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odometry navigation

asked 2013-07-10 13:19:54 -0500

salime gravatar image

updated 2016-10-24 09:02:42 -0500

ngrennan gravatar image

I want to implement the navigation in a two wheeled robot with the ROS navigation-package using Kinect , How can I calculate the odometry if I have the radius, the wheeled distance, the poses and the velocity of the wheels???

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answered 2013-07-10 20:18:45 -0500

Odometry can be calculated by estimating "forward kinematics" of mobile robot. Here is a link for one such explanation http://www.cs.columbia.edu/~allen/F11/NOTES/icckinematics.pdf

Hope this helps...

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Thank you... it helped me a lot, but just one question Given that vr= velocity of the right wheel, vl=velocity of the left wheel, R=the signed distance from the ICC to the midpoint between the wheels...

When vr=vl, R becomes infinite and there is no rotation, so how can I manage this situation?

salime gravatar image salime  ( 2013-07-12 08:35:04 -0500 )edit

When vr=vl, the robot should move straight, as you mentioned there will be no rotation.

ayush_dewan gravatar image ayush_dewan  ( 2013-07-12 09:05:58 -0500 )edit

So, is it ok for the navigation if I keep receiving nan (not a number) values in the equations, I have tried asigning a really big number when I get nan, but of course in some cases this won't work because of the overflow. Do you know how can I control this part?

salime gravatar image salime  ( 2013-07-19 08:04:58 -0500 )edit

I am not sure about this, but one thing you can do is not calculate R when difference between vr and vl is very less.

ayush_dewan gravatar image ayush_dewan  ( 2013-07-19 19:03:18 -0500 )edit

Thank you for your reply, I did that, the R thing, and now looks like the nan is gone, but the final pose (x,y, theta) keeps getting bigger and bigger when I start moving the robot, even though when I stop moving it.. it keeps getting bigger and bigger in the x, y and theta, and of course these values are not correct for the pose

salime gravatar image salime  ( 2013-07-22 11:35:00 -0500 )edit

I have done some tests in the particular case when vl !=0 and vr != 0, incrementing the x, y, ant theta just in these cases, but the results do not look correct either

salime gravatar image salime  ( 2013-07-23 08:20:02 -0500 )edit

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Asked: 2013-07-10 13:19:54 -0500

Seen: 179 times

Last updated: Jul 10 '13