Universal Robots UR3/CB3 User Manual page 162

waypoints.
WP_1
Figure 14.6: Joint space (MoveJ) vs. cartesian space (MoveL) movement and blend.
Of the different combinations, bullets 2, 3 and 4 will result in trajectories that keep
within the boundaries of the original trajectory in Cartesian space. An example of a
blend between different trajectory types (bullet 2) can be seen in figure 14.7.
Figure 14.7: Blending from a movement in joint space (MoveJ) to linear tool movement (MoveL).
Pure joint space blends (bullet 1), however, may behave in a way that is less intuitive,
since the robot will try to achieve the smoothest possible trajectory in Joint space taking
velocities and time requirements into account. Due to this, they may deviate from the
course specified by the waypoints. This is especially the case if there are significant
differences in a joint's velocity between the two trajectories. Caution: if the velocities
are very different (e.g. by specifying advanced settings - either velocity or time - for
a specific waypoint) this can result in large deviations from the original trajectory as
shown in figure 14.8. If you need to blend between different velocities and cannot
accept this deviation consider a blend in Cartesian space using MoveL instead.
CB3
WP_2
WP_3
WP_1
II-78
14.6 Command: Fixed Waypoint
WP_1
WP_2
WP_3
WP_2
WP_3
Version 3.3.3