• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.393-397
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• 1996

A stewart platform-based force/torque sensor with 6 elastic legs was designed and manufactured Kinematic design parameters were determined so that the force/torque sensor might have the isotropic force/torque properities. In a force/torque analysis, it was used the solution of forward kinematics by linearization of the solution of the inverse kinematics. The performance of te force/torque sensor was investigated by measurement experiments. The gravity compensation was conducted to reduce the force and torque effects by the weights of the upper plate, joints and other sensor parts.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.339-342
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• 1996

In this paper, the method for controlling PUMA robot using F/T sensor is described. In the part of the setup automation, robot is used. The F/T sensor is located at robot end-effector and various experiments are executed such as peg in hole, gripping objects, tool changing, etc.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.218-222
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• 2011

This paper proposes a single-joint optical torque sensor with one body structure. Conventional optical torque sensors consist of three parts, two plates and an elastic structure. They have slightly slipping problem between plates and elastic structure due to the manufacturing tolerance. Since the order of measurement range of optical sensor is about ten micrometers, the slipping problem causes large measurement error, especially in the case of vibrational or high speed plant. This problem does not occur in the proposed design due to the one body structure. The proposed sensor has advantage of low cost, light weight, and small size. And it is easy to design and manufacture. Simulation works that analysis of stress and strain are performed accurately. To demonstrate the performance of proposed sensor, experiments were implemented to compare with a commercial force/torque sensor (ATI Mini45).

• 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.

• Journal of Magnetics
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• v.17 no.4
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• pp.285-290
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• 2012

Electric Power Steering (EPS) system is superior to conventional Hydraulic Power Steering (HPS) system in aspect of fuel economy and environmental concerns. The EPS system consists of torque sensor, electric motor, ECU (Electric Control Unit), gears and etc. Among the elements, the torque sensor is one of the core technologies of which output signal is used for main input of EPS controller. Usually, the torque sensor has used torsion bar to transform torsion angle into torque and needs linear characteristic in terms of flux variation with respect to rotation angle of permanent magnet. The torsion angle of both ends of a torsion bar is measured by a contact variable resistor. In this paper, the sensor is accurately analyzed using 3D finite element method and its characteristics with respect to four different shapes of the stator teeth are compared. The four shapes are rectangular, triangular, trapezoidal and circular type.

• Tribology and Lubricants
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• v.28 no.3
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• pp.130-135
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• 2012

This study presents a new methodology for realtime tool breakage detection by sensor fusion concept of two hall sensor and an acoustic emission (AE) sensor. Spindle induction motor torque of CNC Lathe during machining is estimated by two hall sensor. Estimated motor torque instead of a tool dynamometer was used to measure the cutting torque and tool breakage detection. A burst of AE signal was used as a triggering signal to inspect the cutting torque. A significant drop of cutting torque was utilized to detect tool breakage. The algorithm was implemented on a NI DAQ (Data Acquisition) board for in-process tool breakage detection. The result of experiment showed an excellent monitoring capability of the proposed tool breakage detection system. This system is available tool breakage monitoring through internet also provides this system's user with current cutting torque of induction motor.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.8
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• pp.570-578
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• 1988

In order for a robot to carry out a precise assembly task with compliant motion, a force/torque sensor is needed. The output of the cross-bar structured force / torque sensor which is used in a peg-in-hole insertion task and attached to a SCARA type robot, is analzed. First, the relationship between the sensor outputs and the force / torque components obtained by the outputs is investigated. Second, in a peg-in-hole insertion task, the sensor outputs changing with the contact position of the peg and the hole, are analyzed. Also, the relative position of the peg and the hole is obtained from the sensor outputs. The peg-in-hole insertion task is successfully executed, using a SCARA type robot with a wrist force / torque sensor manufactured in our laboratory and the compliance algorithm from the results of this paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.133-138
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• 2016

Force control and collision detection for a robot are usually conducted using a 6-axis force/torque sensor mounted at the end-effector. However, this scheme suffers from high-cost and the inability to detect collisions at the robot body. As an alternative, joint torque sensors embedded in each joint were used, which also suffered from various errors in torque measurement. To resolve this problem, a robot joint module with an improved joint torque sensor is proposed in this study. In the proposed torque sensor, a cross-roller bearing and disk-type coupling are added to prevent the moment load from adversely affecting the measurement of the joint torque under consideration. This joint design also aims to reduce the stress induced during the assembly process of the sensor. The performance of the proposed joint torque sensor was verified through various experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1061-1062
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• 2011