equipment of Medallion of Zonic$^{(R)}$. It can be confirmed verified that the vibration peak of joint-linear motion blending has been reduced to 1/10, compared to that of PTP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.643-650
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• 2017

The control of flexible joint robot is getting more attentions because its applications are more frequently used for robot systems in these days. This paper proposes a robust impedance controller for the flexible joint robot by using integral sliding mode control and backstepping control. The sliding mode control decouple disturbances completely but requires matching condition for disturbances. The dynamic model of flexible joint robot is divided into motor side and link side and the disturbance of the link side does not satisfy matching condition and cannot be decoupled directly by the actual input in the motor side. To overcome this difficulty, backstepping control technique is used with sliding mode control. The mismatched disturbance in the link side is changed into matched one in the respect to virtual control input which is the state controlled by actual input in the motor side. Integral sliding mode control is used to preserve the impedance control performance and the improved robustness at the same time.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.551-556
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• 1991

This paper deal with the solution of kinematics and inverse kinematics of industrial FANUC robot by the bisection method with IBM PC 386. The inverse kinematics of FANUC robot cannot be solved by the algebraical method, because arm matrix T$_{6}$ is very complex and 6-joint angles are associated with the position and the approach of end-effector. Instead we found other 5-joint angle by an algebraical method after finding .theta.$_{4}$ value by a bisection method.d.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.235-238
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• 1989

Generally, Industrial robots are often controlled using joint processors and treating each joint as an independent servo loop. This paper presents a system architecture for robot control designed for real-time control of motion and sensory processing utilizing general-purpose Personal Computer. And for easily use and system expendability, robot language is implemented with C-language as base language. Through this system user can easily update robot language by design of his own language primitives. This system also don't require another development tool and can be used as advanced algorithm simulator in robotics laboratories.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.953-958
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• 1992

This paper deals with the solution of inverse kinematics of the industrial FANUC robot with IBM PC386. The inverse kinematics of FANUC robot cannot be solved by the algebraical method, because arm matirix T$_{6}$ is very complex and 6-joint angles are associated with the position and the approach of end-effector. Instead we fuund otehr 5-joint angle by and algebraical method after finding .THETA.$_{1}$ value by a numerical method.d.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.943-951
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• 2003

A strategy for fault-tolerant gaits of autonomous legged robots is proposed. A legged robot is considered to be fault tolerant with respect to a given failure if it is guaranteed to be capable of walking maintaining its static stability after the occurrence of the failure. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue static walking. An algorithm for generating fault-tolerant gaits is described and, especially, periodic gaits are presented for forward walking of a hexapod robot with a locked joint failure. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The transition procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1418-1423
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• 2004

A legged robot is friendly to human because it is resemble to human. And the robot can obtain support points freely because it has high degree of freedom for several joint as compared with a wheeled robot. Also the robot can create the relative position at desired position between support position and robot. The joint of robot cu used as manipulator. On the contrary the mechanism of robot is complicated to have many joint and moving speed is lower than wheeled robot. Also the legged robot is needed a special control not to fall on the ground because the robot is easy to vibrate when it is moving. The 4 leg structure is the minimum leg numbers not to fall and to realize safety gait continuously. A trot gait is investigated through experiments using a quadruped walking robot named TITAN-VIII.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.144-153
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• 1997

The determination of the direct kinematics of the parallel mechanism is a difficult problem but has to be solved for any practical use. This paper presents the efficient formulation of the direct kinematics for double parallel robot arm. The robot arm consists of two parallel mechanism, which generate positional and orientational motions, respectively. These motions are decoupled by a passive central axis which is composed of four revolute joints and one prismatic joint. For a set of given lengths of linear actuators, the direct kinematics will find the joint displacements of th central axis from geometric constraints in each parallel mechanism. Then the joint displacements will be converted into the position and the orientation of the end effector of the robot arm. The proposed formulation is decoupled and compacted so that it will be implemented as a real-time direct kinematics. With the proposed formulation, we analyze the motion of the double parallel robot and show its characteristics. Specially, we investigate the workspace in terms of positional space as well as orientational space.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.100-106
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• 2013

This paper deals with the design method for a small waterproof 4-axis robot arm. An extensive analysis was performed on the torque applied to the robot joint as a result of the payload, as well as the design of the joint actuator capacity. In addition, a study was undertaken on the design of a waterproof joint actuator that works at depths greater than 10 m and the wiring design for a small waterproof connector to avoid obstructing the robot motion. Finally, a finite element method simulation was carried out to analyze the strength of the designed robot arm link, and its stability was verified through a simulation test.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.267-274
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• 2010

In this paper, the structure of a gravity compensator was studied, and the 6-axis robot manipulator which is newly developed by applying the gravity compensator is presented to improve the torque performance of the robot joint. The kinematics analysis on the robot was presented. Also, a simulation of the performance of the joint actuator of robot adopting the gravity compensator was presented by applying various springs. According to the simulation results, it was validated that the payload effect on the robot joint actuator adopting the gravity compensator is reduced in proportion to the spring intensity of the gravity compensator.