Fuzzy logic application for improving speed control and captured energy using the wind speed information for wind turbines

This paper describes a fuzzy logic application for improving the variable speed and blade pitch wind turbine performance. The simulated model is going to be implemented using a programmable logic controller as the fuzzy controller designed. The used fuzzy controller as well as improving transition between power optimization and power limitation of the wind turbine at rated wind speed, it also permits to improve the captured wind energy at high wind speed working conditions using wind speed as input controller

Comparison of dynamic response and stability of PID, PI-D, PD2DOF and PD fuzzy controllers on a mechanical system

Automation gains ground in the industrial sector day by day as a result of the new and more efficient control algorithms, in this context, the classical theory of control is a branch of knowledge established in the scientific community, but the most widely used in the industrial field, especially due to the ease of implementing a classic controller in industrial processes, even in those where the mathematical models of the systems are unknown, for example several heuristic methods for tuning PID controllers working as regulators is a widely known activity; the next step is the modern control, which is also quite developed but still has certain areas to study such as the development of optimal predictors or dealing with systems with communication delay. Finally, intelligent control is the branch of study that generates the most interest nowadays. It tries to combine artificial intelligence techniques with automatic control. One of the most popular intelligent control methods is fuzzy control or fuzzy logic control, in this work, different classical, modern and intelligent control techniques will be implemented to a line follower robot to evaluate the performance, stability and response of each one, as well as its implementation costs

Cylinder Position Servo Control Based on Fuzzy PID

The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm

A Study on the Performance Improvement of the Nonlinear Fuzzy PID Controller

PID controllers have been widely used for industrial processes but to its simplicity and effectiveness. They provide high sensitivity and stability of the overall feedback control system and reduce overshoot and steady-state error. It has been well known that PID controllers can be effectively used for 1st and 2nd-order linear systems, but they can suffer from problems on higher-order and nonlinear systems. On the other hand, fuzzy controllers in general are suitable for many nontraditionally modeled industrial processes such as linguistically controlled systems that cannot be precisely described by mathematical model formulation and have significant unmodeled effects and uncertainties. There are several types of control systems that adopt a fuzzy logic controller as an essential system component. The majority of applications during the past two decades belong to the class of fuzzy PID controllers. This thesis describes the design principle, tracking performance, and stability analysis of a nonlinear fuzzy PID controller with fixed parameters and nonlinear fuzzy PID controllers with variable parameters. At first, the fuzzy PID controller with fixed parameters is derived from the design procedure of the conventional fuzzy linguistic controller. The resulting controller is a discrete-time fuzzy version of the conventional PID controller, which has the same structure with proportional, derivative and integral parts but has nonconstant gains. However, all the gains of fuzzy PID controller are nonlinear function of the input signals at every sampling time. The resultant fuzzy PID controller has a simple structure of the conventional PID controller but posses its self-tuning control capability. In order to increase the applicability of the fuzzy PID controller using low-level microprocessors, a simplified fuzzy PID controller is introduced. At second, a fuzzy PID controller with variable parameters, named variable parameter fuzzy PID controller, is suggested to improve the shortage of the fuzzy PID controller with fixed parameters. The fuzzy PID control action cannot be operated accurately when the scaled inputs are greater than the normalization parameter of the fuzzy input sets in case of the fuzzy PID controller with fixed parameters. If design parameters are adjusted by comparing magnitude among the inputs of the fuzzy controller at every sampling time, the partitions of all the scaled fuzzy inputs converge within regions confined by the normalization parameter and the resultant fuzzy PID controller with variable parameters can always accomplish PID control action precisely regardless of the input magnitude variation. At last, several simulations for various systems including a linear time-invariant system and a nonlinear two-tank level control system are executed in order to verify that the suggested fuzzy PID controller is superior to other fuzzy PID controllers already discussed by comparing control performances among them.Abstract 제 1 장 서 론 1 1.1 연구배경 1 1.2 연구내용 3 제 2 장 고정 파라미터 퍼지 PID제어기4 2.1 기본 구조 4 2.2 퍼지화 알고리즘 7 2.3 퍼지 제어 규칙 9 2.4 비퍼지화 알고리즘 11 2.5 고정 파라미터 퍼지 PID제어기 제어칙 14 2.6 고정 파라미터 퍼지 PID제어기 시뮬레이션 16 2.7 고정 파라미터 퍼지 PID제어기의 성능분석 및 고찰 23 제 3 장 기 연구된 가변 파라미터 비선형 퍼지PID제어기 25 3.1 가변 파라미터 퍼지 PID제어기 설계 25 3.2 가변 파라미터 퍼지 PID제어기 시뮬레이션 30 3.3 논의된 가변 파라미터 퍼지 PID 제어기의 고찰 35 제 4 장 개선된 가변 파라미터 퍼지 PID제어기의 제안 36 4.1 개선된 가변 파라미터 퍼지 PID제어기의 기본 설계 36 4.2 개선된 가변 파라미터 퍼지 PID제어기 시뮬레이션 44 제 5 장 비선형 이중 수조 시스템의 제어 53 5.1 비선형 이중 수조 시스템 설계 53 5.2 퍼지 PID제어기를 이용한 비선형 이중 수조 시스템의 시스템 성능 검증과 결과 고찰 55 제 6 장 결 론 61 참 고 문

