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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)
Tugino, ST MT STTNAS Yogyakarta 3
SISTEM PENGENDALIAN
Sensor jarak kiri
Sensor jarak kanan
Sensor jarak depan MikrokontrollerAT89S51
Flame detektorLCD
Driver PWM
Driver
Motor kiri
Motor kanan
Motor kipas
Tugino, ST MT STTNAS Yogyakarta 4
Sensor jarak serong kanan
Sensor jarak serong kiri Sensor garis putih
Motor Servo
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sensor
Flame DetektorFlame NavigatorUltrasonic sensor
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Sensor line tracker
Flame Detektor
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Ultrasonic sensor
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White floor Detector
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Sensor pada Robot AIBO
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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
Tugino, ST MT STTNAS Yogyakarta 11
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 ++)
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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
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Sensor yang dimiliki manusia
Penglihatan : mata (optics, light)g ( p , g )Pendengaran : Telinga (acoustics, sound)Sentuhan : Kulit (mechanics, heat)Bau : Hidung (vapor-phase chemistry)
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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
Tugino, ST MT STTNAS Yogyakarta 15
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
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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
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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
Tugino, ST MT STTNAS Yogyakarta 19
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
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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)
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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)
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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
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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
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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
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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
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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
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• 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)
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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
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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
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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
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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
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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, …
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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
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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
Tugino, ST MT STTNAS Yogyakarta 43
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)
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(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
Tugino, ST MT STTNAS Yogyakarta 46
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Velocity Detector
Tugino, ST MT STTNAS Yogyakarta 47
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
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a e cou ted to dete e abso uteposition (which must be initially reset)
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counting techniques
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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
Tugino, ST MT STTNAS Yogyakarta 51
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
Incremental Optical Encoders
detectable change in motor-shaft angle?
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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 ?
Incremental Optical Encoders
grating
light emitter
g
decode circuitry
A
- resolution ?
Tugino, ST MT STTNAS Yogyakarta 53B
A
B
A leads B
Incremental Optical Encoders
- 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:
Tugino, ST MT STTNAS Yogyakarta 54
B A leads B
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Incremental Optical EncodersA
• Incremental Encoder:
B A leads B
ChA
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ChB
DIR
Encoder pulse and motor direction
Absolute position encoderssensor is an array of photodiodes
Incremental position encoder
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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
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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
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• Potentiometer
= varying resistance
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Flame Detektor
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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
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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)
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v = speed of propagation(340 m/s)t = elapsed time
Bat, dolphin, …
Sensor Ultra SonicTransmiter 40 kHz
Reciever
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Reciever
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Sensor Ultra SonicTransmiter 40 kHz
Reciever
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Reciever
Ultrasonic sensor
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Ultrasonic Sensors
Ranging is accurate but bearing has a 30 degree
Tugino, ST MT STTNAS Yogyakarta 65
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
Tugino, ST MT STTNAS Yogyakarta 66
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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
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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
Tugino, ST MT STTNAS Yogyakarta 68
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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)
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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)
Tugino, ST MT STTNAS Yogyakarta 71
http://www.cnde.iastate.edu/staff/swormley/gps/gps.html
Thank you!
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