Tugino, ST MT [email protected] Jurusan Teknik Elektro...

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Tugino, ST [email protected]

Jurusan Teknik ElektroSTTNAS Yogyakarta

Sensor pada Robot Pemadam Api

Flame DetektorSpeed sensorUltra sonic sensorFlame NavigatorLDR sensorIR distance sensor

Tugino, ST MT STTNAS Yogyakarta 2

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Robot AB-Tech ( Juara 2 KRCI Reg 3)


SISTEM PENGENDALIAN

Sensor jarak kiri

Sensor jarak kanan

Sensor jarak depan MikrokontrollerAT89S51

Flame detektorLCD

Driver PWM

Driver

Motor kiri

Motor kanan

Motor kipas


Sensor jarak serong kanan

Sensor jarak serong kiri Sensor garis putih

Motor Servo

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sensor

Flame DetektorFlame NavigatorUltrasonic sensor


Sensor line tracker

Flame Detektor


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Ultrasonic sensor


White floor Detector


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Sensor pada Robot AIBO


Sensor pada Robot Shadow Biped


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Buku Acuan

Sensors for mobile robots: theory and applications, H. R. Everett, A. K. Peters Ltd, C1995, ISBN: 1-56881-048-2

Handbook of Modern Sensors: Physics, Designs and Applications, 2nd edition,Jacob Fraden AIP Press/Springer 1996


Jacob Fraden, AIP Press/Springer, 1996.ISBN 1-56396-538-0.

Websites acuan

http://www.omega.com/ (sensors + hand-helds)http://www.extech.com/ (hand-helds)http://www.agilent.com/ (instruments, enormous)http://www.keithley.com/ (instruments, big)http://www.tegam.com/ (instruments, small)http://www.edsci.com/ (optics ++)


p // / ( p )http://www.pacific.net/~brooke/Sensors.html(comprehensive listing of sensors etc. and links)

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Apa itu sensor ?Sensor – adalah peralatan electrical/mechanical/chemical yang / / y gmemetakan suatu keadaan ke dalam betuk besaran pengukuran Masing-masing sensor didasarkan pada prinsip perpindahan - mengkonversi dari energi satu ke energi yang lain


Sensor yang dimiliki manusia

Penglihatan : mata (optics, light)g ( p , g )Pendengaran : Telinga (acoustics, sound)Sentuhan : Kulit (mechanics, heat)Bau : Hidung (vapor-phase chemistry)


chemistry)Rasa : Lidah (liquid-phase chemistry)

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Tranduser Elektronik Thermistor: temperature-to-resistanceElectrochemical: chemistry-to-voltagePhotocurrent: light intensity-to-currentPyroelectric: thermal radiation-to-voltageHumidity: humidity-to-capacitanceLength (LVDT: Linear variable differential transformers) : position-to-inductance


Microphone: sound pressure-to-<anything>

Klasifikasi Sensor Proprioception (Internal ) v.s. Exteroceptive (external )

M k il i i t i t l b t t h Mengukur nilai sistem internal robot contoh level battery , posisi roda , sudut sendi , dll,Mendeteksikondisi lingkungan/objek

Aktif v.s. Pasif Memancarkan energi contoh radar, sonarMenerima energi contoh camera


Kontak v.s. non-kontak Visual v.s. non-visual

vision-based sensing, image processing, video camera

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Proprioceptive SensorsEncoders, Potentiometers

Mengukur sudut dengan mengetahui Mengukur sudut dengan mengetahui perubahan resisten atau pencacah optik

GyroscopesMengukur rata2 perubahan sudut fiber-optic (saat ini ), magnetic (dulu )

Compass


CompassMengukur posisi

GPS: Mengukur lokasi di bumi

Electromagnetic SpectrumElectromagnetic SpectrumVisible Spectrum

700 nm 400 nm


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Sensors Based on EM Spectrum

Radio and MicrowaveRadio and MicrowaveRADAR: Radio Detection and RangingMicrowave radar: insensitive to clouds

Coherent lightall photons have same phase and wavelengthLASER: Light Amplification by Stimulated


LASER: Light Amplification by Stimulated Emission of RadiationLASER RADAR: LADAR - accurate ranging

