DE102019111491A1 - Method for regulating a spring and / or damper system of a vehicle and a spring and / or damper system of a vehicle - Google Patents

Abstract

The invention relates to a method for regulating a spring and / or damper system of a vehicle during braking with an activated anti-lock control or with an activated anti-slip control of the vehicle, the spring and / or damper system on at least one first characteristic in a hard setting and on at least one second characteristic curve can be operated in a soft setting and the spring and / or damper system is switched to one of the characteristic curves as a function of a detected amount of the current longitudinal slip, so that a deviation of the amount of the current longitudinal slip from a predetermined optimal longitudinal slip is reduced.

Description

The invention relates to a method for regulating a spring and damper system of a vehicle and a spring and damper system of a vehicle according to the preamble of claim 1 and the independent claim 8. For the prior art, reference is made to, for example DE 39 39 292 A1 , the DE 38 37 863 A1 as well as the DE 41 40 270 A1 referenced.

Different control systems are known from the prior art, which control a chassis setting, in particular a spring and damper setting, as a function of vehicle stability parameters.
As is well known, an anti-lock braking system (ABS system for short) regulates the brake slip in order to prevent the wheels from locking when the brakes are applied hard and thus maintain steerability and shorten braking distances. The regulation aims at setting the optimum wheel slip at which the coefficient of friction (with a transferable longitudinal force and a wheel contact force) between the road and the tire is maximum and the deceleration is therefore greatest. The process when ABS is activated is also known as ABS braking. The traction control (ASR), also known as automatic slip control, active slip control or traction control, ensures that the wheels do not spin when the vehicle starts up. The traction control is intended to prevent one or more wheels from spinning and the vehicle swerving sideways when starting with a lot of gas or on bad surfaces such as ice, snow, gravel, wet cobblestones (little static friction). ASR intervenes when the wheels start to spin when a vehicle starts, i.e. they have little or no grip on the road. If there is a threat of excessive slip of the drive wheels, the drive torque is reduced through targeted braking and / or engine management intervention. The control system, which receives its information from the anti-lock braking system wheel speed sensors, among other things, improves traction and driving stability during the acceleration phase, both on a straight line and when cornering. The process when ASR is activated is also known as ASR acceleration.

In the DE 39 39 292 A1 A composite control system for motor vehicles is proposed, which consists of an active or semi-active chassis control and anti-lock braking system (ABS) and / or traction control (ASR) components that have common sensors and evaluation or control circuits. For this purpose, it is provided that the evaluation circuits determine a safety level and that the control circuits emit control signals to the ABS / ASR components and the chassis control as a function of the assessment of these safety levels. In particular, it is described here that during the ABS or ASR control phases, the damper force adjustments must always be made in such a way that minimal wheel load fluctuations occur.

Furthermore, in the DE 38 37 863 A1 describes a suspension system for vehicles in which the adjustment of the shock absorbers are carried out in such a way that the difference between the damping coefficient for the pull stroke and the damping coefficient for the pressure stroke is changed. Due to constant short-stroke vibrations of the wheels, caused by unevenness in the roadway, the respective damper generates a force acting on the body, the mass of which depends on the difference. Due to the different damping coefficients in the direction of tension and compression, resulting forces can be generated in one direction if the damper is moved in rapid succession in alternating directions in tension and compression.

The EP 05 45 130 B1 is based on the idea that for the shortest possible braking distance in a given driving condition (bumpy road, driving maneuvers), it is necessary to guarantee the greatest possible dynamic wheel load. When a vehicle deceleration or vehicle acceleration is detected, for example by evaluating the differentiated driving speed signal, the controller parameters of the Chassis control system adjusted so that the normal force for the respective driving condition is influenced in the direction of the greatest possible value. A braking distance that is optimized under the respective driving conditions can thus be achieved. On the one hand, this system has the disadvantage that the wheel load has to be calculated in a complex manner.

The exchange of information between the driving stability systems (such as an ABS system in particular) and the vertical dynamics systems (such as a spring and damper system in particular) is very limited, so that, for example, only the information is output to the vertical dynamics systems with regard to ABS control whether the ABS control is active or not. Other (potentially usable) parameters that are recorded and calculated by the ABS control have not yet been transferred to the vertical dynamics systems. This either leads to complex computing and sensor systems for recording the driving stability parameters or to a deficit in driving stability, in particular with regard to a possible Minimization of a reduced braking distance with active ABS control.

