Hyeon-Min Kim

Development of Two-Finger Force Measuring System to Measure Two-Finger Gripping Force and Its Characteristic Evaluation

Finger 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). At present, most hospitals have used a thin plastic-plate for measuring the two-finger grasping force, and we can only judge that they can grasp the plate with their two-finger through it, because the plate can`t measure the two-finger grasping force. But, recently, the force measuring system for measuring two-finger grasping force was developed using three-axis force sensor, but it is very expensive, because it has a three-axis force sensor. In this paper, two-finger force measuring system with a one-axis force sensor which can measure two-finger grasping force was developed. The one-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 two-finger force measuring system, it was confirmed that the grasping forces of men were different according to grasping methods, and the system can be used for measuring two-finger grasping force.

Development of Force Measuring System using Three-axis Force Sensor for Measuring Two-finger Force

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.

Design of a wrist rotation rehabilitation robot

This paper describes the design of a wrist rotation rehabilitation robot based on force measurements for severe stroke patients lying in bed wards or at home which allows them to receive wrist rehabilitation exercise. The manufactured six-axis force/torque sensor which can detect three directional force Fx, Fy, Fz and three directional torque Tx, Ty, Tz, was attached to the developed rehabilitation robot and allows the rehabilitation robot to measure a rotational force (Tz) exerted on a wrist, the signal force Fx, Fy, Fz and torque Tx, Ty which in turn allows the device to be used safely. The robot was designed and manufactured for severe stroke patients lying in bed, and a robot program was manufactured to perform a wrist rotation flexibility rehabilitation exercise. The results of a characteristics test for the developed rehabilitation robot showed that it was safely operated while the wrist rotation flexibility rehabilitation exercise was performed. Therefore, it is thought that the developed rehabilitation robot can be safely used with severe stroke patients.

Judgment Method of the Rehabilitation Extent using a Spherical Type Digital Finger Force Measuring System

This paper presents the judgment method of the rehabilitation extent using a spherical type digital finger force measuring system (SDFFMS). Stroke patients can’t use their fingers because of the paralysis of their fingers, but they can recover with rehabilitative training. The SDFFMS has been already developed by Kim (Author of this paper), and the finger grasping forces of normal people and stroke patients could be measured using it. But the SDFFMS could be not used to judge the extent of their rehabilitation, because the judgment method using it is not yet developed. In this paper, the characteristics tests for the grasping forces of normal persons and stroke patients were performed using the SDFFMS, and the judgment method of the rehabilitation extent was developed using the results. The tests confirm that the rehabilitation extent of stroke patients could be judged using the developed judgment method.

Design of Smart Three-Axis Force Sensor

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 threeaxis 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.

Development of wrist bending rehabilitation robot

This paper describes the wrist bending rehabilitation robot using a four-axis force/moment sensor. The robot can be used to exercise the wrist bending rehabilitation for severe stroke patients lying in bed wards or at home. The manufactured four-axis force/moment sensor which can detect two directional force Fx, Fy and two directional moment Mx, My, was attached to the developed rehabilitation robot and allows the rehabilitation robot to measure a bending force (Fx) exerted on a wrist, the signal force Fy and moments Mx, My which in turn allows the device to be used safely. The results of a characteristics test for the developed rehabilitation robot showed that it was safely operated while the wrist bending flexibility rehabilitation exercise was performed. Therefore, it is thought that the developed rehabilitation robot can be safely used with severe stroke patients.

Design of a Force Applying System for a Smart-phone Curved Glass Molding System and Its Characteristic Test

