Section based safety functions for independent cart applications

Patent metadata

Field	Value
Publication number	US-11186302-B2
Application number	US-201816188696-A
Country	US
Kind code	B2
Filing date	Nov 13, 2018
Priority date	Nov 13, 2018
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

An independent cart system with safety functions prevents unintended motion independently within different sections of the track while permitting motion along other sections of the track. A safety controller receives one or more input signals corresponding to operating conditions along the track. A safety program executing in the safety controller monitors the state of the input signals to determine whether a safety function is to be executed. When a safety program is executed, the safety controller transmits an output signal to one or more segment controllers present in one section along the track. Each segment controller is responsible for regulating current flow to the coils mounted to the corresponding track segment. In response to the signal from the safety controller, each segment controller in the section controls the power output to the coils along that section of track to achieve the safe operation desired in that segment.

First claim

We claim:

1. An independent cart system, comprising:
a track having a plurality of track segments, wherein each track segment includes;
a plurality of coils spaced along the track segment, and
a segment controller operative to regulate a current flow in the plurality of coils;

a plurality of movers, wherein each mover includes a set of drive magnets and each mover is configured to travel along the track responsive to an interaction between the set of drive magnets on the mover and an electromagnetic field generated by the current flow in the plurality of coils; and
a safety controller in communication with the segment controller in at least one of the plurality of track segments, the safety controller including at least one input configured to receive a safety configured to indicate the presence of a technician, wherein the safety controller is operative to:
receive the safety signal at the at least one input,
execute a safety program responsive to receiving the safety signal to achieve a desired safety level, and
transmit an output signal to the segment controller with which the safety controller is in communication responsive to executing the safety program, wherein the segment controller is operative to perform a safety function responsive to receiving the output signal from the safety controller.

2. The independent cart system of claim 1 , Wherein:
the track includes a plurality of sections defined along a length of the track,
each of the plurality of sections includes at least one track segment, and
the safety controller transmits the output signal to each segment controller within one of the plurality of sections responsive to receiving the safety signal.

3. The independent cart. system of claim 2 , wherein:
the safety controller receives a plurality of safety signals,
each of the plurality of safety signals corresponds to one of the plurality of sections,
the safety controller transmits a plurality of output signals,
each of the plurality of output signals is generated responsive to one of the plurality of safety signals, and
each of the plurality of output signals is transmitted to the section corresponding to the safety signal responsive to which it was generated.

4. The independent cart system of claim 2 , wherein the safety controller is further operative to:
receive a first safety signal and a second safety signal,
execute a first safety program responsive to the first safety signal,
execute a second safety program responsive to the second safety signal,
transmit a first output signal to the segment controller wherein the segment controller is operative to achieve a first safety function responsive to receiving the first output signal from the safety controller, and
transmit a second output signal to the segment controller wherein the segment controller is operative to achieve a second safety function responsive to receiving the second output signal from the safety controller.

5. The independent cart system of claim 2 . wherein:
the output signal is a first output signal,
the section receiving the first output signal is a first section, and
the safety controller is further operative to transmit at least one second output signal to each segment controller located in a second section, the second section being located adjacent to the first section.

6. The independent cart system of claim 5 wherein each segment controller in the second section is configured to execute a monitoring safety function responsive to receiving the second output signal from the safety controller.

7. The independent cart system of claim l wherein the segment controller receiving the output signal is operative to disable the current flow in the plurality of coils of the corresponding track segment.

8. A method for implementing a safety function in an independent cart system, wherein the independent cart system includes a track having a plurality of track segments and a plurality of movers configured to travel along the track, the method comprising the steps of:
regulating a current in a plurality of coils present along each track segment, selected from the plurality of track segments, with a segment controller corresponding to each track segment, wherein the current is regulated to control operation of each of the plurality movers present on the corresponding track segment;
receiving at a safety controller an input signal configured to indicate the presence of a technician. Wherein:
the input signal configured for operation at a desired safety level is required in at least one section of the track,
the track includes a plurality of sections defined along the track, and
at least one track segment is present in each of the plurality of sections;

executing a safety program in the safety controller responsive to receiving the input signal, wherein the safety program achieves the desired safety level;
transmitting an output signal from the safety controller to each segment controller corresponding to each track segment within the at least one section of the track in which safe operation is desired; and
executing a safety function with the segment controller in each track segment within the at least one section of the track in which safe operation is desired responsive to receiving the output signal at the corresponding segment controller.

9. The method of claim 8 further comprising the steps of:
receiving a plurality of input signals at the safety controller, wherein at least one of the plurality of input signals corresponds to each of the plurality of sections, and
transmitting a plurality of output signals from the safety controller, wherein each of the plurality of output signals is generated responsive to one of the plurality of input signals and wherein each of the plurality of output signals is transmitted to the section corresponding to the input signal responsive to which it was generated.

10. The method of claim 8 wherein the input signal is a first input signal, the safety program is a first safety program, and the output signal is a first output signal, the method further comprising the steps of:
receiving a second input signal at the safety controller, wherein the second input signal indicates safe operation is desired in at least one additional section of the track,
executing a second safety program in the safety controller responsive to receiving the second input signal;
transmitting a second output signal from the safety controller to each segment controller corresponding to each track segment within the at least one additional section of the track; and
executing a second safety function with the segment controller in each track segment within the at least one additional section of the track responsive to receiving the second output signal at the corresponding segment controller.

11. The method of claim 8 wherein the output signal is a first output signal, the section receiving the first output signal is a first section, and the method further comprises the step of transmitting at least one second output signal from the safety controller to each segment controller located in a second section, the second section being located adjacent to the first section.

12. The method of claim 11 further comprising the step of executing a monitoring safety function in each segment controller in the second section responsive to receiving the second output signal from the safety controller.

13. The method of claim 8 wherein executing the safety function includes disabling the current in each of the plurality of coils present along each track segment.

14. An independent cart system having a track with a p

Assignees

• Rockwell Automation Tech Inc

Inventors

• Desotelle Sawyer J
• Ozimek Patrick E
• Cooper Mark R
• Van Dorpe David D

Classifications

• Y02P90/02

  Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS] · CPC title

• B61L23/16 Primary

  Track circuits specially adapted for section blocking · CPC title

• B61L23/20

  with transmission of instructions to stations along the route · CPC title

• G05B2219/41337

  Linear drive motor, voice coil · CPC title

• G05B2219/40217

  Individual emergency stop lines for each part of system · CPC title