Fluid-pressure and analogous brake systems – Multiple systems – Fluid pressure and electric
Reexamination Certificate
1998-02-09
2001-05-22
Schwartz, Chris (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple systems
Fluid pressure and electric
C303S015000, C303S140000, C701S078000
Reexamination Certificate
active
06234583
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of adjusting a predetermined, variable braking pressure in the wheel brakes of a brake system, wherein input quantities which determine the braking pressure in the individual wheel brakes are ascertained in a control and data-processing system, and actuation times, or control variables of hydraulic valves, actuators, or like elements, by which the braking pressure is controlled, are established.
BACKGROUND OF THE INVENTION
In vehicle control systems of most various types which are based on brake management or brake actuation, there is a demand for a method of continuously adjusting a predetermined, variable braking pressure or braking pressure variation in the individual wheel brakes. This control method should be adept, easy to realize and adaptable to different conditions and different control modes. Vehicle control systems of the type at issue include, for example, traction slip and driving stability control systems, systems for automatic control of the distance between moving automotive vehicles (AICC—Autonomous Intelligent Cruise Control), purely electrical vehicle brake systems (brake-by-wire), etc. The object of the present invention is to provide a pressure control method of this type.
SUMMARY OF THE INVENTION
It has been found that this object can be achieved by the method described in the attached claim
1
. Some embodiments are described in the subclaims. The adjustment of the braking pressure in a method for driving stability control is a particularly advantageous embodiment of the present invention.
In a method of the type described in the preamble of claim
1
, the special features of the present invention include that the input quantity which determines the braking pressure and is calculated, for example, in a yawing torque controller, and the time derivatives of the input quantity are weighted and added in a pressure controller for each individual wheel. The sum which thereby develops is sent to a non-linear transmission element, and a pressure fluid volume flow is determined from this sum by way of the transmission element in dependence on the characteristics of the hydraulic valves used or the actuators used. In a valve actuation logic unit or valve switching times logic, the actuation times or control times of the hydraulic valves controlling the pressure increase and the pressure decrease or actuators are established as a function of the ascertained pressure fluid volume flow and the valve or actuator characteristic.
In particular quantities representative of the pressure, the pressure fluid volume or the wheel slip are appropriate as input quantities of the pressure controller.
According to the present invention, a two-position or three-position switch, if necessary, switches with a change-over hysteresis, is provided as a non-linear transmission element depending on the case of application and the requirements.
The control method of the present invention provides a simple, robust and stable control structure. The control method can be achieved by circuit hardware, or by software, or by way of programmed circuit technology.
The control method is equally appropriate for use in hydraulic switch valves, proportional valves, hydraulic actuators, and like elements, as components for braking pressure control.
Further features, advantages and possible applications of the present invention can be seen in the following description of an embodiment by way of the attached function charts.
REFERENCES:
patent: 5711025 (1998-01-01), Eckert et al.
patent: 5732379 (1998-03-01), Eckert et al.
patent: 5735584 (1998-04-01), Eckert et al.
patent: 5862503 (1999-01-01), Eckert et al.
patent: 43 12 404 (1994-10-01), None
patent: 0 381 957 (1990-08-01), None
patent: 2 695 367 (1994-03-01), None
patent: 92/05986 (1992-04-01), None
ITT Manufacturing Enterprises Inc.
Rader & Fishman & Grauer, PLLC
Schwartz Chris
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