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asked 2012-03-27 12:09:51 -0500

allenh1 gravatar image

Hello all,

I am using an arduino to produce acceleration data for a robot without encoders (I know that this is indeed a HORRIBLE idea). I have a small, 2D [x, y], plus or minus 6g accelerometer. I am getting the values by translating it to g's, then multiplying that by 9.80665 to get the m/s^2 readings. So, now that I have this, what do I do with the unfillable values inside a sensor_msgs/Imu message? And, once I do that, will this be able to be filtered in the robot_pose_ekf?


-Hunter A.

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The robot is very small and won't have a possible camera mount.

allenh1 gravatar image allenh1  ( 2012-03-28 11:34:22 -0500 )edit

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answered 2012-03-27 14:00:32 -0500

Kevin gravatar image

You can put them as zeros and give them large covariances. Yes they will be filtered, but to what end? I am not sure you have enough information (2D accelerations) to do much with. You will also need some method to sense orientation, which is the most important. That is usually done with gyros and a 3D accel or perhaps a camera (could give you a rough estimate).

If you are trying to do some strap on inertial nav stuff, this won't be good enough. The accel errors will grow without bounds and your pose will be junk. You said you don't have wheel encoders, but what about video odometry or GPS to attempt to correct the drift.

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I wanted to add to this answer that the robot pose ekf does not use acceleration or velocity data, only position data. So sending acceleration data to the robot pose ekf will do nothing. You have to integrate the acceleration yourself, but this will most likely give horrible results.

Wim gravatar image Wim  ( 2012-04-04 07:35:42 -0500 )edit

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Asked: 2012-03-27 12:09:51 -0500

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Last updated: Mar 27 '12