CIndustrial robots used in construction

An industrial robot is officially defined by ISO^[1] 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.

Industrial robot types, features

The most commonly used robot configurations for industrial automation, include articulated robots (The first 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.

Technical description

Defining parameters

• 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. It can be improved by Robot calibration.
• motion control – for some applications, such as simple pick-and-place assembly, the robot need merely return repeatably to a limited number of pre-taught positions. For more sophisticated applications, such as arc welding, motion must be continuously controlled to follow a path in space, with controlled orientation and velocity.
• power source – some robots use electric motors, others 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).

Recent and future developments

As of 2005, the robotic arm business is getting to a mature state, where they can provide enough speed, accuracy and ease of use for most of the applications. Vision guidance (aka machine vision) is bringing a lot of flexibility to robotic cells. So we have the arm and the eye, but the part that still has poor flexibility is the hand: the end effector attached to a robot is often a simple pneumatic, 2-position wrench. This doesn't allow the robotic cell to easily handle different parts, in different orientations.

Hand in hand with increasing off-line programmed applications, Robot calibration is becoming more and more important in order to guarantee a good positioning accuracy.

Other developments include downsizing industrial arms for consumer applications and using industrial arms in combination with more intelligent Automated Guided Vehicles (AGVs) to make the automation chain more flexible between pick-up and drop-off.

Prices of industrial robots will vary with the features, but are usually about 20,000 USD for an entry level model, and as much as 100,000 or more for a heavy-duty, long range robot..

Notes

1. ↑  ISO Standard 8373:1994, Manipulating Industrial Robots – Vocabulary

See also

• List of production topics
• Autonomous robot

References

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