• Title, Summary, Keyword: Force

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Evaluation of Global Force and Interaction Body Force Density in Permanent Magnet Employing Virtual Air-gap Concept (가상공극개념을 이용한 연구자석의 전체전자기력과 상호체적력밀도 계산)

  • Lee, Se-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.278-284
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    • 2009
  • The global force and interaction body force density were evaluated in permanent magnets by using the virtual air-gap scheme incorporating the finite-element method. Until now, the virtual air-gap concept has been successfully applied to calculate a contact force and a body force density in soft magnetic materials. These force calculating methods have been called as generalized methods such as the generalized magnetic charge force density method, the generalized magnetizing current force density method, and the generalized Kelvin force density method. For permanent magnets, however, there have been few research works on a contact force and a force density field. Unlike the conventional force calculating methods resulting in surface force densities, the generalized methods are novel methods of evaluating body force density. These generalized methods yield the actual total force, but their distributions have an irregularity, which seems to be random distributions of body force density. Inside permanent magnets, however, a smooth pattern was obtained in the interaction body force density, which represents the interacting force field among magnetic materials. To evaluate the interaction body force density, the intrinsic force density should be withdrawn from the total force density. Several analysis models with permanent magnets were tested to verify the proposed methods evaluating the interaction body force density and the contact force, in which the permanent magnet contacts with a soft magnetic material.

A Mechanistic Model for 3 Dimensional Cutting Force Prediction Considering Ploughing Force in Face Milling (정면밀링가공에서 쟁기력을 고려한 3차원 절삭력 모델링)

  • 권원태;김기대
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.2
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    • pp.1-8
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    • 2002
  • Cutting force is obtained as a sum of chip removing force and ploughing force. Chip removing force is estimated by multiplying specific cutting pressure by cutting area. Since ploughing force is caused from dullness of a tool, its magnitude is constant if depth of cut is bigger than a certain value. Using the linearity of chip removing force to cutting area and the constancy of ploughing force regardless of depth of cut which is over a certain limit each force is separated from measured cutting force and used to establish cutting force model. New rotation matrix to convert the measured cutting force in reference axes into the forces in cutter axes is obtained by considering that tool angles are projected angles from cutter axes to reference axes.. Spindle tilt is also considered far the model. The predicted cutting force estimated from the model is in good agreement with the measured force.

Design of a Three-Axis Force Sensor for Finger Force Measuring System (손가락 힘측정장치의 3축 힘센서 설계)

  • Lee, Kyeong-Jun;Kim, Gab-Soon
    • 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%.

Detent Force Reduction in a Cylindrical Type PMLSM (원통형 영구자석 선형 동기전동기의 디텐트력 저감)

  • Lee, Jong-Jin;Youn, Sung-Whan;Koh, Chang-Seop
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.4
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    • pp.209-215
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    • 2006
  • Recently Permanent Magnet Linear Synchronous Motors(PMLSMs) are widely used for many linear transportation applications. The PMLSM has many advantages such as simple structure, high speed and thrust. However, especially in short primary type PMLSM, there exists very large detent force, which makes the thrust force ripple, undesired vibration and noise. The detent force is composed of the Cogging force and the End force. The Cogging force comes from the interaction between the permanent magnets and interior teeth of the stator. And the End force acts on the exterior teeth of the stator by the permanent magnets. Usually End force is larger than Cogging force, so the detent force is drasically reduced only by reducing the End force. This paper shows the End force is minimized by optimizing the stator length and chamfering the shape of the exterior teeth of the stator.

Development of a Force Measurement and Communication System for the Force Measuring System in Industrial Robots (산업용 로봇의 힘측정 시스템을 위한 힘측정 및 통신장치 개발)

  • Lee, Kyeong-Jun;Kim, Gab-Soon
    • 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.

