DE10202908B4 - Method and arrangement for determining a detection range of a pre-crash sensor system - Google Patents

Abstract

_(Spun t) a Anspannzeit a safety device of the vehicle and a driving state variable (V _own: wherein a detection range (d _max, d _min) is determined characterized in that a maximum detection distance (d _max) is determined in dependence on at least precrash Sensierungsverfahren, , a _eigen , W _g , eigen) of the vehicle, a collision probability of driving state variables and measurement data is determined, and in the event that a collision probability exceeds a threshold, a triggering threshold of a driving algorithm of a pyrotechnic ignitable restraint is set before impact and / or at least a reversible restraining means, preferably a reversible electro-motor belt tensioner and / or electromagnetic or electromotive adjusting means for adjusting a foot, knee or head position, are operated.

Description

The The invention relates to a method and an arrangement for determination a detection area of a pre-crash sensor system.

to Investigation of potential accidents From motor vehicles, pre-crash sensing methods are known. These Procedures use non-tactile sensors that are in the vehicle environment for example, a relative speed, a time to one expected impact, impact angle and expected impact location of an object on a collision course. In addition, impact probabilities can determined and discriminated by means of video sensors objects and object classes be assigned.

The Pre-crash sensing is a passive safety feature of the Vehicle and divided into three stages. Build these steps in functional terms, since they each have a higher level of complexity and sensor capability require. Furthermore, these stages also follow in terms of time until the crash event.

The First stage is generally PRESST ("PREcrash SETting of algorithm thresholds ") and relates to an adjustment of the triggering thresholds of the control algorithms conventional pyrotechnic ignitable Retention agent. The control of the pyrotechnic ignitable retention means takes place only here after the crash, because the algorithm in addition to the precrash information also considered the conventional acceleration sensors. The second stage is generally PREFIRE ("PREcrash Flring of reversible Restraints ") called and concerns an ignition reversible retention agent due to the pre-crash sensor information already before the crash starts. The third stage is called PREACT ("PRecrash Engagement of ACTive safety"). With her, in the detection of an accident probability, the above exceeds a threshold to be defined, systems of active Safety, especially brakes, engine control, steering, activated.

The Detection and determination of for the precrash sensing required payload is done via appropriate Sensors in a dependent of the respective sensor detection area. The activity the respective safety device or the vehicle system active safety is always within a response time or tense time.

at usual Precrash sensing methods are usually all detected by the sensor system Data about objects on the road to calculate an impact probability used. In this case leads the amount of data collected at a considerable computational effort and possibly unnecessary Pre-crash measures. Furthermore, a detection range can be determined by a predetermined minimum Detection distance and a predetermined maximum detection distance which limits the amount of data. Such Determining the relevant detection range is not unproblematic, because they do not respond to the particular circumstances of each occurring driving situations Takes into account.

Out DE 197 49 838 A1 the use of pre-crash sensors is known whose signal is used regardless of the actual occurrence or absence of an impact and that to an actuation of components of a restraint system such that their settings are optimized, wherein after failure of an impact within a predeterminable period, the so operated Components are moved back to their original setting or position. DE 199 60 644 A1 shows that at least one pre-crash sensor is provided, on the impact of the vehicle as an immediately forthcoming signal indicating the respective reversible restraining components such as electrically operated belt tensioners are brought into a pre-activated state or a start position. Out DE 195 46 715 A1 An airbag sensor system is known in which sensors are integrated in a body door, each having a transmitting and receiving stage, with which a microwave signal is radiated, the antenna lobe has a smaller Halbwärtsbreite and is perpendicular to the door surface. The microwave signals reflected at an approaching collision object are applied to an evaluation unit for generating an enable pulse. When generating the enable pulse in an evaluation unit, the integration time of the measuring process of the Doppler pulses is taken into account. In particular, the integration path of the sensor system can be designed to be adaptive.

The inventive method according to claim 1, in contrast in particular the advantage that a determination of a detection range for one respective driving situation possible is that the capture of all guaranteed for accidents of relevant items and yet a suitable limitation of the detection area and thus allowing the detected sensor data. The determination of the suitable detection range is hereby advantageously with relatively little extra expenditure on equipment or calculation effort possible. This is a precrash sensing method created in which the inventive method for determining of the detection area is used.