Sensors Based on EM SpectrumLight sensitive

eyes, cameras, photocells etc.Operating principleOperating principle

CCD - charge coupled devicesphotoelectric effect

IR sensitive Local Proximity Sensing

Infrared LEDs (cheap, active sensing)s all lo esol tion no mall sed fo


usually low resolution - normally used for presence/absence of obstacles rather than ranging, operate over small range

Sense heat differences and construct imagesHuman detection sensorsnight vision application

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General Classification (1)


General Classification (2)


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Sensors Used in Robot

Pyroelectric Detector

Gas Sensor

Gieger-MullerRadiation Sensor

Piezo Bend SensorPendulum Resistive

Tilt Sensors

GyroAccelerometer

Metal Detector

Digital Infrared Ranging

Touch Switch

Pressure Switch

Limit Switch

Magnetic Sensor

Miniature Polaroid Sensor

Thyristor

Resistive Bend Sensors

Mechanical Tilt Sensors

CDS Cell Resistive Light Sensor

IR Sensor w/lensIR Pin Diode

UV Detector

Tugino, ST MT STTNAS Yogyakarta 24Solar Cell

Compass

Magnetic Reed Switch

Magnetic Sensor

Polaroid Sensor Board

Piezo Ultrasonic Transducers

Hall EffectMagnetic Field

Sensors

Compass

IRDA Transceiver

IR Amplifier Sensor

IR ModulatorReceiverLite-On IR

Remote ReceiverRadio Shack

Remote Receiver

IR ReflectionSensor

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Sensors Used in RobotResistive sensors

Sensors lekukan, potentiometer, resistive photocells, ...Tactile sensorsTactile sensors

contact switch, bumpers…Infrared sensors

Reflective, proximity, distance sensors…Ultrasonic Distance SensorInertial Sensors (measure the second derivatives of position)


Accelerometer, Gyroscopes, Orientation Sensors

Compass, InclinometerLaser range sensorsVision, GPS, …

Resistive Sensors

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Bend Sensors• Resistance = 10k to 35k• As the strip is bent, resistance increases

Resistive Sensors

Resistive Bend Sensor

Potentiometers• Can be used as position sensors for sliding mechanisms or rotating shafts • Easy to find, easy to mount Potentiometer


Light Sensor (Photocell)• Good for detecting direction/presence of light • Non-linear resistance• Slow response to light changes Photocell

R is small when brightly illuminated

Aplikasi Resistive Bend Sensor


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ApplicationsSensor

Measure bend of a jointMeasure bend of a joint

Wall Following/Collision Detection

Sensors


Weight SensorSensor

Inputs for Resistive SensorsVoltage divider:

You have two resisters, oneis fixed and the other varies

V

R1

R2

Vsense

is fixed and the other varies,as well as a constant voltage

micro

V

VRR

RVsense21

2

+=

A/D converter

Di i l I/O


Comparator: If voltage at + is greater than at -, digital high out

+-

Binary Threshold

Digital I/O

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Infrared SensorsIntensity based infrared

Reflective sensors Easy to implementEasy to implementsusceptible to ambient light

Modulated InfraredProximity sensorsRequires modulated IR signalInsensitive to ambient light

Infrared Ranging


Distance sensorsShort range distance measurementImpervious to ambient light, color and reflectivity of object

Intensity Based Infrared

Break-Beam sensor

volta

ge

Increase in ambient light raises DC bias

Reflective Sensor


• Easy to implement (few components)• Works very well in controlled environments• Sensitive to ambient light

time

volta

ge

time

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IR Reflective SensorsReflective Sensor:

Emitter IR LED + detector photodiode/phototransistorPhototransistor: the more light reaching the phototransistor, the more current passes through itA beam of light is reflected off a surface and into a detectorLight usually in infrared spectrum, IR light is invisible

Applications:Object detection, Line following, Wall trackingOptical encoder (Break-Beam sensor)


Drawbacks:Susceptible to ambient lighting

Provide sheath to insulate the device from outside lighting Susceptible to reflectivity of objectsSusceptible to the distance between sensor and the object

DETEKTOR GARIS PUTIH

Untuk pengaktifan pada start awal

TONE DETEKTOR


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White floor Detector


Modulated Infrared

Modulation and DemodulationFlashing a light source at a particular frequencyDemodulator is tuned to the specific frequency of light flashes (32kHz 45kHz)flashes. (32kHz~45kHz)Flashes of light can be detected even if they are very week Less susceptible to ambient lighting and reflectivity of objectsUsed in most IR remote control units, proximity sensors


