Image 7.75: “Hydraulic - position control” screen PosCon_pLimit(2)
Position control without volumetric flow control:
If the cylinder geometry is unknown, then no feed-forward control value can be
calculated for the volumetric feed-forward control. In this case, a PI controller and a
constant speed feed-forward control can be used to represent the position control
(P 2840.12 AltPosCon = PosCon_nFF(1)). However, the different surfaces of the
cylinder geometry must be taken into account because the different volumes of the
cylinder chambers cause different control paths. To do so, the control parameters of
the position control must be adapted. The control can be designed to suit the
different cylinder surface sizes using parameters P 2870.3 KpScale and P 2870.5
KpScaleNeg.
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
205
7 Control
Image 7.76: “Hydraulic - position control” screen PosCon(1)
Position control with tracking error switchover:
For special applications, the control parameters can be changed as a function of a
tracking error limit. To do so, a switchover limit (P 2878.2 PosWindowP) must be
configured in which the controller gain is influenced by means of a second scaling
factor (P 2878.1 KpScale2). In addition, the I-component can also be influenced by
means of a scaling factor which becomes active as of a certain switchover limit. The
feed forward control as well as the pressure limitation continue to remain active for
this control structure.
