Re: Localization of A Omni-Directional Robot
 

I hate to plant this seed in someone's brain, but it MIGHT be possible to have a robot go from (x1, y1) to (x2, y2) using just an accelerometer. It is something I am investigating in my lab at college. Basically you construct the problem in terms of acceleration and the robot learns how to make the accelerometer read that acceleration. The idea is that if the robot gets so good at going x ft/sec^2 for any possibly x and can adjust from it's current acceleration a - > x in a reasonable time, then it is possible. However, as others have pointed out in this thread, error accumulates extremely quickly. This program will have to be flawless in its transitions.

It is a deeper investigation in my original project with a robot teaching itself how to follow a path given velocities. I am without a robot until I go back to college in August, however.

This project should be finished by next fall....with a paper submitted for publication sometime late next year.

Re: Localization of A Omni-Directional Robot
 

How are you dealing with noisy/unreliable signals? This has always been a problem in my experience.

Re: Localization of A Omni-Directional Robot
 

That's where it gets iffy. It relies entirely on 100% accurate sensor data as well as getting data as fast as possible. I was thinking about having *3 accelerometers and averaging them. I expect it get somewhat close to the target spot, but I wouldn't put money on it in a precision contest.

*I would like to have about 20 just to really solidify the data, but that is unreasonable. If I would do that, however, I would use a RANSAC algorithm to find the "mean" of the signals. Also, it'd look pretty silly having a tower of accerlometers on a robot that is 6 inches tall.

Re: Localization of A Omni-Directional Robot
 

I'd wager for typical FRC level precision you'd always be happier with encoders (possibly on non-driven idler wheels) and gyro.

Re: Localization of A Omni-Directional Robot
 

Or a vision program that solves for the pose of a static object in the field, which gives you your position on the field.

But yes, encoders and gyro would be the easiest, and probably the most accurate, approach by far.

Re: Localization of A Omni-Directional Robot
 

lol put a spinning radar satellite on your robot... :D

Re: Localization of A Omni-Directional Robot
 

There are sub-$100 LIDAR units like the LIDARLite which if put on a servo can scan the field at every 2 degree increment in about 2-3 seconds. Advantage is they are very fast, and can range up to 40 meters w/an accuracy of +/1 one inch. Unfortunately, the side panels of the FRC field are polycarbonate and most of the IR passes through, so getting a return on significant portions of the field is problematic. If the side-walls of a FRC field were IR opaque, this could potentially yield enough data to triangulate with, assuming the software were to know the field dimensions.