Negative true logic:

Detect = 0v

No detect = 5v

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IR Proximity Sensorslimiter demodulator

bandpass filteramplifiercomparator

integrator

Proximity Sensors: Requires a modulated IR LED, a detector module with built-in modulation decoderCurrent through the IR LED should be limited: adding a series resistor in LED driver circuitDetection range: varies with different objects (shiny white card vs. dull black object)Insensitive to ambient light


Applications:Rough distance measurement Obstacle avoidanceWall following, line following

IR Distance SensorsBasic principle of operation:

IR emitter + focusing lens + position-sensitive detector

Modulated IR light


Location of the spot on the detector corresponds to the distance to the target surface, Optics to covert horizontal distance to vertical distance

Modulated IR light

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IR Distance SensorsSharp GP2D02 IR Ranger

Distance range: 10cm (4") ~ 80cm (30").Moderately reliable for distance measurement ode a e y e ab e o d s a ce easu e eImmune to ambient light Impervious to color and reflectivity of objectApplications: distance measurement, wall following, …


IR Distance Detector Sharp GP2D12


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SENSOR INFRA REDSensor jarak menggunakan sensor INFRA RED

Diagram blok detektor dinding

FLAME NAVIGATOR

Basic Navigation Techniques

• Relative Positioning (called Dead-reckoning)– Information required: incremental (internal)

Velocityheadingheading

– With this technique the position can be updated with respect to a starting point– Problems: unbounded accumulation error

• Absolute Positioning – Information Required: absolute (external)– Absolute references (wall, corner, landmark)– Methods


Magnetic Compasses (absolute heading, earth’s magnetic field)Active BeaconsGlobal Positioning Systems (GPS)Landmark Navigation (absolute references: wall, corner, artificial landmark)Map-based positioning

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Dead ReckoningCause of unbounded accumulation error:

Systematic Errors:) U l h l di ta) Unequal wheel diameters

b) Average of both wheel diameters differs from nominal diameter

c) Misalignment of wheelsd) Limited encoder resolution,

sampling rate, …Nonsystematic Errors:a) Travel over uneven floors


a) Travel over uneven floorsb) Travel over unexpected objects on

the floorc) Wheel-slippage due to : slippery

floors; over-acceleration, fast turning (skidding), non-point wheel contact with the floor

Sensors used in navigationDead Reckoning

Odometry (monitoring the

External SensorsCompassOdometry (monitoring the

wheel revolution to compute the offset from a known starting position)

Encoders,Potentiometer,Tachometer, …

– Inertial Sensors ( th d d i ti

pUltrasonicLaser range sensorsRadarVisionGlobal Positioning System (GPS)


(measure the second derivative of position)

Gyroscopes,Accelerometer, …

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Motor Encoder

• Relative position - calibration ?

- direction ?

l ti ?light sensor

Incremental Optical Encoders

- resolution ?

grating

light emitter

g

decode circuitry


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Velocity Detector


Incremental position encoderpuses a single line that alternates black/white

two slightly offset sensors produce outputs as shown belowdetects motion in either direction, pulses are counted to determine absolute


a e cou ted to dete e abso uteposition (which must be initially reset)

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counting techniques


Opto-switch sensorInductive sensor

Sensor Kecepatan Motor

Tampak Samping

Tampak Depan

Bentuk Gelombang

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DETEKTOR PUTARAN RODA

Detektor putaran roda Detektor putaran roda menggunakan roda pencacah dan menggunakan roda pencacah dan rangkaian rangkaian optoopto--couplercouplerPancaran sinar infra merah yang Pancaran sinar infra merah yang diterima oleh fototransistor, jika diterima oleh fototransistor, jika terhalang maka output bernilai terhalang maka output bernilai tegangan 5 Volt ( logika 1 ), dan tegangan 5 Volt ( logika 1 ), dan sebaliknya jika tidak terhalang sebaliknya jika tidak terhalang m k tp t k l r n t g ng n 0 m k tp t k l r n t g ng n 0


maka output keluaran tegangan 0 maka output keluaran tegangan 0 Volt ( logika 0Volt ( logika 0 ).

