What is Control System? Definition, Types, and Examples

Control systems are used in a wide range of applications they are the essential parts of many modern devices and systems. In simple terms, Control systems are used to control the behavior of devices or any process.

In this article, we will be discussing the topic of Control Systems. We will cover the basics of what a Control System is, the different classifications of Control Systems, as well as the various types of Control Systems. We will also explain the difference between Open-loop and Closed-loop Systems. Finally, we will conclude our article by providing information on the Advantages and Disadvantages of Control Systems, their Applications, and some frequently asked questions.

What is a Control System?

A Control system is a system or a set of devices that manages command and directs the behavior of other devices or systems. It works on the principle of the input-process-output cycle. since the output is controlled by varying input. They are widely used in electronics, automation, and engineering.

It is made up of three components mainly: sensor, controller, and actuator. Here the sensor senses physical characteristics such as pressure, and temperature and converts them into an electrical signal and it generates an output signal which is used to control the actuator.

Block diagram of Control System

Examples of Control Systems

Control systems has various examples and it is widely used in day to day applications. Some examples are listed below:

• Elevators – In order to control or to regulate acceleration and braking mechanisms, Control systems are used.
• Smart Coffee Machine – For to control water temperature, coffee strength, and brewing rate control systems are used and all these properties are balanced to give desired flavor.
• Home Security and Automation – For to control and monitor wide aspects of home security such as cameras, sensors, motion detectors.
• Traffic light control systems – When an input processes through control system the output of three lights turned ON for some particular duration of time. Here input signal determines the output and It works based on timely basis.

Classification of Control Systems

Control system are classified as mentioned below by using suitable some parameters:

Control systems can be classified based on the type of signal we used and operate

• Continuous signal – Control signals are continuous with respect to time.
• Discrete signal – Consists of more discrete signals.

Control System can be classified on the Number of input and Output Present

• SISO – Single Input Single Output which consists of one input and one output.
• MIMO – Multiple Input Multiple Output which consists of two or more inputs to give outputs.

Control System can be classified based on the Feedback Path

• Open loop control system – Here control action is not dependent of desired output and it requires human efforts to operate.
• Closed loop control system – Here control action is dependent of output and input is applied to controller processes it to give signal.

Types of Control Systems

There are basically two types of control systems:

• Open-loop control system
• Closed-loop control system

Open-Loop Control System

In an open-loop controlled system a control signal which is considered input is sent to a system (Source), and the system responds without considering the output. The disadvantage of this system is it doesn’t continuously monitor the system’s behavior. The block diagram for this system is represented below.

Open Loop Control System

Examples of open-loop controlled system are:

• Washing machine – Here the operations of soaking, drying, rinsing done on a timely basis.
• Bread toaster and Microwave oven – These machine run on the basis of preset time period (specific time) irrespective of an output.
• Electric bulb – when an electric supply is available, by switching ON and OFF electric bulb works without the parameters such as temperature, intensity of the light.

Closed-Loop Control System

In an Closed-loop control system sensors used to provide system performance and then adjust the control input accordingly. This system is also called feedback control system. well comparing to OLCS it continuously monitor the output and make some changes based on the difference between desired output and actual output.

Closed Loop Control System

Examples of Closed-loop control system are:

• Thermostat heater – It maintains and control the temperature.
• Voltage stabilizer – It measures the fluctuations in voltage and reduces & maintains the voltage to a desired level.
• Human on any action – When any person looks for any consequences and changes the position based on it. It is also an example of closed-loop control system.
• It also contains home appliances such as AC, Refrigerator, and in industry appliances too.

Difference Between Open Loop and Closed Loop Control System

Here are some of the key differences between Open Loop and Closed Loop Control System:

Open Loop Control System	Closed Loop Control System
It is economical and inaccuracy.	It is expensive and accurate.
It does not have an feedback path.	It has an feedback path.
Control action is not dependent on output.	Control action is dependent on output.
It is designed easily.	It is hard to design.
It is called Non feedback control system	It is called Feedback control system.

