• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.26-33
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• 2017

We propose a variable frame structure connected with telescopic mast-shaped shaft for a robot displaying outstanding ability to cross obstacles, and for effective traction control. The wireless control system was built to extend and contract a deployable mechanism, which is shaped into a hoberman sphere assembled with frame structures. In order to develop important parameters for efficient locomotion, we derived an Euler-Lagrange equation for the spherical robot. According to the equation, the DC motor was selected. A prototype mechanism was tested and a Finite-Element Analysis (FEA) was conducted in parallel. Using these data, we constructed a deployable spherical robot with structural stability. The deployable robot moved at a speed of 0.85 m/s from 520 mm to 650 mm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.673-676
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• 2005

In this paper, we propose a improved control performance for autonomous mobile robot using the embeded system. The proposed PID(PPID) control method removes steady state error, and has good performance in transient response. The integral term in the proposed method accumulates error in increment section, inverses errors in decrement section, and increases the effect of integral coefficient around target. Therefore, the PPID control method decreases the overshoot, and makes settling time faster than general PID(GPID) control method. In order to verify the effectiveness of the proposed method(PPID), we simulated the position control of DC motor, and experimented the velocity control of autonomous mobile robot. The PPID control method demonstrated good control performance that decrease overshoot and settling time in simulation and experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.969-976
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• 2022

In this paper, a drunk driving prevention system was implemented to measure drunk driving before starting to prevent drunk driving accidents caused by complacency after drinking. In order to prevent a situation in which a driver but not a driver authenticates instead of a driver, the identification means was strengthened and the alcohol sensor was implemented to operate when the wind sensor measured above the set value set. Through this system, the driver's alcohol measurement process was strengthened. Sensors were determined through various experiments, and finally, when the alcohol concentration was 0.03% or more, the DC motor was stopped and the vehicle was designed to be unable to operate, thereby implementing a system in which drunk driving was prevented in advance.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.115-121
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• 2022

In surface mount technology (SMT), the screen printer, which is an equipment for applying solder cream, has a lot of poor coating as the pad becomes smaller. To solve this problem, a jet printer is being used recently. However, if the nozzle at the end of the valve applied to the jet printer head is not cleaned, solder cream remains or an error occurs. To prevent this, the nozzles should be cleaned periodically. In this paper, a more stable cleaning method than the existing technology is presented for the stable application of solder cream on a jet printer. In this method, cut a 35mm wide mujin cloth, wrap it in a roll, and rotate it with a DC geared motor on the other side to clean it. As a result, it was confirmed that the solder paste was not left on the nozzle surface and was well wiped when cleaning with about 2,000 dotting cycles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.88-95
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• 2006

PID controllers, which have been widely used in industry, have a simple structure and robustness to modeling error. But They we difficult to have uniformly good control performance in system parameters variation or different velocity command. In this paper, we propose a nonlinear adaptive PID controller based on a cell-mediated immune response and a gradient descent learning. This algorithm has a simple structure and robustness to system parameters variation. To verify performances of the proposed nonlinear adaptive PID controller, the speed control of nonlinear DC motor is performed. The simulation results show that the proposed control systems are effective in tracking a command velocity under system parameters variation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.495-501
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• 2013

In the present study, a BLDC motor for a pump in which a neodymium PM is replaced with a Ferrite PM has been developed in preparation for the cost increase and to ensure the stability of the resource supply. One of the currently used motors for pumps is a BLDC motor having an interior PM wherein a rare-earth PM is adopted. However, a BLDC motor for a pump is designed to have large airgap because of the use of a waterproof insulator according to its structural characteristics, and therefore, a SPM structure is suitable. Hence, an SPM BLDC motor in which a Ferrite PM is used is designed. Nevertheless, the use of Ferrite instead of rare-earth materials causes a deterioration in the performance of the electric motor, such as a decrease in the BEMF and the maximum power of the motor and the irreversible demagnetization of the PM. In order to mitigate such disadvantages, an optimized design of the BLDC motor is developed by changing each design parameter and by improving the electromagnetism structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.82-92
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• 2005

The present study was carried out in order to develop a remote-controlled micro ornithopter with a weight of 20 gram. This ornithopter has three channel radio control. It runs on two direct-current type pager motors powered by a lithium polymer battery which flaps its 35cm wings. The performance of an ornithopter, applied to a flapping motion only, was validated by flight tests. The flight test results indicate that the ornithopter developed here has sufficient thrust to propel itself.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1173-1179
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• 2007

In recent years, research to machine large-surface micro-features has become important because of the light guide panel of a large-scale liquid crystal display and the bipolar plate of a high-capacity proton exchange membrane fuel cell. In this study, in order to realize the systematic design technology and performance improvements of an ultra-precision machine for machining the large-surface micro-features, a structural characteristic analysis was performed using its virtual prototype. The prototype consisted of gantry-type frame, hydrostatic feed mechanisms, linear motors, brushless DC servo motor, counterbalance mechanism, and so on. The loop stiffness was estimated from the relative displacement between the tool post and C-axis table, which was caused by a cutting force. Especially, the causes of structural stiffness deterioration were identified through the structural deformation analysis of sub-models.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.2
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• pp.28-34
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• 1998

In this paper, I'd like to make a suggestion for boundary line detect algorithm which is used 3-D image processing system in order to track moving object. Through this study, more than anything else, difference image method was adopted to detect moving object in input image. To detect moving object, I made use of detect windows constructed by 4's predictive areas and object area for the purpose of reducing processing time and its size was determined by the size of moving object and prediction parameter directed center position. And also, tracking camera was movable toward the direction of X, Y by DC motor. As a conclusion of the study proposed algorithm, I found out the following results that tracking error was less than 6% of total moving object size and maximum tracking time 2 seconds by toy-car simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.1
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• pp.85-95
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• 1991

All physical systems are nonlinear to some degree. The examples are relay, backlash, deadzone, saturation element and so on. In the linear control system design, it is useful method to restrict the nonlinearity to the linearity of system over the operation range. It is worth noting that nonlinearities may be intentionally introduced in to a system. A simple of an intentional non-linearity is the Bang-Bang controller which uses the On-Off relay. In this paper, an angular position servosystem made of a DC servomotor controlled by a microcomputer is discribed. Authors use two methods in the design of controller. The one is linear controller designed by the optimal feedback control theory only and the other is nonlinear controller designed by On-Off relay with optimal feedback control theory. To do the real time control, the controller is designed by using 16bit personal computer and A/D.D/A converter(12bit) is used in order to convert the signal. According to this way, the results from real time control are as follows. 2) Under the On-Off controller with hysterisis the influence of disturbance is considerably smaller than the linerar controller. 3) An increase in the sampling period has a destabilizing effect. 4)In the controller performance, the response time of the On-Off controller is longer than that of the linear controller. To close, we note that the On-Off controller with hysterisis is more attractive than the linear controller in the presence of the input limit.