System and method for improving travel across joints in a track for a linear motion system

Patent metadata

Field	Value
Publication number	US-11027615-B2
Application number	US-201816203922-A
Country	US
Kind code	B2
Filing date	Nov 29, 2018
Priority date	Nov 29, 2018
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A system for determining the position of a mover as the mover transitions between segments along a track includes a first controller on a first track segment and a second controller on a second track segment. The first and second track segments are adjacent to each other and a junction is located between the two segments. The first and second controllers are in communication with each other and share a locally determined position value with the other controller. Each controller determines a compensated position value as a function of both a locally determined position value and the shared position value received from the other controller. Each controller utilizes the compensated value of the position value as determined on that controller to control operation of the mover while it is present on the corresponding track segment.

First claim

I claim:

1. A system for improving motion of movers across junctions in a linear drive system, the system comprising:
a plurality of movers; and
a track along which the plurality of movers travel, the track including at least a first track segment and a second track segment, wherein:
the first track segment includes:
a first segment controller operative to control operation of each of the plurality of movers on the first track segment, and
at least one first position sensor operative to detect a location of each of the plurality of movers on the first track segment;

the second track segment includes:
a second segment controller operative to control operation of each of the plurality of movers on the second track segment, and
at least one second position sensor operative to detect a location of each of the plurality of movers on the second track segment;

the first segment controller is in communication with the second segment controller;
a junction is defined between the first track segment and the second track segment; and
when a first mover, selected from the plurality of movers, crosses the junction between the first track segment and the second track segment, the first segment controller is operative to determine a first measured position of the first mover with the location from the at least one first position sensor, transmit a first shared position to the second segment controller, receive a second shared position from the second segment controller, and determine a first compensated position of the first mover as a function of the first measured position and the second shared position and the second segment controller is operative to determine a second measured position of the first mover with the location from the at least one second position sensor, transmit the second shared position to the first segment controller, receive the first shared position from the first segment controller, and determine a second compensated position of the first mover as a function of the first shared position and the second measured position.

2. The system of claim 1 wherein the first shared position is the first measured position and the second shared position is the second measured position.

3. The system of claim 2 wherein the first compensated position and the second compensated position are each equal to an average of the first measured position and the second measured position.

4. The system of claim 2 wherein:
the first track segment includes a first end and a second end,
the second track segment includes a first end and a second end,
the second end of the first track segment is adjacent to the first end of the second track segment and the junction is located between the second end of the first track segment and the first end of the second track segment, and
a compensation region spans the junction and includes a starting point and an ending point, wherein the starting point is spaced inward along the first track segment from the second end of the first track segment and the ending point is spaced inward along the second track segment from the first end of the second track segment.

5. The system of claim 4 wherein:
at least one of the first segment controller and the second segment controller is operative to determine a center-line distance of the mover,
the center-line distance is equal to a distance between a center axis of the mover and the starting point of the compensation region, and
the first compensated position and the second compensated position are determined as a function of the first measured position, the second measured position, a width of the compensation region, and the center-line distance.

6. The system of claim 1 wherein the first shared position is the first compensated position and the second shared position is the second compensated position.

7. The system of claim 6 wherein the first compensated position is an average of the first measured position and the second compensated position and the second compensated position is an average of the first compensated position and the second measured position.

8. The system of claim 6 wherein:
the first track segment includes a first end and a second end,
the second track segment includes a first end and a second end,
the second end of the first track segment is adjacent to the first end of the second track segment and the junction is located between the second end of the first track segment and the first end of the second track segment, and
a compensation region spans the junction and includes a starting point and an ending point, wherein the starting point is spaced inward along the first track segment from the second end of the first track segment and the ending point is spaced inward along the second track segment from the first end of the second track segment.

9. The system of claim 8 wherein:
at least one of the first segment controller and the second segment controller is operative to determine a center-line distance of the mover,
the center-line distance is equal to a distance between a center axis of the mover and the starting point of the compensation region,
the first compensated position is determined as a function of the first measured position, the second compensated position, a width of the compensation region, and the center-line distance, and
the second compensated position is determined as a function of the first compensated position, the second measured position, the width of the compensation region, and the center-line distance.

10. The system of claim 1 wherein:
the at least one first position sensor and the at least one second position sensor are each a magnetic field detector,
each of the plurality of movers includes an array of magnets spaced along a length of the mover, wherein at least one first magnet from the array of magnets is present on the first segment and at least one second magnet from the array of magnets is present on the second segment as the first mover crosses the junction,
the at least one first position sensor detects the location of the first mover by generating a signal corresponding to a distance that the at least one first magnet is away from the at least one first position sensor, and
the at least one second position sensor detects the location of the first mover by generating a signal corresponding to a distance that the at least one second magnet is away from the at least one second position sensor.

11. A method for improving motion of movers across junctions in a linear drive system, the method comprising the steps of:
receiving a first position feedback signal with a first controller from a first position sensor on a first track segment, wherein the first position feedback signal corresponds to a position of a mover traveling across a junction between the first track segment and a second track segment in the linear drive system;
determining a first measured position of the mover with the first controller as a function of the first position feedback signal;
receiving a second position feedback signal with a second controller from a second position sensor on the second track segment;
determining a second measured position of the mover with the second controller as a function of the second position feedback signal;
transmitting the first measured position from the first controller to the second controller;
transmitting the second measured position from the second controller to the first controller;
determining a first compensated position of the mover with the first controller as a function of the first measured position and the second measured position;
determining a second compensated position of the mover with the second controlle

Assignees

• Rockwell Automation Tech Inc

Inventors

• Huang Yuhong

Classifications

• B60L15/005

  for control of propulsion for vehicles propelled by linear motors · CPC title

• B60L13/03 Primary

  Electric propulsion by linear motors · CPC title

• Y02T90/16

  Information or communication technologies improving the operation of electric vehicles · CPC title

• B60L13/10 Primary

  Combination of electric propulsion and magnetic suspension or levitation · CPC title

• B60L2200/26

  Rail vehicles · CPC title