uavcan_ros_bridge¶

Bridge for communication between ROS and the uavcan CAN-bus protocol

Dependencies & building¶

After cloning, execute the following command in the cloned repo:

git submodule update --init --recursive

Once done, go into the folder libuavcan/libuavcan/dsdl_compiler/pyuavcan/ and execute:

sudo python setup.py install

Then, simply put this project into a catkin workspace and run catkin_make or catkin build to build everything.

Usage¶

Launch conversion in both directions (between uavcan and ros) by running the launch file:

roslaunch uavcan_ros_bridge bridge.launch

This will launch two nodes: the uavcan_to_ros_bridge_node and the ros_to_uavcan_bridge_node which handle the conversion in the respective directions. Any new type conversions should be added to the node that handles the relevant direction.

Adding new conversions¶

You can add new conversion headers for ros to uavcan and uavcan to ros with corresponding implementations in the src folder. An example implementation for an IMU might look like this:

template <>
bool convert(const uavcan::equipment::ahrs::RawIMU& uav_msg, sensor_msgs::Imu& ros_msg)
{
    ros_msg.header.stamp = convert_timestamp(uav_msg.timestamp);
    ros_msg.linear_acceleration.x = uav_msg.accelerometer_latest[0];
    ros_msg.linear_acceleration.y = uav_msg.accelerometer_latest[1];
    ros_msg.linear_acceleration.z = uav_msg.accelerometer_latest[2];
    ros_msg.angular_velocity.x = uav_msg.rate_gyro_latest[0];
    ros_msg.angular_velocity.y = uav_msg.rate_gyro_latest[1];
    ros_msg.angular_velocity.z = uav_msg.rate_gyro_latest[2];
    return true;
}

You then need to add them to the build configuration in the cmake file like this and link them into one of the bridges (the publisher or the subscriber) like this. Finally add them to either of the bridge nodes uavcan_to_ros_bridge or ros_to_uavcan_bridge similar to the already existing conversions, i.e. like:

ros_to_uav::ConversionServer<uavcan::equipment::actuator::ArrayCommand, std_msgs::Float32> server(uav_node, ros_node, "uavcan_command");

or

uav_to_ros::ConversionServer<uavcan::equipment::ahrs::RawIMU, sensor_msgs::Imu> server(uav_node, ros_node, "uavcan_imu");

where uavcan_command and uavcan_imu are the ros topics being subscribed to and published to respectively.

Existing conversions (work in progress)¶

ROS to UAVCAN¶

std_msgs/Float32 to uavcan.equipment.actuator.ArrayCommand on ros topic /uavcan_command
sam_msgs/ArrayCommand to uavcan.equipment.actuator.ArrayCommand on ros topic /uavcan_array_command
std_msgs/Int32 to uavcan.equipment.esc.RPMCommand on ros topic /ros_to_uavcan_bridge_node/rpm_command

UAVCAN to ROS¶

uavcan.equipment.ahrs.RawIMU to sensor_msgs/Imu on ros topic /uavcan_imu
uavcan.equipment.gnss.Fix to sensor_msgs/NavSatFix on ros topic /uavcan_to_ros_bridge_node/gps_fix
uavcan.equipment.power.BatteryInfo to sensor_msgs/BatteryState on ros topic /uavcan_to_ros_bridge_node/battery_state
uavcan.equipment.ahrs.MagneticFieldStrength to sensor_msgs/MagneticField on ros topic /uavcan_to_ros_bridge_node/magnetic_field