amcl_pose vs odom/pose

asked 2016-09-11 14:22:00 -0500

Miguel Velez
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Hi,

What is the difference between amcl_pose and odom/pose? I am running the gazebo simulator and making the turtlebot go from one point to another. The task completes without any issues. However, the pose values in each of these topics do not match. They are sort of close, but are definitely not THAT close. Is it one the REAL position of the turtlebot and the other one where the actual robot thinks it is?

Thanks!

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answered 2016-09-11 22:19:28 -0500

Shay

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Well, /odom/pose is the relative pose, /amcl/pose is the absolute pose.

The odometry knows how far your robot has gone and how much the angle of rotation, and calculate the position and orientation for you. But odometry is only right for a short time because of slipping and accumulated error.

amcl uses a particle filter to track the pose of a robot against a known map. amcl gets the absolute or global pose of the robot and fix the tf map->odom to make the robot pose right. You can consider amcl as the REAL pose. And amcl is responsible to fix the error of odometry.