• Journal of the Korean Society of Industry Convergence
• /
• v.18 no.4
• /
• pp.216-223
• /
• 2015

Recently Manipulation capability is important for a robot. Interaction between a robot hand and objects can be properly controlled only is suitable sensors are available. Recently the tendency is to create robot hands more compact and high integrated sensors system, in order to increase the grasping capability and in order to reduce cabling through the finger, the palm and the arm. As a matter of fact, miniaturization and cabling harness represents a significant limitation to the design of small sized embedded sensor. Ongoing work is focusing on a flexible manipulation system, which consists of a dual flexible multi-fingered hand-arm system, and a dual active vision system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.10
• /
• pp.964-969
• /
• 2012

Robot hands capable of grasping or handling various objects are important for service robots to effectively aid humans. In particular, controlling a contact force and providing a compliant motion are essential when the hand is in contact with objects. Many dexterous robot hands equipped with force/torque sensors have been developed to perform force control, but they suffer from the complexity of control and high cost. In this paper, a low-cost robot hand based on SEA (Series Elastic Actuator), which is composed of compression spring, stretch sensor, and wire, is proposed. The grasping force can be estimated by measuring the compression length of spring, which would allow the hand to perform force control. A series of experimentations are carried out to verify the performance of force control of the proposed robot hand, and it is shown that it can successfully control the contact force without any additional force/torque sensors.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.108.4-108
• /
• 2002

This paper aims to derive a mathematical model of the dynamics of handling tasks in robot fingers which stably grasps and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for differential-algebraic equations of overall...

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.608-615
• /
• 2002

In recent years, Pressure to recycle has stemmed from environmental and economic reasons. This paper examines a new methodology that can estimate the disassemblability considering the recycling. Easy of disassembly estimation method outlined here is shown to provide one of several needed metrics for use during product design. This study suggests five main determining factors-fixing, grasping, access, disassembly and handling-as the five determining factors and determined to evaluate disassemblability. The evaluation based on disassemblability is demonstrated on an automobile parts example.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.4
• /
• pp.371-378
• /
• 2014

Manual materials handling tasks are the main risk factors for the work-related musculoskeletal disorders. Many assistant tools for manual materials handling are being used in various kind of industries. One of them is a 4-wheeled cart which is widely used in manufacturing factories, hospitals, etc. The major force required to control the 4-wheeled cart is pushing and pulling. There are two types of handles being used for the 4-wheeled cart : vertical type (two vertical handles), and horizontal type (one horizontal handle). This study tried to investigate the pushing forces and subjective discomforts (hand/writst, shoulder, low back, and overall) of the two handle types with different handle height and distance conditions. Twelve healthy male students (mean age = 23.4 years) participated in the experiment. The independent variables were handle angle (horizontal, vertical), handle height (low, medium, high), and handle distance (narrow, medium, wide). The full factorial design was used for the experiment and the maximum pushing forces were measured in 18 different conditions ($2{\times}3{\times}3$). Analysis of variance (ANOVA) procedure was conducted to test the effects of the independent variables on the pushing force and discomfort levels. Handle height and angle were found to be the critical design factors that affect the maximal pushing forces and subjective discomfort. In the middle height, subjects exerted higher pushing forces, and experience lower discomfort levels compared to the high, and low height. There was no statistical influence of the handle distance to the pushing forces and subjective discomfort levels. It was found out that the effects of the handle angle (horizontal and vertical) on both pushing force and subjective discomfort were statistically significant (p < 0.05). The vertical handle revealed higher pushing force and lower discomfort level than the horizontal handle. The reason for that was thought to be the different postures of the hand when grasping the handles. The horizontal handle induced pronaton of the hand and made hand posture more deviated from the neutral position.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.5
• /
• pp.537-544
• /
• 2019

In currently electronic systems, the speed of information integration has increased due to the development of electronic technology. However, due to the increase in the number of parts and groups, the product structure has become complicated. In this paper, a study was conducted to evaluate quantitatively the replacement of a small equipment. First, the level of the replacement was determined through the algorithm for the replacement level of parts. Next, we defined the ease of detail replacment, and the factors for each detail replacement. In order to calculate the weighting of the detail ease, we performed the analysis of the replacement process of subcomponents of communication exchanger and defined the evaluation criteria. Finally, the completion of the evaluation check sheet and the evaluation score table.

