Feedback improves system performance

Abstract

Every day we use feedback. For example, when we drive a car, we constantly adjust the steering or speed depending on what our senses are telling us about the current road situation. In this way, our eyes are acting as a measuring device and our brain as a controller and closing the loop from the car’s position or speed back to the steering or accelerating inputs. This feedback concept is also used in engineering systems; we often use electronic measurement and transducing equipment to feed back the information about how well the system is performing so that the controller can make an adjustment and correct for any errors. We have already looked at modelling the Actuator-Process-Transducer components of engineering systems; now, we look at how to extend our system knowledge and control engineering skills to create a transfer function representation of a closed-loop system and to understand what advantages a closed-loop system has over an open-loop system.