Processing Units

Our robot consists of components which are connected as shown in the block diagram below:

The Teensy 3.2 microcontroller board is connected to the encoder and optional IMU sensor as well as the motor driver actuator. It communicates to the Raspberry Pi 4 B via USB over the rosserial protocol. The motor driver and the optional IMU exchange data over I2C with the microcontroller. The RPLIDAR has a serial-to-USB converter and is therefore connected to one of the USB ports of the SBC. The motor encoder sensors are interfaced through the GPIO pins of the microcontroller. The following shows the connection diagram of the components:

Overview of ROS nodes and topics for the Remo robot

The following launch file will bring up the hardware nodes, load the robot description onto the parameter server, start diff_drive_controller, and begin to publish the transformations using tf. Run this launch file on the robot's SBC:

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roslaunch diffbot_bringup bringup.launch model:=remo

On the development PC, you can use the teleop node to steer the robot. To do this, run the following:

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roslaunch diffbot_bringup keyboard_teleop.launch

Issuing the rosnode list command shows the following list of started nodes:

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/diffbot/controller_spawner
/diffbot/diffbot_base
/diffbot/robot_state_publisher
/diffbot/rosserial_base_controller
/diffbot_teleop_keyboard
/rosout