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Über dieses Buch

Robots are increasingly being used in industry to perform various types of tasks. Some of the tasks performed by robots in industry are spot welding, materials handling, arc welding, and routing. The population of robots is growing at a significant rate in various parts of the world; for example, in 1984, a report published by the British Robot Association indicated a robot popula­ tion distribution between Japan (64,600), Western Europe (20,500), and the United States (13,000). This shows a significant number of robots in use. Data available for West Germany and the United Kingdom indicate that in 1977 there were 541 and 80 robots in use, respectively, and in 1984 these numbers went up to 6600 and 2623, respectively. Just as for other engineering products, the reliability and safety of robots are important. A robot has to be safe and reliable. An unreliable robot may become the cause of unsafe conditions, high maintenance costs, inconvenience, etc. Robots make use of electrical, mechanical, pneumatic, electronic, and hydraulic parts. This makes their reliability problem a challenging task because of the many different sources of failures. According to some published literature, the best mean time between failures (MTBF) achieved by robots is only 2500 hours. This means there is definite room for further improvement in robot reliability. With respect to safety, there have been five fatal accidents involving robots since 1978.

Inhaltsverzeichnis

Frontmatter

1. Introduction

Abstract
Ancient history concerning robots can be traced back almost 5000 years to when the Egyptians built water-powered clocks and the Chinese and Greeks built water- and steam-powered toys. However, Greece can be credited for generating the idea of the functional robot. This is stated in the writings of Aristotle in the fourth century B.C. in which he wrote [1]: “If every instrument could accomplish its own work, obeying or anticipating the will of others….” It took over 2000 years to put the idea developed in Greece into practice.
B. S. Dhillon

2. Introduction to Reliability and Safety

Abstract
Nowadays, increasing attention is being given to both reliability and safety, more than ever before. There are several factors for this phenomenon: cost, criticality, stringent mission requirements, government requirements, complexity, size, etc.
B. S. Dhillon

3. Introduction to Robotics

Abstract
The great advances in technology of the past decades have resulted in largely automated industrial processes with ever-decreasing degrees of human operator participation. It is probably safe to state that fully automated factories are only decades away. Robots provide manufacturers with more flexibility than other types of automation. Furthermore, the cost associated with robots has been decreasing at a significant rate over the years. For example, Unimation Inc. [1] claims that in 1981, in the United States automotive industry, a robot’s hourly cost was about 30% of the labor costs in 1966.
B. S. Dhillon

4. Robot Accidents

Abstract
An accident is an undesired and unplanned event, and there is hardly a day in which the news media does not report accidents. These reported accidents are generally major and the minor ones never get reported. Each year thousands of lives are lost and disabling injuries occur through work-related and other accidents. For example, in the United States alone approximately 2,200,000 disabling work injuries occurred in 1980. Out of this total, approximately 13,000 were fatal and 80,000 led to some kind of permanent impairment [1]. A breakdown of the injuries to eyes, head, arms, trunk, hands, fingers, legs, feet, and toes were 110,000, 130,000, 200,000, 640,000, 150,000, 330,000, 290,000, 110,000, and 40,000, respectively. The figure for injuries of a general nature was 200,000.
B. S. Dhillon

5. Fundamentals of Robot Safety

Abstract
Today robots are used in many different areas and applications, and their safety-related problems have increased significantly. Each new area and application may call for specific precautions for operators, maintenance workers, robot systems, and so on. In the past, robot safety did not receive as much attention as it deserved from both manufacturers and users. This scenario is changing in recent years, and robot-related accidents could be one of the factors behind this change. The establishment of the American National Standard for Industrial Robots and Robot Systems: Safety Requirements [1] and the Japanese Industrial Safety and Health Association document [2] entitled, “An Interpretation of the Technical Guidance on Safety Standards in the Use, etc., of Industrial Robots” are two prime examples of robot safety consciousness in recent years. In fact, safety standards for industrial robots are under discussion in several countries, and the International Organization for Standardization (ISO) has already expended considerable effort in this direction.
B. S. Dhillon

