• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.511-516
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• 2016

Guaranteeing the safety of human workers around robots has become an important issue with the increasing demand for human-robot collaboration in industrial production lines. This study proposes a robot manipulator equipped with a counterbalancing mechanism that reduces the power of actuators required to drive the robot, thus keeping a human worker safer in a human-robot collaborative environment. A counterbalancing torque that exactly cancels out the gravitational torque in the proposed mechanism is generated by restoring the force of a spring in the counterbalancing mechanism. A prototype design and experimental results are presented to verify the effectiveness of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.1
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• pp.77-96
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• 1989

In diesel engines, it is inevitable that the torsional vibration is produced by the fluctuation of engine torque. Therefore, if the occurence of torsional vibration is confirmed in the design stage or the torsional vibration is observed on the bed of test run, it is necessary to establish some preventive measures to avoid dangerous conditions. Major preventive measures are as follows : 1. Changing the natural frequency of shaft system. 2. Repressing the vibration amplitude by the damping energy. 3. Counterbalancing the exciting torque by the resistant torque. 4. Counterbalacing the harmonic component of exciting energy. In above methos, the damper is the last measure to be used for controlling the torsional vibration. In this thesis, the design of viscous damper that absorbs the exciting energy is investigated and a number of problems associated with the design of viscous damper are treated and a computer pregram for the process of damper design is developed. A viscous damper for a high speed diesel engine is designed and its effect is simulated by the author's computer program.

• Korean Institute of Interior Design Journal
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• no.6
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• pp.28-37
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• 1995

As we approach the end of the twentieth century, it seems we need a new way to express the thoughts, needs, and values that are undergoing a drastic change and a new strategy to create diverse cultural forms that would reflect and incorporate such changes. In this study, I am introducing the chaos theory as a new way of thinking that would help counterbalancing the deter-ministic world-view and forging a harmonious unity of man and his environment. As a creative principle, the theory seems to offer an unlimited number of structural possibilities for art and design. In fine, this study discuss-es the reductive nature of modernist approach and offer instead the chaos theory that is more probabilistic and capable of greater diversity.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.11-18
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• 2017

Static balance of an articulated robot arm at various configurations requires a torque compensating for the gravitational torque of each joint due to the robot mass. Such compensation torque can be provided by a spring-based counterbalance mechanism. However, simple installation of a counterbalance mechanism at each pitch joint does not work because the gravitational torque at each joint is dependent on other joints. In this paper, a 6 DOF industrial robot arm based on the parallelogram for multi-DOF counterbalancing is proposed to cope with this problem. Two passive counterbalance mechanisms are applied to pitch joints, which reduces the required torque at each joint by compensating the gravitational torque. The performance of this mechanism is evaluated experimentally.

• Journal of Korean Academy of Nursing
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• v.44 no.1
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• pp.41-54
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• 2014

Purpose: The purpose of the study was to explore and describe the experience of adult Korean children who are caregivers for parents institutionalized with dementia. Methods: Participants were fourteen adult children caregivers of elders institutionalized with dementia. Data were collected through in-depth unstructured interviews with individual participants from August to November, 2012. Theoretical sampling was used to the point of theoretical saturation. Data were analyzed using Strauss and Corbin's Grounded Theory Method. Results: From open coding, 67 concepts, 29 sub-categories, and 14 categories were identified. Analysis revealed that the core category of the experience of adult children caring for their parents institutionalized with dementia was 'enduring the role of a prop' consisting of four phases: initial turmoil, exploration, role adjustment, and acclimation. To manage the role of a prop, participants utilized various action/interactional strategies such as overcoming the unfamiliarity, overseeing the nursing home care, and counterbalancing the caring roles. As a result, participants experienced ambivalence towards the existence of parents with dementia, changes in family relationships, altered viewpoint towards nursing homes, and restructuring of life. Conclusion: In-depth understanding of the experience will guide nurses to promote effective interventions in order to better support the Korean family caregivers of parents institutionalized with dementia.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.481-488
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• 2000

This paper presents a new passive gravity -compensating system for articulated robot manipulators. The system, which consists of linear zero- free -length springs, achieves exact counterbalancing o f the gravitational loads throughout the entire range of the manipulator workspace, A basic concept is to design springs such that the total potential energy of the system including the manipulator and the springs should be maintained constant. A prototype has been developed for a direct-drive five-bar manipulator and its performances have been investigated. Results show that the gravity-induced motor torques have been reduced to less than 5% of those of uncompensated robots. Also, the gravity-compensating system simplifies the position control algorithm while maintaining the trajectory-tracking errors in a satisfactory level. In conclusion, the proposed system efficiently improves the manipulator performances by reducing the driving motor size and the energy consumption as well as by simplifying the control systems.

