ABSTRACT
Robotics is a broad discipline. The breadth of the field becomes apparent by contrasting definitions of robots. In 1979, the Robot Institute of America defined a robot as “a reprogrammable, multifunctional manipulator designed to move materials, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks” (Russell & Norvig, 1995). In contrast, the Merriam Webster’s collegiate dictionary (1993) defines a robot as “An automatic device that performs functions normally ascribed to humans or a machine in the form of a human.” A technical introduction into robotic sensors, actuators, and algorithms can be found elsewhere (e.g., Thrun, 2002).The United Nations (U.N.), in their most recent robotics survey (U.N. and I.F.R.R., 2002), grouped robotics into three major categories. These categories-industrial robotics, professional service robotics, and personal service robotics-are primarily defined through their application domains. These categories also represent different technologies and correspond to different historic phases of robotic development and commercialization.Industrial robots represent the earliest commercial success, with the most widespread distribution to date. An industrial robot has three essential elements: It manipulates its physical environment (e.g., by picking up a part and placing it somewhere else); it is computer controlled; and it operates in industrial settings, such as on conveyor belts. The boundary between industrial robots and non-robotic manufacturing devices is somewhat fuzzy; the term robot is usually used to refer to systems with multiple actuated elements, often arranged in chains (e.g., a robotic arm). Classical applications of industrial robotics include welding, machining, assembly, packaging, palletizing, transportation, and material handling. For example, Figure 1 shows an industrial welding robot in the left panel next to a robotic vehicle for transporting containers on a loading dock in the right panel.Industrial robotics started in the early 1960s, when the world’s first commercial manipulator was sold by Unimate. In the early 1970s, Nissan Corporation automated an entire assembly line with robots, starting a revolution that continues to this day. To date, the vast majority of industrial robots are installed in the automotive industry, where the ratio of human workers to robots is approximately 10:1 (U.N. and I.F.R.R., 2002). The outlook of industrial robots is prosperous. In 2001, the U.N. estimated the operational stock of industrial robots to be 780,600; a number that is expected to grow by just below 25%
until 2005. According to the U.N. (U.N. and I.F.R.R., 2002), the average cost of an industrial robot has decreased by 88.8% between 1990 and 2001. At the same time, U.S. labor costs increased by 50.8%. These opposing trends continue to open up new opportunities for robotic devices to take over jobs previously reserved for human labor. However, industrial robots tend not to interact directly with people. Interface research in this field focuses on techniques for rapidly configuring and programming these robots.Professional service robots constitute much younger kinds of robots. Service robotics is mostly in its infancy, but the field is growing at a much faster pace than industrial robotics. Just like industrial robots, professional service robots manipulate and navigate their physical environments. However, professional service robots assist people in the pursuit of their professional goals, largely outside industrial settings. Some of these robots operate in environments inaccessible to people, such as robots that clean up nuclear waste (Blackmon et al., 1999; Brady et al., 1998) or navigate abandoned mines (Thrun et al., 2003). Others assist in hospitals, such as the HelpMate® robot (King & Weiman, 1990) shown in Figure 2a, which transports food and medication in hospitals; or the surgical robotic system shown in Figure 2b, used for assisting physicians in surgical procedures. Robot manipulators are also routinely used in chemical and biological labs, where they handle and manipulate substances (e.g., blood samples) with speeds and precisions that people cannot match; recent work has investigated the feasibility of inserting needles into human veins through robotic manipulators (Zivanovic & Davies, 2000). Most professional service applications have emerged in the past decade. According to the U.N. (U.N. and I.F.R.R., 2002), 27% of all operational professional service robots operate underwater, 20% perform demolitions, 15% offer medical services, and 6% serve people in agriculture (e.g., by milking cows; see Reinemann & Smith, 2000). Military applications such as bomb diffusal, search and rescue (Casper, 2002), and support of SWAT teams (Jones, Rock, Bums, & Morris, 2002) are of increasing relevance (U.N. and I.F.R.R., 2002). According to the U.N., the total operational stock of professional service robots in 2001 was 12,400, with a 100% growth expectation by 2005. The amount of direct interaction with people is much larger than in the industrial robotics Field, because service robots often share the same physical space with people.Personal service robots possess the highest expected growth rate. According to optimistic estimates (U.N. and I.F.R.R., 2002), the number of deployed personal service robots will grow from 176,500 in 2001 to 2,021,000 in 2005-a stunning 1,145% increase. Personal service robots assist or entertain people in domestic settings or in recreational activities. Examples include robotic vacuum cleaners, lawn mowers, receptionists, robot assistants to elderly and people with disabilities, wheelchairs, and toys. Figure 3 shows two exam-
