You're reading from Learn Robotics Programming - Second Edition

Product type Book

Published in Feb 2021

Publisher Packt

ISBN-13 9781839218804

Pages 602 pages

Edition 2nd Edition

Languages

Concepts

Robotics

Author (1):

Danny Staple

Table of Contents (25) Chapters

Preface

1. Section 1: The Basics – Preparing for Robotics

2. Chapter 1: Introduction to Robotics

3. Chapter 2: Exploring Robot Building Blocks – Code and Electronics

4. Chapter 3: Exploring the Raspberry Pi

5. Chapter 4: Preparing a Headless Raspberry Pi for a Robot

6. Chapter 5: Backing Up the Code with Git and SD Card Copies

7. Section 2: Building an Autonomous Robot – Connecting Sensors and Motors to a Raspberry Pi

8. Chapter 6: Building Robot Basics – Wheels, Power, and Wiring

9. Chapter 7: Drive and Turn – Moving Motors with Python

10. Chapter 8: Programming Distance Sensors with Python

11. Chapter 9: Programming RGB Strips in Python

12. Chapter 10: Using Python to Control Servo Motors

13. Chapter 11: Programming Encoders with Python

14. Chapter 12: IMU Programming with Python

15. Section 3: Hearing and Seeing – Giving a Robot Intelligent Sensors

16. Chapter 13: Robot Vision – Using a Pi Camera and OpenCV

17. Chapter 14: Line-Following with a Camera in Python

18. Chapter 15: Voice Communication with a Robot Using Mycroft

19. Chapter 16: Diving Deeper with the IMU

20. Chapter 17: Controlling the Robot with a Phone and Python

21. Section 4: Taking Robotics Further

22. Chapter 18: Taking Your Robot Programming Skills Further

23. Chapter 19: Planning Your Next Robot Project – Putting It All Together

24. Other Books You May Enjoy

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Driving in a straight line

By now, you have seen differences in the outputs – that is, a veer. In only 400 mm, my left side is around 20 mm behind the right, an error that is climbing. Depending on your motors, your robot may have some veer too. It is rare for a robot to have driven perfectly straight. We use the sensors to correct this.

Tip

This behavior works better on wooden flooring or MDF boards, and poorly on carpet.

This correction is still dead reckoning; slipping on surfaces or incorrect measurements can still set this off course. How can we use motors and encoders to correct our course and drive in a straight line?

Correcting veer with a PID

A behavior to self-correct steering and drive in a straight line needs to vary motor speeds until the wheels have turned the same amount. If the wheels turn the same amount soon enough, then they will account for major course deviations.

Our robot will use the encoder sensor to measure how much each wheel has...