Method for maintenance of a transportation device, software program, and controller

Patent metadata

Field	Value
Publication number	US-10769867-B2
Application number	US-201816199359-A
Country	US
Kind code	B2
Filing date	Nov 26, 2018
Priority date	Dec 22, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Maintenance of a transportation device propelled by an electric motor, wherein an incremental encoder senses motion of a moving part of, or a part moved by, the electric motor, may include acquiring a pulses-per-rotation configuration value PPRconf, representing a quantity of pulses which should be provided by the incremental encoder per one rotation of the electric motor; deriving a pulses-per-rotation estimation value PPRest representing a quantity of pulses provided by the incremental encoder per one rotation of the electric motor; determining a pulses-per-rotation error value PPRerr representing a deviation of the pulses-per-rotation estimation value PPRest from the pulses-per-rotation configuration value PPRconf, based on a relation: PPRerr=PPRest−PPRconf, PPRconf−PPRest, PPRest/PPRconf, or PPRconf/PPRest; and utilizing the pulses-per-rotation error value PPRerr to generate an instance of maintenance information indicating that a maintenance operation should be performed on the transportation device.

First claim

The invention claimed is:

1. A method for operation of a maintenance system that includes an electric motor, a transportation device propelled by the electric motor, and an incremental encoder configured to sense motion of a moving part of the electric motor or a part moved by the electric motor, the electric motor configured to be controlled according to a motor model, the method comprising:
acquiring a pulses-per-rotation configuration value (PPRconf), the pulses-per-rotation configuration value PPRconf being a drive parameter of the incremental encoder and representing a nominal/configured quantity of pulses which should be provided by the incremental encoder per one rotation of the electric motor when the incremental encoder is operating according to normal operation;
deriving a pulses-per-rotation estimation value (PPRest), the pulses-per-rotation estimation value PPRest representing an estimated quantity of pulses actually provided by the incremental encoder per one rotation of the electric motor, based on estimating speed and position of the electric motor independently of an encoder signal proved by the incremental encoder, based on the motor model used to control the electric motor;
determining a pulses-per-rotation error value (PPRerr), the pulses-per-rotation error value PPRerr representing a deviation of the pulses-per-rotation estimation value PPRest from the pulses-per-rotation configuration value PPRconf, based on a relation that is one of
PPRerr=PPRest−PPRconf,

PPRerr=PPRconf−PPRest,

PPRerr=PPRest/PPRconf, or
PPRerr=PPRconf/PPRest;

utilizing the pulses-per-rotation error value PPRerr to generate an instance of maintenance information indicating that a maintenance operation should be performed on the transportation device, and
transmitting the instance of maintenance information as
a message to a remote device, the message including a request to preform the maintenance operation, or
a control signal to a control device to cause the control device to preform the maintenance operation based on controlling the transportation device and/or the electric motor.

2. The method of claim 1 , wherein
the pulses-per-rotation configuration value PPRconf is acquired based on a separate relation including a pulses-per-rotation of encoder wheel by design value (PPRenc) that is a quantity of pulses per one rotation of a measuring wheel axis of the incremental encoder, and a nominal transmission ration (r) between the measuring wheel axis of the incremental encoder and drive axis of the electric motor, and
the relation is PRRconf=r×PPRenc.

3. The method of claim 1 , wherein the deriving the pulses-per-rotation estimation value PPRest includes
determining a stator current of a stator winding of the electric motor;
determining a stator voltage of the stator winding of the electric motor;
determining a magnetic pole position of a magnetic pole of a rotor of the electric motor, based on the stator current and the stator voltage;
counting output pulses of the incremental encoder to obtain an encoder pulse count;
determining a position error of the rotor of said electric motor, based on the determined magnetic pole position and the counted encoder pulses;
correcting the counted encoder pulses based on the determined position error to obtain a corrected encoder pulse count; and
comparing the corrected encoder pulse count with the pulses-per-rotation configuration value PPRconf to determine the pulses-per-rotation estimation value PPRest.

4. The method of claim 1 , wherein the acquiring, the deriving, and the determining are each executed subsequent to completion of a travelling event associated with the transportation device.

5. The method of claim 1 , wherein the generating the instance of maintenance information includes
collecting a plurality of pulses-per-rotation error values PPRerr in response to separate, respective one or more determination of the pulses-per-rotation error value PPRerr;
computing error statistics over a particular time interval based on the collected plurality of pulses-per-rotation error values PPRerr;
evaluating trend information based on the computed error statistics over a plurality of particular time intervals; and
generating the instance of maintenance information in response to a determination that the evaluated trend information meets a particular maintenance criterion.

6. The method of claim 5 , wherein the particular maintenance criterion is associated with advance indication of a failure or problem associated with the maintenance system, such that the evaluated trend information meets the particular maintenance criterion prior to occurrence of the failure or problem.

7. The method of claim 5 , wherein
the particular maintenance criterion is associated with a particular type of failure or problem associated with the maintenance system, and
the instance of maintenance information indicates the particular type of failure or problem.

8. The method of claim 5 , wherein the evaluating and the generating are both executed at a remote monitoring unit or a data analysis platform.

9. The method of claim 5 , wherein the collecting and the computing are both executed at a local control unit of the transportation device.

10. The method of claim 1 , wherein the instance of maintenance information is transferred or made accessible to a remote maintenance center, a mobile service unit, or a local control unit of an elevator system, depending on a type of failure or problem indicated by the instance of maintenance information.

11. The method of claim 1 , wherein
the electric motor is a permanent magnet synchronous motor with a plurality of phases,
the electric motor is configured to be controlled by a frequency converter, and
the motor model provides two-component reference values for stator voltages and/or stator currents of the electric motor.

12. The method of claim 1 , wherein
the transportation device is selected from one of
an elevator,
an escalator,
a moving walkway,
a cable car,
a railway locomotive,
a railcar,
a roller coaster,
a conveyor,
a crane,
a positioning unit, and
a combination thereof.

13. A non-transitory data carrier carrying data representing a software program that, when executed on a computer, realizes the method according to claim 1 .

14. The non-transitory data carrier of claim 13 , wherein the computer is a distributed computing system part of a cloud computing system.

15. A controller configured to control a transportation device, the transportation device configured to be propelled by an electric motor, the controller comprising:
a non-transitory data carrier carrying data representing a software program; and
a computer configured to execute the software program to
receive an output of an incremental encoder, the incremental encoder configured to sense motion of a moving part of the electric motor or a part configured to be moved by the electric motor;
calculate a motor model associated with control of the electric motor;
acquire a pulses-per-rotation configuration value (PPRconf), the pulses-per-rotation configuration value PPRconf being a drive parameter of the incremental encoder and representing a nominal/configured quantity of pulses which should be provided by the incremental encoder per one rotation of the electric motor when the incremental encoder is operating according to normal operation;

derive a pulses-per-rotation estimation value (PPRest), the pulses-per-rotation estimation value PPRest representing an estimated quantity of pulses actually provided by the incremental encoder per one r

Assignees

• Kone Corp

Inventors

• Mustonen Matti
• Laaksonheimo Jyrki

Classifications

• B66B5/0025 Primary

  for maintenance or repair · CPC title

• G05B2219/24215

  Scada supervisory control and data acquisition · CPC title

• G01R31/007

  using microprocessors or computers · CPC title

• G07C5/085

  using electronic data carriers · CPC title

• G05B19/0423

  Input/output · CPC title