It is therefore the object of the invention to show a method of a spring and / or damper system of a vehicle and a spring and / or damper system of a vehicle in which the braking distance is optimized during an anti-lock control (ABS control for short).

The object is achieved by a method for regulating a spring and / or damper system of a vehicle with the features of claim 1 and by a spring and / or damper system with the features of the independent claim 9. Advantageous training and development are content of the subclaims.

The invention relates to a method for regulating a spring and / or damper system of a vehicle. The spring and / or damper system is what is known as an actively (or semi-active) regulated spring and / or damper system.
Particularly preferably, it is a hydraulic-mechanical damper in the form of the so-called telescopic shock absorber, since this represents the optimum because of its small dimensions, low friction, precise damping and simple design. These hydraulic shock absorbers preferably consist essentially of an oil-filled cylinder and a piston rod with piston guided therein. When the piston rod (and thus the piston) moves axially in relation to the cylinder, the oil must flow through narrow channels and valves in the piston. The resistance that the oil is presented with creates pressure differences that generate the damping forces via the active surfaces. The damper can be a twin-tube damper or a single-tube damper. In a so-called pressure stage, the piston rod retracts and part of the oil flows from the lower working chamber through the piston valve into the upper working chamber. In the rebound stage, the piston rod extends again.
In a preferred active or semi-active shock absorber, the valves are actively controlled electronically. This enables the damper properties to be set depending on the situation and the desired operating point.

As an alternative to the hydraulic shock absorber mentioned, another type of active spring and / or damper system is also conceivable. It is only necessary that the spring and / or damper system is able to adjust individually to the situation at any time, to provide a force in order to increase or decrease the contact force of the tires or the wheel.

It is provided that during braking with activated anti-lock control (i.e. during so-called ABS braking) or during acceleration with activated anti-slip control (i.e. during so-called ASR acceleration), the spring and / or damper system (hereinafter only more abbreviated as the damper system) is switched to different spring or damper characteristics. This switching to the different characteristics takes place as a function of a wheel slip detected during ABS braking or ASR acceleration. In the following, the acceleration or braking slip are collectively referred to as longitudinal slip or wheel slip.
Depending on whether the current intervention of the stability control is ABS braking or ASR acceleration, the longitudinal slip is either positive or negative, which is why in the case of this regulation the amount of the longitudinal slip is always used as the detection variable.
The wheel slip or the longitudinal slip can be passed on to the damper system through suitable communication between the control units of the individual control systems in the vehicle and can thus be easily recorded and included in the control of the damper system.

The aim is to regulate the damper system by setting a specified or calculated characteristic curve in certain wheel slip situations during ABS braking or ASR acceleration in such a way that the change in wheel slip over time is reduced and the (amount of = wheel slip close to a The wheel load can be changed by changing the damper characteristic. The wheel load is directly related to the slip of the vehicle. The optimal wheel slip value is the coefficient of friction (which results from the transmitted longitudinal force and the wheel contact force or the wheel load ) maximum between the road and the tire, which is why the deceleration is greatest when braking. The optimal wheel slip value then enables, in particular, a shortening of the braking distance or, depending on the situation, a safer ASR acceleration.

The damper system is preferably switched to one of two specified characteristic curves, depending on the situation and the currently detected slip (i.e. the amount of slip). In the first characteristic, the damper system is operated on a "hard" characteristic. For an active spring and / or damper system that can provide a force, this means that the upright force of the tire is increased. For a semi-active hydraulic (or hydraulic-mechanical) damper, two more cases must be distinguished, which are described in more detail below. Is that In contrast, the damper system in the second characteristic line is operated on a "soft" characteristic line. A distinction is again made between two further case constellations for a preferred hydraulic damper system mentioned.

By specifically setting one of the at least two characteristic curves (hard or soft) depending on the current amount of slip, slip fluctuations during ABS braking or during ASR acceleration can be reduced and a deviation of the current slip from the optimal brake slip (temporally ) or acceleration slip can be reduced.

