Obstacle layer in global costmap not set

Question

Greeting,

I would like to ask about setting the global costmap parameters especially the plugins. Currently in my system I enabled the following plugins- static, inflation, obstacle and voxel layers. I am wondering that the obstacle layer did not work as expected.

In the pictures, you see that there is a cart in front of the robot that is detected by laser scanner as an obstacle. However, there is no black, inflated circle around it, so I assume it did not work.

Here is the parameters. Does anyone spot any mistake here?

  global_costmap:
    ros__parameters:
      footprint_padding: 0.03
      update_frequency: 4.0
      publish_frequency: 2.0
      global_frame: map
      robot_base_frame: robot_base_footprint
      use_sim_time: False
      robot_radius: 0.3 # radius set and used, so no footprint points
      resolution: 0.05
      plugins: ["static_layer", "inflation_layer", "obstacle_layer", "voxel_layer"]
      obstacle_layer:
        plugin: "nav2_costmap_2d::ObstacleLayer"
        enabled: True
        observation_sources: scan
        footprint_clearing_enabled: true
        max_obstacle_height: 2.0
        combination_method: 1
        scan:
          topic: /scan
          obstacle_max_range: 2.5
          obstacle_min_range: 0.0
          raytrace_max_range: 3.0
          raytrace_min_range: 0.0
          max_obstacle_height: 2.0
          min_obstacle_height: 0.0
          clearing: True
          marking: True
          data_type: "LaserScan"
          inf_is_valid: true
      voxel_layer:
        plugin: "nav2_costmap_2d::VoxelLayer"
        enabled: True
        footprint_clearing_enabled: true
        max_obstacle_height: 2.0
        publish_voxel_map: True
        origin_z: 0.0
        z_resolution: 0.05
        z_voxels: 16
        max_obstacle_height: 2.0
        unknown_threshold: 15
        mark_threshold: 0
        observation_sources: pointcloud
        combination_method: 1
        pointcloud:  # no frame set, uses frame from message
          topic: /intel_realsense_r200_depth/points
          max_obstacle_height: 2.0
          min_obstacle_height: 0.0
          obstacle_max_range: 2.5
          obstacle_min_range: 0.0
          raytrace_max_range: 3.0
          raytrace_min_range: 0.0
          clearing: True
          marking: True
          data_type: "PointCloud2"
      static_layer:
        plugin: "nav2_costmap_2d::StaticLayer"
        map_subscribe_transient_local: True
        enabled: True
        subscribe_to_updates: true
        transform_tolerance: 0.1
      inflation_layer:
        plugin: "nav2_costmap_2d::InflationLayer"
        enabled: True
        inflation_radius: 0.3
        cost_scaling_factor: 2.7
        inflate_unknown: false
        inflate_around_unknown: true
      always_send_full_costmap: True

Answer 1

Order of the plugins matters. I believe that to be the problem here. In your params you have

plugins: ["static_layer", "inflation_layer", "obstacle_layer", "voxel_layer"]

Which means that nav2 will first check static_layer, then run inflation on that, and after that run the costmap generation for obstacle_layer. In the Rviz screenshot there are small grey pixels under the laser scan markings which means the obstacle_layer is doing things.

To inflate the obstacle_layer detections (and voxel_layer which you might want to do as well) you have to move the inflation_layer to be the last plugin.

plugins: ["static_layer", "obstacle_layer", "voxel_layer", "inflation_layer"]