SmartTemplate ROS2 Nodes

Virtual Template

To support this tutorial, we use a ROS2 node called virtual_template. It simulates the behavior of the SmartTemplate robot. It does not control real hardware, but instead emulates the robot’s motion logic based on simplified kinematics.

Robot model parsing: At startup, reads the robot’s URDF (robot_description) to load joint names, joint limits, and encoder-to-joint conversion ratios.
Kinematic model: defines simple forward kinematics (FK) and inverse kinematics (IK) for 3 prismatic joints (horizontal, vertical, and insertion).
Motion emulation: holds internal state for current and desired joint values. Moves the joints gradually toward the target position in small steps.
State publishers: Periodically publishes the simulated joint states and end-effector (needle tip) pose

Interfaces

The node is implemented in Python using rclpy and provides the following interfaces:

Published Topics:

Topic	Type	Description
/end_effector_pose	geometry_msgs/PoseStamped	Current needle tip pose in the world frame, computed via TF transform from needle_link
/joint_states	sensor_msgs/JointState	Current joint values (3 prismatic joints) in meters, as expected by standard ROS tools

Subscribed Topics:

Topic	Type	Description
/desired_position	geometry_msgs/PoseStamped	Target pose to align the robot tip to, typically in the world or scanner frame
/desired_command	std_msgs/String	Predefined motion commands: HOME, RETRACT, or ABORT

World Pose Listener

In addition, the smart_template_demo package includes the world_pose_listener node, which listens to the /world_pose topic. When a new pose is received, it triggers a TF static broadcast to update the base_link frame with respect to the world frame. This is crucial for maintaining the correct TF tree structure during simulated motion.

⬅️ Back to SmartTemplate Description Package

Next: Tutorial Steps ➡️

Back to Table of Contents ↩️