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Scheda Riassuntiva
Anno Accademico 2019/2020
Scuola Scuola di Ingegneria Industriale e dell'Informazione
Insegnamento 099245 - DYNAMICS AND CONTROL OF FLEXIBLE AIRCRAFT
Docente Masarati Pierangelo
Cfu 10.00 Tipo insegnamento Monodisciplinare

Corso di Studi Codice Piano di Studio preventivamente approvato Da (compreso) A (escluso) Insegnamento
Ing Ind - Inf (Mag.)(ord. 270) - BV (469) AERONAUTICAL ENGINEERING - INGEGNERIA AERONAUTICA*AZZZZ099245 - DYNAMICS AND CONTROL OF FLEXIBLE AIRCRAFT

Obiettivi dell'insegnamento

The course aims at providing a complete vision of the modeling of the dynamics of aeronautical structures, specifically of flexible aircraft, unifying the description of continuous and lumped parameter models, including the effect of unsteady, motion-dependent aerodynamic loads and the active control of vibrations, for loads reduction and stability augmentation, under the effect of deterministic and non-deterministic loads and disturbances.

A key aspect of the course is the study of the integrated modeling techniques that are required to address flexible structures subjected to free motion with non-structural problems, including thermal and aerodynamic ones, and their use for the realization of control systems.


Risultati di apprendimento attesi

Lectures are complemented by exercises, both guided and self-developed, occasionally accompanied by numerical solution of representative problems in appropriate mathematical computing environments. 

Students are expected to learn how to synthesize efficient structural models from detailed ones, formulate the corresponding unsteady aerodynamic loads, analyize the stability and the response of the resulting aeroelastic systems, prepare the models for the synthesis of control systems aimed at stability augmentation, and vibrations and loads attenuation.

At the same time, they are expected to familiarize with modeling and analysis techniques, to gain the capability to apply them to generic, multidisciplinary problems, understand the underlying physics, interpret the results in the context of analysis and design of complex aeroelastic systems.


Argomenti trattati

Definition of modal response problems:

-         Structural models, linear or linearized, either constrained or in unperturbed free average motion, with prescribed loads, including thermally induced ones

-         Fundamentals of structural damping modeling

-         General aspects of response problems using reduced modal models

-         Computation of free vibration modes, experimental verification and their importance

-         Computation of structural response up to structural verification, convergence of motion and stresses, truncation and residualization, acceleration modes, use of static modes

Numerical methods for the direct integration of the response on large models:

-         Response via direct integration, basic methods and their properties, stability, accuracy

-         Need of unconditional stability with algorithmic dissipation, comparison with modal response, pros and cons

-         Frequency domain solutions, limitations and critical aspects in terms of efficiency, some utilities

Response to non-deterministic inputs

-         Need for stochastic response analysis, typical aeronautical applications

-         General characterization of stochastic inputs, with specific reference to ergodic ones

-         Ergodic response of asymptotically stable problems using input-output relationships, in time and frequency domains, in state-space representation

-         Equivalent response indicators for design and structural verification

Reduced Order Models

-         Importance of efficient and effective reduced order models from large, detailed ones

-         Fundamentals of practical eigenanalysis

-         Generalization of modal reduction, reduction based on frequency content (slow and fast subsystems), need for modal space

-         Model reduction by truncation and residualization, quasi-steady models, time-frequency justification

-         State-space models: from the quadruple to the "decuple", model reduction, verification hierarchy

-         Modeling of sensors and actuators

Active control of aerospace structures

-          Optimal Control in state-space form (regulator): finite and infinite horizon, solvability conditions and solution, robustness (phase and gain margins) [or lack of it], rivisitation with optimization on some families of disturbances with "algebraic" approach

-          Need of state reconstruction, observer and its use as compensator

-          Design of steady optimal observer, “algebraic” approach, duality with controller

-          Loss of robustness of controller-observer

-          Spillover

-          Techniques for the selection of the cost functions and their connection with design requirements

-          Optimal control for direct measurement feedback, pros and cons

-          Order reduction of the controller based on frequency and balanced observability-detectability, fundamentals of digital implementation

Addition of configuration/motion dependent forcing terms (only linear or linearized):

-          Thermo-elastic coupling

-          Integrated coupling caused by motion-dependent boundary conditions

-          Aeroelastic coupling

-          Aerodynamic loads and their coupling with deformable structures

-          Unsteady aerodynamics linearized solution and its transformation in input-output relationship, in time and frequency domain

-          Direct input-output formulation using integral methods in frequency domain

-          Simplified aerodynamic models, lifting surface, airfoils and strip theory

-          Controls and servo-controls

-          Classic aeroelastic formulation (frequency domain) and its slow-fast hyerarchization

-          Deformable aircraft "trim"

-          Static aeroelasticity, main problems, simple examples: loads, response, structural verification, regulations

-          Dynamic aeroelasticity, flutter and response (deterministic and stochastic), solution techniques, regulations and structural verifications


Prerequisiti

- Virtual Work Principle

- Fundamentals of continuum mechanics and aerospace structures; bar, rod and beam models

- Finite Element Method

- Steady aerodynamics: strip theory, lifting line, lifting surface (numerical approximations: Doublet Lattice Method)

- Fundamentals of theory of system dynamics

- Fundamentals of control theory

- Fourier and Laplace transforms (including discrete Fourier transform)


Modalità di valutazione

Assessment: a written test followed by an oral examination, which must take place shortly after the written test. Examples of written tests will be discussed during the course; past exams are available on the course's Beep.  The oral discussion starts from an analysis of the written test.

 


Bibliografia
Risorsa bibliografica facoltativaBisplinghoff, Raymond L., Aeroelasticity , Anno edizione: 1996
Risorsa bibliografica facoltativaRodden, William P., Theoretical and computational aeroelasticity , Anno edizione: 2011
Risorsa bibliografica facoltativaDowell, Earl H., A modern course in aeroelasticity , Anno edizione: 2004
Risorsa bibliografica facoltativaHodges, Dewey H., Introduction to structural dynamics and aeroelasticity , Anno edizione: 2011
Risorsa bibliografica facoltativaFung, Yuan Cheng, The THEORY of AEROELASTICITY: An Introduction , Anno edizione: 1969
Risorsa bibliografica facoltativaBernard Friedland, Control System Design, Anno edizione: 1986
Risorsa bibliografica facoltativaRobert F. Stengel, Optimal Control and Estimation, Anno edizione: 1994

Software utilizzato
Nessun software richiesto

Forme didattiche
Tipo Forma Didattica Ore di attività svolte in aula
(hh:mm)
Ore di studio autonome
(hh:mm)
Lezione
60:00
90:00
Esercitazione
30:00
45:00
Laboratorio Informatico
10:00
15:00
Laboratorio Sperimentale
0:00
0:00
Laboratorio Di Progetto
0:00
0:00
Totale 100:00 150:00

Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua Inglese
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese
schedaincarico v. 1.7.2 / 1.7.2
Area Servizi ICT
05/07/2022