Integrating GPS and other sensors for autonomous travel
Chassiz
Posts: 1
Hello this is my first post, but my school and I have been buying Parallax products for a while now. Currently we are working on the development of an autonomous wheelchair, but we have sort of run into a snag. Right now we are trying to test the Parallax GPS Receiver Module in an effort to figure out really how it works and how we can use it and other GPS systems in the future. Our question is, with this GPS system, can we input coordinates and use it for navigation? Does this GPS tell us where we went, or can we tell it where to go? Thanks
Comments
Like any GPS System our module tells you where you are at the moment you retrieve the coordinates. It is up to your program to decide-based on where you want to go, how to get there. If you look up the Robo-Magellan competitions they usually use way-points of known coordinates and the robot knows where it is, so based on where it needs to be it uses math to calculate a bearing. All this happens while avoiding obstacles that may be in the way. You will need to study this in order to create something similar. Take care.
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Chris Savage
Parallax Tech Support
Controlling something in a confined space might be a problem as the standard GPS (un-corrected) accuracy is about 3 meters. Indoors could reduce the accuracy due to less satelites. The GPS only 'know' its position nothing more. The supporting systems will evaluate the current position against the previous position and 'detect' movement. The area where the wheelchair should operate must be 'mapped' with waypoints against which the current position and the target position will be evaluated and the course be calculated. The basic 'steering' will be similar to the robot following a line.
If the wheelchair is to be used in a confined space (house) with fixed routes it might be possible to embed a wire in the floor and use a sensor to 'track' the wire. RFID tags and reader could indicate waypoints. A more elaborate option is to use radio senders and a scanning receiver to calculate the position via triangulation.
Cheers