velocity smoother deadband velocity broken since 1.1.7

[Aposhian]

Bug report

Required Info:

• Operating System:
  • Ubuntu 22.04
• ROS2 Version:
  • Humble binaries
• Version or commit hash:
  • 1.1.8
• DDS implementation:
  • N/A

Steps to reproduce issue

ros2 run nav2_velocity_smoother velocity_smoother --ros-args -p 'deadband_velocity:=[0.25,0.0,0.0]'

In a separate terminal:

ros2 lifecycle set /velocity_smoother configure && ros2 lifecycle set /velocity_smoother activate
ros2 topic pub -r 20 /cmd_vel geometry_msgs/msg/Twist '{ linear: { x: 0.5 }}'

In a separate terminal:

ros2 topic echo /cmd_vel_smoothed --field linear.x

Expected behavior

It works on 1.1.6. /cmd_vel_smoothed.linear.x ramps up to full speed (0.5 in this case).

Actual behavior

On 1.1.8. /cmd_vel_smoothed.linear.x stays at 0 forever.

Additional information

I believe this was broken in 1.1.7 because the last_cmd_ is set after the deadband velocities are applied. This means that the last_cmd is clamped to 0 forever.

https://github.com/ros-planning/navigation2/blob/da5edbfd12efd0ba74cd6bb6bc8c8ad8ca9bd88a/nav2_velocity_smoother/src/velocity_smoother.cpp#L308

Workaround is to disable deadband_velocity.

Also, I think this only affects open loop mode.

[BriceRenaudeau]

Sorry, the fix is here soon :#3690

[SteveMacenski]

Merged! Backporting to iron / humble shortly