Chapter 7 · Watch, then practise
Control System
Close the loop between measurement and actuation and distinguish the three contributions of a PID controller.
3 questions · 3 with related videos. Matches are based on playlist titles; broader background matches are labeled.
What to study
- Setpoint, measurement and error
- Feedback control
- Proportional, integral and derivative terms
- Response and tuning
Chapter playlists
Existing playlist: Control System
Notes
Closed Loop Systems
Neso Academy · 4:55
Closed-loop systems are the matching feedback-control concept.
1. Feedback loop
What makes a controller closed loop?
It measures the controlled output, compares it with the setpoint and adjusts an actuator using the resulting error. For temperature control, the sensor closes the loop around heater and room. An open-loop heater command does not correct itself from measured temperature.
What is a PID Controller?
RealPars · 5:39
Choose a video · 2 lectures
The PID introduction and controller comparison support interpreting the proportional, integral and derivative terms.
2. PID equation
What do the terms in u(t) = Kp e(t) + Ki ∫e(t)dt + Kd de(t)/dt do?
The proportional term responds to current error. The integral term accumulates error and can remove persistent offset. The derivative term responds to error’s rate of change. Gains change the response; aggressive tuning can increase overshoot or instability, and derivative action is sensitive to measurement noise.
P, PI, PD, and PID Controllers: A Comparative Analysis in Control System Engineering
Engineering Funda · 11:36
The controller comparison is relevant to response assessment; use the written definitions for the requested performance measures.
3. Assess the response
Which measurements help compare two controller tunings?
Compare rise time, overshoot, settling time and steady-state error under the same test conditions. A faster initial response may overshoot more. In software, use a defined sampling interval and account for actuator limits; a visually quick response alone is not evidence of good control.