What are the key factors used to classify industrial robots?
based on their mechanical structure or topology. In addition, different robot topologies have different numbers of axes and, therefore, different numbers of joints. The number of axes is a key characteristic of industrial robots. The number of axes and their types determines the robot's range of motion. Each axis represents an independent motion or degree of freedom. More degrees of freedom result in a robot being able to move through larger and more complex spaces. Some robot types have a fixed number of degrees of freedom, while others can have different numbers of degrees of freedom. End effectors, also called end-of- arm tooling (EOAT) or "multipurpose manipulators" in ISO 8373, are another important element in most robots. There's a wide range of end effectors, including grippers, dedicated process tools like screwdrivers, paint sprayers, or welders, and sensors, including cameras. They can be pneumatic, electric, or hydraulic. Some end effectors can rotate, giving the robot another degree of freedom. The following sections begin with the IFR definition for each robot topology and then examine their capabilities and applications. Articulated robots have three or more rotary joints.
This is a large class of robots. Articulated robots can have ten or more axes, with six being the most common. Six-axis robots can move in x, y, and z planes and pitch, yaw, and roll rotations, enabling them to mimic the movement of a human arm. They are also available with a wide range of payload capacities from under 1 kg to over 200 kg. The reach capabilities of these robots also vary widely from under 1 meter to multiple meters. For example, the KR 10 R1100-2 from KUKA is a six-axis articulated robot with a maximum reach of 1,101 mm, a maximum payload of 10.9 kg, and a pose repeatability of ±0.02 mm (Figure 1). It also features high-speed movements, short cycle times, and an integrated energy supply system. Articulated robots can be permanently mounted on the floor, wall, or ceiling. They can also be mounted on tracks on the floor or overhead, on top of an autonomous mobile robot or other movable platform, and moved between workstations. They are used for various tasks, including material handling, welding, painting, and inspection. Articulated robots are the most common topology for implementing collaborative robots (cobots) designed to work with humans. While a conventional robot operates in a safety cage
with safety barriers, a cobot is designed for close interaction with people. For example, the LXMRL12S0000 cobot from Schneider Electric has a maximum reach of 1,327 mm, a maximum payload of 12 kg, and a pose repeatability of ±0.03 mm. Cobots often feature collision protection, rounded edges, force limits, and lighter weight for enhanced safety.
Figure 1: Six-axis articulated robot with a pose repeatability of ±0.02 mm. (Image source: DigiKey)
10
Powered by FlippingBook