• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1581-1584
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• 1997

This paper poropsed an efficient optimization technuque to resolve redundancy and a trajectory planning for a high precision control using proposed optimization technique. The proposed techniqus is the joint disturbance torque optimizatioin considering redundancy in the joing servo control. Joint disturbance torque is not unknown it is described dynamic equation ignored friction and viscosity. The proposed technique is used the dynamic equatiion included the joint disturbance torque characteristics. Numerical example of 3 joint planar redundant robot manipulator is simulated. In the 2-norm minimization of joint disturbance torque we compared pseudoinverse local optimization with proposed technique, and the results showed better the proposed technique. So the proposed technique can be highly precision controlled redundant robot manipulators in the joint servo control.

• Journal of Industrial Technology
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• v.18
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• pp.289-293
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• 1998

In a independent joint servo control of robots, the performance of the control is influenced greatly by the joint interaction torques including Coriolis and centrifugal forces. These act as disturbance torques to the control system. As the speed of the robot increases, the effect of this disturbance torque increase, and makes the high speed - high precision control more difficult to achieve. In this paper, a solution to the optimal path placement problem is presented that minimizes the joint disturbance torque during a straight line motion. The proposed method is illustrated using computer simulation. The proposed solution method can be applied to the class of robots that are controlled by independent joint servo control, which includes the vast majority of industrial robots.

• Journal of IKEEE
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• v.16 no.3
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• pp.235-243
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• 2012

In this study, we developed two legged multi-joint robot by using wireless servo motor that was applied by wireless sensor network technology, which is widely used recently, and performed an experiment of walking method of two legged multi-joint robot. We constructed the star network with servo motors which were used at each joint of two-legged robot. And we designed the robot for operation by transmission of joint control signal from main control system or by transmission of the status of each joint to the main control system, so it operates with continuously checking the status of joints at same time. We developed the humanoid robot by using wireless digital servo motor which is different from existing servo motor control system, and controlled it by transmitting the information of angles and speeds of robot joints to the motor(node) as a feedback through main control system after connecting power and setting up the IDs to each joint. We solved noisy problem generated from wire and wire length to connection point of the control device by construction of the wireless network instead of using existing control method of wiring, and also solved problem of poor real time response to gait motion by controlling the position with continuous transmission of control signals to each joint. And we found that the effective control of robot is able by performing the simulation on walking motion in advance with the developed control algorithm which was downloaded into installed memory. Also we performed the stable walking with two-legged robot by attaching pressure sensor to robot sole. And we examined the robot gait operated by application of calculated algorithm on robot movement to each joint. In this study, we studied the method of controlling robot gait motion by using wireless servo motors and measured the torque applied to each joint, and found that the developed wireless servo motor by ZigBee sensor network offers easier control of two legged robot gait and better circuit configuration of it than the existing wired control system could do.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.10 no.2
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• pp.244-253
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• 2003

Purpose: This study was done for the purpose of testing the effects of hand moxibustion on pain in the knee joint, range of motion of the knee, and discomfort during ADL in elderly persons with knee joint pain. Method: Nonequivalent control group pre-post test research design was used. The participants were 35 elders who had knee joint pain. Sixteen were assigned to the experimental group and 19 to the control group. The instruments used for this study were the CRS (Graphic rating scale) for knee joint pain, goniometer for knee joint ROM, and modified ADL questionnaire developed by Lee. Analysis of data was done by percents, means and standard deviation, $x^2$-test, t-test, and ANCOVA using SPSS WIN 10.0. Result: The pain score for the right knee joint after hand moxibustion was significantly different between the experimental group and the control group after hand moxibustion (p=.035). The pain score for the left knee joint was not significantly different between the experimental group and the control group after hand moxibustion (p=.075). Right and left knee ROM scores were significantly different between the experimental group and the control group after hand moxibustion (Right p=.000, Left p=.034). Discomfort of ADL score was not significantly different between the experimental group and the control group after hand moxibustion (p=.053). Conclusion: In summary, knee joint pain in elders after hand moxibustion decreased and knee ROM in elders after hand moxibustion increased. So it would be useful for nurses to provide hand moxibustion as an alternative therapy to elders with knee joint pain in the community and thus reduce joint pain and increase knee ROM.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.418-429
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• 2018

