cartesian-controllers

Cartesian Controller Server that combines ROS2 and YARP for generic system teleoperation.

This project integrates YARP and ROS 2 to provide a Cartesian control server for robots. It enables communication with a YARP subdevide through its ICartesianControl interface, while allowing the robot's current position to be published and commands to be received via ROS 2 nodes.

Overview

The CartesianControlServerROS2 package is part of the cartesian-controllers repository. It acts as a bridge between YARP and ROS 2, providing real-time control and feedback for robotic systems. The server allows for the manipulation of the robot’s position, velocity, and force/torque, as well as gripper control.

Key Features

• Direct control via YARP's ICartesianControl interface.
• ROS 2 integration for publishing robot states and receiving commands from ROS 2 nodes.
• Supports position, velocity, force/torque, and gripper control via dedicated callbacks.
• Fully configurable parameters such as command types and reference frames (base or TCP).

Installation

Clone the repository and install the necessary dependencies:

~$ git clone https://github.com/mercerebo1/cartesian-controllers.git
~$ cd cartesian-controllers

Ensure both YARP and ROS 2 are correctly installed and configured on your system.

Usage example

This Cartesian Control Server was initially created to use BasicCartesianControl as a YARP subdevice from kinematics-dynamics. Please, see below proposed control arquitecture:

• Block 1: /spacenav node from spacenav package which sends buttons state and linear and angular component of a SpaceMouse.

• Block 2: /spacenav_device node from spacenav_device package that manage analogic data received and proccess data according three control modes: Twist (command velocities to TCP), Pose (command positions to TCP) and Wrench (command forces to TCP).

• Block 3: Current Cartesian Control Server ROS 2 which is able to communicate to other ROS 2 nodes and wrap a YARP subdevice (BasicCartesianControl).

• Block 4: Joint control from cartesian control applying Inverse Kinematics solver 'Screw Theory' from kinematics-dynamics.

• Block 5: Actuation control accessed by Motor Control Interfaces differentiating between simulated and real environment.

This control arquitecture is a modification from the arquitecture presented in “A generic controller for teleoperation on robotic manipulators using low-cost devices,” [1]. The aim is to start a transition from YARP to ROS 2.

References

[1] B. Łukawski, J. G. Victores, and C. Balaguer, “A generic controller for teleoperation on robotic manipulators using low-cost devices,” in XLIV Jornadas de Automática, 2023, pp. 785-788. [Online]. Available: https://doi.org/10.17979/spudc.9788497498609.785.

Available Callbacks:

The server handles multiple types of commands through ROS 2 topics:

• poseTopic_callback: Processes Pose messages to send position commands to the controller.
• twistTopic_callback: Processes Twist messages to control the robot's velocity.
• wrenchTopic_callback: Processes Wrench messages to send force/torque commands.
• gripperTopic_callback: Controls the robot’s gripper actuator (open, close, stop).

Parameter Configuration:

The server allows the configuration of several parameters, including:

• Transmission command type: Define the type of control commands (position, velocity, force).
• Reference frame: Select between base or TCP frame for executing commands.

Code Structure

CartesianControlServerROS2.cpp

This file implements the main server logic for handling Cartesian control:

• Subscription Callbacks: Manages incoming messages to control the robot’s position, velocity, force, and gripper.
• Parameter Management: Dynamically adjusts the server's settings based on incoming messages to ensure correct robot control.

DeviceDriverImpl.cpp

This file handles device-level control, including:

• Initialization and Configuration: Opens the Cartesian control device, sets execution parameters, and initializes the ROS 2 node.
• Publications and Subscriptions: Sends PoseStamped messages and listens for Pose, Twist, Wrench, and Int32 messages for gripper control.
• Robot Control: Defines callbacks for processing commands and sending them to the controller.

PeriodicThreadImpl.cpp

This file implements the run function, which updates the robot's state periodically:

• State Retrieval: Captures the current position and status of the robot.
• Time Conversion: Converts timestamps for ROS 2 message compatibility.
• Orientation Calculation: Computes robot orientation using the KDL library.
• Message Publication: Sends PoseStamped messages with updated robot state to the ROS 2 topic.

Contributing

Feel free to submit issues or pull requests to improve the project. Contributions are welcome!