DE102008032545A1 - Influencing device for influencing active chassis system of passenger car, has active stabilizer with active roll stabilization device comprising actuator that serves as chassis actuator - Google Patents

Abstract

The device has a roadway sensor for producing sensor data of a roadway present before a vehicle in driving direction. The roadway serves for determination of a roadway profile. A pilot control unit determines pilot control variables based on the determined profile. The variables are used to adapt an adjustment of a chassis actuator (11) to the determined profile. An input signal for a connection control is calculated based on the variables. An actuator (60) of an active roll stabilization device of an active stabilizer serves as the chassis actuator.

Description

The The invention relates to an influencing device for influencing an active suspension system of a vehicle according to the preamble of claim 1.

From the US Pat. No. 6,233,510 B1 is a method and a generic device for predicting the road condition and for influencing the spring units of the vehicle depending on the predetermined road condition. A sensor-for example a laser sensor or an image recognition sensor-detects the road surface in front of the vehicle and transmits the sensor data to a control unit, which predetermines the roadway profile lying in front of the vehicle in the direction of travel. Depending on this lane profile, the control unit activates an active suspension system with several spring or damper units and controls or regulates the spring rate, the damping rate, the pressure, the level, etc.

outgoing From this it is an object of the present invention the ride comfort for the vehicle occupants continue to improve.

These Task is by an influencing device with the features of claim 1.

The Influencing device has a road sensor, the sensor data from a lane in front of the vehicle in the direction of travel generated, from which a roadway profile can be determined, the a pilot unit is transmitted. The pilot unit determines a pilot control variable depending on the roadway profile, which serves the setting of the suspension actuator, here is formed by a controller of an active stabilizer, to the to adapt the determined roadway profile. Based on the input tax quantity this is an input for a z regulation of the construction position of the vehicle serving bodywork regulation calculated. For example, based on the pilot size input quantity determined for the body control modify a setpoint that can be specified in the body control and thereby adjusting the active suspension system or the vehicle to reach the predetermined roadway profile. The control of Fahragaktuators depends on the roadway profile Consequently, in a body structure to control the building position of the Vehicle body integrated. The chassis actuator is a positioner a roll stabilization device, in particular an active Stabilizer.

Thereby is ensured that outside the sphere of influence the feedforward control or a defective pilot control always sufficient Driving comfort is guaranteed - in such cases the position or movement of the vehicle body still becomes regulated by means of the body control. The superimposed the pilot control Bodywork therefore ensures a very good ride comfort even with errors in the pilot control.

advantageous Further developments of the influencing device according to the invention result from the dependent claims.

advantageously, the pilot control unit determines several separate pilot control variables, in particular a pre-tax level for the regulator of the stabilizer, that for determining a target level of the with the stabilizer connected spring or damper units serves and a Pre-control assembly position, which influences a build-up position controller the bodywork is used. By this measure exist for modifying the body control several degrees of freedom, so that the structure control very easy to predefinable conditions or parameters can be adjusted, such. B. the frequency of the determined by the Road profile known, acting on the vehicle roadway suggestions.

there can at least the pilot level in a modification stage Consideration of given properties of the body control be converted to a modified input tax level and the Determination of the target level associated with the stabilizer Serve spring or damper units. That way is an adjustment of the pilot level to the system limits or dynamic Properties of the body control possible. Especially the modification level is executed as a system dynamics level and determines from the pre-tax level a dynamics-optimized pre-tax level, where the dynamics-optimized pre-control level is the dynamic behavior considered in the active chassis system of the vehicle.

It is also advantageous if the nominal level at the spring or damper units connected to the stabilizer on the basis of the pilot control level and / or a modified pilot control formed therefrom levels and an output variable of the build-up position controller is determined. As a result, a simple adaptation of the target level is possible to the located in front of the vehicle, determined roadway profile.

Thereby, that the pre-control build-up position for correcting a to the build-up position controller returned actual state value the vehicle is used, an improved interaction the body control and the feedforward control can be achieved. Especially can use the build position controller instead of the actual Build-up position corrected by means of the pre-control build-up position Build-up position and / or instead of the actual body vertical velocity one by means of the time derivative of the pilot control position corrected vertical vertical velocity is supplied. Thus, it is ensured that the build-up position controller the change possibly caused by the pre-control not trying to correct in the body position.

It is also advantageous if from the determined roadway profile in a Radbewegungsermittlungsstufe determines a calculated wheel position is transmitted to the pilot unit as an input becomes. In particular, the dynamic properties the vehicle wheel are taken into account. The feedforward control is by considering the calculated wheel position more precisely, whereby a further increase in comfort is achieved. At least One of the pilot control variables can be dependent determined by the calculated wheel position.

It is also advantageous if based on a the road profile descriptive size determines a contour profile which is a position track of several construction positions for describes the drive of the vehicle along the lane profile, the curvature of the contour profile under the boundary condition minimizes that on the spring or damper units maximum available suspension travel can be maintained. This ensures the greatest possible Comfort considering the fact that dependent from the roadway profile not always all road increases or road recesses through the active suspension system without retroactive effect can be balanced on the body position.

