Core Feedback Concepts
How systems sense, decide, and act — and the domains and math used to describe them.
Feedback & Feedforward
Feedback control
Closes the loop by measuring behavior and correcting error.
Feedforward control
Acts from a model or known command before error appears.
Positive feedback
Reinforces deviations and appears in oscillators, switches, and biological regulation.
Feedback with logic
Combines continuous loops with modes, selectors, interlocks, and supervisory decisions.
Control-system architectures
Organize feedback, feedforward, estimation, optimization, and logic into layered designs.
Full-state feedback
Uses the entire state vector, often as u = -Kx, when states are measured or estimated.
Output feedback
Uses measured outputs directly or through an observer.
Separation principle
Designs state feedback and an observer separately for many linear output-feedback problems.
Compensator design
Combines controller and observer dynamics when the full state is not directly measured.