• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.281-286
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• 2004

The end-effector is the one of the important factors on development of the cucumber robot to harvester a cucumber. Three end-effectors were designed the single blade end-effector with one blade, the double blade end-effector with two blades and the triple blade end-effector with three blades. Performance tests of the end-effector, the fully integrated system, were conducted to determine the cutting rate by using two different kinds of cucumber. The success rates of cucumber cutting ratio of single end-effector, double end-effector and triple end-effector in laboratory. were 61.7%, 95%, 86.7%, respectively. The cutting rate of single blade or double blade was a little difference with respect to the different diameters of cucumber stem. However, the success cutting rate of the end-effector with triple blade was 61.7% under 29mm diameter of a grabbing stem section. The triple end-effector was not suitable for harvesting a cucumber, but was considered to be suitable for harvesting a grape, an apple and a tomato. The success rate of cucumber cutting ratio of triple end-effectors in greenhouse was 84%. The failure cutting rate was 16% which are due to abnormal shape of cucumber fruit.

• Industrial Engineering and Management Systems
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• v.3 no.1
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• pp.78-84
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• 2004

To optimize movement of a multi-joint robot arm is known to be a difficult problem, because it is a kind of redundant system. Although the end-effector is set its position by each angle of the joints, the angle of each joint cannot be uniquely determined by the position of the end-effector. There exist the infinite number of different sets of joint angles which represent the same position of the end-effector. This paper describes how to manage the angle of each joint to move its end-effector preferably on an X-Y plane with obstacles in the end-effector’s reachable area, and how to optimize the movement of a multi-joint robot arm, evading obstacles. The definition of “preferable” movement depends upon a purpose of robot operation. First, we divide viewpoints of preference into two, 1) the standpoint of the end-effector, and 2) the standpoint of joints. Then, we define multiple objective functions, and formulate it into a multi-objective programming problem. Finally, we solve it using multi-purpose genetic algorithm, and obtain reasonable results. The method described here is possible to add appropriate objective function if necessary for the purpose.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.359-366
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• 2010

This study proposes the design method for the robot rotation arm which the end effector that is connected in end of the arm keeps parallel motion even though the robot arm rotates. So far, most robot arm rotates together the end effector when the arm rotates. For this, this study proposes the mechanism that the arm is linked to each 4 parallel link so that rotation is possible by 4 pins, and the rotation arm connects 2 joints of diagonal line direction to a link in each 4 joint for rotation, and designs so that can change length of the link. For verification of design, this study targeted that develop the rotation arm for medical examination that use in ophthalmology. It is important that a medical robot offers comport to patient and design compactly so that medical examination and treatment space may can be defined enough. It is designed so that all drive elements may be positioned on interior of the arm and optimization of design for main parts was carried out in this study for this. The robot arm which is developed in this study manufactured to use by medical phoropter arm, and got good result by an experiment. The robot rotation arm which is proposed in this study is judged to contribute very effectively in case use of a medical robot arm for medical examination and treatment, also the robot arm which the end effector that is connected in the end of the arm needs to keep parallel motion. And, the robot arm which is developed in this study made an application as license.

• The Journal of Korea Robotics Society
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• v.15 no.2
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• pp.91-99
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• 2020

Fruit and vegetable harvesting robots have been widely studied and developed in recent years to reduce the cost of harvesting tasks such as labor and time. However, harvesting robots have many challenges due to the difficulty and uncertainty of task. In this paper, we characterize the crop environment related to the harvesting robot and analyzes state-of-the-art of the harvesting robot especially, in the viewpoint of robotic end-effector. The end-effector, an one of most important element of the harvesting robot, was classified into gripper and harvesting module, which were reviewed in more detail. Performance measures for the evaluation of harvesting robot such as test, detachment success, harvest success, and cycle time were also introduced. Furthermore, we discuss the current limitations of the harvesting robot and challenges and directions for future research.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.376-384
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• 2023

In this paper, we introduce an upper extremity rehabilitation robot, NREH (NRC End-effector based Rehabilitation arm at Home). Through NREH, stroke survivors could continuously exercise their upper extremities at home. NREH allows a user to hold the handle of the end-effector of the robot arm. NREH is a end-effector-based robot that moves the arm on a two-dimensional plane, but the tilt angle can be adjusted to mimic a movement similar to that in a three-dimensional space. Depending on the tilting angle, it is possible to perform customized exercises that can adjust the difficulty for each user. The user can sit down facing the robot and perform exercises such as arm reaching. When the user sits 90 degrees sideways, the user can also exercise their arms on a plane parallel to the sagittal plane. NREH was designed to be as simple as possible considering its use at home. By applying error augmentation, the exercise effect can be increased, and assistance force or resistance force can be applied as needed. Using an encoder on two actuators and a force/torque sensor on the end-effector, NREH can continuously collect and analyze the user's movement data.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.621-631
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• 1996

