Electronic line shaft with phased lock loop filtering and predicting
AssigneeRockwell Automation Technologies, Inc.
InventorsSteven Michael Wirtz, Thomas J. Rehm
Life of this patent
Estimating the term…
Abstract
An improved electronic line shaft provides for a predictor sending predicted position and/or velocity values to servant drives that may be later strobed in by high speed low-latency strobe signals to eliminate network jitter and delay. The predictor may be implemented as a phase lock loop, providing filtering of a master encoder signal together with flexible electronic gear ratio adjustments and other desired control refinements.
Claims31
An electronic line shaft systems comprising:
- multiple servant motor drives receiving a position signal and a strobe signal and connectable to corresponding motor-driven line shafts to synchronize a position of the line shafts to the position signal at a time of the strobe signal;
- a master controller receiving a position signal from an encoder indicating the position of a master line shaft;
- a network communicating between the multiple servant motor drives and the master motor drive, the network having a communication delay;
- a synchronizing system including a predictor accepting the position signal from the master controller and providing a predicted position signal to the servant motor drives together with a strobe signal, the predicted position signal representing a prediction of a future position of the motor at a predetermined time in the future coinciding with a time of the strobe signal;
- whereby the communication delay may be corrected.
A master controller for an electronic line shaft system having multiple servant motor drives communicating with the master controller through a network having a communication delay, the servant drives receiving a position signal and a strobe signal and connectable to an electric motor to synchronize the motor to the position of the position signal at a time of the strobe signal, wherein the master controller comprises:
- a strobe generator periodically generating the strobe signal;
- a predictor accepting a position signal from an encoder and providing a predicted position signal, the predicted position signal representing a prediction of a future position of the motor at a predetermined time in the future coinciding with a time of the strobe signal;
- whereby the communication delay may be corrected.
An encoder signal conditioner comprising:
- an encoder input for receiving a periodic position signal from an encoder;
- a phase locked loop including:
- (i) an electronically controllable virtual encoder outputting a conditioned encoder output according to a frequency input,
- (ii) a phase comparator receiving the conditioned encoder output and the periodic position signal to produce a phase difference signal providing the frequency input to the electronically controllable virtual encoder;
- and
- a position output for providing the condition encoder output to motor drives.
Dependencies are inferred from the claim text.