Method for detecting a rollover of a motor vehicle

Abstract

A method for detecting a rollover on the basis of a signal of an acceleration sensor in the direction of the vertical axis of the vehicle is described, wherein the time period in which acceleration lies within a specified range is assessed. For this purpose, a counter and a clock generator are provided, wherein the counter is incremented each clock pulse if acceleration lies within a specified range, and the counter is decremented maximally to the value of zero if acceleration lies outside of a specified range. An emergency call may be triggered if a specified counter reading is reached. Additionally, a maximum speed may be specified in the travel direction above which the counter or the triggering is not active.

Claims

1. A method for detecting a rollover on the basis of a signal of an acceleration sensor in the direction of the vertical axis of the vehicle on the basis of the time period in which acceleration lies within a specified range, comprising: Providing a counter and a clock generator, wherein the counter is incremented each clock pulse if acceleration lies within a specified range, and the counter is decremented maximally to the value of zero if acceleration lies outside of a specified range; and wherein the only sensors used for detecting the rollover has occurred are the counter, the clock generator and the acceleration sensor.

2. The method according to claim 1, wherein an emergency call is triggered if a specified counter reading is reached.

3. The method according to claim 2, wherein a speed sensor for the vehicle is used to measure vehicle speed and the counter is incremented only if the speed of the vehicle in the travel direction is lower than a specified maximum speed.

4. The method according to claim 3, wherein an emergency call is triggered only if the speed of the vehicle in the travel direction is lower than a specified maximum speed.

5. The method according to claim 3, wherein a value below 40 km/h is provided as the specified maximum speed.

6. The method according to claim 3, wherein a value below 15 km/h is provided as the specified maximum speed.

7. The method according claim 2, wherein as a counter reading for triggering an emergency call, a value is recorded that will be reached at the earliest if acceleration continuously lies within the specified range for at least 500 milliseconds.

8. The method according to claim 1, wherein detecting a rollover is independent of using an angular rate sensor.

9. A control device for a motor vehicle comprising: an algorithm for detecting a rollover on the basis of a signal of an acceleration sensor in the direction of the vertical axis of the vehicle on the basis of the time period in which acceleration lies within a specified range, wherein a counter and a clock generator are provided, the counter is incremented each clock pulse if acceleration lies within a specified range, and the counter is decremented maximally to the value of zero if acceleration lies outside of a specified range; and wherein the only sensors used for detecting the rollover has occurred are the counter, the clock generator and the acceleration sensor.

10. The control device of claim 9, wherein an angular rate sensor is not provided.

11. A method for detecting a rollover of a vehicle, said method comprising: receiving a signal of an acceleration sensor; receiving a clock pulse; incrementing a counter each clock pulse in response to the signal from the acceleration sensor indicating that acceleration in the direction of a vertical axis of the vehicle is within a specified range; decrementing the counter each clock pulse in response to the signal from the acceleration sensor indicating that acceleration in the direction of the vertical axis of the vehicle is outside of the specified range; determining a rollover has occurred when a specified counter reading is reached; and wherein the only sensors used for detecting the rollover has occurred are the counter, the clock generator and the acceleration sensor.

12. The method according to claim 11, further comprising triggering an emergency call in response to the specified counter reading being reached.

13. The method according to claim 12, wherein a speed sensor for the vehicle is used to measure vehicle speed and incrementing the counter only occurs if the speed of the vehicle in the travel direction is lower than a specified maximum speed.

14. The method according to claim 13, wherein triggering the emergency call occurs only if the speed of the vehicle in the travel direction is lower than a specified maximum speed.

15. The method according to claim 13, wherein the specified maximum speed is a value below 40 km/h.

16. The method according to claim 13, wherein the specified maximum speed is a value below 40 km/h.

17. The method according to claim 13, wherein the specified maximum speed is a value below 15 km/h is provided as the specified maximum speed.

18. The method according to claim 13, further comprising setting a counter reading for triggering an emergency call at a value that will be reached at the earliest if acceleration continuously lies within the specified range for at least 500 milliseconds.

19. The method according to claim 11, wherein detecting a rollover is independent of using an angular rate sensor.

Description

DETAILED DESCRIPTION

(1) Methods for detecting a rollover on the basis of a signal of an acceleration sensor (and also for triggering an emergency call) are disclosed that are capable of operating without using any angular rate sensors in case of doubt (see DE 10 2008 040 295 A1, for example). The acceleration in the direction of the vertical axis of the vehicle and, in particular, the time period in which acceleration lies within a specified range are assessed. Specifically, the influence of gravitational force on the acceleration sensor in the vertical axis changes significantly when the vehicle lies on its roof or is in an extremely oblique position.

(2) A counter and a clock generator are provided, the counter is incremented each clock pulse if acceleration lies within a specified range, and the counter is decremented by the value of one each clock pulse if acceleration lies outside of a specified range, wherein the maximum decrement is down to the value of zero, which also corresponds to the initial value.

(3) At it, the specified range is adaptable depending on the respective vehicle and application, but is intended to correspond to a situation in which the vehicle substantially lies on its roof, i.e., in the case of an acceleration sensor in the vertical axis directed toward the ground it is intended to be, e.g., a range of up to at least +1 g if the amount of the loss in gravitational force starts from 0.7 g (normalized base value of 1 g for an upright vehicle; rollover starting from 0.3 g), wherein g is gravitational force.

(4) An emergency call is preferably triggered if a specified counter reading is reached. In contrast to purely temporal assessments, an advantage of such a method consists in the fact that occasional incorrect measured values (each of them being a single error) result in a counter reading value that is incorrect only by the value of one if the counter reading is considerably different from 1 and preferably is at least 10, but have no decisive influence on the overall assessment.

(5) Moreover, in a further development, the counter is incremented only if the speed of the vehicle in the travel direction is lower than a specified maximum speed. Thus, this method detects only rollovers that occur out of normal vehicle operation. However, this is entirely sufficient for an emergency call function.

(6) An alternative provision may be that the counter is incremented but an emergency call is triggered only if the speed of the vehicle in the travel direction is lower than a specified maximum speed.

(7) As a maximum speed, a value below 40 km/h, preferably below or equal to 15 km/h, is provided, wherein these values are only first experimental values and are adaptable according to the respective vehicle application.

(8) As a counter reading for triggering an emergency call, a value is recorded that will be reached at the earliest if acceleration continuously lies within the specified range for, e.g., 500 milliseconds to 4 seconds. If intermediate values deviate, there will be no complete reset but an incremental reduction of the counter so that triggering will occur after a correspondingly longer time period. This final counter value is also adaptable.

(9) In one embodiment, such a counter is purely realized as a software in a control device for a motor vehicle, i.e., a corresponding algorithm is stored in the memory and loaded during operation.

(10) The present disclosure has been described herein in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims.