• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1147-1152
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• 2014

This paper describes the design of a four-axis force/torque sensor with PSPBs (Parallel Step Plate Beams). The sensor is composed of eight PSPBs, a force/torque transmitting block, and fixing blocks. It is designed by using the FEM(Finite Element Method), and fabricated by using strain gages. The characteristic tests of the sensor are carried out, and the interference error, repeatability error, and non-linearity error are less than 2.21%, 0.03% and 0.03%. Furthermore, the structure of the four-axis force/torque sensor with PSPBs has a larger rated capacity than that of the four-axis force/torque sensor with PPBs under the same overall sensor size and the same rated output. It is thought that the developed four-axis force/torque sensor with PSPBs can be used for measuring the forces and torques in an intelligent robot, automation devices, etc.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.118-123
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• 2013

Most serious stroke patients have the paralysis of their wrists, and can't use of their hands freely. But their wrists can be recovered by rehabilitation exercise. Recently, professional rehabilitation therapeutists exercise the wrists of stroke patients in hospital. But the wrists of stroke patients have not rehabilitated, because the therapeutists are much less than stroke patients in number. Therefore, the wrist bending-exercise rehabilitation robot that can measure the bending force of the patients' wrists is developed. In this paper, the three-axis force sensor was designed for the wrist bending-exercise rehabilitation robot. As a test results, the interference error of the three-axis force sensor was less than 0.85%. It is thought that the sensor can be used to measure the wrist bending force of the patient.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.484-489
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• 2011

Some patients can't use their hands because of inherent and acquired paralysis of their fingers. Their fingers can recover with rehabilitative training, and the extent of rehabilitation can be judged by grasping a cylindrical-object with their fingers. At present, the cylindrical-object used in hospitals is only a cylinder which cannot measure grasping force of the fingers. Therefore, doctors must judge the extent of rehabilitation by watching patients' fingers as they grasp the cylinder. A cylindrical-type finger force measuring system which can measure the grasping force of patients' fingers should be developed. This paper looks at the development of a cylindrical-type finger force measuring system with two-axis force/moment sensor which can measure grasping force. The two-axis force/moment sensor was designed and fabricated, and the high-speed force measuring device was designed and manufactured by using DSP (digital signal processing). Also, cylindrical-type finger force measuring system was developed using the developed two-axis force/moment sensor and the high-speed force measuring device, and the grasping force tests of men were performed using the developed system. The tests confirm that the average finger forces of right and left hands for men were about 186N and 172N respectively.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.27-36
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• 2007

This paper describes the development of 6-axis ankle force/moment sensor for the intelligent feet of a humanoid robot. When the robot walks on uneven terrain, the feet should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz from the attached 6-axis force/moment sensor on their ankles. Papers have already been published have some disadvantages in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis ankle force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to get the similar rated output under each rated load. Also, the size of the sensor is very important for mounting to robot's feet. Therefore, the diameter should be below 100 mm and the height should be below 40mm. In this paper, first, the structure of a 6-axis ankle force/moment sensor was modeled for a humanoid robot's feet newly, Second, the equations to predict the strains on the sensing elements was derived, third, the size of the sensing elements was designed by using the equations, then, the sensor was fabricated by attaching straingages on the sensing elements, finally, the characteristic test of the developed sensor was carried out. The rated outputs from the derived equations agree well with the results from the experiments. The interference error of the sensor is less than 2.94%.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.357-363
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• 2013

Most serious patients who have the paralysis of their ankles can't use of their feet freely. But their ankles can be recovered by an ankle bending rehabilitation exercise and a ankle rotating rehabilitation exercise. Recently, the professional rehabilitation therapeutists are much less than stroke patients in number. Therefore, the ankle-rehabilitation robot should be developed. The developed robot can be dangerous because it can't measure the applied bending force and twisting moment of the patients' ankles. In this paper, the six-axis force/moment sensor for the ankle-rehabilitation robot was specially designed the weight of foot and the applied force to foot in rehabilitation exercise. As a test results, the interference error of the six-axis force/moment sensor was less than 2.51%. It is thought that the sensor can be used to measure the bending force and twisting moment of the patients' ankles in rehabilitation exercise.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.91-98
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• 2007

