Sensors (v.1c)1 CENG4480_A1 Sensors Sensing the real world.

transcript

Sensors (v.1c) 1

CENG4480_A1Sensors

Sensing the real world

Sensors (v.1c) 2

Sensors

Motion (Orientation/inclination )sensorsForce/pressure/strainPositionTemperature and humidityRotary positionLight and magnetic field sensors

Sensors (v.1c) 3

Motion (Orientation/inclination sensors

Acceleration GyroscopeCompassTilt Sensor

Sensors (v.1c) 4

Accelerometerhttp://en.wikipedia.org/wiki/Accelerometer

Functions: measure acceleration in one or more directions,

position can be deduced by integration. Orientation sensing : tilt sensor Vibration sensing

Methods: Mass spring method ADXL78 (from Analog Device )

Air pocket method (MX2125)

Sensors (v.1c) 5

ADXL78 (from Analog Device http://www.analog.com/UploadedFiles/Data_Sheets/ADXL78.pdf )Mass spring type (output acceleration in G)Measure the capacitance to create output

Sensors (v.1c) 6

ADXL330 accelerometer for three (X,Y,Z ) directions http://www.analog.com/UploadedFiles/Data_Sheets/ADXL330.pdf

Sensors (v.1c) 7

2D translational accelerometerMX2125 (from www.parallax.com)

Gas pocket typeWhen the sensor

moves, the temperatures of the 4 sensors are used to evaluate the 2D accelerations

Sensors (v.1c) 8

Accelerometer demo:orientation sensing

http://www.youtube.com/watch?v=9NEiBDBXFEQhttp://www.youtube.com/watch?v=VP4-wdMMLFo

Self-balance RobotSensor demo

Sensors (v.1c) 9

Accelerometer demo :Tilt sensing demo

http://www.youtube.com/watch?v=C6uVrYz-j70

Tilt sensing demo

Sensors (v.1c) 10

Gyroscopes http://en.wikipedia.org/wiki/Gyroscope

Gyroscope Measure rotational angle

Rate Gyroscope measure the rate of rotation along 3-axes of X

(pitch), Y (roll), and Z (yaw). Modern implementations are using

Microelectromechanical systems (MEMS) technologies.

Gyroscope

Sensors (v.1c) 11

FEATURES Complete rate gyroscope on a single chip Microelectromechanical systems (MEMS) Z-axis (yaw-rate) response

APPLICATIONS GPS navigation systems Image stabilization Inertial measurement units Platform stabilization

Gyroscope to measure Rational acceleration ADXRS401 http://www.analog.com/UploadedFiles/Data_Sheets/ADXRS401.pdf

Sensors (v.1c) 12

Compass-- the Philips KMZ51 magnetic field sensor

50/60Hz (high) operation, a jitter of around 1.5°

Sensors (v.1c) 13

Rate gyroscope demo

http://www.youtube.com/watch?v=VP4-wdMMLFo

Using Gyroscope compass for virtual reality application in an iphone

Sensors (v.1c) 14

Application of motion sensorsSelf balancing robot

by Kelvin Ko http://hk.youtube.com/watch?v=2u-EO2FDFG0

35cm35cm

Motion sensors: gyroscope and accelerometer

Sensors (v.1c) 15

Complementary filterComplementary filter

Since Since

Combine two sensors to find outputCombine two sensors to find output

Sensors (v.1c) 16

Complementary filterComplementary filterθθ=rotation angle, =rotation angle, =filter time constant, s=laplace =filter time constant, s=laplace operator operator http://en.wikipedia.org/wiki/Low-pass_filterhttp://en.wikipedia.org/wiki/High-pass_filterhttp://en.wikipedia.org/wiki/High-pass_filter

Sensors (v.1c) 17

Self Balanced robot using Self Balanced robot using complementary filtercomplementary filter

Sensors (v.1c) 18

Tilt Sensor by OMRONhttp://rocky.digikey.com/WebLib/Omron%20Web%20Data/D6B.pdf

Detect tilting 35 ~ 65 degrees in right-and-left inclination

Sensors (v.1c) 19

Force/pressure/strain

Force-sensitive resistor (FSR)Strain gaugeFlexionAir pressure

Sensors (v.1c) 20

Force Sensing Resistorshttp://www.interlinkelectronics.com/library/media/papers/pdf/fsrguide.pdf