• Wird erfasst, dass der Betrag des aktuellen Brems- bzw. Beschleunigungsschlupfes größer oder gleich ist als der hinterlegte optimale Brems- bzw. Beschleunigungsschlupf, so wird das Dämpfersystem auf die erste (also die „harte“) Kennlinie geschaltet. Abhängig von der Dämpferbewegung wird so die Aufstandskraft beeinflusst. Dadurch werden die Aufstandskraft und damit die Radlast zeitweise erhöht und der Radschlupf im Betrag verringert.
• Wird dagegen erfasst, dass der Betrag des aktuellen Radschlupfes kleiner ist, als der hinterlegte optimale Radschlupf, so wird keine zusätzliche Aufstandskraft benötigt und das Dämpfersystem wird auf die zweite (die „weiche“) Kennlinie geschaltet. Eine mögliche auftretende Nickschwingung des Fahrzeugaufbaus wird durch eine „harte Kennlinie“ in Zugrichtung unterbunden. Hierdurch wird eine Schwankung der Radlast durch eine Nickschwingung des Fahrzeuges reduziert.

In a first preferred embodiment, it is a (semi) active spring and / or damper system, which is situationally able to increase or decrease a (contact) force on the tire (by setting a force) . In a first step, ABS braking or ASR acceleration of the vehicle is recorded. Furthermore, an optimal slip value of the tire is stored and defined in the system. Then the amount of the current brake slip or acceleration slip of the respective tire of the vehicle is recorded. There are two preferred variants:

• If it is detected that the amount of the current braking or acceleration slip is greater than or equal to the stored optimum braking or acceleration slip, the damper system is switched to the first (ie the "hard") characteristic. The contact force is influenced depending on the damper movement. This temporarily increases the vertical force and thus the wheel load and reduces the amount of wheel slip.
• If, on the other hand, it is detected that the amount of the current wheel slip is less than the stored optimum wheel slip, no additional contact force is required and the damper system is switched to the second (the "soft") characteristic. A possible pitching oscillation of the vehicle body is prevented by a "hard characteristic" in the direction of pull. This reduces a fluctuation in the wheel load caused by a pitching vibration of the vehicle.

The damper control depending on the amount of the current slip in a preferred active or semi-active hydraulic (or hydraulic-mechanical) damper system based on one of the two characteristics mentioned, is particularly preferred depending on the current direction of movement of the damper. The characteristic curve setting while the hydraulic spring or damper system is in a compression stage (or in a compression movement) is different from the characteristic curve setting while the hydraulic spring or damper system is in a rebound stage (or in a rebound movement). More detailed embodiments can be found in the description of the figures.

It is furthermore preferably provided that in particular the first characteristic curve (that is to say the “hard” characteristic curve) is limited to a calculated “critical damping” depending on the situation. For this purpose, the first characteristic curve is established on the basis of a continuously calculated critical damping. The critical damping designates a damping characteristic or a damping value from which, if exceeded, the vehicle goes into so-called overdamping. In the worst case, especially when driving on rough roads, contact between the tire and the road surface can be lost if overdamping occurs. In order to prevent the tire from lifting off the road in this way and to ensure contact between tire and wheel at all times, the first characteristic curve is preferably limited to the critical damping calculated on a situation-specific basis.

These and other features emerge from the claims and the description also from the drawings, with the individual features being implemented individually or in combination in the form of sub-combinations in one embodiment of the invention and representing advantageous and individually protectable designs for which protection is claimed here.

• 1 zeigt dabei zwei Diagramme, wobei in das erste Diagramm den Verlauf des Bremsschlupfes des Fahrzeugrads in Abhängigkeit der Zeit aufzeigt, während das zweite Diagramm parallel zum ersten Diagramm die Kennlinienumstellung eines (semi)aktiven Feder- und Dämpfersystems zur gleichen Zeit aufzeigt. Die Kennlinienumstellung ist Beispielhaft und enthält noch keine Abhängigkeit der Bewegungsrichtung des Feder- und Dämpfersystems (Siehe 2 und 3).
• 2 zeigt ein Flussdiagramm zum Ablauf der Dämpfungsregelung auf eine von zwei unterschiedliche Kennlinien in Abhängigkeit von einem vorgegeben optimalen Schlupfwert und von der Position des Dämpfers zum aktuellen Zeitpunkt.
• 3 zeigt ein Flussdiagramm zum Ablauf der Dämpfungsregelung auf eine von zwei unterschiedlichen Kennlinien in Abhängigkeit von zwei vorgegebenen optimalen Schlupfwerten und der zeitlichen Änderung des Bremsschlupfes sowie in Abhängigkeit der Position des Dämpfers zum aktuellen Zeitpunkt.

