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Permalink Reply by John Leichty on October 2, 2011 at 12:18pm

It sounds like you might be trying to do what robotic vacuum cleaners do on carpet, but for ice.

 

At a minimum you need a way to control the two wheels independently -- it's common to have a motor/gearbox/encoder assembly for each wheel. That lets you sense and control rotation angle and rotation velocity of the wheel. This would allow you to "dead reckon" a path across the ice, where the robot would blindly execute a set of drives and turns. Dead reckoning probably won't be good enough, because it relies on a very accurate starting position and heading, and the wheels are bound to slip inconsistently relative to the ice.

 

So, you need some kind of feedback on the motion. The easiest would be to physically draw the path on the ice, and have a simple line-following robot, but that's probably not an option. You could put an IMU+compass on it, and maybe do a good enough job dead-reckoning it to make it work. Another idea is an optical flow sensor close to the ice (basically a computer mouse for ice), no idea how well that would work. You could do a vision system to get the job done, but that would be difficult and expensive.

 

If you draw out a picture of what you want the patterns to look like, or show a video of a human doing the job that you want to automate, we might get a better idea of the problem and possible solutions.

 

P.S. You posted in the wrong forum. :-P

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Permalink Reply by Bill Wood on October 2, 2011 at 3:38pm

John,

 

Thanks for the input. You are correct the ice is an issue for traction. I have thought of burring a wire in the ice so that a simple prox sensor would pick it up. That could be a long term solution. The other thing that I was thinking was to put some sort of a roto pulsor castor wheel. 

 

I will find a video and get back to you.

 

Thanks for the reply.

 

What forum should I be on? I am new at DIY Drones, having a little trouble working my way around the site.

 

Thanks

 

Bill

 

 

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Permalink Reply by John Leichty on October 2, 2011 at 10:55pm

If modifying the "terrain" is possible, then this might get a little bit easier. I don't know much about ice-scraping, but if a random pattern is fine, as long as you cover the whole area, then a Roomba-style strategy would work. (see here for a comparison of random versus planned vacuum paths)

 

This discussion probably belongs in the "Ground Vehicles" category:

http://www.diydrones.com/forum/categories/ground-vehicles/listForCa...

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