• 한국정밀공학회지
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• 제30권3호
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• pp.300-307
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• 2013

This paper describes the development of a cylindrical-object grasping force measuring system applied haptic technology to measure the grasping force of strokes patients' fingers and other patients' paralyzed fingers. Because the cylindrical-object and the force measuring device of the developed cylindrical-object grasping force measuring system are connected with the electrical wires, patients and their families have difficulty not only measuring the patients' grasping force using the system but also knowing their rehabilitation extent when using it. In this paper, the cylindrical-object grasping force measuring system applied haptic technology was developed, and the cylindrical-object grasping force measuring device sends data to the rehabilitation evaluating system applied haptic technology by wireless communication. The grasping force measurement characteristic test using the system was carried out, and it was confirmed that the rehabilitation extent of the patients' paralyzed fingers and normal people fingers can be evaluated.

• 제어로봇시스템학회논문지
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• 제22권7호
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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.

• 로봇학회논문지
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• 제13권1호
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• pp.55-62
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• 2018

In this paper, a method for estimation of external force on an end-effector using joint torque sensor is proposed. The method is based on portion of measure torque caused by external force. Due to noise in the torque measurement data from the torque sensor, a recursive least-square estimation algorithm is used to ensure a smoother estimation of the external force data. However it is inevitable to create a delay for the sensor to detect the external force. In order to reduce the delay, modified recursive least-square is proposed. The performance of the proposed estimation method is evaluated in an experiment on a developed six-degree-of-freedom robot. By using NI DAQ device and Labview, the robot control, data acquisition and The experimental results output are processed in real time. By using proposed modified RLS, the delay to estimate the external force with the RLS is reduced by 54.9%. As an experimental result, the difference of the actual external force and the estimated external force is 4.11% with an included angle of $5.04^{\circ}$ while in dynamic state. This result shows that this method allows joint torque sensors to be used instead of commonly used external sensory system such as F/T sensors.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.439-441
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• 2014

단층 $MoS_2$는 현재 트랜지스터나 LED등에 활용을 연구중인 물질이다. 단층 $MoS_2$의 밴드구조는 약 1.8eV의 직접 밴드갭을 보이는 반도체로 알려져있다. 이 물질을 소자에 활용할 때 고유의 1.8 eV 직접 밴드갭을 이용한다. 다양한 분야에 소자로 응용되기 위해서는 밴드갭을 조절이 필요하다. 그래서 $MoS_2$의 밴드갭을 조절하는 연구가 행해져 왔는데 그 중 하나가 수소흡착 방법이다. 수소를 단층 $MoS_2$에 흡착시키면 금속 밴드구조를 보인다고 알려져 있다. 본 연구에서는 DFT (Density Functional Theory) 계산을 통하여 밴드갭을 조절하는 다른 방법 중에 하나인 역학적인 힘에 의해 전기적인 특성의 변화에 대한 기초연구를 진행하였다. 단층 $MoS_2$에 in-plane 방향으로 isotropic strain을 주었을 때 밴드갭이 0.68 eV에서 1.89 eV까지 변하는 것을 확인했다. 우리는 단층 $MoS_2$는 약간의 strain에도 밴드갭크기가 다소 많이 변할 뿐만 아니라 직접 밴드갭이 간접 밴드갭으로 변하는 것을 보였다. 심지어 10%정도 strain을 주면 금속으로 변할 것으로 예상된다. 밴드갭이 변하는 성질을 이용하여 센서등 여러 어플리케이션에 단층 $MoS_2$를 활용할 수 있을 것으로 예상된다.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.8-17
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• 2010

In this paper, a fault tolerant control against sensor faults of electric parking brake (EPB) is proposed. Fault tolerant control method of EPB system is strongly demanded since sensor faults can endanger a driver's safety. In this paper, a clamp force estimation method is presented using motor's armature current and angular velocity. Clamp force estimation method is applied for fault detection method with parity equations. The goal of the detection method is to detect and identify faults in encoder, current sensor, force sensor, and parking cable. And a switching logic for fault tolerant control against the three sensor faults is suggested. Experimental results show that the proposed force estimation method satisfies the specifications of EPB system. The effectiveness of the fault detection method is validated with experimental results. Although a single sensor fault happens, EPB system with the proposed fault detection method does not develop into a failure on subsystem or system level.

