Method for rollover detection for automotive vehicles with safety-related devices

#1. Field of the Invention

#The present invention relates to a method for rollover detection for automotive vehicles with safety-related devices, in which the angular velocity of rolling or rotary motions around the longitudinal axis (roll-axis) of the vehicle is measured by means of a gyrosensor.

#2. Description of the Related Technology

#An embodiment according to the method of the invention is explained in detail in the following and illustrated by the figures.

#They show:

#FIG. 1 a block diagram of a safety system for performing the method according to the invention with an angular rate sensor;

#FIG. 1 shows, as an embodiment of the method according to the invention, a safety system for automotive vehicles with an ignition stage 9 for triggering a safety-related device, such as a roll bar, a seat-belt tensioner or (side) airbags. This safety system comprises an angular rate sensor or gyrosensor 1, which generates a signal proportional to the angular velocity ωx (angular rate) around the longitudinal axis (X-axis) of the vehicle, which is fed to a function block 4 for calculating the angle of rotation integral ∫ωxdt, a function block 6 for generating a trigger threshold value S(ω) according to the formula αtip−k|ω| and a function block 7 for the plausibility test. Thereby the vehicle-specific constant k is matched to the vehicle concerned, whereby this is determined, for example, from concrete crash signatures of a specific vehicle type and/or has been determined through experiments with this vehicle type. This constant k may also be variably set as a function of the vehicle state and/or from the crash sequence, that is as a function of the measured α and/or ω values. For example, k might be reduced if large α or ω values suddenly occur and the trigger threshold value S(ω) is thus lowered in order to ensure early triggering of the safety-related device if there is a fast rollover. Furthermore, prior α and/or ω values, that is the prior history of the vehicle state and/or a crash sequence, may be included. In this way, low α or ω values which have been present for a long time could lower the constant k with a consequent lowering of the trigger threshold value S(ω) in order to ensure reliable triggering even when the vehicle is turning over slowly. If the course of the prior ω values and/or signal components (for example, az or ay) of additional sensors enables a conclusion to be made about the wheels rebounding, this can be interpreted as the start of a rollover and lead to adaptation of the constant k, in that it is reduced.

#Furthermore, an initial position sensor 2 is provided which generates a signal α0 proportional to the inclination of the transverse axis (Y-axis) of the vehicle in relation to the horizontal plane which is passed on to a function block 5 for generating an integration constant αstart. Finally, additional sensors 3 are provided for detecting additional dynamic vehicle states, such as acceleration sensors in the direction of the vertical axis (Z-axis) and, if applicable, the transverse axis (Y-axis) whose measured values az and ay and the signal α0 of the initial position sensor 2 are fed to the function block 7, whose function is described below.

#The output signals of the function blocks 4 and 5 are added or summed to a value αcurr,calc proportional to the current inclination angle in the transverse direction of the vehicle with a summing element 13 according to the formula