Introduction Introduction To To

MechatronicMechatronicss

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IntroductionIntroductionMechatronics is

synergistic (working together) integration of mechanical engineering, electronics and intelligent computer control in design and manufacture of products and processes

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Mechatronics System Mechatronics System ArchitectureArchitecture

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Mechatronics System ArchitectureMechatronics System Architecture

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two main

components

MechatronicsMechatronics

Mechatronics studies synergistic fusion of precise

mechatronical units, electronic, electro technical and computer components

for the purpose of designing and manufacturing qualitatively new

modules, systems, machines and complexes of machines

with intellectual control of their functional movements

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Sensors and TransducersSensors and TransducersSensor (e.g., thermometer)

◦a device that detects/measures a signal or stimulus

◦acquires information from the “real world”

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realworld

sensor

actuator

intelligentfeedbacksystem

Sensors CharacteristicsSensors CharacteristicsCharacteristics: To Select an appropriate

sensor one should consider the following characteristics◦Cost: Economical sensors should be used but it

should be balanced with other requirements such as reliability, accuracy, range, shape etc.

◦Size: Depending on the application of sensors. For examples thermocouples available in different lengths and sizes used according to the need

◦Weights: The weight of sensors are very important when used in dynamics machines

◦Type of out puts: it depends upon requirements of the user. e.g. potentiometer gives analog output and encoder gives digital outputs

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Sensors CharacteristicsSensors Characteristics◦Interfacing: The Sensor should be interface able

with other devices of systems and an important issue

◦Resolution: The minimum Step of size within the range of measurement of the sensor or minimum part of quantity measurable by sensor. Examples: in a wire wound potentiometer one turn

resistance is the resolution. And in digital n bits device is given by

Resolution=Fullrange/2n

◦Sensitivity: is the ratio of a change in output in response to a change in input. High sensitive sensors will show larger fluctuations in output as a result of fluctuations in input, including noise.

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Sensors CharacteristicsSensors CharacteristicsLinearity: The relation in input change to the

output change is constant is linearity. This means that in a sensor with liner output, the same change in input at any level within the range will produce the same change in output. Generally senors are linear to some extent. Non linearity can be made almost linear if non linearity function is known

Range: The difference b/n the smallest and largest outputs that a sensor can produced. The smallest and largest value of output for which sensor is considered accurate.

Response Time:The time required to give change in output by

sensors as result of sensed change input. It is expressed in percentages.

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Sensors CharacteristicsSensors CharacteristicsFrequency Response: The way that the system

output is related to the system input for different frequencies is called the frequency response of the system. The larger the range of the frequency response the better the ability of the system to respond to varying input. So it is important to know frequency response of the sensor.

Reliability: In general, reliability (systemic def.) is the ability of a person or system to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances.

Accuracy: The accuracy of a measurement system is the degree of closeness of measurements of a quantity to its actual (true) value.

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Sensors CharacteristicsSensors CharacteristicsRepeatability: is the variation in

measurements taken by a single person or instrument on the same item and under the same conditions. A measurement may be said to be repeatable when this variation is smaller than some agreed limit. Repeatability is more important than accuracy. Or the ability of the sensor to output the same value for the same input over a number of trials

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Position SensorsPosition SensorsA position sensor is any idea that permits

position measurement. It can either be an absolute position sensor or a relative one (displacement sensor). Position sensors can be either linear or angular. Position values could be used to calculate other derivatives.

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Position SensorsPosition SensorsPotentiometers: A potentiometer is an

instrument for measuring the potential (or voltage) in a circuit. The instrument taps off a fraction of a known voltage from a resistive slide wire and compares it with the unknown voltage by means of a galvanometer. The sliding contact or wiper of the potentiometer is adjusted and the galvanometer briefly connected to both the sliding contact and the unknown potential. The deflection of the galvanometer is observed and the sliding tap adjusted until the galvanometer no longer deflects from zero. At that point the galvanometer draws no current from the unknown source, and the magnitude of voltage can be calculated from the position of the sliding contact.

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Position SensorsPosition Sensors

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Potentiometer

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