• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.358-363
• /
• 2003

Optimal tuning plays an important role in operations or tuning of the complex process such as the main steam temperature of the thermal power plant. However, it is very difficult to maintain the steam temperature of power plant using conventional optimization methods, since these processes have the time delay and the change of the dynamic characteristics in the reheater. Up to the present time, the Pm controller has been used. However, it is not easy to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper suggests immune algorithm based tuning technique for PID Controller on steam temperature process with long dead time and its results are compared with genetic algorithm based tuning technique.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1228-1229
• /
• 2011

A novel approach has been promoted for FNN ship controllers. An Electro-hydraulic governor has been widely adopted to the ship speed control of propulsion marine diesel engines for a long time, it was very difficult for Electro-hydraulic governor to regulate the speed of high power engine with long stroke at low speed and low load, because of the jiggling phenomena by rough fluctuation of rotating torque and the hunting phenomena by long dead time occurred in fuel combustion process in the engine cylinder. This paper provides an efficient way for improving control performance by FNN controller. An RBF neural network and GA optimization are employed in a fuzzy neural controller to deal with the nonlinearity, time varying and uncertain factors, the rule base and membership functions can be auto-adjusted by GA optimization. The parameters of neural network can be decreased by using union-rule configuration in the hidden layer of the network. The performance of controller is evaluated by the system simulation using simulink tools.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.4
• /
• pp.1537-1547
• /
• 2017

In this paper, a discrete-time robust current controller is proposed for PMSM drives. The structure of the proposed controller is quite simple and does not require high computational resource. The only difference of the proposed controller from the classical dead-beat controller is the integral term which can easily be implemented in a PMSM drive. The stability analysis of the proposed controller is performed accounting in parametric uncertainties, unmodelled dynamics and disturbances in the mathematical model. The boundedness of the dynamical system and asymptotic convergence of dq-axes currents to their reference values are provided under certain conditions. Various simulation and experimental studies are performed and the results taken at different operation conditions show the validity of the proposed controller.

• Proceedings of the KIEE Conference
• /
• 1991.07a
• /
• pp.717-719
• /
• 1991

In this paper, the basic principle and theory of fuzzy control was discribed, and the control plant was estabilished to construct system. Computer software for fuzzy control was developed, and evaluation of the properties was performed by simulation. In this result, the speed of response(time constant + dead time) was investigated, and when the control plant has astable elements, the stabilization was discribed.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.2
• /
• pp.199-208
• /
• 1992

MIESF(Modified Integral Error and State Feedback) controller suggested in order to control the processes with time delay is the control scheme that combines Smith predictor and IESF(Integral Error and State Feedback). This control scheme has better performance than the conventional PID controller incorporating Smith predictor with respect to the robustness and control performance for the modelling error. MIESF controller can be simply designed by pole assignment algorithm. BUT in such a case, it is difficult to find proper poles which gurantee robustness with respect to process parameter uncertainties. In order to solve the aforementioned difficulties, we suggest a new design method for MIESF controller and show the validity of the proposed design method.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.8
• /
• pp.2449-2457
• /
• 1996

This paper presents a design method for autopilot control system in course change to the specified direction based on a robust digital servo controlmelthod incorporating the concept of the annihilator polynormial. The mathematicalmodel of ship turning motion is very complex in the view of practical control because it has time varying parameters, nonlinear and dead time terms. To apply the digital servo control method based on computer control, the model is linearized at an equilibrium point and discretized with appropriate sampling time. The control algorithm was evaluated on the basis of computer simulation for a model ship and the practical experiment was carried out with an image processing method for measurement of ship position in a water tank. The results of overall experiments show that the proposed control method will be one of good way to keep a track plotted in the map.

• Food Science of Animal Resources
• /
• v.24 no.4
• /
• pp.424-432
• /
• 2004

The handling and transport of broiler birds from farm to the processing factory is known to cause injury and dead. The preslaughter period can be compromised through thermal stress, emotional stress, starvation, dehydration, metabolic exhaustion, trauma to the skin and bone fraction resulting in bruising and dead. This paper focuses on the control points of individual post Harvest stages by reference to recent literature. In catching, the injuries and deads are caused from fracture of bone, skin damage and hipbone dislocation. It can be improved by training the catchers. The primary factor of dead during transportation is from thermal stress. It is related to stocking density, type of crate and vehicle, ventilation and transportation time. Of the factors, the ventilation is very important. The holding place should be built with consideration of protection from the hostile external environment. There were not much progresses in this area, however, many researches are conducting to focus on animal welfare in European Union. Recently, it is rapidly changed in marketing custom from whole carcass to portion cut in Korea. This means the increase of economic loss due to the mishandling at post harvest. The systematic approach is demanded for this area.

• Proceedings of the IEEK Conference
• /
• 2003.07c
• /
• pp.2593-2596
• /
• 2003

The deadbeat properties have been well known in designing digital control systems. But recently several researchers proposed a CDBC(Continuout-time DeadBeat Controller) in continuous time. They used delay or smoothing elements from the finite Laplace Transform. A delay element is made by the exponential terms. A smoothing element is used to smooth the digital control input. And eventually the process is argumentd with smoothing elements and then well-known digital deadbeat controller is designed Sometimes samplings are done in continuous time systems and some hold devices are used to relate to digital systems. So multirate sampling may enhance the efficiency of the CDBC. A DC servo motor is chosen for implementing CDBC algorithm. Especially Outputs according to the variable input and disturbance are simulated. by use of Matlab Simulink.

• The Korean Journal of Physiology
• /
• v.9 no.1
• /
• pp.57-61
• /
• 1975

A study was designed to clarify the influence of the hippocampus upon tolerance by electric shock. Forty-eight male rats were used, of which 14 rats had their hippocampal tissue on both sides removed through an opening in the parieto-occipital cortex (hippocampal group), 17 rats received damage to the parieto-occipital cortex only (cortical control group), and 17 rats served as normal control animals. After 24 hours' fasting with water ad libitum, each animal was restrained on a plate with added electric shock (4 mA A.C., 1.5 sec in a duration, and once per minute in average) to the tail for the last 24 hours without food and water. The mortality in each animal group and the mean survival time of the dead animal during the repitition of electric shock were calculated. Results obtained were as follows: 1. The mortality was lower significantly in the hippocampal group than in the two control groups. 2. The mean survival time of the dead animal was longer insignificantly in the hippocampal group than in the two control groups. The inference from the above results is that the hippocampus exerts a inhibitory influence upon tolerance by electric shock.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.1 no.1
• /
• pp.7-11
• /
• 1996

From the cost-effective point of view, it is very important to design a current with the highest utilization factor of current capacity of power devices. This can be accomplished by a current controller without overshoot irrespective of the varying bounds of control voltage in PWM converters and the dead time due to the time delay. This paper suggests a novel decoupled controller with Smith-Predictor which has the fast control response without overshoot and steady stats error and also deal with the design method of the controller for PWM converters. The extensive digital simulations done by SIMULINK/MATLAB show that the suggested controller guarantees the full utilization of current capacity of power devices and the decoupled current control behavior.