Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1999-09-02
2002-03-26
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C280S728100
Reexamination Certificate
active
06363306
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a safety device for vehicles. In particular, the present invention is intended to detect a state in a vehicle which corresponds to the vehicle rotating about its longitudinal axis (so called “roll-over”). The present invention also relates to a method utilizing such safety device.
BACKGROUND OF THE INVENTION
In connection with motor vehicles, there are certain kinds of accidents where the vehicle tilts so heavily that it rolls about its longitudinal axis. This, of course, causes great risks of injuries to those travelling in the vehicle. Recently, safety systems have thus been designed which comprise a sensor arranged to detect the presence of such a “roll-over” state. Such a sensor can be connected to a control unit, which in turn is connected to some kind of protective device, which can be activated to protect those travelling in the vehicle when the vehicle rolls over. An example of such a safety device is a safety bar intended for open-top vehicles, which during roll-over is unfolded from a folded-away position to a position where it extends across the passenger compartment, and thus protects the passengers.
For reasons of safety, it is desirable to detect this roll-over state in a reliable manner. In particular, it must be possible to detect such a state at an early stage during an accident, and in a manner such that it can be separated from other similar states of the vehicle. In this way, it is possible to prevent unnecessary activation of safety devices in the vehicle.
In connection with safety systems of the above-mentioned type, it is known to utilize a sensor which detects the angle of inclination of the vehicle relative to the horizontal plane. If the inclination of the vehicle exceeds a certain predetermined threshold value, a signal can be generated which in turn activates a safety device.
A previously known system for detecting a roll-over state in a vehicle, and for activation of a safety bar if such a state is present, is shown in document European Patent No. 430,813. This system comprises a sensor of the gyrometer-kind, and accelerometers for detecting side and vertical acceleration of the vehicle. Using the signals from the respective sensors, the system can thus determine whether the vehicle is about to roll over. In particular, the angular or rotational speed of the vehicle is detected using the gyrometer, i.e. relative to the horizontal plane. Additionally, the system is arranged to determine whether the ratio between the side and the vertical acceleration exceeds a certain threshold value. If this is the case, the signal is integrated with respect to the angular speed which is detected using the gyrometer. If the signal which is obtained from this integration, and which indicates a value of the current angle of the vehicle, exceeds a certain threshold value, a safety device in the form of a safety bar will be activated.
However, although this previously known system does, in principle, provide an efficient function, it has a drawback in that it does not always sufficiently reliably detect whether the vehicle is about to roll over. Furthermore, there is also a risk that this state is not detected rapidly enough during the course of an accident.
The object of the present invention is to provide an improved device for quick and reliable detection of a rollover-state in a vehicle with, in particular, the above-mentioned drawbacks being eliminated.
SUMMARY OF THE INVENTION
In accordance with the present invention, this and other objects have now been realized by the invention of a safety device for detecting the rotation of a vehicle having a longitudinal axis, a transverse axis and a steering wheel comprising angular position means for determining the angular position and angular speed of rotation of the vehicle about at least one of the longitudinal axis and the transverse axis, a control unit for comparing the angular position and angular speed of rotation with predetermined threshold values for the angular position and the angular speed of rotation, at least one of the threshold values being variable and based upon at least one predetermined operational condition of the vehicle, and at least one protective device actuatable by the control unit based upon the comparison.
In accordance with one embodiment of the safety device of the present invention, the control unit includes means for comparing the angular speed of rotation about the longitudinal axis with a first predetermined threshold value, and if the angular speed of rotation about the longitudinal axis exceeds the first predetermined threshold value, comparing the angular position about the longitudinal axis with a second predetermined threshold value, the second predetermined threshold value being variable and based upon the magnitude of the angular speed of rotation, and if the angular position about the longitudinal axis exceeds the second predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of present invention, the safety device includes a first transducer for determining the side acceleration of the vehicle, the control unit including means for comparing the side acceleration to a third predetermined threshold value and if the side acceleration exceeds the predetermined threshold value, comparing the angular position about the longitudinal axis with a fourth predetermined value, the fourth predetermined threshold value being variable and based upon the side acceleration, and if the angular position about the longitudinal axis exceeds the fourth predetermined threshold value, calculating the time during which the side acceleration has exceeded the third predetermined threshold value, comparing the time during which the side acceleration has exceeded the third predetermined threshold value with a fifth predetermined threshold value, the fifth predetermined threshold value being variable and based upon the side acceleration and the angular position, and if the time during which the side acceleration has exceeded the third predetermined threshold value exceeds the fifth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the safety device includes a second transducer for determining the angular position of the steering wheel, and a third transducer for determining the velocity of the vehicle, the control unit including means for comparing the angular position about the longitudinal axis with a sixth predetermined threshold value, and if the angular position about the longitudinal axis exceeds the sixth predetermined threshold value, comparing the velocity of the vehicle with a seventh predetermined threshold value, the seventh predetermined threshold value being variable and based upon the angular position about the longitudinal axis, and if the velocity of the vehicle exceeds the seventh predetermined threshold value, comparing the angular position of the steering wheel with an eighth predetermined threshold value, the eighth predetermined threshold value being variable and based upon the angular position and the velocity of the vehicle, and if the angular position of the steering wheel exceeds the eighth predetermined threshold value, actuating the at least one protective device. Preferably, the control unit includes means for determining the angular velocity of the steering wheel with respect to the direction of turning of the steering wheel, and for comparing the angular position about the longitudinal axis with a ninth predetermined threshold value, and if the angular position about the longitudinal axis exceeds the ninth predetermined threshold value, comparing the speed of the vehicle with a tenth predetermined threshold value, the tenth predetermined threshold value being variable and based upon the angular position about the longitudinal axis, and if the speed of the vehicle exceeds the tenth predetermined threshold value, comparing the angula
Palmertz Camilla
Saméus Jörgen
Gibson Eric M.
Kilpatrick & Stockton LLP
Volvo Personvagnar AB
Zanelli Michael J.
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