easynav_simple_recovery

A simple recovery system for EasyNav, written to be read: a starting point for your own. Read SimpleRecoveryManager.cpp from top to bottom.

A recovery system is a RecoveryManagerBase plugin hosted by recovery_node. EasyNav calls:

• update_rt(), every RT cycle, after the controller and before publishing. Keep it fast. This one:
  • brakes dead before an obstacle right ahead (override_velocity(): highest priority, not smoothed);
  • executes the mitigation chosen by update() (command_velocity(): takes over the controller, smoothed). A proposal lasts one cycle, so it is commanded on every cycle.
• update(), every non-RT cycle. Diagnose and decide, most severe case first:

Supported ROS 2 Distributions

Distribution	Status
humble
jazzy
kilted
lyrical
rolling

Usage

The area checked ahead is the robot’s: its radius and height come from system_node.robot_geometry (robot_radius and max_obstacle_z here are deprecated).

recovery_node:
  ros__parameters:
    recovery_manager:
      plugin: easynav_simple_recovery/SimpleRecoveryManager
      stop_distance: 0.3          # [m] beyond the robot radius
      min_obstacle_z: 0.05        # [m]
      sensors_timeout: 5.0        # [s]
      max_position_variance: 1.0  # [m^2]
      relocalize_timeout: 20.0    # [s]
      rotate_speed: 0.5           # [rad/s]
      stuck_time: 10.0            # [s]
      stuck_distance: 0.05        # [m]
      backup_speed: 0.1           # [m/s]
      backup_time: 2.0            # [s]
      max_backup_attempts: 3
      slow_down_max_linear_vel: 0.1  # [m/s], 0: never slow down

Reconfiguring as a mitigation

request_reconfigure() changes parameters of any EasyNav node and reconfigures EasyNav to apply them, between cycles: the mission goes on, and the robot only stops during the transitions. The recovery system is reloaded too, so a new instance starts with fresh members: keep in NavState what you need to remember. EasyNav lists the parameters changed so far in reconfigured_parameters ("node/parameter"), and request_restore_parameters() restores them.

Changelog for package easynav_simple_recovery

0.5.0 (2026-10-08)

• First release: SimpleRecoveryManager
• Runtime reconfiguration (rejected ones are handled)
• Robot geometry from system_node
• Contributors: Francisco Martín Rico