In the following, the invention is further explained with the aid of three exemplary embodiments. All features described in more detail can be essential to the invention.

• 1 shows two diagrams, the first diagram showing the course of the brake slip of the vehicle wheel as a function of time, while the second diagram shows, parallel to the first diagram, the change in characteristics of a (semi) active spring and damper system at the same time. The change in characteristic curve is an example and does not yet contain any dependency on the direction of movement of the spring and damper system (see 2 and 3 ).
• 2 shows a flowchart for the process of damping control on one of two different characteristic curves depending on a predetermined optimal slip value and on the position of the damper at the current point in time.
• 3 shows a flowchart for the process of damping control on one of two different characteristic curves as a function of two predetermined optimal slip values and the change in brake slip over time as well as depending on the position of the damper at the current point in time.

The invention is explained in more detail below using the example of ABS braking. However, all of the exemplary embodiments mentioned below are also conceivable in the case of ASR acceleration, the current slip λ in each case being in the amount and thus the sign being irrelevant. The terminology "brake slip" alone will then change to "acceleration slip".
1 shows two diagrams. The upper diagram shows an example of the time course of a slip λ that occurs during ABS braking. In addition, the upper diagram shows the optimal brake slip Amax, which remains constant and is stored in the system, at which a maximum braking distance is achieved during ABS braking. In the lower diagram, parallel to the slip from the upper diagram, the temporal (t) course of the regulation of an active spring and / or damper system is shown. "1" describes the first characteristic (ie the "hard" characteristic) while "0" describes the second characteristic (ie the "soft" characteristic). As can be seen when comparing the two diagrams, the (semi) active spring and / or damper system switches to the first, "hard" characteristic curve "1" when the current brake slip λ is greater than the specified optimum brake slip λmax, while the system is detecting a low current brake slip λ than the optimal brake slip λ _max switches to the second, “soft” characteristic “0”. If the current brake slip λ is greater (or equal to) than the optimal brake slip Amax, it is necessary to increase the contact force and to reduce the brake slip λ and to approach the optimal brake slip λ _max . The active spring and / or damper system must therefore actively provide a force in order to increase the wheel load.
Conversely, if the current brake slip λ is less than the stored optimal brake slip Amax, no additional contact force is required. The spring and / or damper system then does not provide any contact force and the system is set to "soft", ie to "0". The characteristic curve setting is switched over at a turning point of the slip oscillation λ. 1 is intended to generally show the functioning of a damper control adapted to the brake slip in a (semi) active spring and / or damper system.

• Wird demnach erfasst, dass der aktuelle Bremsschlupf λ größer oder gleich dem optimalen Bremsschlupf Amax ist, so soll die Aufstandskraft F_z erhöht und damit der Bremsschlupf λ erniedrigt werden. Befindet sich dann das (semi)aktive hydraulische Feder- bzw. Dämpfersystem in einer Druckstufe bzw. in einer Einfederbewegung (ist also die Dämpfergeschwindigkeit v_D negativ) „compression stage“, so wird das Feder- bzw. Dämpfersystem auf die erste, die „harte“ Kennlinie geschaltet. Befindet sich stattdessen das Feder- bzw. Dämpfersystem in einer Zugstufe bzw. in einer Ausfederbewegung (wenn also die Dämpfergeschwindigkeit v_D positiv ist) „rebound stage“, so wird das System auf die zweite, die „weiche“ Kennlinie geschaltet. Dadurch wird die Aufstandskraft F_z in der Druckstufe erhöht und in der Zugstufe nicht reduziert. Insgesamt wird somit der aktuelle Bremsschlupf λ verringert.
• Ist jedoch der aktuelle Bremsschlupf λ kleiner als der hinterlegte optimale Bremsschlupf Amax, so erfolgt die Kennlinienschaltung genau anders herum als soeben erläutert. Da keine zusätzliche Aufstandskraft F_z benötigt wird, wird an dieser Stelle versucht eine mögliche Nickschwingung des Fahrzeugaufbaus zu vermeiden. Hierzu wird das Feder- bzw. Dämpfersystem in einer Druckstufe bzw. bei einer Einfederbewegung „compression stage“ (v_D < 0) auf die zweite, die „weiche“ Kennlinie geschaltet. Befindet sich das System dagegen in einer Zugstufe bzw. in einer Ausfederbewegung „rebound stage“ (v_D > 0) so wird es auf die erste, die „harte“ Kennlinie geschaltet. Eine Nickschwingung des Fahrzeugaufbaus kann vorteilhaft unterbunden werden.