It is said that robot can be used for multi-purpose use by changing end effector or/and visual sensor with its software. In this study, it was investigated what multi-purpose robot for fruit-production was using a tomato harvesting robot and a robot to work in vineyard. Tomato harvesting robot consisted of manipulator, end-effector, visual sensor and traveling device. Plant training system of larger size tomato is similar with that of cherry-tomato. Two end-effectors were prepared for larger size tomato and cherry-tomato fruit harvesting operations, while the res components were not changed for the different work objects. A color TV camera could be used for the both work objects, however fruit detecting algorithm and extracted features from image should be changed. As for the grape-robot , several end-effector for harvesting , berry thinning , bagging and spraying were developed and experimented after attaching each end-effector to manipulator end. The manipulator was a polar coordinate type and had five degrees of freedom so that it could have enough working space for the operations. It was observed that visual sensor was necessary for harvesting, bagging and berry-thinning operations and that spraying operation requires another sensor for keeping certain distance between trellis and end-effector. From the experimental results, it was considered that multi-operations by the same robot could be appropriately done on the same or similar plant training system changing some robot components . One of the important results on having function of multi-operation was to be able to make working period of the robot longer.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.164-173
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• 1999

Robot calibration needs accurate measurements of robot end-effector position at a number of different robot configurations. One of the efficient ways of the measurement is "Touching on Jig" method suggested in [7], which utilizes a touch sensor and a fixture consisting of various sizes of blocks. By moving the end-effector to touch the surface of a block whose position relative to the other is known, the end-effector position relative to the fixture coordinate system can be obtained at the instant of touching. However, the global size of fixture is too small to cover the various configurations of the robot. Because of the manufacturing difficulties, the fixture cannot be manufactured large enough for well distributed position measurement. It results in the improvement of robot accuracy only in the limited space near to the fixture rather than over the whole space of the robot working volume. The paper proposes a method to resolve the above problem by measuring the end-effector positions with respect to several different coordinate system using the same measurement devices. It is found that the proposed method leads the improvements of robot position accuracy over the large space of working volume. The experimental studies are performed to show the validity of the method and their results are discussed.

• Journal of the Semiconductor & Display Technology
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• v.2 no.3
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• pp.31-36
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• 2003

On this study, an E.E(End-Effector) for the 300 mm wafer transfer robot system is newly suggested. It is a mechanical type with $180^{\circ}$ rotating ranges and is composed of 3-point arms, two plate springs and single-axis DC motor controlled by microchip. To design, relationship between the gripping force and the wafer deformation is analyzed by FEM. By analytic results, the gripping force for 300 mm wafer is confirmed as 255~274 gf. From experimental results on gripping force, repeatable position accuracy and gripping cycle times in a wafer cleaning system, we confirmed that the suggested E.E was well designed to satisfiy on the required performance for 300 mm wafer transfer robot system.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.311-317
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• 2019

Direct teaching is an essential function for collaborative robots for easy use by non-experts. For most robots, direct teaching is implemented only in joint space because the realization of Cartesian space direct teaching, in which the orientation of the end-effector is fixed while teaching, requires a measurement of the end-effector force. Thus, it is limited to the robots that are equipped with an expensive force/torque sensor. This study presents a Cartesian space direct teaching method for torque-controlled collaborative robots without either a force/torque sensor or joint torque sensors. The force exerted to the end-effector is obtained from the external torque which is estimated by the disturbance observer-based approach with the friction model. The friction model and the estimated end-effector force were experimentally verified using the robot equipped with joint torque sensors in order to compare the proposed sensorless approach with the method using torque sensors.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.523-526
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• 1996

In this paper, robot endeffector tracking using sensory information from structured laser pattern diode, is described. In order to track robot endeffector robustly irrespective of translation, scaling and rotation of robot working tool, structured laser pattern is used as track feature. Structured laser patterns of crosshair, concentric circles, dot matrix, and parallel lines are illuminated to robot endeffector. Illuminated laser patterns are held invariently and coherently irrespective of various motions of robot endeffector. Extracting and tracking these invariant structured laser patterns as track feature, the whole system keeps tracking of the robot endeffector robustly and effectively provided that structured laser pattern is always assumed to aim at robot endeffector.