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How to avoid "Invalid Trajectory (cost: -1.000000)" in DWA Local Planner? [closed]

asked 2015-06-23 13:28:15 -0600

updated 2015-06-25 12:00:31 -0600

Dear all,

I am using DWA to drive a differential robot around. I am running Ubuntu 12.04 and ROS Hydro.

In general, the robot navigates well. However, sometimes when I send it to tight spots, I receive the following warnings:

[ WARN] [1435079055.081046415]: Invalid Trajectory 0.000000, 0.000000, 0.822608, cost: -1.000000
[ WARN] [1435079056.578828210]: Invalid Trajectory 0.000000, 0.000000, 0.931650, cost: -1.000000
[ WARN] [1435079058.079198312]: Invalid Trajectory 0.000000, 0.000000, 0.850638, cost: -1.000000
[ WARN] [1435079058.580604641]: Invalid Trajectory 0.000000, 0.000000, 1.000000, cost: -1.000000
[ WARN] [1435079060.483851910]: Invalid Trajectory 0.000000, 0.000000, 0.400000, cost: -1.000000

While receiving these warnings, the robot stands still, and eventually starts doing recovery behaviors, aborting most of the time afterwards.

My questions:

  • What is causing these invalid trajectories with cost: -1?
  • How can I avoid them?

Below, my "base_local_planner_params.yaml" file:

TrajectoryPlannerROS:
  max_vel_x: 0.8        
  min_vel_x: 0.2
  max_vel_y: 0.0        
  min_vel_y: 0.0  
  max_vel_theta: 2.0
  min_vel_theta: -2.0 
  min_in_place_vel_theta : 0.65
  escape_vel: -0.1

  acc_lim_theta: 3.2    
  acc_lim_x: 2.5        
  acc_lim_y: 0.0                       

  holonomic_robot: false

  sim_time: 1.5
  sim_granularity: 0.025 
  angular_sim_granularity: 0.025
  vx_samples: 5                         
  vy_samples: 0
  vtheta_samples: 20
  meter_scoring: false                 

  yaw_goal_tolerance: 0.2              
  xy_goal_tolerance: 0.25              
  latch_xy_goal_tolerance: false        
  gdist_scale: 0.5                      
  pdist_scale: 0.7                      
  occdist_scale: 0.02        

  dwa: true

Here is a video of the robot's behavior: https://youtu.be/Y-zro-sXO-o

Let me know if further details are necessary. Thanks in advance!

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Closed for the following reason question is not relevant or outdated by Procópio
close date 2017-07-17 02:05:40.143137

Comments

How are you specifying the footprint?

David Lu gravatar imageDavid Lu ( 2015-06-25 12:31:04 -0600 )edit

Here it is: footprint: [[0.15,0.22],[0.15,-0.22],[-0.55,-0.22],[-0.55,0.22]]
it's a rectangle around the robot.

DavidPortugal gravatar imageDavidPortugal ( 2015-06-25 13:21:14 -0600 )edit

I've been playing around with the vx_samples and vtheta_samples lately, but still without success.

DavidPortugal gravatar imageDavidPortugal ( 2015-06-30 09:23:21 -0600 )edit

Hi David (Portugal), did you end up finding a way to make DWA "behave"? Thanks!

spmaniato gravatar imagespmaniato ( 2016-03-03 14:11:39 -0600 )edit

Unfortunately no @spmaniato. The problem wasn't critical, and the robot would recover eventually.

DavidPortugal gravatar imageDavidPortugal ( 2016-03-04 03:03:43 -0600 )edit

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answered 2015-06-23 14:03:46 -0600

David Lu gravatar image

It means that it can't find any valid plan. Invalid plans have negative costs.

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Comments

Yes, I am aware of that, thanks. The issue is: What is causing the generation of invalid plans and how can I avoid it? Do you see anything in the parameters that should not be there and might cause this?

DavidPortugal gravatar imageDavidPortugal ( 2015-06-24 06:26:03 -0600 )edit

To figure that out, you need to be more explicit about what the tight spot actually looks like in relation to your robot.

David Lu gravatar imageDavid Lu ( 2015-06-24 08:27:55 -0600 )edit

Thank you David, I've added a video showing the robot's behavior in the original question.

DavidPortugal gravatar imageDavidPortugal ( 2015-06-25 12:01:24 -0600 )edit

Hi i m facing the same problem! Did you find any solution

SH_Developer gravatar imageSH_Developer ( 2017-07-04 07:39:12 -0600 )edit

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Asked: 2015-06-23 13:28:15 -0600

Seen: 788 times

Last updated: Jun 25 '15