Control Systems in our Daily Life

Everything in our universe needs some control. If you keep eating even after your stomach is full, then it leads to indigestion. There is also a time limit for performing certain tasks. You cannot keep during the same task throughout the day. Then you will have no time for other tasks in a day. So, not only engineering machines, but even human beings follow certain controls for their system.

A control system is defined as a set of devices that monitor or control the performance of another device. Control systems are both open loop and closed loop control system. In an open loop control system the output depends on the input. In a closed loop control system a feedback from the output is fed to the input and modifies the input. So, control systems effectively have an input, an output, a sensor or feedback mechanism, and a controller to modify the input based on feedback.

Say you are having soup in a restaurant. You taste the soup. You feel that the salt is not sufficient. The sensor used by your body to check the taste of the soup is taste buds on your tongue. You then add salt to the soup and again check the taste. If you feel the salt is not sufficient, you add salt again and then start having your soup. Here the input is the soup, the output is the correct taste of the soup, and the feedback is the salt taste.

Suppose you are filling up water in your water tank using a motor. You do not want the water to overflow. So, you install a water sensor at a certain height in the water tank. Once water reaches the level of the water sensor, a signal is sent to the motor and the motor automatically switches off. This type of control system is very important in saving water. In the NCEES FE Exam for electrical engineers, control systems will be covered.

Our eyes automatically close when the amount of light that falls on it increases. This is because our retina can only take a certain amount of light inside. All parts of our body, similar to our eyes have an inbuilt control mechanism.

Similarly, say you are mixing hot water and cold water in your bathtub. Your skin is the sensor that will tell you if the water temperature suits you. If the water gets too hot, then you have to reduce the flow of the hot water pipe. If the water gets cold, then you have to reduce the flow of the cold water pipe. So, there is a set point for the water temperature that you are trying to reach. All control systems will operate towards that set point or optimum value. Control system is an important subject for electrical engineers. Engineers taking the NCEES Exam must have a basic knowledge of control systems.

Even the human emotions run on a control system format. If someone is speaking bad about us or harming us, we try to speak politely and explain. If the person is on the opposite side keeps raising their voice, then after sometime we also raise our voice. But we make sure that we don’t reach a point where we land up beating each other. In this conversation, the other persons’ emotion and experience is an output that modifies or attracts our response. In the NCEES PE Exam, electrical engineers have a subject called control systems.