Society of Robots - Robot Forum

General Misc => Misc => Topic started by: SeagullOne on April 08, 2008, 10:10:51 PM

Title: Compassing
Post by: SeagullOne on April 08, 2008, 10:10:51 PM
Hi everyone. Not sure if this is the right forum to post on, but, here it goes! ;D

Thanks to all your help, my project is going smoothly. I've built a good solid base for my bot with motors and some circuitry attatched. The battery I bought doesn't fit anymore, so I'll have to buy something smaller... :'(

Anyway, getting to the point, I want my robot to navigate around my house using a compass and the wavefront algorithm. But if one of my destinations is the refrigerator, (or if my robot has to go by the fridge), won't that mess up her compassing? I know mortors and servos can do this too, so I'm putting the electronic compass as far away from those as possible. Still, I'd imagine the refrigerator would mess it up anyway.

Should I just use some extra money and purchase a GPS unit instead? If so, what kind of GPS unit would you recommend? Can a GPS unit be used to nagivate around the small confines of a house, or is it just practical to use one on the road?

Thanx a lot!
Title: Re: Compassing
Post by: skatj on April 09, 2008, 03:11:39 AM
GPS won't usually work indoors, and even if it does, the GPS resolution is like 5 meters depending on how much you spend on it, which is too big to navigate in a house-sized area.

Compass would probably be better for your application
Title: Re: Compassing
Post by: Admin on April 25, 2008, 08:54:14 AM
SeagullOne, this is actually a very hard problem to solve - even experts have had little luck with this.

Instead, you need to backtrack and ask yourself what you really want the robot to do. You don't want it to map, you want it to find its way around the house - two very different things!

Of course, mapping could be a possible solution, but I'd argue its too difficult (and perhaps hopeless) for a long list of reasons I'd rather not get into.

Instead, you want your robot to avoid objects in the way, and identify objects to move towards - such as a fridge.

Object avoidance can be easily achieved with basic sensors and a basic algorithm, like on my $50 Robot. Object identification would be best done by using well placed beacons, and/or vision:
http://www.societyofrobots.com/programming_computer_vision_tutorial.shtml

Its also very similar to this frequently asked question:
http://www.societyofrobots.com/robot_faq.shtml#robot_track_person