Method and device for processing measurement signals from a movement sensor on board a motor vehicle

• US 20060080006A1
• Filed: 10/12/2005
• Published: 04/13/2006
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Continental Automotive Systems US Incorporated (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Bidou, Patrick, Fonzes, Georges
• Granted Patent: US 7,463,952 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: B60W 40/107 Longitudinal acceleration
• CPC Class Codes: B60W 40/12 related to parameters of the vehicle itself , e.g. tyre models
• CPC Class Codes: F16H 2059/446 Detecting vehicle stop, i.e. the vehicle is at stand still, e.g. for engaging parking lock
• CPC Class Codes: F16H 59/44 dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: G01P 21/02 of speedometers

Abstract

A method of processing measurement signals from a movement sensor on board a motor vehicle, wherein in a preliminary phase, a reference offset value is stored, representative of the value of the signal output by the sensor, with the vehicle stopped, a noise value representative of the white noise of the sensor, and an acceleration value determining a running threshold of the vehicle. Then, throughout the life of the vehicle, sequences of successive measurements are taken of the value of the signal output by the sensor, and, for each sequence, the stored offset value is subtracted from each measure value and each calculated value is compared with the stored running threshold. Information representative of a stopped state is transmitted only if, the calculated values are less than the stored running threshold and roughly equal to each other with a tolerance margin corresponding to the stored noise value.

Claims

1. A method of processing measurement signals from a movement sensor (2) on board a motor vehicle, characterized in that:

in a preliminary phase;

the value (AcOFF) of the signal output by the movement sensor (2) is measured, with the vehicle stopped, and said measured value is stored as a reference value, called an offset value,

an acceleration value (Sa) determining a running threshold of the motor vehicle is fixed and stored,

a so-called noise value (Bb) is stored, characteristic of the operation of the movement sensor (2), and representative of the white noise of the latter,

then, throughout the life of the vehicle, sequences of n successive measurements of the value of the signal output by the movement sensor (2) are carried out, and for each of these sequences, the stored offset value is subtracted from each of the n measured values and each of the duly calculated values is compared with the stored running threshold, and information representative of a stopped state of the vehicle is transmitted if, and only if, the n calculated values are all less than the stored running threshold and roughly equal to each other with a tolerance margin corresponding to the stored noise value.

2. The processing method as claimed in claim 1, characterized in that, following each sequence of n measurements giving rise to vehicle stopped information, a new offset value according to the n measured values of said sequence of n measurements is substituted for the stored offset value.

3. The processing method as claimed in claim 2, characterized in that, following each sequence of n measurements giving rise to vehicle stopped information, a so-called sequence value is determined, representative of the n measured values of said sequence of measurements, this sequence value is compared with the stored offset value, and the following is fixed as the new offset value that is stored:

the stored offset value added to a predetermined correction coefficient if the sequence value is greater than the stored offset value,

and the stored offset value subtracted from a predetermined correction coefficient if the sequence value is less than the stored offset value.

4. The processing method as claimed in claim 3, characterized in that the value of the correction coefficient is fixed at 0.5.

5. The processing method as claimed in claim 3, characterized in that the first measured value of the corresponding sequence of n measurements is fixed as the value of a sequence.

6. The processing method as claimed in claim 1, characterized in that each sequence of measurements consists in measuring successively, with an interval roughly between 10 seconds and 60 seconds, n values of the signal output by the movement sensor (2).

7. The processing method as claimed in claim 1, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

9. The processing method as claimed in claim 4, characterized in that the first measured value of the corresponding sequence of n measurements is fixed as the value of a sequence.

10. The processing method as claimed in claim 2, characterized in that each sequence of measurements consists in measuring successively, with an interval roughly between 10 seconds and 60 seconds, n values of the signal output by the movement sensor (2).

11. The processing method as claimed in claim 3, characterized in that each sequence of measurements consists in measuring successively, with an interval roughly between 10 seconds and 60 seconds, n values of the signal output by the movement sensor (2).

12. The processing method as claimed in claim 4, characterized in that each sequence of measurements consists in measuring successively, with an interval roughly between 10 seconds and 60 seconds, n values of the signal output by the movement sensor (2).

13. The processing method as claimed in claim 5, characterized in that each sequence of measurements consists in measuring successively, with an interval roughly between 10 seconds and 60 seconds, n values of the signal output by the movement sensor (2).

14. The processing method as claimed in claim 2, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

15. The processing method as claimed in claim 3, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

16. The processing method as claimed in claim 4, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

17. The processing method as claimed in claim 5, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

18. The processing method as claimed in claim 6, characterized in that each sequence of measurements consists in performing n=5 successive measurements of the value of the signal output by the movement sensor (2).

8. A device for processing measurement signals from a movement sensor (2) on board a motor vehicle, characterized in that it comprises, in combination:

means (3) of measuring the values of the signals (AcB) output by the movement sensor (2),

means (4) of storing a reference value (AcOFF), called an offset value, representative of the value of the signal output by the movement sensor (2), with the vehicle stopped, a so-called noise value (Bb), characteristic of the operation of the movement sensor, and representative of the white noise of the latter, and an acceleration value (Sa) determining a running threshold of the motor vehicle,

and a computation unit (5) connected to the measurement means (3) and to the storage means (4), and programmed, throughout the life of the vehicle, to command sequences of n successive measurements of the value of the signal output by the movement sensor (2), and, for each of these sequences, to subtract the stored offset value from each of the n measured values and compare each of the duly calculated values with the stored running threshold, and to command the transmission of information representative of a stopped state of the vehicle if, and only if, the n calculated values are all less than the stored running threshold and roughly equal to each other with a tolerance margin corresponding to the stored noise value.