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Chapter

1

Autonomous robots
Both animals and robots manipulate objects in their environment in order to achieve certain goals. Animals use their senses (e.g. vision, touch, smell) to probe the environment. The resulting information, in many cases also enhanced by the information available from internal states (based on short-term or long-term memory), is processed in the brain, oftenresulting in an action carried out by the animal, with the use of its limbs. Similary, robots gain information of the surroundings, using their sensors. The information is processed in the robot’s brain1 , consisting of one or several processors, resulting in motor signals that are sent to the actuators (e.g. motors) of the robot. In this course, the problem of providing robots with the ability ofmaking rational, intelligent decisions will be central. Thus, the development of robotic brains is the main theme of the course. However, a robotic brain cannot operate in isolation: It needs sensory inputs, and it must produce motor output in order to influence objects in the environment. Thus, while it is the author’s view that the main challenge in contemporary robotics lies with the development ofrobotic brains, consideration of the actual hardware, i.e. sensors, processors, motors etc., is certainly very important as well. This chapter gives a brief overview of robotic hardware, i.e. the actual frame (body) of a robot, as well as its sensors, actuators, processors etc. The
The term control system is commonly used (instead of the term robotic brain). However, this term is misleading, asit leads the reader to think of classical control theory. Concepts from classical control theory are relevant in robots; For example, the low-level control of the motors of robots is often taken care of by PI- or PID-regulators. However, autonomous robots, i.e. freely moving robots that operate without direct human supervision, are expected to function in complex, unstructured environments, and tomake their own decisions concerning which action to take in any given situation. In such cases, systems based only on classical control theory are simply insufficient. Thus, hereafter, the term robotic brain (or, simply, brain) will be used when referring to the system that provides an autonomous robot, however simple, with the ability to process information and decide upon which actions to take.1

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CHAPTER 1. AUTONOMOUS ROBOTS

Figure 1.1: Left panel: A Boe-bot. Right panel: A wheeled robot currently under construction
in the Adaptive systems research group at Chalmers.

various hardware-related issues will be studied in greater detail in the second half of the course, which will involve the construction of an actual robot of the kind shown in the left panel of Fig. 1.1.1.1 Robot types
The are many different types of robots, and the taxonomy of such machines can be constructed in various ways. For example, one may classify different kinds of robots based on their complexity, their likeness to humans (or animals), their way of moving etc. In this course we shall limit ourselves to mobile robots, that is, robots that are able to move freely using, for example,wheels. The other main category of robots are stationary robotic arms, also referred to as robotic manipulators. Of course, as with any taxonomy, there are always examples that do not fit neatly into any of the available categories. For example, a smart home equipped with a central computer and, perhaps, some form of manipulation capabilities, can also be considered a robot, albeit of a differentkind. Robotic manipulators constitute a very important class of robots and they are used extensively in many industries, for example in assembly lines in the vehicle industry. However, such robots normally follow a predefined movement sequence and are not equipped with behaviors (such as collision avoidance) designed to avoid harming people. While there is nothing preventing the use of, for...
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