• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.3
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• pp.188-195
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• 2004

This paper presents neural load torque observer that is used to deadbeat load torque observer and gain compensation by parameter estimator As a result, the response of the PMSM(permanent magnet synchronous motor) follows that nominal plant. The load torque compensation method is composed of a neural deadbeat observer To reduce the noise effect, the post-filter implemented by MA(moving average) process, is adopted. The parameter compensator with RLSM (recursive least square method) parameter estimator is adopted to increase the performance of the load torque observer and main controller The parameter estimator is combined with a high performance neural load torque observer to resolve the problems. The neural network is trained in on-line phases and it is composed by a feed forward recall and error back-propagation training. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. As a result, the proposed control system has a robust and precise system against the load torque and the Parameter variation. A stability and usefulness are verified by computer simulation and experiment.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.52-59
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• 2013

Recently, the importance of the efficient production pipeline design has been increased for 3D animation, which becomes more delicate. In this paper, we propose 3D animation character development pipeline using 3D printing technology. We introduce 3D printing procedure into each step of the classical 3D animation and character development pipeline to incorporate the feed-back from the designer immediately. Specially, during the production step, we can find the design errors and minimize the period of production by using 3D printing of approximate shape of designed character. Using proposed method, eight DreaMegg characters were developed and their quality was very high with respect to 3D virtual graphics and real product. Using our method, high-quality 3D animation character can be developed with the minimized time and cost for development by reflecting the feed-back into production line from designers and researchers immediately.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.957-960
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• 2008

The purpose of this study is to explore a safe, advanced, and environment-friendly demolition equipments and their operation methods. As an initial achievement, the capacity of the existing equipments have been evaluated through technical discussions and demonstrations with some experts in the related industry. From these evaluations, it was concluded that a haptic based remote control with force feed-back mechanism and sensor fusion functions would be the most appropriate to the demolition equipments. Therefore, a novel haptic device that is adequately designed for the demolition equipments is proposed in this paper. Top-down demolition method is also proposed, which is very effective in the demolition of high-rise buildings.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.117-126
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• 1994

This paper describes an application step of a $R^{-{\theta}}$ method which measures circular movements in machining centers. The detection of composite errors of circular movements and a high precision cutting method in machining centers were investigated by the analysis of data measured by $R^{\theta }$method which can detect the rotating angle and is applicable to variable measuring radius. When the error by squareness error and unbalance of position-loop-gain were mixed, the detection method of each error was proposed. Although the errors by squarenss error and backlash compensation were mixed, the errors by squareness error be detected. If the errors by unbalance of position-loop-gain and backlash compensation were mixed, the errors by unbalance of position-loop-gain could not detected. A high precision cutting mehod, which uses the NC program compensated by using feed-back data from error measured by the $R^{\theta }$method, was proposed.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.2
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• pp.244-250
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• 2003

In this paper, the relationship between a slave robot and the uncertain remote environment is modeled as the impedance to generate the virtual force to feed back to the operator. For the control of a tele-operated mobile robot equipped with camera, the tele-operated mobile robot take pictures of remote environment and sends the visual information back to the operator over the Internet. Because of the limitation of communication bandwidth and narrow view-angles of camera, it is not possible to watch the environment clearly, especially shadow and curved areas. To overcome this problem, the virtual force is generated according to both the distance between the obstacle and robot and the approaching velocity of the obstacle. This virtual force is transferred back to the master over the Internet and the master(two degrees of freedom joystick), which can generate force, enables a human operator to estimate the position of obstacle in the remote environment. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. This force reflection improves the performance of a tele-operated mobile robot significantly.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1700-1707
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• 2011

Interior permanent magnet synchronous motor(IPMSM) adjustable speed drives offer significant advantages over induction motor drives in a wide variety of industrial applications such as high power density, high efficiency, improved dynamic performance and reliability. Since the fuzzy neural network(FNN) is recognized general approximate method to control non-linearities and uncertainties, the development of FNN control systems have also grown rapidly. The FNN controller is compounded of fuzzy and neural network. It has an advantage that is the robustness of fuzzy control and the ability to adapt of neural network. However, the FNN has static problem due to their feed-forward network structure. This paper proposes high performance speed control of IPMSM drive using the recurrent FNN(RFNN) which improved conventional FNN controller. The RFNN has excellent dynamic response characteristics because of it has internally feed-back structure. Also, this paper proposes speed estimation of IPMSM drive using ANN. The proposed method is analyzed and compared to conventional FNN controller in various operating condition such as parameter variation, steady and transient states etc.

• Korean Journal of Community Nutrition
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• v.1 no.3
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• pp.433-440
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• 1996

This study was carried out using a questionnaire in order to investigate factors affecting the status and the method of infant feeding in Incheon area. The subjects were 126 monthers of infants ranging from 3 months to 18 months. The results are : the percentages of those feeding colostrum and breast milk has decreased in comparison with the previous results. But the percentage of breast-feeding gets higher in a case where colostrum or breast milk is first fed after delivery. Also frequency and birth order of child plays a part : the more frequently monthers try to feed breast milk in the earliest period of feeding, the more they keep breast-feeding, and the latter-born(the second-born or the third born) children get more chances to be breast-fed than the first-born. Another noticeable factor is what babies feed on during hospitalization. if they get fed more breast milk than infant formula while they are in hospital, they tend to keep feeding on breast milk after they come back home. Breast-feeding group have good knowledge and information abut the importance of breast-feeding. The data shows that they believe the superiority of breast milk.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.726-733
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• 2005

A spherical surface referenced Shack-Hartmann method is studied for inspecting machining accuracy of large concave mirror This method is so strong to the vibration environment for using as an on-machine inspection system during polishing process of large optics comparing with the interferometry. The measuring uncertainty of the system is shown as less than p-v 150 m. On-machine measured surface profile data with this method is used for feed back control of the polishing time or depth to improve the surface profile accuracy of large concave mirror. Also, the spherical surface referenced Shack-Hartmann method is useful for measuring aspheric such as parabolic or hyperbolic surface profile, comparing that the interferomehy needs a special null lens, which is to be a reference and difficult to fabricate.

• Journal of Advanced Marine Engineering and Technology
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• v.6 no.2
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• pp.42-50
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• 1982

The controller, generally, is to be designed to optimize the system in somesence subject to some constraints. In this paper the method to determine the optimal parameters of the PI controller in the unity feed back control system is proposed. Here the sence of the optimal is to minimize the integral of the squared error under the constraints that the maximum absolute value of control input, maximum overshoot, rise time, etc., should be smaller than the pre-given values. In the analysis the traditional method and the state variable method are combined in order to reduce the computational procedures required in the design of PI controller. Therefore, the procedure proposed in the paper is usefully applicable to the controller system with a general second-order plant. Finally, the indicial response curves generated at the optimal state are compared with those of non-optimal state and the effectiveness of this method is assertained.

• Transactions of Materials Processing
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• v.30 no.3
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• pp.125-133
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• 2021

In this study, response surface method (RSM), back propagation neural network (BPNN), and genetic algorithm (GA) were used for modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goal of optimization is to determine the maximum forming angle and minimum surface roughness, while varying the production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model and BPNN model to model the variations in the forming angle and surface roughness based on variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process the GA. The results showed that RSM and BPNN can be effectively used to control the forming angle and surface roughness. The optimized Pareto front produced by the GA can be utilized as a rational design guide for practical applications of AA5052 in the ISF process