Sensor Fusion Donald Heer 11/10/10. The Questions Can two things happen at the same time? Can the...
-
Upload
oswin-miles -
Category
Documents
-
view
216 -
download
0
description
Transcript of Sensor Fusion Donald Heer 11/10/10. The Questions Can two things happen at the same time? Can the...
Sensor Fusion
Donald Heer11/10/10
The Questions
Can two things happen at the ‘same’ time?Can the same thing be observed ‘identically’ by two different observers?
Example
You are designing a system that measures ‘instantaneous power’ of a AC circuit. You are using a current sensor and a voltage sensor fed into a microcontroller. Can you display ‘instantaneous power’?Discuss in your groups
What Contributes to Timing Error?
ADC Timing Microcontroller ProcessingWire delay
Does it even matter though? Discuss.
What is ‘instant enough’?
Depends on specifications
Another Example
You are tasked with building a dead reckoning device. This system has a digital compass, a GPS, a 3 axis accelerometer, and a 3 axis gyroscope. The device will be installed on an off road buggy the can reach speeds of 60mph.
Specifics
GPS – Accurate with in 10M, 10Hz refreshAccelerometers – Accurate with in .001Gs, 1KHz refresh rateGyroscopes – Accurate within .1ft/sec/sec, 1KHz refresh rateDigital Compass – accurate with in 1 degree, 100Hz refresh rate
Come up with some rules to combine these inputs into a single ‘picture’ of where the buggy is. Discuss
Which Sensors are More Useful?
GPS? Only on rough terrain or when moving fastAccelerometers? Update fast, but noisyGyroscopes? Measures rotation, but drifts over timeDigital Compass? Only gives direction
Take Away
Be sure you know if you need ‘simultaneous’ measurements, or what error you can acceptIf needed, use one sensor to confirm another