WO2003068575A1 - Method and device for monitoring and/or modifying brake pressures - Google Patents
Method and device for monitoring and/or modifying brake pressures Download PDFInfo
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- WO2003068575A1 WO2003068575A1 PCT/EP2003/001435 EP0301435W WO03068575A1 WO 2003068575 A1 WO2003068575 A1 WO 2003068575A1 EP 0301435 W EP0301435 W EP 0301435W WO 03068575 A1 WO03068575 A1 WO 03068575A1
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- deceleration
- delay
- determining
- pressure
- vehacc
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
- B60T8/44—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems
- B60T8/441—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems using hydraulic boosters
- B60T8/442—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems using hydraulic boosters the booster being a fluid return pump, e.g. in combination with a brake pedal force booster
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/88—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means
- B60T8/92—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action
- B60T8/94—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action on a fluid pressure regulator
Definitions
- the invention relates to a method for monitoring and / or modifying brake pressures in wheel brakes of a vehicle and a device according to the preamble of claim 9.
- Vacuum brake boosters require a vacuum supply provided by the motor to support the pedal force to be applied by the driver.
- a condition can be reached even at relatively low pedal forces, where a further increase in the force on the actuation unit is only possible by increasing the pedal force, since the vacuum brake booster has reached the maximum possible support force.
- the state is called the modulation point of the amplifier.
- Braking that takes place above the actuation point of the vacuum brake booster places high demands on the driver with regard to the pedal force to be applied. For this reason, brake systems (OHB-V) are increasingly being used, which the driver uses to build up hydraulic brake pressure support.
- Brake systems of this type generally have a motor-pump unit and a hydraulic unit, which are controlled by electronic control, such as ESP, ABS, ASR and the like. can be controlled according to the desired braking force support.
- the (analogized) isolation valves are closed and the hydraulic pump delivers brake fluid from the actuation unit, preferably a tandem master cylinder (THZ), into the wheel brakes.
- the actuation unit preferably a tandem master cylinder (THZ)
- TTZ tandem master cylinder
- the additional pressure generated via the isolating valves must be comfortably reduced in terms of pedal feel and braking effect in the actuation unit.
- the pressure difference between the actuation unit and the brake actuators is set via the analogized isolating valves, which are controlled by means of a current to be set.
- the object of this invention is to monitor and, if necessary, correct the hydraulic effectiveness of the applied brake pressures. According to the invention, this object is achieved in that a generic method is carried out with the following steps:
- a correction of the manipulated variables of the analog valves can advantageously be determined for a short time by the method according to the invention and thus effects can be reduced to an acceptable level, which can consist in that when the brake is released the pedal e.g. due to errors in the pressure model or the valve characteristics, “stick”, or braking occurs.
- the pedal feeling is improved or the comfort increases.
- the invention furthermore relates to designing a generic device such that the device has a first determination unit for determining the deceleration parameters, a comparison unit for comparing the deceleration specification with the actual deceleration, and a second determination unit for determining correction values for the brake pressures according to the specification of comparison.
- the following steps are expedient for deceleration specification and the actual deceleration: determining the pressure of an actuating unit on the basis of measured values, determining the deceleration specification (Req_VEHACC) from the factor-weighted pressure of the actuation unit, determining the correction values from the difference between the deceleration specification and the actual deceleration.
- the pressure of the actuation unit is weighted with an amplification factor.
- the difference between the delay specification and the actual delay is filtered in filters.
- the filters are preferably of the first or second order.
- the difference is filtered with different filter time constants (F_Fast, F_Slow), preferably with cutoff frequencies of 1 Hz and 15 Hz.
- the deviation of the deceleration specification from the actual deceleration is determined by the size of the difference (DIFF) from the difference (VEHACC-REQ_VEHACC) filtered by different filter time constants (F_Fast, F_Slow) and the actual one Delay formed.
- BESTATIGUNGSKOPIE It is particularly advantageous that the deviation is compared with a threshold value and correction values for the brake pressures are formed in accordance with the comparison result.
- the correction values are determined, in particular according to the current setting of an electromagnetically controllable valve, with reference to a formula or a characteristic curve.