• The Journal of Korea Robotics Society
• /
• v.6 no.2
• /
• pp.130-140
• /
• 2011

This paper proposes an optimal posture for the task-oriented movement of dual arm manipulator. A stability criterion function which consists of three kinds of feature-representative parameters has been utilized to define the optimal posture. The first parameter is the force which is applied to the object. The torque of each joint and position of arm are attained from the current sensor and encoder, respectively. From these two data, the applied force to an object is estimated using sum of vectors of the joint torques estimated from the measured current. In order to investigate the robustness of each posture, the variation of the end-effector from the encoder information has been utilized as the second parameter. And for the last parameter for the optimality, the total energy consumption has been used. The total consuming energy of each posture can be computed from the current information and the battery voltage. The proposed robot structure consists of a mobile inverted pendulum and dual manipulators. In order to define the optimal posture for the each object, external disturbances are applied to the mobile inverted pendulum robot and the first and second parameters are investigated to find the optimal posture among the pre-selected most representative postures. Finally, the proposed optimal posture has been verified by the proposed stability criterion function which consists of total force to the object, the fluctuation of the end-effector position, and total energy consumption. The effectiveness of the proposed algorithms has been verified and demonstrated through the practical simulations and real experiments.

• Korean Journal of Occupational Health Nursing
• /
• v.7 no.2
• /
• pp.143-154
• /
• 1998

The purpose of this research is to suggest basic materials for the practical infection precaution program to protect health care workers from hospital infection by grasping their compliance level of Universal Precautions and examining the factors affecting them. The number of the health care workers we studied were 486, including the doctors, the nurses, and the lab technicians who were working in a university hospital. The period of this research was from Aug. 18th, 1997 to Aug. 30th, 1997. The method of the study was to measure the compliance level of Universal Precautions with the item of "Universal Precautions" established by CDC in 1987, and examine the questionnaire of 52 questions dividing related factors into socio-populational, individual, socio-psychological and organizational management ones. The data was analyzed by t-test. ANOVA, and chi-square test. The results were as follows : 1. An the compliance level of Universal Precautions, hand washing had the highest score(85.4%), and doctors(18.9%), nurses(44.0%), and lab technicians(7.6%), had a low compliance level in the safe handling of an injection syringe, and item not to handle patients and their samples when the subject suffered from dermatitis or injury had the lowest score of 17.1%. 23.3% of them said that they wear protection gown, goggles and mask. 2. Female's Compliance level of Universal Precautions Was higher than male. 3. The health care workers who had high recognition on Universal Precautions got significantly higher compliance level of Universal Precautions than those have low recognition on Universal Precautions(P<0.001). 4. The health care workers experienced a needle stick injury had a significantly higher compliance level of Universal Precautions than those who had not(P<0.000). 5. The health care workers who had infection protection education got a significantly higher compliance level of Universal Precautions than those who didn't(P<0.000). 6. The health care workers who had a firm belief in the effect of Universal Precautions got a higher compliance level of Universal Precautions than those who didn't. 7. The health care workers who had less conflicts between treating patient arid protecting them-selves got a higher compliance level of Universal Precautions than others with many conflicts. 8. The health care workers who had a high score in organizational management factors got a significantly higher compliance level of Universal Precautions than those with a low score(P<0.000). 9. Only 16.9 percent of the all respondents(82 in number) answered that they knew well or a little about the Universal Precautions, which is very low rate of recognition. 10. The variables which affected the score in organizational management factors were age, sex, education period, work experience, the kind of work, recognition on Universal Precautions, the experience of needle stick injury, revealing dangerous circumstance related to infection, and training on precaution again infection. According to the result above, compliance level of Universal Precautions showed high correlation with sex, the recognition on Universal Precautions, the experience of needle stick injury, training on precaution against infection, the belief in the effect of Universal Precautions, the recognition degree of conflicts and organizatinal management factors. These results could be used as the basic materials for the developing infection protection programs. Also, There should have a systematic training course to elevate a effective compliance level of Universal Precautions as well as the manageeent of infection protection programs.