In 2 the process of setting the characteristic curve for an active (or semi-active) hydraulic spring or damping system is shown in particular. The two characteristics are set differently in a hydraulic spring or damping system depending on whether it is in a compression (compression) or a rebound (rebound) stage:

• If it is detected accordingly that the current brake slip λ is greater than or equal to the optimal brake slip Amax, then the contact force F _{z should be} increased and thus the brake slip λ should be reduced. If the (semi) active hydraulic spring or damper system is then in a compression stage or in a compression movement (if the damper speed v _{D is} negative) "compression stage", the spring or damper system is switched to the first, the " hard “characteristic switched. If instead the spring or damper system is in a rebound stage or in a rebound movement (ie if the damper speed v _{D is} positive) “rebound stage”, the system is switched to the second, the “soft” characteristic. As a result, the contact force F _{z is increased} in the compression stage and not reduced in the rebound stage. Overall, the current brake slip λ is thus reduced.
• However, if the current brake slip λ is less than the stored optimum brake slip Amax, the characteristic curve is switched exactly the other way around than just explained. Since no additional contact force F _{z is} required, an attempt is made at this point to avoid a possible pitching oscillation of the vehicle body. For this purpose, the spring or damper system is switched to the second, the “soft” characteristic curve in a compression stage or in the event of a “compression stage” movement (v _D <0). If, on the other hand, the system is in a rebound stage or in a rebound movement “rebound stage” (v _D > 0), it is switched to the first, the “hard” characteristic curve. A pitching vibration of the vehicle body can advantageously be prevented.

