Sensor for robots

Sensors for Robots
An overview
Václav Hlaváč
Czech Technical University in Prague
Faculty of Electrical Engineering
Department of Cybernetics
Czech Republic http://cmp.felk.cvut.cz/~hlavac Courtesy to several authors of presentations on the web.

Lecture outline
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Note: students graduated from the bachelor KyR studied sensors in the course Sensors and
Measurement. This subject was not specialized to robotics. 
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Motivation, why robots need sensors?
Robotic sensor classification.
Proprioception in humans.
Various sensors overview.

Where are the forkholes?
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Autonomous forklift for material handling

Will robot hit anything?
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Obstacle detection

Where is the cropline?
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Autonomous harvesting

Where am I ?
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Localization in the environment

Robot sensors, generally
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 Sensor constitute robot’s window to the environment.  A robot needs sensing to be an active participant in the environment.
 Each sensor is based on a transduction principle, i.e. a conversion of energy from one form to another.
 Sensors measure a physical quantity, they do not provide state.

Classification of sensors
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 Proprioceptive (“sense of self”, internal state). • Measures values internally to the system
(robot), e.g. battery level, wheel position, joint angle, etc.

 Exteroceptive (external state).
• Observations of robot environment, objects in it.

 Active (emits energy, e.g. radar) vs.
 Passive (passively receives energy, e.g., camera). General sensor classification
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General sensor classification 2
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Characterizing sensor performance
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 Measurement in real world environment is error prone.
 Basic sensor response ratings:
• Dynamic range: Ratio between lower and upper limits, usually in decibels.
• Range: Difference between min and max.
• Resolution: Minimum difference between two values.
• Linearity: Variation of output signal as function of the
input