Method for determining spurious contacts on a contact detection sensor for a door handle of an automobile vehicle

• US 9,000,889 B2
• Filed: 08/09/2011
• Issued: 04/07/2015
• Est. Priority Date: 09/06/2010
• Status: Active Grant

• Current Assignee: Vitesco Technologies GmbH (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Continental Automotive France (Continental AG), Continental Automotive GmbH (Continental AG)
• Inventors: Baudru, Stephan, Cordier, Maxime, Elie, Olivier, Hourne, Xavier
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): AKKI, MUNEAR T
• Application Number:
  US13/818,471
• Publication Number:
  US 20130194069A1
• Time in Patent Office: 1,337 Days
• Field of Search: 340/5.72, 340/426.28, 340/562, 340/522, 340/501, 324/679
• US Class Current: 340/5.72
• CPC Class Codes: B60R 25/20 Means to switch the anti-theft system on or off
• CPC Class Codes: E05B 81/77 comprising sensors detecting the presence of the hand of a user
• CPC Class Codes: G07C 2209/65 using means for sensing the user's hand
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 19/00369 Modifications for compensating variations of temperature, supply voltage or other physical parameters
• CPC Class Codes: H03K 2217/94031 Calibration involving digital processing
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

Method for determining spurious contacts on a contact detection sensor for a handle of an automobile door, the sensor defining a locking area and being connected to an onboard electronic locking and unlocking system, includes:

• • a) detecting a contact on the locking area when, for an engagement time of the locking mechanism, the number of charge transfers from the sensor is less than a threshold number of charge transfers,
  • b) evaluating the number of charge transfers, starting from the time of the minimum value of the number of measured charge transfers and for an evaluation time in order to distinguish detections of contacts made by the user from detections of spurious contacts,
  • c) if the contact detections are spurious, matching the threshold number of charge transfers in order to be able to detect any next contact originating from the user on the locking area in the presence of spurious contacts.

Claims

1. A method for determining spurious contacts on a contact detection sensor (4) for a handle (3) of a door (2) of an automobile vehicle (1), said detection sensor (4) defining a locking control area (L) and being connected to an onboard electronic locking and unlocking system (6), said method comprising:

a) the detection of a contact on the locking area (L) of the detection sensor (4), when, for an engagement time (t₁, t₂) of the locking mechanism, the number of charge transfers (N) from the detection sensor (4) is less than a threshold number of charge transfers (N_th),

characterized in that the method furthermore comprises the following steps;

b) evaluation of the number of charge transfers (N_D′

), starting from the time of the minimum value (t<sub>D′

MIN</sub>) of the number of measured charge transfers and for an evaluation time (t) in order to distinguish the detections of contacts made by the user from the detections of spurious contacts,

c) if the contact detections are spurious contact detections, matching of the threshold number of charge transfers (N<sub>D′

th</sub>) in order to be able to detect any next contact originating from the user on the locking area (L) in the presence of spurious contacts.

2. The method for determining spurious contacts as claimed in claim 1, characterized in that, during the step b, the evaluation of the number of charge transfers (N_D′

)is carried out in the following manner;

recording of the minimum value of the number of charge transfers (N<sub>D′

MIN</sub>) reached during the contact detection and of the time corresponding to this value (t<sub>D′

MIN</sub>),

starting from this time (t<sub>D′

MIN</sub>), calculation of the average of the number of charge transfers (N<sub>D′

MOY</sub>) over an evaluation period of time (t),

comparison between the minimum value of the number of recorded charge transfers (N<sub>D′

MIN</sub>) and the calculated average value (N<sub>D′

MOY</sub>),

if the calculated average value (N<sub>D′

MOY</sub>) is equal to the recorded minimum value (N<sub>D′

MIN</sub>), then the contact detection originates from the user,

if the calculated average value (N<sub>D′

MOY</sub>) is greater than the recorded minimum value (N<sub>D′

MIN</sub>), then the contact detection originates from a spurious contact.

3. The method for determining spurious contacts as claimed in claim 1, characterized in that, during the step c, the matching of the threshold number of charge transfers (N′

_Dth) is carried out in the following manner;

the first value of the threshold number of charge transfers (N<sub>D′

1th</sub>), once the evaluation time (t) has passed, is calculated based on the average of the number of charge transfers (N_DMOY) calculated over the predetermined evaluation time (t) from which a first tolerance has been removed (Δ

N1),

the following values of the threshold number of charge transfers (N<sub>D′

th</sub>) are calculated based on a moving average of the number of charge transfers (N_D′

) from which a second tolerance (Δ

N2) has been removed.

4. The method for determining spurious contacts as claimed in claim 1 claim 3, characterized in that the first tolerance (Δ

N1) and the second tolerance (Δ

N2) are equal.

5. The method for determining spurious contacts as claimed in claim 1, characterized in that the evaluation time (t) is less than the duration of engagement of the locking mode (t₁ , t₂).

6. The method for determining spurious contacts as claimed in claim 1, characterized in that the steps a, b and c are carried out by the detection sensor (4).

7. The method for determining spurious contacts as claimed in claim 1 , characterized in that the steps a, b and c are carried out by the onboard electronic locking/unlocking system (6) of the vehicle (1).

8. An automobile vehicle (1) incorporating a device implementing the method for determining spurious contacts as claimed in claim 1.

9. The method for determining spurious contacts as claimed in claim 2, characterized in that, during the step c, the matching of the threshold number of charge transfers (N′

_Dth) is carried out in the following manner;

the first value of the threshold number of charge transfers (N<sub>D′

1th</sub>), once the evaluation time (t) has passed, is calculated based on the average of the number of charge transfers (N_DMOY) calculated over the predetermined evaluation time (t) from which a first tolerance has been removed (Δ

N1),

the following values of the threshold number of charge transfers (N<sub>D ′

th</sub>) are calculated based on a moving average of the number of charge transfers (N_D′

) from which a second tolerance (Δ

N2) has been removed.

10. The method for determining spurious contacts as claimed in claim 9, characterized in that the first tolerance (Δ

N1) and the second tolerance (Δ

N2) are equal.

11. The method for determining spurious contacts as claimed in claim 2, characterized in that the evaluation time (t) is less than the duration of engagement of the locking mode (t₁, t₂).

12. The method for determining spurious contacts as claimed in claim 2, characterized in that the steps a, b and c are carried out by the detection sensor (4).

13. The method for determining spurious contacts as claimed in claim 2, characterized in that the steps a, b and c are carried out by the onboard electronic locking/unlocking system (6) of the vehicle (1).