robotics sensors

7/25/2019 Robotics Sensors

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SensorsSensors

VelocitySensors

TorqueSensor

Acceleration

Sensors

Position

Sensors

Force & Pressure

Sensor


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IntroductionIntroduction

Used forUsed for Internal FeedbackInternal Feedback

External InteractionExternal Interaction Some sensors possess similar inSome sensors possess similar in

function to that of the human andfunction to that of the human and

animal sensoranimal sensor


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Sensor CharacteristicsSensor Characteristics

CostCost

SizeSize

WeightWeight

Output !pesOutput !pes

InterfacingInterfacing"esolution"esolution

Sensiti#it!Sensiti#it!

$inearit!$inearit!

"ange"ange

"esponse time"esponse time

Fre%uenc!Fre%uenc!responseresponse

"eliabilit!"eliabilit!

&ccurac!&ccurac!

"epeatabilit!"epeatabilit!


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Position SensorsPosition Sensors

'otentiometer'otentiometer EncoderEncoder

IncrementalIncremental

&bsolute&bsolute $()$() "esol#ers"esol#ers $*) or *)$*) or *) +all,e-ect+all,e-ect

SensorSensor


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.'otentiometer/.'otentiometer/
http://www.answers.com/main/Record2?a=NR&url=http%3A%2F%2Fcommons.wikimedia.org%2Fwiki%2FImage%3AReochord.jpg


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.Encoder/.Encoder/


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'osition Sensors'osition Sensors

Absolute encoder

The optical disk of the absolute encoder is designed to produce a

digital word that distinguishes N distinct positions of the shaft. For

ea!ple" if there are # tracks" the encoder is capable of producing $%

distinct positions or an angular resolution of '.() *+),$%- degrees.

The !ost co!!on types of nu!erical encoding used in the absolute

encoder are gray and binary codes.


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'osition Sensors'osition Sensors

Incremental encoderIncremental encoder

Or a relative encoder, is simpler inOr a relative encoder, is simpler in

design than the absolute encoder. Itdesign than the absolute encoder. It

consists of two tracks and twoconsists of two tracks and two

sensors whose outputs are calledsensors whose outputs are called

channels A and B. As the shaftchannels A and B. As the shaft

rotates, pulse trains occur on theserotates, pulse trains occur on these

channels at a frequencychannels at a frequency

proportional to the shaft speed, andproportional to the shaft speed, and

the phase relationship between thethe phase relationship between the

signals yields the direction ofsignals yields the direction ofrotation. The code disk pattern androtation. The code disk pattern and

output signals A and B areoutput signals A and B are

illustrated in the igure.illustrated in the igure.
http://hades.mech.northwestern.edu/wiki/index.php/Image:Encoder_diagram.png


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(elocit! Sensors(elocit! Sensors EncoderEncoderechometersechometers )i-erentiation)i-erentiation

of 'ositionof 'osition


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&cceleration Sensors&cceleration Sensors

Based on piezoelectric technology various physicalBased on piezoelectric technology various physicaldimensions can be measured, the most importantdimensions can be measured, the most importantinclude pressure and acceleration. Figure showsinclude pressure and acceleration. Figure showsschematic configurations of those sensors in theschematic configurations of those sensors in thetransverse configuration. In both designs, thetransverse configuration. In both designs, theelements are thin cuboids that are loaded along theirelements are thin cuboids that are loaded along theirlongest extension. For pressure sensors, a thinlongest extension. For pressure sensors, a thinmembrane with known dimensions and a massivemembrane with known dimensions and a massivebase is used; assuring that an applied pressurebase is used; assuring that an applied pressure

specifically loads the elements in one direction. Forspecifically loads the elements in one direction. Foraccelerometers, a seismic mass is attached to theaccelerometers, a seismic mass is attached to thecrystal elements. hen the accelerometercrystal elements. hen the accelerometerexperiences a motion, the invariant seismic massexperiences a motion, the invariant seismic massloads the elements according to !ewton s second0loads the elements according to !ewton s second0

law of motion F"ma.law of motion F"ma.


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&cceleration Sensors&cceleration Sensors


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Force 1 'ressure SensorsForce 1 'ressure Sensors


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or%ue Sensorsor%ue Sensors

Miniature

Ranges 1 - 100 Nm

Keyed shaft

0-10 V or 4 - 20 mA

IP 50


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*iscellaneous Sensors*iscellaneous Sensors

*icro s2itch*icro s2itch

$ight and Infrared Sensors$ight and Infrared Sensorsouch and actile Sensorsouch and actile Sensors

'roximit! Sensors'roximit! Sensors

*agnetic3 Optical3 Ultrasonic3 Inducti#e3*agnetic3 Optical3 Ultrasonic3 Inducti#e3Capaciti#eCapaciti#e

"ange Finders"ange Finders

Sni- SensorsSni- Sensors

(ision Sensor(ision Sensor

(oice,"ecognition )e#ices(oice,"ecognition )e#ices

(oice S!nthesizers(oice S!nthesizers

"emote Center Com liance "CC )e#ice"emote Center Com liance ."CC/ )e#ice

robotics sensors

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