Basic Characteristics RAPID

Coordinate Systems Motion and I/O Principles
Coordination of base coordinate system
A movable coordinate system can also be defined for the base of the robot. This is of
interest for the installation when the robot is mounted on a track or a gantry, for
example. The position and orientation of the base coordinate system will, as for the
moveable user coordinate system, be dependent on the movements of the external unit.
The programmed path and speed will be related to the object coordinate system (Figure
7) and there is no need to think about the fact that the robot base is moved by an external
unit. A coordinated user coordinate system and a coordinated base coordinate system
can both be defined at the same time.
User coordinate system
World coordinate
system
Track
Base coordinate system
Figure 7 Coordinated interpolation with a track moving the base coordinate system of the robot.
To be able to calculate the user and the base coordinate systems when involved units
are moved, the robot must be aware of:
- The calibration positions of the user and the base coordinate systems
- The relations between the angles of the external axes and the translation/rotation
of the user and the base coordinate systems.
These relations are defined in the system parameters.
Object coordinate system
1.3 Coordinate systems used to determine the direction of the tool
The orientation of a tool at a programmed position is given by the orientation of the tool
coordinate system. The tool coordinate system is referenced to the wrist coordinated
system, defined at the mounting flange on the wrist of the robot.
6-8 RAPID Reference Manual