A system is a combination of different components or devices that work to complement each other to perform a unique task assigned to the system. A system may have a controlled output or uncontrolled output. The systems having controlled output are control systems. This article will explain the open loop control system, its examples, advantages, disadvantages, and applications.
What is a Control System?
A control system consists of an input, a controller or processor, and an output. It works by giving an input signal to a controller. The controller then generates a control signal which generates output within specified limits. For example, while using an oven, you can set a timer for heating your food. The timer is a control signal that will turn off the oven after the set time limit. The kind of control system which we are going to discuss in this article is the Open Loop Control System.
An Open Loop Control System
An open loop control system, as the name indicates, has a controlled process through which it gives output. However, as it is an open-loop system, it does not have a feedback system. This means that output will have no effect on input, and it does not act as a control variable for the input. We can say that in an open-loop control system, the signal flows in one direction only.
Even if the desired output is not achieved due to any error or environmental conditions, the output cannot be regulated due to the absence of feedback in the open-loop control system.
Gain of Open Loop Control System
The gain of an open loop system is calculated to determine the performance of the system. As the gain is calculated by the ratio of output to input, it indicates to which extent output conforms to the input.
Let’s say the gain of the controller is G1(s) and the gain of the controlled process is G2(s) then the overall gain of the open loop system can be calculated as:
So, G(s) gives the gain of an open-loop control system.
Benefits of Open Loop Control System
Following are the benefits of open loop control system
- It is easy to design and use due to its simple construction.
- It is also economical due to its simple design.
- The Open Loop Control system brings about a stable result.
Drawbacks of Open Loop Control System
The drawbacks of open loop control system are mentioned below
- It is needed to be recalibrated timely to ensure accuracy
- It cannot be used for automation because there is no feedback system for correction of output.
- There is more probability of occurring error in an Open Loop Control System
Implementation of Open Loop Control System in Real Life
There are many open-loop control systems in our surroundings. These include washing machines, dryers, traffic signals, electric hand dryers, bread toasters, ovens, and TV remote controls.
For example, traffic signals have set times for each traffic light. Each traffic light automatically turns ON and OFF within specified time limits. However, traffic signals cannot change their timings according to the volume of traffic, which shows the absence of feedback in open-loop control systems.
You can think of how other examples mentioned above are open-loop control systems.
Conclusion
Open loop control systems are systems that have controlled output, but their output cannot vary the input signal through a feedback process. They are useful because they are simple and easy to maintain, but they cannot be used for automation.
