US 11,722,081 B1
System and method for determining a cyclic disturbance in an industrial control system
Jonathan D. Hoffman, Milwaukee, WI (US); and Adam M. Shea, Fox Point, WI (US)
Assigned to Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US)
Filed by Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US)
Filed on Jan. 25, 2022, as Appl. No. 17/584,006.
Int. Cl. H02P 6/22 (2006.01); H02P 21/14 (2016.01); H02P 6/16 (2016.01); H02P 27/06 (2006.01)
CPC H02P 21/14 (2013.01) [H02P 6/16 (2013.01); H02P 27/06 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for dynamic observation of a cyclic disturbance in a controlled machine or process, the method comprising the steps of:
receiving a command signal at a motor drive, wherein the command signal corresponds to a desired operation of a motor operatively controlled by the motor drive;
receiving a cycle position signal at the motor drive, wherein the cycle position signal corresponds to a location within one cycle of operation of the controlled machine or process and wherein the cycle of operation does not correspond to one rotation of the motor;
determining a value of an estimated acceleration resulting from a disturbance force experienced by the motor during the cycle of operation; and
storing the value of the estimated acceleration in memory of the motor drive at a plurality of sample instances within the cycle of operation.
 
9. A motor drive configured to dynamically observe a cyclic disturbance in a controlled machine or process, the motor drive comprising:
at least one input configured to receive a command signal and a cycle position signal, wherein the command signal corresponds to a desired operation of a motor operatively connected to the motor drive and the cycle position signal corresponds to a location within one cycle of operation of the controlled machine or process;
a memory configured to store a look up table; and
a processor configured to:
determine a value of an estimated acceleration resulting from a disturbance force experienced by the motor during the cycle of operation, and
store the value of the estimated acceleration in the look up table at a plurality of sample instances within the cycle of operation.
 
16. A method for dynamic compensation of a cyclic disturbance in a controlled machine or process, the method comprising the steps of:
receiving a command signal at a motor drive, wherein the command signal corresponds to a desired operation of a motor operatively controlled by the motor drive;
receiving a cycle position signal at the motor drive, wherein the cycle position signal corresponds to a location within one cycle of operation of the controlled machine or process and wherein the cycle of operation does not correspond to one rotation of the motor;
reading a disturbance value from a look up table stored in a memory of the motor drive, wherein the disturbance value corresponds to the cycle position signal; and
executing a control module within the motor drive responsive to receiving the command signal to obtain the desired operation of the motor, wherein the disturbance value is provided to the control module to reduce a tracking error in the control module.