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.

Setup

Complete the installation steps in Build & Install first (any of APT, Pixi or source). This tutorial’s example configuration uses the SeReST Controller, Simple Localizer, Simple Maps Manager and Simple Planner plugins, which the core easynav package does not include:

• APT:

  sudo apt install \
    ros-<distro>-easynav-serest-controller \
    ros-<distro>-easynav-simple-localizer \
    ros-<distro>-easynav-simple-maps-manager \
    ros-<distro>-easynav-simple-planner
  

• Pixi:

  pixi add \
    ros-<distro>-easynav-serest-controller \
    ros-<distro>-easynav-simple-localizer \
    ros-<distro>-easynav-simple-maps-manager \
    ros-<distro>-easynav-simple-planner
  

• Source: already built if you cloned easynav_plugins as described in Build from source.

You will also need the simulator and example config, which are only distributed as source — clone them into ~/easynav_ws/src regardless of install method:

cd ~/easynav_ws/src
git clone https://github.com/EasyNavigation/easynav_playground_kobuki.git
git clone https://github.com/EasyNavigation/easynav_indoor_testcase.git

Build and source the workspace as described in Build and source the workspace.

Once you have your map, save the resulting .map file (the Simple Maps Manager’s own text format, produced by its savemap service) 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.map

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]
    laser1:
      topic: scan_raw
      type: sensor_msgs/msg/LaserScan

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.