This paper describes the development of the calibration system for a multi-axis force/moment sensor and its uncertainty evaluation. This calibration system can generate the continuous forces (${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$) and moments (${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$). Many kinds of multi-axis force/moment sensors in industries should be carried out the characteristic test or the calibration with the calibration system that can generate the forces and the moments. The calibration systems have been already developed are the disadvantages of the low capacity, the generation of step forces(10N, 20N ...) and step moments(1Nm, 2Nm ...) with weights, the high coasts in manufacture and so on. In this paper, the calibration system for a multi-axis force/moment sensor that can generate the continuous three forces and three moments was developed. Their ranges are $0{\sim}2000N$ in all force-directions and $0{\sim}400Nm$ in all moment-directions. And the system was evaluated in the expanded relative uncertainty. They were ${\pm}0.0004$ in all forces ${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$, and ${\pm}0.0004$ in all moments ${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$.

• Journal of Sensor Science and Technology
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• v.20 no.5
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• pp.351-356
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• 2011

Stroke patients should exercise for the rehabilitation of their fingers, because they can't use their hand and fingers. Their hand and fingers are fixed on the hand fixing system for rehabilitation exercise of them. But the hands clenched the fist of stroke patients are difficult to fix on it. In order to fix the hands and fingers, their palms are pressed with pressing bars and are controlled by reference force. The fixing system must have a five-axis force/moment sensor to force control. In this paper, the five-axis force/moment sensor was developed for the hand fixing system of finger-rehabilitation exercising system. The structure of the five-axis force/moment sensor was modeled, and designed using finite element method(FEM). And it was fabricated with strain-gages, then, its characteristic test was carried out. As a result, the maximum interference error is less than 2.43 %.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.152-158
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• 2022

As various mobile robots and manipulator robots have been commercialized, robots that can be used by individuals in their daily life have begun to appear. With the development of robots that support daily life, the interaction between robots and humans is becoming more important. Manipulator robots that support daily life must perform tasks such as pressing buttons or picking up objects safely. In many cases, this requires expensive multi-axis force/torque sensors to measure the interaction. In this study, we introduce a low-cost two-axis pressure sensor that can be applied to manipulators for education or research. The proposed system used three force sensitive resistor (FSR) sensors and the structure was fabricated by 3D printing. An experimental device using a load cell was constructed to measure the biaxial pressure. The manufactured prototype was able to distinguish the +-x-axis and the +-y-axis pressures.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.89-96
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• 2016

This paper describes the design of a force measurement and communication system for the force measuring system in industrial robots. The force measurement and communication system is composed of a multi-axis force sensor and a controller for measuring the forces (x-direction force, y-direction force and z-direction force) and sending the measured forces to the robot's controller (PLC: Programmable Logic Controller). In this paper, the force measurement and communication system was designed and fabricated by using a DSP (Digital Signal Processor). An environment test and a grinding and deburring test using an industrial robot with the force measurement and communication system with three-axis force sensor were carried out to characterize the system. The tests showed that the system could safely measure the forces from the three-axis force sensor and send the measured forces to the industrial robot's controller while the grinding and deburring test was performed. Thus, it is thought that the fabricated force measurement and communication system could be used for controlling the force for an industrial robot's grinding and deburring.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.2
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• pp.146-151
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• 2001

The importance of sensing the force and torque with arbitrary direction and magnitude is becoming more crucial for robotic applications and manufacturing automations. Recently, several designs of a multi-axis force-torque sensor have been tried to sense this force and torque. This paper deals mainly with the signal processing of a six-axis force-torque sensor using cross-shaped elastic structures with circular holes. In this paper, we show principle of sensing force and torque, the signal processing methodology, and efficient methods of seeking strain gage positions in the sensor structure. The validity of the proposed method is shown via experiments.