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Adapting Cubic Spline Traj Controller to run on Erratic

asked 2011-07-08 14:23:27 -0500

PKG gravatar image

This is a follow up to my earlier query on cubic splines.

I've got the Cubic Spline controller working on pr2_arm. I want to know how I can strip PR2's files to work with move_base instead, and get the Erratic robot to follow a Cubic spline path. I'm totally in the dark about this, and would like to get your helpful pointers.

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answered 2011-07-10 21:54:48 -0500

I'm totally in the dark

Yes, it seems so. :-)

The cubic spline controller (and all other trajectory controllers) are for robot arms, not for the robot base. That means the trajectories are joint trajectories, not trajectories in 2D or 3D cartesian space. If you want the robot base to follow a trajectory, you basically have to write your own code.

What move_base does is navigation. It provides an action interface that accepts 2D cartesian coordinates. The move_base node will try to reach the coordinate given using local and global path planners, taking the map of the environment into account and avoiding collisions with obstacles. This means you have obstacle avoidance, but you don't have full control over the path that move_base chooses to reach its goal.

So, what do you want? If you want the robot to drive along a series of waypoints while doing obstacle avoidance, and you don't really care about the exact path the robot chooses, use move_base. If you want the robot to follow a spline through a series of waypoints, and you care very much about the path being exactly on that spline, but you don't want obstacle avoidance, write your own code that directly publishes to the cmd_vel topic (see this tutorial).

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Thanks Gunther for showing me the light :-) The move_base thing above is exacty what I did.
PKG gravatar image PKG  ( 2011-07-11 10:29:03 -0500 )edit

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Asked: 2011-07-08 14:23:27 -0500

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Last updated: Jul 10 '11