What is a steady-state error in a control system?

Steady-state error occurs due to various factors, such as system dynamics, disturbances, and controller limitations. It is influenced by the type of control system (e.g., proportional, integral, derivative) and the characteristics of the input and output signals.

The steady-state error is typically analyzed in response to a step, ramp, or sinusoidal input signal. Different types of steady-state errors can be observed, including:

Positional error: This refers to the difference between the desired output and the steady-state output when the input signal is constant. It indicates the system's ability to reach the desired position or maintain a specific output value.

Velocity error: This is the difference between the desired output and the steady-state output when the input signal is changing at a constant rate (e.g., a ramp input). It measures the system's ability to track changes in the input signal over time.

Acceleration error: This represents the difference between the desired output and the steady-state output when the input signal is changing at a constant acceleration (e.g., a sinusoidal input). It reflects the system's ability to accurately respond to rapidly changing input signals.

The goal in control system design is to minimize steady-state error to achieve accurate tracking of the desired reference signal. This can be achieved through appropriate selection and tuning of control system parameters, such as proportional, integral, and derivative gains, as well as by employing advanced control techniques.