Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
2001-04-17
2002-04-16
Camby, Richard M. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S072000, C701S074000
Reexamination Certificate
active
06374171
ABSTRACT:
The present invention concerns, in part, an apparatus as defined in the preambles of claims 1and 10, and a method as defined in the preamble of claim 15.
Each of commonly assigned patent references DE 40 39 629 C2 (which has a corresponding PCT reference WO 92/10377) and DE 42 28 414 A1 relate to devices and methods in the field of regulating vehicle dynamics or movements. According to an abstract of DE 40 39 629 C2, it concerns a system for generating signals for adjusting or controlling a vehicle body. To reduce certain movements of the vehicle, speed sensor signals and suspension deflection sensor signals are involved in determining the vehicle speed and the longitudinal and transverse vehicle accelerations. Vehicle movements, which may include “proper” swinging, pitching-or-rolling movements and “proper” vertical displacements of the front and rear of the vehicle, are involved in compensating or controlling the vehicle suspension systems. Additionally, according to an abstract of DE 42 28 414 A1, a signal processing system detects a first set of signals that represent the movement of the vehicle relative to a fixed reference system, and uses these signals to provide a corresponding set of corrected signals for a travel path of the vehicle. In particular, the sensor signals may represent the transverse velocity and the longitudinal, transverse and vertical accelerations of the vehicle. As discussed in the abstract, the system may be used to control or regulate an active vehicle suspension system, and may correct for certain vehicle movements relative to an inclined path that may be associated with the gravitational acceleration components of the measured signals.
Vehicle brake-by-wire systems, such as, for example, electromechanical brake systems or electro-hydraulic brake systems, may be equipped with wheel braking force control, wheel braking torque control or other anti-lock brake control systems, and may also be provided with a deceleration control system. In a deceleration control system of a brake-by-wire system, there may be no fixed setpoint value for a wheel deceleration that may be associated or correlated with a particular level of brake-pedal travel or brake-pedal force that corresponds with the experience or experiential frame of reference of a driver. Accordingly, a deceleration control system may present certain problems in determining or obtaining an expected or setpoint deceleration value for a particular point on a “driver” or a “brake pedal operation” characteristic curve. It is believed that this is because in such a deceleration control system or “deceleration pedal” braking system, an unpressed brake pedal may correspond to a wheel deceleration of zero (0) and an actuated or depressed brake pedal may correspond to a wheel acceleration that is less than zero (0). In particular, one problem that may occur, for example, is when a driver is driving down a hill. In such a case, the driver may achieve wheel acceleration even while depressing the brake pedal. Any such wheel acceleration, of course, should be less than the wheel acceleration that might result if the driver did not actuate or depress the brake pedal. That is, when driving down a hill, the vehicle may accelerate more if the brake pedal is not actuated or depressed. If the driver increases the force on the brake pedal, this should reduce wheel acceleration to zero (0) and eventually make it negative so that there is wheel deceleration, rather than wheel acceleration.
This braking behavior may be simulated by determining an instantaneous unbraked wheel acceleration and adding it as an offset to a characteristic curve of the “brake pedal operation” for a driver. If the unbraked wheel acceleration offset is not determined during actual braking conditions, however, then the characteristic curve of the “brake pedal operation” may depart (in a possibly dangerous manner or way) from the experience or experiential frame of reference of the driver. For example, when driving off of a car transporter ramp, for example, or down some other incline, a driver may brake on the ramp or other inclined surface to adjust the deceleration to zero (0). The offset that is determined or obtained, however, may be for an accelerating vehicle. Accordingly, if the same operation of the brake pedal is used to adjust the deceleration to zero (0) after the vehicle moves to a relatively level surface, then the brakes may open or otherwise become ineffective. Since the driver may not decelerate by depressing the brake pedal while on a level road, this result may be inconsistent with the experiential frame of reference of the driver.
As further regards the implementation of a wheel deceleration control systems and/or an anti-lock brake system control system, such an implementation may be problematic since the controlled deceleration of the wheels may make it impractical for the wheel speed sensors to measure the wheel speeds when the wheel speeds are dropping relatively sharply because of relatively high wheel decelerations. In this regard,
FIG. 1
shows a graph of wheel deceleration control at low friction values (&mgr;), in which V
fahrzeug
corresponds to a vehicle speed or velocity V
vehicle
, V
Rad, soll
corresponds to a desired wheel speed V
wheel-desired
and V
Rad, ist
corresponds to an actual wheel speed V
wheel-actual
. In particular,
FIG. 1
shows deceleration control at low friction values (&mgr;), in which the actual wheel speed conforms to the desired wheel speed, and in which the wheel slip becomes increasingly greater until the wheel locks when a vehicle speed is not zero (0).
In certain anti-lock brake control systems, wheel locking may be detected by comparing the vehicle speed with the wheel speeds. As a practical matter, however, wheel slip and other factors may complicate the process of detecting or determining the actual vehicle speed or velocity. Accordingly, in certain anti-lock brake control systems, vehicle speed may be determined approximately based on each of the wheel speeds. Thus, for example, the output of a wheel speed sensor on each wheel may be provided to a processor for an anti-lock brake control system, in which the wheel speeds are compared to determine an estimated vehicle speed. The estimated vehicle speed may, of course, be differentiated to determine the vehicle acceleration or deceleration. If any wheel (or set of wheels) exceeds or drops below some predetermined velocity rate and/or acceleration rate, a correcting control signal may be applied to the braking system to compensate for any locking or slipping of a wheel. Accordingly, if a more accurate vehicle velocity—which depends on the wheel slip(s), could be determined, it is believed that a more accurate or efficient anti-lock braking control system may be provided.
The method and apparatus of some exemplary embodiments of the present invention are characterized in that a plurality of deflection displacements are determined, and then at least one wheel slip of a vehicle and at least one of a pitch angle, a road angle, and a roll angle of the vehicle are determined based on the plurality of deflection displacements. Also, at least one wheel slip of a vehicle and at least one of the pitch angle, the road angle, and the roll angle of the vehicle may be provided or otherwise made available to at least one vehicle control system.
In view of the above needs and problems, one embodiment of the present invention is directed to an apparatus for determining at least one wheel slip of a vehicle and at least one of a pitch angle, a road angle and a roll angle of the vehicle for use in at least one vehicle control system, characterized in that the apparatus includes: at least three sensing devices that are adapted for sensing a first parameter that corresponds to a longitudinal acceleration, a second parameter that corresponds to a transverse acceleration, and a third parameter that corresponds to a vertical acceleration; and a processor that determines the at least one wheel slip of the vehicle and the at least one of the pitch angle, the r
Schanzenbach Matthias
Weiberle Reinhard
Camby Richard M.
Kenyon & Kenyon
Robert & Bosch GmbH
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