Navigation stack on youBot

Question

Hi everybody, I am developing my final thesis using a KUKA youBot. I am managing to run the navigation stack on it, after many attempts, everything seems to work (no warning, no errors), but when I give through rviz a navigation goal this is what happens

http://www.youtube.com/watch?v=EjOxJTRCj7s

The green path is the full plan for the robot (topic: NavfnROS/plan), while the red path is the portion of the global plan that the local planner is currently pursuing (TrajectoryPlannerROS/global_plan). There should be also TrajectoryPlannerROS/local_plan in black, but it is not visible.

Here are the configuration files I am using:

costmap_common_params.yaml

obstacle_range: 2.5
raytrace_range: 3.0
footprint: [[0.290,0.190], [0.290,-0.190], [-0.290,-0.190], [-0.290,0.190]]
#robot_radius: ir_of_robot
inflation_radius: 0.55

observation_sources: laser_scan_sensor

laser_scan_sensor: {sensor_frame: base_laser, data_type: LaserScan, topic: scan\
, marking: false, clearing: false}

#point_cloud_sensor: {sensor_frame: openni_rgb_optical_frame, data_type: PointC\
loud2, topic: camera/rgb/points, marking: false, clearing: false}
--------------------------------------------

global_costmap_params.yaml

global_costmap:
  global_frame: /map
  robot_base_frame: /base_footprint
  update_frequency: 5.0
  publish_frequency: 2.0
  static_map: true
  transform_tolerance: 0.8
(If a use a lower tolerance I obtain the warning concerning the costmap2dros transform timeout )
-----------------------------

local_costmap_params.yaml

local_costmap:
  global_frame: odom
  robot_base_frame: base_footprint
  update_frequency: 5.0
  publish_frequency: 2.0
  static_map: false
  rolling_window: false
  width: 6.0
  height: 6.0
  resolution: 0.10
  origin_x: 10
  origin_y: 10

---

base_local_planner_params.yaml

TrajectoryPlannerROS:
  max_vel_x: 0.07
  min_vel_x: 0.05
  max_rotational_vel: 0.07
  min_in_place_rotational_vel: 0.05

  acc_lim_th: 4.0
  acc_lim_x: 3.7
  acc_lim_y: 3.5

  yaw_goal_tolerance: 0.2
  xy_goal_tolerance: 0.2

  holonomic_robot: true
  y_vels: [-0.1, -0.05, 0.05, 0.1]

  dwa: true

The navigation is blind because in the task involved will not be dynamic obstacles, the only ones are the work space walls.

Am I missing something? What possibly is going wrong?

Thank you so much for the help

Lorenzo

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Originally posted by Lorenzo on ROS Answers with karma: 76 on 2011-09-07

Post score: 0

Answer 1

There are a couple of problems that I see in your parameter set:

1. If you really do intend to avoid obstacles based only on localization and a static map, you'll need to make sure that the local costmap is set up to run with that information. Otherwise, the local planner won't know about those static obstacles. If the map is small, you'll probably just be able to have the local costmap have the same parameters as the global costmap. However, if the map is going to be large, you'll probably want to feed the local costmap tiles of the global map to make sure computing the cost function for the map doesn't get too expensive.

2. The velocity limits you've set are extremely limiting. It'll be hard for the robot to follow any global path when its rotational velocity is limited to 0.07 radians/second and its translational velocity is limited to 0.07 meters/second. To make those limits work, I'd expect you'll have to play around a lot with the trajectory scoring parameters. Personally, I've never run navigation with such tight constraints.

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Originally posted by eitan with karma: 2743 on 2011-09-07

This answer was ACCEPTED on the original site

Post score: 0