• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.267-267
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• 2000

We developed a human-sized BWR(biped walking robot) driven by a new actuator based on the ball screw which has high strength and high gear ratio. The robot overcomes the limit of the driving torque of conventional BWRs. Each leg of the robot is composed of three pitch joints and one roll joint. In all, a 10 degree-of-freedom robot with two balancing joints was developed. The BWR was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. In the performance test, the BWR peformed nice motions of sitting-up and sitting-down. Through the test, we could find capability of high performance in biped-walking.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1096-1098
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• 2000

This paper proposes a tension control to compensate friction loss using on-line friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension. accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The experimental results show improvement of tension control performance by the proposed friction compensation method.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.823-824
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• 2006

This paper proposes a novel structured 3-DOF(Degree-of-Freedom) spherical motor. 3-DOF spherical motor presents some attractive features by combining pitch, roll, yaw motion in a single joint. The proposed motor has pole which is electromagnetic in stator and rotor. poles produce magnetic flux through by exciting current then produce torque. We show a novel structured rotor to avoid mechanical overlapping of each coil in rotor. The validity of the analysis is confirmed by 3D finite element method.

• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.222-229
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• 2011

In this paper, we present the concept and main mission of the Crabster, an underwater walking robot. The main focus is on the modeling of drag and lift forces on the legs of the robot, which comprise the main difference in dynamic characteristics between on-land and underwater robots. Drag and lift forces acting on the underwater link are described as a function of the relative velocity of the link with respect to the fluid using the strip theory. Using the translational velocity of the link as the rotational velocity of the joint, we describe the drag force as a function of joint variables. Generalized drag torque is successfully derived from the drag force as a function of generalized variables and its first derivative, even though the arm has a roll joint and twist angles between the joints. To verify the proposed model, we conducted drag torque simulations using a simple Selective Compliant Articulated Robot Arm.

• Elastomers and Composites
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• v.43 no.2
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• pp.104-112
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• 2008

The ethylene propylene diene terpolymer (EPDM) blends with styrene butadiene rubber (SBR) were prepared from an open 2-roll mill following the conventional rubber blend method, and then cure characteristics, mechanical properties and ozone resistance were subsequently examined. With incorporation of SBR the torque value of the EPDM and SBR blends showed a gradual increase in the cure curve. The maximum torque value was obtained with lowest level at 25wt% of SBR and it was increased linearly with more than 25wt%. As the SBR loading increased scorch time and optimum cure time decreased. Hardness represented a maximum at 50wt% of SBR. However upper and lower than that value it decreased. It was found that the unfavorable characteristics of ozone resistance of pure SBR was significantly improved through the blending of SBR with EPDM.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.31-38
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• 2008

This Study discussed the roll forming process analysis of levitation rail for urban Maglev vehicle. To verify validity of roll forming process, we analyzed roll forming process for track shoe which is similar to levitation rail. The analysis process was composed of 12 passes and was performed for only 8 passes except overlapping passes. In the variation of temperature with each pass, surface temperature of the structure was cooled from initial $1200^{\circ}C$ to $1010^{\circ}C$ during 30 second before first pass, and central temperature and surface temperature was cooled to $980^{\circ}C$ and $900^{\circ}C$ in final pass, respectively. A length of structure after final pass is about 5 times longer than that before roll forming process. A strain of structure had a higher value in the inner part of the track shoe and show from minimum 2.5 to maximum 6.5. A torque applying on roll appear high in 2, 3 and 4 passes and a maximum value was $27,000ton{\cdot}mm$. Also it was analyzed that a load to the normal direction needs maximum 300ton.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.12
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• pp.1471-1481
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• 2009

In diesel engines, it is inevitable that the torsional vibration is produced by the fluctuation of engine torque. Therefore, it is necessary to establish preventive measures to diminish the torsional vibration. The sleeve spring type damper is one of the preventive measures for reducing the torsional vibration. In this study, the closed form equations to predict the spring constant of a sleeve spring and the torsional characteristics of the torsional vibration damper are proposed to calculate stiffness of the damper and verified their availability through the finite element analysis and experiments. And the stability of the sleeve spring torsional vibration damper is verified by analyzing the inner star and outer star, which are the core parts of the damper, and 2-roll bending process is proposed to manufacture sleeve spring. The program to calculate the initial radius including spring-back effect is developed, and the FEA method to analyze elasto-plastic problem was verified through analysis of 90$^{\circ}$bending process. The results of the analysis are in good agreements with those of the experiments. The newly proposed method can be used as an advanced technique that remarkably curtails cost of production and replaces the conventional forming.

• Elastomers and Composites
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• v.30 no.3
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• pp.195-206
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• 1995

To modify the NBR rubber roll which has poor abrasion and chemical resistance, NBR/PVC blends were prepared in various composition ratios. First of all, their miscibility and vulcanization characteristics were investigated. Their abrasion and chemical resistant properties and physical properties were also studied. DSC thermograms for NBR/PVC blends show only one Tg in the entire composition range, demonstrating a perfect miscibility. In the vulcanization characteristics tested by rheometer, maximum torque decreases as PVC contents increased. In the investigation of physical properties of NBR/PVC blends, hardness increases and elongation decreases along with the increasing contents of PVC. On the other hands, tensile strength increases with the increasing contents of PVC up to 11.1 wt. %, and then decreases with higher contents of PVC. While the abrasion resistance of NBR/PVC blends was similar to that of NBR itself, the chemical resistance of NBR/PVC blends was superior to that of NBR.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.2
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• pp.25-30
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• 2024

This study was conducted to develop the hanging type circular-patterned system that at maximizing the spatial efficiency of strawberry cultivation to increase yields, while also reducing labor and improving energy efficiency. The system consists of a cultivation bed units, longitudinal moving device, bed lifting device, front and rear transfer devices, lateral transfer device, nutrient supply device, and control unit. Performance testing revealed that the operational motor for longitudinal movement should have a torque of at least 0.1Nm based on the design weight and traction force of the cultivation bed unit. The power consumption required to move one cycle was calculated to be approximately 149Wh when performing harvesting or maintenance tasks for all 10 cultivation beds. Vibration angles measured during bed movement showed that the lateral transfer resulted in a roll angle ranging from -0.62° to 0.68° and a pitch angle ranging from -3.79° to 5.26°. For longitudinal transfer, the roll angle ranged from -3.37° to 3.36°, and the pitch angle ranged from -0.45° to 0.49°.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.57-61
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• 2005

This paper presents a new colonoscopy training simulator that includes a specialized haptic device and graphics algorithms to transfer haptic sensation through a long and flexible tube, and manage large number of polygons. The developed haptic device makes the colonoscope tube move along the two guiding rods in the translational direction. The torque of the roll motion is transferred by a timing belt and pulleys. A special guide is developed, which allows the force and torque from the motors to be transmitted to the user without loss. The haptic device is evaluated by physicians. One of the important skills of the colonoscopy, jiggling is incorporated for the first time by the developed sensor mechanism using photo-sensors. A colonoscope handle that shares the look, feel, and functions with the actual colonoscope, is developed with the necessary electronics inside. The number of polygons is reduced by an edge-collapse algorithm for real-time simulation. The algorithms to import CT data, to segment the colon image, to extract centerline of the colon, and to construct the colon surface, are integrated into a Colon Modeling Kit system that performs all these processes in real-time.