• Journal of Sensor Science and Technology
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• v.15 no.6
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• pp.411-416
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• 2006

This paper describes the development of a 3-axis finger force sensor to grasp an unknown object safely in an intelligent robot's hand. In order to safely grasp an unknown object, robot's hand should measure the weight of an object and the force of grasping direction simultaneous. But, in the published papers, the grippers and hands equippd with the force sensor that could only measure the force of grasping direction, and grasped objects using their sensors. These grippers and hands can't safely grasp unknown objects, because they can't measure the weight of it. Thus, it is necessary to develop 3-axis force sensor that can measure the weight of an object and the force of grasping direction for an intelligent gripper. In this paper, 3-axis finger force sensor to grasp an unknown object safely in an intelligent robot's hand was developed. In order to fabricate a 3-axis finger force sensor, the sensing elements were modeled using parallel plate beams, and the theoretical analysis was performed to determine the size of sensing elements, then the 3-axis finger force sensor was fabricated. Also, the characteristic test of the developed 3-axis finger force sensor was performed.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.3 s.192
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• pp.47-54
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• 2007

This paper describes the development of the intelligent gripper with two 3-axis force sensor that can measure forces Fx, Fy, Fz simultaneously, for stably grasping an unknown object. In order to grasp an unknown object using an intelligent gripper softly, it should measure the force in the gripping direction and the force in the gravity direction, and perform the force control using the measured farces. Thus, the intelligent gripper should be composed of 3-axis force sensor that can measure forces Fx, Fy, Fz at the same time. In this paper, the intelligent gripper with two 3-axis force sensor was manufactured and its characteristic test was carried out. The fabricated gripper could grasp an unknown object stably. Also, the sensing element of 3-axis force sensor was modeled and designed with five parallel-plate beams, and 3-axis force sensor for the intelligent gripper was fabricated. The characteristic test of the made sensor was carried out.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.110-115
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• 2016

This paper describes the design and fabrication of a three-axis force sensor with three parallel plate structures(PPSs) for measuring force in a finger force measuring system for a spherical object catch. The three-axis force sensor is composed of a Fx force sensor, Fy force sensor and a Fz force sensor, and the elements of Fx force sensor and Fy force sensor are a parallel plate structure(PPS) respectively and Fz force sensor is two PPS. The three-axis force sensor was designed using FEM(Finite Element Method), and manufactured using strain-gages. The characteristics test of the three-axis force sensor was carried out. As a test results, the interference error of the three-axis force sensor was less than 1.32%, the repeatability error of each sensor was less than 0.04%, and the non-linearity was less than 0.04%.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.4
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• pp.309-316
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• 2016

In this study, we described the design of a three-axis force/torque sensor for measuring the force and torque in a lower-limb rehabilitation robot. The three-axis force/torque sensor is composed of Fx force sensor, Fz force sensor and Tz torque sensor. The sensing element for Fx force sensor and Tz torque sensor is used in a two-step parallel plate beam, and that of Fz force sensor is used in a parallel plate beam. The rated loads of Fx force sensor, Tz torque sensor and Fz force sensor are 300 N, 15 N m and 100 N, respectively. The three-axis force/torque sensor was designed using the finite element method, and manufactured using strain-gauges. The three-axis force sensor was further characterized. As a result, the interference error of the three-axis force/torque sensor was < 1.24%, the repeatability error of each sensor was < 0.03%, and the non-linearity was < 0.02%.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.226-232
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• 2016

This paper describes the design of a smart three-axis force sensor for measuring forces Fx, Fy and Fz. The smart three-axis force sensor is composed of a three-axis force sensor, a force-measuring device, housing and a cover, where the three-axis force sensor and the force-measuring device are inside the housing and the cover. The measuring device measures forces Fx, Fy and Fz from the three-axis force sensor, and calculates the resultant force using the measured forces, and then sends the resultant force and forces to a PC or other controller using RS-485 communication. The repeatability error and the non-linearity error of the smart three-axis force sensor are less than 0.03%, and the interference error of the sensor is less than 0.87%. It is thought that the sensor can be used for measuring forces in a robot, automatic systems and so on.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.5-11
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• 2002

