• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.389-396
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• 2016

The sealing robot must be able to calculate the slope of a contact surface for complete adherence of the sealing on different concrete shapes. After the slope is obtained, the robot will track on the surface of the concrete, but this process contains an error in the actual purpose of the force command. The reason this a phenomenon occurs, the non-linearity of the contact surface and the end-effector, is due to parasitic coupling. Errors like make it difficult to measure accurately the respective factors. Therefore, it is regarded as a disturbance that occurs when it follows the work surface it. In this paper, we selected the friction coefficient of the surface as a control factor and designed a compensator to reduce effects of disturbance. Finally, in view of the non-linearity of the end-effector of a robot to contact surfaces directly, we propose a robust force tracking controller in the finite range for managing disturbances that occur during the sealing.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.1-6
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• 2008

In industrial fields, human works are being replaced by robots. However, as the use of robots is limited in the process industry where they are operated fixedly, humanoid robots with wide applications need to be developed. Currently a great deal of research is being conducted on humanoid robots with the object of replacing humans in the workplace. However, because of the lack of relevant hardware and difficulty in mechanical parts, only very simple and limited progress is being made. In an effort to overcome these limitations, the purpose of the present study is to develop a kinematical mechanism and a controller. To this end, master arms with 3 degrees-of-freedom for the shoulders and the arms were composed which were able to reproduce human-like motions by simulating the characteristics of joint variables and the trajectory of the end-effector.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.345-348
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• 1997

In this paper, a motion control algorithm is developed using a fuzzy control and the optimization of performance function, which makes a robot arm avoid an unexpected obstacle when the end-effector of the robot arm is moving to the goal position. During the motion, if there exists no obstacle, the end-effecter of the robot arm moves along the pre-defined path. But if there exists an obstacle and close to the robot arm, the fuzzy motion controller is activated to adjust the path of the end-effector of the robot arm. Then, the robot arm takes the optimal posture for collision avoidance with the obstacle. To show the feasibility of the developed algorithm, numerical simulations are carried out with changing both the positions and sizes of obstacles. It was concluded that the proposed algorithm gives a good performance for obstacle avoidance.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.896-901
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• 1990

A simulation analysis is presented for the position control of a single-link flexible manipulator whose end-effector is subjected to an impulsive force. Arm is rotated by a d.c. servomotor at the shoulder so that the end point stays precisely at its initial position even if the end effector is thumped with the impulsive loading. A gap sensor is used to measure the tip displacement. The control torque based on the PD control law is applied to the motor through the driver circuit. The control strategy is tested by means of computer simulation for the one-link flexible-arm prototype in the authers' laboratory at Tohoku Univ.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.32-39
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• 2022

Since the mobile platform and the manipulator mounted on it move at the same time in a mobile manipulator, the risk of mutual collision increases. Most of the studies on collision avoidance of mobile manipulators cannot be applied to differential drive type mobile platforms or the end-effector tends to deviate from the desired trajectory for collision avoidance. In this study, a collision avoidance algorithm based on null space projection (CANS) that solves these two problems is proposed. To this end, a modified repulsive force that overcomes the non-holonomic constraints of a mobile platform is generated by adding a virtual repulsive force in the direction of its instantaneous velocity. And by converting this repulsive force into a repulsive velocity and applying it to the null space, the end-effector of the robot avoids a collision while moving along its original trajectory. The proposed CANS algorithm showed excellent performance through self-collision avoidance tests and door opening tests.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.2
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• pp.126-139
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• 2022

The need for synthetic automation is increasing in preparation for a gradual decrease in laboratory research manpower due to low birth rate and aging. In this study, the existing laboratory synthesis method is analyzed based on the systems engineering technique. Then, it led to the derivation of the system requirements for a fixed-based robot manipulator capable of recognition, decision and control. The robot is equipped with replaceable modular end-effectors and designed depending on the purpose and process of the synthesis. The robot with an end-effector was implemented as PoC(Proof-of-Concept), and the functions for pipetting automation was verified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.7-12
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• 2019

Generally, end effectors for automatic robots can use ceramics such as alumina(Al₂O₃) and silicon carbide(SiC). In this study, black alumina was developed and used in the semiconductor field through powder molding press forming. The black alumina can be mass produced.Alumina and black alumina were ground using a plane grinder to apply to the end effector of an automatic robot. The optimal cutting conditionswere found by analyzing the surface roughness(Ra) of black alumina through grinding. The alumina surface roughness is the feed rate was about 0.72 mm/sec, and the number of revolutions was best at 0.4879 ㎛ at 1700 rpm. In addition, the black alumina surface roughness shows a precision of less than 0.2 ㎛ in most cutting conditions. The feed rate was about 0.72 mm/sec, and the number of revolutions was best at 0.1361 ㎛ at 1900 rpm. The surface roughness of black alumina was better than that of alumina by about 0.35 to 0.47 ㎛.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.243-246
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• 2017

In this study, flexible fixtures and end effectors are conceptually designed for the holding of thin-walled carbon-fiber reinforced-plastic (CFRP) workpieces in machining processes. Firstly, the fixture scenarios and system requirements for the conceptual designs of flexible-fixture and core units are proposed, including the propounding of the workpiece-holding mechanism and the core-unit requirements. A ball-joint pneumatic system is determined as a locking mechanism of the flexible-fixture system for the machining of thin-walled components. Secondly, conceptual designs of the core units are suggested with the driven requirements from the fixture scenarios. A self-tilting mechanism and an end-effector return mechanism are also proposed. Finally, the prototypes of the core units are manufactured, and the workpiece-holding capacity of each prototype is measured.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.46-51
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• 2004

This paper presents an adaptive control method based on parameter linearization for incompletely restrained wire-suspended mechanisms. The main purpose of this control method is utilizing it in a walking assist service robot for elderly people. This method is computationally simple and requires neither end-effector acceleration feedback nor inversion of estimated inertia matrix. In the proposed adaptive control law, mass, moment of inertia and external force and torque on the end-effector are considered as components of parameter adaptation vector. Nonlinear simulation for walking an elderly shows the effectiveness of the parameter adaptation law.