• Im ersten Fall, ist der aktuelle Bremsschlupf λ kleiner als der hinterlegte minimale Bremsschlupf λ_min. Die Aufstandskraft F_Z muss also in diesem Falle nicht erhöht werden. Vielmehr soll eine Nickschwingung des Fahrzeugaufbaus vermieden werden. Hierzu wird das Feder- bzw. Dämpfersystem in einer Druckstufe bzw. bei einer Einfederbewegung „compression stage“ (v_D < 0) auf die zweite, die „weiche“ Kennlinie geschaltet. Befindet sich das System dagegen in einer Zugstufe bzw. in einer Ausfederbewegung „rebound stage“ (v_D > 0) so wird es auf die erste, die „harte“ Kennlinie geschaltet. Eine Nickschwingung des Fahrzeugaufbaus kann vorteilhaft unterbunden werden.
• Im zweiten Fall ist der aktuelle Bremsschlupf λ größer (oder gleich) als der hinterlegte maximale Bremsschlupf Amax. In diesem Falle soll die Aufstandskraft F_z erhöht werden, um den aktuellen Bremsschlupf λ zu verringern. Befindet sich dann das aktive hydraulische Feder- bzw. Dämpfersystem in einer Druckstufe bzw. in einer Einfederbewegung (ist also die Dämpfergeschwindigkeit v_D negativ) „compression stage“, so wird das Feder- bzw. Dämpfersystem auf die erste, die „harte“ Kennlinie geschaltet. Befindet sich stattdessen das Feder- bzw. Dämpfersystem in einer Zugstufe bzw. in einer Ausfederbewegung (wenn also die Dämpfergeschwindigkeit v_D positiv ist) „rebound stage“, so wird das System auf die zweite, die „weiche“ Kennlinie geschaltet. Dadurch wird so die Aufstandskraft F_z in der Durckstufe erhöht und in der Zugstufe nicht reduziert. Insgesamt wird somit der aktuelle Bremsschlupf λ verringert.
• Im dritten Fall befindet sich der aktuelle Bremsschlupf λ zwischen dem maximalen λ_max und dem minimalen λ_min Bremsschlupf. An dieser Stelle wird erneut eine Fallunterscheidung durchgeführt in welcher betrachtet wird, ob der Bremsschlupf im Laufe der Zeit zu oder abnimmt bzw. welche Bremsschlupfänderung Δλ erfolgt ist.
• Ist demnach die Bremsschlupfänderung Δλ bzw. der Gradient des Bremsschlupfes Δλ positiv (hat der Bremsschlupf λ also zugenommen), so ist es vorgesehen, dass die Kennlinienschaltung gemäß dem ersten Fall erfolgt. Die Aufstandskraft F_Z muss also in diesem Falle nicht erhöht werden. Vielmehr soll eine Nickschwingung des Fahrzeugaufbaus vermieden werden. Hierzu wird das Feder- bzw. Dämpfersystem in einer Druckstufe bzw. bei einer Einfederbewegung „compression stage“ (v_D < 0) auf die zweite, die „weiche“ Kennlinie geschaltet. Befindet sich das System dagegen in einer Zugstufe bzw. in einer Ausfederbewegung „rebound stage“ (v_D > 0) so wird es auf die erste, die „harte“ Kennlinie geschaltet. Eine Nickschwingung des Fahrzeugaufbaus kann vorteilhaft unterbunden werden.
• Ist die Bremsschlupfänderung Δλ bzw. der Gradient des Bremsschlupfes Δλ negativ (hat der Bremsschlupf λ also abgenommen), so ist es vorgesehen, dass die Kennlinienschaltung gemäß dem zweiten Fall erfolgt. In diesem Falle soll die Aufstandskraft F_z erhöht werden, um den aktuellen Bremsschlupf λ zu verringern. Befindet sich dann das (semi)aktive hydraulische Feder- bzw. Dämpfersystem in einer Druckstufe bzw. in einer Einfederbewegung (ist also die Dämpfergeschwindigkeit v_D negativ) „compression stage“, so wird das Feder- bzw. Dämpfersystem auf die erste, die „harte“ Kennlinie geschaltet. Befindet sich stattdessen das Feder- bzw. Dämpfersystem in einer Zugstufe bzw. in einer Ausfederbewegung (wenn also die Dämpfergeschwindigkeit v_D positiv ist) „rebound stage“, so wird das System auf die zweite, die „weiche“ Kennlinie geschaltet. Dadurch wird so die Aufstandskraft F_z in der Druckstufe erhöht und in der Zugstufe nicht reduziert. Insgesamt wird somit der aktuelle Bremsschlupf λ verringert.
• Im Gegensatz zur Ausführungsform aus 2, besitzt die dritte Ausführungsform aus 3 einen zeitlichen Vorteil. So ist es bei der dritten Ausführungsform möglich, die Kennlinienschaltung bereits vor einem Über- oder Unterschreiten des maximalen oder minimalen Bremsschlupfes λ_max, Amin zu regeln. Dies ermöglicht, dass die Amplitude der Schlupfschwingung λ noch weiter verringert werden kann und sich dem optimalen Bremsschlupf annähern.

In 3 is an expanded embodiment of the execution 2 shown. The optimal slip value λmax (as from the exemplary embodiment of 2 ) divided into two limit values, an upper maximum λmax and a lower minimum λ _min brake slip value and these are stored in the system. The upper maximum brake slip λ _max is preferably at least approximately 6.0%, while the lower minimum brake slip Amin is at least approximately 4.9%. These slip thresholds or limit values relate to the control strategy of the spring and / or damper system and not to the control strategy of the ABS control. In addition, the change in slip Δλ, viewed over time, is included in the characteristic control. Three groups of cases can be distinguished:

