Fluid-pressure and analogous brake systems – Speed-controlled – Torque sensing
Reexamination Certificate
1999-06-11
2001-04-17
Butler, Douglas C. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
Torque sensing
C188S00111E, C188S158000, C188S162000, C188S18100R, C188S00111E, C303S003000, C303S155000, C303S020000
Reexamination Certificate
active
06217131
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and a device for controlling a vehicle braking system in open loop.
BACKGROUND INFORMATION
One demand on the closed-loop control system of a vehicle braking system is the correct adjustment of the clearance (air gap) between the brake pad and the brake disc. In the classic hydraulic brake, gaskets provide for the withdrawal of the piston in the pressureless state, and thus for the lifting of the brake pads. In connection with the electromechanical brake, in which the brake application is effected, e.g., by an electric motor, the clearance must be actively adjusted by sending the current through the actuator in the negative direction. Motor-vehicle wheel brakes operated by electric motors are known, for example, from PCT Publication No. WO 94/24453 or German Published Patent Application No. 19 526 645. The size of the clearance cannot be detected by a braking-torque or braking-force sensor. Therefore, the clearance is adjusted on the basis of a path signal (travel path of the brake pads), e.g., based on a motor rotational angle, which is in relation to the travel path of the brake pads as defined by a fixed characteristic curve. In this context, the exact knowledge of the zero path or of the zero angle, at which the brake pads just contact the brake disc, is important. Furthermore, if the intention is to use only one controller for the braking torque or the braking force, the correlation between the path variable and the controlled variable is crucial.
SUMMARY OF THE INVENTION
An object of the present invention is to specify measures by which this zero variable and/or this correlation can be ascertained.
The design approach, described in the following, sets forth a reliable, precise procedure for determining the zero path or the zero angle at which the brake pads have in fact just contacted or just released the brake disc or brake drum.
This zero variable is known at any time by the estimation, so that a reliable clearance adjustment is also possible after brakings at rest and/or additional test brakings for identification of the zero variable. The need for a scanning to the zero point is eliminated. so that no time is lost in adjusting the clearance. The described procedure estimates the zero point at any instant on the basis of the braking-torque signal or the brake-application force signal and the path or angle signal, it being possible to adjust the clearance quickly and correctly even after a quick-stop braking.
Because of the pronounced offset drift of the torque or force sensor, as well as due to appearances of wear, and temperature influences, it cannot be assumed that the contact angle of the brake pads with the disc will not change during a braking. Furthermore, a faulty and/or drift-affected angle measurement can invalidate the result. These influences are taken into account by the constant estimation of the zero point. A constant adjustment of the torque or force sensor takes place, errors in detecting the path or angle are compensated, and characteristic curves which represent the characteristic properties of the brake are adapted.
In this manner, a quick and accurate clearance adjustment is made possible, even using a closed-loop braking-torque control, in all operating states, i.e., at standstill, as well.
If an open-loop control of the wheel brakes is carried out within the framework of a closed-loop braking-moment or braking-force control using a single controller, the described procedure ensures that the correlation between the measured path signal and the torque- or force signal, used in so doing, is constantly adapted. In this manner, the open-loop control is improved above all with a view to the comfort during braking (no sudden change during the switch-over from the measured value to a calculated) and during the adjustment of the clearance.
REFERENCES:
patent: 4327414 (1982-04-01), Klein
patent: 4658939 (1987-04-01), Kircher et al.
patent: 4685745 (1987-08-01), Reihecke
patent: 4784244 (1988-11-01), Carre et al.
patent: 4995483 (1991-02-01), Moseley et al.
patent: 5234262 (1993-08-01), Walenty et al.
patent: 5366280 (1994-11-01), Littlejohn
patent: 5539641 (1996-07-01), Littlejohn
patent: 5915504 (1999-06-01), Döricht
patent: 5957246 (1999-09-01), Suzuki
patent: 5962997 (1999-10-01), Maisch
patent: 6000507 (1999-12-01), Böhm et al.
patent: 6003640 (1999-12-01), Ralea
patent: 6008604 (1999-12-01), Maisch
patent: 6012556 (2000-01-01), Bloschet et al.
patent: 6040665 (2000-03-01), Shirai et al.
patent: WO 94/24453 (1994-10-01), None
patent: 195 26 645 (1997-01-01), None
Butler Douglas C.
Kenyon & Kenyon
Robert & Bosch GmbH
LandOfFree
Method and device for controlling a vehicle braking system... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for controlling a vehicle braking system..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for controlling a vehicle braking system... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2550226