What component is primarily adjusted in a PID controller to influence the system's steady-state error?

• A. Proportional gain
• B. Integral gain
• C. Derivative gain
• D. All of the above

Answer: (B)

In a PID (Proportional-Integral-Derivative) controller, the integral gain is primarily adjusted to influence the system's steady-state error. The steady-state error represents the difference between the desired setpoint and the actual output after the transients have settled.

The integral component of the PID controller specifically addresses accumulated past errors over time. By integrating the error signal, it effectively sums up all past errors, which allows the controller to apply a correction that will eliminate the steady-state offset. When the integral gain is increased, the controller responds more aggressively to any persistent errors, leading to a rapid reduction of the steady-state error.

In contrast, while the proportional gain can reduce the overall error and improve response, it may not eliminate steady-state errors, especially in the presence of constant disturbances or system bias. The derivative gain anticipates future errors based on the rate of change of the error and helps in damping the system's response, but it does not directly correct steady-state errors. Thus, the integral gain is the crucial factor for addressing and eliminating steady-state errors effectively.