- the device which is part of a brake system, is advantageously developed such that a pressure sensor determines the pressure of the actuation unit, that the first determination unit has a correction stage for determining the deceleration specification (Req_VEHACC) from the pressure of the actuation unit weighted by a factor, and that the second determination unit has a subtractor for determining the correction values from the difference between the delay specification and the actual delay.
- a pressure sensor determines the pressure of the actuation unit
- the first determination unit has a correction stage for determining the deceleration specification (Req_VEHACC) from the pressure of the actuation unit weighted by a factor
- Req_VEHACC deceleration specification
- Fig. 1 shows an embodiment of the invention
- the monitoring is carried out via a similarity analysis of the vehicle deceleration specified by the driver via the brake pedal and the vehicle reaction, preferably the actual vehicle deceleration.
- the situation is considered in which the driver is supported by active hydraulic brake pressure build-up (OHB-V).
- the deceleration specification initiated by the driver is determined from the pressure of the actuation unit measured with a pressure sensor, which is multiplied by a gain factor.
- the gain factor results from the hydraulic brake force boost of the driver's specification.
- the increased pressure of the actuation unit is the requested pressure (Req_Press).
- the actuating unit can be a tandem master cylinder (THZ), for example. This value 10 is multiplied by a factor A in a multiplier 11, so that a delay specification (Req_VEHACC) is considered
- the second signal 13 which is used for the comparison in the comparator 12, is the vehicle deceleration signal (VEHACC). This can be determined based on a model or with a
- FIG. 2.1 shows the signal curve over a short period of time, which represents a situation typical for the formation of the delay signals.
- the requested pressure is labeled Req_Press, the deceleration specification with Req_VEHACC and the vehicle deceleration signal with VEACC.
- Typical situations can occur when the brake is released, for example if the pedal sticks, for example due to errors in the pressure model or the valve characteristics, or automatic braking occurs.
- the difference 14 of VEHACC and Req_VEHACC is formed in the subtractor 12. This variable is fed to two filters 15, 16, for example low-pass filters, with different filter time constants (F_Fast, F_Slow).
- the filters are preferably of the first or second order, the cutoff frequencies are 1 Hz or 15 Hz. In this way, as shown in FIG. 2.2, a relatively slowly changing differential signal 14 SF and a differential signal 14 FF which also reflects the faster changes are produced. If the difference 17 from F_Fast-F_Slow is now formed in a further subtractor 18, the deviation of the vehicle reaction (VEHACC) from the driver specification (Req_ VEHACC) can be detected from the size of the difference 17 (DIFF). The size of the deviation 17 is filtered in a low-pass filter 22. The signal 17 and the filtered signal 17F are shown in FIG. 2.3. The threshold value S is determined by the input signal 17F subtracted, block 19. The output signal 19A is limited to values> 0.
- the output signal 21 will be used to correct the pressure model and thus ultimately the current setting of the analog isolating valve.
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Regulating Braking Force (AREA)
Abstract
Description
Verfahren und Vorrichtung zum Überwachen und/oder Modifizieren von BremsdrückenMethod and device for monitoring and / or modifying brake pressures
Die Erfindung betrifft ein Verfahren zum Überwachen und/oder Modifizieren von Bremsdrücken in Radbremsen eines Fahrzeugs und eine Vorrichtung nach dem Oberbegriff des Anspruchs 9.The invention relates to a method for monitoring and / or modifying brake pressures in wheel brakes of a vehicle and a device according to the preamble of claim 9.