The invention is based on the knowledge that precrash measures are only relevant for objects whose probable impact is likely to occur at a time interval which is above the Anspannzeit the safety devices and vehicle systems to be operated. According to the invention, a maximum detection distance is now determined from the tensioning time of a safety device or the tensioning times of a plurality of safety devices and driving state variables of the vehicle. The maximum detection distance may preferably take the form of the sum of the path distance presumably covered within the tensioning time-which can be determined by temporal integration of the dynamic properties, in particular the vehicle speed and the vehicle longitudinal acceleration-and a suitable measuring distance. The measuring distance can be predetermined or determined as a function of sensor properties or driving state variables. Accordingly, a minimum detection distance from the Anspannzeit and driving state variables can further be determined, which defines the detection range together with the maximum detection distance.

According to the invention can detected by the sensor system Object are classified and the determined object class - for example Passenger cars, trucks, pedestrians, motorcyclists or cyclists - at the Setting the safety devices are taken into account. The to be set Safety devices can according to the invention both in the aforementioned PRESST stage the triggering thresholds the control log for conventional pyrotechnic ignitable retention means as well as in the PREFIRE stage described above reversible Retention means be. Such reversible retention agents can both the protection of vehicle occupants, for example as reversible electro-motor belt tensioners, electro-motor or electro-magnetic operated paddings, the knees or feet or even the neck and head in the event of a crash by operation protect appropriate adjustment, as well as serve by passers-by. Furthermore you can in the PREACT stage mentioned in the precrash sensing method according to the invention upon detection of an accident probability that exceeds one threshold to be defined, active safety systems, especially brakes, engine control, steering, be activated.

According to the invention is advantageously used a combined sensor concept that has a long-range Sensor device, preferably with a high-frequency or short-wave Radar sensor device, a medium-range sensor device, preferably as a stereoscopic video sensor device with a suitable opening angle, and a kurzreichreichweitige sensor device, in particular with a System of several radar sensors on low-frequency or short-wave basis includes. These sensor devices are combined to form a sensor system which Thus, an adjustment of a detected as relevant detection range over a huge length range allows. additionally The sensor signals are data about the driving condition of the vehicle used from vehicle sensors or derived therefrom variables. In addition to a straight-line movement of the vehicle can this case for example, the set steering angle or a determined yaw rate the vehicle also a detection area when cornering be determined.

According to the invention, the Determination of the detection range both during a stable driving condition as well as during a spinning process allows being while being a spin operation, for example, data of a vehicle dynamics control or an antilock braking system can be used.

The The invention will be described below with reference to the accompanying drawings on some embodiments explained in more detail. It demonstrate:

1 a plan view of a vehicle with a sensor system according to the invention on a roadway;

2 a side view of the representation of 1 with objects on the roadway;

3 a plan view of a vehicle on a straight and curved track;

4 a block diagram of an inventive arrangement.

According to 1 drives a vehicle 1 on a straight lane 2 with a vehicle _speed v _intrinsic and a longitudinal acceleration a _eigen . On the vehicle, a sensor system with three sensor devices is provided. A short-range first sensor device 4 , which uses several radar sensors on 24 GHz basis, is for a first range 5 over a first distance up 7 provided with a first opening angle of 140 °. A medium range second sensor device 6 has a video system, for example a stereoscopic video system, and will be used for a second measuring range with a second distance of about 40 m and a second opening angle of about 35 °. A long-range third sensor device 8th uses a 77 GHz radar sensor and covers a third measuring range with a third distance of 9 to 150 m and a third opening angle of 8 °. The opening angle is chosen to be small, since this range only at height ren speeds on routes with a small radius of curvature, especially highways, is needed.

According to 2 detects the short-range sensor device 4 a first vehicle 12 as an object on the roadway 2 at a distance d of 6 m and the in 2 not shown medium range sensor device 6 a second driving tool 13 at a distance of 20 m to the vehicle 1 , The two captured objects 12 . 13 can from the second sensor device 6 classified in a conventional manner and assigned to the object class "passenger cars".

According to 4 give the first, second and third sensor devices 4 . 6 . 8th first, second and third sensor signals s ₁ , s ₂ , s ₃ to an evaluation device 10 of the vehicle 1 , Here, the first output signals s ₁ z. B. also be used in addition for a parking aid. The evaluation device determines from the sensor signals s ₁ , s ₂ , s ₃ and driving state signals p over different driving state variables, in particular the airspeed v _eigen , the longitudinal vehicle speed a _eigen , the vehicle yaw rate ωg _own and possibly data on the spin cycle or slip behavior of the vehicle control signals a1 for a safety device 14 or a plurality of safety devices, in particular reversible restraining means, such as reversible electro-motor belt tensioners and electro-motor or electromagnetically operated padding for setting a knee, foot, neck or head position, this z. B. the pedals and the headrest of the vehicle seat can be adjusted. Furthermore, by driving signals a ₂ active vehicle systems 16 , for example, brakes, an engine control and steering, controlled.

