RDL VL 03 Sensors

up:: RDL MOC
tags:: uni/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