Vakuum-Bremskraftverstärker benötigen eine vom Motor zur Verfügung gestellte Unterdruckversorgung zur Unterstützung der von dem Fahrer aufzubringenden Pedalkraft. Abhängig vom Motor kann schon bei relativ geringen Pedalkräften ein Zustand erreicht werden, wo eine weitere Erhöhung der Kraft auf die Betätigungseinheit nur durch eine Steigerung der Pedalkraft möglich ist, da der Vakuum-Bremskraftverstärker die maximal mögliche Unterstützungskraft erreicht hat. Den Zustand bezeichnet man als Aussteuerpunkt des Verstärkers. Bremsungen die über dem Aussteuerpunkt des Vakuum- Bremskraftverstärkers stattfinden, stellen dabei hohe Anforderungen an den Fahrer hinsichtlich der aufzubringenden Pedalkraft. Aus diesem Grund werden zunehmend Bremssysteme (OHB-V) eingesetzt, die durch einen aktiven hydraulischen Bremsdruckaufbau den Fahrer unterstützen. Derartige Bremssysteme weisen in der Regel ein Motor-Pumpen-Aggregat und ein Hydraulikaggregat auf, die von einer elektronischen Regelung, wie ESP, ABS, ASR und dgl . entsprechend der gewünschten Bremskraftunterstützung gesteuert werden.Vacuum brake boosters require a vacuum supply provided by the motor to support the pedal force to be applied by the driver. Depending on the motor, a condition can be reached even at relatively low pedal forces, where a further increase in the force on the actuation unit is only possible by increasing the pedal force, since the vacuum brake booster has reached the maximum possible support force. The state is called the modulation point of the amplifier. Braking that takes place above the actuation point of the vacuum brake booster places high demands on the driver with regard to the pedal force to be applied. For this reason, brake systems (OHB-V) are increasingly being used, which the driver uses to build up hydraulic brake pressure support. Brake systems of this type generally have a motor-pump unit and a hydraulic unit, which are controlled by electronic control, such as ESP, ABS, ASR and the like. can be controlled according to the desired braking force support.
Bei dem Druckaufbau in den Radbremsen mittels hydraulischer Unterstützung über den Aussteuerpunkt des Vakuum- Bremskraftverstärkers hinaus werden die (analogisierten) Trennventile geschlossen und die Hydraulikpumpe fördert Bremsflüssigkeit aus der Betätigungseinheit, vorzugsweise einem Tandemhauptzylinder (THZ) , in die Radbremsen. In der Druckabbauphase muss der zusätzlich erzeugte Druck über die Trennventile komfortabel bezüglich Pedalgefühl und Bremswirkung in der Betätigungseinheit abgebaut werden. Die Einstellung der Druckdifferenz zwischen der Betätigungseinheit und den Bremsen-Aktuatoren erfolgt über die analogisierten Trennventile, die mittels eines einzustellenden Stromes gesteuert werden.When the pressure builds up in the wheel brakes by means of hydraulic support beyond the actuation point of the vacuum brake booster, the (analogized) isolation valves are closed and the hydraulic pump delivers brake fluid from the actuation unit, preferably a tandem master cylinder (THZ), into the wheel brakes. In the pressure reduction phase, the additional pressure generated via the isolating valves must be comfortably reduced in terms of pedal feel and braking effect in the actuation unit. The pressure difference between the actuation unit and the brake actuators is set via the analogized isolating valves, which are controlled by means of a current to be set.
Oben angesprochene Systeme haben das systembedingte Problem, daß Toleranzen, die durch Alterung, Temperatur, oder Ansteuerungsungenauigkeiten hervorgerufen werden, nicht ausgeregelt werden können, da die Systeme bevorzugt ohne Raddrucksensoren betrieben werden. Diese kostengünstige Variante läßt aber nur eine Steuerung zu, welche eine Überwachung der Funktion erforderlich macht.Systems mentioned above have the system-related problem that tolerances caused by aging, temperature or control inaccuracies cannot be corrected, since the systems are preferably operated without wheel pressure sensors. However, this inexpensive variant only allows a controller that requires monitoring of the function.
Aufgabe dieser Erfindung ist es die hydraulische Wirksamkeit der eingesteuerten Bremsdrücke zu überwachen und ggf. zu korrigieren. Erfindungsgemäß wird diese Aufgabe dadurch gelöst, dass ein gattungsgemässes Verfahren mit den folgenden Schritten durchgeführt wird:The object of this invention is to monitor and, if necessary, correct the hydraulic effectiveness of the applied brake pressures. According to the invention, this object is achieved in that a generic method is carried out with the following steps:
Ermitteln der Verzögerungsvorgabe,Determining the delay specification,
Vergleichen der Verzögerungsvorgabe mit der tatsächlichenCompare the delay specification with the actual one
Verzögerung, undDelay, and
Ermitteln von Korrekturwerten für die Bremsdrücke nachDetermine correction values for the brake pressures after
Massgabe des Vergleichs.Condition of the comparison.
