Steering Angle Sensor with Functional Security

Patent metadata

Field	Value
Publication number	US-2018259367-A1
Application number	US-201615760541-A
Country	US
Kind code	A1
Filing date	Sep 1, 2016
Priority date	Sep 17, 2015
Publication date	Sep 13, 2018
Grant date	—

Abstract

The invention relates to a method for identifying a fault ( 96 ) in an angle sensor ( 24 ) which is designed to determine the angular position ( 18 ) of a shaft ( 14 ) based on an angular position difference ( 56 ) between a first output gear ( 32 ), which is driven by the shaft ( 14 ), and a second output gear ( 34 ), which is driven by the shaft ( 14 ), the output gears differing in respect of their diameter ( 34, 36 ), said method comprising:
determining a reference value ( 18, 52 ) for the angular position ( 18 ) of the shaft ( 14 ) based on the angular position ( 42 ) of the first output gear ( 32 ), determining a comparison value ( 18′, 52′ ) for the angular position ( 18 ) of the shaft ( 14 ) based on the angular position ( 46 ) of the second output gear ( 34 ) and a transmission ratio ( 90 ) between the first output gear ( 32 ) and the second output gear ( 34 ), and identifying the fault ( 96 ) when a comparison ( 93, 94 ) of the reference value ( 18, 52 ) and the comparison value ( 18′, 52′ ) satisfies a predetermined condition ( 95 ).

First claim

1 . A method for identifying a fault in an angle sensor which is designed to determine the angular position of a shaft based on an angular position difference between a first output gear, which is driven by the shaft, and a second output gear, which is driven by the shaft, the output gears differing in respect of their diameter, said method comprising:
determining a reference value for the angular position of the shaft based on the angular position of the first output gear, determining a comparison value for the angular position of the shaft based on the angular position of the second output gear and a transmission ratio between the first output gear and the second output gear, and identifying the fault when a comparison of the reference value and the comparison value satisfies a predetermined condition.

2 . The method as claimed in claim 1 , wherein, in order to determine the reference value, a round count value, which is determined on the basis of the angular position difference, for the first output gear and the angular position of the first output gear are added together.

3 . The method as claimed in claim 1 , wherein, in order to determine the comparison value, a redundant reference value is generated from a sum of a round count value, which is determined on the basis of the angular position differences, for the second output gear and the angular position of the second output gear through weighting with the transmission ratio.

4 . The method as claimed in claim 1 , wherein the comparison comprises the formation of a difference between the reference value and the comparison value, and wherein the predetermined condition is satisfied if the difference formed leaves a predetermined value range.

5 . The method as claimed in claim 4 , comprising saving the difference formed in a memory.

6 . The method as claimed in claim 5 , wherein the difference is only saved in the memory if a value of a difference stored in the memory is smaller than a value of the difference formed.

7 . The method as claimed in claim 1 , wherein the angular positions of the output gears are detected using magnetoresistive sensors, and wherein the fault in the angle sensor is further identified on the basis of an orthogonality of the output signals of the magnetoresistive sensors, which output signals describe the angular positions.

8 . A control device including a computer and for identifying a fault in an angle sensor which is designed to determine the angular position of a shaft based on an angular position difference between a first output gear, which is driven by the shaft, and a second output gear, which is driven by the shaft, the output gears differing in respect of their diameter, the computer configured to
determine a reference value for the angular position of the shaft based on the angular position of the first output gear, determine a comparison value for the angular position of the shaft based on the angular position of the second output gear and a transmission ratio between the first output gear and the second output gear, and identify the fault when a comparison of the reference value and the comparison value satisfies a predetermined condition.

9 . An angle sensor for determining the angular position of a shaft based on an angular position difference between a first output gear, which is driven by the shaft, and a second output gear, which is driven by the shaft, comprising the first output gear, the second output gear, which has a diameter that differs from a diameter of the first output gear, and a control device configured to
determine a reference value for the angular position of the shaft based on the angular position of the first output gear, determine a comparison value for the angular position of the shaft based on the angular position of the second output gear and a transmission ratio between the first output gear and the second output gear, and identify the fault when a comparison of the reference value and the comparison value satisfies a predetermined condition.

10 . A non-transitory computer-readable medium comprising programming instructions that, when executed on a computer cause the computer to
determine a reference value for the angular position of the shaft based on the angular position of the first output gear, determine a comparison value for the angular position of the shaft based on the angular position of the second output gear and a transmission ratio between the first output gear and the second output gear, and identify the fault when a comparison of the reference value and the comparison value satisfies a predetermined condition.

Assignees

• Bourns Inc

Inventors

• Klimenko Valeri

Classifications

• G01D5/24476 Primary

  Signal processing (G01D5/2448 - G01D5/24495 take precedence) · CPC title

• G01D5/2452

  incorporating two or more tracks having an (n, n+1, ...) relationship · CPC title

• G01D5/04

  using levers; using cams; using gearing · CPC title

• G01D2205/26

  Details of encoders or position sensors specially adapted to detect rotation beyond a full turn of 360°, e.g. multi-rotation · CPC title