Basic Characteristics RAPID

Singularity points/IRB 6400C
Between the robot’s working space, with the arm directed forward and the arm
directed backward, there is a singularity point above the robot. There is also a
singularity point on the sides of the robot. These points contain a singularity and have
kinematic limitations. A position in these points cannot be specified as forward/
backward and can only be reached with MoveAbsJ. When the robot is in a singular
point:
- It is only possible to use MoveAbsJ or to jog the robot axis by axis.
5.1 Program execution through singularities
During joint interpolation, the robot never has any problem passing singular points.
When executing a linear or circular path close to a singularity, the velocities in some
joints (1 and 6/4 and 6) may be very high. In order not to exceed the maximum joint
velocities, the linear path velocity is reduced.
The high joint velocities may be reduced by using the mode (Sing Area\Wrist) when
the wrist axes are interpolated in joint angles while still maintaining the linear path of
the robot tool. An orientation error compared to the full linear interpolation is however
introduced.
Note that the robot configuration changes dramatically when the robot passes close to
a singularity with linear or circular interpolation. In order to avoid the reconfiguration,
the first position on the other side of the singularity should be programmed with an
orientation that makes the reconfiguration unnecessary.
Also note that the robot should not be in its singularity when external joints only are
moved, as this may cause robot joints to make unnecessary movements.
5.2 Jogging through singularities
During joint interpolation, the robot never has any problem passing singular points.
During linear interpolation the robot can pass singular points but at a decreased speed.
5.3 Related information
Described in:
Controlling how the robot is to act on Instructions - SingArea
execution near singular points
RAPID Reference Manual 6-37