• Tribology and Lubricants
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• v.15 no.3
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• pp.278-286
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• 1999

To predict the behavior of the intravascular micro active endoscope in the real human vascular system, a human mock circulation system was developed. The intravascular micro active endoscope which consists of micro active bending catheter and micro drug infusion catheter was driven in the velocity, Re number and temperature controlled flow. The three SMA (Shape Memory Alloy) zigzag type spring in the micro active bending catheter was heated by the electric current generated by PWM controller, and the shape memory effect made the actuator bend to any direction. The micro drug infusion catheter was driven through the inner hole of the micro active bending catheter. A mock circulation system is shaped from Ascending Arota to Femoral artery according to a human data (the data contains many vascular sizes and hydrographs of many control points). We developed a vascular model with glass and silicone tubes, and set the flow system with circulation parts, flow settling parts, and lots of valves. The heater and heat-controller was added to the How system to centre! the temperature of the How at 36.5$^{\circ}C$. The result showed that the developed intravascular micro active endoscope could be induced to any point in the vascular model.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.5
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• pp.44-53
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• 1993

In this paper, we discuss on the control algorithm to make the wheeled inverse pendulum type mobile robot move in two dimensional plane. The robot considered in this paper has two independently driven wheels in same axel which suport and move it-self, and is assumed to have the fyro type sensor to know the inclination algle of the body and rotary encoders to know wheel's rotation angular velocity. The control algorithm is divided into three parts. The first part is for the posture and velocity control for forward-backward direction, the second is the steering control, and the last part is for the control of total system to track the given trajectory. We handle the running velocity control of the robot as part of the posture control to keep the balance because the posture relates deeply with the velocity and can be controlled by the velocities of the wheels. The control problem is analyzed as the tracking control, and the controller is realized with the state feedback and feed-forward of the reference velocity. Constructing the control system which contained one intergrator in forward path, we also realized the control system without observer for the estimation of the accumulated errors in the inclination angle of the body. To prevent the robot from being unstable state by sudden variation of the reference velocity when it starts and stops, or changes velocity, the reference velocity of which acceleration is slowly changing, is ordered to the robot. To control its steering, we give the different reference velocities for both wheels which are calculated from the desired angular velocity of the body. Finally, we presents the experimental results of the experimental robot Yamabico Kurara in which the proposed control algorithm had been implemented.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.14-24
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• 2011

In order to facilitate the electricity market operation and trade in the restructured environment, ample transmission capability should be provided to satisfy the demand of increasing power transactions. The conflict of this requirement and the restrictions on the transmission expansion in the restructured electricity market has motivated the development of methodologies to enhance the available transfer capability (ATC) of existing transmission grids. The insertion of flexible AC transmission System (FACTS) devices in electrical systems seems to be a promising strategy to enhance single area ATC and multi-area ATC. In this paper, the viability and technical merits of boosting single area ATC and multi-area ATC using Thyristor controlled series compensator (TCSC), static VAR compensator (SVC) and unified power flow controller (UPFC) in single device and multi-type three similar and different device combinations are analyzed. Particle swarm optimization (PSO) algorithm is employed to obtain the optimal settings of FACTS devices. The installation cost is also calculated. The study has been carried out on IEEE 30 bus and IEEE 118 bus systems for the selected bilateral, multilateral and area wise transactions.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.10
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• pp.113-120
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• 2006

A cam profile CNC grinding machine is developed for manufacture of high precision contoured cams. The developed machine is composed of the high precision spindle using boll bearings, the high stiffness box layer type bed and the three axis CNC controller with the high resolution AC servo motor. In this paper, structural and modal analysis for the developed machine is carried out to check the design criteria of the machine. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. The machine is modeled by placing proper shell and solid finite elements. And also, this paper presents the measurement system and experimental investigation on the modal analysis of a grinding machine. The weak part of the machine is found by the experimental evaluation. The results provide structure modification data for good dynamic behaviors. And safety of the machine was confirmed by the modal analysis of modified machine design. Finally, the cam profile grinding machine was successfully developed.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1313-1320
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• 2013

An ultraprecision multi-axis machine tool has been designed and developed in our laboratory. The machine tool has four moving axes which are composed of three linear axes and one rotational axis. It has a gantry type structure and the Z-axis is on the X-axis and the C-axis, on which a workpiece is located, is inside the Y-axis. This paper shows control performance improving method and procedure for the ultra-precision positioning control of a hydrostatic bearing guided linear axis. Through improvements of electrical and mechanical components for the control system such as control electronics and oil pumping systems, the control disturbing noise is decreased. Also by the frequency domain analysis of control system those problem-making system components are identified and modified with analytical methods. The controller is analyzed and designed from frequency domain data and system information. In the experimental control results the nanometer order control result is successfully presented.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.316-323
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• 2004

