Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication
Reexamination Certificate
2001-07-09
2003-07-29
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
C701S072000, C701S083000, C701S084000, C188S11200R, C280S423100, C303S140000, C303S146000
Reexamination Certificate
active
06600974
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and a device for detecting a pendulum motion of a vehicle.
BACKGROUND INFORMATION
In a vehicle, which can be a vehicle combination composed of a towing vehicle and a trailer or semitrailer or a drawbar trailer, snaking movements or pendulum motions can occur due to crosswinds or other influences such as irregularities in the roadway. Since this problem occurs to a greater degree in vehicle combinations, and is by far more dangerous for such vehicles than for single vehicles, in the following, the device and the method of the present invention are discussed in view of vehicle combinations. However, this is not intended to represent any restriction. The use of the device and the method of the present invention is equally conceivable for individual vehicles.
If a vehicle combination experiences snaking movements or pendulum motions, then the trailer oscillates about its vertical axis, and, by way of the trailer coupling, also stimulates the towing vehicle to oscillate. If the vehicular speed is below a so-called critical speed, then the oscillations are damped. If the vehicular speed is equal to the critical speed, then the oscillations are undamped; if the vehicular speed is above the critical speed, then the oscillations increase in amplitude. The value of the critical speed is a function, inter alia, of geometric data such as wheel base and drawbar length, of the mass and the yaw moment of inertia of the vehicle and of the trailer, as well as of the slip-angle rigidity of the axles. In the case of vehicle combinations in the passenger-car sector, this value typically varies in the range from 90 to 130 kilometers per hour. The frequency of the oscillatory motion, i.e. of the pendulum motion, is approximately 0.5 to 1.5 Hz.
In the case of the vehicle dynamics controls presently on the market, such as are described, for example, in the publication “
FDR—Die Fahrdynamikregelung von Bosch
” (VDC—The Vehicle Dynamics Control of Bosch) which appeared in the
Automobiltechnischen Zeitschrift
(ATZ) (Automobile Technology Periodical) 96, 1994, issue 11 on pages 674 through 689, it may be that the above-described snaking movements lead to controller interventions;
however, since these vehicle dynamics controls are primarily designed for single vehicles (in this case, passenger cars), and the regulation of the vehicle yaw rate is in the fore, the controller interventions are carried out in a manner which is not yet optimal. Against this background, there is a need to equip existing vehicle dynamics controls with a detection means by which pendulum motions can be recognized. Consequently, in response to an existing pendulum motion, the controller interventions best suited for this situation can be carried out.
Therefore, the present invention relates to a method and a device for detecting a pendulum motion of a vehicle. Such methods and devices are already known in a great variety of modifications from the related art.
Thus, for example, a method is known for improving the lateral stability of motor vehicles, in which vehicle-decelerating measures are taken when the amplitude of a vehicle lateral-motion-dynamics quantity oscillating within a predefined frequency band exceeds a predefined limiting value. To that end, it is ascertained whether a plurality of successive amplitudes of the vehicle lateral-motion-dynamics quantity exceed the limiting value allocated to it within a predefined time. This procedure requires far too much effort and is therefore costly, and thus is not well-suited for use in the vehicle sector. A consideration of the vehicular speed is not provided.
Also known is a system with which, inter alia, snaking of a vehicle is detected and which warns the driver when snaking is recognized. For this purpose, the vehicle contains a lateral-acceleration sensor. To detect the snaking, the frequency and the amplitude of the signal ascertained with the aid of the lateral-acceleration sensor are observed. In this case, the frequency is derived from the time interval of successive zero crossings. Because of the great expenditure, this procedure is also not well-suited for use in the vehicle sector. Snaking exists when the frequency thus determined lies within a predetermined frequency band, and when the amplitude is greater than a threshold value. In connection with this system, it is further suggested that, in addition to the lateral acceleration, the speed and/or the steering angle of the vehicle be considered. However, a concrete consideration of the speed or of the steering angle is not pointed out.
SUMMARY OF THE INVENTION
Starting from this known related art, the object of the present invention is to provide a method and a device, respectively, for detecting a pendulum motion of a vehicle which have a simpler design compared to the related art, and furthermore, get along with a lower expenditure of computing power.
At this point, reference is made to the SAE paper 973284
“Vehicle Dynamics Control for Commercial Vehicles
”, in which a vehicle dynamics control designed for a vehicle combination is described in a general manner. Both this publication and the above-indicated “
FDR—Die Fahrdynamikregelung von Bosch
” are hereby incorporated by reference
The device of the present invention is a device for detecting a pendulum motion of a vehicle. This device includes at least one first ascertainment means with which a lateral-motion-dynamics quantity representing the lateral-motion dynamics of the vehicle is determined. The device also includes second ascertainment means with which a speed quantity describing the speed of the vehicle is determined. In a third ascertainment means, as a function of the at least one lateral-motion-dynamics quantity and the speed quantity, it is determined whether a pendulum motion of the vehicle exists. For that purpose, it is at least advantageously checked whether the at least one lateral-motion-dynamics quantity is greater than an associated threshold value, and the speed quantity is greater than an associated threshold value. A pendulum motion of the vehicle exists when the at least one lateral-motion-dynamics quantity is greater than the associated threshold value, and when the speed quantity is greater than the associated threshold value.
It is abundantly clear that a lateral-motion-dynamics quantity must be evaluated to recognize a pendulum motion, since the lateral-motion-dynamics quantity contains information about this motion. The speed quantity is evaluated for the following reason: As already mentioned at the outset, the progression of the pendulum motion is dependent to a great extent on the speed of the vehicle relative to the critical speed. If the vehicular speed lies below the critical speed, then it is a question of a damped pendulum motion which is less critical than an undamped pendulum motion or even a pendulum motion that is increasing in amplitude, since such a pendulum motion will end by itself after a while. That is to say, as long as the vehicular speed is below the critical speed, monitoring with regard to a pendulum motion is not absolutely necessary, and therefore also does not have to be carried out. Consequently, computing power for monitoring or detection, which in this case is not urgently necessary, is not tied up unnecessarily. At the same time, in order to have a certain safety reserve, the threshold value necessary for this is advantageously set to be lower by a safety distance than the actual critical speed. This represents a great advantage compared to the known related art, in which the monitoring or detection is carried out constantly, i.e., regardless of the vehicular speed.
As already mentioned at the outset, the device of the present invention for detecting a pendulum motion of a vehicle is used within the framework of a device for regulating a quantity describing the dynamics of the vehicle operation, particularly a quantity describing the yaw rate of the vehicle. As can be gathered from the above-indicated publication “
FDR—Die Fahrdynamikr
Gibson Eric M
Kenyon & Kenyon
Robert & Bosch GmbH
Zanelli Michael J.
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