stack.md

Intro to LinoRobot

Intro

Examine Linorobot again. You will see very detailed instructions for building a robot, both the hardware and the software. In our world, bullet, platform, cat are all fully compliant Linorobot robots.

Base hardware stack

• For the SBC we use either a Rasperry Pi 3B+ or a Raspberry Pi 4

  • Lidar is connected via USB to the Raspberry Pi

  • The Microcontroller is connected via USB to the Raspberry Pi

• For the microcontroller we use either a Teensy 3.2 or a Teensy 4.x (check this)

  • The motor controller is connected to the Teensy via

  • The IMU is connected to the Teensy via I2C bus

SBC Software

The SBC is running Ubuntu 20.04 and ROS 1.0. It is a standard install which we get from the Linorobot installation. Of course our own ROS code and scripts are then added to it. Certain standard Linorobot Nodes are launched.

Standard Linorobot Nodes

Microcontroller Software

The Teensy code is provided by Linorobot. We have tweaked it in small ways. See How To for information on rebuilding it and installing the software. This software has the following jobs:

1. Read the encoders to determine the apparent speed and direction of the robot

2. Subscribe to cmd_vel to determine the desired speed and direction

3. Use a PID controller to drive the motors to meet the desired speed and direction

4. Publish the actual speed and direction as computed by the encoders as ODOM_RAW

5. Read the IMU data (via the I2C bus) and publish it as IMU_RAW

6. Read other I2C sensors and actuators (coming soon!)