18-879 PR/T: Nonlinear Control Systems

IST/CMU PhD Course - Springer Semester 2011

 

 

  Software: Microsoft Office

Computer simulation of an autonomous underwater vehicle following a desired 3D trajectory 

Announcements

Posted on April 12, 2011

The slides of part “10 – Adaptive nonlinear control (a simple example)” can be downloaded here [Slides#10].

 

Posted on April 12, 2011

The slides of part “9 – Advanced Stability Analysis” can be downloaded here [Slides#9].

Homework #11 can be downloaded here [HW#11].

 

Posted on March 31, 2011

The last version of part “8 – Passivity” can be downloaded here [Slides#8_v3].

Homework #10 can be downloaded here [HW#10].

 

Posted on March 31, 2011

The second version of part “8 – Passivity” can be downloaded here [Slides#8_v2].

Homework #9 can be downloaded here [HW#9].

 

Posted on March 24, 2011

The last version of the slides of part “7 – Feedback Linearization” and the first version of part “8 – Passivity” can be downloaded here [Slides#7_v4], [Slides#8_v1].

 

Posted on March 22, 2011

The third version of the slides of part “7 – Feedback Linearization” can be downloaded here [Slides#7_v3].

Homework #8 can be downloaded here [HW#8].

 

Posted on March 17, 2011

The second version of the slides of part “7 – Feedback Linearization” can be downloaded here [Slides#7_v2].

 

Posted on March 15, 2011

The first set of slides of part “7 – Feedback Linearization” can be downloaded here [Slides#7_v1].

 

Posted on March 3, 2011

The slides about a Lyapunov based design control law for a Hovercraft can be downloaded here [Slides#6_Hovercraft].

 

Posted on March 3, 2011

Homeworks #6 and #7 can be downloaded here [HW#6] [HW#7].

The due date of both homeworks is Tuesday, March 15th.

 

Posted on February 28, 2011

The second version of part “6 - Nonlinear Design” can be downloaded here [Slides#6_v2].

 

Posted on February 21, 2011

The first set of slides of part “6 - Nonlinear Design” can be downloaded here [Slides#6_v1].

 

Posted on February 20, 2011

The 24h take home exam will be on April 28th.

Regarding the project, the following two types of projects are possible in this course:

1. Solution of a research problem relevant to the student’s area of research, which makes use of methods described in the course.

2. Independent study of a topic not covered in-depth in class (e.g., reading a paper or book chapter).

If you need suggestions just come to speak with me or Sergio.

You should define a project no longer than March 18th. Please send an email to me and Sergio describing what you plan to do.

The final presentation is required in class during the days 3 and 5 of May and they should have a maximum of 8 minutes + 2 min. of questions that can arise from me, Sergio or your colleagues.

You should deliver on the day of your presentation a final report no longer then 5 pages plus a copy of the slides of your presentation.

 

Posted on February 20, 2011

The homework #5 [HW#5] has been posted online.

The due date is Tuesday, March 1st.

 

Posted on February 14, 2011

The slides of  “5- Input-Output Stability” can be downloaded here [Slides#5].

 

Posted on February 12, 2011

The due date of homework #4 [HW#4] has been postponed to February 22nd.

 

Posted on January 31, 2011

The last version of part “4- Lyapunov Stability” can be downloaded here [Slides#4_v4].

 

Posted on February 1, 2011

The homework #3 [HW#3] has been posted online.

The due date is next Tuesday (Feb. 8th).

 

Posted on January 31, 2011

Version 3 of part “4- Lyapunov Stability” can be downloaded here [Slides#4_v3].

 

Posted on January 26, 2011

Version 2 of part “4- Lyapunov Stability” can be downloaded here [Slides#4_v2].

 

Posted on January 25, 2011

The homework #2 [HW#2] has been posted online.

The due date is next Tuesday (Feb. 1st).

 

Posted on January 19, 2011

The first 28 slides of part “4- Lyapunov Stability” can be downloaded here [Slides#4].

 

Posted on January 18, 2011

The homework #1 [HW#1] has been posted online.

The due date is next Tuesday (Jan. 25).

 

Posted on January 16, 2011

The third part “3- Fundamental properties” can be downloaded here [Slides#3].

 

Posted on January 12, 2011

The second part “2- Mathematical review” can be downloaded here [Slides#2].

 

Posted on January 11, 2011

The slides of chapter “1- Introduction to Nonlinear Systems” can be downloaded here [Slides#1].

 

Posted on January 5, 2011

Schedule: (First lecture: Tuesday, January 11, 2011)

      Tuesday                       14:00 – 15:30 (Lisbon time)                9:00 – 10:30 (Pittsburgh time)            

      Thursday          14:00 – 15:30 (Lisbon time)                9:00 – 10:30 (Pittsburgh time)

Location:

IST: Institute for Systems and Robotics (ISR)Videoconference Room, 7th floor, North Tower, IST.

CMU: INI building, Henry Street.

 

 

Objective

The main goal of this course is to provide to the students a solid background in analysis and design of nonlinear control systems.

 

Course Description

Many control systems of practical importance are inherently nonlinear. A common practice for control system design is to linearize the system to be controlled around some equilibrium or operating point through small perturbation state approximations. The key assumption is that the range of operation is restricted to a small region around the equilibrium on which the linear model remains valid. As a consequence, adequate control is only guaranteed in a neighborhood of the selected operating points. Moreover, performance can suffer significantly when the required operating range is large, such as when controlling an autonomous vehicle that executes maneuvers that emphasize its nonlinearity and cross-couplings.

