Device for monitoring at least one parameter for a plurality of vehicle wheels

• US 20030020604A1
• Filed: 07/24/2002
• Published: 01/30/2003
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Fischer, Martin, Prenninger, Martin, Fussel, Dominik
• Granted Patent: US 6,690,271 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0437 Means for detecting electromagnetic field changes not being part of the signal transmission per se, e.g. strength, direction, propagation or masking

Abstract

A device for monitoring at least one parameter for vehicle wheels includes, on each wheel, a detector unit having a transmitter unit that respectively transmits a phase-modulated or frequency-modulated signal to a central evaluation and control unit. Each detector unit transmits, at specific time intervals, a brief signal that contains a uniquely defined identifier. After a wheel is changed, a renewed assignment of the detector unit to the respective wheel positions can be carried out in an assignment mode of the detector unit and of the control unit, by registering a profile of the mean reception power for each detector unit as a function of the angular position of the respective wheel and comparing such signature profile with stored signature information. The comparison can be carried out by cross-correlating the two respectively decisive curves, or by comparing individual values or specific characteristic variables of the profiles.

Claims

1. A device for monitoring vehicle wheels, comprising:

detector units disposed at the wheels, each detector unit having;

a sensor for registering at least one parameter of a wheel; and

a transmitter unit transmitting information regarding the at least one parameter, each of said detector units transmitting, with said transmitter unit, the information in a modulated signal over a wireless transmission path;

a central evaluation and control unit having a receiver unit receiving the information from said transmitter unit and demodulating the signal, said control unit evaluating the information from said detector units, and generating signals dependent thereon;

said control unit having a normal operating mode and an assignment mode and;

in said normal operating mode;

each detector unit transmitting, as the information, an information item relating to the registered parameter and a wheel identifier uniquely defined for each of the wheels; and

said control unit;

evaluating the wheel identifier and the information relating to the registered parameter-from the signal demodulated by said receiver unit; and

assigning a wheel position to each information item relating to the registered parameter from the identifier and from a stored assignment information item;

in said assignment mode;

each said transmitter unit transmitting, as the information, at least the wheel identifier;

said receiver unit generating a signature signal representing a measure for an average signal power of the received modulated signal;

a duration of the signal transmitted by said transmitter unit of said detector units being shorter in comparison with a time required for a complete revolution of a wheel at a maximum speed of the wheel;

said control unit registering said signature signal derived from each received signal and assigning an angle information item to the respective value of said signature signal;

said control unit acquiring the angle information item from one of;

a time interval between one of;

said signature signals; and

said signature signals and a fixed time; and

the group consisting of;

a velocity of the vehicle;

a parameter proportional to the velocity of the vehicle; and

an angle information item relating to an angular position of the respective wheel fed to said control unit; and

said control unit assigning to said wheel position said wheel identifier transmitted by each of said detector units by comparing one of registered values and an information item determined therefrom with a stored signature information characteristic of each said wheel position, and storing the angle information item as an assignment information item.

2. The device according to claim 1, wherein the modulated signal is one of a phase-modulated signal and a frequency-modulated signal.

3. The device according to claim 1, wherein said stored signature information is one of:

a characteristic profile formed from values of said signature signal acquired in a predetermined fashion in a reference mode at a plurality of angular positions, a first partial information item being made dependent on a second partial information item; and

at least one characteristic variable of said characteristic profile.

4. The device according to claim 3, wherein said stored signature information is a characteristic profile of said signature signal as a function of one of an angular position and a variable connected thereto.

5. The device according to claim 4, wherein an angular range is one revolution of a wheel.

6. The device according to claim 3, wherein said stored signature information is histogram information, a number of registered values of said signature signal occurring in respectively substantially constant sections of a value range for said signature signal being stored for a predefined number of registered signature signal values.

7. The device according to claim 3, wherein said control unit:

determines at least one characteristic variable of a profile formed from a plurality of signature signal values registered at specific angular positions of a respective one of the wheels; and

compares said at least one characteristic variable with one of corresponding stored characteristic variables and characteristic variables determined from corresponding stored profiles.

8. The device according to claim 3, wherein said at least one characteristic variable is selected from the group consisting of:

a mean value of said signature information;

a standard deviation of values of said profile formed from said signature signal of said signature information;

a maximum difference between values of said profile formed from said signature signal of said signature information; and

said profile of said signature information.

9. The device according to claim 3, wherein said at least one characteristic variable is selected from the group consisting of:

a mean value of said signature information;

a standard deviation of values of said profile formed from said signature signal of said signature information;

a maximum difference between values of said profile formed from said signature signal of said signature information; and

said profile of said signature information.

10. The device according to claim 3, wherein said control unit cross-correlates said profile determined from said signature signal with said stored signature profiles and one of:

excludes wheel positions assigned to ones of said signature profiles at which a correlation coefficient is smaller than a predefined limit; and

assigns wheel positions associated with ones of said signature profiles at which a correlation coefficient is greater than a predefined limit.

11. The device according to claim 1, wherein said control unit automatically switches over into said assignment mode if no revolution of a wheel is detected for a time period longer than a predefined value.

12. The device according to claim 1, including an acceleration sensor, said control unit automatically switching over into said assignment mode if said acceleration sensor detects no revolution of a wheel for a time period longer than a predefined value.

13. The device according to claim 1, wherein said control unit has a reference mode in which:

said control unit acquires said signature information by evaluating and storing said signals transmitted by said detector unit; and

said control unit is informed of an assignment of a signature profile to a respective said wheel position through one of externally supplied signals and externally supplied data inputs.

14. The device according to claim 1, wherein:

said evaluation and control unit is an input, evaluation, and control unit;

said input, evaluation, and control unit has a reference mode in which;

said input, evaluation, and control unit acquires said signature information by evaluating and storing said signals transmitted by said detector unit; and

said input, evaluation, and control unit is informed of an assignment of a signature profile to a respective said wheel position through one of externally supplied signals and externally supplied data inputs.