• Journal of the Institute of Convergence Signal Processing
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• v.15 no.3
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• pp.104-111
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• 2014

In this paper, we deal with robotic automation for assembling car brake modules. A car brake module is comprises of a torque member, two brake pads, and two pad liners. In the assembly process, brake pads and pad liners are needed to be inserted in a torque member. If we use a typical robotic hand for the assembly, task time takes too long. So, we propose two methods. The first method is to use an end effector that has five grippers capable of gripping five assembly parts. In the first method we attached the implemented end effector to a conventional 6 degrees of freedom industrial manipulator and performed the bake module assembly task. Experimental results show that the task time is remarkably reduced. The brake module assembly task needs the robot to change its orientation frequently, so, in the second method, we added one degree of freedom to the end effector that is used in the first method. By attaching it to a conventional 6 degrees of freedom industrial manipulator, we composed a 7 degrees of freedom redundant manipulator. A redundant manipulator has the advantage of flexible manipulation so the robot can change its orientation easily and can perform assembly task very fast. Experimental results show that the second method dramatically reduce whole task time for brake module assembly.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.27-33
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• 2011

Control and trajectory generation of a 7 DOF anthropomorphic robot arm suffer from computational complexity and singularity problem because of numerical inverse kinematics. To deal with such problems, analytical methods for a redundant robot arm have been researched to enhance the performance of inverse kinematics. In this research, we propose an analytical inverse kinematics algorithm for a 7 DOF anthropomorphic robot arm. Using this algorithm, it is possible to generate a trajectory passing through the singular points and intuitively move the elbow without regard to the end-effector pose. Performance of the proposed algorithm was verified by various simulations. It is shown that the trajectory planning using this algorithm provides correct results near the singular points and can utilize redundancy intuitively.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.133-136
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• 1996

The nozzle dam task is essentially needed to maintain and repair nuclear power plants. For this task, an 8-dof redundant robot is studied with a local path-planning method[l] which is effective to find the optimal joint path in the constrained environment. In this paper, the method[l] is improved practically with the weight matrix and efficient algorithm to find working set. The effectiveness of the proposed method is demonstrated by simulation and animation.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.124-126
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• 1989

Inverse kinematic problem is a crucial point for robot manipulator control. In this paper, to implement the Jacobian control technique we used the Hopfield(Tank)'s neural network. The states of neurons represent joint veocities, and the connection weights are determined from the current value of the Jacobian matrix. The network energy function is constructed so that its minimum corresponds to the minimum least square error. At each sampling time, connection weights and neuron states are updated according to current joint position. Inverse kinematic solution to the planar redundant manipulator is solved by computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.1002-1012
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• 2003

An algorithm is suggested for collision avoidance of two-arm robot manipulator using redundancy. End-effectors of each redundant arm should move along each prescribed straight path to complete the given task, while avoiding collision with each other. Self-motion, considered as motion of each axis not to change the position and orientation of end-effector, is utilized in order to solve this problem. At each sampling time, self-motion is executed with the view to making farther between the links of each arm. Simulation results for two-arm robot manipulator, which has 9-d.o.f. respectively, are illustrated to show the performance of the algorithm.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.42-54
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• 2017

Using an inverse of the geometric Jacobian matrix is one of the most popular ways to control robot manipulators, because the Jacobian matrix contains the relationship between joint space velocities and operational space velocities. However, the control algorithm based on Jacobian matrix has algorithmic singularities: The robot manipulator becomes unstable when the Jacobian matrix loses rank. To solve this problem, various methods such as damped and filtered inverse have been proposed, but comparative studies to evaluate the performance of these algorithms are insufficient. Thus, this paper deals with a comparative analysis of six representative singularity avoidance algorithms: Damped Pseudo Inverse, Error Damped Pseudo Inverse, Scaled Jacobian Transpose, Selectively Damped Inverse, Filtered Inverse, and Task Transition Method. Especially, these algorithms are verified through computer simulations with a virtual model of a humanoid robot, THORMANG, in order to evaluate tracking error, computational time, and multiple task performance. With the experimental results, this paper contains a deep discussion about the effectiveness and limitations of each algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.642-648
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• 2008

A lot of researches on the redundant manipulators have been focused mainly on the minimization of joint torques. However, it is well-known that the most dynamic control algorithms using local joint torque minimization cause huge torques which can not be implemented by practical motor drivers. A new control algorithm which reduces considerably such a huge-required-torque problem is proposed in this paper. It adapts fuzzy logic and genetic algorithm to the conventional local joint torque minimization algorithm. The proposed algorithm is applied to a 3-DOF redundant planar robot. Simulation results show that the proposed algorithm works well.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1944-1948
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• 2005

This paper presents how it is effective to use many features for improving the speed and the accuracy of the visual servo systems. Some rank conditions which relate the image Jacobian and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm Robot manipulator made in Samsung Electronic Co. Ltd

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.103-106
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• 2001

A new control method for a redundant manipulator is developed using a local optimal torque and null space joint velocity. By solving the dynamic control equations of the system, the local optimal torque is obtained. If only the local optimal torque is used for controlling the robot there is a possibility that the system is unstable. To eliminate the characteristics of instability during the movements, the control law with a null space concept is used. The new method is applied to the 3-DOF planar manipulator. The simulation results show the effectiveness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.37-40
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• 1988

It is well-known that the redundancy can be exploited to avoid the singular regions of the redundant manipulator by increasing the manipulability. The method, however, requires exprecessive energy and gives rather large tracking errors since the manipulability is increased repidly so that the manipulator avoid the singular region quickly. In this paper, a new method is proposed in which the increasing speed of the manipulability is confined to a certain bound. Therefore, in the proposed method, the movement energy and the tracking errors are reduced. The computer simulation studies are performed to show the validity of the method.