This paper studies the decentralized position/force control problem for constrained reconfigurable manipulator without torque sensing. A novel joint torque estimation scheme that exploits the existing structural elasticity of the manipulator joint with harmonic drive model is applied for each joint module. Based on the estimated joint torque and dynamic output feedback technique, a decentralized position/force control strategy is presented. In order to solve the problem of controller parameter perturbation, the non-fragile robust technique is introduced into the dynamic output feedback controller. Subsequently, the stability of the closed-loop system is proved using the Lyapunov theory and linear matrix inequality (LMI) technique. Finally, two 2-DOF constrained reconfigurable manipulators with different configurations are applied to verify the effectiveness of the proposed control scheme in numerical simulation.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.133-140
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• 1993

In this paper, we prpose a method for tracking optimally a spatial trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint euqations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation result of a flexible planar manipulator is presented.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.513-518
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• 1998

In this paper, a robust fault-tolerant control scheme for robot manipulators overcoming actuator failures is presented. The joint(or actuator) fault considered in this paper is the free-swinging joint failure and causes the loss of torque on a joint. The presented fault-tolerant control framework includes a normal control with normal(non-failed) operation, a fault detection and a fault-tolerant control to achieve task completion. For both no uncertainty case and uncertainty case, a stable normal con-troller and an on-line fault detection scheme are presented. After the detection and identification of joint failures, the robot manipulator becomes the underactuated robot system with failed actuators. A robust adaptive control scheme of robot manipulators with the detected failed-actuators using the brakes equipped at the failed(passive) joints is proposed in the presence of parametric uncertainty and external disturbances. To illustrate the feasibility and validity of the proposed fault-tolerant control scheme, simulation results for a three-link planar robot arm with a failed joint are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.1029-1038
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• 2009

This paper proposes a gain switching algorithm for joint position control of a hydraulic humanoid robot. Accurate position control of the lower body is one of the basic requirements for robust balance and walking control. Joint position control is more difficult for hydraulic robots than it is for electric robots because of an absence of reduction gear and better back-drivability of hydraulic joints. Backdrivability causes external forces and torques to have a large effect on the position of the joints. External ground reaction forces therefore prevent a simple proportional-derivative (PD) controller from realizing accurate and fast joint position control. We propose a state feedback controller for joint position control of the lower body, define three modes of state feedback gains, and switch the gains according to the Zero Moment Point (ZMP) and linear interpolation. Dynamic equations of hydraulic actuators were experimentally derived and applied to a robot simulator. Finally, the performance of the algorithm is evaluated with dynamic simulations.

• Journal of Engineering Education Research
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• v.19 no.3
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• pp.44-53
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• 2016

In the engineering students, MSC is the most important basic areas in education. Also, the calculus is a main subject in the MSC. So calculus has been operating the annual number of courses at the university. We introduced the concept of joint control ; the joint syllabus, test and assessment. In harsh conditions to maintain joint control system of the calculus, we built a computer-aided-system to manage web-based result processing system. In this paper, we discussed the necessity and effectiveness of joint control system for calculus.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.101-112
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• 2007

Purpose : The purpose of this study was to evaluate influence of sacroiliac joint mobilization on lower extremity muscle strength. Methods : The subjects were consisted of thirty patients who had Leg length inequality(LLI) of more than 10mm(16 females. 14 males) from 21 to 41 years of age(mean aged 24.87). All subjects randomly assigned to sacroiliac joint mobilization group(n=15), control group(n=15). sacroiliac joint mobilization group received sacroiliac joint mobilization about 10 minutes for 3 times per week during 4 weeks period. Control group not received intervention during 4 weeks period. The tape measure method(TMM) was used to measure functional Leg length inequality. Biodex System 3 Pro was used to measure strength of Knee extension & flexion. All measurements of each subjects were measured at pre-test, 2weeks post-test and 4weeks post-test. Results : 1. The LLI of sacroiliac joint mobilization group was significantly reduced according to within treatment period(p<.05), most significantly reduced between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more reduced than control group(p<.05). 2. The knee extension strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). 3. The knee flexion strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). Conclusion : sacroiliac joint mobilization can reduce LLI and increased lower extremity muscle strength.