Subject:
|
Re: Robot Mapping
|
Newsgroups:
|
lugnet.robotics.handyboard
|
Date:
|
Fri, 26 Mar 1999 01:05:34 GMT
|
Original-From:
|
Steve Chamberlin <SLC@PACBELLspamcake.NET>
|
Reply-To:
|
slc@alum.mit.(nomorespam)edu
|
Viewed:
|
878 times
|
| |
|
|
michael lang kee wrote:
>
> Hello, I am working on an autonomous mobile robot. Which has a sonar and
> infared sensor incorporated into it. Right now it can avoid objects, by
> sensing it and backing up and turning. I want my robot to take the
> information from the sensors and map out the terrain. I want to know if
> anyone has an algorithm for mapping the terrain. The coding doesn't
> matter, I can transform it into code I can use.
I've been thinking about this too. The problem as I see it is that
without some shaft encoders on the wheels, your robot doesn't really
know how far it's moved, and therefore where it is in the map. If you
power on the forward motor for 2 seconds, bump something, and go reverse
for 2 seconds, where are you? Probably somewhere close to where you
started, but not exactly. All of those "not exactly" errors will quickly
add up over many iterations of forward, back, turn, etc. until the robot
has basically no idea where it is relative to its starting position.
Bottom line: you really need a way to calculate how far you've moved, or
even better an external positional reference, to have much hope of
mapping.
Assuming you can solve that problem, here's an approach that's probably
far from optimal, but it should work. Divide your area to be mapped into
grid units, with the size of one grid unit being the size of your robot.
Then do a depth-first search of the grid units:
while (!all_grids_units_explored)
{
if (unexplored_neighboring_grid_unit_exists())
go_to_unexplored_neighboring_grid_unit();
else
return_to_previous_grid_unit();
}
This method will eventually attempt to enter every grid unit, so you can
tell which grid units contain obstacles using the sensors. It should be
able to find its way through any complex "maze" of obstacles too, at
least in theory.
--Steve
|
|
Message is in Reply To:
 | | Robot Mapping
|
| Hello, I am working on an autonomous mobile robot. Which has a sonar and infared sensor incorporated into it. Right now it can avoid objects, by sensing it and backing up and turning. I want my robot to take the information from the sensors and map (...) (25 years ago, 25-Mar-99, to lugnet.robotics.handyboard)
|
6 Messages in This Thread:
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
