ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

How the poineer astimate its position in the world?

asked 2014-11-13 08:23:25 -0600

RSA_kustar gravatar image

updated 2014-11-13 08:28:14 -0600


I have been using the Pioneer3AT and I run RosAria in order to get its position but I never understand how ti finds the position and what is the world reference frame to it. When I looked for the explenation I found the following:

(This pose estimation is calculated by the robot firmware as ARIA based on wheel odometry, and if preset, the optional internal gyroscope.)

I also found this as comments in the code of Aria

  • This position is updated by data reported by the robot as it
  • moves, and may also be changed by other program components,
  • such as a localization process (see moveTo()).

  • This position is also referred to as the robot's
  • "odometry" or "odometric" pose, since the robot
  • uses its odometry data to determine this pose; but it
  • may also incorporate additional data sources such as
  • an onboard gyro. The term "odometric pose" also
  • distinguishes this position by the fact that its
  • coordinate system may be arbitrary, and seperate
  • from any external coordinate system.

I didn't understand it ?? is the (0,0) position is the point where we place the robot and we first open it ?? can any one explain please ?

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2014-11-13 08:30:58 -0600

Tom Moore gravatar image

When the robot starts, it assumes it's at (0, 0) and with a heading of 0 (i.e., facing straight down the X-axis). When you start to move the robot, it has sensors, which are known as wheel encoders, that measure the number of rotations its wheels have made, and it uses that information to estimate both how fast it is going and how much it has moved. It can also estimate how fast it is turning and how much it turned using the same information. If you have a P3AT that came with a gyroscope, it uses that information to refine its heading and heading velocity.

edit flag offensive delete link more


Thank you :)

RSA_kustar gravatar image RSA_kustar  ( 2014-11-16 01:44:03 -0600 )edit

Question Tools


Asked: 2014-11-13 08:23:25 -0600

Seen: 311 times

Last updated: Nov 13 '14