Getting started with the robot_navigation stack

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It's a shame that there's so little documentation for the robot_navigation stack because it's a great implementation of the navigation stack. The code is written cleanly, it has meaningful comments and can be easily extended with personal modifications.

After spending a few months diving into the code and intricacies of locomotor, dwb_local_planner and dwb_critics and painfully extracting config options, I came up with a navigation stack that works fairly well for my robot.

For everyone interested, here's the launch file I'm using:

<launch>
  <arg name="prefix" default="" />
  <node name="locomotor" pkg="locomotor" type="locomotor1" output="screen" launch-prefix="$(arg prefix)">
    <rosparam file="$(find locomotor)/launch/rovy.yaml" command="load"/>
  </node>
</launch>

And for config options (this is a very explicit version, I'm sure much can be optimized):

controller_frequency: 10.0
global_plan_topic: global_plan
global_plan_type: Path3D
global_plan_epsilon: -1.0
twist_topic: cmd_vel
twist_type: Twist3D

global_costmap:
  global_frame: map
  robot_base_frame: base_link
  rolling_window: false
  track_unknown_space: true
  always_send_full_costmap: false
  footprint_topic: "footprint"
  width: 15
  height: 15
  origin_x: -7.5
  origin_y: -7.5
  resolution: 0.07
  update_frequency: 2.0
  publish_frequency: 2.0

  footprint: [[0.11,0.15],[0.11,-0.15],[-0.27,-0.15],[-0.27,0.15]]
  footprint_padding: 0.02

  static_layer:
    map_topic: map
    first_map_only: true
    subscribe_to_updates: false
    use_maximum: false
    lethal_cost_threshold: 100
    unknown_cost_value: -1
    trinary_costmap: true

  obstacle_layer:
    transform_tolerance: 0.2
    observation_sources: scan_sensor
    scan_sensor: {
      topic: scan,
      sensor_frame: d435_link,
      observation_persistence: 0.0,
      expected_update_rate: 0.0,
      data_type: LaserScan,
      min_obstacle_height: -10.0,
      max_obstacle_height: 10.0,
      inf_is_valid: true,
      clearing: true,
      marking: true
    }
    obstacle_range: 1.5
    raytrace_range: 2.0

  inflation_layer:
    cost_scaling_factor: 15.0
    inflation_radius: 2.0
    inflate_unknown: false

  plugins:
   - {name: static_layer, type: "costmap_2d::StaticLayer"}
   - {name: obstacle_layer, type: "costmap_2d::ObstacleLayer"}
   - {name: inflation_layer, type: "costmap_2d::InflationLayer"}

local_costmap:
  global_frame: map
  robot_base_frame: base_link
  track_unknown_space: false
  always_send_full_costmap: true
  footprint_topic: "footprint"
  width: 3
  height: 3
  origin_x: -1.5
  origin_y: -1.5
  resolution: 0.02
  update_frequency: 10.0
  publish_frequency: 10.0
  rolling_window: true

  footprint: [[0.11,0.15],[0.11,-0.15],[-0.27,-0.15],[-0.27,0.15]]
  footprint_padding: 0.02

  obstacle_layer:
    transform_tolerance: 0.2
    observation_sources: scan_sensor
    scan_sensor: {
      topic: scan,
      sensor_frame: d435_link,
      observation_persistence: 0.0,
      expected_update_rate: 0.0,
      data_type: LaserScan,
      min_obstacle_height: -10.0,
      max_obstacle_height: 10.0,
      inf_is_valid: false,
      clearing: true,
      marking: true
    }
    obstacle_range: 1.5
    raytrace_range: 2.0

  inflation_layer:
    cost_scaling_factor: 15.0
    inflation_radius: 2.0
    inflate_unknown: false

  plugins:
   - {name: obstacle_layer, type: "costmap_2d::ObstacleLayer"}
   - {name: inflation_layer, type: "costmap_2d::InflationLayer"}

DluxGlobalPlanner:
  neutral_cost: 50
  scale: 3.0
  unknown_interpretation: lethal
  path_caching: false
  improvement_threshold: -1.0
  publish_potential: false
  print_statistics: false
  potential_calculator: dlux_plugins::AStar
  traceback: dlux_plugins::GradientPath

  # AStar
  manhattan_heuristic: false
  use_kernel: true
  minimum_requeue_change: 1.0

  # GradientPath
  step_size: 0.5
  lethal_cost: 250.0
  iteration_factor: 4.0
  grid_step_near_high: false

DWBLocalPlanner:
  update_costmap_before_planning: true
  prune_plan: true
  prune_distance: 1.0
  short_circuit_trajectory_evaluation: true
  debug_trajectory_details: false
#  publish_cost_grid_pc: true

  trajectory_generator_name: dwb_plugins::LimitedAccelGenerator
  # velocities
  min_vel_x: -0.4
  max_vel_x: 0.4
  min_vel_y: 0.0
  max_vel_y: 0.0
  max_vel_theta: 2.0
  # acceleration
  acc_lim_x: 1.2
  acc_lim_y: 0.0
  acc_lim_theta: 8.731380878
  # deceleration
  decel_lim_x: -1.2
  decel_lim_y: 0.0
  decel_lim_theta: -10.948097518
  # absolute speeds (in either direction)
  min_speed_xy: 0.1
  max_speed_xy: 0.4
  min_speed_theta: 0.3

  goal_checker_name ...