A Feasibility Study for the Automated Monitoring and Control of Mine Water Discharges

The chemical treatment of mine-influenced waters is a longstanding environmental challenge for many coal operators, particularly in Central Appalachia. Mining conditions in this region present several unique obstacles to meeting NPDES effluent limits. Outlets that discharge effluent are often located in remote areas with challenging terrain where conditions do not facilitate the implementation of large-scale commercial treatment systems. Furthermore, maintenance of these systems is often laborious, expensive, and time consuming. Many large mining complexes discharge water from numerous outlets, while using environmental technicians to assess the water quality and treatment process multiple times per day. Unfortunately, this treatment method when combined with the lower limits associated with increased regulatory scrutiny can lead to the discharge of non-compliant water off of the mine permit. As an alternative solution, this thesis describes the ongoing research and development of automated protocols for the treatment and monitoring of mine water discharges. In particular, the current work highlights machine learning algorithms as a potential solution for pH control.;In this research, a bench-scale treatment system was constructed. This system simulates a series of ponds such as those found in use by Central Appalachian coal companies to treat acid mine drainage. The bench-scale system was first characterized to determine the volumetric flow rates and resident time distributions at varying flow rates and reactor configurations. Next, data collection was conducted using the bench scale system to generate training data by introducing multilevel random perturbations to the alkaline and acidic water flow rates. A fuzzy controller was then implemented in this system to administer alkaline material with the goal of automating the chemical treatment process. Finally, the performance of machine learning algorithms in predicting future water quality was evaluated to identify the critical input variables required to build these algorithms. Results indicate the machine learning controllers are viable alternatives to the manual control used by many Appalachian coal producers

Genetic design of multivariable control systems

In the real world there are three types of multivariable control systems. The first one is when the number of inputs is equal to the number of the outputs, this type of multivariable control system is defined as a squared multivariable control system and the main type of controller designed is a decoupling controller which minimizes interactions and gives good set-point tracking. The second type of multivariable control system is where the number of inputs is greater than the number of the outputs, for this type of system the main controller designed is a fail-safe controller. This controller remains stable if a sub-set of actuator fail. The third type of multivariable control system is the number of outputs is greater than the number of inputs, for this type of system the main controller designed is an override control system. This controller only controls a sub-set of outputs based on a lowest wins control strategy. All the three types of multivariable control systems are included in this thesis. In this thesis the design of multivariable decoupling control, multivariable fail-safe control and multivariable override control as considered. The invention of evolutionary computing techniques has changed the design philosophy for control system design. Rather than using conventional techniques such as Nyquest plots or root-loci control systems can be designed using evolutionally algorithm. Such algorithms evolve solutions using cost functions and optimization. There are a variety of system performance indicators such as integral squared error operator has been used as cost functions to design controllers using such algorithms. The design of both fail-safe and override multivariable controllers is a difficult problem and there are very few analytical design methods for such controllers. Therefore, the main objective of this thesis is to use the genetic algorithms to involve both fail-safe and override controller multivariable controllers, such that they perform well in the time-domain

Élaboration d'un logiciel d'enseignement et d'application de la logique floue dans un contexte d'automate programmable

La logique floue, ou plus généralement le traitement des incertitudes, a pour objet d'étude la représentation des connaissances imprécises et le raisonnement proche du langage humain de tous les jours. La logique floue permet d'obtenir une loi de commande souvent efficace, sans devoir faire appel à des développements théoriques importants. Elle présente l'intérêt d'incorporer des connaissances linguistiques sur la manière de piloter un processus difficile en prenant compte les expériences acquises par les utilisateurs et opérateurs du processus à commander. Plutôt que d'utiliser une approche traditionnelle fondée sur les lois de commande classique, on utilise des contrôles ayant une loi de commande basée sur les notions de la logique floue. Ces contrôleurs flous ont surtout démontré des performances plus robustes, par rapport aux systèmes traditionnels, dans les situations où le modèle mathématique du procédé était mal connu ou lorsque le comportement du procédé varie ou est non linéaire. Malgré sa présence grandissante dans les applications industrielles, la logique floue est méconnue des techniciens qui oeuvrent dans le domaine de la commande industrielle. Or, il n'existe pas de logiciel pédagogique pour l'apprentissage des notions de la logique floue. Il existe, certes, des logiciels professionnels pour la mise en oeuvre des systèmes flous, par exemple Matlab®, mais rien qui ne préconise une approche pédagogique. Notre projet de recherche propose un logiciel d'enseignement et d'application de la logique floue dans un contexte d'automate programmable. Le logiciel permet l'apprentissage rapide des concepts de base de la logique floue. Il vise à montrer les techniques d'application issues de cette nouvelle technologie pour la conduite des procédés. Le logiciel permet l'interconnexion avec un automate programmable pour effectuer un contrôle en temps réel. Un contrôleur à logique floue a été élaboré à l'aide du logiciel pour contrôler un procédé simulé et réel. Les résultats de simulation et d'expérimentation présentés démontrent bien les performances du contrôleur à logique floue. Des données expérimentales vierment valider le fonctionnement du logiciel proposé