Control Systems
Feedback is the idea that measuring the output and subtracting it from the input can beat any amount of careful calibration. These topics run the loop and show the error shrink, oscillate, or run away.
Start from the beginning →1 topic you can watch now, 23 still to come.
Foundations
What feedback buys, and what it costs.
- Modelling electrical and mechanical systems
- Transfer functions
- Block diagram reduction
- Signal flow graphs and Mason's rule
Time response
How the output gets to where it was told to go.
- First-order response
- Second-order response: damping ratio and natural frequency
- Rise time, peak overshoot and settling time
- Steady-state error and system type
Stability
Whether the loop settles at all, decided before it is built.
- The concept of stability and pole locations
- Routh-Hurwitz criterion
- Root locus construction
- Effect of adding poles and zeros
Frequency response
Poke the system with every frequency and listen to the answer.
- Bode plots
- Gain margin and phase margin
- Polar plots and the Nyquist criterion
- Nichols chart and closed-loop response
Compensator design
Changing the loop until it behaves the way the spec demands.
- Lead, lag and lead-lag compensators
- P, PI, PD and PID controllers
- Ziegler-Nichols tuning
State-space analysis
The same system written as first-order equations in a vector.
- State variables and state models
- State transition matrix
- Controllability and observability
- Pole placement by state feedback