some ROS drivers for the Beaglbone Blue

WIP!!! Ugly code included!!!

The drivers use the librobotcontrol library by StrawsonDesign

Nodes overview

• differential driver node using the onboard motor ports
• publisher for IMU messages from MPU9250
• publisher for battery state

• Installation
• Usage
  • Differential motor driver
    • Parameter
    • Run
  • Battery state node
    • Parameter
    • Run
  • IMU node
    • Run
    • Visualizing IMU with rviz
    • optional IMU tools
• Contributing
• Credits

TODO

and default values

• ~left_motor = 1
• ~right_motor = 2
• ~timeout = 5
• ~maxspeed = 0.4
• ~minspeed = 0.1
• ~wheelbase = 0.2
• ~turnspeed = 1
• ~duty_factor = 1 - velocity to PWM duty cycle factor (simple linear approach)

rosrun bbblue_drivers diff_motor_driver

rosrun bbblue_drivers diff_motor_driver _left_motor:=3 _right_motor:=4 _minspeed:=0.137 _maxspeed:=0.364 _duty_factor:=2.2

Publish to cmd_vel manually

`rostopic pub -1 /cmd_vel geometry_msgs/Twist -- '[1.0, 0.0, 0.0]' '[0.0, 0.0, 0]'``

and default values

• ~power_supply_technology = 3
• ~min_cell_voltage = 3.3 ( 0% )
• ~max_cell_voltage = 4.15 ( 100% )

rosrun bbblue_drivers battery_state

and default values

• ~frame_id = imu_link
• ~linear_acceleration_stddev = 0.04
• ~angular_velocity_stddev = 0.02
• ~orientation_stddev = 0.0025
• ~magnetometer_stddev = 0.04

covariances used from razor_imu_9dof https://github.com/KristofRobot/razor_imu_9dof/blob/indigo-devel/nodes/imu_node.py

Start the IMU node

rosrun bbblue_drivers imu_pub_node

A static transformation is required:

rosrun tf static_transform_publisher 0.0 0.0 0.0 0 0 0 map imu_link 10

The Beaglebone Blue has no display port. So for visualization an aditional system is required.

export ROS_MASTER_URI=http://rosbot:11311

Starting rviz after exporting the MASTER usxbrix

rviz

red - x green - y blue -z

sudo apt-get install ros-melodic-imu-tools

rosrun imu_filter_madgwick imu_filter_node

Pull requests and issues are welcome.

librobotcontrol