Using A Feature - Universal Robots e Series User Manual

16.3 Features
Some subparts of a robot program consist of movements executed relative to specific objects other
than the base of the Robot arm. These objects could be tables, other machines, workpieces, con-
veyors, pallets, vision systems, blanks, or boundaries which exist in the surroundings of the Robot
arm. Two predefined features always exist for the robot. Each feature has its pose defined by the
configuration of the Robot arm itself:
• The Base feature is located with origin in the centre of the robot base (see figure 16.1)
• The Tool feature is located with origin in the centre of the current TCP (see figure 16.2)
Figure 16.1: Base feature
User-defined features are positioned through a method that uses the current pose of the TCP in the
work area. This means the users can teach feature locations using Freedrive Mode or "jogging" to
move the robot to the desired pose.
Three different strategies exist (Point, Line and Plane) for defining a feature pose. The best strategy
for a given application depends on the type of object being used and the precision requirements. In
general a feature based on more input points (Line and Plane) is be preferred if applicable to the
specific object.
To accurately define the direction of a linear conveyor, define two points of a Line feature with as
much physical separation as possible. The Point feature can also be used to define a linear conveyor,
however, the user must point the TCP in the direction of the conveyor movement.
Using more points to define the pose of a table means that the orientation is based on the positions
rather than the orientation of a single TCP. A single TCP orientation is harder to configure with high
precision.
To learn about the different methods to define a feature see (sections: 16.3.2), (16.3.3) and
(16.3.4).

16.3.1 Using a feature

When a feature is defined in the installation, you can refer to it from the robot program to relate robot
movements (e.g. MoveJ, MoveL and MoveP commands) to the feature (see section 15.5.1).
This allows for easy adaptation of a robot program (e.g., when there are multiple robot stations,
when an object is moved during program runtime, or when an object is permanently moved in the
scene). By adjusting the feature of an object, all program movements relative to the object is moved
accordingly. For further examples, see (sections 16.3.5) and (16.3.6).
Version 5.4
Figure 16.2: Tool (TCP) feature
II-105 e-Series