10/03/2023
What is a control system?✍️✍️✍️
A control system is a set of mechanical and/or electronic devices which regulate, manage, and command other devices or systems using control loops.
✅A control loop consists of all the physical components and control functions needed to adjust or maintain the value of a measured process variable (PV) to your desired value, or setpoint (SP). To do this, your loop needs at least three basic elements – an input, a controller, and an output.
👉There are two types of control loops: open and closed.
✅Open-loop system
As the simplest type of control loop, an open-loop system doesn’t measure variables or send output values to the controller.
✅Closed-loop system
Now that we know how an open-loop control system works, we’ll move on to the closed-loop system. The main difference between the two systems is feedback.
In the closed-loop system, you have a sensor to constantly monitor your output. This sensor feeds data back to the controller. With this data, the controller compares the output with your setpoint. If this comparison doesn’t match, the controller analyzes this error, using one of the control methods. Then it sends a signal to an actuator to change your process value and bring it closer to your setpoint.
If you drive, then you’ve used this system. Imagine you want to go from point A to point B as fast as the law allows. There is a 60 mile-per-hour speed limit on your route, so you want to maintain the speed of the car at 60.
Here, your eyes (the sensor) monitor the car’s velocity on the speedometer (the output). If you haven’t reached your setpoint, your brain (the controller) will tell you to press the gas pedal (the final control element) further down with your foot (the actuator). When you reach 60, you’ll set your foot in a position to maintain that speed.
It all works out great if you encounter no disturbances, such as a hill. If you go up a hill, your speed will decrease unless you change the position of your foot.
Yours
