Method, selector switch and selector device for securely sensing a selector switch position

• US 6,469,642 B1
• Filed: 11/12/1999
• Issued: 10/22/2002
• Est. Priority Date: 11/12/1998
• Status: Expired due to Term

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Kreppold, Bernhard
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US09/438,393
• Time in Patent Office: 1,075 Days
• Field of Search: 341/20, 341/9, 341/15, 341/7, 341/2, 341/10, 341/13, 341/8, 307/10.1, 200/6.A
• US Class Current: 341/20
• CPC Class Codes: F16H 2061/122 Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 59/105 consisting of electrical switches or sensors
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures

Abstract

A method, a selector switch and selector device, is provided for secure position detection of a selector switch, which can be operated in at least two positions, particularly in a vehicle. In the method, a code word composed of a data part and a test part is assigned to each selector switch position. The code word is generated in each selector switch position by a number of switches corresponding to the number of bits of the code word. The data part already indicates an unambiguous selector switch position. In each code word, the test part is determined corresponding to a defined imaging rule from the data part. The test part generated by the switches is compared with the test part formed on the basis of the imaging rule from the data part, and, from a comparison of the two test parts, a conclusion is drawn with respect to a correct or erroneous position detection of the selector switch.

Claims

1. Method for secure position detection of a selector switch in a vehicle, which is operable in at least two positions, the method comprising the acts of:

assigning a first switch position code composed of at least two bits to each selector switch position;

assigning a second switch position code that is a coded function of the first switch position code for each selector switch position;

generating a code word by a number of switches corresponding to the number of bits of the code word, which code word comprises the first and second position code for each selector switch position;

using a decoding algorithm, which corresponds to the coded function, to determine a decoded second switch position code; and

drawing a conclusion with respect to a correct or erroneous position detection of the selector switch from a comparison of the code word and the decoded second position code.

8. Method according to claim 1, wherein the code words are assigned to the switching positions of the selector switch such that, in the case of each switching operation, a certain number of bits of the code word will change.

10. Method according to claim 8, wherein 4 bits of the code word change.

12. Method according to claim 1, wherein the data part comprises 3 bits.

14. Method according to claim 1, wherein the second switch position code as a test part comprises 3 bits.

17. Method according to claim 1, wherein, during the comparison of the detected and the calculated second switch position code as au test part, a syndrome (F) is formed as an EXCLUSIVE-OR linkage of both test parts.

2. Method for secure position detection of a selector switch in a vehicle, which is operable in at least two positions, the method comprising the acts of:

assigning a code word composed of at least two bits to each selector switch position;

generating the code word by a number of switches, which correspond to the number of bits of the code word, wherein the code word includes a first switch position code for the selector switch position and a coded function of the first switch position code, the coded function being an imaging rule;

using the imaging rule, calculating the coded function of the first switch position code for the selector switch position from the code word; and

drawing a conclusion with respect to a correct or erroneous position detection of the selector switch from a comparison of the code word and the calculated coded function of the first switch position code obtained using the imaging rule.

3. Method according to claim 2, wherein:

each code word comprises a data part as the first switch position code and a test part as the coded function of the first switch position code, the data part already indicating an unambiguous selector switch position;

for each code word, the test part is determined corresponding to the defined imaging rule from the data part;

the test part generated by the switches is compared with the test part formed from the data part on the basis of the imaging rule; and

from the comparison of the two test parts, a conclusion is drawn with respect to a correct or erroneous position detection of the selector switch.

4. Method according to claim 3, wherein for each code word, an expanded test part is provided whose information is obtained from a defined combination of the data and test parts.

5. Method according to claim 3, wherein the test part information is obtained by EXCLUSIVE-OR linkages of data part information.

6. Method according to claim 4, wherein the test part information is obtained by EXCLUSIVE-OR linkages of data part information.

7. Method according to claim 2, wherein the code words and the imaging rule for a test part as the first switch position code are formed such that a single error is detectable in the test or a data part as the coded function, is correctly assignable and is eliminatable.

9. Method according to claim 2, wherein the code words are assigned to the switching positions of the selector switch such that, in the case of each switching operation, a certain number of bits of the code word will change.

11. Method according to claim 9, wherein 4 bits of the code word change.

13. Method according to claim 2, wherein the first switch position code as a data part comprises 3 bits.

15. Method according to claim 2, wherein the coded function of the first switch position code forms a test part comprised of 3 bits.

16. Method according to claim 4, wherein the expanded test part comprises 1 bit.

18. Method according to claim 2, wherein, during the comparison of the detected and the calculated coded function of the first switch position code as a test part, a syndrome (F) is formed as an EXCLUSIVE-OR linkage of both test parts.

19. Method according to claim 7, wherein, in the event of a single error in the data part, a. syndrome table supplies information concerning the position of the error.

20. Method according to claim 4, wherein another table is stored by which, while taking into account the expanded test part and the comparison of the test parts, particularly taking into account the syndrome, information can be obtained concerning a single error or a double error.

21. A selector switch for a motor vehicle, comprising:

a defined number of switches, said defined number of switches electrically detecting selector switch positions of the selector switch; and

wherein said switches supply information assigned to a respective selector switch position and combined to a respectively assigned code word, the code word containing the selector switch position and a coded function of the selector switch position.

22. Selector switch according to claim 21, wherein each code word comprises a data part and a test part, the selector switch position being detectable already from the data part, and wherein the switches for the test part are set up such that, at each selector switch position, the test part is obtained corresponding to the coded function as a defined imaging rule from the data part.

23. Selector switch according to claim 21, wherein sliding contacts are used as the switches.

24. Selector switch according to claim 22, wherein sliding contacts are used as the switches.

25. Selector switch according to claim 21, wherein magnetic Hall sensors are used as the switches.

26. Selector switch according to claim 22, wherein magnetic Hall sensors are used as the switches.

27. Selector switch according to claim 21, wherein the switches are arranged such that, during a switching operation, the code word changes by a certain number of switch operations.

28. Selector switch according to claim 21, wherein for each switch, Hall sensor magnets are arranged corresponding to a desired shifting gate and corresponding to an assignment of the code word information/selector switch position.

29. Selector switch according to claim 28, wherein all of said Hall sensor magnets are arranged in a matching magnet array.

30. Selector switch according to claim 21, wherein the selector switch is one of a toggle switch, rocker switch, push button switch, and lever.

31. A selecting device for a vehicle, comprising:

a selector switch, in which selector switch positions are electrically detectable via a defined number of switches, said switches supplying information assigned to a respective selector switch position and combined to a respectively assigned code word, the code word containing the selector switch position and a coded function of the selector switch position;

a control device, said code word being supplied to the control device and, in accordance with a reported and tested selector switch position, supplying a corresponding signal to a unit to be controlled.