• 제어로봇시스템학회논문지
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• 제6권4호
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• pp.327-332
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• 2000

In this paper, a new multi-fingered robot hand using ultrasonic motors and its control system are developed. The developed robot hand has four fingers and fifteen articulated joints. The distal joint of each finger is directly driven by ultrasonic motor and all joints except the distal joint has low transmission gear mechanism with the motor. The developed robot hand has several advantages in size compared to a hand using conventional DC motors, and in performance compared to a hand using tendons to drive joints. A VME-bus based hand control system and ultrasonic motor driver are also developed. The performance of the hand is confirmed by using the developed control system in real-time.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.593-596
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• 2008

The reed switch position transmitter (RSPT) is used as a position indicator for the control rod in commercial nuclear power plants made by ABB-CE. But this position indicator has some problems when directly adopting it to the integral reactor. The Control Element Drive Mechanism (CEDM) for the integral reactor is designed to raise and lower the control rod in steps of 2mm in order to satisfy the design features of the integral reactor which are the soluble boron free operation and the use of a nuclear heating for the reactor start-up. Therefore the resolution of the position indicator for the integral reactor should be achieved to sense the position of the control rod more precisely than that of the RSPT of the ABB-CE. This paper adopts seismic resistance reed switches to the position indicator in order to reduce the damages or impacts during the handling of the position indicator and earthquake.

• 드라이브 ㆍ 컨트롤
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• 제9권1호
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• pp.1-9
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• 2012

Nowadays, various researches about eco-friendly vehicles such as hybrid electric vehicle, fuel cell vehicle and electric vehicle have been actively carried out. Since most of these green cars have electric motors, the regenerative energy technology can be used to improve the fuel economy and the energy efficiency of vehicles. The regenerative brake is an energy recovery mechanism which slows a vehicle by converting its kinetic energy into electric energy, which can be either used immediately or stored until needed. This technology plays a significant role in achieving the high energy usage. However, there are some technical problems for controlling the regenerative braking and the electro-hydraulic brake during switching at transient region. In this paper, the performance simulator for fuel-cell vehicle is developed and transient response characteristics of the regenerative braking system are analyzed in the various driving situations. And the hardware-in-the-loop simulation of electro-hydraulic brake is performed to validate the transient characteristics of the regenerative braking system for fuel-cell electric vehicle.

• 드라이브 ㆍ 컨트롤
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• 제15권1호
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• pp.10-15
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• 2018

The hydraulic cylinder seals are used not only to protect leakage of the working fluids but also to prevent incoming of foreign particles into the system. Chromium plating is generally applied to improve corrosion and wear resistance. It has been noticed that sealing surface damage occurs due to the hard foreign/wear particles contained in the hydraulic oil. In this study, a three-bodied sliding contact problem related with a PTFE seal, a spherical particle and chrome-plated steel substrate is modeled to investigate the relations to wear mechanism. Using the nonlinear finite element software, MARC/MENTAT, the deformed shapes, the von Mises and first principal stress distributions with plating thickness were compared. The sealing surface was mainly abraded by hard particles embedded in the seal. The plastic deformation of the steel substrate decreased with thicker plating. Hence it could be more effective to coat the sealing surface of a hydraulic cylinder with a hard material such as TiN, TiC and DLC.

• Agricultural and Biosystems Engineering
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• 제1권2호
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• pp.100-105
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• 2000

Quality sorting of cut flowers is very essential to increase the value of products. There are many factors that determine the quality of cut flowers such as length, thickness, and straightness of stem, and color and maturity of bud. Among these factors, the straightness of stem and the maturity of bud are generally considered to be more difficult to evaluate. A prototype grading and sorting machine for cut flowers was developed and tested for a rose variety. The machine consisted of a chain-drive feed mechanism, a pneumatic discharge system, and a grading system utilizing color image processing and neural network. Artificial neural network algorithm was utilized to grade cut roses based on the straightness of stem and maturity of bud. Test results showed 89% agreement with human expert for the straightness of stem and 90% agreement for the maturity of bud. Average processing time for evaluating straightness of the stem and maturity of the bud were 1.01 and 0.44 second, respectively. Application of neural network eliminated difficulties in determining criteria of each grade category while maintaining similar level of classification error.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.453-458
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• 2011

