Feedbacksystem

A feedback system, or feedbacksystem, is a control mechanism that uses information about a system’s output to influence its input with the aim of achieving a desired behavior. Feedback is central to regulation in engineering, biology, economics, and everyday devices.

A typical closed-loop feedback system includes a sensor to measure the process output, a reference or setpoint that defines the target value, a controller that computes an input from the error between output and setpoint, and an actuator that applies the input to the process (the plant).

Feedback systems are typically contrasted with open-loop systems, which do not use output measurements to adjust their input. Closed-loop systems commonly rely on negative feedback to reduce error and stabilize performance; positive feedback can amplify deviations and may lead to instability or switch-like behavior.

Applications include home heating thermostats that maintain temperature, vehicle cruise control, and electronic amplifiers that use negative feedback to reduce distortion. In biology, feedback governs homeostasis and hormonal regulation. In software and organizational practice, feedback loops support iterative learning and improvement.

Key design considerations include achieving adequate stability, fast and accurate response, robustness to disturbances, and minimization of noise and actuator saturation. Common control methods include PID (proportional-integral-derivative) controllers, model-based designs, and adaptive schemes that adjust parameters in real time.

Limitations include time delays, measurement noise, nonlinearities, and resource constraints. Proper design, testing, and safety margins are essential to prevent instability or unsafe operation. The term feedbacksystem is widely used in German-speaking regions to describe such control loops.