Navigating with SimpleStack and EasyNav

This HowTo explains how to perform navigation using the Simple Stack in EasyNavigation (EasyNav). The Simple Stack operates on a binary occupancy map, ideal for lightweight simulations or quick prototyping.

Overview

This tutorial assumes you already have a map created with SLAM Toolbox or another mapping method. If you have not yet generated a map, follow Mapping with SLAM Toolbox and EasyNav first.

Once you have your map, save the .yaml and image file (.pgm/.png) in any package within your workspace, such as easynav_indoor_testcase/maps. You will later reference it using the parameters package and map_path_file. (Alternatively, you can use an absolute path with map_path_file alone.)

—

Creating a Parameter File

In this example we will use:

• The SeReST controller for trajectory tracking.

• The AMCL localizer for probabilistic localization.

• The Simple Maps Manager to load the occupancy map.

Below is a minimal working configuration for navigation with the Simple Stack.

controller_node:
  ros__parameters:
    use_sim_time: true
    controller_types: [serest]
    serest:
      rt_freq: 30.0
      plugin: easynav_serest_controller/SerestController
      allow_reverse: true
      max_linear_speed: 0.8
      max_angular_speed: 1.2
      v_progress_min: 0.08
      k_s_share_max: 0.5
      k_theta: 2.5
      k_y: 1.5
      goal_pos_tol: 0.1
      goal_yaw_tol_deg: 6.0
      slow_radius: 0.80
      slow_min_speed: 0.02
      final_align_k: 2.5
      final_align_wmax: 0.8
      corner_guard_enable: true
      corner_gain_ey: 1.8
      corner_gain_eth: 0.7
      corner_gain_kappa: 0.4
      corner_min_alpha: 0.35
      corner_boost_omega: 1.0
      a_lat_soft: 0.9
      apex_ey_des: 0.05

localizer_node:
  ros__parameters:
    use_sim_time: true
    localizer_types: [simple]
    simple:
      rt_freq: 50.0
      freq: 5.0
      reseed_freq: 1.0
      plugin: easynav_simple_localizer/AMCLLocalizer
      num_particles: 100
      noise_translation: 0.05
      noise_rotation: 0.1
      noise_translation_to_rotation: 0.1
      initial_pose:
        x: 0.0
        y: 0.0
        yaw: 0.0
        std_dev_xy: 0.1
        std_dev_yaw: 0.01

maps_manager_node:
  ros__parameters:
    use_sim_time: true
    map_types: [simple]
    simple:
      freq: 10.0
      plugin: easynav_simple_maps_manager/SimpleMapsManager
      package: easynav_indoor_testcase
      map_path_file: maps/home.yaml

planner_node:
  ros__parameters:
    use_sim_time: true
    planner_types: [simple]
    simple:
      freq: 0.5
      plugin: easynav_simple_planner/SimplePlanner
      robot_radius: 0.25

sensors_node:
  ros__parameters:
    use_sim_time: true
    forget_time: 0.5
    sensors: [laser1]
    perception_default_frame: odom
    laser1:
      topic: scan_raw
      type: sensor_msgs/msg/LaserScan
      group: points

system_node:
  ros__parameters:
    use_sim_time: true
    position_tolerance: 0.3
    angle_tolerance: 0.15

—

Running the Simulation

1. Launch the simulator You can disable the GUI to save computational resources:

   ros2 launch easynav_playground_kobuki playground_kobuki.launch.py gui:=false
   

2. Open RViz2 in a new terminal:

   ros2 run rviz2 rviz2 --ros-args -p use_sim_time:=true
   

3. Start EasyNav with your parameter file:

   ros2 run easynav_system system_main \
      --ros-args --params-file ~/easynav_ws/src/easynav_indoor_testcase/robots_params/simple.serest_params.yaml
   

   (You can also create a launcher for convenience.)

4. Send navigation goals In RViz2, use the “2D Goal Pose” tool to send target positions. The robot will autonomously plan and navigate toward them.

—

Notes

• The Simple Stack uses a binary map: cells are free or occupied (no graded cost).

• For smoother paths or cost-aware planning, use the Costmap Stack (Mapping with the Costmap Stack).

• Verify that map_path_file and package point to the correct files.

• You can tune controller parameters (k_theta, k_y, etc.) and speed limits for better performance.