To avoid the problems of the open-loop controller, control theory introduces feedback.

The hardware provided no way for the software to verify that sensors were working correctly (see open-loop controller).

An open-loop controller is often used in simple processes because of its simplicity and low cost, especially in systems where feedback is not critical.

Closed-loop controllers have the following advantages over open-loop controllers:

A characteristic of the open-loop controller is that it does not use feedback to determine if its output has achieved the desired goal of the input.

However, during the expiratory phase, the expiratory flow can be commanded by an open-loop controller or a closed-loop controller:

This type of controller is called an open-loop controller because no measurement of the system output (the car's speed) is used to alter the control (the throttle position.)

Controllers for brushed motors however are much simpler and cheaper due to the fact they don't require hall sensor feedback and are typically designed to be open-loop controllers.

If the hardware open-loop controller provides linear ramped acceleration, /deceleration, find the optimum stepping rate limit and Corresponding ramp gradient to minimise the time taken to move 50 steps.

The motor's position can then be commanded to move and hold at one of these steps without any feedback sensor (an open-loop controller), as long as the motor is carefully sized to the application.

An open-loop controller, also called a non-feedback controller, is a type of controller that computes its input into a system using only the current state and its model of the system.

The MAF sensor provides the open-loop controller predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.

If the load were not predictable, on the other hand, the motor's speed might vary as a function of the load as well as of the voltage, and an open-loop controller would therefore be insufficient to ensure repeatable control of the velocity.