Catalog description
Mathematical modeling of automatic control systems. Open-loop and
closed-loop control. Laplace transform techniques and transfer functions.
Stability. Root locus technique, Bode plots, Nyquist criterion.
Approaches to control system design, including PID and lead-lag
compensation.
Prerequisite: ME 390 or consent of instructor.
Who takes it
Automatic feedback control systems are ubiquitous, arising in electrical,
mechanical, biological, ecological, nuclear, and economic systems.
This course should be taken by anyone interested in modeling and
design of control systems.
What it's about
Control systems use sensors to measure the state of a system and
produce controls to make the system behave in a desired way. Examples
of control systems are cruise control, autopilot systems, and robot
controllers. In this course we focus on the design of control systems
with a single controlled output (such as the speed of the car in
cruise control) and a single control input (such as the angle of
the accelerometer pedal).
Learning Objectives:
- Upon completion of ME 391 students should have learned about
analysis and design of feedback controllers for linear single-input
single-output dynamic systems.Specifically:
- The usefulness of feedback control for disturbance rejection
and stabilization.
- Laplace transforms and transfer functions.
- Block diagram representations of feedback control systems.
- Impulse and step responses of second-order dynamic systems.
- The meaning of performance specifications such as maximum
overshoot, settling time, and steady-state error.
- The relationship between the location of system poles and
zeros and system performance.
- Proportional, integral, and derivative (PID) control, and
how each affects performance.
- Stability and the Routh-Hurwitz stability criterion.
- The root locus method of control system analysis, and how
to place a controller pole and zero to improve performance
(lead-lag compensation).
- Gain and phase (stability) margins from the Bode magnitude
and phase plots of the frequency response.
Performance Objectives
- Upon completion of ME 391 students should be able to:
- Model physical (masses, springs, and dampers) and electrical
(capacitors, resistors, and inductors) systems and derive
their transfer functions.
- Read off performance parameters from a step response.
- Understand qualitatively how changing P, I, and D control
gains will affect the step response of a second-order system.
- Determine the stability of a transfer function.
- Sketch a root locus.
- Interpret a transfer function, step response, pole-zero
plot, or Bode plot and choose (or modify) a controller to
improve performance.
Experiences
- Upon completion of ME 391 students should have completed the
following experiences:
- Used MATLAB to help analyze dynamic systems and design feedback
controllers.
- Implemented PD and PID control on an experimental torsional
disk (mass-spring-damper) system and collected step response
data.
- Implemented a lead-lag controller on the torsional disk
system.
- Experimentally derived the frequency response of the torsional
disk system.
Labs :
In general students work on their lab projects in teams of two
or three, for an entire length of each three hour long session.
Lab hours will be scheduled during the first week of class.
Assessment/Evaluation:
Lab reports. Weekly problem sets. Two quizzes. A midterm and
a final. All exams will be open book, and you will also be allowed
to bring study sheets.
Textbook :
Feedback Control of Dynamic Systems,
4th edition, by Franklin, Powell, and Emami-Naeini,
ISBN 0-13-032393-4.
Contact:
Professor: Kevin Lynch
e-mail: kmlynch@northwestern.edu
[ Course
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