DE102012101282A1 - Method for recognizing threatening flight phase of motor car by e.g. radar sensor, involves detecting vertical inclination angle of road in travel direction and/or distance of road based on true airspeed of vehicle to recognize phase - Google Patents

Abstract

The method involves detecting a vertical inclination angle (B) of a road in a travel direction and/or distance (D) of the road by using an environment detection sensor. The detected vertical angle and the distance of the road are evaluated based on true airspeed (V) of a vehicle. A threatening flight phase of the vehicle is recognized from the evaluated vertical angle and the evaluated distance of the road when a true airspeed-dependant variable maximum inclination angle and true airspeed-dependant variable maximum road distance are exceeded. An independent claim is also included for a control device for a motor car.

Description

The invention relates to a method for detecting an imminent flight phase of the vehicle by means of at least one environment detection sensor according to the preamble of claim 1.

When a phase of a vehicle is understood when one or more wheels or even the entire vehicle have lost contact with the road. This is also taken from English as so-called "Airborne" situation called and occurs in particular when driving over hills, ramps or the like, wherein for a flight phase, the change of the road in the vertical direction, ie in the vertical axis of the vehicle and thus perpendicular to the decisive from the longitudinal axis and transverse axis driving plane is crucial.

Such a phase of flight is due to the uneven center of gravity distribution in the vehicle by a Abnicken, ie a rotation about the transverse axis of the vehicle, characterized as usually located there, heavy engine pulls the front of the vehicle due to the influence of gravity in the direction of the road. Such a phase of flight differs from a so-called rollover situation in that the rollovers associated with the term "rollover" are primarily rotational movements of the vehicle about the longitudinal axis, ie the roll rate and its summation to an absolute roll angle and the achievement of a static roll or dynamic tilt angle goes.

While rollover situations are now well recognized by their own algorithms partly based on additionally arranged in the vehicle yaw rate sensors and avoided by intervention of the ESP system and in case of unavoidable protection devices are activated, suitable measures for such flight phases have been hardly discussed.

However, accident statistics show that such a flight phase often leads to extreme driver misconduct and serious accidents involving serious injury to passengers as well as other involved road users.

From the EP2289753 A1 is a method and a control device for detecting or plausibility of such a flight phase of a vehicle refer. In particular, suitable sensors and algorithms for detecting such a flight phase on the basis of the acceleration signal in the direction of the vertical axis of the vehicle are taught there. The disadvantage here is that during the flight phase itself no contact of all wheels is more to the road and thus intervention to avoid danger is hardly possible.

In addition, for example, from the DE 37 38 221 C2 Even an environment detection sensor for detecting road bumps known, but neither suitable parameters are measured here nor an imminent flight phase derived from it.

The object of the present invention is therefore to be able to detect the threat, ie the imminence of such a flight phase, in order to be able to initiate measures for avoiding or reducing the effects. This object is solved by the features of the independent claims. Advantageous developments of the invention will become apparent from the dependent claims, wherein combinations and developments of individual features are conceivable with each other.

An essential idea of the invention is that the sensor detects the vertical inclination angle of the road in the direction of travel and / or the distance to the road and evaluates it taking into account the intrinsic speed of the vehicle and from this an impending flight phase is detected. The vertical inclination angle of the road in the direction of travel is the angle in the direction of travel X, which is between an imaginary horizon line and the road. Alternatively, however, the vertical inclination angle of the road can also be viewed from the perspective of the sensor in the vehicle and the inclination angle of the vehicle can either be ignored or preferably likewise sensed and taken into account mathematically. The measurable distance to the road from the sensor is initially detectable over the duration of emitted beams or triangulation from a stereo camera image as the distance between the sensor and the road. In addition, from this size, the purely vertical offset (in the Z direction) can be derived on the basis of the known per se angle of the beam path of the sensor.

As environment detection sensors can be used, for example, the known radar or Lidarsensoren, mono or stereo camera systems, preferably also with an active irradiation, for example in the IR spectrum, and in particular combinations of these in the sense of a sensor fusion.

While in principle both sizes mentioned already allow for an estimate of the imminent flight phase, of course, in a preferred embodiment, both variables are recorded and taken into account.

It is irrelevant in technically reasonable limits and adaptable by adjusting the limits where exactly in the area of the road the vertical inclination angle of the road in the direction of travel or to which position in the Road course, the distance is measured, so for example, directly on the front edge of the vehicle or a few feet ahead, because preferably the road ahead is detected at several points, preferably over an entire section while driving and so creates a nearly continuous height profile of the road. Preferably, the profile can also detect a certain width of the road in the transverse direction Y, in particular approximately corresponding to the wheelbase, and thus also recognize a possible only one-sided imminent tipping of a vehicle side.

Unless it is an edge crossing, so with an inclination angle of almost 90 °, the risk of impending flight phase also depends on the vehicle's own speed, that is, with correspondingly low airspeed, the vehicle would not lose contact with the road, the higher However, the airspeed is, the higher is the risk of a flight phase at a certain vertical angle of inclination or a distance to the road, which of course is greater than the normal distance when driving straight ahead.

For the assessment of whether a flight phase threatens, therefore, preferably an intrinsically speed-dependent variable maximum inclination angle is predetermined and an impending flight phase is detected as soon as this maximum inclination angle is exceeded. Alternatively or additionally, an own speed-dependent variable maximum road distance is given and an imminent flight phase is detected as soon as this maximum road distance is exceeded.

In addition, of course, the properties of the vehicle to be considered, ie in particular its center distance, mass, axle load distribution or center of gravity and moment of inertia about the transverse axis.

