1,720,975 research outputs found
Multi-Agent Fuzzy Logic Controller applied to One Lever Variable Pitch Turboprop Aircraft
Full text linkModern aircraft turboprop engines are generally managed by pilots by using the well-established two-levers approach which allows the pilot to control independently the engine thrust (power lever) and the propeller rotational speed (condition lever). On the other hand, the twolevers governing system presents several disadvantages in terms of pilot training, fuel consumption and aircraft maintenance. The one-lever approach tries to solve such drawbacks regulating at the same time the engine power and the propeller pitch. In the present work a Multi-Agent Fuzzy Logic control algorithm has been proposed to implement the one-lever approach for the control of the variable pitch turboprop aircraft propulsion system. The whole aircraft ecosystem has been developed in Simulink® framework to verify the feasibility and performance of the proposed one-lever approach
Estimator based adaptive fuzzy logic control technique for a wind turbine–generator system
No full textThe control of a wind power plant, operating as an isolated power source, is analyzed. The plant consists of a wind turbine and a three phase synchronous electric generator, connected by means of a gear box. The mathematical models of the wind turbine and of the electrical generator are indicated. The use of an estimator based adaptive fuzzy logic control technique to govern the system is proposed. The results of a control test case are shown in order to demonstrate the reliability of the proposed control techniqu
Multi-objective sensitivity analysis of shell-and-tube LHTES performance
Full text linkIn the present paper a sensitivity analysis has been carried out concerning the charging/discharging time and the stored energy performances of a shell-and-tube LHTES with respect to the number of tubes and the tube internal radius. The aim of this analysis is to investigate how the design variables affect the LHTES performance. this could lead to determine the thermal storage optimal design. Thus, the sensitivity analysis has a key role in the selection of several acceptable solutions. The considered LHTES exhibits a cylindrical shell geometry characterized by constant height and diameter. This aspect has allowed to employ simplified theoretical models able to predict the charging/discharging time and the stored energy performance. These models consider a constant heat exchange wall temperature whereas the heat exchange area and the whole PCM volume vary according to the design variables. This analysis represents the first step to solve the multi-objective optimization of the thermal storage design problem and then to determine the best solutions in both design variables and thermal storage performance domains
Control of Gas turbine power plants by means of the weighted one-step-ahead adaptive technique
No full textThe one-step-ahead controllers represent a branch of minimum prediction error adaptive controllers. They combine the parameter estimation of the controlled system model with the control scheme; therefore, they are especially suitable for non-linear and time-varying systems. Since the estimated parameters are updated at each time step (by using the sampled data), these methods can be adopted for non-linear applications. Consequently, the one-step-ahead controllers do not require knowledge of the dynamic characteristics of the controlled system (e.g. state-space systems or transfer functions). Sometimes, in the gas turbine field, the control system could produce an excessive control effort, due to sudden variations of the electric load. In order to reduce this control action, the weighted one-step-ahead adaptive (WOSAA) control algorithm considers a penalty associated with the control effort using an appropriate cost function. In this way, the control variable does not assume values that are too large, even when the gas turbine undergoes sudden changes in the external load. As a consequence, the robustness and stability features of the WOSAA control system are increased. The results show that the WOSAA control technique, applied to both the double-shaft aero-derivative gas turbine and the single-shaft heavy-duty gas turbine, effectively counteracts the load reduction with limited overshoot in the controlled variables with reduced control effort
Performance of gas turbine power plants controlled by the multiagent scheme
No full textIn recent years the idea of artificial intelligence has been focused around the concept of rational
agent. An agent is a (software or hardware) entity that can receive signals from the environment and act
upon that environment through output signals, trying to carry out an appropriate task. Seldom agents are
considered as stand-alone systems; on the contrary, their main strength can be found in the interaction
with other agents, constituting the so called multiagent system.
In the present work, a multiagent system was chosen as control system of a single-shaft heavy-duty
gas turbine in Multi Input Multi Output mode. The shaft rotational speed (power frequency) and stack
temperature (related to the overall gas turbine efficiency) represent the controlled variables; on the other
hand, the fuel mass flow (VCE) and the Variable Inlet Guide Vanes (VIGV) have be chosen as manipulating
variables.
The results will show that the multiagent approach to the control problem effectively counteracts the
load reduction (including the load rejection condition) with limited overshoot in the controlled variables
(as other control algorithms do) while showing good level adaptivity readiness, precision, robustness and
stability
VGT Turbocharger Controlled by an Adaptive Technique
No full textThis paper provides an adaptive technique for the control of the variable geometry turbine in a turbocharged compression ignition engine. The adaptive control is based on a one-step-ahead (OSA) technique and a least-square parameter estimator algorithm. In order to test the performance of the proposed control technique, a numerical model of the engine has been developed, which employs a thermodynamic (zero-dimensional) approach. The paper will show that the OSA technique is able to improve dramatically the control performance with respect to that provided by a commonly applied proportional integral derivative control technique
Fuzzy logic controller applied to a variable geometry turbine turbocharger
No full textThis paper provides an adaptive technique for the control of a variable geometry turbine (VGT) in a turbocharged compression ignition engine. The adaptive control is based on a fuzzy logic control scheme and a least-squares parameter estimator algorithm. In order to test the performance of the proposed control technique, a numerical model of the engine has been used, which employs a thermodynamic (zero-dimensional) approach. The paper will show that the fuzzy logic control technique is able to take into account the non-linearity of the controlled system and to reject white noise affecting the measurement chain
One-step-ahead adaptive control of a wind-driven, synchronous generator system
No full textControl of a wind power plant as an isolated power source is analyzed. The plant consists of a wind turbine (connected by means of a gear box to a three-phase synchronous electric generator) and a control system. Mathematical models of the wind turbine and electrical generator have been proposed. The one-step-ahead adaptive control technique has been adopted to govern the system. Results of a control test case are shown in order to demonstrate the reliability of the proposed control technique
Multiple-attribute decision support systems based on fuzzy logic for performance assessment
No full textThis paper deals with the problem of assessing the performance of a set of production units, simultaneously considering different kinds of information, yielded by a Data Envelopment Analysis, a qualitative data analysis and an expert assessment. The tool for integrating heterogeneous data is a model that applies fuzzy logic to decision support systems. The results obtained are a holistic performance assessment of each unit of the set and a ranking order of the units
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