The evaluation device 10 in this case calculates a detection range with a maximum detection distance d _max and a minimum detection distance d _min . First, d _{max is} calculated as d Max = 0.5 a own · t 2 instep + v own · t instep + d mess with a = _{intrinsically} self-acceleration of the vehicle, t _spun = Anspannzeit the security device 14 , v _eigen = current vehicle speed and d _mess = measuring distance, which can be set to 5 m, for example, and adapted to the respective driving conditions.

This formula can be used directly for the rectilinear motion of the 1 . 2 which correspond to in 3 as a straight lane in front of the vehicle 1 is shown. Calculate the first two terms of this formula - with a straight movement with no spin behavior - which due to the current driving state variables and a _self v _{intrinsically} in the Anspannzeit distance traveled. The third addend is the measuring distance. d _max can be continuously updated here - with new data a _own and v _own . The Anspannzeit t _spun the safety device 14 is generally given and is for example between 100 ms-500 ms. The above calculation can be performed for several Anspannzeiten or the largest Anspannzeit t _spun.

If there is no straightforward movement, but a ride on curvy track, as in 3 is shown in addition, - if no spin behavior is present - d _{max covered} according to the dotted line on a circular section, so that the relevant for the sensor system rectilinear, corrected maximum detection distance d ' _max calculated as the corresponding edge length of the segment formed according to: d ' Max = 2r sin (i Max / (2R)) where r is the radius of curvature of the vehicle.

As an example, consider the safety device 14 means for pedestrian protection with a response or Anspannzeit of t _spun selected = 500 ms, that must have its full effect at start of the crash.

The vehicle has:
an instantaneous airspeed of v _eigen = 500 km / h = 13.9 m / s,
it goes straight ahead (steering angle α _l = 0 °, yaw rate ω _{g, eigen} = 0 ° / s),
it has no self-acceleration (a _eigen = 0 m / s ² ),
there is no spin process.

• – keine Eigengeschwindigkeit relativ zum Fahrzeug,
• – wird als Fußgänger klassifiziert,
• – befindet sich direkt vor dem Fahrzeug.

When measuring distance d _measured 5 m are applied. According to the above formula for a straight-ahead driving results in a d _max of 11.95 m. If an object now enters the detection area <d _max , the sensing algorithms of the various sensor systems and of the evaluation device detect 10 the object and determine a relative speed, a time to an expected impact, an impact angle and an expected impact location, possibly an impact probability and a classification of the object. d _min is initially set to d _min = d _{max -d meas} and a decision time is set to t _decision = d _meas / ( _own + safety margin). With appropriate vehicle behavior, for example, a brake operation and a steering operation to avoid, the parameters change accordingly, so that, for example, the intrinsic velocity v _own falls, the intrinsic _acceleration increases a _self and the steering angle increases, before the detected object is exceeded. The evaluation device 10 Determines the following data for the object:
The object has

• No airspeed relative to the vehicle,
• - is classified as a pedestrian,
• - is right in front of the vehicle.

An impact probability (value between 0 and 1) is continuously calculated and exceeds the applicable threshold of 0.8 at a time before t _decision , so that a crash that requires the restraint system, with sufficient probability is expected. it is now calculated analogously to the calculation of d _max . Decision strategies determine when a final d _{min is} determined. A more complex determination of t _decision is also possible. A change in the response time or Anspannzeit _spun t based on the detected data, in particular of the object class and the relative velocity, is still possible.

According to the invention, d _{max can} each be kept at the lowest possible value, so that the computing power is minimized and yet the function is fully guaranteed. d _min can also be kept as low as possible in order to obtain as much information about the object as possible and thus to maximize the quality and tolerance of the sensor information.

The different safety devices 14 can have different tasks for different situations and thus different clamping times. In this case, for example, the force build-up in a belt tensioner can be dependent on the impact probability.

Claims (1)

_(Spun t) a Anspannzeit a safety device of the vehicle and a driving state variable (V _own: wherein a detection range (d _max, d _min) is determined characterized in that a maximum detection distance (d _max) is determined in dependence on at least precrash Sensierungsverfahren, , a _eigen , W _g , eigen) of the vehicle, a collision probability of driving state variables and measurement data is determined, and in the event that a collision probability exceeds a threshold, a triggering threshold of a driving algorithm of a pyrotechnic ignitable restraint is set before impact and / or at least a reversible restraining means, preferably a reversible electro-motor belt tensioner and / or electromagnetic or electromotive adjusting means for adjusting a foot, knee or head position, are operated.