• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.87-92
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• 2001

An error analysis is very important for a precision machine to estimate its performances. This study proposes a new parallel device, cubic parallel manipulator. Errors of the proposed cubic parallel manipulator include upper and down universal joint errors, due to the directional changes in the forces in the links, and actuation errors. An error analysis is presented based on an error model formed through the relation between the universal joint errors of the cubic parallel manipulator and the end effector accuracy. The analysis shows that the method can be used in predicting the accuracy of other cubic parallel devices.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.545-549
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• 1993

This paper presents the method of calibrating and compensating for the kinematic errors in robot manipulators. A calibration model is developed to represent any geometric errors in the manipulator's structure. A calibration jig is used to find the values of these kinematic errors in the end-effector's position and a calibration algormined for a SSR-6 robot manipulator developed by Samsung Heavy Industry, Daeduk R & D Center. Through this experiment the maximun kinematic error is reduced from 10mm to 0.4mm

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.703-709
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• 2000

This paper proposes a compliance control strategy for the robot manipulators accidentally interact-ing with an unknown environment. In this proposed method each in the diagonal stiffness matrix corre-sponding to the task coordinate in a Cartesian space is adaptively adjusted during contact along the corresponding axis based on the contact force with its environment. This method can be used for both unconstrained and constrained motions without any switching mechanism which often causes undesirable instability and/or vibrational motion of the end-effector. The experimental results show the effectiveness of the proposed method by employing a two link direct drive manipulator interacting with an unknown environment.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.1-7
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• 2003

In this paper, we discuss the control scheme on active compliance control of flexible manipulators. The active compliance control scheme is extended from the scheme for rigid manipulators. To illustrate the validity of the proposed control scheme, we show experimental results for the case when the end-effector is not moving and when it is moving while applying force. Although flexible manipulators show some problems of stability yet it is clear from these results that flexible manipulators are more effective to reduce damage of environment because of link flexibility than rigid ones.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.04a
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• pp.390-394
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• 1994

In many cases, tasks are unpredictable and therefore not doable by special-purpose or pro-programble robots. So master/slave type robot hands which combine human perceptions with conventional robot hands are required as robot end effector. These also can be applied to hazardous worksites such as outer space, deep sea and nuclear power plant. In this study, master/slave type robot fingers with 3 joints each are designed and constructed. To control force accurately, TDT(tension difference type) torque sensors are constructed and attached toeachjoints of slave finger and new force reflecting control algorithm is suggested. Finally, experimental results show that the new control algorithm can be successfully applied.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.753-759
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• 2011

In this paper, we propose the direction of development for EOD robot. We collected and analyzed the opinions of EOD teams. In order to verify the opinions, we conducted QFD(Quality Function Deployment) analysis. Based on the QFD analysis, we work out the priority of EOD robot development. And we establish the goal of development(target system) and suggest the development direction of EOD robot on each issue.

• Journal of Mechanical Science and Technology
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• v.18 no.11
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• pp.1949-1960
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• 2004

This paper presents a robot system developed for medical purpose. A 6-degree-of-freedom robot was introduced for physical exercise and rehabilitation. This system was proposed for stroke patients or patients who cannot use one of their arms or legs. The robot system exercises the hemiplegic part based on the motion of normal part of a patient. Kinematic studies on the human body and robot were applied to develop the robotic rehabilitation exercise system. A clamp which acts as an end effector of the robot to hold a patient was designed and applied to the robot to guarantee the safety of patients. The proposed robotic rehabilitation system was verified by simulations and experiments on arm (elbow and shoulder) motion. Patients are expected to be able to exercise various motions by themselves with the proposed robotic rehabilitation system.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.66-72
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• 1999

Robot calibration is very important to improve the accuracy of robot manipulators. However, the calibration procedure is very time consuming and laborious work for users. In this paper, we propose a method of relative error compensation to make the calibration procedure easier. The method is completed by a Pi-Sigma network architecture which has sufficient capability to approximate the relative relationship between the accuracy compensations and robot configurations while maintaining an efficient network learning ability. By experiment of 4-DOF SCARA robot, KIRO-3, it is shown that both the error of joint angles and the positioning error of end effector are drop to 15$\%$. These results are similar to those of other calibration methods, but the number of measurement is remarkably decreased by the suggested compensation method.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1119-1127
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• 2012

In this paper, we present an inverse kinematics of a 7-dof Anthropomorphic robot arm using conformal geometric algebra. The inverse kinematics of a 7-dof Anthropomorphic robot arm using CGA can be computed in an easy way. The geometrically intuitive operations of CGA make it easy to compute the joint angles of a 7-dof Anthropomorphic robot arm which need to be set in order for the robot to reach its goal or the positions of a redundant robot arm's end-effector. In order to choose the best solution of the elbow position at an inverse kinematics, optimization techniques have been proposed to minimize an objective function while satisfying the euler-lagrange equation.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.350-356
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• 2020

Workers have been replaced by mobile manipulators for factory automation in recent years. One of the typical tasks for automation is that a mobile manipulator moves to a target location and picks and places an object on the worktable. However, due to the pose estimation error of the mobile platform, the robot cannot reach the exact target position, which prevents the manipulator from being able to accurately pick and place the object on the worktable. In this study, we developed an automatic alignment system using a low-cost camera mounted on the end-effector of a collaborative robot. Camera calibration and pose estimation methods were also proposed for the automatic alignment system. This algorithm uses a markerboard composed of markers to calibrate the camera and then precisely estimate the camera pose. Experimental results demonstrate that the mobile manipulator can perform successful pick and place tasks on various conditions.