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robco_hardware

Legacy documentation

This section documents the robco_ros2 integration as shipped with RobFlow 7.x. It has not been updated for RobFlow 8, and the interface is not available in current systems.

The robco_hardware package provides a ros2_control hardware interface for RobCo Robots.

note

The ROS 2 interface is currently not shipped by default on RobCo Robots. If you are interested in using the ROS 2 interface on your RobCo Robot, please get in touch with RobCo support.

RobCo ros2_control interface overview

Using the hardware interface​

The ROS interface is disabled when the Robot Control Unit starts up and has to be enabled using the RobFlow API before using the hardware interface. This can be done in a browser and is described in Using the hardware interface.

By default, the hardware interface expects to communicate with the ROS bridge running on the controller via topics robco_joint_states and robco_joint_commands. These topic names can be configured via the optional parameters joint_states_topic and joint_commands_topic to the <hardware> XML tag of the URDF, as demonstrated in Assembling the URDF file.

Provided command interfaces​

The hardware interface exposes the following types of command interfaces:

  • position + velocity + acceleration (must all be active at the same time)
  • effort (joint torque)
note

At any given point in time, the same set of command interfaces must be active on all Robot joints. In other words, one joint cannot use a different set of command interfaces than another.

Joint position/velocity/acceleration interface​

When the position, velocity and acceleration interfaces are active, the internal controller operates in trajectory streaming mode. The internal desired values for joint position, velocity and acceleration are immediately updated from the values coming from ros2_control.

Joint effort (torque) interface​

When only the effort interface is activated, the internal controller operates in torque streaming mode. In this mode, the controller compensates gravity (τg) and coriolis forces (τcoriolis) only. The effort command (τROS) is then added to form the final torque vector commanded to the motors:

τmotor = τROS + τg + τcoriolis