Mani Raj Paul - Fuzzy Logic

The word fuzzy refers to things which are not clear or are vague. Any event, process, or function that is changing continuously cannot always be defined as either true or false, which means that we need to define such activities in a Fuzzy manner.

What is Fuzzy Logic?

Fuzzy Logic resembles the human decision-making methodology. It deals with vague and imprecise information. This is gross oversimplification of the real-world problems and based on degrees of truth rather than usual true/false or 1/0 like Boolean logic.
Take a look at the following diagram. It shows that in fuzzy systems, the values are indicated by a number in the range from 0 to 1. Here 1.0 represents absolute truth and 0.0 represents absolute falseness. The number which indicates the value in fuzzy systems is called the truth value

In other words, we can say that fuzzy logic is not logic that is fuzzy, but logic that is used to describe fuzziness. There can be numerous other examples like this with the help of which we can understand the concept of fuzzy logic

Advantages of Fuzzy Logic Control

Let us now discuss the advantages of Fuzzy Logic Control.
  • Cheaper − Developing a FLC is comparatively cheaper than developing model based or other controller in terms of performance.
  • Robust − FLCs are more robust than PID controllers because of their capability to cover a huge range of operating conditions.
  • Customizable − FLCs are customizable.
  • Emulate human deductive thinking − Basically FLC is designed to emulate human deductive thinking, the process people use to infer conclusion from what they know.
  • Reliability − FLC is more reliable than conventional control system.

Disadvantages of Fuzzy Logic Control

We will now discuss what are the disadvantages of Fuzzy Logic Control.
  • Requires lots of data − FLC needs lots of data to be applied.
  • Useful in case of moderate historical data− FLC is not useful for programs much smaller or larger than historical data.
  • Needs high human expertise − This is one drawback as the accuracy of the system depends on the knowledge and expertise of human beings.

Fuzzy Logic - Applications

In this chapter, we will discuss the fields where the concepts of Fuzzy Logic are extensively applied.

Aerospace

In aerospace, fuzzy logic is used in the following areas −
  • Altitude control of spacecraft
  • Satellite altitude control
  • Flow and mixture regulation in aircraft deicing vehicles

Automotive

In automotive, fuzzy logic is used in the following areas −
  • Trainable fuzzy systems for idle speed control
  • Shift scheduling method for automatic transmission
  • Intelligent highway systems
  • Traffic control
  • Improving efficiency of automatic transmissions

Business

In business, fuzzy logic is used in the following areas −
  • Decision-making support systems
  • Personnel evaluation in a large company

Defense

In defense, fuzzy logic is used in the following areas −
  • Underwater target recognition
  • Automatic target recognition of thermal infrared images
  • Naval decision support aids
  • Control of a hypervelocity interceptor
  • Fuzzy set modeling of NATO decision making

Electronics

In electronics, fuzzy logic is used in the following areas −
  • Control of automatic exposure in video cameras
  • Humidity in a clean room
  • Air conditioning systems
  • Washing machine timing
  • Microwave ovens
  • Vacuum cleaners

Finance

In the finance field, fuzzy logic is used in the following areas −
  • Banknote transfer control
  • Fund management
  • Stock market predictions

Industrial Sector

In industrial, fuzzy logic is used in following areas −
  • Cement kiln controls heat exchanger control
  • Activated sludge wastewater treatment process control
  • Water purification plant control
  • Quantitative pattern analysis for industrial quality assurance
  • Control of constraint satisfaction problems in structural design
  • Control of water purification plants

Manufacturing

In the manufacturing industry, fuzzy logic is used in following areas −
  • Optimization of cheese production
  • Optimization of milk production

Marine

In the marine field, fuzzy logic is used in the following areas −
  • Autopilot for ships
  • Optimal route selection
  • Control of autonomous underwater vehicles
  • Ship steering

Medical

In the medical field, fuzzy logic is used in the following areas −
  • Medical diagnostic support system
  • Control of arterial pressure during anesthesia
  • Multivariable control of anesthesia
  • Modeling of neuropathological findings in Alzheimer's patients
  • Radiology diagnoses
  • Fuzzy inference diagnosis of diabetes and prostate cancer

Securities

In securities, fuzzy logic is used in following areas −
  • Decision systems for securities trading
  • Various security appliances

Transportation

In transportation, fuzzy logic is used in the following areas −
  • Automatic underground train operation
  • Train schedule control
  • Railway acceleration
  • Braking and stopping

Pattern Recognition and Classification

In Pattern Recognition and Classification, fuzzy logic is used in the following areas −
  • Fuzzy logic based speech recognition
  • Fuzzy logic based
  • Handwriting recognition
  • Fuzzy logic based facial characteristic analysis
  • Command analysis
  • Fuzzy image search

Psychology

In Psychology, fuzzy logic is used in following areas −
  • Fuzzy logic based analysis of human behavior
  • Criminal investigation and prevention based on fuzzy logic reasoning

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