Quiz 1:

If there are 100 lines in the grating, what is the smallest


detectable change in motor-shaft angle?


Quiz 2:

How could you augment a grating-based (relative) encoder in order to detect the direction of rotation?

light emitter/detector

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• Relative position light sensor

- calibration ?

- direction ?

l ti ?


grating

light emitter

g

decode circuitry

A

- resolution ?

Tugino, ST MT STTNAS Yogyakarta 53B

A

B

A leads B


- directionlight sensor

• Incremental Encoder:

- resolution

grating

light emitter

decode circuitry

A

• It generates pulses proportional to the rotation speed of the shaft.• Direction can also be indicated with a two phase encoder:


B A leads B

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Incremental Optical EncodersA

• Incremental Encoder:

B A leads B

ChA


ChB

DIR

Encoder pulse and motor direction

Absolute position encoderssensor is an array of photodiodes

Incremental position encoder


p

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Absolute Optical Encoders• Used when loss of reference is not possible.• Gray codes: only one bit changes at a time ( less uncertainty).• The information is transferred in parallel form (many wires are necessary).

Gray Code

000

001

011

010

000

001

010

011

Binary


110

111

101

100

100

101

110

111

Other Odometry Sensors• Resolver

It has two stator windings positioned g pat 90 degrees. The output voltage is proportional to the sine or cosine function of the rotor's angle. The rotor is made up of a third winding, winding C


• Potentiometer

= varying resistance

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Flame Detektor


Range FinderTime of FlightThe measured pulses typically come p yp yform ultrasonic, RF and optical energy sources.

D = v * tD = round-trip distancev = speed of wave propagation


t = elapsed time

Sound = 0.3 meters/msecRF/light = 0.3 meters / ns (Very difficult to measure short distances 1-100 meters)

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Ultrasonic SensorsBasic principle of operation:Emit a quick burst of ultrasound (50kHz), (human hearing: 20Hz to 20kHz) M th l d ti til th i i di t Measure the elapsed time until the receiver indicates that an echo is detected.Determine how far away the nearest object is from the sensor

D = v * tD = round-trip distancev = speed of propagation(340 m/s)


v = speed of propagation(340 m/s)t = elapsed time

Bat, dolphin, …

Sensor Ultra SonicTransmiter 40 kHz

Reciever


Reciever

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Sensor Ultra SonicTransmiter 40 kHz

Reciever


Reciever

Ultrasonic sensor


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Ultrasonic Sensors

Ranging is accurate but bearing has a 30 degree


g g g guncertainty. The object can be located anywhere in the arc.Typical ranges are of the order of several centimeters to 30 meters.Another problem is the propagation time. The ultrasonic signal will take 200 msec to travel 60 meters. ( 30 meters roundtrip @ 340 m/s )

Tone Detector

Untuk pengaktifan pada saat starUntuk pengaktifan pada saat star


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Polaroid Ultrasonic Sensors–It was developed for an automatic camera focusing system

Range: 6 inches to 35 feet

Ultrasonic transducer

Electronic boardTransducer Ringing:transmitter + receiver @ 50 KHzResidual vibrations or ringing may be interpreted as the echo i l

–Range: 6 inches to 35 feet


signalBlanking signal to block any return signals for the first 2.38ms after transmission

http://www.acroname.com/robotics/info/articles/sonar/sonar.html

Operation with Polaroid UltrasonicThe Electronic board supplied has the following I/0

INIT : trigger the sensor, ( 16 pulses are transmitted )BLANKING : goes high to avoid detection of own signalECHO : echo was detected.ECHO : echo was detected.BINH : goes high to end the blanking (reduce blanking time < 2.38 ms) BLNK : to be generated if multiple echo is required

t


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Ultrasonic SensorsApplications:

Distance MeasurementMapping: Rotating proximity scans (maps the app g o a g p o y sca s ( aps eproximity of objects surrounding the robot)


Scanning at an angle of 15º apart can achieve best results

Noise Issues


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Global Positioning System (GPS)24 satellites (+several spares)

b d i id i bi l

Space Segment

broadcast time, identity, orbital parameters (latitude, longitude, altitude)


http://www.cnde.iastate.edu/staff/swormley/gps/gps.html

Thank you!


Tugino, ST MT [email protected] Jurusan Teknik Elektro...

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