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XPS-Q8 Controller
7.0
Motion
7.1
Motion Profiles
Motion commands refer to strings sent to a motion controller that will initiate a motion.
The XPS controller provides several modes of positioning from simple point-to-point
motion to the most complex trajectories. On execution of a motion command, the
positioner moves from the current position to the desired destination. The exact
trajectory for the motion is calculated by a motion profiler. So the motion profiler
defines where each of the positioners should be at each point in time. There are details
worth mentioning about the motion profiler in the XPS controller:
In a classical trapezoidal motion profiler (trapezoidal velocity profile), the acceleration
is an abrupt change. This sudden change in acceleration can cause mechanical
resonance in a dynamic system. In order to eliminate the high frequency portion of the
excitation spectrum generated by a conventional trapezoidal velocity motion profile, the
XPS controller uses a sophisticated SGamma motion profile. Figure 17 shows the
acceleration, velocity and position plot for the SGamma profile.
The SGamma motion profile provides better control of dynamic systems. It allows for
perfect control of the excitation spectrum that a move generates. In a multi-axes system
this profile gives better control of each axis independently, but also allows control of the
cross-coupling that are induced by the combined motion of the axes. As shown in figure
17, the acceleration plot is parabolic. The parabola is controlled by the jerk time (jerk
being the derivative of the acceleration). This parabolic characteristic of the acceleration
Figure 17: SGamma Motion Profile.
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XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
Motion Tutorial
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