Feedback Control system and Feedforward

Control system

In a Company or a business, it is very important to plan and work according to the plan, so we can get the desired outcome or profit for the business. For the planning purpose different processes are used. Feedback control system and Feedforward system are also like those processes. With the help of the Feedback control system and Feedforward system, we can plan the steps that are needed to implement by a company or the business. So, in this article, we are going to know about the Feedback control system and Feedforward control system briefly and know their advantages and disadvantages.

Feedback Control System

Feedback control system is one of the most popular techniques which is widely used in the process planning of an industry or a business. In the Feedback control system, it always compares the actual outputs with the planned outputs or expected outputs. If the actual outputs and planned outputs are not close enough, then the subsequent action is taken to find the outcomes that are close to the planned outputs. In the Feedback control system, we have positive feedback and negative feedback the help in better understanding the problems and improve the accuracy of the outputs.

Positive Feedback

Positive feedback is given when the achieved output is more efficient and accurate than the desired output or expected output. The Positive feedback is only given when the output exceeds our expectations. When we get positive feedback there is no need of further investigation and any changes should be done in the process or steps that we are already implemented. There is no need of reducing the likelihood of the repetition of the process.

Negative Feedback

Negative feedback will be given when the output achieved by the process will be below our expectations and the output does not get close to the expected output. When we get negative feedback, we should investigate all the steps of the plan. After finding steps that are responsible for negative feedback should be changed. By the help of negative feedback, we can reduce the steps and change them as required.

Feedforward Control System

Feedforward control system is a concept in which all the important disturbance variables are present and makes the corrections required in the plan to run the process in the correct flow. The Feedforward control system always depends on the forecasts results. The feedforward control system is required to find the irregularities and certain action should be taken in advance of actual results. The Feedforward control system requires measuring all the irregularities or disturbances that are present in the system. The changes in the process parameter should be change very carefully because it is very sensitive process in the Feedforward control system. The quality of the feedforward control system always depends on the accuracy of the outputs or accuracy of the process model.

Advantages of Feedback Control System

• There are many advantages in using the Feedback control system for process designing for a company or a business.
•  Feedback control system is very fast and the corrective actions are taken as soon as the control variable deviates from the plan.
• The corrective actions in the Feedback control system does not depends on the source and type of the disturbances present in the process.
• The Feedback control system does not require the full knowledge about the process and the outputs generated by it will be very accurate.

Advantages of Feedforward Control System

• The Feedforward control system is not an expensive system.
• The Feedforward does not take much time in the implementation.
• The Feedforward control system consumes very less power from the system.
• The Feedforward control system does not require high maintenance and it is easy to handle.

Disadvantages of Feedback Control System

• We do not get any predictive control actions in the Feedback control system.
• The Feedback control system is very sensitive for some processes like modeling errors and parameter changes that are related to the process.
• In Feedback control system the controlled variable cannot be measured in some situations.
• The feasibility of the Feedback control system is very low

Disadvantages of Feedforward Control System

• In Feedforward control system disturbance variables should be measured online and it is not feasible for many of the applications.
• The Feedback control system does not provide perfect control on the procedure.