• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.115-123
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• 2017

This paper presents the design and the control performance of a novel dynamic compliant-arm support with parallel elastic actuators that was developed to assist with the daily living activities of those whose arms are compromised by muscular disease or the aging process. The parallel elastic-arm support consists of a compliant mechanism with combined passive and active components for human interaction and to reach the user's desired positions. The achievement of these tasks requires impedance control, which can change the virtual stiffness, damping coefficients, and equilibrium points of the system; however, the desired-position tracking by the impedance control is limited when the end-effector weight varies according to the equipping of diverse objects. A prompt algorithm regarding weight calibration and friction compensation is adopted to overcome this problem. A result comparison shows that, by accurately assessing the desired workspace, the proposed algorithm is more effective for the accomplishment of the desired activities.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.119-125
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• 2005

The current automotive is seeking the improvement of performance, the prevention of environmental pollution and the saving of energy resources according to miniaturization and lightweight of the components. And the variance analysis on the basis of structure analysis and DOE is applied to the lower control am. We have proposed a statistical design model to evaluate the effect of structural modification by performing the practical multi-objective optimization considering weight, stress and fatigue lift. The lower control arm is performed the fatigue analysis using the load history of real road test. The design model is determined using the optimization of acquired load history with the fatigue characteristic. The characteristic function is made use of the optimization according to fatigue characteristics to consider constrained function in the optimization of DOE. The structure optimization of a lower control arm according to fatigue characteristics is performed. And the optimized design variable is D=47 m, T=36mm, W=12 mm. In the real engineering problem of considering many objective functions, the multi-objective optimization process using the mathematical programming and the characteristic function is derived an useful design solution.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.595-601
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• 2011

This paper presents balancing control of inverted pendulum on the ROBOKER arm using visual information. The angle of the inverted pendulum placed on the robot arm is detected by a stereo camera and the detected angle is used as a feedback and tracking error for the controller. Thus, the overall closed loop forms a visual servoing control task. To improve control performance, neural network is introduced to compensate for uncertainties. The learning algorithm of radial basis function(RBF) network is performed by the digital signal controller which is designed to calculate floating format data and embedded on a field programmable gate array(FPGA) chip. Experimental studies are conducted to confirm the performance of the overall system implementation.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.682-688
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• 2000

To improve the performance of a flexible robot arm one of the important things is the vibration displacement measurement of a flexible arm. Many types of sensors have been used to measure it, The most popular has been strain gauges which measures the deflection of the beam,. Photo sensors have also been for detecting beam displacement and accelerometers are often used to measure the beam vibration. But the vibration displacement can be obtained indirectly from these sensors. In this article a vision sensor is used as a displacement sensor to measure the vibration displacement of a flexible robot arm. Several schemes are proposed to reduce the image processing time and increase its accuracy. From the experimental results it is seen that the vision sensor can be an alternative sensor for measuring the vibration displacement and has a potential for on-line tip position control of flexible robot systems.

• Journal of Korean Biological Nursing Science
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• v.14 no.4
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• pp.300-307
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• 2012

Purpose: The purpose of this research was to develop and prove the effectiveness of structured arm exercise, which was used to reduce Arteriovenous Fistula (AVF) and Arteriovenous graft (AVG) stricture of hemodialysis patients. Methods: Quasi-experimental research design with non-equivalent control group was applied. 26 Subjects were participated in this study. 12 of hemodialysis patients who do not have a normal range of Static Intra Access Pressure Vein (SIAPV) score in the last three months were assigned to the experimental group and 14 patients who have a normal range of SIAPV score in the last three months to the control group. To analyze the collecting data after structured arm exercise, non parametric method with the repeated measures ANOVA by the Friedman test and Wilcoxon Signed Ranks Test for post-hoc test was performed. Results: Unlike the experimental group after three months, the control group's SIAPV data went over the normal range. The experimental AVF group showed a difference in data after month 2 and month 3. - In AVG group, there were clear differences in each month of the test. Conclusion: This study proved that structured arm exercise therapy could be a simple and effective intervention. It is suggested to be actively utilized for hemodialysis patients.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1322-1325
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• 1997

A new feedback control law design techniqed usign of-off thrusters for the rotational maneuver of a flexible arm is discussed in this study. a two state on-off thruster actuator is taken as a primary actuation device for theis study. The on-off thruster operation is emulated in conjunction with the conventioal minimum-time trackig control law. The actuator input region is divided into two separate parts ; one is constant input and the other is time varying tegion. the new control law has potential applicatioin for the relatively low frequency structure such as large flexible space structure being currently used in various space echnology areas.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.905-908
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• 1987

A human operator has the ability to control a complicated system such as a gantry crane, an aircraft and a remote manipulator after enough training and learning. In this article, we attempt the positioning experiment of a flexible arm by a human operator. Flexible arm has nonlinearlity and infinite-degrees of freedom in general; thus it is difficult to obtain a control input. The operator interprets a given task and finds the procedure of operations. He devises an effective way of achieving the goal on the basis of his experience and knowledge about the task.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.5
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• pp.461-468
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• 1997

A real-time collision-free trajectory control method for dual arm robot system is proposed. The proposed method is composed of two stages; one is to calculate the minimum distance between two robot arms and the other is to control the trajectories of the robots to ensure collision-free motions. The calculation of minimum distance between two robots is, also, composed of two steps. To reduce the calculation time, we, first, apply a simple modeling technique to the robots arms and determine the interested part of the robot arms. Next, we apply more precise modeling techniques for the part to calculate the minimum distance. Simulation results show that the whole algorithm runs within 0.05 second using Pentium 100MHz PC.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.609-615
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• 2002

An application of a simple and effective learning control scheme to a robotic arm for exercise is presented. During exercises, the force applied by a .user to an exercise machine varies for different users and for different workouts of the same user. learning control is used to compensate for the difference between the actual force and the planned one. It is shown through simulation that the learning control method decreases tracking error quickly for both time-invariant and time-varying forcing functions.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.40-50
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• 1996

An unified compliant control algorithm to regulate the force by dual arms is proposed, where tow arms are treated as one arm in a kinematic viewpoint. The force error calculated form the information of two force/torque sensors attached to the end of each arm is transferred to minimum actuator coordinates, and then is distributed to total system actuator coordinates. The position adjustment at the total actuator coordinates is computed based on the effective computed based on the effective compliance matrix with respect to total actuator coordinates, which is obtained by coordinate transformation between the task coordinates and the total actuator coordinates. An experiment is carried out for dual arms with asymmetric kinematic structure to control an interaction force between manipulators and the environment. The performances of the proposed control algorithm are experimentally compared to those of dual arms employing master/slave scheme. The proposed compliant control algorithm not only ouperforms other algorithms, but also can be treated as an unified approach n the sense that it can be applied to arbitrary dual arm systems with general kinematic structures.