Method and device for recognizing cornering and for stabilizing a vehicle in case of over-steered cornering

Abstract

Methods and devices for detecting cornering and in particular over-steered cornering, as well as a method and a device for stabilizing a vehicle in case of an over-steered cornering maneuver are described. The detection can be carried out with reference to wheel slip values and/or transverse acceleration values. The stabilization is carried out upon detection of the over-steered cornering maneuver by means of suitable interventions in the brake system.

1 - 59 . (canceled)  
   
   
       60 . Method for detecting an over-steered cornering maneuver of a vehicle, comprising the steps of: 
 determining of the wheel speeds of several wheels and    determining vehicle condition values,    detecting over-steered cornering with reference to one or more of the determined vehicle condition values,    wherein cornering is detected, if the following condition is met:        Sh−Sv>a , wherein    Sh is a value describing the vehicle condition, which has been determined with reference to at least one vehicle condition value,    Sv being a value describing the vehicle condition, which has been determined with reference to at least one vehicle condition value,    selecting reduction of the brake pressures or corresponding nominal values on the wheels located towards the inside of the curve,    increasing the driving moment on the rear axle,    changing the response thresholds of braking assistance functions, wherein the vehicle condition values are transverse acceleration for a front and a rear axle of the vehicle.    
   
   
       61 . Method according to  claim 60 , wherein the vehicle condition values are transverse acceleration for a front and a rear axle of the vehicle.  
   
   
       62 . Method according to  claim 61 , further including detecting a brake event.  
   
   
       63 . Method according to  claim 61 , wherein an over-steered cornering maneuver is detected, if the following condition is met:  
     
       

       Aqha−Aqva>b,  

       Aqha being the transverse acceleration on the rear axle,  
       Aqva being the transverse acceleration on the front axle, and  
       b being a safety value.  
     
   
   
       64 . Method according to  claim 63 , wherein the values that are used as slip values or transverse acceleration values are averaged with respect to time or integrated, whereby the averaging or integration is carried out over a minimum period of time.  
   
   
       65 . Method according to  claim 64 , wherein the minimum period of time is between 250 and 500 ms.  
   
   
       66 . Method according to  claim 61 , wherein the transverse acceleration Aq of an axle is determined with reference to the formula  
         Aq =(( Vr+Vl )( Vr−Vl ))/(2 d )  Vr being the wheel speed of the right wheel on this axle,    Vl being the wheel speed of the left wheel on this axle, and    d being the track on this axle.    
   
   
       67 . Method according to  claim 61 , wherein the curve direction is determined by comparing the slip values or wheel speed values of at least one left wheel with the values of at least one right wheel, considering preferably the wheels of the non-driven axle.  
   
   
       68 . Device for detecting an over-steered cornering, comprising: 
 a first detecting device for detecting the wheel speeds of several wheels, and    a second detecting device for detecting the vehicle condition, and    a third detecting device for detecting over-steered cornering with reference to several of the determined vehicle condition values, wherein the third detection device detects over-steered cornering, if the following condition is met:        Sh−Sv>a      Sh being a value describing the vehicle condition which has been determined with reference to at least one vehicle condition value,    Sv being a value describing the vehicle condition which has been determined with reference to at least one vehicle condition value, and a being a safety value,    a device for selectively reducing the brake pressures or the corresponding nominal values on the wheels located towards the inner side of the curve,    a device for increasing the driving moment of the rear axle,    a device for changing a response threshold of a braking assistance function, wherein the vehicle condition values are transverse acceleration for a front and a rear axle of the vehicle.    
   
   
       69 . Device according to  claim 68 , further including an interrupting device which interrupts the detection of over-steered cornering, if a brake intervenes.  
   
   
       70 . Device according to  claim 68 , wherein said third detecting device detects over-steered cornering, if the following condition is met:  
     
       

       Aqha−Aqva>b  

       Aqha being the transverse acceleration on the rear axle,  
       Aqva being the transverse acceleration on the front axle, and  
       b being a safety value.  
     
   
   
       71 . Device according to  claim 70 , further including a device which produces an average value or an integral value used as wheel speed values or slip values, the averaging or integration being carried out over a minimum period of time.  
   
   
       72 . Device according to  claim 71 , wherein the minimum period of time is between 250 and 500 ms.  
   
   
       73 . Device according to  claim 68 , wherein said second detecting device determines the transverse acceleration of Aq of the center of the axle with reference to the formula  
         Aq =(( Vr−Vl )( Vr−Vl ))/(2 d )  Vr being the wheel speed of the right wheel on this axle,    Vl being the wheel speed of the left wheel on this axle, and    d being the track on this axle.    
   
   
       74 . Device according to  claim 68 , wherein the direction of the curve is determined by comparing the slip values or wheel speed values of at least one left wheel with those of at least one right wheel.  
   
   
       75 . Device according to  claim 68 , further including a selection device for selecting the output of the second detecting device, if relatively low transverse accelerations or wheel slip values are determined, and failing this selecting the output of the third detecting device.  
   
   
       76 . Device according to  claim 68 , further including a device for producing a test value according to one or several transverse acceleration values or one or several wheel slip values, the test value being compared with a threshold value.