• Journal of Drive and Control
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• v.12 no.4
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• pp.35-40
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• 2015

A gas spring provides support force for lifting, positioning, lowering, and counterbalancing weights. It offers a wide range of reaction force with a flat force characteristic, simple mounting, compact size, speed controlled damping, and cushioned end motion. The most common usage is as a support on a horizontally hinged automotive tail gate. However, its versatility and ease of use has been applied in many other industrial applications ranging from office equipment to off-road vehicles. The cylinder of a gas spring is filled with compressed nitrogen gas, which is applied with equal pressure on both sides of the piston. The surface area of the rod side of the piston is smaller than the opposite side, producing a pushing force. The magnitude of the reaction force is determined by the cross-sectional area of the piston rod and the internal pressure inside the cylinder. The reaction force is influenced by many design parameters such as initial chamber volume, diameter ratio, etc. In this paper, we investigated the reaction force characteristics and carried out parameter sensitivity analysis for the design parameters of a gas spring.

• Journal of the Korean institute of surface engineering
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• v.45 no.6
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• pp.272-277
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• 2012

The hull of a fast sailing aluminium ship are generally prone to erosion owing to the impact of seawater. At this time, synergistic effects of the erosion and the corrosion by aggressive ions such as chlorides tend to aggravate the damage. There have been various attempts, including selection of erosion-resistant materials, cathodic protection and addition of corrosion inhibitors, to overcome damage by erosion or corrosion under marine environments. These approaches, however, have limits on identifying the damage mechanism clearly, because they depend on analogical interpretation by correlating two damage behaviors after the individual studies are assessed. In this research, it was devised a hybrid testing apparatus that integrates electrochemical corrosion test and cavitation test, and thus the erosion-corrosion behavior by cavitation was investigated more reliably. As a result, the slightest damage was observed at the potentials between -1.6 V and -1.5 V. This is considered to be due to a reflection or counterbalancing effect caused by collision of the cavitation cavities and the hydrogen gas formed by activation polarization.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.155-161
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• 2019

We introduces a mobile robot that can navigate on a power transmission line arranged in bundled conductors. The designs of the proposed robot are performed for navigation on bundled conductors, and the navigation method for bundled conductors and obstacle avoidance are presented. The robot consists of 13 degrees of freedom (DOF) with a symmetrical structure for the left and right parts, including the four wheel joints. The navigation method is designed using a combination of three motion primitives such as linear motion of counterbalancing box, linear motion of robot arm, and rotational motion of wheel part. To examine the performance of the proposed robot, navigation simulations are conducted using $ADAMS^{TM}$. The robot navigations were simulated on obstacle environments that consisted of two- and four-conductor bundles. Based on the simulation results, the performance of the proposed robot was reviewed through the analysis of the trajectories of end-effectors. We confirmed that the proposed robot was capable of achieving optimal navigation on bundled conductors that included obstacles.

• Journal of Korean Academy of Nursing
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• v.23 no.2
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• pp.245-254
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• 1993

The purpose of this study was to identify effective methods to minimize increases in intracranial pressure(IICP ) during endotracheal suction by means of comparing two methods of hyperventilation and oxygen supply before and after endotracheal suction. In order to evaluate the effects of these two methods, the ICP during suctioning and the sustained time of IICP were measured. For hyperventilation, ambu-bagging was done 10 times for 30 seconds with a tidal volume of 800-900m1. For oxygen supply, 100 percent oxygen was supplied for 2 minutes before and after suction. The subjects for this study were 12 neurosurgical patients who had had a subarachnoid bolt inserted for ICP monitoring and they were all on mechanical ventilatory support in a surgical intensive care unit of Seoul National University Hospital from July 1, 1991 to March 31, 1992. In each patient hyperventilation was performed five times and oxygen supply was given five times and intracranial pressures were measured immediately before and every 30 seconds for 15 minutes after suction. For case assignments counterbalancing and repeated measure designs were combined. And so the total number of experiments were sixty for each group. The effects of hyperventilation and oxygen supply on the IICP and the sustained time of IICP after suction were analyzed by t-test. The results of study were as follows 1. There was a significant difference between the two groups in the increased ICP during suction (t=2.49, p=.014). 2. The sustained time of IICP after suctioning in the oxygen supply group was shorter than that in the hyperventilation group(t=2.35, p=.020) In summary, the Increase in the ICP during suction was lower and the time for the ICP to return to the presuction level was shorter in the oxygen supply group as compared to the hyperventilation group. Therefore, oxygen supply can be re commended before and after endotracheal suction.