Vorteilhaft können durch das erfindungsgemässe Verfahren für eine kurze Zeit eine Korrektur der Stellgrößen der analogen Ventile ermittelt und somit Effekte auf ein akzeptables Mass reduziert werden, die darin bestehen können, dass beim Lösen der Bremse das Pedal z.B. durch Fehler des Druckmodells oder der Ventilkennlinien „kleben,, bleibt oder sich ein Nachbremsen einstellt. Das Pedalgefühl wird verbessert oder der wird Komfort grösser.A correction of the manipulated variables of the analog valves can advantageously be determined for a short time by the method according to the invention and thus effects can be reduced to an acceptable level, which can consist in that when the brake is released the pedal e.g. due to errors in the pressure model or the valve characteristics, “stick”, or braking occurs. The pedal feeling is improved or the comfort increases.
Gegenstand der Erfindung ist ferner, eine gattungsgemässe Vorrichtung so auszugestalten, dass die Vorrichtung aufweist, eine erste Ermittelungseinheit zum Ermitteln der Verzögerungs orgäbe, eine Vergleichseinheit zum Vergleichen der Verzögerungsvorgabe mit der tatsächlichen Verzögerung, und eine zweite Ermittlungseinheit zum Ermitteln von Korrekturwerten für die Bremsdrücke nach Massgabe des Vergleichs.The invention furthermore relates to designing a generic device such that the device has a first determination unit for determining the deceleration parameters, a comparison unit for comparing the deceleration specification with the actual deceleration, and a second determination unit for determining correction values for the brake pressures according to the specification of comparison.
BESTATIGUNGSKOPIE Zum Ermitteln der Korrekturwerte aus derBESTATIGUNGSKOPIE To determine the correction values from the
Verzögerungsvorgabe und der tatsächlichen Verzögerung sind folgende Schritte zweckmäßig: Ermitteln des Drucks einer Betätigungseinheit anhand gemessener Werte, Ermitteln der Verzögerungsvorgabe (Req_VEHACC) aus dem mit einem Faktor gewichteten Druck der Betätigungseinheit, Ermitteln der Korrekturwerte aus der Differenz der Verzögerungsvorgabe und der tatsächlichen Verzögerung.The following steps are expedient for deceleration specification and the actual deceleration: determining the pressure of an actuating unit on the basis of measured values, determining the deceleration specification (Req_VEHACC) from the factor-weighted pressure of the actuation unit, determining the correction values from the difference between the deceleration specification and the actual deceleration.
Nach einer weiteren Ausbildung der Erfindung wird der Druck der Betätigungseinheit mit einem Verstärkungsfaktor gewichtet .According to a further embodiment of the invention, the pressure of the actuation unit is weighted with an amplification factor.
Des Weiteren ist es vorteilhaft, dass die Differenz der Verzögerungsvorgabe und der tatsächlichen Verzögerung in Filtern gefiltert wird. Die Filter sind bevorzugt lter oder 2ter Ordnung.Furthermore, it is advantageous that the difference between the delay specification and the actual delay is filtered in filters. The filters are preferably of the first or second order.
Zur weiteren Verbesserung des Verfahrens, wird die Differenz mit unterschiedlichen Filterzeitkonstanten (F_Fast, F_Slow) , vorzugsweise mit Grenzfrequenzen von 1Hz und 15Hz, gefiltert.To further improve the method, the difference is filtered with different filter time constants (F_Fast, F_Slow), preferably with cutoff frequencies of 1 Hz and 15 Hz.
Zur weiteren Verbesserung der Überwachung bzw. der Modifikation der Bremsdrücke wird die Abweichung der Verzögerungsvorgabe von der tatsächlichen Verzögerung aus der Grosse der Differenz (DIFF) von der mit unterschiedlichen Filterzeitkonstanten (F_Fast, F_Slow) gefilterten Differenz (VEHACC-REQ_VEHACC) der Verzögerungsvorgabe und der tatsächlichen Verzögerung gebildet .To further improve the monitoring or modification of the brake pressures, the deviation of the deceleration specification from the actual deceleration is determined by the size of the difference (DIFF) from the difference (VEHACC-REQ_VEHACC) filtered by different filter time constants (F_Fast, F_Slow) and the actual one Delay formed.
