Ceng4480 a1

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Nao-NEX GEN...project...!!!!

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Ceng4480 a1

  1. 1. JANGAM RAKESHKUMARSNIGDHA ROYSANJAY KALKAREPRIYA ANAMIKANEHA Sensors (v.1c) 1
  2. 2. CENG4480_A1 SensorsSensing the real world Sensors (v.1c) 2
  3. 3. Sensors Motion (Orientation/inclination )sensors Force/pressure/strain Position Temperature and humidity Rotary position Light and magnetic field sensors Sensors (v.1c) 3
  4. 4. Motion (Orientation/inclinationsensors Acceleration Gyroscope Compass Tilt Sensor Sensors (v.1c) 4
  5. 5. 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
  6. 6. ADXL78 (from Analog Devicehttp://www.analog.com/UploadedFiles/Data_Sheets/ADXL) Mass spring type (output acceleration in G) Measure the capacitance to create output Sensors (v.1c) 6
  7. 7. ADXL330 accelerometer for three (X,Y,Z ) directionshttp://www.analog.com/UploadedFiles/Data_Sheets/ADXL330.pdf 3D Sensors (v.1c) 7
  8. 8. 2D translational accelerometerMX2125 Gas pocket type When the sensor moves, the temperatures of the 4 sensors are used to evaluate the 2D accelerations Sensors (v.1c) 8
  9. 9. Accelerometer demo:orientation sensing Self-balance Robot Sensor demo Sensors (v.1c) 9
  10. 10. Accelerometer demo :Tilt sensing demo Tilt sensing demo Sensors (v.1c) 10
  11. 11. Gyroscopes Gyroscope Measure rotational angle Rate Gyroscope 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. Sensors (v.1c) 11
  12. 12. Gyroscope to measure Rational acceleration ADXRS401FEATURES Complete rate gyroscope on a single chip Microelectromechanical systems (MEMS) Z-axis (yaw-rate) responseAPPLICATIONS GPS navigation systems Image stabilization Inertial measurement units Platform stabilization Sensors (v.1c) 12
  13. 13. Compass-- the Philips KMZ51magnetic field sensor 50/60Hz (high) operation, a jitter of around 1.5° Sensors (v.1c) 13
  14. 14. Rate gyroscope demoUsing Gyroscope compass for virtual reality application in an iphone Sensors (v.1c) 14
  15. 15. Application of motion sensorsSelf balancing robot by Kelvin Ko Motion sensors: http://hk.youtube.com/watch?v=2u-EO2FDFG0 gyroscope and accelerometer 20cm 35cm Sensors (v.1c)35cm 15
  16. 16. Complementary filter Since Combine two sensors to find output Sensors (v.1c) 16 16
  17. 17. Complementary filterθ=rotation angle, τ=filter time constant, s=laplaceoperatorhttp://en.wikipedia.org/wiki/Low-pass_filter Sensors (v.1c) 17 17
  18. 18. Self Balanced robot usingcomplementary filter Sensors (v.1c) 18 18
  19. 19. Tilt Sensor by OMRON Detect tilting 35 ~ 65 degrees in right-and- left inclination Sensors (v.1c) 19
  20. 20. Force/pressure/strain Force-sensitive resistor (FSR) Strain gauge Flexion Air pressure Sensors (v.1c) 20
  21. 21. Force Sensing Resistors FSR402 Sensors (v.1c) 21
  22. 22. Force Sensing Resistor Demo Sensors (v.1c) 22
  23. 23. Application for a walking robot Walking robot Sensors (v.1c) 23
  24. 24. Application of force sensing resistancesensors to balance a walking robot Balancing Floor tilled left Floor tilled rightNeutral position upper leg bend right upper leg bend left Four sensors under the foot Sensors (v.1c) 24
  25. 25. Four Force sensors under the foot D Sensors (v.1c) 25
  26. 26. The Nao robot uses force feedback at its feet Sensors (v.1c) 26
  27. 27. Strain Gauge : Force sensors 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
  28. 28. Single element strain gauge sensitive to temperature change. Vb gauge R Gauge=R+∆R rod V0 R R load  R R   ∆R   ∆R   G ∆L V0 = Vb  −  = Vb   ≈ Vb  = Vb   2 R 2 R + ∆R   4 R + 2 ∆R   4R   4 L  ∆R ∆Lfor =G and G = strain gauge factor, L = length of the gauge R LR = unstrained gauge resistance Sensors (v.1c) 28
