• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1097-1100
• /
• 2003

Data Loggers for environmental monitoring are mostly dispersion in installation and systems located at long distance from monitoring system. And, it requests mostly flexible functions and high performances. that can fit to various sensor inputs, sensor interfaces and conditions or system working. In this research, we developed the micro controller based Data Logger with minimum hardware construction that allows the higher flexibility of application. Finally, we developed software function for water quality monitoring and tested in real system launched at Han river.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.2
• /
• pp.135-138
• /
• 2011

Although most of control methods have been studied in the continuous-time domain, the actual control systems have been implemented using MCU (Micro Control Unit) and/or microprocessors so that the overall systems turn to be sampled-data systems. In this case, the stability criterion of the closed-loop system is not easy to derive. In this paper, a simple stability criterion for the sampled-data system with sliding mode controller is derived.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.118.4-118
• /
• 2001

An Inspection system, composed of sensor head and controller, is presented which is a 3-D laser vision system using principles of optical triangulation for weld quality and chamfer quality. The sensor head id composed of laser diode, micro CCD camera, filter and several optical components. This systems can be used in welding bead and undercut inspection and chamfer quality inspection as well. It is mech more convenient to use and the inspection time is to be greatly shortened compared with conventional inspection method. Furthermore, data saved in controller can be used for statistics afterwards. This system has been begin used in Koje Shipyard of Samsung Heavy Industries and the need is being increased.

• The Magazine of the IEIE
• /
• v.29 no.1
• /
• pp.66-72
• /
• 2002

VLSI 기술의 발전은 보다 많은 양의 로직을 단일 칩에 집적 가능하게 했고, 이는 System-on-a-chip 시대의 도래를 가능하게 했다. System-on-a-chip을 가능하게 하기 위해서는 많은 종류의 IP (Intellectual Property)가 필요하고, 공정 변환을 쉽게 하기 위해서는 합성이 가능한 RTL 설계가 절실히 요구된다. 본 논문은 이러한 요구에 부응하기 위해서 hard macro 형태의 기존의 IP로 부터 합성 가능한 IP를 자동 생성해 주는 ART(Automatic RTL Translation)로 명명된 기법에 관한 것이다. 제안된 ART 기법을 이용하여 80C52 호환의 8-bit MCU(Micro-controller Unit)의 합성 가능한 RTL model을 자동 생성하였고, 개발된 Soft IP를 이용하여 TCP/IP 전용 MCU를 표함해서 다양한 제품들을 개발하였다.

• Advances in nano research
• /
• v.9 no.3
• /
• pp.133-145
• /
• 2020

In this study, nonlinear vibrations and dynamic instabilities of a smart embedded micro shell conveying varied fluid flow and subjected to the combined electro-thermo-mechanical loadings are investigated. With the aim of designing new hydraulic sensors and actuators, the piezoelectric materials are employed for the body and the effects of applying electric field on the stability of the system as well as the induced voltage due to the dynamic behavior of the system are studied. The nonlocal piezoelasticity theory and the nonlinear cylindrical shell model in conjunction with the energy approach are utilized to mathematically modeling of the structure. The fluid flow is assumed to be isentropic, incompressible and fully develop, and for more generality of the problem both steady and time dependent flow regimes are considered. The mathematical modeling of fluid flow is also carried out based on a scalar potential function, time mean Navier-Stokes equations and the theory of slip boundary condition. Employing the modified Lagrange equations for open systems, the nonlinear coupled governing equations of motion are achieved and solved via the state space problem; forth order numerical integration and Bolotin's method. In the numerical results, a comprehensive discussion is made on the dynamical instabilities of the system (such as divergence, flutter and parametric resonance). We found that applying positive electric potential field will improve the stability of the system as an actuator or vibration amplitude controller in the micro electro mechanical systems.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.5
• /
• pp.792-799
• /
• 2017

The real time unmanned monitoring system of an equipment's internal parts and condition requires the monitoring device to be able to stop at a set location on the rail. However, due to the slip between the driving surface and the roller, an error occurs between the actual position and the command position. In this paper, a method to compensate the position error due to the roller slip is proposed. A proximity sensor located at both ends of the rail detects the starting point and the maximum position pulse, linearly compensating the error between the angular position of the motor and the mechanically fixed starting and maximum position pulse of the rail in forward and reverse direction. Moreover, unlike the existing servo position controller, the motor adopts the position detection method of Hall sensor in BLDC (Brushless DC) and applies an algorithm for low-speed driving so that a stable position control is possible. The proposed rail guided unmanned monitoring system with driving slip compensator was tested to verify the effectiveness.

• Smart Structures and Systems
• /
• v.6 no.1
• /
• pp.1-16
• /
• 2010

This paper presents a novel smart MEMS accelerometer which employs a hybrid control algorithm and an estimator. This scheme is realized by adding a sliding-mode controller to a conventional PID closed loop system to achieve higher stability and higher dynamic range and to prevent pull-in phenomena by preventing finger displacement from passing a maximum preset value as well as adding an adaptive nonlinear observer to a conventional PID closed loop system. This estimator is used for online estimation of the parameter variations for MEMS accelerometers and gives the capability of self testing to the system. The analysis of convergence and resolution show that while the proposed control scheme satisfies these criteria it also keeps resolution performance better than what is normally obtained in conventional PID controllers. The performance of the proposed hybrid controller investigated here is validated by computer simulation.

• Journal of Aerospace System Engineering
• /
• v.10 no.1
• /
• pp.86-94
• /
• 2016

In this paper, position control of focal plane compensation device using piezoelectric actuator is conducted. The forcal plane compensation device installed on earth observation satellite camera compensates micro-vibration from reaction wheels. In this study, four experimental models of the open-loop compensation device are derived using MATLAB system identification toolbox in the input range of 0~50Hz. Subsequently, the PID controller for each model is designed and the performance test of each controller is conducted through MATLAB/Simulink. According to frequency response analysis of the closed-loop compensation device system, the PID controller designed for 38~50Hz input range has enough tracking performance for the whole 0~50Hz input range. The maximum output error is about $1{\mu}m$ for the input range. The simulation results has been verified by the experimental method.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.3
• /
• pp.173-183
• /
• 1998

In this paper, an auto-tuning method for fuzzy controller's membership functions based on the neural network is presented. The neural network emulator offers the path which reforms the fuzzy controller's membership functions and fuzzy rule, and the reformed fuzzy controller uses for speed control of induction motor. Thus, in the case of motor parameter variation, the proposed method is superior to a conventional method in the respect of operation time and system performance. 32bit micro-processor DSP(TMS320C31) is used to achieve the high speed calculation of the space voltage vector PWM and to build the self-learning fuzzy control algorithm. Through computer simulation and experimental results, it is confirmed that the proposed method can provide more improved control performance than that PI controller and conventional fuzzy controller.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.8
• /
• pp.65-72
• /
• 2004

For the burrs formed in machining are irregular and very sharp in shape, it is usually very difficult to measure burr accurately. It was proved that micro burr geometry can be measured imprecision by the Conoprobe sensor using conoscopic holography method. We developed 3D burr measurement system using this sensor. The system is composed of Conoprobe sensor, XY table, controller and 3D measurement program. Some measurements using the developed system are conducted for the burrs formed in micro drilling and piercing. Specific software fur burr measurement includes several function, calculation of burr volume, average burr height. Burs formed on a curved surface were compensated and measured successfully using the basic surface compensation function.