• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.257-268
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• 1990

A system has been developed for monitoring the effect of neuromuscular blocking frugs and the neuromuscular function during anesthesia and surgery. This system is composed of software and hardware, the latter are nerve stimulator, force transducer, interface board(preamplifier, filter, peripheral input/output) and personal computer (apple ll) , the former are programmed in ASSEMBLY and BASIC language. The nerve stimulator which is controlled by personal computer is capable of delivering single shocks at o.)Hz, train of four at 2Hz and tetanic stimulation at 30, 100, 200Hz. The response, adduction of the thumb, is sensed by the force transducer. The output of the force transducer Is amplified, filtered, converted digital signal and then processed by the per- sonal computer. The personal computer quantia4es twitch and traln of four tesponse and calculates the 74 ratio (Ta/Tl )between the first and fourth response of train of four. This ratio is used to estimate the level of the neuromuscular block. This system has reaserch potential for determining the effect of newer neuromuscular blocking drugs for comparlsion with presently used drugs of alternatively, for delerminig the effects of blocking drugs in altered physilogical states.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.165-171
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• 1998

An axial electromagnetic levitation system using attractive force is a highly nonlinear system due to the nonlinearity of materials, variable air gap and flux density. To control the levitating system with large air gap, a conventional PID control based on the linear model is not satisfactory to obtain the desired performance and the position tracking control of the sinusoidal motion by simulation results. Thus, sliding mode control(SMC) based on the input-output linearization is suggested and evaluated by simulation and experimental approaches. Usefulness of the SMC to this system is conformed experimentally. If the expected variation of added mass can be included in the gain conditions and the model, the position control performance of the electromagnetic levitation system with large air gap will be improved with robustness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2166-2180
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• 2016

We investigate the opposite of artificial noise (AN)-assisted communication in multiple-input-multiple-output (MIMO) wiretap channels for the multiuser case by taking the side of the eavesdropper. We first define a framework for an AN-assisted multiuser multiple-input-multiple-output (MU-MIMO) system, for which eavesdropping methods are proposed with and without knowledge of legitimate users' channel state information (CSI). The proposed method without CSI is based on a modified joint approximate diagonalization of eigen-matrices algorithm, which eliminates permutation indetermination and phase ambiguity, as well as the minimum description length algorithm, which blindly estimates the number of secret data sources. Simulation results show that both proposed methods can intercept information effectively. In addition, the proposed method without legitimate users' CSI performs well in terms of robustness and computational complexity.

• 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.

• Journal of Sensor Science and Technology
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• v.23 no.2
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• pp.127-133
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• 2014

This paper describes a design and manufacture of a two-axis force sensor and a single-axis force sensor for the fingers of an intelligent robot's hand. The robot's finger is composed of a two-axis force sensor, a first knuckle, a single-axis force sensor, a second knuckle, a spring, a motor of first knuckle, a motor of second knuckle, and so on. The two-axis force sensor attached to the first knuckle and the single-axis force sensor attached to the second knuckle were designed and manufactured, and the characteristics test of two sensors was carried out. As a test results, the interference error of the two-axis force sensor was less than 0.68%, the repeatability error of each sensor was less than 0.02%, and then the non-linearity was less than 0.03%. It is thought that the sensors can be used for the fingers of the intelligent robot's hand for rehabilitation exercise of finger patients.

• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.11-19
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• 2021

Linear variable differential transformer (LVDT) is a displacement sensor and is commonly used owing to its wide measurement range, excellent linearity, high sensitivity, and precision. To improve the output characteristics of LVDT, a few studies have been conducted to analyze the output using a theoretical method or a finite element method. However, the material properties of the core and the electromagnetic force acting on the core were not considered in the previous studies. In this study, a finite element analysis model was proposed considering the characteristics of the LVDT composed of coils, core, magnetic shell and electric circuit, and the core displacement. Using the proposed model, changes in sensitivity and linear region of LVDT according to changes in process and material parameters were analyzed. The outputs of the LVDT model were compared with those of the theoretical analysis, and then, the proposed analysis model was validated. When the electrical conductivity of the core was high and the relative magnetic permeability was low, the decrease in sensitivity was large. Additionally, an increase in the frequency of the power led to further decrease in sensitivity. The electromagnetic force applied on the core increased as the voltage increased, the frequency decreased, and the core displacement increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1262-1265
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• 2004

A cycloidal speed reducer is a type of the speed reducers of machinery. The cycloidal speed reducer consists of two cycloidal plate gears, housing roller gear, input shaft, output pin and shaft, and eccentric bearings. Especially the cycloidal plate gear has the peculiar parts of the teeth, because of gearing with the housing roller gear that has the several rollers on the circular line. And then all teeth on the cycloidal plate gear can be designed to contact with the rollers on the housing roller gear at the same time. Therefore the cycloidal plate gear has always contact motion with rollers and the force is interacted between roller gear with cycloidal plate gear. Because the contact force and friction force must be required to improve the accuracy in design procedures of cycloidal speed reducers, this paper presents a force analysis considered friction effect approach derived by static force equilibrium condition, geometrical adaptation, instant velocity center method and relative velocity method.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.64-75
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• 1993

In this study, the function of a hydraulic brake system with a vacuum booster is systematically analyzed according to the mutual relations which follow : - the brake pedal force vs. booster cylinder input force - the booster output force vs. master cylinder input force - the hydraulic line pressure vs. braking deceleration. A computer program is developed based on the theory which is able to predict and analyze the pedal force characteristics at the beginning of the initial stage of brake system design. Analytical results show good agreement with the experimental vehicle test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.411-415
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• 2002

In this paper, a mechanical probe for CMM (Coordinate Measuring Machine) with a three-axis force-sensing unit is proposed, which is capable of measuring an actual contact position without the lobbing effect and the pre-travel error. The force-sensing unit detects the external force, which is act on the stylus of CMM during the measuring process. Thus, the contact point of the stylus of CMM can be estimated ken the direction of measured force components. Based on the structural analysis of the proposed CMM probe, the transformation matrix is derived and calibrated so that it shows linear relationships between the estimated force components from the output voltages and the real input forces. And, the relationships are verified through the computer simulation. The results show that the proposed mechanical probe is very useful fur detecting the contacting force components on measuring process of CMM.