Control theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems with inputs, and how their behavior is modified by feedback [1].

The objective of control theory is to design a controller so that the system has some desired characteristics. Typical objectives are [2]:

  • Stabilization
  • Regulation
  • Tracking
  • Disturbance rejection

Feedback Control Approach

  1. Establish control objectives
    • Qualitative
    • Quantitative: step response time
    • Require understanding of expected commands, disturbances and bandwitdh
    • Require understanding of physical dynamics and appropriate control method
  2. Select sensors and actuators
    • What aspect to be sensed and controlled?
    • Sensor noise, cost, reliability, size ...
  3. Obtain system model
    • First principle or system identification
    • Evaluation model -> reduce size and complexity
    • Accuracy? Error model?
  4. Design controller
    • SISO or MIMO?
    • Classical or state-space?
    • Choose parameters (rule-of-thumb or optimization)
  5. Analyze closed-loop performance
    • Does closed loop meet objectives?
    • Analysis, simulation, experimentation and iterate.


This document includes basic descriptions and implementations of a Control System. The materials covered are: system modelling, controller design, classical control theory, modern control theory and C/Matlab/Simulink implementations.

This wiki site is maintained by myself at an irregularly base. Contents might be inconsistent when I am working on them. Please use it with caution as I assume no other user than myself would be using this website.


  1. Control Theory - Wikipedia, link
  2. Jonathan How, and Emilio Frazzoli. 16.30 Feedback Control Systems. Fall 2010. Massachusetts Institute of Technology: MIT OpenCourseWare, License: Creative Commons BY-NC-SA.