Preset Path Dynamics; Limiting The Path Dynamics - Siemens SIMOTION Function Manual

Basics of Path Interpolation
2.6 Path dynamics
2.6.2

Preset path dynamics

The path dynamics can be specified in two different ways in the respective motion command:
● Preset path dynamics via command parameters
● Preset path dynamics via velocity profile/cam
Preset path dynamics via command parameters
The dynamic values (velocity, acceleration, and, if applicable, jerk) are explicitly specified in
the velocity profile type.
The path interpolator calculates the velocity profile for the path motion. Criteria for calculating
the velocity profile include:
● The dynamic values for velocity, acceleration, and jerk specified in the path motion
● The type of velocity profile set in velocityProfile:
Preset path dynamics via velocity profile/cam
The path object can be interconnected with a cam for specifying a velocity profile.
Velocity as well as the derived values for acceleration and, if applicable, jerk, are taken from
the velocity profile.
The base value (domain) is the path length. To rule out rounding errors in the path length
calculation and to enable optimized calculation of profiles over more than one motion,
parameters can be programmed simultaneously for the start and end points of the cam
domain of the respective motion.
At the command end, the dynamics specified in the profile are also applied to the motion.
If additional follow-on motions are programmed, these dynamics are also applied to the
transition to the new motion command. Possible settings for the path behavior at the motion
end are ignored.
If no additional follow-on motions are programmed or if the motion is to stop at the command
end, the dynamics in the profile should be selected such that a stop at the motion end is
possible; a velocity of 0 with a braking dynamic that can be achieved with certainty.
In addition, the profile dynamics are limited by the dynamic values for the individual
commands, taking into account the preassigned velocity profile type.
2.6.3

Limiting the path dynamics

Technological limiting
The individual axis setpoints resulting from the path interpolation are limited to the dynamic
limits specified for each path axis and positioning axis involved in path-synchronous motion.
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command
– TRAPEZOIDAL: Without jerk limitation; the path will be traveled with constant
acceleration and deceleration.
– SMOOTH: With jerk limitation; the path will be traveled with smooth acceleration and
deceleration curve.
TO Path Interpolation
Function Manual, 11/2010