Industrial robot

An industrial robot is officially defined by ISO (Standard 8373:1994, Manipulating Industrial Robots – Vocabulary) as an automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes. The field of industrial robotics may be more practically defined as the study, design and use of robot systems for manufacturing (a top-level definition relying on the prior definition of robot).

Typical applications of industrial robots include welding, painting, ironing, assembly, pick and place, palletizing, product inspection, and testing, all accomplished with high endurance, speed, and precision. Manufacturers of industrial robots include: Intelligent Actuator, Adept, Epson Robots, Yaskawa-Motoman, ABB, EPSON-SEIKO, igm Robotersysteme, KUKA, Kawasaki and FANUC Robotics

Industrial robot types, features

The most commonly used robot configurations for industrial automation, include articulated robots (the original, and most common), SCARA robots and gantry robots (aka Cartesian Coordinate robots, or x-y-z robots). In the context of general robotics, most types of industrial robots would fall into the category of robot arms (inherent in the use of the word manipulator in the above-mentioned ISO standard).

Industrial robots exhibit varying degrees of autonomy. Robots are programmed to faithfully do specific actions over and over again without variation and with a high degree of accuracy. These actions are determined by programmed routines that specify the direction, acceleration, velocity, deceleration, and distance of a series of coordinated motions. Other industrial robots are much more flexible as to the orientation of the object on which they are operating or even the task that has to be performed on the object itself, which the robot may even need to identify. For example, for more precise guidance, robots often contain machine vision sub-systems acting as their "eyes", linked to powerful computers or controllers. Artificial intelligence, or what passes for it, is becoming an increasingly important factor in the modern industrial robot.

Robot programming

The setup or programming of motions and sequences for an industrial robot is typically taught by linking the robot controller via communication cable to the serial port of a laptop computer. The PC is installed with corresponding interface software. The use of the PC greatly simplifies the programming process. Robots can also be taught via teaching pendant, a handheld control and programming unit. The teaching pendant or PC is usually disconnected after programming and the robot then runs on the program that has been installed in its' controller. In addition, machine operators often use "HMI" human-machine-interface devices, typically touch screen units, which serve as the operator control panel. The operator can switch from program to program, make adjustments within a program and also operate a host of peripheral devices that may be integrated within the same robotic system. These peripheral devices include robot end effectors which are devices that can grasp an object, usually by vacuum, electromechanical or pneumatic devices. Also emergency stop controls, machine vision systems, safety interlock systems, bar code printers and an almost infinite array of other industrial devices are accessed and controlled via the operator control panel.

test

Characteristics of industrial robots

number of axes – two axes are required to reach any point in a plane; three axes are required to reach any point in space. To fully control the orientation of the end of the arm (i.e. the wrist) three more axes (roll, pitch and yaw) are required. Some designs (e.g. the SCARA robot) trade limitations in motion possibilities for cost, speed, and accuracy.
kinematics – the actual arrangement of rigid members and joints in the robot, which determines the robot's possible motions. Classes of robot kinematics include articulated, cartesian, parallel and SCARA.
working envelope – the region of space a robot can reach.
carrying capacity – how much weight a robot can lift.
speed – how fast the robot can position the end of its arm.
accuracy – how closely a robot can reach a commanded position. Accuracy can vary with speed and position within the working envelope.
power source – some robots use electric motors, other use hydraulic actuators. The former are faster, the later are stronger and advantageous in applications such as spray painting, where a spark could set off an explosion.
drive – some robots connect electric motors to the joints via gears; others connect the motor to the joint directly (direct drive).

History of industrial robotics

The first company to produce an industrial robot was Unimation, founded by Joseph F. Engelberger in 1962, with the basic inventions of George Devol. Unimation robots were also called programmable transfer machines since their main use at first was to transfer objects from one point to another, less than a dozen feet or so apart. They used hydraulic actuators and were programmed in joint coordinates, i.e. the angles of the various joints were stored during a teaching phase and replayed in operation. For some time Unimation's only competitor was Cincinnati Milacron Inc. of Ohio. This changed radically in the late 1970s when several big Japanese conglomerates began producing similar industrial robots. Unimation had obtained patents in the United States but not in Japan, so their designs were copied and then improved upon in that country.

In 1969 Victor Sheinman at Stanford University invented the Stanford arm, an all-electric, 6-axis articulated robot designed to permit an arm solution. This allowed the robot to accurately follow arbitrary paths in space and widened the potential use of the robot to more sophisticated applications such as assembly and arc welding. Sheinman sold his design to Unimation who further developed it with support from General Motors and later sold it as the PUMA (Programmable Universal Machine for Assembly).

Interest in industrial robotics swelled in the late 1970s and many companies entered the field, including large firms like General Electric, and General Motors (which formed joint venture FANUC Robotics with FANUC LTD of Japan). US start-ups included Automatix and Adept. At the height of the robot boom in 1984, Unimation was acquired by Westinghouse for 107 million US dollars. Westinghouse sold Unimation to Stäubli Faverges SCA of France in 1988. Stäubli was still making articulated robots for clean room applications as of 2004.

Eventually the deeper long term financial resources and strong domestic market enjoyed by the Japanese companies prevailed, their robots spread all over the globe. Only a few non-Japanese companies managed to survive in this market, including Adept, Stäubli-Unimation, the Swedish-Swiss company ABB (ASEA Brown-Boveri), the Austrian manufacturer igm Robotersysteme AG and the German company KUKA.

References

Nof, Shimon Y. (editor) (1999). Handbook of Industrial Robotics, 2nd ed. John Wiley & Sons. ISBN 0471177830.
A comprehensive reference on the categories and applications of industrial robotics. 1378 pages.

Industrial robot