BESTATIGUNGSKOPIE Es ist besonders vorteilhaft, dass die Abweichung mit einem Schwellenwert verglichen wird und nach Massgabe des Vergleichsergebnisses Korrekturwerte für die Bremsdrücke gebildet werden.BESTATIGUNGSKOPIE It is particularly advantageous that the deviation is compared with a threshold value and correction values for the brake pressures are formed in accordance with the comparison result.
Zur Ansteuerung der Trennventile ist es besonders zweckmässig, dass die Korrekturwerte insbesondere nach Massgabe der Stromeinstellung eines elektromagnetisch ansteuerbaren Ventils bezugnehmend auf eine Formel oder eine Kennlinie ermittelt werden.To control the isolating valves, it is particularly expedient that the correction values are determined, in particular according to the current setting of an electromagnetically controllable valve, with reference to a formula or a characteristic curve.
Des Weiteren ist die Vorrichtung, die Bestandteil einer Bremsanlage ist, vorteilhaft so weitergebildet, dass ein Drucksensor den Druck der Betätigungseinheit ermittelt, dass die erste Ermittlungseinheit aufweist eine Korrekturstufe zum Ermitteln der Verzögerungsvorgabe (Req_VEHACC) aus dem mit einem Faktor gewichteten Druck der Betätigungseinheit, und dass die zweite Ermittlungseinheit einen Subtrahierer aufweist, zum Ermitteln der Korrekturwerte aus der Differenz der Verzögerungsvorgabe und der tatsächlichen Verzögerung.Furthermore, the device, which is part of a brake system, is advantageously developed such that a pressure sensor determines the pressure of the actuation unit, that the first determination unit has a correction stage for determining the deceleration specification (Req_VEHACC) from the pressure of the actuation unit weighted by a factor, and that the second determination unit has a subtractor for determining the correction values from the difference between the delay specification and the actual delay.
Ein Ausführungsbeispiel ist in der Zeichnung angegeben und wird im Folgenden näher beschrieben. Es zeigenAn embodiment is shown in the drawing and is described in more detail below. Show it
Fig. 1 eine erfindungsgemässe Ausführungsform zumFig. 1 shows an embodiment of the invention
Überwachen und/oder Modifizieren von BremsdrückenMonitor and / or modify brake pressures
Fig. 2 Darstellungen von Zeitverläufen zu Erläuterung der erfindungsgemässen Ermittlung von Korrekturwerten2 representations of time profiles to explain the determination of correction values according to the invention
Fig.l zeigt eine Vorrichtung zum Überwachen bzw. Modifizieren von Bremsdrücken die im wesentlichen eine erste Ermittlungseinheit 30 zum Ermitteln einer Verzögerungsvorgabe und eine zweite Ermittlungseinheit 31 zum Ermitteln von Korrekturwerten für Bremsdrücke aufweist. Die Überwachung erfolgt über eine Ähnlichkeitsbetrachtung von der vom Fahrer über das Bremspedal vorgegebenen Fahrzeugverzögerung und der Fahrzeugreaktion, vorzugsweise der tatsächlichen Fahrzeugverzögerung. Es wird dabei die Situation betrachtet, bei der der Fahrer mittels aktivem hydraulischen Bremsdruckaufbau (OHB-V) unterstützt wird. Die vom Fahrer initiierte Verzögerungsvorgabe wird aus dem mit einem Drucksensor gemessenen Druck der Betätigungseinheit, der mit einem Verstärkungsfaktor multipliziert wird, ermittelt. Der Verstärkungsfaktor resultiert aus der hydraulischen Bremskraftverstärkung der Fahrervorgabe. Der verstärkte Druck der Betätigungseinheit ist der angeforderte Druck (Req_Press) . Die Betätigungseinheit kann beispielsweise ein Tandem- Hauptzylinder (THZ) sein. Dieser Wert 10 wird in einem Multiplizierer 11 mit einem Faktor A multipliziert, so dass man eine Verzögerungsvorgabe (Req_VEHACC) als1 shows a device for monitoring or modifying brake pressures, which essentially has a first determination unit 30 for determining a deceleration specification and a second determination unit 31 for determining correction values for brake pressures. The monitoring is carried out via a similarity analysis of the vehicle deceleration specified by the driver via the brake pedal and the vehicle reaction, preferably