This paper develops an ADWHM(Advanced Digital Watt-Hour Meter) which integrates and implements the voltage management data record function and the load management data record function in the electronic watt-hour meter. ADWHM is developed based on PIC16F874 which is 8bit micro-controller of RISK type for the easy of programing and maintenance, and electronic power signal processing module is located at front of it to reduce the computing load of processor. Also, a 16kbyte EEPROM is used to record the voltage management data and load management data for a week as well as watt-hour data and USART communication mode is used to transfer data from ADWHM to PC. The accuracy of the voltage and unt measuring for ADWHM is verified by identifying the LCD display values of the ADWHM after the voltage signals of id levels from digital function generator is applied to PT(Potential Transformer) and CT(Current Transformer) output under state which it is separated from real power line. On the its basic functions such as watt-hour data recording function, voltage management data recording function and load management data recording function was verified by showing data for three days among the collected data to PC by RS232C communication from ADWHM which was connected to real power lines for a week.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.69-77
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• 2020

This paper proposes an effective method of giving users feedback on 3-dimensional drawing and measures its performance to ensure that feedback can help users enter the correct position in 3D. In the experiment of drawing a given line shape using a hand-held controller, the user is provided with three levels of visual, auditory, and haptic feedback for the position input error. As a result of analyzing the position input accuracy according to the type of feedback, all types of feedback are able to significantly reduce errors, and visual feedback and haptic feedback are more effective than auditory feedback.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.565-569
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• 2004

The wing-body trucks are special vehicles that are designed to provide large carrying space and to protect the freights from outside impacts and bad weather. They are constructed to the structure opening and shutting three-layered aluminum top. In the middle- and large-size(above one-ton) wing-body trucks, wing-body is opened/closed by opening and shutting device of oil pressure type. But one-ton truck is constructed that its wing-body is opened/closed in manual to use helping of stay-dampers. So, we developed an electronic opening and shutting device for one-ton wing-body trucks to improve the inconvenience of usage for manually operated wing-body. The developed device is consisted of two connected links and a dc motor combined with an worm gear. The worm gear changes the rotation axis of the dc motor to a right-angled direction and transfers the torque of dc motor to the links. The two connected links open/shut the wing-body using the torque transferred from the dc motor. When the wing-body starts to be opened, the biggest torque is required from the dc motor for opening the wing-body. And as the wing-body is opened more and more, the required torque is smaller for opening the wing-body. Thus, the structure of two connected links are designed to locate at the center of worm gear so that maximum torque of the dc motor is transferred the links at the initial time starting to open wing-body. The controller of the device with open and closed buttons also is designed to protect the device from over-opening and over shutting operations. The developed device is accomplished for many experiments using actual vehicle. Those experiments show that the device has more excellent performance than the oil pressure type.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.4
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• pp.451-465
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• 2003

Statement of problem : Recently various implant components such as premachined gold cylinder, plastic cylinder gold UCLA abutment and plastic abutment were developed and used clinically without clinical investigation. Purpose : The purpose of this study was to evaluate the effects of fabrication of gold cylinder on the fitness and preload of the standard abutment and also the effects of fabrication of UCLA gold abutment on the fitness and stress transfer around the implant fixture. Material and method : Three kinds of gold cylinders such as, as-received gold cylinder (Nobel Biocare, Sweden), gold cylinder after casting, and plastic cylinder after casting with type IV gold alloy were tested over the top of the standard abutment. At the same time, three types of abutments such as, gold UCLA abutment before and after casting, and plastic abutment after casting were tested. The cylinder and abutment was secured over the fixture with conventional pre-load values using an electronic torque controller (Nobel Biocare, Sweden). The fitness of the abutment on the fixture and gold cylinder over the standard abutment were measured using the microhardness tester (MXT 70, Matsuzawa, Japan). Preload and the strain values were recorded using the strain balance unit (SB-10, Measurement group, Raleigh, USA) and strain indicator (P-3500, Measurement group, Raleigh, USA) systems. Results and conclusion : 1. Significant differences were found in the fit between the gold cylinder and plastic cylinder. 2 There were significant differences between the preload of the gold cylinder and that of the plastic cylinder. 3. Significant differences were found in the fit between the gold UCLA abutment and plastic UCLA abutment. 4. There were no significant differences in the stress generated on the supporting structure of the fixture among different cylinder and abutment groups.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.311-318
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• 2004

Generally, PM BLDC drive system is necessary that the three Hall-ICs evenly be distributed around the stator circumference and encoder installed in case of the 3 phase motor. The Hall-ICs are set up in this motor to detect the main flux from the rotor. So the output signal from Hall-ICs is used to drive a power transistor to control the stator winding current. Instead of using three Hall-ICs and encoder, this paper uses only two Hall-ICs for the permanent magnet rotor position and for the speed feedback signals, and uses a micro controller of 16-bit type(80C196KC) with the 3 phase PM BLDC whose six stator and two rotor designed. Two Hall-IC Hc and $H_B$ are placed on the endplate at 120 degree phase difference. With these elements, we estimate information of the other phase in sequence through a rotating rotor.