scholarly journals An Unmanned Aircraft Model for Control System Reconfiguration Analysis and Synthesis

2017 ◽  
Vol 2017 (2) ◽  
pp. 97-116
Author(s):  
Marcin Żugaj ◽  
Przemysław Bibik ◽  
Marcin Figat
Keyword(s):  
Control System ◽  
Linear Model ◽  
Dynamic Properties ◽  
Unmanned Aircraft ◽  
Control Surface ◽  
Aircraft Model ◽  
Non Linear ◽  
Analysis And Synthesis ◽  
The Impact ◽  
Control Surfaces

Abstract Reliability of unmanned aircraft is a decisive factor for conducting air tasks in a controlled airspace. One of the means of improving unmanned aircraft reliability is reconfiguration of the control system, which will allow to maintain control over the aircraft despite an occurring failure. The control system is reconfigured by using still operational control surfaces to compensate for failure consequences and to control the damaged aircraft. Development of effective reconfiguration algorithms involves utilization of a non-linear model of unmanned aircraft dynamics, in which each control surface deflection can be controlled independently. The paper describes a non-linear model of a small unmanned aircraft with decoupled control surfaces. The paper discusses aircraft flight dynamics equations and estimated equations for controllability derivatives for each control surface, the results of comparison tests of the model and actual aircraft as well as the structure of the simulation model. The developed unmanned aircraft model may be used in development and in optimization of control algorithms for aircraft with damaged control systems as well as to test the impact of failures on dynamic properties of the aircraft.

scholarly journals Reconfiguration of Unmanned Aircraft Control System

2017 ◽  
Vol 2017 (2) ◽  
pp. 80-96
Author(s):  
Marcin Żugaj
Keyword(s):  
Control System ◽  
Unmanned Aircraft ◽  
Control Surface ◽  
Control Input ◽  
Aircraft Control ◽  
System Failures ◽  
System Reconfiguration ◽  
And Control ◽  
Control Surfaces ◽  
Aircraft Control System

Abstract Reliability of unmanned aircraft is a decisive factor for conducting air tasks in controlled airspace. One of the means used to improve unmanned aircraft reliability is reconfiguration of the control system, which will allow to maintain control over the aircraft despite occurring failures. The control system is reconfigured by using operational control surfaces, to compensate for failure consequences and to control the damaged aircraft. Development of effective reconfiguration algorithms involves utilization of a non-linear model of unmanned aircraft dynamics, in which deflection of each control surface can be controlled independently. The paper presents a method for an unmanned aircraft control system reconfiguration utilizing a linear and nonlinear model of aerodynamic loads due to control. It presents reconfiguration algorithms, which differ with used models and with optimization criteria for deflections of failure-free control surfaces. Additionally it presents results of a benchmark of the developed algorithms, for various types of control system failures and control input.

Selection of models to describe the temperature-dependent development of Neoleucinodes elegantalis (Lepidoptera: Crambidae) and its application to predict the species voltinism under future climate conditions

2021 ◽  
pp. 1-9
Author(s):  
Hevellyn Talissa dos Santos ◽  
Cesar Augusto Marchioro
Keyword(s):  
Climate Change ◽  
Linear Model ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Temperature Dependent ◽  
Dependent Development ◽  
Degree Day ◽  
Non Linear ◽  
The Impact

