Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Earth science
Reexamination Certificate
1999-09-29
2003-05-06
Bui, Bryan (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Earth science
C701S074000, C303S163000
Reexamination Certificate
active
06560539
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and a device for determining a quantity describing the speed of a vehicle.
BACKGROUND INFORMATION
Methods and devices for determining a quantity describing the speed of a vehicle are known from the Prior Art in a multitude of modifications.
In German Published Patent Application No. 38 33 212 (U.S. Pat. No. 5,272,634), the formation of a reference quantity for the vehicle speed outside of a brake force regulator is described for a vehicle having two-wheel drive and furnished with an anti-lock control system. Essentially, in this context, based on the speeds of the two driven wheels, an average wheel speed is ascertained. If the temporal derivation of this averaged wheel speed is greater than zero, then the reference quantity is determined by the speed of the slower of the two driven wheels. If the temporal derivation of this averaged wheel speed is smaller than zero, then the reference quantity is determined by the speed of the faster of the two driven wheels. In this context, the increase of the reference quantity for the vehicle speed is limited by a maximum value.
German Published Patent Application No. 40 09 195 (U.S. Pat. No. 5,364,174) describes the formation of a reference speed required for the slip control of an anti-lock control system installed in a four-wheel-drive vehicle. Essentially, in this context, the reference speed, in response to an increase in speed, is determined by the speed of the slowest wheel and, in response to a decrease in speed, is determined by the speed of the third-fastest wheel. In the transitional area between increase and decrease, the obtained value of the slowest wheel speed is kept constant. In the event that the speed of the third-fastest wheel deviates too greatly from an auxiliary reference speed, the reference speed is maintained parallel to this auxiliary reference speed. The auxiliary reference speed is formed by being raised by the speed of the third-fastest wheel and by being lowered by the speed of the fastest wheel. It too is kept constant in a transitional range. In the event of instability caused by a locking tendency, the rise of the reference speed is determined by the rise of the auxiliary reference speed. If the wheels make a complete revolution, the reference speed is kept constant and the increase of the auxiliary reference speed is limited to a physically possible vehicle acceleration. If the rear wheels of the four-wheel-drive vehicle are decoupled from the drive in response to braking, a slightly modified formation of the reference speed is used. Apart from the control, the reference speed is increased if the speeds of all wheels are greater than it. If two or three wheels are faster than the reference speed, then it is kept constant. If none or only one of the wheels is faster than the reference speed, then the reference speed is adjusted downwards.
In German Published Patent Application No. 43 14 830 A1 a method is described for determining the reference speed of a vehicle. For this purpose, the wheel circumference speeds, the vehicle longitudinal acceleration, and the vehicle transverse acceleration are ascertained. Various driving situations are distinguished for the vehicle as a function of the vehicle longitudinal acceleration and the vehicle transverse acceleration. As a function of the respective driving situation, a group of wheel speeds is selected, the reference speed being formed from the selected wheel speeds. In the driving situation “braking general,” the reference speed is calculated as the amount the highest wheel circumference speed of all four wheels. In the driving situation “accelerations, steady driving, engine thrust operation,” the reference speed is generated as the arithmetic average of the wheel circumference speeds of the wheels that are not driven. In the driving situations “braking on a left curve” and “braking on a right curve,” the wheels having the greatest load are determinative for the reference speed.
German Published Patent Application No. 39 17 976 describes a method for determining the vehicle speed in a motor vehicle having rear-engine drive. For this purpose, the angular speeds of the front wheels and at least the average angular speed of the two rear wheels of the vehicle are measured. In addition, the acceleration of the vehicle is determined at least roughly in the vehicle's longitudinal direction. In response to a positive acceleration of the vehicle, the vehicle speed is calculated using the angular speed of at least one of the front wheels. In response to a strong deceleration of the vehicle, the vehicle speed is calculated using the greatest angular speed of the individual wheels of the vehicle.
The aforementioned German Published Patent Application No. 38 33 212 describes an anti-lock control system that contains a slip control. In the context of this slip control system, a reference quantity must be created. The magnitude of the reference quantity is determined, in each case, only by one of the wheel speeds of the driven wheels. For this purpose, the average value of the two wheel speed signals of the driven wheels is ascertained. If the rise of this average value is greater than zero, then the magnitude of the reference quantity is determined by the wheel speed signal of the slower wheel. If the rise of this average value is less than zero, then the magnitude of the reference quantity is determined by the wheel speed signal of the faster wheel.
Systems for controlling brake slip and drive slip are generally known, for example, from the book published by Robert Bosch GmbH Stuttgart, “Brake Systems For Automobiles”, VDI Printing House, Duesseldorf, first edition, 1994.
Systems for controlling a quantity describing the driving dynamics of a vehicle are, for example, described in the publication “FDR—The Driving Dynamics Control of Bosch,” in
Automotive Technical Journal
(ATZ) 96, 1994, volume 11, on pages 674 through 689.
SUMMARY OF THE INVENTION
An objective of the present invention is a more precise determination of a quantity describing the speed of a vehicle.
This is achieved with a method for determining a quantity describing the speed of a vehicle using the motion characteristics of the vehicle and the wheel performance. The advantage of the method and the device of the present invention over conventional methods and devices is that the quantity describing the speed of the vehicle according to the present invention can be ascertained for a vehicle according to the present invention having any drive system, i.e., for a front-wheel-drive, back-wheel-drive, or four-wheel-drive vehicle for any given operating state of the vehicle. In this context, the determination of the quantity describing the vehicle speed does not depend on whether, during the determination, the control system implemented in the vehicle is active in the sense of a brake slip control or a drive slip control, or in the sense, for example, of a control system superordinated to the brake or drive slip control for controlling a quantity describing the driving dynamics of the vehicle.
Heretofore, for the varied vehicle drive concepts and for every type of slip control system that has been used in a vehicle, it was necessary to have a separate method and a separate device for determining the quantity describing the speed of the vehicle. With the method of the present invention and with the device of the present invention, there is now a method and a device which can be used for every type of slip control system.
The universal applicability of the method of the present invention and thus also of the device of the present invention rests, first, on the fact that the quantity describing the speed of the vehicle is formed on the basis of an advantageously selected baseline, which takes into account a component describing the speed of the vehicle and a component describing the acceleration of the vehicle. Second, it rests on the fact that at the time of the formation of the quantity describing the speed of the vehicle, the current operat
Kost Friedrich
Mueller Elmar
Wuerth Gebhard
Bui Bryan
Kenyon & Kenyon
Robert & Bosch GmbH
Vo Hien
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