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Hi, I'm trying to get familiar with SMACH and adapting tutorial, but changing default dwa_local_planner to DWB, since it showed a great performance.

Since It's nav_core, I'm using nav_core_adapter, loading DWB_local_planner as:

  - name: 'BaseLocalPlanner'
    type: 'nav_core_adapter::LocalPlannerAdapter'
  planner_name: dwb_local_planner::DWBLocalPlanner
  update_frequency: 5.0

While running move_base_flex, all the things are loaded without errors, but when choosing a goal, I'm getting a lot of :

[ERROR] []: computeVelocityCommands exception: No valid trajectories out of 0!

Any clue what the reason could be? Am I missing something in SMACH python file?

[EDIT 1]:

planner_ns/evaluation output is a good debugging tool, thanks @David Lu

Output this message:

frame_id: "odom_combined"
twists: []
best_index: 0
worst_index: 0

I found his thread. If I got it right, planner is waiting for /odom topic, but by defalult it's publishing /odom_combined.

Also, local and global planner parameter's global map: set to map in common_parameters.yaml, which needs to be set as odom for local_planner_params.yaml. The last, pay attention to the velocity, as it's explained in the link.

Originally posted by artemiialessandrini on ROS Answers with karma: 69 on 2020-05-19

Post score: 0

Original comments

Comment by artemiialessandrini on 2020-05-20:
GetPath.action, ExePath.action explained at 294278/custom-global-path/

Comment by David Lu on 2020-05-20:
Can you capture the output of planner_ns/evaluation in a bag and post it?

Comment by artemiialessandrini on 2020-05-21:
I updated a thread, thanks again! @David Lu


1 Answer 1


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See [EDIT] in the header

  1. capture the output of planner_ns/evaluation
  2. Follow this thread:
  1. pay attention odom to be set as global_frame in local_costmap_params.yaml
  2. have /odom topic
  3. have planner set using nav_core_adapter as explained in description locusrobotics/robot_navigation/nav_core_adapter

Originally posted by artemiialessandrini with karma: 69 on 2020-05-21

This answer was ACCEPTED on the original site

Post score: 1

Original comments

Comment by David Lu on 2020-06-05:
Glad it worked out for you.


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