It there is a possibility that the bodywork by the input tax quantity or modified input tax quantity is influenced such that the construction position of the vehicle body at Fahrbahnanregungen in a lower frequency range below a lower limit frequency substantially follows the roadway profile. In this lower frequency range, lane profile changes converted into corresponding assembly position changes, whereby a simple implementation option for optimization comfort possible under consideration of system limits is.

The lower limit frequency can be variable and of a Depend on roadway descriptive size, in particular from the determined prepared roadway profile. Further may be the lower limit frequency of the on the spring or damper units depend on maximum available spring travel. In which minimizes the lower limit frequency under the boundary condition is that the maximum on the spring or damper units available spring travel when driving along the can be adhered to in front of the vehicle lying lane profile in a simple way the greatest possible comfort taking into account the system limits, in particular the travel limits, be achieved. The curvature of the contour profile leaves in compliance with the on the spring or damper units maximum available spring travel very easy minimize.

there The bodywork can the construction position of the vehicle body at Road excitations with frequencies above the lower limit frequency settle with the goal, the build-up position essentially unchanged maintain a high level of comfort in the range of frequencies is given above the lower frequency range. road suggestions should not be in the built-up position in this frequency range impact. This applies up to an upper limit frequency of about 8-10 Hz, the dynamic limit of the active suspension system equivalent.

Farther an advantage is the provision of a diagnostic unit based on from a size describing the roadway profile and a size describing the current state of the vehicle a deviation between the expected state of the vehicle and determined the actual, current state of the vehicle. In this way, control errors or even system defects be determined.

The Diagnostic unit determines the expected state of the vehicle for example, on the basis of the determined roadway profile, in particular with the help of a given vehicle model.

There is also the possibility that the diagnostic unit based on the deviation, a correction value determined, which is used to adjust the pilot size and / or the modified pilot size. By this configuration, the influencing device can be adapted to external conditions and z. B. wear conditions of the active suspension system or a changed dynamics of the body control by temperature fluctuations at least partially compensate.

in the Below, the invention with reference to the accompanying drawings explained in more detail. Showing:

1 a schematic representation of a part-vehicle model with wheel, spring or damper unit and vehicle body,

2 a first embodiment of the influencing device in a schematic, block diagram-like representation,

3 a second embodiment of the influencing device in a schematic, block diagram-like representation,

4 a third embodiment of the influencing device in a schematic, block diagram-like representation,

5 a diagnostic unit of the influencing device in a schematic block diagram similar representation and

6 a schematic partial view of a first active suspension system with controllable actuator of an active stabilizer.

In 1 is shown a schematic representation of a part-vehicle model, with a vehicle wheel 10 of this vehicle wheel 10 associated controllable spring or damper unit 11 and the vehicle body shown as a mass 12 , the vehicle's center of gravity 13 having. The part-vehicle model represents only one of the vehicle wheels 10 is relevant part of the entire vehicle and applies, for example, in a car with two axles for each of the four vehicle wheels 10 as well as for the four spring or damper units 11 ,

This sub-vehicle model is based on a stationary coordinate system 14 , With h (s) the actual lane profile of the lane is marked, where the path s is the abscissa of the coordinate system 14 represents and the roadway h (s) is measured in the direction of the vehicle vertical axis. The wheel position of the vehicle wheel 10 in the direction of the vehicle vertical axis is denoted as r and the construction position of the vehicle center of gravity 13 seen in the direction of the vehicle vertical axis is provided with the reference numeral z. x is the distance between the construction position z of the vehicle body 12 and the wheel position r of the vehicle wheel 10 and defined here as x = z - r (G1.1)

In 1 Finally, the reference symbol y is the current actual level of the spring or damper unit 11 referred to by the control of a Fahrwerksaktuators 60 is adjustable or changeable, as in 1 is shown schematically and based on 6 is explained in more detail.

The road profile h can for each side of the vehicle and possibly for each vehicle 10 be different. Also the wheel positions r of the vehicle wheels 10 and the actual levels y can be on all spring or damper units 11 or vehicle wheels 10 differ.

About an influencing device 20 can the suspension actuator 110 be controlled to the respective distance x between the construction position z of the vehicle body 12 and the associated vehicle wheel 10 or to influence the respective actual level y.

The influencing or regulation of the construction position z and / or the movement of the vehicle body 12 can be done in three dimensions. Accordingly, the pitch and / or roll and / or the lift, as well as the wheel contact forces of the vehicle wheels on the road surface can be influenced, controlled or regulated. As a result, a tension of the chassis can be achieved, for example, between the front and rear axle of the vehicle, in particular the wheel contact forces of two diagonally opposite vehicle wheels opposite the wheel contact forces of the other two diagonally ge opposite vehicle wheels are increased or decreased. In this way, the lateral dynamic behavior of the vehicle can be influenced.