Features of Control Systems

Some key features of Control Systems are:

• Control sources should be easily understandable and manageable for both clients and managers. If not then the complicated devices may not be properly functioned. So main thing is good control system design is needed for ease understandability.
• Control systems should provide organizational needs to give meaningful results.
• Control systems should be adequate and appropriate to achieve the objectives which can suitable used for the enterprises. (Objectives should be smart)
• It should be simple.
• Control systems use efficient control techniques to detect any sudden deviations which helps in achieving the desired results at earlier.
• Control systems should be flexible and forward looking towards future and so on.

Embedded Control Systems

We all aware of Embedded systems, It consists of combination of hardware and software support designed for specific purpose or an task is called Embedded system on the other hand a system which is embedded into a complex system to control the activities, track the status, and monitor the results with hardware and software functionalities is called Embedded control systems.

Examples : Patient monitoring in healthcare administration, To regulate and control vehicles speed in automobile industries and so on.

Applications such as Automotive industries, Defense systems, Medical devices and Industrial processes, etc.

Advantages and Disadvantages of Control Systems

There are some list of Advantages and Disadvantages of Control Systems given below :

Advantages of Control Systems

• Control systems having the capability to respond something faster than humans and control systems are very reliable.
• It can automate various tasks by reducing the human intervention which leads to increased productivity and decrease labor costs.
• Control systems are adaptable in any conditions and in any requirements and they can be reprogrammed to accommodate different operating functions.
• Many control systems are controlled and monitored remotely which is valuable in applications like space science and remote infrastructure.
• They are used to optimize complex processes and find the best operations to achieve the goal such as increased throughput.

Disadvantages of Control Systems

• Designing and implementation of control systems are more expensive.
• They need regular maintenance and updates for their functions in any operations.
• They highly depend on electricity which means they need continuous power supply and in case of power failure can disrupt any operation.
• They are very sensitive to environmental constraints such as light, temperature, and pressure.
• Control systems need high specialized knowledge which is complex to operate and handle.

Applications of Control Systems

Some Applications of Control System are:

• Medical Equipment – It is used to control various types of medical machines such as dialysis machine, X-ray machines.
• Farming and Agriculture – Control systems are used to automate and optimize various types of tasks in agricultural processes such as crop harvesting, fertilization etc.
• Robotics – Here the control systems mainly used to control and automate the movements of robots for any operations.
• Power and Energy Systems – It optimizes power generation, consumption and distribution improving the operational efficiency of power plants.
• Environmental Control – HVAC systems used to regulate physical or chemical characteristics.
• Transportation – Control systems control various aspects of transportation such as traffic control systems, air-traffic controller, etc.
• Industrial Automation – They optimize production processes in mills, factories, and other manufacturing industries.
• IoT and Home automation – IoT and home automation used to control and automate various systems in home or building such as air conditioning, heating, and security.

Conclusion

Well! Control systems as we today have various applications and uses. In industries Control systems are used for production support and machine functioning. we can use different types of control systems based on different purposes and individual needs to satisfy the requirements.

The scope of control systems has wide roots from home appliances to industries. In this article we have covered basics of control system and its types, pros and cons, features in detail.

Control System – FAQs

What is a control system in a circuit?

A control system in a circuit is a system that manages or regulates the behavior of other components within the circuit to achieve a desired output or performance.

What are the 4 parts of the control system?

The four main components of a control system are the sensor (or measurement device), controller, actuator (or final control element), and feedback loop.

What are example of control system in our daily life?

Some of the Examples of Control System in Daily Lifes are elevators, smart coffee machines, home security and automation systems, and traffic light control systems.

How are Control System Classified?

Control Systems are Classified based on Types of Signal Which is Continuous and Discrete Signal, Based on Number of Inputs and Outputs which are SISO and MIMO and they are also classified based on Feedback Path which is Open-loop and Closed-loop system.

What are the types of control in system?

Control systems are categorized into open-loop and closed-loop (feedback) control.