What are the three types of controlling?
In control theory, there are three types of controlling: Open Loop Control, Closed Loop Control, and Feedforward Control. Each of these types of controlling has its own characteristics, advantages, and disadvantages. Here is a more detailed explanation of each type of controlling:
- Open Loop Control:
Open Loop Control, also known as non-feedback control, is a simple control technique that does not use any feedback information from the system being controlled. In Open Loop Control, the control action is based on a predetermined set of rules, which are programmed into the controller. The control input is applied to the system, and the system output is measured or predicted. The controller adjusts the input based on the difference between the output and the setpoint. However, Open Loop Control does not have the ability to make any adjustments based on the system’s output. It is used when the system is simple, and the desired outcome is well known.
- Closed Loop Control:
Closed Loop Control, also known as feedback control, is a more sophisticated control technique that uses feedback information from the system being controlled to adjust the control input. In Closed Loop Control, a sensor measures the system output, which is compared to the setpoint, and the difference between the two is the error signal. The controller then adjusts the control input based on the error signal to reduce the error to zero. Closed Loop Control is more precise and adaptable than Open Loop Control since it can detect and correct any disturbances or changes in the system. It is used when the system is complex, and the desired outcome is not well known.
- Feedforward Control:
Feedforward Control is a control technique that anticipates the disturbances and adjusts the control input based on the anticipated disturbance, rather than waiting for the output to be measured. Feedforward Control predicts the future behavior of the system based on the knowledge of the input and system dynamics. It is used when the disturbance is known and predictable, and the system’s response can be estimated. It can improve the system’s stability and reduce the effect of the disturbance on the system output.
In summary, Open Loop Control is a simple control technique that does not use any feedback information, Closed Loop Control uses feedback information to adjust the control input, and Feedforward Control anticipates disturbances and adjusts the control input based on the anticipated disturbance. The selection of the control technique depends on the complexity of the system, the desired outcome, and the knowledge of the disturbance.