Hello :) I wonder If the attached graphic describes the meaning of FERROR & MIN_FERROR variables??.
That is, motion will be aborted for a given velocity if absolute value
of actual and commanded position diference is over the black line.
I suppouse also that this difference is measured in joint coordinates
because if forward dynamic model is not available there wouldn't be a
method to know comanded position in axis (machine) coordinates. Do you
agree? (I'm working with a parallel kinematics machine and diference
matters)
A completely different question: Is Integrator's manual an augmented
User Manual?. In other words, do I miss somethig if I don't read User
Manual if I read Integrator's Manual?.
Thanks in advance
Javier Ros
PD:
For reference this is what Integrator's manual says
MIN_FERROR = 0.010 This is the value in machine units by which the axis
is permitted to deviate
from commanded position at very low speeds. If MIN_FERROR is smaller
than FERROR, the
two produce a ramp of error trip points. You could think of this as
a graph where one dimension
is speed and the other is permitted following error. As speed
increases the amount of following
error also increases toward the FERROR value.
FERROR = 1.0 FERROR is the maximum allowable following error, in machine
units. If the differ-
ence between commanded and sensed position exceeds this amount, the
controller disables
servo calculations, sets all the outputs to 0.0, and disables the
amplifiers. If MIN_FERROR is
present in the .ini file, velocity-proportional following errors are
used. Here, the maximum al-
lowable following error is proportional to the speed, with FERROR
applying to the rapid rate set
by [TRAJ]MAX_VELOCITY, and proportionally smaller following errors
for slower speeds. The
maximum allowable following error will always be greater than
MIN_FERROR. This prevents
small following errors for stationary axes from inadvertently
aborting motion. Small following
errors will always be present due to vibration, etc. The following
polarity values determine how
inputs are interpreted and how outputs are applied. They can usually
be set via trial-and-error
since there are only two possibilities. The EMCMOT utility program
USRMOT can be used to
set these interactively and verify their results so that the proper
values can be put in the INI
file with a minimum of trouble.
<<attachment: ferror-min_ferror.png>>
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