franka_selfcollision

This package contains the library and the node for self-collision checking of the FR3 Duo and Mobile FR3 Duo robots.

Important

Minimum necessary franka_description version is 2.3.2. You can clone franka_description package from https://github.com/frankarobotics/franka_description.

Functionality

This monitoring node is spawned by fr3_duo.launch.py or mobile_fr3_duo.launch.py in franka_bringup if the check_selfcollision argument is enabled.

The node continuously monitors the robot’s joint states to check for self-collisions between the robot links. It handles both fr3_duo and mobile_fr3_duo configurations. It performs two main actions upon detecting a collision (or violation of the security margin):

Publishes Status: Sends a boolean to the topic ~/<node_name>/collision_detected (where <node_name> is set via the name parameter in the launch file, default: self_collision_node). The topic uses best effort QoS (rclcpp::SensorDataQoS). Subscribers must use a compatible QoS profile (e.g. rclcpp::SensorDataQoS() in C++ or qos_profile_sensor_data in Python) to receive messages.
Logs Warning: Prints the specific colliding link pairs to the console if enabled (throttled to 1Hz to prevent spam).

Configuration

Parameters are defined in config/self_collision_node.yaml:

security_margin: Safety buffer around the robot links in meters (default: 0.045).
print_collisions: If true, logs the names of the colliding links to the console.
robot_description_semantic: SRDF XML used to exclude allowable collision pairs.

Usage

Both nodes are automatically started when the robot is launched with check_selfcollision set to true:

# FR3 Duo
ros2 launch franka_bringup fr3_duo.launch.py \
    check_selfcollision:=true

# Mobile FR3 Duo
ros2 launch franka_bringup mobile_fr3_duo.launch.py \
    check_selfcollision:=true