What is hunting in a control system?
What is Hunting in a Control System?
Hunting in a control system means that the system keeps moving back and forth or overcorrecting itself around its setpoint. In other words, a control system that keeps going too high or too low, such a temperature, pressure, or speed controller, is “hunting.” This arises because the system doesn’t attain a stable state because it reacts too quickly or too slowly to changes.
Hunting can be seen in different systems in real life. In HVAC systems, for instance, it looks like the temperature in the room is constantly changing around the thermostat setting. In industrial process control, it can make pressure or flow data constantly go up and down near the intended value.
Hunting is typically caused by bad tuning of the controller (particularly in PID loops), bad quality of the feedback signal, wrong location of the sensor, and not enough damping in the system. If the feedback response is too fast or too sensitive, the system keeps correcting itself in both directions, which causes oscillations.
Hunting is bad because it wastes energy, causes actuators or valves to wear out faster, makes processes less stable, and makes products of lower quality.
Engineers utilize damping devices, carefully tune PID parameters, and include a deadband or hysteresis at the setpoint to reduce hunting. Tuning the control loop correctly makes sure that it responds smoothly and gets to the right value without any oscillation.
Hunting is a sign of instability in a control system, although it can be reduced by careful tuning, dampening, and judicious sensor placement.