• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.148-154
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• 2016

This paper describes the design and fabrication of a two-axis force/torque sensor and an one-axis force sensor with parallel plate beams(PPSs) for measuring forces and torque in an ankle rehabilitation exercise using by a lower rehabilitation robot. The two-axis force/torque sensor is composed of a Fy force sensor and Tz torque sensor and the force sensor detects x direction force. The two-axis force/torque sensor and one-axis force sensor were designed using by FEM(Finite Element Method), and manufactured using strain-gages. The characteristics experiment of the two-axis force/torque sensor and one-axis force sensor were carried out respectively. As a test results, the interference error of the two-axis force/torque sensor was less than 1.56%, the repeatability error and the non-linearity of the two-axis force/torque sensor were less than 0.03% respectively, and the repeatability error and the non-linearity of the one-axis force sensor were less than 0.03% and 0.02% respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.524-529
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• 2016

We describe the design and fabrication of a two-axis force/torque sensor with parallel-plate beams (PPBs) and single beams for measuring force and torque in hip-joint rehabilitation exercise using a lower rehabilitation robot. The two-axis force/torque sensor is composed of an Fz force sensor and a Tz torque sensor, which detect z direction force and z direction torque, respectively. The two-axis force/torque sensor was designed using the FEM (Finite Element Method) and manufactured using strain gages. The characteristics experiment of the two-axis force/torque sensor was carried out. The test results show that the interference error of the two-axis force/torque sensor was less than 0.64% and the repeatability error and the non-linearity of the two-axis force/torque sensor were less than 0.03%. It is thought that the developed two-axis force/torque sensor could be used for a lower rehabilitation robot.

• 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 Sensor Science and Technology
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• v.24 no.2
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• pp.137-143
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• 2015

This paper describes the design of a two-axis force sensor with two step plate beams for measuring forces in an upper-limb rehabilitation robot. The two-axis force sensor is composed of a Fz force sensor and a Ty torque sensor. The Fz force sensor measures the force applied to a patient's arm pushed by a rehabilitation robot and the force of patient's arm. The Ty torque sensor measures the torque generated by a patient's arm motion in an emergency. The structure of sensor is composed of a force transmitting block, two step plate beams and two fixture blocks. The two-axis force sensor was designed using FEM (Finite Element Method), and manufactured using strain-gages. The characteristics test of the two-axis force sensor was carried out. as a test results, the interference error of the two-axis force sensor was less than 1.24%, the repeatability error of each sensor was less than 0.03%, and the non-linearity was less than 0.02%.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.469-476
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• 2005

Performance of a force-torque sensor is affected significantly by an error signal that is included in the sensor signal. The error sources may be classified mainly into two categories: one is a structural error due to inaccuracy of sensor body, and the other is a noise signal existing in sensed information. This paper presents a principle of 6-axis force-torque sensor briefly, a double-hole structure to be able to improve a structural error, and then a signal conditioning to reduce the effect of a noise signal. The validity of the proposed method is investigated through experimental study, which shows that SIN ratio is improved significantly in our experimental setup, and the sensor can be implemented cheaply with reasonable performance.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.835-839
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• 2004

For factory automation using force/torque control, we need a networked-force management system as well as good force sensing and force generation. In this paper, we present a web-based force management system including 6-axis force/torque sensing system. Performance of the force-torque sensor is affected significantly by analog noise that is included in a sensor signal, and the noise should be reduced appropriately to obtain an adequate performance of the sensor. Moreover, the sensor itself should be convenient to install to a real application system. It should be compact in size and also easy to wire in real situation. In this viewpoint, we developed usb-based compact sensor system which is well communicated using web between two computers that exist far away. Software is programmed using LabVIEW and CCS-C. PIC microcontrollers are used for implementing a compact hardware. The proposed system is verified through experimental works.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.5
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• pp.413-420
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• 2015

This paper describes the design of an elbow rehabilitation robot based on force measurement that enables a severe stroke patient confined to their bed to receive elbow rehabilitation exercises. The developed elbow rehabilitation robot was providewitha two-axis force/torque sensor which can detect force Fz and torque Tz, thereby allowing it to measure therotational force (Tz) exerted on the elbow and the signal force Fz which can be used as a safety device. The robot was designed and manufactured for severe stroke patients confined to bed, and the robot program was manufactured to perform flexibility elbow rehabilitation exercises. Asa result of the characteristics test of the developed rehabilitation robot, the device was safely operated while the elbow rehabilitation exercises were performed. Therefore, it is thought that the developed rehabilitation robot can be used for severe stroke patients.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.207-216
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• 1991

In the case that the robot manipulator should respond to the variance and uncertainty of the environment in performing preforming precision tasks, it is indispensable that the robot utilizes the various sensors for intrlligence. In this paper, the robot force control method is implemented with a force/torque sensor, two personal computers, and a PUMA 560 manipulator for performing the various application tadks. The hybrid position/force control method is used to control the force and position axis separately. An interface board is designed to read the force/torque sensor output into the computer. Since the two computers should exchange the information quickly, a common memory board is designed. Before the algorithms of application tasks are developed, the basic force commands must be supplied. Thus, the MOVE-UNTIL command is used at the discrete time instant and, the MOVE-COMPLY is used at the continuous time instant for receiving the force feedback information. Using the two basic force commands, three application algorithms are developed and implemented for edge-following, insertion, and grinding tasks.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1254-1258
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• 2003

One of the major factors that effect sensor performance is analog noise that added in a sensor signal such as voltage. In multi-axis force sensors, error sources may be classified mainly in two groups. One is structural error due to inaccuracy of sensor body. The other error source is noise signals existing in the sensed information. This paper presents a brief review about the principle of multi-axis force sensors, and then proposes a method that can reduce the effect of noise signal to sensor performance. The method is to convert analog voltage signal to digital numbers near sensor body and then to read these digital signals and conduct signal processing in the computer. By this way, we can eliminate a bad effect of electromagnetic wave emitted from computer and of 60 Hz noise emitted from AC source. The proposed method is investigated through experimental demonstration. The experimental results show that it improves S/N ratio of the sensor about 40 times in our experimental setup.