FSR402

Sensors (v.1c) 21

Force Sensing Resistor Demo

http://www.youtube.com/watch?v=LQ21lXr6egs

Sensors (v.1c) 22

Application for a walking robot

Walking robot

Sensors (v.1c) 23

Application of force sensing resistance sensors to balance a walking robot

Balancing Floor tilled rightupper leg bend left

Floor tilled leftupper leg bend rightNeutral position

Four sensors under the foot

Sensors (v.1c) 24

Four Force sensors under the foot

Sensors (v.1c) 25

The Nao robot uses force feedback at its feet

http://en.wikipedia.org/wiki/Nao_(robot)

http://www.robotshop.com/Images/xbig/fr/robot-humanoide-nao-edition-academique-v3plus-aldebaran.jpg

http://www.youtube.com/watch?v=2STTNYNF4lk

Sensors (v.1c) 26

Strain Gauge : Force sensorshttp://www.meas-spec.com/myMeas/default/index.asp

Piezoelectric crystal: produces a voltage that is proportional to force applied

Strain gauge: cemented on a rod. One end of the rod is fixed, force is applied to the other end. The resistance of the gauge will change with the force.

Sensors (v.1c) 27

Single element strain gauge

sensitive to temperature change.

resistance gauge unstrainedR

gauge theof length Lfactor, gauge strainG and G for

4424220

RVV bb

Gauge=R+Rgauge

Sensors (v.1c) 28

Four-element (Wheatstone bridge) strain gauge sensor,

Four times more sensitive than single gauge system; not sensitive to temperature change.

All gauges have unstrained resistance R.

RRVV bbb 2

b1=R-Rt2=R+ R

b2=R-R t1=R+RVb

Sensors (v.1c) 29

Flexion (bend) sensors

resistance: 10 KΩ (0°); 30-40 KΩ (90°) http://www.flexpoint.com/

http://www.jameco.com/wcsstore/Jameco/Products/ProdDS/150551.PDF

Sensors (v.1c) 30

Felixon resistance Demo

http://www.youtube.com/watch?v=m4E5SP7HCnk&feature=related

Sensors (v.1c) 31

Air pressure sensor

Measure up to 150 psi (pressure per square inch ).

Sensors (v.1c) 32

Position sensors

Infra-red range sensorLinear and Rotary position sensors

Sensors (v.1c) 33

Infra-red Range detectors by SHARP (4 to 30cm) http://www.acroname.com/robotics/info/articles/sharp/sharp.html

An emitter sends out light pulses. A small linear CCD array receives reflected light.

The distance corresponds to the triangle formed.

Sensors (v.1c) 34

IR radar using the Sharp range detector

http://www.youtube.com/watch?v=tStBLAiQaC8&feature=related

Sensors (v.1c) 35

Position sensors, from[1]

Rotary Linear

Optical shaft encoder

Sensors (v.1c) 36

Magnetic rotary encoder(http://www.renishaw.com/UserFiles/acrobat/UKEnglish/L-9517-9147.pdf)

non touch sensing

Sensors (v.1c) 37

Optical rotary encoder(http://en.wikipedia.org/wiki/Rotary_encoder)

The light received (on or off) will tell the rotation angle)

3 light emitters

3 light receivers

Rotation shaft

Light paths

http://www.youtube.com/watch?v=RuIislTGOwA

Crank shaft sensor

Sensors (v.1c) 38

Temperature and humidity

Temperaturehumidity

Sensors (v.1c) 39

Temperature sensorsLM135/235/335 features(from NS)http://www.national.com/pf/LM/LM135.html

Directly calibrated in °Kelvin 1°C initial accuracy available Operates from 400 µA to 5 mA Less than 1 Ohm dynamic impedance Easily calibrated Wide operating temperature range 200°C over range Low cost

Sensors (v.1c) 40

Application note (connecting to an ADC e.g. ADC0820 or ADC0801)

Sensors (v.1c) 41

Capacitive Atmospheric Humidity Sensorhttp://rocky.digikey.com/WebLib/BC%20Components/Web%20Data/2322%20691%2090001.pdf

BCcomponents 2322 691 90001 10-90%RH Dc

Sensors (v.1c) 42

Leaf Sensor Alerts When Plants Are Thirsty

http://www.youtube.com/watch?v=VM4X_fqPPco

Sensors (v.1c) 43

TSL250, TSL251, TSL252LIGHT-TO-VOLTAGE OPTICAL SENSORShttp://focus.ti.com/general/docs/scproducts.jsp

Light-to-voltage optical sensors, each combining a photodiode and an amplifier (feedback resistor = 16 MW, 8 MW, and 2 MW respectively).

