Vibration Damping With Superimposed Process Loop (Process Control With Intelligent Servo Axis); Task Definition - Application Description; Task Definition; Functional Overview/Concept - Bosch REXROTH IndraDrive Applications Manual

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Rexroth IndraDrive Rexroth IndraMotion MLD Application Examples

Vibration Damping With Superimposed Process Loop (Process Control With Intelligent Servo Axis)

8 Vibration Damping With Superimposed Process Loop
(Process Control With Intelligent Servo Axis)
8.1 Task Definition – Application Description
8.1.1

Task Definition

8.1.2

Functional Overview/Concept

Detecting the Actual Value (Accel‐
eration)
Point at Which the Process Loop
Takes Effect
LSA Control S.L. www.lsa-control.com comercial@lsa-control.com (+34) 960 62 43 01
Using an external sensor, active vibration damping (process control) for low
resonance frequencies is to be implemented by means of "IndraMotion MLD".
The objective is to minimize the vibration behavior of the axis and, consequent‐
ly, to achieve higher contour precision of the axis. In order that the normal
positioning process is not inhibited, the process loop is a cascade superim‐
posed to the drive control loop structure. That is to say, the command value
must continue taking effect in the respective operation mode and a command
value of the process loop is simply added to it.
For this purpose, the MLD-S library "DRIVE_LIB_01V02.lib" makes
available a comprehensive PID loop function block!
Fig.8-1: Functional Concept
The output signal of an acceleration sensor ist to be read in via an analog input
at the IndraDrive control section. This sensor is mounted at a point of the me‐
chanical system which is susceptible to vibration. After the sensor signal has
been adjusted, it is used as the actual value for process control.
It is our objective to reduce the vibration occurring at this point in
order to achieve a better dynamic response and higher production
quality.
The resulting actuating variable of the control loop is added to the command
value. This does not affect the command value input of the external PLC, i.e.
the process loop is superimposed to the drive control loop structure. Thus, an
external PLC always has Motion Control over the drive.
For the point at which the command value takes effect in the drive cascade
structure, the following additive command values are available:
● P‑0‑0059, Additive position command value, controller
● S‑0‑0037, Additive velocity command value
● S‑0‑0081, Additive torque/force command value
The paragraphs below describe the steps required to solve the task and show
how to create a simple program. The developed program, however, does not
contain any error handling.
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