Let’s make a mini SLAM robot using 4WD robot kit and small Lidar

Overview

The idea is to build a mini SLAM robot, using a 4WD robot kit that can be improved using additional sensors for SLAM.

Background

I wanted to try a SLAM robot. As I didn’t have any hands-on experience on working on SLAM robots, I think I could try it by building the robot myself.

I searched and found a good 4WD robot kit that already includes several basic components like motor drivers, includes additional components like a camera, and is compatible with Raspberry Pi. I thought this was a good start, since I don’t need to think about the motor-control components.

Then, the idea was simply attaching a small Lidar on top of this 4WD robot, and adding the required Raspberry Pi.

YDLIDAR X2L, Raspberry Pi 4B, Adeept AWR 4D robot kit

Additionally, I also added an MPU6050 as the IMU sensor for future use.

Components

Part Product name Price Remarks
Robot Kit Adeept AWR 4D Robot Kit ￥7552 store
amazon.jp
Small Lidar YDLIDAR X2L ￥7975 website (Not X2L, but X2)
amazon.jp
Raspberry Pi Raspberry Pi 4B 8GB ￥9400 amazon.jp
SD Card Micro SD 32GB Class 10 UHS-3 ￥600  
IMU MPU6050 ￥280  

Adeept AWR 4D Robot Kit

YDLIDAR

How to use

1. SDK Installation

  1. Clone https://github.com/YDLIDAR/sdk/tree/X2L
  2. Git checkout master (master is OK)
  3. Build by following the readme
    Notes: need to mkdir build first.
  4. Test the build
    1. sudo ./ydlidar_test
    2. Input for X2L: 0, yes, no

Notes:

  • The above run with sudo, since communication with /dev/ttyUSB0 need permissions
  • On Raspberry Pi, it is not a problem because the lidar will be mounted on /dev/ydlidar
  • On Ubuntu (desktop), it will be on /dev/ttyUSB0
    • Problem: need to do sudo chmod 666 on every replug

2. ROS Driver Installation

  1. Create ws for test if needed
  2. On src directory, clone: https://github.com/YDLIDAR/ydlidar_ros
    Note: master branch is OK
  3. Need to create the /dev/ydlidar device using the shell script
    1. sudo chmod 777 ydlidar_ros/startup/*
    2. sudo sh ydlidar_ros/startup/initenv.sh
  4. Unplug and re-plug.
  5. Confirm by executing:
    ls /dev

Building map from Lidar data

Hector SLAM

http://wiki.ros.org/hector_slam

References

Similar articles:

Datasheets: