• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.44-49
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• 1999

This paper is concerned with the theoretical and experimental study on the force conrtrol of a miniature robotic gripper. The gripper is an uniform flexible cantilever equipped with a distributed set of compact force sensor. As an actuator piezoelectric acturator, piezoelectric acturator is fixed with cupper plate at which the beam is clamped. The mathematical model of the assembled electro-mechaincal system is developed. The force sensor is described by a set of concentrated mass-spring system. The formulated equations of motion are applied to he study of a control problem where the gripper is commanded to grip an object The usefulness of the PID control technique is verified by experiment.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.491-498
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• 1998

Transplanting process during the tissue culture of potato seedlings is costly, since the cost of highly skilled labor working in the sanitary environment takes up about 60-70% of the production cost. The objective of this study was to develop a soft gripper of a transplanting robot system for the labor-saving tissue culture. The prototype of the soft gripper was consisted of power-transmitting part finger and plant contacts. The power transmitting part transformed the rotating motion of a step motor to the reciprocating motion of the finger. Plant stems used in the test were potato seedlings cultured for six weeks. The dimensional characteristics of cultured seedlings, the compressive strengths of the stems, the extractive force from the culture medium and the gripping force of the finger were measured. A proper gripping force was found to be 0.343N at the extractive force of 0.41N when the plant contacts were made of silicon. Sixteen plants out of 70 trials were tangled with others, resulting in the success rate of 77.1%.

• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.325-332
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• 1997

The use of a robotic transplanter reduces the labor requirement in the greenhouse by carrying out repetitive tasks in an accurate and reliable manner. The transplanter manipulates seedlings by means of end-effector. The end-effector is designed differently from an industrial robot because it manulates biological seedlings of variable size, shape, position, and orientation. This study was conducted to develop an end-effector of a robotic transplanter for bedding plants. The development of an end-effector included selection of the best finger type for the transplanting operation. The performance of developed end-effector was tested and compared with two different transplanting schemes depending on the leaf-orientation consideration. The end-effector developed in this research reliably handled seedlings during transplanting task. Results showed that the shovel type finger was suitable for transplanting with the damaging seedlings.

• Journal of Biosystems Engineering
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• v.23 no.3
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• pp.271-276
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• 1998

A gripper mechanical design using a pneumatic system was developed to successfully grip, hold, and release a seedling plug for transplanting it. The gripper comprised of two air cylinders and shovel-type fingers. The gripper can grasp and hold a seedling by sliding the two fingers attached to the two separate air-cylinders, mounted at an angle of 15$^{\circ}$ When releasing a plug, retraction of the fingers gives a seedling little attachment to the gripper. To prevent seedling from attaching to the fingers, press-plates were attached to the end of the gipper. Transplanting performance of the developed gripper was tested with cucumber seedlings at different soil moisture contents. Overall transplanting performance of developed gipper was higher than the performance of the previously developed gripper. Best transplanting result was achieved at medium level of soil moisture content.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.12a
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• pp.88-98
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• 1997

This study was conducted to develope the gripper of a robotic transplanter for bedding plants. Specific objectives of this study were 1) to develope the gripper for plug tray seedlings and 2) to find the suitable finger type for transplanting. The performance of gripper was tested and compared by two different transplanting methods, which were to consider the leaf position of seedlings and not to consider. The results of this study are summarized as follows. (1) The gripper of a robotic transplanter was developed and tested with 4 different finger type. (2) The shovel type finger was suitable for transplanting with the least percent of damaged seedlings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.251-255
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• 2003

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate super-elastic alloy based micro gripper. It is tested to present improvement of mechanical performance. For integration of force sensor on the micro gripper, the sensor design based on the piezoelectric polymer PVDF film and fabrication process are presented. The calibration and performance test of force sensor integrated micro gripper are experimentally carried out. The force sensor integrated micro gripper is applied to perform fine alignment tasks of micro opto-electrical components. It successfully supplies force feedback to the operator through the haptic device and plays a main role in preventing damage of assembly parts by adjusting the teaching command.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1772-1777
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• 2003

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate super-elastic alloy based micro gripper. It is tested to present improvement of mechanical performance. For integration of force sensor on the micro gripper, the sensor design based on the piezoelectric polymer PVDF film and fabrication process are presented. The calibration and performance test of force sensor integrated micro gripper are experimentally carried out. The force sensor integrated micro gripper is applied to perform fme alignment tasks of micro opto-electrical components. It successfully supplies force feedback to the operator through the haptic device and plays a main role in preventing damage of assembly parts by adjusting the teaching command.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.501-502
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• 2006

In-plane type micro piezoelectric micro grippers with pneumatic lines for manipulation biological cells and micro parts were designed, fabricated, and characterized. Micro grippers were fabricated through the final micro-sanding process after wafer level bonding between the etched 4' Si wafer with pneumatic channels and 4' glass wafer. Displacements between two jaws of fabricated micro grippers were linearly increased with applying voltages to piezoelectric actuator. In the case of applying 80 V, the displacement between two jaws was $160{\mu}m$. Using fabricated micro grippers, manipulation tests for biological cell and micro parts with the sizes less than $100{\mu}m$ are in process.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.77-84
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• 2006

This paper describes the design and implementation of a robot's gripper control system. In order to safely grasp an unknown object using the robot's gripper, the gripper should detect the force of gripping direction and the force of gravity direction, and should perform the force control using the detected forces and the robot's gripper control system. In this paper, the robot's gripper control system is designed and manufactured using DSP(Digital Signal Processor), and the gripper is composed of two 6-axis force/moment sensors which measures the Fx force(force of x-direction), Fy force, Fz force, and the Mx moment(moment of x-direction), My moment, Mz moment at the same time. The response characteristic test of the system is performed to determine the proportional gain Kp and the integral gain Ki of PI controller. As a result, it is shown that the developed robot's gripper control system grasps an unknown object safely.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.154-154
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• 2004

초기 직경이 500$\mu\textrm{m}$인 텅스텐 봉을 전해에칭을 통하여 끝단 직경이 수 $\mu\textrm{m}$인 텅스텐 팁으로 가공하였다. 그리고, 적절한 전처리 과정을 거친 다증벽 탄소나노튜브를 제작된 텅스텐 팁 끝에 적절한 매니퓰레이션을 통하여 부착하였다. 이렇게 제작된 나노 팁(텅스텐 팁과 탄소나노튜브로 구성)은 매우 긴 탄소나노튜브의 길이 때문에 나노 팁으로 사용하기에 부적절한 경우가 많다. 즉, 나노 그리퍼로서 사용하기에는 적합하지 않은 경우가 있다. 이러한 점을 극복하기 위하여 전해에칭을 이용하여 나노 팁의 길이를 나노 그리퍼로 사용하기에 적합하도록 조절하였다.(중략)