Loopback Simulator

Source code on Github.

The nav2_loopback_sim is a stand-alone simulator to create a “loopback” for non-physical simulation to replace robot hardware, physics simulators (Gazebo, Bullet, Isaac Sim, etc). It computes the robot’s odometry based on the command velocity’s output request to create a perfect ‘frictionless plane’-style simulation for unit testing, system testing, R&D on higher level systems, testing behaviors without concerning yourself with localization accuracy or system dynamics, and multirobot simulations.

Parameters

update_duration

Type	Default
double	0.01

Description: The duration between updates (s)

base_frame_id

Type	Default
string	“base_link”

Description: The base frame to use.

odom_frame_id

Type	Default
string	“odom”

Description: The odom frame to use.

map_frame_id

Type	Default
string	“map”

Description: The map frame to use.

scan_frame_id

Type	Default
string	“base_scan”

Description: The scan frame to use to publish a scan

enable_stamped_cmd_vel

Type	Default
string	True

Description: Whether cmd_vel is stamped or unstamped (i.e. Twist or TwistStamped). Note: This parameter is default false in Jazzy or older! Kilted or newer uses TwistStamped by default.

scan_publish_dur

Type	Default
string	0.1

Description: The duration between publishing scan (in sec)

publish_map_odom_tf

Type	Default
string	true

Description: Whether or not to publish tf from map_frame_id to odom_frame_id

publish_clock

Type	Default
string	true

Description: Whether or not to publish simulated clock to /clock

Example

loopback_simulator:
  ros__parameters:
    base_frame_id: "base_footprint"
    odom_frame_id: "odom"
    map_frame_id: "map"
    scan_frame_id: "base_scan"  # tb4_loopback_simulator.launch.py remaps to 'rplidar_link'
    update_duration: 0.02