säätövirhe

Säätövirhe, often translated as control error or regulation error, is a fundamental concept in control theory. It refers to the difference between the desired value of a system, known as the setpoint or reference value, and the actual measured value of the system's output. In essence, it quantifies how far the system's performance deviates from the target.

Control systems are designed to minimize or eliminate this säätövirhe. A control system continuously monitors the system's output and compares it to the setpoint. If a discrepancy is detected, the controller generates a corrective action to bring the output closer to the desired value. For example, in a thermostat controlling room temperature, the setpoint is the desired temperature, and the actual measured temperature is the system's output. The säätövirhe is the difference between these two values. The thermostat then activates the heating or cooling system to reduce this error.

The presence and magnitude of säätövirhe can be influenced by various factors, including system disturbances, sensor noise, actuator limitations, and the design of the controller itself. Different types of controllers, such as proportional (P), proportional-integral (PI), and proportional-integral-derivative (PID) controllers, are employed to manage and reduce säätövirhe in different applications. The goal of effective control is often to achieve zero steady-state säätövirhe, meaning that the system's output eventually matches the setpoint over time.