This paper describes the methods for calibration and evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor. In order to use the sensor in the industry, it should be calibrated and its relative expanded uncertainty should be also evaluated. At present, the confidence of the sensor is shown with only interference error. However, it is not accurate, because the calibrated multi-axis force/moment sensor has an interference error as well as a reproducibility error of the sensor, etc. In this paper, the methods fur calibration and for evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor are newly proposed. Also, a six-axis force/moment sensor is calibrated with the proposed calibration method and the relative expanded uncertainty is evaluated using the proposed uncertainty evaluation method and the calibration results. It is thought that the methods fur calibration and evaluation of the uncertainty can be usually used for calibration and evaluation of the uncertainty of the multi-axis force/moment sensor.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.114-121
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• 2017

This paper describes the design and fabrication of a three-axis force sensor with parallel plate beams (PPSs) for measuring the calf force while a patient with a walking assist robot is walking. Current walking assist robots can't measure the weight of the patient's leg and the robot's leg which required for robot control. So, the three-axis force sensor in the calf link is designed and manufactured, it is composed of a Fx force sensor, a Fy force sensor and a Fz force sensor. The three-axis force sensor was designed using by FEM(Finite Element Method), and fabricated using strain-gages. The characteristics experiment of the three-axis force sensor was carried out respectively. The test results indicated that the repeatability error and the non-linearity error of three-axis force sensor was less than 0.04% respectively. Therefore, the fabricated three-axis force sensor in the calf link can be used to measure the patient's calf force in the walking assist robot.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.229-232
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• 2002

This paper describes the development of robot's finger 3-axis force sensor that detects the Fx, Fy, and Fz simultaneously fur stably grasping an unknown object. In order to safely grasp an unknown object using the robot's fingers, they should detect the force of gripping direction and the force of gravity direction, and perform the force control using the detected farces. The 3-axis force sensor that detects the Fx, Fy, and Fz simultaneously should be used for accurately detecting the weight of an unknown object of gravity direction. Thus, in this paper, robot's finger for stably grasping an unknown object is developed. And, the 3-axis farce sensor that detects the Fx, Fy, and Fz simultaneously fur constructing a robot's finger is newly modeled using several parallel-plate beams, and is fabricated. Also, it is calibrated, and evaluated.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.211-219
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• 2007

This paper describes the development of 6-axis force/moment sensor for a humanoid robot. In order to walk on uneven terrain safely, the robot's foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself, and be controlled by the foot using the forces and moments. Also, in order to grasp unknown object safely, the robot's hand should perceive the weight of the object using the mounted 6-axis force/moment sensor to its wrist, and be controlled by the hand using the forces and moments. Therefore, 6-axis force/moment sensor should be necessary for a humanoid robot's hand and foot. In this paper, 6-axis force/moment sensor for a humanoid robot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing element of the sensor was designed using theoretical analysis. Then, 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from theoretical analysis agree well with the results from the experiments.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.105-113
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• 2003

This paper describes the development of a 6-axis robot's finger force/moment sensor, which measures forces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously, for stably grasping an unknown object. In order to safely grasp an unknown object using the robot's gripper, it should measure the force in the gripping direction and the force in the gravity direction, and perform the force control using the measured forces. Thus, the robot's gripper should be composed of 6-axis robot's finger force/moment sensor that can measure forces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously. In this paper, the 6-axis robot's finger force/moment sensor for measuring forces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously was newly modeled using several parallel-plate beams, designed, and fabricated. The characteristic test of made sensor was performed. and the result shows that interference errors of the developed sensor are less than 3%. Also, Robot's gripper with the 6-axis robot's finger force/moment sensor for the characteristic test of force control was manufactured, and the characteristic test for grasping an unknown object was performed using it. The fabricated gripper could grasp an unknown object stably. Thus, the developed 6-axis robot's finger force/moment sensor may be used for robot's gripper.