Method and apparatus for controlling a vehicle occupant protection device

• US 7,499,781 B2
• Filed: 03/05/2001
• Issued: 03/03/2009
• Est. Priority Date: 09/04/1998
• Status: Expired due to Fees

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Hermann, Stefan
• Primary Examiner(s): Jeanglaud; Gertrude Arthur
• Application Number:
  US09/799,751
• Publication Number:
  US 20010025215A1
• Time in Patent Office: 2,920 Days
• Field of Search: 701/45, 701/46, 180/232, 180/268, 180/271, 280/728.1, 280/734, 280/735
• US Class Current: 701/45
• CPC Class Codes: B60R 2021/0102 the monitored value being used for calculating occupant displacement
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/0133 by integrating the amplitude of the input signal
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

A method for controlling a vehicle occupant protection device includes the steps of providing a mass of a vehicle as an operand and a dependence between a deformation of the vehicle body and work to be performed for the deformation. The vehicle acceleration is recorded with an acceleration sensor. The vehicle occupant protection device is controlled as a function of the mass of the vehicle, the work, and the acceleration. To control the device, the mass and the dependence are stored in a memory. The actual deformation of the vehicle body that occurs during an accident is determined as a function of acceleration recorded, the work, and the mass of the vehicle. The vehicle occupant protection device is controlled as a function of the actual deformation of the vehicle body or of a variable derived from it. An apparatus for controlling the device includes an acceleration sensor having a memory and an arithmetic unit.

Claims

1. A method for controlling a vehicle occupant protection system, which comprises:

providing a value of a mass of a vehicle as an operand from a memory;

providing, from the memory, information indicating a dependence between a deformation of a vehicle body and work to be performed for the deformation;

sensing a vehicle acceleration with an acceleration sensor; and

controlling a vehicle occupant protection device as a function of the mass of the vehicle, the work, and the acceleration.

2. The method according to claim 1, which further comprises determining an actual deformation of the vehicle body as a function of the acceleration, the work, and the mass of the vehicle.

3. The method according to claim 2, which further comprises deriving the actual deformation of the vehicle body from the equation:

$A<br><br>\left(s\right)={\int <br><br>}_0^s<br><br>m·<br><br>a<br><br>\left(s\right)<br><br>d<br><br>s,$

where m is the mass of the vehicle, a is the acceleration, s the deformation of the vehicle body, and A is the work necessary for the deformation.

4. The method according to claim 2, which further comprises controlling the vehicle occupant protection device as a function of one of the actual deformation of the vehicle body and a variable derived from the actual deformation of the vehicle body.

5. The method according to claim 1, which further comprises determining an impact velocity as a function of the acceleration, the work, and the mass of the vehicle.

6. The method according to claim 5, which further comprises controlling the vehicle occupant protection device as a function of one of the determined impact velocity and a variable derived from the impact velocity.

7. The method according to claim 5, which further comprises:

determining an actual deformation of the vehicle body as a function of the acceleration, the work, and the mass of the vehicle; and

deriving the impact velocity from the actual deformation of the vehicle body.

8. The method according to claim 7, which further comprises deriving the impact velocity from the actual deformation of the vehicle body using the equation:

$s<br><br>\left(t\right)=v_0·<br><br>t+{\int <br><br>}_0^t<br><br>{\int <br><br>}_0^t<br><br>a<br><br>\left(t\right)<br><br>d<br><br>t^2$

where s is the actual deformation of the vehicle body, v₀ is the impact velocity, a is the acceleration, and t is time.

9. The method according to claim 5, which further comprises:

calculating the impact velocity at a plurality of times; and

using, after a transient response, one of an averaged impact velocity and a late impact velocity as a basis for further calculations.

10. The method according to claim 1, which further comprises determining an expected power drain for the vehicle.

11. The method according to claim 10, which further comprises performing the determining step by determining the expected power drain according to the equation:

$\mathrm{Ee}=\frac{m}{2}·<br><br>{\left(v_0+{\int <br><br>}_0^t<br><br>a<br><br>\left(t\right)<br><br>d<br><br>t\right)}^2,$

where, m is the mass of the vehicle, v₀ is the impact velocity, a is the acceleration, and t is time.

12. The method according to claim 4, which further comprises supplying an enable for the vehicle occupant protection device if the actual deformation of the vehicle body exceeds a limiting value within a predefined time from a start of an impact.

13. The method according to claim 4, which further comprises:

determining an expected power drain for the vehicle; and

supplying an enable for the vehicle occupant protection device if the actual deformation of the vehicle body exceeds a limiting value and simultaneously the expected power drain exceeds a further limiting value.

14. The method according to claim 1, which further comprises estimating an acceleration (a(t+Δ

t)) for a future time.

15. The method according to claim 14, which further comprises:

determining an estimated forward displacement (x(t+Δ

t)) of the vehicle occupant for the future time using the estimated acceleration (α

(t+Δ

t)); and

supplying an enable for the vehicle occupant protection device if the future forward displacement (x(t+Δ

t)) of the vehicle occupant exceeds a threshold value.

16. The method according to claim 15, which further comprises:

providing the dependence between the deformation of the vehicle body and the work to be performed for the deformation as a function of an impact angle;

estimating a future acceleration for each angle-dependent item of work;

estimating the acceleration (a₆₀ (t+Δ

t)) for the future time based on each impact-angle-dependent work curve made available; and

comparing the acceleration recorded at the future time with the estimated accelerations (a_α

(t+Δ

t)).

17. The method according to claim 16, which further comprises using an impact-angle-dependent work curve forming the basis for the estimated acceleration (a_α

(t+Δ

t)) having a smallest deviation from the recorded acceleration for further calculations.

18. The method according to claim 16, wherein an impact-angle-dependent work curve forming the basis for the estimated acceleration (a_α

(t+Δ

t)) having the smallest deviation from the recorded acceleration defines the impact angle, and which further comprises controlling the vehicle occupant protection device as a function of the impact angle determined.

19. The method according to claim 1, which further comprises determining the work to be performed for a deformation of the vehicle body in a crash trial.

20. The method according to claim 19, which further comprises performing the determining step by determining the work to be performed for a deformation of the vehicle body in a crash trial with a high impact velocity and in a crash trial with a low impact velocity.

21. An apparatus for controlling a vehicle occupant protection device of a vehicle having a given mass and a body, comprising:

an acceleration sensing system for recording a vehicle acceleration;

a memory for storing a value of the mass of the vehicle and information indicating a dependence between a deformation of the vehicle body and a work to be performed for the deformation; and

an arithmetic unit for controlling the vehicle occupant protection device as a function of the acceleration, the work, and the mass of the vehicle, said arithmetic unit connected to said memory and to said acceleration sensing system.