Cutting Force Estimation Considering the Specific Cutting Force Constant (비절삭 저항상수에 따른 절삭력 예측)

  • Kim, Jong-Do;Yoon, Moon-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.10
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    • pp.75-82
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    • 2019
  • Few studies have been conducted regarding theoretical turning force modelling while considering cutting constant. In this paper, a new cutting force modelling technique was suggested which considers the specific cutting force coefficients for turning. The specific cutting force is the multiplication of the cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical cutting force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of three theoretical cutting forces for turning. The cutting force mechanism was verified in this research and its results were compared with each of the experimental and theoretical forces. The deviation of force was incurred by a small amount in this model and the predicted force considering feed rate, nose radius, and radial depth shows a physical behavior in main force, normal force, and feeding force, respectively. Therefore, this modelling technique can be used to effectively predict three turning forces with different tool geometries considering cutting force coefficients.

Cutting Force Modelling in End-milling Considering Runout (런아웃을 고려한 엔드밀링의 절삭력 모델링)

  • Cho, Hee-Geon;Kim, Jong-Do;Yoon, Moon-Chul
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.20 no.3
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    • pp.225-231
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    • 2011
  • In this paper, a new end-milling force modelling technique was suggested by considering runout, and its result was compared with real measured force. The specific cutting force is the multiplication of cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of theoretical force. The mechanism of end-milling force with runout was developed in this research and its result was verified by comparing the fluctuating theoretical force and its measured one. The fluctuation of force was incurred by a geometric shape of workpiece and its runout in holding. The result of suggested force considering runout shows a good consistency with measured one. So this modelling method can be used effectively for a prediction of end-milling force with runout effect.

A study of biting force in long face and normal face adults (Long face와 Normal face인 성인에서의 교합력에 관한 연구)

  • Yoo, Tai-Jyung;Sohn, Byung-Wha
    • The korean journal of orthodontics
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    • v.20 no.3
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    • pp.541-552
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    • 1990
  • Until now it has not surely been pointed out about the relation between the biting force and the facial types in scientific view. But it's correlation was assumed by several scientists : recently some literatures reported about the maximum biting force and facial types, but there's only a little articles about the relation between the biting force(biting force contain maximum biting force, chewing force and swallowing force) and facial type. So this study was, firstly, performed to establish the relation of the nomal face and long face versus biting force. 2ndly it was performed to establish the relation between the difference in mouth opening degrees versus biting force. 3rdly it was performed to establish the relation between male and female versus biting force. Biting force was measured from 56 adults (normal 26, long 30) whose samples was selected from Yonsei university students and Hospital patients. Sample was divided into 2groups (normal and long) by lateral cephalogram. The results of this study was obtained as follows. 1. Maximum biting force and chewing force in long face was smaller than normal face. 2. When the thickness of transducer was changed from 6m to 9mm, maximum biting force andchewingforcewaslargerthanbefore. 3. In case of comparing with male and female, male was larger than female in maximum biting force and chewing force.

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Design of Force Sensors for the Ankle Rehabilitation Robot of Severe Stroke Patients (중증뇌졸중환자의 발목재활로봇을 위한 힘센서 설계)

  • Kim, Han-Sol;Kim, Gab-Soon
    • 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.

Development of Force Measuring System using Three-axis Force Sensor for Measuring Two-finger Force (3축 힘센서를 이용한 두 손가락 힘측정장치 개발)

  • Kim, Hyeon-Min;Yoon, Jong-Won;Shin, Hee-Suk;Kim, Gab-Soon
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.9
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    • pp.876-882
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    • 2010
  • Stroke patients can't use their hands because of the paralysis their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by measuring the pressing force to be contacted with two fingers (thumb and first finger, thumb and middle finger, thumb and ring finger, thumb and little finger). But, at present, the grasping finger force of two-finger can't be accurately measured, because there is not a proper finger-force measuring system. Therefore, doctors can't correctly judge the rehabilitating extent. So, the finger-force measuring system which can measure the grasping force of two-finger must be developed. In this paper, the finger-force measuring system with a three-axis force sensor which can measure the pressing force was developed. The three-axis force sensor was designed and fabricated, and the force measuring device was designed and manufactured using DSP (Digital Signal Processing). Also, the grasping force test of men was performed using the developed finger-force measuring system, it was confirmed that the grasping forces of men were different according to grasping methods.