Control Systems

Module aims

  • To provide students with the fundamental concepts in the analysis and design of automatic control systems for use in a wide range of technologies (not just Aeronautics, but also Mechanical Engineering, Electrical Engineering, Chemical Engineering, Finance, Biology, etc.)
  • To introduce some applications of control systems in the aerospace industry.
  • To provide a framework and language to communicate with professional control engineers in their terms about control issues.
  • To introduce the student to using industry-standard software, such as Matlab and Simulink, for control system analysis and design.

Learning outcomes

Knowledge and understanding: 
On successfully completing this course unit, students will be able to:
  • Give examples of feedback in dynamical systems and discuss some of the basic properties of a feedback system.
  • Convert an ODE of a dynamical system into alternative, but equivalent forms, such as the state space and transfer function form.
  • Compute the equilibrium points of a nonlinear system and classify their stability properties.
  • Compute a linear approximation of a nonlinear system about an equilibrium point.
  • Design an output feedback controller for a linear system using pole placement and the separation principle.
  • Design a proportional-integral-derivative (PID) controller.
  • Analyse and predict the closed-loop stability from open-loop Nyquist and Bode plots.
  • Design and analyse the performance of a controller for a linear system in the frequency domain or using the root locus.
Skills and other attributes: 
On successfully completing this course unit, students should be able to:
 
Intellectual skills
  • Assimilate and apply the basic principles of control theory on a range of engineering and non-engineering applications.
  • Formulate design specifications for a control system.
  • Assess and discuss the trade-offs that have to be made in a control design.
  • Evaluate the performance of a control system.
  • Modify an existing control design in order to meet design specifications.
  • Critically analyse and discuss the results obtained from a control experiment.
Practical skills
  • Design and implement a controller on a laboratory experiment using Matlab and Simulink. 
Transferable skills
  • Develop independence in studying and manage their time in order to meet deadlines.
  • Use self-assessment to monitor their ability to learn and apply new material.
  • Collaborate with peers outside lecture hours in order to master the course material.
  • Make their own course notes from attending lectures.
  • Locate, extract and assimilate additional material from a variety of references, such as books and web-based sources, to supplement course notes.
  • Collaborate in small groups during tutorial classes in order to solve problems.
  • Write a report on the design process followed during a control experiment.

Module syllabus

  • Introduction: Examples and properties of feedback, simple forms of feedback.
  • System Modelling: Modelling concepts, state space models, block diagrams, input-output models. Examples from aerodynamics, aerostructures, flight mechanics, astronautics.
  • Dynamic Behaviour: Solving differential equations, phase portraits, equilibrium points, stability.
  • Linear Systems: Definition of a linear system, convolution, stability and performance, second order systems, linearization.
  • State Feedback: Reachability, stabilization by state feedback, design issues.
  • Output Feedback: Static and dynamic output feedback, observability, state estimation, control using estimated state, separation principle.
  • Transfer Functions: Laplace transforms, definition of the transfer function, block diagrams of complex systems, pole and zero locations, stability, the Final Value Theorem.
  • Frequency Response and Bode Diagrams: frequency domain analysis, Bode plots.
  • Simple Feedback Systems: PID Control: Closed loop characteristic equation, PID controllers.
  • Feedback Systems: Stability and Performance: Nyquist plots, Nyquist's stability criterion, gain margin and phase margin, sensitivity function, feedback design via loop shaping, lead/lag compensation.
  • Root Locus Techniques: Basic methods for sketching the root locus, introduction to root locus design.

Pre-requisites

AERO50002 Flight Dynamics and Control
AERO50003 Computing and Numerical Methods 2
AERO50006 Mathematics 2
AERO50007 Mechatronics 
AERO50008 Structures 2

Teaching methods

Lectures/Tutorials
Lectures, tutorial classes, surgery/revision class

Laboratory exercises
The Twin Rotor Multivariable System: Feedback control of a pseudo-helicopter

Assessments

Examined Assessment:
1.5 hour written examination in Summer Term (65%),
a series of online coursework assignments & laboratory (35%)

Non-Examined Assessment

Blackboard quizzes

Reading list

Core

Supplementary