Demonstrate knowledge about the systems design process and understand the role and the importance of the systems modelling, simulation and testing activities application along the design phases. Ability to create non linear models of different components of a typical aerospace control system. Ability to integrate low hierarchy models to define a more complex multidisciplinary model of a system by the use of commercial programming tools. Ability to understand how models can (regardless of their design value) also be integrated on board a system to implement diagnostic and prognostic functions. Demonstrate knowledge and understanding about laboratory testing activity, managing control laws. Ability to conduct simple experiments on a laboratory workbench, carrying out test activities.

The prerequisite for the course is the basic knowledge of physics, mechanics, hydraulics, electro-technics and automatic controls.

General part Basics of model theory and time domain numerical simulation of lumped parameter systems techniques. System design engineering and role played by modelling, simulation and testing. "V"-model of Systems Engineering: needs identification, requirements formulation, concept generation and selection, trade studies, preliminary and detailed design; definition of component and subsystem test plan and integration, as well as functional verification testing. Types of nonlinearities of servo-mechanisms. Primary flight controls description, with special reference to fly-by-wire architectures integrating Electro Hydrostatic and Electro Mechanical Actuators (EHA and EMA). Basics of safety and reliability in systems design. Fault tolerant architectures for primary flight controls. Diagnostics and prognostics techniques in safety critical control systems. Application of numerical simulation on nonlinear servo-mechanism. General programming techniques for the non-linear numerical simulation starting from the existing sub-systems models; analysis and comparison between different approaches. Trade-off analysis between dynamical models, with different typology and complexity, of a specific component or sub-system. Relevant applications of aerospace dynamic systems. Commercial tools and techniques for system simulation. Analysis of the numerical problems of time domain simulation. Outline of multidisciplinary integrated design techniques: concurrent e simultaneous engineering (SE). Outline of the multidisciplinary design system optimization (MDSO) methodology. Generality of aerospace systems testing. Workbench and sensors calibration. Design of experiments techniques. Testing equipment and sensors integration. Application part Modelling of flight controls components; 1) electro-mechanical parts: DC motor, variable displacement hydraulic pumps, screw jacks, hydraulic cylinders, flight control surfaces and mechanic links, 2) control and regulation parts: hydraulic servo-valves, relief valves, sensors, position control loop algorithms. Several models for each components will be developed with increasing level of complexity, including non-linear effects (clearances, coulomb friction, saturations, hysteresis, etc..). Complete electro-fluid-dynamic model of a servo-valve with fourth and third orders formulation. Possible simplification to the first order and instantaneous formulation. Pros and cons comparison. High lift device actuation unit modelling: hydraulic motor + fail safe transmission torsion shaft + linear actuators + no back brakes. Complete electro-fluid-dynamic model of a servo-valve + hydraulic cylinder with a position control loop: sixth and fifth order formulation. Simplification to the orders 3 and 2; pros and cons comparison. Two stages electro-hydraulic servo-valves: spool as a second stage; types of first stage piloting control loop: flapper-nozzle, jet-pipe, jet-deflector. Working principles jet-pipe and comparisons with the other types. Description of the classical dynamic behaviour during the interaction of the two stages of the valve. Analysis of the effects of the model simplifications on the actuation time constants. Integration of the aforesaid models into a complete actuation system of a fly-by-wire control, aircraft flight mechanics included. Parametric analysis of the numerical behaviour of the developed models when simulating. Definition of figures of merit to characterize the performance of the system model with respect of the design requirements. Definition of a testing plan to be implemented on the experiments workbench. Implementation of diagnostic logics, failure management criteria and fault tolerance characteristics. Definition of a simple case study of multidisciplinary design optimization applied to a primary flight control.

The course consists of lectures interspersed with hands-on practice (at least 40% of the total number of hours for the course). followed by exercises, based on the material covered in the lecture, with the continuous support of the teacher. The exercises are conducted in the computer laboratory by the use of Matlab-Simulink tool. Several non-linear models of different types of recent aerospace servo-mechanisms (mainly primary flight controls) are developed by the student under the teacher guide. The simulation results are discussed and compared. They are collected on a student’s individual project report to be discussed at the final exam. Practical exercises are also provided by a laboratory workbench representing a modern fly-by-wire primary flight controls scheme, with a position loop computer having a parametric gain settings unit, and a dedicated data acquisition board.

None are required, as a complete digital set of the lecture notes and laboratory examples, to download from the course web page, will be provided. The following textbooks provide optional resource material for this course: 1) Dean C. Karnopp, Donald L. Margolis, Ronald C. Rosenberg, "System Dynamics: Modeling and Simulation of Mechatronic Systems", 4th Edition Wiley, 2006. 2) MIL-STD-810G, Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests. 3) Garret N. Vanderplaats, "Numerical Optimization Techniques for Engineering Design", ISBN 0-944956-01-7, 3rd Edition, Vanderplaats Research & Development Inc., 2001.

Exam: Compulsory oral exam; Individual essay;

The student will be personally supervised by the teachers during the exercises during the year, verifying the adequate knowledge of the methodological and applicative aspects taught during the course and the ability to use this knowledge to interpret, describe in multidisciplinary terms some problems related to the subject, with particular emphasis on primary flight controls and on electromechanical drives in general. The oral examination will focus on all the topics of the course and, in particular, on the presentation of the reports of the exercises. The exam will also verify the maturity of the student and his ability to relate disciplines and heterogeneous phenomena. The presentation during the examination of the reports of all the exercises, in personal copy, is a necessary condition to access the exam itself; part of the evaluation will be based on the correct understanding of the meaning and on the clarity and order of these reports.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.