• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.964-970
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• 2014

In this study we have developed an anthropomorphic robot hand and arm by using tendon-tubes which can be used for people's everyday life as a robot's dynamic power transmission device. Most previous robot hands or arms had critical problem on dynamic optimization due to heavy weight of power transmission parts which placed on robot's finger area or arm area. In order to resolve this problem we designed light-weighted robot hand and arm by using tendon-tubes which were consisted of many articulations and links just like human's hand and arm. The most prominent property of this robot hand and arm is reduction of the weight of robot's power transmission part. Reduction of weight of robot's power transmission parts will allow us to develop energy saving and past moving robot hands and arms which can be used for artificial arms. As a first step for real development in this study we showed structural design and demonstration of simulation of possibility of a robot hand and arm by tendon-tube. In the future research we are planning to verify practicality of the robot hand and arm by applying sensing and controlling method to a specimen.

• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.8
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• pp.977-989
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• 1999

The purpose of this study is to analyze how the human body having more muscles than its degree-of-freedom modulates an effective stiffness using redundant actuation, and to apply this concept to the design and control of advanced machines which requires adaptable spring. To investigate the adaptable stiffness phenomenon due to redundant actuation in the human body, this paper derives a general stiffness model of the Human body. In particular, for a planar 1 DOF human arm model, a planar 2 DOF human arm model, a spherical 3 DOF shoulder model, a 4 DOF human arm model, and a 7 DOF human arm model, the required nonlinear geometry ad the number of required actuator for successful modulation of the effective stiffness are analyzed along with a load distribution method for modulation of the required stiffness of such systems. Secondly, the concept of motion frequency modulation is introduced to show the usefulness of adaptive stiffness modulation. The motion frequency modulation represents a control of stiffness and / or inertia properties of systems. To show the effectiveness of the proposed algorithm, simulations are performed for 2 DOF anthropomorphic robot.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.656-664
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• 2016

While anthropomorphic robots are gaining interest, dual-arm robots are widely used in the industrial environment. Many methods exist in order to implement bimanual tasks by dual-arm robot. However, kinesthetic teaching is used in this paper. This paper suggests three different kinesthetic teaching methods that can implement most of the human task by the robot. The three kinesthetic teaching methods are joint level, task level, and contact level teaching. The task introduced in this paper is box packing, which is a popular and complex task in industrial environment. The task is programmed into the dual-arm robot by utilizing the suggested kinesthetic teaching method, and this paper claims that most tasks can be implemented by using the suggesting kinesthetic teaching methods.

• The Journal of Korea Robotics Society
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• v.10 no.1
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• pp.42-51
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• 2015

Peg-in-hole assembly is the most representative task for a robot to perform under contact conditions. Various strategies for accomplishing the peg-in-hole task with a robot exist, but the existing strategies are not sufficiently practical to be used for various assembly tasks in a human environment because they require additional sensors or exclusive tools. In this paper, the peg-in-hole assembly experiment is performed with anthropomorphic hand arm robot without extra sensors or devices using "intuitive peg-in-hole strategy". From this work, the probability of applying the peg-in-hole strategy to a common assembly task is verified.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.181-192
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• 1995

In this study, we introduce new types of planar 2 degree-of-freedom robot modules resembling the musculoskeletal structure of the human arm with actuation redundancy. First, for the given actuator sizes the performance analysis for the manipulator with redundant actuation and without redundant actuation is performed with respect to maximum load handling capacity, maximum hand velocity, and maximum hand acceleration. Secondly an algorithm which decides optimal actuator sizes for the given operational performances is introduced, and the optimal actuator sizes for a robot module with four redundant actuation are obtained. The algorithms employed in this paper will be useful to analyze the robot performances and to determine the actuator sizes for general robot manipulators.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.199-204
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• 1999

The robot inverse calibration method using a neural networks is proposed in this paper. A high-order networks has been used in this study. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the selected compliance automatic robot arm type direct drive robot and anthropomorphic robot are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from ${\pm}$0.15$^{\circ}$to ${\pm}$0.12$^{\circ}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5219-5226
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• 2011

A specialized anthropomorphic robot manipulator which can be attached to the housemaid robot McBot II, is developed In this paper. This built-in type manipulator consists of both arms with 3 DOF (Degree of Freedom) each and both hands with 3 DOF each. The robotic arm is optimally designed to satisfy both the minimum mechanical size and the maximum workspace. Minimum mass and length are required for the built-in cooperated-arms system. But that makes the workspace so small. This paper proposes optimal design method to overcome the problem by using neck joint to move the arms horizontally forward/backward and waist joint to move them vertically up/down. The robotic hand, which has two fingers and a thumb, is also optimally designed in task-based concept. Finally, the good performance of the developed manipulator is confirmed through live test of tasks.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.421-424
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• 1987

Recently, the problem associated with the achievement of desired trajectories for non-linear robotic manipulatory systems are researched. The control system which is designed for this robot manipulator, poses a number of severe problem. The methods proposed to deal with the problem fall loosely into three main classes : "direct" "adaptive", "anthropomorphic". Besides there is an approach which is described based upon the application of optimal control theory. In this paper, using the optimal theory, we choose error-coordinate, between the desired trajectories and the practical as the state values, and determine the control law U which minimize a corresponding performance criterion. Let's consider the robotic arm proposed by Freund and set up the deviations of it's trajectory as a measure of performance. To find the optimal control law $U^*$ and the next state value which need to obtain $U^*$ here, we should introduced the conjugate gradient algorithm and the Runge Kutta method.