ROS2 STorM32 Gimbal Driver

This is a ROS2 driver to communicate with STorM32 gimbal controllers. It is based on the original ROS1 based repository by McGill Robotics which can be found here. It was directly ported to ROS2, applying minor (convenience) changes and making it Python3 compatible.

You MUST configure your gimbal with the Windows app before using this package.

This package has been tested on ROS2 Foxy Fitzroy on Ubuntu 20.04. with Python3.8, but should generally work with any ROS2 distribution and modern Linux systems (including single board computers like the RaspberryPi or NVIDIA Jetson).

Setting up

Clone this repository into your colcon workspace's src folder:

git clone https://github.com/defrag-bambino/ros2-storm32-gimbal

Dependencies

Before proceeding, make sure to install all dependencies by running:

rosdep update
rosdep install --from-paths storm32_gimbal_* --ignore-src -y

and

pip3 install pyserial transforms3d numpy

Compiling

You must compile this package before being able to run it. You can do so by running (don't forget ro source your ros2 installation beforehand):

colcon build

from the root of your colcon workspace.

Running

Source the overlay workspace:

source install/setup.bash

To run, simply launch the storm32_controller_node node as such:

ros2 run storm32_gimbal_controller storm32_gimbal_controller 

You can change the port and TF frame ID by passing them as parameters

ros2 run storm32_gimbal_controller storm32_gimbal_controller --ros-args -p serial_port:=/dev/ttyACM0 -p frame_id:=example_frame

Interfacing

The gimbal_ref frame

All orientations used by this package are relative to a global reference frame called gimbal_ref. This reference frame is attached to the gimbal, and has a z axis always pointing away from the center of the earth (i.e. it does not pitch or roll, but can yaw).

Topics

This package publishes to two topics:

• ~camera_orientation: The IMU1 readings as a GimbalOrientation message (i.e. the orientation of the gimballed link relative to the global gimbal_ref frame). Since the link is stabilized, this should always be approximately the target orientation of the gimbal.
• ~controller_orientation: The IMU2 readings as a GimbalOrientation message (i.e. the orientation of the STorM32 board relative to the global gimbal_ref frame). This should represent the orientation of the gimbal and is not stabilized.

A GimbalOrientation message displays the orientation both as a quaternion and euler angles (yaw, pitch, roll - in degrees).

You can also set a new target orientation relative to the gimbal_ref frame by publishing a TargetGimbalOrientation message to the ~target_orientation topic. It's orientation field is of type GimbalOrientation and thus has a quaternion and also yaw, pitch, roll properties which are all expected to be relative to the gimbal_ref frame. Wether the gimbal driver will use the quaternion or euler angles is determined by the use_quaternion boolean. The unlimited field defines whether the controller should attempt to limit its rotation to hard set limits on the STorM32 controller.

Contributing

Contributions are welcome. Simply open an issue or pull request on the matter, and it will be accepted as long as it does not complicate the code base too much.

License

See LICENSE.