25-09-2012, 01:41 PM
Overview of Our Sensors For Robotics
[attachment=34556]
What is Sensing ?
Collect information about the world
Sensor - an electrical/mechanical/chemical device that maps an environmental attribute to a quantitative measurement
attribute mixtures - often no one to one map
hidden state in environment
Each sensor is based on a transduction principle - conversion of energy from one form to another
Also known as transducers
Types of Sensors
Active
send signal into environment and measure interaction of signal w/ environment
e.g. radar, sonar
Passive
record signals already present in environment
e.g. video cameras
Classification by medium used
based on electromagnetic radiation of various wavelengths
vibrations in a medium
concentration of chemicals in environment
by physical contact
Encoders
Encoders measure rotational motion.
They can be used to measure the rotation of a wheel.
Servo motors: Used in conjunction with an electric motor to measure the motor’s position and, in turn, control its position.
Sensors Based on EM Spectrum
Basically used for ranging
Light sensitive
eyes, cameras, photocells etc.
Operating principle
CCD - charge coupled devices
photoelectric effect
IR sensitive - FLIR
sense heat differences and construct images
night vision application
EM Spectrum
Radio and Microwave
RADAR: Radio Detection and Ranging
Microwave radar: insensitive to clouds
Coherent light
all photons have same phase and wavelength
LASER: Light Amplification by Stimulated Emission of Radiation
LASER RADAR: LADAR - accurate ranging
Sensors Based on Sound
SONAR: Sound Navigation and Ranging
bounce sound off of something
measure time for reflection to be heard - gives a range measurement
measure change in frequency - gives the relative speed of the object (Doppler effect)
bats and dolphins use it with amazing results
robots use it w/ less than amazing results
Proprioceptive Sensors
Encoders, Potentiometers
measure angle of turn via change in resistance or by counting optical pulses
Gyroscopes
measure rate of change of angles
fiber-optic (newer, better), magnetic (older)
Compass
measure which way is north
GPS: measure location relative to globe
[attachment=34556]
What is Sensing ?
Collect information about the world
Sensor - an electrical/mechanical/chemical device that maps an environmental attribute to a quantitative measurement
attribute mixtures - often no one to one map
hidden state in environment
Each sensor is based on a transduction principle - conversion of energy from one form to another
Also known as transducers
Types of Sensors
Active
send signal into environment and measure interaction of signal w/ environment
e.g. radar, sonar
Passive
record signals already present in environment
e.g. video cameras
Classification by medium used
based on electromagnetic radiation of various wavelengths
vibrations in a medium
concentration of chemicals in environment
by physical contact
Encoders
Encoders measure rotational motion.
They can be used to measure the rotation of a wheel.
Servo motors: Used in conjunction with an electric motor to measure the motor’s position and, in turn, control its position.
Sensors Based on EM Spectrum
Basically used for ranging
Light sensitive
eyes, cameras, photocells etc.
Operating principle
CCD - charge coupled devices
photoelectric effect
IR sensitive - FLIR
sense heat differences and construct images
night vision application
EM Spectrum
Radio and Microwave
RADAR: Radio Detection and Ranging
Microwave radar: insensitive to clouds
Coherent light
all photons have same phase and wavelength
LASER: Light Amplification by Stimulated Emission of Radiation
LASER RADAR: LADAR - accurate ranging
Sensors Based on Sound
SONAR: Sound Navigation and Ranging
bounce sound off of something
measure time for reflection to be heard - gives a range measurement
measure change in frequency - gives the relative speed of the object (Doppler effect)
bats and dolphins use it with amazing results
robots use it w/ less than amazing results
Proprioceptive Sensors
Encoders, Potentiometers
measure angle of turn via change in resistance or by counting optical pulses
Gyroscopes
measure rate of change of angles
fiber-optic (newer, better), magnetic (older)
Compass
measure which way is north
GPS: measure location relative to globe