B.8.1 Influence Of The Mass On Force Control - Festo CPX Series Manual

B. Basic controlling principles

B.8.1 Influence of the mass on force control

B−36
The moving mass consists of the workpiece mass and the tool
mass (or basic load). Often the exact basic load is not known.
m = m = m
total current tool mass
As with any other positioning process, the workpiece mass
needs to be specified for the identification, too.
m = m
ident. tool mass ident.
During static identification the controller identifies the force
at which the drive is safely held at a standstill. It also deter
mines the forces that are required to let the drive break away
in both directions of movement. The mean value of these
break−away forces is stored as the standstill force in the
identification data.
If you do not take into account the friction forces, the stand
still force F must only just compensate the force due to
0
weight of the moving mass:
F = p * A p * A
0 01 1 02
The total mass m
ident
stored in the identification data.
During force control, the identified standstill force F
as basic value for the force to be controlled. It compensates
the gravitational force and other external axial forces. Due to
identification (i.e. measurement) of the standstill force F
error in the specification of m
control.
If the user specifies different workpiece masses per record,
the difference m
delta
account and additionally compensated. The workpiece mass
in the records should therefore be specified precisely, so that
the standstill force can be tracked as best as possible.
+ m
current workpiece mass
+ m
workpiece mass ident.
= m * g * sin
2 ident.
specified during identification is also
leads to no error in force
ident.
to the identification mass is taken into
Festo P.BE−CPX−CMA X−CONTROL−EN en 0908NH
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serves
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