SmallBot is a simple 6WD robot simulation based on ROS and Gazebo and a real robot based on a 6WD chasis. The project is being developed and tested on ROS Melodic and Gazebo 9.0.0.

Robot movement and control simulation is based on Gazebo joint_state_publisher and DiffDrivePlugin6W plugins.

The real robot is being developed based on YFRobot 6WD chasis

The motors on the chasis were replaced with DFROBOT metal DC geared motor w/encoder

NVIDIA Jetson Nano board is used as central processing unit, Waveshare Uninterruptible Power Supply UPS Module for Jetson Nano is used to provide power to the robot.

Motors are controlled by 3 modified Waveshare Motor Driver HAT for Raspberry boards. The modification includes removing MP1584 regulator and connecting VIN and 5V lines on the module. As I use 5V supply from Jetson board for motors, this regulator is not needed (and it doesn't work with supply voltage <6V).

IMX219-83 Stereo Camera connected to Jetson board is used to provide binocular vision to the robot.

Slamtec RPLidar A1 is used for scanning surroundings and navigation.

Temporarily I had to switch the hardware platform to Raspberry PI as I was not able to reach needed performance on reading motor encoders through Jetson GPIO even after switching from python to c++. This is still a subject for investigation.

smallbot_base/ - base robot software, which intefaces controllers to hardware drivers
smallbot_control/ - robot control, based on diffdrive controller
smallbot_description/ - xacro/urdf robot model for RVIZ and Gazebo and rviz files for visualisations
smallbot_driver/ - ROS nodes to interface with SmallBot hardware (motors and motor encoders)
smallbot_gazebo/ - Gazebo robot simulation

Be sure you have ros-melodic-hector-gazebo package installed as SmallBot uses plugins from this package

sudo apt-get install ros-melodic-hector-gazebo

Checkout the repository into src directory of ros workspace

git clone https://github.com/belovictor/SmallBot.git

Build project

catkin_make

Run environment setup

. devel/setup.bash

roslaunch smallbot_description display_model.launch

First launch Gazebo simulation

roslaunch smallbot_gazebo smallbot_world.launch

Then start control

rqt

Open robot control plugin from menu - Plugins -> Robot tools -> Robot steering - and set topic to /cmd_vel
Change linear and angular velocity to make robot moving in Gazebo simulation

Lidar readings can be visualized in RVIZ

Launch all nodes on robot

roslaunch smallbot_description bringup.launch

Then launch RVIZ visualisation to monitor robot movements

roslaunch smallbot_description display_movement.launch

Finally to control robot movements

rqt

Open robot control plugin from menu - Plugins -> Robot tools -> Robot steering - and set topic to /smallbot_drive_controller/cmd_vel
Change linear and angular velocity to make robot moving in Gazebo simulation

The real robot is work in progress, I will publish 3D models of it's parts when the design is finished

First of all, much of the code in this project is based on Amperka Abot ROS robot and their series of posts on how to build your own robot with ROS

JetsonGPIO library is used to inteface with GPIO on Jetson Nano