Filtering trajectory (position and velocity) ignores velocity information [closed]

asked 2013-05-03 10:33:24 -0500

agmenon gravatar image

updated 2014-11-22 17:05:35 -0500

ngrennan gravatar image

Hi, I want to do kinodynamic planning with the PR2 so I want to figure out how I should handle position-velocity waypoints of a trajectory.

I created a simple 3-point trajectory, moving one joint, and set the mid points velocity to be half the max joint velocity, using the tutorial on trajectory filters (

And subsequently tried to filter this trajectory as well in order to get proper time parametrization in the time_from_start field. I found that even though I specified velocities at each waypoint, it would ignore them and change them.

Since I was using spline_smoother package and in the docs it says:

This package takes in position trajectories (with times), and can fill in velocities and accelerations at the knot points using various schemes, like numerical differentiation, clamped cubic splines, or the Fritsch-Butland monotonic cubic interpolator.

The filters in it were designed to ignore the velocities specified.

Which lead me to look at this package: constraint aware spline smoother And to try launching with service_type: FilterJointTrajectoryWithConstraints

But I can't get it to launch, because the trajectory_filter process dies after giving these warnings:

[ WARN] [1367611024.536438004, 10543.027000000]: No multi dof joints specified, including root to world conversion
[ WARN] [1367611024.540077642, 10543.027000000]: No groups for planning specified in /robot_description_planning/groups
[ WARN] [1367611024.540886053, 10543.027000000]: Can't do anything without a root transform
[ WARN] [1367611024.546978448, 10543.027000000]: No default collision operations specifiedoperations specified

My basic question is: How do I launch the trajectory filter server and configure it to take a position-velocity trajectory and re-time it?

Thanks, Arjun

edit retag flag offensive reopen merge delete

Closed for the following reason question is not relevant or outdated by tfoote
close date 2016-06-16 19:28:52.566836