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Introduction
Engine and other automobile systems are increasingly controlled electronically. This has led to improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs. However the automobile is a hostile environment: especially in the engine compartment, where high temperature, humidity, vibration, electrical interference and a fine cocktail of potentially corrosive pollutants are present. These hostile factors may cause electrical contacts to deteriorate, surface resistances to fall and sensitive electronic systems to fail in a variety of modes. Some of these failure modes will be benign, whereas others may be dangerous and cause accidents and endanger to human life.
A cruise control system, or vehicle speed control system can keep a vehicle's speed constant on long runs and therefore may help prevent driver fatigue [2-5]. If the driver hands over speed control to a cruise control system, then the capability of the system to control speed to the set value is just as critical to safety as is the capability of the driver to control speed manually. So the cruise control system design is imperative and important to an automobile.
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Introduction
Engine and other automobile systems are increasingly controlled electronically. This has led to improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs. However the automobile is a hostile environment: especially in the engine compartment, where high temperature, humidity, vibration, electrical interference and a fine cocktail of potentially corrosive pollutants are present. These hostile factors may cause electrical contacts to deteriorate, surface resistances to fall and sensitive electronic systems to fail in a variety of modes. Some of these failure modes will be benign, whereas others may be dangerous and cause accidents and endanger to human life.
A cruise control system, or vehicle speed control system can keep a vehicle's speed constant on long runs and therefore may help prevent driver fatigue [2-5]. If the driver hands over speed control to a cruise control system, then the capability of the system to control speed to the set value is just as critical to safety as is the capability of the driver to control speed manually. So the cruise control system design is imperative and important to an automobile.
Summary
To keep an automobile’s speed constant, a speed control design method using fuzzy logic is
presented. PI fuzzy controller and PD fuzzy controller design schemes are given to regulate a vehicle’s speed to a driver-specified value. The simulation results show the validity and of the proposed technique.
The control design procedure can be summarized as follows:
① Modeling and performance objectives
Basically, the role of modeling a fuzzy control design is quite similar to its role in
conventional control system design. In fuzzy control there is a more significant emphasis on the use of heuristics. Conventional feedback controller design entails constructing a controller to meet the closed-loop specifications (such as disturbance rejection properties, insensitivity to plant parameter variations, stability, overshoot, steady-state error et al), which is also applied to fuzzy control design.
② Fuzzy controller design
Fuzzy control design essentially amounts to (1) choosing the fuzzy controller inputs and
outputs (2) choosing the preprocessing that is needed for the controller inputs and possibly postprocessing that is needed for the outputs, and (3) designing the four components of the fuzzy controller: (a) The fuzzification interface simply modifies the inputs so that they can be interpreted and compared to the rules in the rule-base. (b) The “rule-base” holds the knowledge, in the form of a set of rules, of how best to control the system. © The inference engine evaluates which control rules are relevant at the current time and then decides what the input to the plant should be. And (d) the defuzzification interface converts the conclusions reached by the inference engine into the inputs to the plant.
③ Computer simulation
To prove the effectivity of the controller design and check up whether the design requirements are realized or not.
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i need more information about the subject posted above
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please download the attached files for more details. if you are not satisfied, then contact us for further information.
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PRESENTED BY
CH.VASU BABU
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SPEED CONTROL DESIGN FOR A VEHICLE SYSTEM USING FUZZY LOGIC
Introduction
The idea behind fuzzy logic dates back to Plato, who recognized not only the logic system of true and false, but also an undetermined area – the uncertain.
In the 1960’s Lotfi A. Zadeh Ph.D,. University of California, Berkeley, published an obscure paper on fuzzy sets . His unconventional theory allowed for approximate information and uncertainty when generating complex solutions; a process that previously did not exist.
Fuzzy Logic has been around since the mid 60’s but was not readily excepted until the 80’s and 90’s. Although now prevalent throughout much of the world, China, Japan and Korea were the early adopters
Definition of fuzzy logic
Fuzzy logic provides a method to formalize reasoning when dealing with vague terms. Traditional computing requires finite precision which is not always possible in real world scenarios. Not every decision is either true or false, or as with Boolean logic either 0 or 1. Fuzzy logic allows for membership functions, or degrees of truthfulness and falsehoods. Or as with Boolean logic, not only 0 and 1 but all the numbers that fall in between.
• How is Fuzzy Logic Used?
Fuzzy Mathematics
Fuzzy Numbers – almost 5, or more than 50
Fuzzy Geometry – Almost Straight Lines
Fuzzy Algebra – Not quite a parabola
Fuzzy Calculus
Fuzzy Graphs – based on fuzzy points
Advantages
Disadvantages
Future scope
Advances in technology today are occurring at an amazing rate. The speed and complexity of application production would not be possible without systems like fuzzy logic. Lotfi A. Zadeh’s introduction of fuzzy logic generated the ability for companies, who choose to employ it, a competitive edge. They now have the ability to significantly reduce engineering development time in addition to producing extremely complex systems that would not be possible by employing previous methods.
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