Wheeled Mobile Robotics

From Fundamentals Towards Autonomous Systems

Gregor Klancar,Andrej Zdesar,Saso Blazic,Igor Skrjanc

• Éditeur: Butterworth-Heinemann
• Année: 2017
• ISBN:
  9780128042380
• Sujet: Technology & Engineering
• Sous-sujet: Robotics

Wheeled Mobile Robotics: From Fundamentals Towards Autonomous Systems covers the main topics from the wide area of mobile robotics, explaining all applied theory and application. The book gives the reader a good foundation, enabling them to continue to more advanced topics. Several examples are included for better understanding, many of them accompanied by short MATLAB® script code making it easy to reuse in practical work. The book includes several examples of discussed methods and projects for wheeled mobile robots and some advanced methods for their control and localization.

It is an ideal resource for those seeking an understanding of robotics, mechanics, and control, and for engineers and researchers in industrial and other specialized research institutions in the field of wheeled mobile robotics. Beginners with basic math knowledge will benefit from the examples, and engineers with an understanding of basic system theory and control will find it easy to follow the more demanding fundamental parts and advanced methods explained.

• Offers comprehensive coverage of the essentials of the field that are suitable for both academics and practitioners
• Includes several examples of the application of algorithms in simulations and real laboratory projects
• Presents foundation in mobile robotics theory before continuing with more advanced topics
• Self-sufficient to beginner readers, covering all important topics in the mobile robotics field
• Contains specific topics on modeling, control, sensing, path planning, localization, design architectures, and multi-agent systems

Chapter 1

Introduction to Mobile Robotics

Abstract

This is an introductory chapter that presents the field of wheeled mobile robotics. Initially the words “robot,” “mobile,” and “wheel” that appear in the title of the book are explained. Then a brief classification of autonomous mobile systems is presented and an overview of various levels of autonomy is discussed. A short review of applications is followed by a list of important historical milestones that influenced the development of autonomous wheeled mobile robots.

Keywords

Robots; Mobile systems; Wheels; Autonomous systems; History

1.1 Introduction

1.1.1 Robots

The word robot has roots in Slavic languages. The meaning of “robota” in Polish is work or labor, while the word is more archaic in Czech or Slovenian language and means statute labor or corvée. The famous Czech writer Karel Čapek coined the word robot and used it in the science fiction play R.U.R., which stands for Rossum’s Universal Robots. The robots in the play are a sort of artificial human; in modern terminology cyborgs or androids would be more appropriate. The play witnessed huge success and the word robot was adopted by the majority of world languages. While the word robot is not even 100 years old, the idea of mechanic creatures goes very deep into history.

In Greek mythology we find many creatures that are used for particular tasks. Spartoi are mythical, fierce, and armed men who sprang up from the dragon’s teeth sown by Cadmus. They assisted Cadmus in building the Cadmeia or citadel of Thebes. Talos, created by Hephaestus, was a giant automaton made of bronze to protect Europa in Crete from pirates and invaders. The Greek god of blacksmiths and craftsmen, Hephaestus, is also credited for some other mechanical structures. Automata can be also found in ancient Jewish, Chinese, and Indian legends. The idea of mechanical automata that resembled either humans or animals was then present in literature throughout the history. It really became popular in the 19th century and, especially, the 20th century. In the 20th century robots found a new popular media to depict them and bring them to life: film. Some of the ideas in literature and films were attributed as science fiction at the time of creation, and later this fiction became a reality.

The robotic designs were not present only in fiction. Very early inventors tried to construct mechanical automata. The Greek mathematician Archytas is believed to have designed and built the first artificial, self-propelled flying device in the 4th century BC. A mechanical bird propelled by steam was said to have actually flown some 200 m. In the comprehensive heritage of Leonardo da Vinci several mechanical designs can be found. Among the rough sketches scattered throughout Leonardo’s notes, Rosheim [1] has reconstructed a programmable cart (Fig. 1.1) used as a base for Leonardo’s inventions, such as a robot lion and a robot knight. The spring of industrial revolution technological advancement resulted in the outburst of automation that gradually led to the mobile robotics we know today.

Fig. 1.1 Model of a bicycle and a programmable cart built based on Leonardo da Vinci’s notes.

1.1.2 Mobile

The word mobile has its roots in the Latin word of the same meaning, “mōbilis.” The majority of animal species possess the ability of locomotion. While some animals use passive systems to do so (they can move with water or air motion), others have developed more or less sophisticated mechanisms for active movement. Some animals perform locomotion in the 3D space (swimming in the water, flying in the air, moving through the soil), and others more or less follow the 2D surface of the water or the ground, while some animals are capable of combining different ways of movement. In the context of mobile robots we are concerned with systems that can move using their locomotion apparatus. The latter very often mimics the one of a human or a certain animal. Copying from biological systems also very often successfully solves some technical problems that arise during artificial locomotion system design.

The other important aspect of a mobile system is that being mobile also means that the distance to the human operator can become large. This implies that the system needs to either possess a certain level of autonomy, meaning that it has to move across the space without the help of the operator, or accept the commands from a distant operator, meaning that the system is able to move tele-operated. Nikola Tesla was the first to design and build a radio-controlled electrical boat (Fig. 1.2) at the end of the 19th century. In the 20th and the 21st century the level of autonomy continuously rose. Yet, all the existing mobile systems are human operated on a certain level.

Fig. 1.2 A working replica of the radio-controlled electrical boat built by Nikola Tesla.

1.1.3 Wheels

Although very primitive animal species are able to move, it is often a nontrivial task to design an artificial system that is able to mimic animal locomotion. While wheels or similar structures cannot be found in the animal world, the vehicles with wheels are known to enable energy-efficient motion over the ground. The surface has to be smooth enough although appropriately constructed wheeled vehicles can also move over rugged terrain, such as steps. It is not known where and when the wheel was invented but the established belief is that the first wheels were used in Mesopotamia approximately 4000 BC. From there, they were spread around the world. Some experts attribute the wheel’s invention to prehistoric Europe. The oldest wooden wheel with an axle, 5200 years old, was discovered in Slovenia in the Ljubljana Marshes (Fig. 1.3).

Fig. 1.3 The 5200-year-old wooden wheel (A) with the axle (B) found in the Ljubljana Marshes pile dwelling is one of the world’s most significant cultural heritage items in terms of both its age and technological accomplishment. The diameter of the wheel is 70 cm and the axle length is 120 cm. (Museum and Galleries of Ljubljana, photos by M. Paternoster.)

1.1.4 Autonomous Mobile Systems

Mobile systems can be defined as systems that are not attached to the environment and can move in a certain space. In terms of the environment they move across they can be classified into some principal groups:

Ground mobile systems Various types of mobile platforms can be found here such as mobile vehicles with wheels or caterpillars, legged robots (humanoids or animal mimicking), or robots that mimic some other type of animal locomotion, for example, snakes. Ground mobile systems with wheels or caterpillars that do not carry the operator are often referred to as unmanned ground vehicles.

Aerial mobile systems This group consists of mobile systems that fly in a certain aerial space (airplanes, helicopters, drones, rockets, animal-mimicking flying systems; ...