• Title/Summary/Keyword: Loop Wheel

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Flexible Loop Wheel Mechanism for Intestine Movement (탄성 루프형 바퀴를 이용한 장 내 이동 메커니즘)

  • Im, Hyeong-Jun;Min, Hyeon-Jin;Kim, Byeong-Gyu;Kim, Su-Hyeon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.2
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    • pp.314-321
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    • 2002
  • An endoscope is usually inserted into the human body for the inspection of the gullet, stomach, and large intestine (colon) and this may cause discomfort to patients and damage to tissues during diagnostic or therapeutic procedures. This situation necessitates a self-propelling endoscope. There are many kinds of mechanism to move in a rigid pipe. However, these methods are difficult to apply directly to the endoscope. The main reason is that human intestine cannot be considered as a uniform, straight, and rigid pipe. This paper proposes a flexible loop wheel mechanism, which is adaptable to the human intestine. This mechanism is designed and fabricated by a simple modeling, and tested by an experiment. Finally, the actuator is inserted into the pig colon.

In-process Truing of Metal-bonded Diamond Wheels for Electrolytic In-process Dressing (ELID) Grinding

  • Saleh, Tanveer;Biswas, Indraneel;Lim, Han-Seok;Rahman, Mustafizur
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.3
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    • pp.3-6
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    • 2008
  • Electrolytic in-process dressing (ELID) grinding is a new technique for achieving a nanoscale surface finish on hard and brittle materials such as optical glass and ceramics. This process applies an electrochemical dressing on the metal-bonded diamond wheels to ensure constant protrusion of sharp cutting grits throughout the grinding cycle. In conventional ELID grinding, a constant source of pulsed DC power is supplied to the ELID cell, but a feedback mechanism is necessary to control the dressing power and obtain better performance. In this study, we propose a new closed-loop wheel dressing technique for grinding wheel truing that addresses the efficient correction of eccentric wheel rotation and the nonuniformity in the grinding wheel profile. The technique relies on an iterative control algorithm for the ELID power supply. An inductive sensor is used to measure the wheel profile based on the gap between the sensor head and wheel edge, and this is used as the feedback signal to control the pulse width of the power supply. We discuss the detailed mathematical design of the control algorithm and provide simulation results that were confirmed experimentally.