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RDL VL 03 Sensors

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up:: RDL MOC
tags:: RDL

lecture03-rdl-0.pdf

Sensors in Humans

Sensor Types

Interaction with the environment:

  • Aktive Sensor ⇒ generate stimuli to precive the environment.
  • Passive Sensors ⇒ react to stimuli from the environment.

Measurement representation:

  • Digital sensor ⇒ returns binary (on or off)
  • Analog sensor ⇒ returns continous output signal. eg current

Measured system:

  • Interoceptive sensors - measure internal robot data
    (e.g. motor voltage and current, battery state, temperature).

  • Proprioceptive sensors - measure robot state in the environment
    (e.g. linear and angular position, velocity and acceleration,
    forces and torques).

  • Exteroceptive sensors - measure the environment directly
    (e.g. proximity sensors, camera, pressure).

Sensor Characteristics

  • Range ⇒ maximum and minimum values

  • Sampling Rate ⇒ the average number of measurements over time (in Hz)

  • Reselution ⇒ the smallest ammount that can be detected

  • Accuracy ⇒ the maximum dkifference between the true value and the measured values

  • Quantization Error ⇒ the error created by the digitalization of the measurement

Challenges in Robot Sensing

  • measurement uncertainties
  • deterministic and stochastic noise
  • limited measurement frequency I poor resolution
  • loss of calibration over time
  • sensor failures
  • insufficient storage
  • multimodal data

Sensor Fusion

  • Combining multiple sensors to get better information about the world.
  • Sensor fusion is a complex process:
    • Different modalities.
    • Contradictory information.
    • Different sampling rates (asynchronous perception).
  • Methods: Kalman Filter, Particle Filter, Machine Learning, etc
Link to original

Task: choose Sensores for Drone

Introspective

  • Motor current ⇒ Self diagnosis
  • Motor temperature ⇒ Self diagnosis
  • Battery charge / consumption ⇒ Flight time prediction

Proprioceptive

  • Ineratio mesurment units
    • Accelerometer ⇒ Flight stability
    • Gyroscope ⇒ Flight stability
  • GPS ⇒ Broad Navigation
  • Barometer ⇒ Height Sensor

Exteroceptive

  • 3D Lidar poited to the ground. ⇒ Lidar SLAM
  • Camera ⇒ Visual SLAM
  • Infrared camera ⇒ Search and Assist tasks.

next: RDL VL 04 Odometry

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