DWA Planner gives y velocities although y is set to 0

edit

UPDATE:

I checked the DWA Planner wiki page once more and took a look at the subscribed and published topics. I have now discovered a difference between the STAGE simulation and my real robot: The simulation gives odometry twist msg with linear.x and angular.z data. My real robot publishes odometry twist messages with linear.x and linear.y data.

Is it possible that this is causing the problem?

Hello everybody,

i'm writing my masterthesis. We habe a nonholonomic robot (diff-drive) with his base_link 10cm behind the centre of the robot. We use Hydro and i want to get the Navigation-Stack to work.

Everything works fine, just the DWA-Planner makes some trouble. First I simulated everything with STAGE and the DWA Planner worked well. I set all the parameters for the y-velocity to 0 because of the diff-drive. Now I want to run the DWA Planner on the robot with the same parameters, but the robot gets y-velocities (i can see them on the /cmd_vel topic) and because of that the robot doesn't drive properly. Both systems are running Hydro and the version of the DWA_Planner is the same.

I don't understand why the simulated system is working and the real system has some troubles with the DWA.

Here is my dwa_planner yaml file:

DWAPlannerROS:
  max_trans_vel: 0.8       
  min_trans_vel: 0.05      

  max_vel_x: 0.2      
  min_vel_x: 0.05  

  max_vel_y: 0 
  min_vel_y: 0  

  max_rot_vel: 0.5  
  min_rot_vel: 0.0  

  acc_lim_theta: 5.0  # 3.2 
  acc_lim_x: 5.0    # 2.5
  acc_lim_y: 0   # 2.5
  acc_lim_trans: 5.0   # 

# Goal Tolerance Parameters
  yaw_goal_tolerance: 0.17    # 0.05
  xy_goal_tolerance: 0.2    # 0.10


# Forward Simulation Parameters
  sim_time: 1.7   
  vx_samples: 5 
  vy_samples: 0    
  vtheta_samples: 20  

  meter_scoring: true  
  penalize_negative_x: false  

# Oscillation Prevention Parameters
  oscillation_reset_dist: 0.05  

# Debugging
  publish_traj_pc : true
  publish_cost_grid_pc: true
  global_frame_id: map

# Is this existing?
  sim_granularity: 0.025     
  goal_distance_bias: 32.0   
  path_distance_bias: 24.0   
  occdist_scale: 0.3         
  stop_time_buffer: 0.2      


  forward_point_distance: 0.000 
  scaling_speed: 0.25           
  max_scaling_factor: 0.2       


  rot_stopped_vel: 0.01 
  trans_stopped_vel: 0.01

Here is my move_base launch file:

<launch>
<!-- Use DWAPlannerROS -->
<param name="/move_base/base_local_planner" value="dwa_local_planner/DWAPlannerROS" />

<!-- move_base -->
<node pkg="move_base" type="move_base" respawn="false" name="move_base" output="screen">

    <rosparam file="$(find prai_dsc)/param/costmap/dwa_local_planner_params.yaml" command="load" />
    <rosparam file="$(find prai_dsc)/param/costmap/costmap_common_params.yaml" command="load" ns="local_costmap" />
    <rosparam file="$(find prai_dsc)/param/costmap/local_costmap_params.yaml" command="load" ns="local_costmap"/>

    <rosparam file="$(find prai_dsc)/param/costmap/costmap_common_params.yaml" command="load" ns="global_costmap" />
    <rosparam file="$(find prai_dsc)/param/costmap/global_costmap_params.yaml" command="load" ns="global_costmap" />

 </node></launch>