• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.396-399
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• 1995

This paper presents a new formulation of the kinematics of closed-chain mechanisms and its applications to obtaining the kinematic solutions and analyzing the singularities. Closed-chain mechanisms under consideration may have the redundancy in the number of joints. A closed-chain mechanism can be treated as the parallel connection of two open-chains with respect to a point of interest. The kinematics of a closed-chain mechanism is then obtained by imposing the kinematic constraints of the closed-chain on the kinematics of the two open-chains. First, we formulate the kinematics of a closed-chain mechanism using the kinematic constraint between the controllable active joints and the rest of joints, instead of the kinematic constraint between the two open-chains. The kinematic formulation presented in this paper is valid for closed-chain mechanisms with and without the redundancy. Next, based on the derived kinematics of a closed-chain mechanism, we provide the kinematic solutions which are more physically meaningful and less sensitive to numerical instability, and also suggest an effective way to analyze the singularities. Finally, the computational cost associated with the kinematic formulation is analyzed.

• Journal of information and communication convergence engineering
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• v.19 no.2
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• pp.84-92
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• 2021

The research on waste power batteries in China in the past ten years reveals that the power battery recycling industry is enormous but marred with several challenges. A study of China's current power battery closed-loop supply chain revealed some issues in the power battery recycling industry, such as imperfect supply chain, small recycling scale, asymmetric information, and imperfect profit distribution mechanism. This paper uses the theory of corporate social responsibility and consumer choice to propose a closed-loop network of power batteries based on block chain technology and analyzes the existing closed-loop supply chain of power batteries. Consequently, this study provides a new idea for developing the power battery closed-loop supply chain by proposing the closed-loop network of power batteries based on blockchain technology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.570-571
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• 2021

The research on waste power batteries in China in the past ten years reveals that the power battery recycling industry is enormous but marred with several challenges. A study of China's current power battery closed-loop supply chain revealed some issues in the power battery recycling industry, such as imperfect supply chain, small recycling scale, asymmetric information, and imperfect profit distribution mechanism. This paper uses the theory of corporate social responsibility and consumer choice to propose a closed-loop network of power batteries based on block chain technology and analyzes the existing closed-loop supply chain of power batteries. Consequently, this study provides a new idea for developing the power battery closed-loop supply chain by proposing the closed-loop network of power batteries based on blockchain technology

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.72-81
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• 2005

A new spherical-type 3-degree-of-freedom parallel mechanism consisting of a two degree-of-freedom parallel module and a serial module is proposed. Two alternative designs for the serial sub-chain are suggested and compared. The first design employs RU joint arrangement for the serial sub chain structure. The second design incorporates a gear chain to drive the distal revolute joint of the serial sub-chain from the base platform of the mechanism. This modification significantly improves kinematic characteristics of the mechanism within its workspace. Firstly, the closed-form solutions of both the forward and the reverse position analysis are derived. Secondly, the first-order kinematic model with respect to three inputs which are located at the base is derived. Thirdly, it is confirmed through simulation that the modified mechanism has much more improved isotropic characteristic throughout the workspace of the mechanism. Lastly, the proposed mechanism is implemented to verify the results from this analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.2
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• pp.238-245
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• 2003

To overcome the weakness in the load capacity of conventional robot manipulators actuated by motors with the speed reducer such as the harmonic driver, we proposed a new closed-chain type of the robot actuator which is composed of the four-bar-link mechanism driven by the ball screw. The robot manipulator is revolute-jointed and composed of four axes. The base axis is actuated by the lineal actuator such as the ball screw, and the others are actuated by the proposed actuator. We analyzed the mechanism of the actuators of the robot joints, and developed the dynamics model. The dynamics are expressed in the joint coordinates and then they are mapped into the sliding coordinates of the ball screw. We performed fundamental tests on the structure of the robot.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.846-855
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• 1994

An effective stiffness, analogous to that of a wound spring, can be created by antagonistic redundant actuation of general closed-chain mechanisms. The qualitative and quantitative characteristics of the effective stiffness are investigated through a Four-bar mechanism, and a load distribution method is introduced which simultaneously guarantees the required system motion and the effective stiffness of the Four-bar mechanism. Furthermore, a simulation is performed to understand the inter-relationship among the effective stiffness, the Four-bar geometry, and the actuation effort. Based on this analysis, the Four-bar synthesis problem for effective stiffness generation is discussed.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.209-214
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• 2003

We developed a new type of human-sized BWR (biped walking robot), named KUBIR1 which is driven by the closed-chain type of actuator. A new type of the closed-chain actuator for the robot is developed, which is composed of the four-bar-link mechanism driven by the ball screw which has high strength and high gear ratio. Each leg of the robot is composed of 6 D.O.F joints. For front walking, three pitch joints and one roll joint at the ankle. In addition to this, one yaw joint for direction change, and another roll joint for balancing the body are attached. Also, the robot has two D.O.F joints of each hand and three D.O.F. for eye motion. There are three actuating motors for stereo cameras for eyes. In all, a 18 degree-of-freedom robot was developed. KUBIR1 was designed to walk autonomously by adapting small 90W DC motors as the robot actuators and batteries and controllers are on-boarded. The whole weight for Kubir1 is over 90Kg, and height is 167Cm. In the paper, the performance test of KUBIR1 will be shown.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.118-123
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• 2000

Most quadruped walking robots under current research are individually controlling every joint ic make them step or walk according to an integrated strategy. Such methods are characterized by at least one pair of an actuator and a sensor installed per each 'oint so that the robots weigh execssively and move inefficiently in terms of energy expenditure. In addition, the task of controlling all the joints simultaneously is quite complex and prone to destabilize the robot motion. These respects keep the existing walking robots away from realistic applications such as transportation even if they have potentially, outstanding adaptability to swamps or uneven terrains as opposed to wheeled vehicles. So, this paper presents a new conceptual quadruped robot developed to walk and steer only with a minimal number of actuators owing to a closed-chain mechanism. To prove its actual performance including the adaptability to various types of terrains. experiments are done with the mammal-type prototype. And. it is also shown that the same concept can be easily extended to carry out different gait forms. for instance, that of spiders only with minor modifications.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.118-127
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• 2005

A spatial 3 degrees-of-freedom mechanism employing Stewart Platform structure is proposed: the mechanism maintains the 3- RRPS structure of Stewart Platform but has an additional passive PRR serial sub-chain at the center area of the mechanism in order to constrain the output motion of the mechanism within the output motion space of the added PRR serial subchain. The forward and reverse position analyses of the mechanism are performed. Then the mechanism having both the forward and the reverse closed-form solutions is suggested and its closed form solutions are derived. It is confirmed, through the kinematic analysis of those two proposed mechanisms via kinematic isotropic index, that both the proposed mechanisms have fairly good kinematic characteristics compared to the existing spatial 3-DOF mechanisms in literature.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.103-111
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• 2003

The Denavit-Hartenberg symbolic notation provides the framework for the convenient and systematic method for the robot manipulator kinematics, but is limited its use to the lower pair mechanism or to the single loop mechanisms. The Sheth-Uicker notation is its revised and generalized version to be extended fur the entire domain of the link mechanism including the higher pairs. This paper proposes the method that uses the Sheth-Uicker notation fur the robot kinematics modeling. It uses the instantly coincident coordinate system and the closed loop chain fur the coordinate transformation. It enables us to model the velocity kinematics of the robot that has the complex structures such as the ternary links and the wheels in a systematic and rational way. As an implementation of the proposed method, the Jacobian matrices were obtained for not only the robot with two legs and a torso, but a manipulator on a mobile platform.