• In the first case, the current brake slip λ is less than the stored minimum brake slip λ _min . The contact force F _Z does not have to be increased in this case. Much more a pitching oscillation of the vehicle body is to be avoided. For this purpose, the spring or damper system is switched to the second, the “soft” characteristic curve in a compression stage or in the event of a “compression stage” movement (v _D <0). If, on the other hand, the system is in a rebound stage or in a rebound movement “rebound stage” (v _D > 0), it is switched to the first, the “hard” characteristic curve. A pitching vibration of the vehicle body can advantageously be prevented.
• In the second case, the current brake slip λ is greater than (or equal to) than the stored maximum brake slip Amax. In this case, the contact force F _{z should be} increased in order to reduce the current brake slip λ. If the active hydraulic spring or damper system is then in a compression stage or in a compression movement (ie if the damper speed v _{D is} negative) "compression stage", the spring or damper system changes to the first, the "hard" characteristic switched. If instead the spring or damper system is in a rebound stage or in a rebound movement (ie if the damper speed v _{D is} positive) “rebound stage”, the system is switched to the second, the “soft” characteristic. As a result, the contact force F _{z is increased} in the pressure stage and not reduced in the rebound stage. Overall, the current brake slip λ is thus reduced.
• In the third case, the current brake slip λ is between the maximum λ _max and the minimum λ _min brake slip. At this point, a case distinction is again carried out in which it is considered whether the brake slip increases or decreases over time or which brake slip change Δλ has occurred.
• If accordingly the change in brake slip Δλ or the gradient of the brake slip Δλ is positive (that is, if the brake slip λ has increased), it is provided that the characteristic curve is switched according to the first case. The contact force F _Z does not have to be increased in this case. Rather, a pitching oscillation of the vehicle body should be avoided. For this purpose, the spring or damper system is switched to the second, the “soft” characteristic curve in a compression stage or in the event of a “compression stage” movement (v _D <0). If, on the other hand, the system is in a rebound stage or in a rebound movement “rebound stage” (v _D > 0), it is switched to the first, the “hard” characteristic curve. A pitching vibration of the vehicle body can advantageously be prevented.
• If the change in brake slip Δλ or the gradient of the brake slip Δλ is negative (that is, if the brake slip λ has decreased), it is provided that the characteristic curve is switched according to the second case. In this case the contact force F _{z should be} increased in order to reduce the current brake slip λ. If the (semi) active hydraulic spring or damper system is then in a compression stage or in a compression movement (if the damper speed v _{D is} negative) "compression stage", the spring or damper system is switched to the first, the " hard “characteristic switched. If instead the spring or damper system is in a rebound stage or in a rebound movement (ie if the damper speed v _{D is} positive) “rebound stage”, the system is switched to the second, the “soft” characteristic. As a result, the contact force F _{z is increased} in the compression stage and not reduced in the rebound stage. Overall, the current brake slip λ is thus reduced.
• In contrast to the embodiment 2 , the third embodiment possesses 3 a time advantage. In the third embodiment, for example, it is possible to regulate the characteristic curve circuit before the maximum or minimum brake slip λ _max , Amin is exceeded or not reached. This enables the amplitude of the slip oscillation λ to be reduced even further and to approach the optimal brake slip.

As already explained above, it is possible to limit the characteristic curves of the exemplary embodiments (in particular the first, the “hard” characteristic curve) to a “critical damping”. In this way, permanent contact of the tire with the roadway can advantageously be guaranteed and driving safety can be increased.

The cited invention enables positive support during ABS braking or during ASR acceleration. In particular in the case of ABS braking, the braking distance can be significantly shortened by the aforementioned invention.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 3939292 A1 [0001, 0003]
• DE 3837863 A1 [0001, 0004]
• DE 4140270 A1 [0001]
• EP 0545130 B1 [0005]

Claims (11)