These quantities need not be determined separately, but are included in the determination of the parameters, in particular the thresholds and can be determined by tests on the vehicle or in the simulation.

Preferably, the course of the vertical inclination angle of the road in the direction of travel and / or the distance to the road is detected and evaluated, in particular from the signal of the sensor (s) for at least one predetermined area of the road a vertical road height profile is determined and evaluated, for example with stored patterns or characteristics are compared taking into account the airspeed and based on which the risk of impending flight phase decided.

Such an invention will be realized in the form of a control device for a motor vehicle, which is equipped with at least one environment detection sensor and an evaluation algorithm for performing the method, wherein the sensor detects the vertical inclination angle of the road in the direction of travel or the distance to the road, preferably both sizes and the controller is evaluated in consideration of the vehicle's own speed. The control unit can now detect an imminent flight phase from this and upon detection of an imminent flight phase of the vehicle, ie even before the loss of contact with the road, a warning to the driver, other control devices and / or control interventions to avoid the flight phase and / or the protection of the occupants carry out. The range of suitable measures ranges from an emergency braking to reduce the vehicle's own speed, possibly even to a level below the risk of a flight phase to measures to prepare the vehicle for an impact, ie a rough landing after the flight phase. Appropriate measures are described in a number of parallel applications by the Applicant.

The invention will now be explained in more detail by means of exemplary embodiments with the aid of the figures. In the following, functionally identical and / or identical elements may be designated by the same reference numerals. Show it

1 : Vehicle at dome crossing and significant angles and distances

1 shows a vehicle on a hill, wherein the vehicle moves at an airspeed V, which in these embodiments proves to be too large for the shown vertical inclination angle B of the road or the distance D to the road, ie a flight phase is unavoidable.

The road ahead of the vehicle is detected by the sketchy indicated rays of the environmental detection sensor and converted into a road height profile from which the respective vertical tilt angle B and distance D result for the respective positions X in the road.

In this case, H denotes a virtual reference line to a natural horizon, against which the pitch angle A of the vehicle itself around its pitch axis, that is to say the transverse axis of the vehicle in the Y direction, is evaluated. However, for the claimed method, the vertical inclination angle of the road may be used both as angle B with respect to the horizon H and as vertical Inclination angle with respect to the vehicle, which corresponds to the angle A + B.

In addition, based on the airspeed V and the road height profile, the control unit can estimate an expected time of incidence on the road and a presumed impact angle C1 or C2 at that time, the angle of incidence being C2 either opposite the virtual horizon line H or C1 can be assessed on the actual course of the road, in order to additionally derive the strength of the danger due to the flight phase.

Although the beam sensor can no longer detect the vertical inclination angle B in the area immediately in front of the vehicle at the time shown, due to the limited viewing angle E of the beam sensor, it has nevertheless detected this by previous recordings at earlier points in time. At an even steeper angle of inclination B, a never detectable remaining blind spot area is created, which, however, is so critical anyway that a blanket estimate is possible and a flight phase is unavoidable. If you want to avoid this, it simply requires additional sensors with a stronger angle of inclination to the road to quasi to a vertical measurement, for example, from the vehicle leading edge perpendicular to the road. Since in such a case, however, there are hardly any possibilities for averting danger and reducing the present embodiment is limited to already provided in the vehicle for other tasks environment detection sensor and their albeit limited field of view, but usually sufficient for those situations in which Procedures also preventive measures are possible.

Although all the steeper hills or ramps can no longer be distinguished from one another by the sensors, they can at least be allocated in a uniform class of situations and stored for these uniform measures.

Of course, in addition to the environment detection sensor system described here, the control unit can also evaluate the signals of other sensors, such as acceleration signals and yaw rate signals of the initial sensor system of the ESP system, for example, and use it to check the plausibility of the ambient detection sensor signals.

As a vehicle in addition to cars in particular motorcycles and other road vehicles in question.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2289753 A1 [0006]
• DE 3738221 C2 [0007]

Claims (7)

A method for detecting an imminent flight phase of the vehicle by means of at least one environment detection sensor, characterized in that the sensor detects the vertical inclination angle (B or A + B) of the road in the direction of travel and / or the distance (D) to the road and taking into account the airspeed (v) the vehicle evaluated and from an imminent flight phase is detected. A method according to claim 1, characterized in that an own speed-dependent variable maximum inclination angle (Bmax (v)) is predetermined and an impending flight phase is detected as soon as this maximum inclination angle is exceeded. A method according to claim 1, characterized in that an own speed-dependent variable maximum road distance (Dmax (v)) is predetermined and an imminent flight phase is detected as soon as this maximum road distance is exceeded. Method according to one of the preceding claims, characterized in that the course of the inclination angle of the road in the direction of travel (B (x)) and / or the distance to the road (D (x)) is timed and evaluated. Method according to one of the preceding claims, characterized in that from the signal of the sensor for at least one predetermined area of the road, a vertical road height profile (Z (x)) is determined and this is evaluated. Method according to one of the preceding claims, characterized in that the road detected at a predetermined width transverse to the direction of travel and the vertical inclination angle (B / A + B) of the road in the direction of travel and / or the distance (D) to the road over at least several points is detected on this width. Control unit for a motor vehicle having an environment detection sensor and an evaluation algorithm for carrying out the method according to any one of the preceding claims, wherein the sensor detects the vertical inclination angle of the road in the direction of travel and / or the distance to the road and the control unit evaluated taking into account the intrinsic speed of the vehicle and therefrom recognizes an imminent flight phase and performs a warning to the driver and / or control interventions to prevent the flight phase and / or the protection of the occupants upon detection of an impending flight phase of the vehicle.

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