Abstract The small tomato borer, Neoleucinodes elegantalis (Guenée, 1854) is a multivoltine pest of tomato and other cultivated solanaceous plants. The knowledge on how N. elegantalis respond to temperature may help in the development of pest management strategies, and in the understanding of the effects of climate change on its voltinism. In this context, this study aimed to select models to describe the temperature-dependent development rate of N. elegantalis and apply the best models to evaluate the impacts of climate change on pest voltinism. Voltinism was estimated with the best fit non-linear model and the degree-day approach using future climate change scenarios representing intermediary and high greenhouse gas emission rates. Two out of the six models assessed showed a good fit to the observed data and accurately estimated the thermal thresholds of N. elegantalis. The degree-day and the non-linear model estimated more generations in the warmer regions and fewer generations in the colder areas, but differences of up to 41% between models were recorded mainly in the warmer regions. In general, both models predicted an increase in the voltinism of N. elegantalis in most of the study area, and this increase was more pronounced in the scenarios with high emission of greenhouse gases. The mathematical model (74.8%) and the location (9.8%) were the factors that mostly contributed to the observed variation in pest voltinism. Our findings highlight the impact of climate change on the voltinism of N. elegantalis and indicate that an increase in its population growth is expected in most regions of the study area.

Heat and Cold-related Hospitalization Risk in North-East of Iran: A Time-stratified Case Crossover Design

2021 ◽  
Author(s):  
Omid Aboubakri ◽  
Hamid Reza Shoraka ◽  
Joan Ballester ◽  
Rahim Sharafkhani
Keyword(s):  
Linear Model ◽  
Hospital Admissions ◽  
Extreme Values ◽  
Crossover Design ◽  
Preventive Program ◽  
North East ◽  
Distributed Lag ◽  
Case Crossover ◽  
Non Linear ◽  
The Impact

Abstract Background: This study aimed to estimate hospitalization risk/number attributed to air extreme temperatures using time-stratified case crossover study and distributed lag non-linear model in a region of Iran during 2015-2019.Methods: A time-stratified case crossover design based on aggregated exposure data was used in this study. In order to have no overlap bias in the estimations, a fixed and disjointed window by using one-month strata was used in the design. A conditional Poisson regression model allowing for over dispersion (Quasi-Poisson) was applied into Distributed Lag Non-linear Model (DLNM). Different approaches were applied to estimate Optimum Temperature (OT). In the model, the interaction effect between temperature and humidity was assessed to see if the impact of heat or cold on Hospital Admissions (HAs) are different between different levels of humidity.Results: The cumulative effect of heat during 21 days was not significant and it was the cold that had significant cumulative adverse effect on all groups. While the number of HAs attributed to any ranges of heat, including medium, high, extreme and even all values were negligible, but a large number was attributable to cold values; about 10000 HAs were attributable to all values of cold temperature, of which about 9000 were attributed to medium range and about 1000 and less than 500 were attributed to high and extreme values of cold, respectively.Conclusion: This study highlights the need for interventions in cold seasons by policymakers. The results inform researchers as well as policy makers to address both men and women and elderly when any plan or preventive program is developed in the area under study.

scholarly journals Linear and Non-Linear Models for Remotely-Sensed Hyperspectral Image Visualization

2020 ◽  
Vol 12 (15) ◽  
pp. 2479
Author(s):  
Radu-Mihai Coliban ◽  
Maria Marincaş ◽  
Cosmin Hatfaludi ◽  
Mihai Ivanovici
Keyword(s):  
Linear Model ◽  
Linear Models ◽  
Hyperspectral Image ◽  
Point Of View ◽  
Hyperspectral Images ◽  
Image Visualization ◽  
Color Formation ◽  
Amount Of Information ◽  
Non Linear ◽  
The Impact

The visualization of hyperspectral images still constitutes an open question and may have an important impact on the consequent analysis tasks. The existing techniques fall mainly in the following categories: band selection, PCA-based approaches, linear approaches, approaches based on digital image processing techniques and machine/deep learning methods. In this article, we propose the usage of a linear model for color formation, to emulate the image acquisition process by a digital color camera. We show how the choice of spectral sensitivity curves has an impact on the visualization of hyperspectral images as RGB color images. In addition, we propose a non-linear model based on an artificial neural network. We objectively assess the impact and the intrinsic quality of the hyperspectral image visualization from the point of view of the amount of information and complexity: (i) in order to objectively quantify the amount of information present in the image, we use the color entropy as a metric; (ii) for the evaluation of the complexity of the scene we employ the color fractal dimension, as an indication of detail and texture characteristics of the image. For comparison, we use several state-of-the-art visualization techniques. We present experimental results on visualization using both the linear and non-linear color formation models, in comparison with four other methods and report on the superiority of the proposed non-linear model.

Artificial neural network based robust speed control of permanent magnet synchronous motors

2006 ◽  
Vol 25 (1) ◽  
pp. 220-234 ◽  
Author(s):  
Tomasz Pajchrowski ◽  
Konrad Urbański ◽  
Krzysztof Zawirski
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Control System ◽  
Speed Control ◽  
Controller Synthesis ◽  
Control Surface ◽  
Content Type ◽  
Linear Characteristic ◽  
Non Linear ◽  
Artificial Neural

PurposeThe aim of the paper is to find a simple structure of speed controller robust against drive parameters variations. Application of artificial neural network (ANN) in the controller of PI type creates proper non‐linear characteristics, which ensures controller robustness.Design/methodology/approachThe robustness of the controller is based on its non‐linear characteristic introduced by ANN. The paper proposes a novel approach to neural controller synthesis to be performed in two stages. The first stage consists in training the ANN to form the proper shape of the control surface, which represents the non‐linear characteristic of the controller. At the second stage, the PI controller settings are adjusted by means of the random weight change (RWC) procedure, which optimises the control quality index formulated in the paper. The synthesis is performed using simulation techniques and subsequently the behaviour of a laboratory speed control system is validated in the experimental set‐up. The control algorithms of the system are performed by a microprocessor floating point DSP control system.FindingsThe proposed controller structure with proper control surface created by ANN guarantees expected robustness.Originality/valueThe original method of robust controller synthesis was proposed and validated by simulation and experimental investigations.

scholarly journals Wind Tunnel Tests of the Tu-154M Aircraft Aerodynamic Characteristics

2019 ◽  
Vol 26 (3) ◽  
pp. 113-120
Author(s):  
Andrzej Krzysiak
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Control Surface ◽  
Rolling Moment ◽  
Wind Tunnel Tests ◽  
Aircraft Model ◽  
University Of Technology ◽  
The Military ◽  
Control Surfaces

Abstract Determination of possible manoeuvres to be performed by the aircraft requires knowledge of its aerodynamic characteristics including, in particular, characteristics of the aircraft at configuration with deflected control surfaces. In this article, the wind tunnel tests results of the model of passenger Tu-154M aircraft manufactured at the scale 1:40 are presented. The model was designed and manufactured by the Military University of Technology based on the Tu-154M aircraft geometry obtained by full-scale object scanning. The model mapped all aircraft control surfaces, along with the gaps between these surfaces and the main wing part. During the tests all the model’s control surface like, flaps, ailerons, spoilers, slots, rudder, elevator and tail plane were deflected at the same deflection angles range as they are used in the full scale aircraft. The aerodynamic characteristics of the tested Tu-154M aircraft model were measured by the 6-component internal balance. Based on the obtained measurements the aircraft model aerodynamic coefficients were calculated. In the article the basic aerodynamic characteristics of the tested Tu-154M aircraft model i.e. lift, drag coefficients as well as pitching, yawing and rolling moment coefficients versus model angles of attack and sideslip angles were presented. The tests were performed in the Institute of Aviation low speed wind tunnels T-1 of the 1.5 m diameter test section at the undisturbed velocity, V∞ = 40 m/s.

