• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.416-419
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• 2001

In this paper a new approach to estimate scaling factors of fuzzy controllers such as the fuzzy PID controller and the fuzzy PD controller is presented. The performance of the fuzzy controller is sensitive to the variety of scaling factors[1]. The desist procedure dwells on the use of evolutionary computing(a genetic algorithm) and estimation algorithm for dynamic systems (the inverted pendulum). The tuning of the scaling factors of the fuzzy controller is essential to the entire optimization process. And then we estimate scaling factors of the fuzzy controller by means of two types of estimation algorithms such as Neuro-Fuzzy model, and regression polynomial [7]. This method can be applied to the nonlinear system as the inverted pendulum. Numerical studies are presented and a detailed comparative analysis is also included.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.220-227
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• 1999

The position control accuracy of a robot arm is significantly deteriorated when a long slender arm robot is operated at a high speed. In this case, the robot arm needs to be modeled as a flexible structure, not a rigid one, and its control system needs to be designed with its elastic modes taken into account. In this paper, the vibration control scheme of a one-link flexible manipulator using adaptive input shaper in conjunction with PID controller is presented. The robot consists of a flexible arm manufactured with a thin aluminium plate, an AC servo motor with a harmonic drive for speed reduction, an optical encoder and an accelerometer. On-line identification of the vibration mode is done using the pruned decimation-in-time FFT algorithm to estimate the parameter of the input shaper. Experimental results of the flexible manipulator with a PID controller and input shaper are provided to show the effectiveness of the advocated controllers.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.309-312
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• 1999

This paper proposed a novel method for pseudo-on-line scheme using look-up table based on the genetic algorithm The technique is an pseudo-on-line method that optimally estimate the parameters of FPID controller for systems with non-linearity using the genetic algorithm which does not use the gradient and finds the global optimum of an unconstraint optimization problem. The proposed controller is applied to speed control of 3-phase induction motor and its computer simulation is carried out. Simulation results show that the proposed method is more excellent then conventional FPID and PID controllers.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.658-662
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• 1986

In the microcomputer-based velocity control for an electro-hydraulic servo system, the effects of control methods and control hardware on the performance of the system were investigated. Experiments were carried out with PID and deadbeat controllers using 8 or 16 bit microprocessor and 8 or 12 bit A/D and D/A converters. It is found that the transient response of the system is better with PID controller than with deadbeat controller. When the number of bits of the microprocessor and converters are small, it is also found that amplitude quantization due to limited wordlength gives significant effects on transient responses of the system. Analytically predicted step-responses are in good agreement with experimental ones.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1025-1030
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• 2009

It is known that the classical tuning formula for typical PID controllers in general provides unsatisfactory results for industrial plants where the time delay exceeds the dominant lag time. For this reason, alternative strategies have been studied in order to cope with this problem and the most popular scheme is the Smith Predictor(SP). In this paper, the dynamic model of a unit apartment in the district heating system, which is the control process effected by the dead-time, is developed, and the on/off room temperature control method with the SP simulate using Matlab-Simulink. The simulation results show that the SP works effectively in outdoor temperature variation.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.80-88
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• 2002

As many sensors and actuators are used in automated systems, various industrial networks are adopted for digital control system. In order to take advantages of the networking, however, the network implementation should be carefully designed to satisfy real-time requirements considering network delays. This paper presents the implementation scheme of a networked control system via Profibus-DP network. More specifically, the effect of the network delay on the control performance was evaluated on a Profibus-DP testbed, and a GA-based PID tuning algorithm is proposed to design controllers suitable for networked control systems.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.4
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• pp.441-447
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• 1998

Motivated by a recent work, a fuzzy-power-controller(FPC) is designed for the relieving-horsepower control of output variable pump with electrical proportional valve and actually implemented on the industrial excavator. In order to calculate the output power of pump with input of FPC, a linear discrete time model of load system to pump is obtained and the result is applied to control the engine-pump coupled system by software without pressure and flow sensor. The FPC controls the engine and pump coupled system by relieving horsepower control according to the change of load and the running conditions in relieving horsepower control are selected by fuzzy inference engine. A case study is peformed through the construction of the control device and installation on the excavator. It shows that the relieving-horsepower control system with the FPC, as suggested in this paper, is superior to the conventional PID controllers. And also, the excavator, with the FPC, shows that the power-loss of the coupled system is reduced and the running speed of the hydraulic actuator is enhanced.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.775-777
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• 1998

The Ziegler-Nichols parameter tuning has been widely known as a fairly heuristic method to good determine setting of PID controllers, for a wide range of common industrial processes. We extract process knowledge required for rule base controller through tuning experiment and simulation study, such as set point weighting and normalised gain and dead time of process. In this paper, we presents a rule base PID controller by extracted process knowledge and the modified Ziegler-Nichols tuning. Computer simulation are provided demonstrate the feasibility of this approach.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.538-545
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• 1995

The heat transfer model of ondol heating system is derived in the linear form. The step responses of On-Off controller, PID controller and Position type fuzzy controllers are compared in the sense of several aspects : variation of temperature feedback variable, variation of supplied heat quantity by the boiler, variation of flow rate, variation of thickness of the base, variation of the outdoor temperature.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.78-86
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• 2003

Multivariable control system exist widely in many types of systems such as chemical processes, biomedical processes, and the main steam temperature control system of the thermal power plant. Up to the present time, Pill Controllers have been used to operate these systems. However, it is very difficult to achieve an optimal PID gain with no experience, because of the interaction between loops and gain of the Pill controller has to be manually tuned by trial and error. This paper suggests a tuning method of the Pill Controller for the multivariable power plant using an immune algorithm, through computer simulation. Tuning results by immune algorithms based neural network are compared with the results of genetic algorithm.