the actual vehicle deceleration. The situation is considered in which the driver is supported by active hydraulic brake pressure build-up (OHB-V). The deceleration specification initiated by the driver is determined from the pressure of the actuation unit measured with a pressure sensor, which is multiplied by a gain factor. The gain factor results from the hydraulic brake force boost of the driver's specification. The increased pressure of the actuation unit is the requested pressure (Req_Press). The actuating unit can be a tandem master cylinder (THZ), for example. This value 10 is multiplied by a factor A in a multiplier 11, so that a delay specification (Req_VEHACC) is considered
BESTATIGUNGSKOPIE Ausgangssignal erhält. Das zweite Signal 13, welches zu dem Vergleich in dem Vergleicher 12 herangezogen wird, ist das Fahrzeugverzögerungssignal (VEHACC) . Dies kann modellbasiert ermittelt oder mit einemBESTATIGUNGSKOPIE Receives output signal. The second signal 13, which is used for the comparison in the comparator 12, is the vehicle deceleration signal (VEHACC). This can be determined based on a model or with a
Beschleunigungssensor gemessen werden. Figur 2.1 zeigt den Signalverlauf während einer kurzen Zeitspanne, die eine für eine Bildung der Verzögerungssignale typische Situation wiedergeben. Der angeforderte Druck ist mit Req_Press, die Verzögerungsvorgabe mit Req_VEHACC und das Fahrzeugverzögerungssignal mit VEACC bezeichnet. Typische Situationen können beim Lösen der Bremse auftreten, wenn das Pedal z.B. durch Fehler des Druckmodells oder der Ventilkennlinien „kleben,, bleibt oder sich ein selbsttätiges Nachbremsen einstellt. Zunächst wird in dem Subtrahierer 12 die Differenz 14 von VEHACC und Req_VEHACC gebildet. Diese Grosse wird zwei Filtern 15, 16, z.B. Tiefpassfiltern, mit unterschiedlicher Filterzeitkonstante (F_Fast, F_Slow) zugeführt. Die Filter sind bevorzugt von lter oder 2ter Ordnung, die Grenzfrequenzen sind 1 Hz, bzw 15 Hz. Auf diese Weise entsteht, wie Fig. 2.2 zeigt, ein sich relativ langsam änderndes Differenzsignal 14SF und ein auch die schnelleren Änderungen wiedergebendes Differenzsignal 14FF. Bildet man nun in einem weiteren Subtrahierer 18 die Differenz 17 aus F_Fast- F_Slow kann an der Grosse der Differenz 17 (DIFF) die Abweichung der Fahrzeugreaktion (VEHACC) von der Fahrervorgabe (Req_ VEHACC) detektiert werden. Die Grosse der Abweichung 17 wird in einem Tiefpassfilter 22 gefiltert. In Fig. 2.3 sind das Signal 17 und das gefilterte Signal 17F dargestellt .Vom Eingangssignal 17F wird der Schwellwert S abgezogen, Block 19. Das Ausgangssignal 19A wird auf Werte >0 begrenzt.Accelerometer can be measured. FIG. 2.1 shows the signal curve over a short period of time, which represents a situation typical for the formation of the delay signals. The requested pressure is labeled Req_Press, the deceleration specification with Req_VEHACC and the vehicle deceleration signal with VEACC. Typical situations can occur when the brake is released, for example if the pedal sticks, for example due to errors in the pressure model or the valve characteristics, or automatic braking occurs. First, the difference 14 of VEHACC and Req_VEHACC is formed in the subtractor 12. This variable is fed to two filters 15, 16, for example low-pass filters, with different filter time constants (F_Fast, F_Slow). The filters are preferably of the first or second order, the cutoff frequencies are 1 Hz or 15 Hz. In this way, as shown in FIG. 2.2, a relatively slowly changing differential signal 14 SF and a differential signal 14 FF which also reflects the faster changes are produced. If the difference 17 from F_Fast-F_Slow is now formed in a further subtractor 18, the deviation of the vehicle reaction (VEHACC) from the driver specification (Req_ VEHACC) can be detected from the size of the difference 17 (DIFF). The size of the deviation 17 is filtered in a low-pass filter 22. The signal 17 and the filtered signal 17F are shown in FIG. 2.3. The threshold value S is determined by the input signal 17F subtracted, block 19. The output signal 19A is limited to values> 0.