Experimental Studies of the Rotational Speed Automatic Control System for Locomotive Engine Shafts

2020 ◽  
pp. 35-50 ◽  
Author(s):  
V.A. Markov ◽  
V.V. Furman ◽  
S.V. Plakhov ◽  
Bowen Sa
Keyword(s):  
Control System ◽  
Diesel Engine ◽  
Transient Process ◽  
Rotational Speed ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Operational Mode ◽  
Diesel Generator ◽  
Locomotive Engine ◽  
The Impact

This study addresses the problem of selecting the optimal structure and parameters of an electronic rotational speed controller for the crankshaft of a locomotive engine. An electronic control system of fuel supply ESUVT.01 developed by OOO PPP Dizelavtomatika (Saratov) for the locomotive diesel engine D50 manufactured by OAO Penzadizelmash is presented in the paper. Experimental studies were conducted to evaluate the impact of the structure and parameters of the system on dynamic properties of the engine. Bench tests were conducted on a diesel generator unit 1-PDG4D consisting of a diesel engine D50 and a traction generator MPT-84/39. As the result of the testing, equations describing dependencies of the transient process duration, overspeeding during the transient process and the free period on the parameters of the proportional-and-integral controller were obtained. The study confirmed the need to optimise the values of the coefficients of the proportional and integral components of the proportional-and-integral governing law and adjust them in accordance with the operational mode of the diesel engine. An appropriate optimisation method was proposed. Optimised values of these coefficients for the transient process of the studied diesel engine acceleration with regard to the locomotive characteristic were obtained.

scholarly journals Modelling and Recoupling the Control Loops in a Heavy-Duty Gas Turbine Plant

1995 ◽  
Author(s):  
G. Crosa ◽  
G. Ferrari ◽  
A. Trucco
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Linear Model ◽  
Transfer Functions ◽  
Heavy Duty ◽  
Turbine Plant ◽  
Exhaust Temperature ◽  
Non Linear ◽  
Gas Turbine Plant ◽  
Heavy Duty Gas Turbine

This paper presents a dynamic simulation of a single shaft heavy-duty gas turbine plant, suitable for gas-steam combined cycles. The plant is operated at maximum gas turbine exhaust temperature, using variable inlet guide vanes (VIGV) as control. In the first section, a non-linear lumped parameter mathematical model is described: it includes a control system representative of those controls normally utilised by industry today. Some dynamic responses of a controlled plant taken as an example are presented. In the second section, a different control system is proposed, operating with no interaction between the speed and exhaust temperature loops. To this aim, a linear model in the frequency domain of the uncontrolled plant is obtained, starting from the non-linear model in the time domain. Assuming that each one of manipulated variables influences only one of the controlled variables (VIGV only the exhaust gas temperature and the fuel mass rate only the load), the transfer functions of two new blocks have been obtained. To compensate for the system non linearity, the calculations are repeated for different load levels. The new control feature can offer advantages in the time response of the regulated plant, especially in the operating range where the airflow can be modulated by the VIGV at constant fuel firing temperature.

scholarly journals Active Control of Stiffness of Tensegrity Plate-like Structures Built with Simplex Modules

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7888
Author(s):  
Paulina Obara ◽  
Justyna Tomasik
Keyword(s):  
Stress State ◽  
Linear Model ◽  
Active Control ◽  
Static Behavior ◽  
Deployable Structures ◽  
Structural Concept ◽  
Non Linear ◽  
Stress States ◽  
Support Conditions ◽  
The Impact

The aim of this study is to prove that it is possible to control the static behavior of tensegrity plate-like structures. This possibility is very important, particularly in the case of deployable structures. Here, we analyze the impact the support conditions of the structure have on the existence of specific characteristics, such as self-stress states and infinitesimal mechanisms, and, consequently, on the active control. Plates built with Simplex modules are considered. Firstly, the presence of the specific characteristics is examined, and a classification is carried out. Next, the influence of the level of self-stress state on the behavior of structures is analyzed. A geometrically non-linear model, implemented in an original program, written in the Mathematica environment, is used. The results confirm the feasibility of the active control of stiffness of tensegrity plate-like structures characterized by the presence of infinitesimal mechanisms. In the case when mechanisms do not exist, structures are insensitive to the initial prestress level. It is possible to control the occurrence of mechanisms by changing the support conditions of the structure. Based on the obtained results, tensegrity is very promising structural concept, applicable in many areas, when conventional solutions are insufficient.

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