6. Topics in Robot Safety

Abstract
In recent times there has been a significant growth in the awareness of safety in industry. The prime reason for this is the huge sum of money as remuneration for accidents as the result of litigation [1]. Governments in various parts of the world have enacted laws to regulate this situation. As a result of such laws, both manufacturers and users have accelerated their efforts to promote safety. The use of robots in hazardous industrial conditions is one example of the accelerated efforts to promote safety. In simple terms, a robot may be described as a machine composed of three major subsystems: a power supply, a manipulator, and a controller. The application of such machines in the industrial sector has introduced its own associated safety problems. Over the years, many robot related accidents have occurred [2]-[6] and there have been many reasons for their occurrence, as concluded by various authors. The subject of robot accidents is studied in great depth in Chapter 4 of this book.
B. S. Dhillon

7. Human Factors in Robotics

Abstract
The term “human factors” may simply be described [1] as the study of relationships between new technology’s products and processes and the people who make use of them. Frederick W. Taylor, the father of scientific management, would probably be called the first human factors engineer because he performed studies to determine the most suitable designs for shovels [2]. The government of the United States has played a pivotal role in the development of the human factors field, by establishing laboratories at the Wright-Patterson Air Force Base and the Brooks Air Force Base, to carry out human factors-related research. During the years of World War II engineering systems became highly complex and the requirement for the human factors consideration became a necessity. By the mid-1940s human factors engineering began to be recognized as a specialized discipline.
B. S. Dhillon

8. Robot Reliability

Abstract
The subject of robot reliability is very complex and there are numerous interlocking variables in evaluating and accomplishing various reliability levels. A successful robot installation has to be safe and reliable. A robot with poor reliability leads to many problems: high maintenance cost, unsafe conditions, inconvenience, and so on. Nevertheless, the American National Standard for Industrial Robots and Robot Systems—Safety Requirements [1] specifically calls for the design and construction of robots in such a way that any single, reasonably foreseeable failure will not lead to the robot’s hazardous motion. There are many different types of parts which are used in robots: electrical, electronic, hydraulic, pneumatic, and mechanical. This makes the task of producing highly reliable robots rather a challenging one. Furthermore, the environments in which the robots have to operate may be harsh and may vary enormously from one installation to another even for identical models.
B. S. Dhillon

9. Robot Maintenance

Abstract
Robots are complex and sophisticated machines with good reliability in general. Nevertheless, occasionally these machines do fail and require maintenance just as in the case of other sophisticated engineering systems. Therefore, the users of robots have to devise a sound maintenance program, otherwise their unscheduled downtime may increase beyond limit, consequently defeating the purpose of robot applications. In addition, a poor maintenance program may also lead to safety-related problems.
B. S. Dhillon

10. Failure Data and Analysis

Abstract
The failure data of items provide invaluable information to concerned professionals and management alike. The amount of reliability-related effort put in during the design and manufacture phases of a product is normally indicated by its failure data. Today, there are several failure data banks in existence throughout the world. They are concerned with electrical, electronics, mechanical items, human error, etc.
B. S. Dhillon

11. Robot Economics

Abstract
The robot industry of the future is expected to grow at a spectacular rate. At the beginning of the 1980s the prediction for the growth rate in the installation of robots was of the order of 30% to 35% [1] and it was expected to go well into the next decade (the 1990s). Estimates of industrial sales potential for the year 1990 vary from $2 billion to $4 billion. In 1980, in the Unites States, the volume of robot industry sales was approximately $100 million.
B. S. Dhillon

12. Robot Testing and Information Related to Robots

Abstract
Testing is an important aspect associated with robots. This may be performance testing, reliability testing, or any other type of testing. In this Chapter, we will deal with robot performance and reliability testing in particular. There are several types of performance testing techniques which have been used since the inception of the robot [1], [2]. The forms of performance testing vary from the verification of the design goals by the robot manufacturer to the determination of the most appropriate robot for a specific use. The purpose of the robot reliability testing program is to obtain knowledge of failures—in particular, robot failure occurrence patterns. Robot reliability tests may be categorized into three broad groups [2]: reliability development and demonstration testing, qualification and acceptance testing, and operational testing.
B. S. Dhillon

Backmatter

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