The output voltage is directly proportional to the light intensity on the photodiode.

Sensors (v.1c) 44

Cadmium Sulfoselenide (CdS) Photoconductive Photocellshttp://faculty.uml.edu/aelbirt/16.480/pdvp5001.pdf

Light sensing using CdS

Sensors (v.1c) 45

Hall effect Sensors for sensing magnetic flux“B field”, see: http://doc.semicon.toshiba.co.jp/noseek/us/td/td2frame.htm

Sensors (v.1c) 46

Application on Magnetic levitation 磁懸浮http://myweb.msoe.edu/~muthuswamy/pubs/DesignOfMagneticLevitationControllersUsingJacobiLinearizationFeedbackLinearizationAndSlidingMode.pdf

http://www.youtube.com/watch?v=XjjBqzilkIc

Magnetic levitation Train Model 磁懸浮火車

http://www.youtube.com/watch?v=TeS_U9qFg7Y

frog levitationhttp://www.youtube.com/watch?v=A1vyB-O5i6E

Sensors (v.1c) 47

Hall effect sensors and brushless DC motors

Brushless DC motor

• http://dev.emcelettronica.com/files/u4/Brushless_DC_Motors_bldc_motor.jpg

Is it using Hall effect sensor? Don't known.

http://www.youtube.com/watch?v=JmRkxZT4XhYhttp://www.youtube.com/watch?v=cm0h2Qf3upQ

Sensors (v.1c) 48

Novel sensors

Kinect

http://www.youtube.com/watch?v=nvvQJxgykcU http://www.youtube.com/watch?v=Mf44bWQr3jc

http://www.ladyada.net/learn/diykinect/

Sensors (v.1c) 49

Many KINECT DIY projects

http://www.youtube.com/watch?v=Brpu30vjCa4&feature=related

http://www.youtube.com/watch?v=3V-TGXFZbbA&feature=related

Sensors (v.1c) 50

Control systemsExample: A temperature control

system

Sensors (v.1c) 51

Control example: Temperature control system

Temp.Sensor A/D

D/APulse Width modulation

& solid state relay

Heater

Sample&

Digital controlcircuit

Instrum. amp.

Water tank

computer

Sensors (v.1c) 52

Temperature control method 1: ON-Off (bang-bang) control (poor)

Easy to implement, bad control result -- contains overshoot undershot. Algorithm for on-off-control:

Loop forever: If (Tfrom_sensor > Treq required temperature)

then (heater off ) else (heater on).

Undershoot

Overshoot

TempOn-off control result

Steady state error

Sensors (v.1c) 53

Temperature control method 2 : Proportional-integral-differential (PID) temperature control (good)

Init. (set required temperature Treq)

Loop forever{ get temperature T from sensor, e=T - Treq

then Tw =e*G*{Kp+Kd*[d(e)/dt] +Ki*e dt } else

} //G,Kp,Kd,Ki can be adjusted by user

Proportional, differential, integral

Sensors (v.1c) 54

PID block diagram

http://www.controlviews.com/question12-12-03.html

Figure 1 - Parallel PID block diagram

Sensors (v.1c) 55

PID control using pulse width modulation PWM

Fixed period and fixed number of pulses

Tw (depends on e )

PID control resultof method 2

On-off control: oscillates and unstable

Temperature

Sensors (v.1c) 56

Summary

Studied the characteristics of various sensors

and their applications

Sensors (v.1c) 57

References

[1] S.E. Derenzo, Interfacing -- A laboratory approach using the microcomputer for instrumentation, data analysis and control prentice hall.

[2] D.A. Protopapas, Microcomputer hardware design, Prentice hall

[3] CUHK_FYP report HML0602, KHW0703

[4] http://www.engin.umich.edu/group/ctm [5] http://en.wikipedia.org/wiki/PID_controller

Sensors (v.1c)1 CENG4480_A1 Sensors Sensing the real world.

Documents