An assessment of industrial robots: Capabilities, economics, and impacts

Abstract

Abstract Production managers and engineers have always tried to find better and less expensive ways of making a product. In recent years their search has led them to consider the use of robots for jobs previously thought to require more judgment and flexibility than a machine can offer. Before robots are introduced onto the factory floor, though, their capabilities and limitations should be fully understood, and an effective implementation plan devised. The purpose of this article is to examine some of the important issues underlying this growing technology and to assess its impacts. In particular, robots have a variety of virtues that go beyond simple cost savings. In many cases they relieve factory workers of tasks that are tediously repetitive or dangerous. From management's viewpoint, though, a robot is justified only when a practical application exists. The simple transfer of objects between work stations, storage facilities, and transport systems was one of the first such applications. In high volume production these “pick and place” operations must be performed accurately and consistently, making them ideal for automation. Though largely an American invention, robots have not taken their place in many domestic factories as fast as they have abroad. Many companies have been reluctant to make the initial investment, particularly when faced with a surplus of capacity and labor, and no pressure to hold down prices. Now, however, heightened competition in many industries previously thought to be secure from foreign intrusion has led to a change in attitude. The need to hold on to existing markets, and in some cases even catch up, has inspired many doubters to take a second look. Not surprisingly, this has brought forth charges that some employers, lacking in social conscience, are substituting machines for people and adding to the nation's jobless roles. The issue has been on the table in labor‐management disputes for decades with the machines generally winning out. To a large extent, the residue of unemployment that remains in the economy even in the best of times reflects the effect of change and the problems of adjusting to it. To date there is no evidence that an accelerated introduction of robotics will cause any noticeable disruption in the labor force. Although there may be isolated instances of dislocation, a management sensitive to the concerns of its workers should be able to make the transition smoothly, perhaps allowing excess personnel to shrink through attrition rather than layoff while retraining as many as possible. If we trace the history of programmable devices, we see that most of the early mechanisms were developed by the machine‐tool industry. By today's standards, this equipment was slow, heavy, and precise, and was driven by very simple algorithms stored on paper or magnetic tape. Virtually no on‐line decision‐making capability existed and only fixed, repetitive motions were possible. Still, being programmable automation, these machines could be considered the first robots. As microelectronics became more refined, the repertoire of robot manipulators was extended to include more complex tasks. For example, acts requiring considerable on‐line processing such as the creation of straight line motion and the initiation of movement in response to sensed input are now straightforward to implement. To understand better what distinguishes robots from their machine tool predecessors, an examination of their basic features is needed. All robots are composed of three interdependent components: manipulators, a power supply, and a controller. The manipulator is the mechanical structure consisting of linkages and joints that provide motion along different axes. Each separate axis is called a “degree of freedom.” The manipulator, or “arm,” usually has three degrees of freedom while an attachment to the arm, called the “end effector” or “hand,” can furnish an additional three. Still, a seventh degree of freedom can be