Method for regulating a spring and / or damper system of a vehicle during braking with an activated anti-lock control or with an activated anti-slip control of the vehicle, the spring and / or damper system on at least one first characteristic curve (“1”) in a hard setting and can be operated on at least one second characteristic curve (“0”) in a soft setting, characterized in that the spring and / or damper system is switched to one of the characteristic curves (“1”) depending on a detected amount of the current longitudinal slip (λ) so that a deviation of the amount of the current longitudinal slip (λ) from a given optimal longitudinal slip (Amax) is reduced. Procedure according to Claim 1 Wherein upon detecting an activated anti-skid control or an activated traction control of the vehicle, an optimal longitudinal slip (λ _max) is determined and wherein • Upon detection of a greater amount of the current longitudinal slip (λ) than the predetermined optimum longitudinal slip (λ _max), the spring and / or the damper system is switched to the first characteristic curve ("1") and where • When a lower amount of the current longitudinal slip (λ) is recorded than the specified optimum longitudinal slip (λ _max ), the spring and / or damper system is switched to the second characteristic curve ( "0") is switched. Method according to one of the preceding claims, wherein the characteristic curve setting of the spring and / or damper system takes place differently depending on the current direction of movement of the damper, either in a compression stage or a rebound stage. Procedure according to Claim 2 or 3 , where • when a current longitudinal slip (λ) is detected that is lower than the specified optimum longitudinal slip (λ _max ), the spring and / or damper system in a rebound stage on the first characteristic curve ("1") and in a compression stage on the second characteristic curve ( "0") is switched and where • when a current longitudinal slip (λ) greater than the specified optimum longitudinal slip (λ _max ) is detected, the spring and / or damper system is switched to the second characteristic curve ("0") in a rebound stage and in one Pressure stage is switched to the first characteristic curve ("1"). Method according to one of the preceding claims, wherein when an activated anti-lock control or an activated anti-slip control of the vehicle is detected, an upper maximum (λ _max ) and a lower minimum (λ _min ) to be achieved longitudinal slip and a temporal change (Δλ) of the amount of the current Longitudinal slip (λ) is recorded, where • when a lower amount of the current longitudinal slip (λ) is recorded than the specified minimum longitudinal slip (λ _min ), the spring and / or damper system is switched to the second characteristic ("0") and where • when a larger amount of the current longitudinal slip (λ) is detected than the specified maximum longitudinal slip (λ _max ), the spring and / or damper system is switched to the first characteristic ("1") and where • when an amount of the current longitudinal slip is detected (λ), which lies between the specified maximum (λ _min ) and minimum longitudinal slip (λ _max ), where the amount of longitudinal slip (Δλ) increases over a specified time interval, the spring and / or damper system is switched to the second characteristic curve ("0") and where • when an amount of the current longitudinal slip (λ) is recorded that is between the specified maximum (λ _max ) and minimum ( λ _min ) longitudinal slip, whereby the amount of longitudinal slip (Δλ) decreases over a defined time interval, the spring and / or damper system is switched to the first characteristic ("1"). Procedure according to Claim 5 , whereby the characteristic curve setting of the spring and / or damper system takes place differently depending on the current direction of movement of the damper, either in a compression stage or in a rebound stage and where • when a lower amount of the current longitudinal slip (λ) than the specified minimum longitudinal slip (λ _min ), the spring and / or damper system is switched to the first characteristic curve ("1") in a rebound stage and to the second characteristic curve ("0") in a compression stage and where • when a larger amount of the current longitudinal slip (λ) is detected as the specified maximum longitudinal slip (λ _max ), the spring and / or damper system is switched to the second characteristic curve ("0") in a rebound stage and to the first characteristic curve ("1") in a compression stage and where • when a current amount of the longitudinal slip (λ), which lies between the specified maximum (λ _max ) and minimum (λ _min ) longitudinal slip, the amount of longitudinal slip (Δλ) over a fixed gel egten time interval increases, the spring and / or damper system is switched to the first characteristic curve ("1") in a rebound stage and to the second characteristic curve ("0") in a compression stage and where • when an amount of the current longitudinal slip (λ ), which lies between the specified maximum (λ _max ) and minimum (λ _min ) longitudinal slip, with the amount of longitudinal slip (Δλ) decreasing over a specified time interval, the spring and / or damper system in a rebound stage on the second characteristic curve (" 0 ") and is switched to the first characteristic curve (" 1 ") in a pressure stage. Procedure according to Claim 5 or 6th , whereby the maximum longitudinal slip (λ _max ) is set at 6.0% and the minimum longitudinal slip (λ _min ) at 4.5 to 5.9%. Method according to one of the preceding claims, wherein the first characteristic curve (“1”) is limited to a continuously calculated critical damping. Spring and / or damper system of a vehicle for performing the method according to one of the Claims 1 to 8th , which can be operated during an activated anti-lock control or anti-slip control on a first characteristic ("1") in a hard setting or on a second characteristic ("0") in a soft setting, characterized in that the spring and / or damper system in Dependency of a current amount of a longitudinal slip (λ) is switched to one of the two characteristics (“1”, “0”), so that the change in the longitudinal slip (λ) over time is reduced. Spring and / or damper system according to Claim 8 , the characteristic curve setting of the spring and / or damper system being different in a rebound stage of the damper than in a compression stage of the damper. Spring and / or damper system according to one of the preceding claims, wherein the spring and / or damper system can be actively controlled and / or regulated.

Images