 

This course covers the analysis and design of nonlinear control systems and is suitable for post-graduate students in science and engineering. The course begins with an introduction to nonlinear system theory and stability analysis. Topics include Lyapunov stability analysis techniques, stability of perturbed systems with vanishing and non-vanishing perturbations, input-to-state stability, input-output stability and passivity. The last part of the course is dedicated to nonlinear control design tools such as feedback linearization, sliding mode control, Lyapunov redesign, backstepping, passivity based control and nonlinear adaptive control (if time permits). Emphasis is placed upon application of the theory to systems of interest to the students.

 

 

Prerequisites

Basic knowledge of calculus, linear algebra and ordinary differential equations is assumed.

 

Class Schedule

Tuesdays and Thursdays, 9 a.m.-10:30 a.m.

 

Course Personnel

Instructor:

·      Antonio Pedro Aguiar

Office: 8.13, North Tower, IST, Lisbon

Phone: +351 21 841 8056

Email:    pedro@isr.ist.utl.pt

Web: http://users.isr.ist.utl.pt/~pedro/

Office Hours: Please email or phone in advance to schedule an appointment.

 

Teaching Assistants:

·      Sérgio Daniel Pequito

Office: B21 (Potter Hall)

Phone:

Email:    spequito@andrew.cmu.edu

Office Hours: Please email or phone in advance to schedule an appointment.

 

Course Management Assistant:

·      Bara Ammoura

Hamerschalg Hall D200

412-268-6595

bammoura@ece.cmu.edu

Office Hours: Monday-Friday, 8:30 a.m.-5:00p.m.

 

Textbook

Khalil, H. K. Nonlinear Systems, 3rd Edition, Prentice Hall, Upper Saddle River, NJ, 2002.

 

Grading Policy

Homeworks – 30%

Final Project – 40%

Final Exam  – 30% (24h take home)

 

Projects

The following two types of projects are possible in this course:

  1. Solution of a research problem relevant to the student’s area of research, which makes use of methods described in the course.
  2. Independent study of a topic not covered in-depth in class (e.g., reading a paper or book chapter).

 

Course Topics

1.   Introduction to nonlinear systems

         Nonlinear systems vs. linear systems, multiple isolated equilibrium points, finite escape times, limit cycles.

2.   Mathematical preliminaries

         Normed vector spaces. Induced norms. Mean value and implicit function theorems. Gronwall-Bellman inequality. Lipschitz condition.

3.   Fundamental properties        

         Local and global existence and uniqueness of solutions. Continuity with respect to initial conditions. Comparison Principle.

4.   Lyapunov Stability

        Autonomous Systems. The Invariance Principle. Linear Systems and Linearization. Comparison Functions. Nonautonomous Systems. Linear Time-Varying Systems and Linearization. Converse Theorems. Boundedness and Ultimate Boundedness. Input-to-State Stability.

5.   Input–Output Stability

         L Stability. L Stability of State Models. L2 Gain. Feedback Systems: The Small-Gain Theorem

6.   Passivity

         Memoryless Functions. State Models. Positive Real Transfer Functions. L2 and Lyapunov Stability. Feedback Systems: Passivity Theorems.

7.   Frequency Domain Analysis of Feedback Systems

         Absolute Stability: Circle Criterion, Popov Criterion.

8.   Advanced Stability Analysis

         The Center Manifold Theorem. Region of Attraction. Invariance-like Theorems. Stability of Periodic Solutions

9.   Stability of Perturbed Systems

         Vanishing Perturbation. Nonvanishing Perturbation. Comparison Method.

10. Feedback Linearization

         Motivation. Input–Output Linearization. Full-State Linearization. State Feedback Control. Stabilization. Tracking.

11. Nonlinear Design Tools

        Sliding Mode Control: Motivating Example, Stabilization, Tracking, Regulation via Integral Control. Lyapunov Redesign: Stabilization, Nonlinear Damping. Backstepping. Passivity-Based Control. Basic nonlinear adaptive control design.

 

 

Tentative Course Calendar

 


Date

Day

Class Activity

January

11

T

Introduction to Nonlinear systems. Examples

13

T

Second-order systems and qualitative behavior near equilibrium points

18

T

Mathematical Review

20

T

Fundamental properties of dynamical systems

25

T

Lyapunov stability for Autonomous Systems

27

T

Region of attraction. La Salle’s Theorem

February                     

1

T

Linear Systems and Linearization. Comparison Functions.

3

T

Nonautonomous Systems. Linear Time-Varying Systems and Linearization.

8

T

Converse Theorems. Boundedness and Ultimate Boundedness.

10

T

Input-to-State Stability. Small gain theorem

15

T

Input–Output Stability.            L Stability. L Stability of State Models. L2 Gain.

17

T

Feedback Systems: The Small-Gain Theorem

22

T

Nonlinear Design Tools: Sliding Mode control

24

T

Sliding mode control: regulation via integral control

March

1

T

Lyapunov Redesign: Stabilization. Nonlinear Damping

3

T

Backstepping. Nonlinear control project example

8

T

Spring Break – No Class

10

T

Spring Break – No Class

15

T

Feedback Linearization. Input-output linearization

17

T

Full state linearization

22

T

State-feedback control. Stabilization. Tracking

24

T

Passivity: Memoryless Functions. State Models. Positive Real Transfer Functions.

29

T

L2 and Lyapunov Stability. KYP lemma Feedback Systems: Passivity Theorems.

31

T

Passivity-based control

April

5

T

Perturbation theory and averaging

7

T

Periodic perturbation of autonomous systems

12

T

Weakly nonlinear second-order oscillators

14

T

General averaging

19

T

Basic nonlinear adaptive control design.

21

T

IST Easter break – No Class

26

T

IST Easter break – No Class

28

T

24h take home exam

May

3

T

Final Examinations

5

T

Final Examinations

10

T

Final Examinations