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1.
A variable structure control (VSC) method for unstable industrial processes is proposed. The proposed control method is able to provide a highly satisfactory system performance and to tackle with robustness issues of the processes in the presence of uncertainties. An ITAE-based numerical tuning algorithm for acquiring optimal control parameters, and a direct auto-tuning mechanism for the proposed controller are also provided. The performance of the proposed VSC method is illustrated on some unstable process models including a continuous stirred tank reactor (CSTR), in order to show its effectiveness, validity and feasibility.  相似文献   
2.
Genetic Algorithms (GAs) and other Evolutionary Algorithms (EAs), as powerful and broadly applicable stochastic search and optimization techniques have been successfully applied in the area of management science, operations research and industrial engineering. In the past few years, researchers gave lots of great idea for improvement of evolutionary algorithms, which include population initialization, individual selection, evolution, parameter setting, hybrid approach with conventional heuristics etc. However, though lots of different versions of evolutionary computations have been created, all of them have turned most of its attention to the development of search abilities of approaches. In this paper, for improving the search ability, we focus on how to take a balance between exploration and exploitation of the search space. It is also very difficult to solve problem, because the balance between exploration and exploitation is depending on the characteristic of different problems. The balance also should be changed dynamically depend on the status of evolution process. Purpose of this paper is the design of an effective approach which it can correspond to most optimization problems. In this paper, we propose an auto-tuning strategy by using fuzzy logic control. The main idea is adaptively regulation for taking the balance among the stochastic search and local search probabilities based on the change of the average fitness of parents and offspring which is occurred at each generation. In addition, numerical analyses of different type optimization problems show that the proposed approach has higher search capability that improve quality of solution and enhanced rate of convergence.  相似文献   
3.
结合传统PID的控制原理,介绍一种参数自调整的PID模糊控制器。开发了一套能在线调整PID参数的模糊控制方法的软件,并分别将它和传统的PID控制器作用到数字随动系统中。对二者的控制结果进行了比较。实验结果表明,参数自调整PID模糊控制器使系统稳态性能优良,并能提高控制精度。  相似文献   
4.
Mudi RK  Dey C  Lee TT 《ISA transactions》2008,47(1):45-52
Ziegler-Nichols tuned PI and PID controllers are usually found to provide poor performances for high-order and nonlinear systems. In this study, an improved auto-tuning scheme is presented for Ziegler-Nichols tuned PI controllers (ZNPICs). With a view to improving the transient response, the proportional and integral gains of the proposed controller are continuously modified based on the current process trend. The proposed controller is tested for a number of high-order linear and nonlinear dead-time processes under both set-point change and load disturbance. It exhibits significantly improved performance compared to ZNPIC, and Refined Ziegler-Nichols tuned PI controller (RZNPIC). Robustness of the proposed scheme is established by varying the controller parameters as well as the dead-time of the process under control.  相似文献   
5.
Molten Carbonate Fuel Cell (MCFC) has been emerging as a promising renewable power system. It is still challenging to operate the MCFC to meet its varying demands because of its nonlinearity and complex dynamics. This paper proposes a novel MCFC operation framework based on PID auto-tuning control. A case study is presented to illustrate the applicability of the strategy with some comments.  相似文献   
6.
本文介绍了电梯的市场动向以及安川电机公司所热衷研制的成果。为驱动装置的更换和满足无齿轮化需要而开发的驱动电梯专用变频器L1000A,既适用于感应电动机又适用永磁电动机,对其功能、性能、特点予以概括说明。本产品L1000A不仅满足全球市场的需求,而且立足于提高基本特性、乘坐电梯的舒适性、安全、环保及调整、维护简单等设计理念,实现了该变频器的产品化。  相似文献   
7.
Considerable compliance of the lengthy oil-well drill string combined with low tool inertia and stick-slip friction between the tool and the rock bed causes notable undesired torsional vibrations of the drill-string electrical drive. In order to attenuate the torsional vibrations and, thus, improve both the quality and the productivity of the drilling process, an automatically tuned active damping control strategy based on drill-string torque estimation is proposed in the paper. The core of the strategy includes a proportional-integral (PI) controller extended with estimator-based drill-string torque feedback loop. Furthermore, an appropriate algorithm that prevents drill-string back-spinning caused by the limited braking power of the power converter is presented. Finally, an auto-tuning algorithm is proposed, which is built around an adaptive Kalman filter-based estimator of drill-string drive natural frequencies. The drill-string control strategy is verified experimentally using a drill string hardware-in-the-loop setup under the laboratory conditions, as well as on an actual oil-drilling rig.  相似文献   
8.
Precise looper simulation for hot strip mills using an auto-tuning approach   总被引:2,自引:0,他引:2  
A looper is an uplifted device, which is always installed between adjacent stands in a hot strip finishing mill. A virtual looper system incorporating powerful computation capability of digital computers becomes an efficient and cost-effective tool for controller design and system analysis of this complicated and gigantic system. Accurate simulation of the looper system can not only restore the actual looper’s dynamic behavior, but can also analyze the factors that affect the looper response and provide useful information for further improvement of the control system. In this paper, a looper simulation system based on a conventional hot strip mill is established. Sensitivity analysis indicates that the reduction ratio is the most important parameter for the looper dynamics. Therefore, an auto-tuning technique for a variable reduction ratio is developed. Simulation results, compared with actual loopers behavior, demonstrate significant improvement in terms of accuracy.  相似文献   
9.
This study proposes an analytical design method of fractional order proportional integral (FOPI) controllers for first order plus time delay (FOPTD) systems. Suggested technique obtains the general computation equations of controllers for such systems. These equations are used to tune controller parameters to meet specified frequency and phase properties to satisfy the stability of whole system. It is found that the designed controllers not only make the system stable, but also have positive effect on the performance and robustness of the system. Main contribution of the paper lays on this thought. There proposed a concept, “frequency frame” which encloses the curves between phase and gain crossover frequencies in Bode plot. Robustness of the control system can be improved by expanding or constricting the edges of this frame and flattening the curves inside the frame. Thus, any case that leads the system to instability can be avoided. Analytically derived equations are tested with proper examples and the results are shown illustratively. Advantages and disadvantages of the method are comparatively given.  相似文献   
10.
This paper deals with the design of fractional order PIλDμ controllers, in which the orders of the integral and derivative parts, λ and μ, respectively, are fractional. The purpose is to take advantage of the introduction of these two parameters and fulfill additional specifications of design, ensuring a robust performance of the controlled system with respect to gain variations and noise. A method for tuning the PIλDμ controller is proposed in this paper to fulfill five different design specifications. Experimental results show that the requirements are totally met for the platform to be controlled. Besides, this paper proposes an auto-tuning method for this kind of controller. Specifications of gain crossover frequency and phase margin are fulfilled, together with the iso-damping property of the time response of the system. Experimental results are given to illustrate the effectiveness of this method.  相似文献   
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