Abstract: This paper describes the design of a force applying system for a smart phone curved glass molding system and its characteristic test. The force applying system is composed of a motor and gear, a rectilinear movement structure, a force sensor, an LVDT (Linear Variable Differential Transformer) sensor, an up and down moving block, and so on. The system precisely controls the applying force and time to the plane glass because the glass can be easily destroyed under applied force, and can be bent imperfectly. As a result of the characteristic test, the curved glass can be manufactured using this system, and the holding time under 0N force, the applying force to the plane glass, the time for applying from 0N to maximum force, and the holding time under maximum force at the manufacture feasible temperature 620℃ were found. Keywords: plane glass, curved glass, molding system, force applying system, force sensor, LVDT sensor, rectilinear movement structure I. 서론 현재 스마트폰은 음성, 문자, 이메일 등 많은 통신과 컴퓨터에서 할 수 있는 대부분의 업무를 수행할 수 있을 정도로 기능적인 측면에서 급성장하게 되었다. 그러나 외형에서는 대부분 얇은 육면체 평면이므로 뒷 주머니에 넣기 등 휴대하기 불편할 뿐만 아니라 전화할 때 스마트폰의 평면유리가 얼굴에 닿아 불쾌감을 느끼는 등 외형 디자인 측면에서 인체공학적이지 못했다. 이와 같은 문제점을 해결하기 위해서는 스마트폰 전체가 가로(종)방향으로 곡면을 가지든지 혹은 세로(횡)방향으로 곡면을 가져야 한다. 그러기 위해서는 앞면을 덮는 평면유리를 곡면을 가지도록 제작해야 한다. 종방향 혹은 횡방향으로 곡면을 가지는 스마트폰을 제작하기 위하여 국내외 스마트폰 전문제작업체에서는 휘어지는 액정화면의 개발에 성공하였다. 또한 스마트폰의 앞면에 부착하는 평면유리를 곡면을 가지도록 제작하는데 성공하였다. 그래서 모 스마트폰 제조회사에서는 종방향으로 곡면을 가지는 스마트폰을 최근에 판매 중에 있다. 그러나 현재 평면유리 제조공정은 두꺼운 평면유리를 곡면으로 기계가공하여 제작하는 방식으로 가공 중에 파괴되기 쉬워 가공성공률이 매우 낮다. 따라서 종방향 혹은 횡방향으로 곡면을 가지는 스마트폰을 대량생산하기 위해서는 앞면 평면유리를 쉽게 대량으로 제조하는 기술개발이 필요하다. 곡면유리는 평면유리를 성형 가능온도까지 가열한 후 힘을 가하여 구부리는 방법으로 제조가 가능하다. 이와 같이 유리를 성형해서 제조하는 대표적인 제품이 스마트폰 카메라 렌즈이고, 이것은 성형하고자 하는 렌즈의 형상과 같은 금형을 만들고, 그 속에 원통의 평면유리를 넣은 후, 챔버 안에서 히터를 이용하여 열을 직접 전도하거나 복사열로 전도하는 방식으로 유리 성형온도까지 가열한다. 그리고 공기압을 이용하여 금형에 압력을 가하여 렌즈를 성형한다[1-3]. 이와 같은 렌즈 성형시스템은 직경 10mm 정도의 소형렌즈를 성형할 수 있고, 스마트폰의 앞면 평면유리를 곡면으로 성형하지는 못한다. 그래서 스마트폰의 앞면 평면유리를 곡면으로 성형하기 위한 새로운 형태의 성형시스템을 설계하였다[4-11]. 곡면유리를 제조하는 성형시스템에서 매우 중요한 요소 중의 하나가 성형온도에서 금형에 힘 혹은 압력을 가하여 유리를 구부리는 가압장치이다. 현재 설계된 스마트폰 곡면유리 성형시스템의 가압장치는 공기압을 이용하여 유리의 파괴를 방지하기 위해 가압력을 여러 단계로 나누어 계단형식으로 설정된 압력까지 증가시키는 방식이다. 이 가압방식은 갑자기 큰 압력이 가해져 유리가 파손되기 쉽고 가압시간이 길어 생산성이* 저하되는 단점을 가지고 있다. 본 논문에서는 가압력을 힘으로 제어하여 스마트폰의 앞면 덮개유리를 곡면유리로 성형하는 곡면유리 성형시스템의 가압장치를 설계하였고, 특성실험을 통해 성형조건을 찾았다. 본 연구의 핵심부품인 가압력을 측정하는 힘센서를 설계 및 제작하였고, 힘을 측정하는 힘측정기를 설계 및 제작하였다. 그리고 힘측정장치가 포함되는 성형시스템의 가압시스템를

Development of Hand and Fingers Fixing System for Stroke Patient`s Rehabilitation Exercise

This paper describes development of a hand and finger fixing system for the rehabilitation exercise of patient`s fingers. In order to exercise the finger rehabilitation using a finger rehabilitation robot, a patient`s hand or fingers are fixed safely. In this paper, The hand and fingers fixing system can safely fix stroke patient`s hand and fingers by pressing with force control system. The characteristic test of the system was carried out. It is thought that the system could be used for fixing their fingers in stroke patient`s finger rehabilitation exercise.

Development of finger-force measuring system with three-axis force sensor for measuring a spherical-object grasping force

Stroke patients can`t use their hands because of the paralysis of their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by grasping a spherical object. At present, the object used in hospital is only a spherical object, and can`t measure the force of fingers. Therefore, doctors judge the rehabilitating extent by touching and watching at their fingers. So, the spherical object measuring system which can measure the force of their fingers should be developed. In this paper, the finger-force measuring system with a three-axis force sensor which can measure the spherical-object grasping force is developed. The three-axis force sensor is designed and fabricated, and the force measuring device is designed and manufactured using DSP(digital signal processing). Also, the grasping force test of men is performed using the developed finger-force measuring system, it was confirmed that the average force of men was about 120 N.