Nach der Multiplikation des Ausgangssignals 19A in einem Multiplizierer 20 mit Faktoren B wird das Ausgangssignal 21 zur Korrektur des Druckmodells und damit letztendlich der Stromeinstellung des analogen Trennventils herangezogen werden.After the output signal 19A has been multiplied in a multiplier 20 by factors B, the output signal 21 will be used to correct the pressure model and thus ultimately the current setting of the analog isolating valve.
Da Änderungen im Fahrzeugverhalten die durch Veränderungen der Fahrwiderstände (z.B. Bergfahrt) hervorgerufen werden, im Vergleich zu einer vom Fahrer eingesteuerten Bremsdruckveränderung langsam entstehen, führt dies nicht zu einer hinreichend großen DIFF Bildung (Strom wird nicht korrigiert) . Abweichungen die konstant sind, werden ebenfalls nicht in DIFF abgebildet. Dies hat den Vorteil, daß diese „Fehleinstellung,, nicht detektiert und somit auch nicht korrigiert wird, da die Einstellung (Req_VEHACC) vom Fahrer nicht verändert wird und als akzeptiert angesehen werden kann. Since changes in vehicle behavior caused by changes in driving resistance (e.g. driving uphill) slowly occur in comparison to a brake pressure change controlled by the driver, this does not lead to a sufficiently large DIFF formation (current is not corrected). Deviations that are constant are also not shown in DIFF. This has the advantage that this “incorrect setting” is not detected and therefore also not corrected, since the setting (Req_VEHACC) is not changed by the driver and can be regarded as accepted.
Claims
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10206343.5 | 2002-02-14 | ||
| DE10206343 | 2002-02-14 | ||
| DE10227740.0 | 2002-06-21 | ||
| DE10227740A DE10227740A1 (en) | 2002-02-14 | 2002-06-21 | Method and device for monitoring and / or modifying brake pressures |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2003068575A1 true WO2003068575A1 (en) | 2003-08-21 |
Family
ID=27735677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2003/001435 Ceased WO2003068575A1 (en) | 2002-02-14 | 2003-02-13 | Method and device for monitoring and/or modifying brake pressures |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2003068575A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011007510A1 (en) * | 2011-04-15 | 2012-10-18 | Continental Teves Ag & Co. Ohg | Method for automatic speed control of motor vehicle, involves adjusting brake pressure in one of brake circuits by adjusting valve characteristic of brake pressure-regulating valve, to correct deviation from desired driving course |
| DE102011084781A1 (en) * | 2011-10-19 | 2013-04-25 | Bayerische Motoren Werke Aktiengesellschaft | Method for ensuring braking effect of vehicle-mounted brake actuators, involves controlling brake operation with predetermined deceleration, independently of driver, for regulating brake pressure, when activation condition is satisfied |
| EP2529987A4 (en) * | 2010-01-25 | 2013-11-20 | Toyota Motor Co Ltd | BRAKE CONTROL DEVICE AND BRAKE DEVICE |
| US9821781B1 (en) | 2016-09-30 | 2017-11-21 | Ford Global Technologies, Llc | Methods and apparatus to control braking of a vehicle during low deceleration operations |
| CN118478847A (en) * | 2024-07-15 | 2024-08-13 | 格陆博科技有限公司 | Energy recovery method based on automatic emergency braking of vehicle |
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| EP2529987A4 (en) * | 2010-01-25 | 2013-11-20 | Toyota Motor Co Ltd | BRAKE CONTROL DEVICE AND BRAKE DEVICE |
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| DE102011084781A1 (en) * | 2011-10-19 | 2013-04-25 | Bayerische Motoren Werke Aktiengesellschaft | Method for ensuring braking effect of vehicle-mounted brake actuators, involves controlling brake operation with predetermined deceleration, independently of driver, for regulating brake pressure, when activation condition is satisfied |
| US9821781B1 (en) | 2016-09-30 | 2017-11-21 | Ford Global Technologies, Llc | Methods and apparatus to control braking of a vehicle during low deceleration operations |
| CN118478847A (en) * | 2024-07-15 | 2024-08-13 | 格陆博科技有限公司 | Energy recovery method based on automatic emergency braking of vehicle |
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