Air preheater uses the waste heat of the gas which burnt from the boiler from the thermal power plant. Air preheater it is established in the exit of the boiler follows in change of temperature combustion gas and the vibration which it follows in thermal expansion and contraction occurs. Air preheater with ruse the gas the seal the place where it includes a gap in the structure which it does, the vibration which it follows in change of temperature fluctuates the displacement of gap, fluctuation of the leakage quantity which occurs from gap there is a possibility of decreasing an effect to system. Part system it will be able to control the interval of gap in order, control mechanism about under establishing the place where it does the gap control actively, measures a gap the displacement sensor for is necessary. Like this displacement sensor the condition must do continuous running from atmosphere of high temperature was demanded all. This paper investigates the implementation instance of hazard existing which implement the high temperature displacement sensor, it analyzes, produces the result which it examines a model, it was a presentation. These results with the fact that it will contribute in the research for the implementation and a localization of the high temperature displacement sensor and advanced air preheater.

• 한국생산제조학회지
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• 제25권6호
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• pp.410-420
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• 2016

The geometric dimension and shape of microchannels that are formed during surface texturing are widely studied for applications in flow control, and drag and friction reduction. In this research, a new method for controlling the deformation of U channels during micro-rolling-based surface texturing was developed. Since the width of the U channels is almost constant, controlling the depth is essential. A calibration procedure of initial rolling gap, and proportional-integral PI controllers and a linear interpolation have been applied simultaneously to control the depth. The PI controllers drive the position of the pre-U grooved roll as well as the rolling gap. The relationship between the channel depth and rolling gap is linearized to create a feedback signal in the depth control system. The depth of micro channels is studied on A2021 aluminum lamina surfaces. Overall, the experimental results demonstrated the feasibility of the method for controlling the depth of microchannels.

• 한국소음진동공학회논문집
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• 제16권1호
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• pp.75-80
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• 2006

This paper introduces the mechanism of the ESD(electrostatic discharge) in the HDD spindle system using FDBs(fluid dynamic bearings). When a HDD(hard disk drive) spindle system is rotating, triboelectric charging occurs in the FDBs through the friction between the lubricant and the rotating shaft or between the lubricant and stationary sleeve. And this electrostatic charge is accumulated in the rotating parts of the HDD spindle system because they are insulated from the ground by the lubricant. This research shows experimentally that the behavior of electric charge and discharge in the FDB spindle system is the same as that of a capacitor. It also measures the electrostatic voltage difference between the rotating and stationary parts in the FDB spindle system due to the change of humidity, supporting load and motor speed. This research shows that the control of ESD is required in the HDD spindle system using FDBs, because the electrostatic charge accumulated in the FDB spindle system may cause the breakdown damage of the GMR head and data loss consequently.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.672-675
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• 2006

It is becoming more significant to develop a rotary VCM type actuator for small form factor ODD, as portables are getting more and more popularized nowadays. In this paper, the procedure of development of the actuator which is applicable to compact flash II card and is fit in the specification of BD 1X is explained. This is based on the rotary VCM type actuator, which is good for reducing thickness. Air core solenoid coil is used in order to do focusing mechanism. And the total weight is reduced by using the structure of steel-aluminium-steel triple layer, so, the stiffness is still adequate. Additionally, the tracking coil is moved next to the actuator, so the total length was reduced, then the actuator become applicable to compact flash II card. The force of Magnetic Circuit is improved by using Magnetic Circuit DOE. And flexible mode frequency improved through the DOE of structure part. Modeling was exactly done in consideration of air core solenoid coil and pivot bearing. It is confirmed that the designed model is satisfied with the specification of BD 1X and is applicable to Compact Flash II card.

• 센서학회지
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• 제15권1호
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• pp.40-46
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• 2006

This paper presents a novel fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy cabling, and low cost. In this paper, a prototype of the fiber optic accelerometer system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. A unique algorithm has also been developed to derive the sensor's acceleration from the raw signals of the light control unit; it is implemented via a separate signal processing unit. Finally, the shaking table tests successfully demonstrate the performance and the potential of the moire fringe fiber optic sensor system to monitor the health of civil infrastructures.