Some ROS2 with raspberry pico, nvidia Jetson AGX and other stuff

Introduction

This repository includes my first try to integrate raspberry pico as a motor driver and integrate with ROS2 in a basic setup for a 2WD/4WD autonomous car

Technologies

Hardware

• Raspberry pico (1)
• Motor Driver DRV8833 (1 or 2)
• DC Motors with hall encoder (2 or 4)
• Jetson Nano (1) or Jetson AGX (1)

Software

• C++
• Python 3.8.10
• Ubuntu 20.04
• ROS 2 Foxy
• Jetpack 5.0.1 Developer Preview
• VSC

Setup

This is only for checking motor integration. No encoder input at this time.

Program description

1. motor_driver

Objective

Test motor 2 motor movement, direction forward/reverse

Expected behaviour

while(1)
{
    Motor 1 move forward
    Motor 1 move backward
    Motor 1 stop

    Motor 2 move forward
    Motor 2 move backward
    Motor 2 stop
}

2. motor2_driver

Objective

Test motor speed control

Expected behaviour

while(1)
{
    Motor 1 move forward full speed
    Motor 2 move forward full speed

    Motor 2 move backward full speed
    Motor 2 move backward full speed

    Motor 2 move backward half speed
    Motor 2 move backward half speed
}

3. motor3_driver

Only some testing. Anything too much relevant.

4. motor4_ros

First testing of a node for raspberry pico for subscribe and publish data to/from motors using micro ROS The code uploaded into the raspberry pico creates some ROS2 objects:

subscriber /mobile_base_controller/cmd_vel (Type: geometry_msgs/msg/Twist)

publisher /pico_publisher (Type: std_msgs/msg/Int32)

Compile and copy the program into raspberry-pico:

cd build
make
cp motor4_ros.uf2 /media/administrator/RPI-RP2/

execute the following code into the master device that the raspberry pico is connected to on a terminal 1:

sudo docker run --device=/dev/ttyACM0:/dev/ttyACM0 -it --rm --net=host microros/micro-ros-agent:foxy serial --dev /dev/ttyACM0 baudrate=115200

you can test the connection using this command on a terminal 2 (linear x is the speed, angular z is the steering):

ros2  topic  pub --once /mobile_base_controller/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 80.0, y: 0.0, z: 0.0}, angular: {x: 1, y: 2.0, z: 1.8}}"

Status

At this state I'm testing raspberry pico before integrating as a ros2 node to move motors and collect telemetry

Me

I'm Juan Ramirez Jardua, electrical engineer. My main function is to implement and support GxP systems in the pharmaceutical industry, but in my free time I enjoy with robotics, photography, cats and other hobbies.

If you like photography as I do, you can visit me at @juanramirezj