  29. 29. Four-element (Wheatstonebridge) strain gauge sensor, Four times more sensitive than single gauge system; not sensitive to temperature change. All gauges have unstrained resistance R. t1 t2 Vb b2=R-∆R t1=R+∆R rod V0 b1 b2 t2=R+ ∆R b1=R-∆R load  R + ∆R R − ∆R   2∆ R   ∆L V0 = Vb  −  = Vb   = Vb  G   R + ∆R + R − ∆R R + ∆R + R − ∆R   2R   L  Sensors (v.1c) 29
  30. 30. Flexion (bend) sensors resistance: 10 KΩ (0°); 30-40 KΩ (90°) / Sensors (v.1c) 30
  31. 31. Felixon resistance Demo Sensors (v.1c) 31
  32. 32. Air pressure sensor Measure up to 150 psi (pressure per square inch ). Sensors (v.1c) 32
  33. 33. Position sensors Infra-red range sensor Linear and Rotary position sensors Sensors (v.1c) 33
  34. 34. Infra-red Range detectors by SHARP (4 to 30cm) 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
  35. 35. IR radar using the Sharp rangedetector Sensors (v.1c) 35
  36. 36. Position sensors, from[1] Rotary Linear Optical shaft encoder Sensors (v.1c) 36
  37. 37. Magnetic rotary encoder) non touch sensing Sensors (v.1c) 37
  38. 38. Optical rotary encoder) The light received (on or off) will tell the rotation angle) 3 light receivers Light paths Rotation shaft 3 light emitters Crank shaft sensor Sensors (v.1c) 38 http://www.youtube.com/watch?v=RuIislTGOwA
  39. 39. Temperature and humidity Temperature humidity Sensors (v.1c) 39
  40. 40. Temperature sensorsLM135/235/335 features(from NS) 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
  41. 41. Application note (connecting to anADC e.g. ADC0820 or ADC0801) Sensors (v.1c) 41
  42. 42. Capacitive Atmospheric HumiditySensor BCcomponents 2322 691 90001 10-90%RH Dc Sensors (v.1c) 42
  43. 43. Leaf Sensor Alerts When PlantsAre Thirsty Sensors (v.1c) 43
  44. 44. TSL250, TSL251, TSL252LIGHT-TO-VOLTAGE OPTICAL SENSORS 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
  45. 45. Cadmium Sulfoselenide (CdS)Photoconductive Photocells Light sensing using CdS Sensors (v.1c) 45
  46. 46. Hall effect Sensors for sensingmagnetic flux“B field”, see: Sensors (v.1c) 46
  47. 47. Application on Magnetic levitation 磁懸浮 Magnetic levitation Train Model 磁懸浮火車 frog levitation Sensors (v.1c) 47
  48. 48. Hall effect sensors and brushless DCmotors Brushless DC motor Is it using Hall effect sensor? Dont known. Sensors (v.1c) 48
  49. 49. Novel sensors Kinect / Sensors (v.1c) 49
  50. 50. Many KINECTDIY projects Sensors (v.1c) 50
  51. 51. Control systemsExample: A temperature control system Sensors (v.1c) 51
  52. 52. Control example: Temperature control system computer Digital control TimerWater tank circuit Temp. Sample Sensor Instrum. A/D amp. & Hold CPU Pulse Width Heater modulation D/A & solid state relay Sensors (v.1c) 52
  53. 53. 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). Overshoot Treq Steady state error UndershootTemp On-off control result Time Sensors (v.1c) 53
  54. 54. Temperature control method 2 : Proportional-integral-differential (PID) temperature control (good) Init. (set required temperature Treq) Loop forever{ get temperature T from sensor, Tw e=T - Treq then Tw =e*G*{Kp+Kd*[d(e)/dt] +Ki*∫e dt } Proportional, differential, integral else } //G,Kp,Kd,Ki can be adjusted by user Tw Sensors (v.1c) 54
  55. 55. PID block diagram Kd Kp Figure 1 - Parallel PID block diagram Ki Sensors (v.1c) 55
  56. 56. PID control using pulse widthmodulation PWM Tw (depends on e ) Time Fixed period and fixed number of pulsesTemperature On-off control: oscillates and unstableTreq PID control result of method 2 Time Sensors (v.1c) 56
  57. 57. Summary Studied the characteristics of various sensors and their applications Sensors (v.1c) 57

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