System and method for determining information related to a rotation of a shaft

Patent metadata

Field	Value
Publication number	US-9765711-B2
Application number	US-201514722206-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	May 27, 2015
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A system and method for determining information related to a rotation of a shaft. The method includes receiving a signal associated with a plurality of targets and gaps passing by a sensor. The targets and gaps are positioned around a circumference of a wheel that is fixed for rotation with the shaft. The method includes forming a sensed target-and-gap sequence based on the signal, wherein the sensed target-and-gap sequence represents a subset of the targets and gaps. The method further includes comparing the sensed target-and-gap sequence to a set of known target-and-gap sequences stored in memory. Each known target-and-gap sequence is associated with a respective known circumferential portion of the wheel. The method also includes determining which respective, known target-and-gap sequence is identical to the sensed target-and-gap sequence.

First claim

What is claimed is:

1. A method for determining information related to a rotation of a shaft, the method comprising:
receiving a signal associated with a plurality of targets and gaps passing by a sensor, the targets and gaps being positioned around a circumference of a wheel that is fixed for rotation with the shaft, the gaps being positioned between the targets;
forming a sensed target-and-gap sequence based on the signal, the sensed target-and-gap sequence representing a subset of the targets and gaps, all of the gaps having identical angular widths;
comparing the sensed target-and-gap sequence to a set of known target-and-gap sequences stored in memory, each known target-and-gap sequence being associated with a respective, known circumferential portion of the wheel;
determining which respective known target-and-gap sequence is identical to the sensed target-and-gap sequence;
determining an angular position of the shaft at a given time based on which known target-and-gap sequence is identical to the sensed target-and-gap sequence;
injecting fuel based on the angular position of the shaft at the given time;
receiving a verification signal associated with a verifier passing by the sensor, the verifier indicating either a target or a gap of the target and gaps;
adding the verifier as an additional value to an end of the sensed target-and-gap sequence based on the verification signal; and
comparing the verifier to an expected verifier, the expected verifier being stored in memory and expected to follow the sensed target-and-gap.

2. The method of claim 1 , wherein the forming comprises forming the sensed target-and-gap sequence out of numbers.

3. The method of claim 1 , comprising:
forming a new, sensed target-and-gap sequence if the verifier does not match the expected verifier;
comparing the new, sensed target-and-gap sequence to the set of known target-and-gap sequences; and
determining which known target-and-gap sequence is identical to the new, sensed target-and-gap sequence.

4. The method of claim 3 , comprising confirming an angular position of the shaft based on which known target-and-gap sequence is identical to the new, sensed target-and-gap sequence.

5. The method of claim 1 , comprising assigning a target time stamp to each target in the target-and-gap sequence, each target time stamp representing when each respective target is sensed.

6. The method of claim 5 , comprising determining an angular velocity of the shaft, at a given time, based on the target time stamps.

7. The method of claim 5 , comprising determining the angular position of the shaft, at a given time, based on:
the target time stamps; and
the determination of which known target-and-gap sequence is identical to the sensed target-and-gap sequence.

8. A system for determining information related to a rotation of a shaft, the system comprising:
a wheel fixed for rotation with the shaft, the wheel comprising a plurality of targets and a plurality of gaps positioned sporadically therebetween, the targets and gaps being positioned about a circumference of the wheel, all of the targets having identical angular widths;
a sensor positioned adjacent to the wheel; and
a controller coupled to the sensor, the controller configured to:
receive a signal from the sensor, the signal being associated with the plurality of targets and gaps passing by the sensor;
form a sensed target-and-gap sequence as each target-and-gap is sensed, the sensed target-and-gap sequence being a subset of the targets and the gaps;
compare the sensed target-and-gap sequence to a set of known target-and-gap sequences stored in memory, each known target-and-gap sequence being associated with a known circumferential portion of the wheel;
determine which respective known target-and-gap sequence is identical to the sensed target-and-gap sequence;
determine an angular position of the shaft at a given time based on which known target-and-gap sequence is identical to the sensed target-and-gap sequence; and
inject fuel based on the angular position of the shaft at the given time.

9. The system of claim 8 , wherein the targets of the target-and-gap sequence are in immediate and consecutive sequence with both sides of all of the gaps of the target-and-gap sequence, and all of the gaps have identical angular widths.

10. The system of claim 8 , wherein all of the targets are identical to one another.

11. The system of claim 8 , wherein all of the gaps have identical angular widths.

12. The system of claim 8 , wherein a total number of known target-and-gap sequences is equivalent to a total sum of the targets and gaps.

13. The system of claim 8 , wherein each known target-and-gap sequence is a unique sequence, and a length of each known target-and-gap sequence is a mathematically minimum length for a sum of the targets and gaps.

14. The system of claim 8 , wherein the controller is configured to form the sensed target-and-gap sequence out of numbers.

15. The system of claim 8 , wherein the controller is configured to:
receive a verification signal from the sensor, the verification signal is associated with a verifier that is immediately following the sensed target-and-gap sequence and that indicates either a verifying target or a verifying gap;
add the verifier as an additional value to an end of the sensed target-and-gap sequence based on the verification signal; and
compare the verifier to an expected verifier, the expected verifier is based on a known verifier that is stored in memory and that is expected to follow the sensed target-and-gap sequence.

16. The system of claim 15 , wherein the controller is configured to:
form a new, sensed target-and-gap sequence if the verifier does not match the expected verifier;
compare the new, sensed target-and-gap sequence to the set of known target-and-gap sequences stored in memory;
determine which respective known target-and-gap sequence is identical to the new, sensed target-and-gap sequence; and
confirm information related to the rotation of the shaft if the verifier matches the expected verifier.

17. The system of claim 16 , wherein the controller is configured to assign a target time stamp to each target in the target-and-gap sequence.

18. The system of claim 17 , wherein the controller is configured to determine an angular velocity of the shaft, at a given time, based on the target time stamps.

19. The system of claim 17 , wherein the controller is configured to determine the angular position of the shaft, at a given time, based on:
the target time stamps; and
the determination of which known target-and-gap sequence is identical to the sensed target-and-gap sequence.

Assignees

• Deere & Co

Inventors

• Martinson Peter D

Classifications

• G01D5/12

  using electric or magnetic means (G01D5/06 takes precedence) · CPC title

• G01D5/2455 Primary

  with incremental and absolute tracks on the same encoder · CPC title

• G01D5/26

  characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light · CPC title

• F02D41/3005

  Details not otherwise provided for · CPC title

• G01D5/2492

  Pulse stream · CPC title