• 한국산업융합학회 논문집
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• 제17권4호
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• pp.203-210
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• 2014

In this study, we present a method for correcting unbalanced sitting posture alignment to its optimal position, by designing a chair equipped with pressure sensor. With increasement in sedentary work, such as office work or study, people are now spending more time in chair. To accommodate sedentary life styles, many chairs are being designed for a comfortable sitting condition. However, without awareness and efforts for correct sitting posture, it may not be possible to achieve such condition. When the weight is not distributed evenly while sitting, it may cause various diseases such as scoliosis and a herniated disc. Being inspired by such facts, we have progressed basic researches to maintain the correct sitting posture. To demonstrate the proof-of-concept validation, we installed a series of sensors to a chair and then measured the changes in pressure distribution in various postures. The results show that this approach can be potentially helpful for understanding how fundamental problems due to unbalanced sitting posture can be corrected and maintained properly.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.368-373
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• 2003

This paper presents a study of low frequencies volume velocity vibration control of a smart panel in order to reduce sound transmission. A distributed piezoelectric quadratically shaped polyvinylidene fluoride (PVDF) polymer film is used as a uniform force actuator and an array of 4$\times$4 accelerometer is used as a volume velocity sensor for the implementation of a single-input single-output con rot system. The theoretical and experimental study of sensor-actuator frequency response function sho vs that this sensor-actuator arrangement provides a required strictly positive real frequency response function below about 900Hz. Direct velocity feedback could therefore be implemented with a limited gain which gives reductions of about 15㏈ in vibration level and about 8 ㏈ in acoustic power level at the (1, 1) mode of the smart Panel. It has been also shown that the shaping error of PVDF actuator could limit he stability and performance of the control system.

• 제어로봇시스템학회논문지
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• 제17권5호
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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.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 3부
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• pp.19-24
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• 2008

본 논문은 원격제어(teleoperation)시스템에서 카메라로부터의 실시간 영상정보를 이용하여 조작대상이 되는 물체의 물리기반모델(physically-based model)을 만들고 이를 기반으로한 햅틱 렌더링 알고리즘의 개발에 관한 것이다. CCD 카메라를 통한 영상정보와 물성치(mechanical properties)를 이용하여 변형체(deformable object)의 물리적 기반 모델이 구현되고 햅틱장치로 조종되는 평면 로봇(planar robot)을 제어하여 변형체에 변형을 가하면 구현된 물리적 모델에 의해 햅틱 피드백을 위한 반력값이 계산된다. 스네이크 알고리즘을 이 용하여 영상정보로부터 변형체의 외형정보(geometry information)를 추출하며, 변형체의 경계(boundary)에서의 반력값을 계산하기 위해 경계요소법(boundary element method)을 사용한다. 제안된 햅틱 렌더링 알고리즘을 이용하여 원격조작간에 힘센서를 사용하지 않고 사용자에게 햅틱 피드백을 제공할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.244-248
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• 1987

The force/torque sensor for robot is developed. The compliance algorithm for peg-in-hole insertion task using the forec/troque sensor is developed. The system consists of an IBM PC, robot, force/torque sensor, strain meter, A/D board, and interface board. The IBM PC functions as a main processor and the robot controller as a slave processor. The sensor is constructed to measure $T_x$, $T_y$, $F_z$ which are necessary to precisely execute a peg-in-hole insertion task by SCARA type assembly robot. The outputs of sensor are analyzed. On the basis of the analysis, compliance algorithm for peg-in-hole insertion task is developed. Some comments concerning the development of wrist force/torque sensor and compliance algorithm are given.