Final answer:
An integral control strategy corrects the process-variable offset/steady state error in a control system by integrating the error over time and adjusting the controller's output.
Step-by-step explanation:
An integral (Ki or Ti) control strategy is a method of correcting the process-variable offset/steady state error by a controller output. The integral component of a PID controller is responsible for eliminating the steady-state error that can occur with a pure proportional controller. It effectively integrates the error over time and adds a corrective factor to the output, which adjusts until the error is reduced to zero, thereby ensuring the process variable reaches and stays at the setpoint value.