In 6 is an example of an active suspension system with a roll stabilization device 65 schematically based on the two front vehicle wheels 10 shown in partial view. As a spring or damper unit 11 There are passive spring or damper units 11 intended. Alternatively or additionally, active or semi-active spring or damper units could also be used 11 be used with adjustable springs or dampers.

The roll stabilization device 65 has an active stabilizer 66 on, over the controllable Steller 60 can be actively adjusted. The stabilizer 66 has a torsion bar 67 on, which is rotatably mounted about its longitudinal axis. The torsion bar 67 extends in the vehicle transverse direction and at its two ends in each case a stabilizer arm protrudes 68 transverse - for example, in the vehicle longitudinal direction - of the torsion bar 67 path. The stabilizer arms 68 are at theirs the torsion bar 67 opposite ends 69 with the respective associated spring or damper unit 11 Motion coupled, so that the ends 69 during compression or rebound of the associated spring or damper unit 11 moved. At least that with the stabilizer arm 68 connected part of the torsion bar 67 to the stopper 60 rotated about its longitudinal axis. The actuator is designed as a turntable example, and in particular in the torsion bar 67 integrated and divides this into two stabilizer parts 66a . 66b , Alternatively, other versions are possible, in which each one actuator a force in vehicle height direction on the stabilizer arms 68 exercises.

• – In der geöffneten Schaltstellung sind die beiden Stabilisatorteile 66a, 66b durch den offenen Steller 60 gegeneinander frei drehbar, so dass sich Ein- und Ausfederbewegungen der Feder- oder Dämpfereinheit 11 auf einer Seite nicht auf die andere Feder- oder Dämpfereinheit 11 auswirken.
• – In der geschlossenen Schaltstellung bei nicht angesteuertem Steller 60 koppelt der Steller die beiden Stabilisatorteile 66a, 66b drehfest miteinander, so dass Ein- und Ausfederbewegungen der Feder- oder Dämpfereinheit 11 auf einer Seite über den Stabilisator 66 eine Kraft auf die jeweils andere Feder- oder Dämpfereinheit 11 übertragen. Solange der Steller nicht durch ein Ansteuersignal aktiviert wird, verhält sich die Wankstabilisierungseinrichtung 65 wie eine Wankstabilisierungseinrichtung mit einem passiven Stabilisator ohne Steller.
• – In der geschlossenen Schaltstellung bei durch ein Ansteuersignal aktiviertem Steller 60 verdreht der Steller die beiden Stabilisatorteile 66a, 66b gegeneinander, so dass unabhängig davon, ob eine Ein- oder Ausfederbewegung einer der Feder- oder Dämpfereinheiten 11 vorliegt oder nicht, durch den Steller 60 eine Kraft auf eine oder beide Feder- oder Dämpfereinheiten 11 ausgeübt werden kann. Dadurch kann das Istniveau y an einer oder an beiden Feder- oder Dämpfereinheiten 11 verändert und auf ein Sollniveau y_soll eingestellt werden.

About the choice of the switch position of the actuator 60 may affect an input or rebound movement of one or both of the stabilizer 66 coupled together spring or damper units 11 to be changed:

• - In the open position, the two stabilizer parts 66a . 66b through the open actuator 60 freely rotatable relative to each other, so that compression and rebound movements of the spring or damper unit 11 on one side not on the other spring or damper unit 11 impact.
• - In the closed switch position when the actuator is not activated 60 the adjuster couples the two stabilizer parts 66a . 66b rotatably with each other, so that compression and rebound movements of the spring or damper unit 11 on one side over the stabilizer 66 one force on the other spring or damper unit 11 transfer. As long as the actuator is not activated by a drive signal, the roll stabilization device behaves 65 like a roll stabilizer with a passive stabilizer without a regulator.
• - In the closed switching position with a controller activated by a drive signal 60 The actuator twists the two stabilizer parts 66a . 66b against each other, so that regardless of whether a one or rebound movement of one of the spring or damper units 11 present or not, by the controller 60 a force on one or both spring or damper units 11 can be exercised. As a result, the actual level y at one or both spring or damper units 11 changed and set to a desired level y _should .

Both on the front axle, as well as on the rear axle of the vehicle can be an active stabilizer 66 be provided so that the roll stabilization device 65 one or more active stabilizers 66 can have.

A first embodiment of the influencing device 20 is in 2 shown in the form of a block diagram. The influencing device 20 controls the actuator 60 the roll stabilization device 65 depending on the condition of lying in the direction of travel of the vehicle in front of the vehicle lane. In this way, the chassis of the vehicle can already be adjusted on lying ahead of the vehicle road excitations such as potholes, sleepers, transverse grooves, etc., even before the vehicle has reached the point of the path s with the road surface excitation. For detecting the roadway excitation descriptive roadway profile, the influencing device 20 a road sensor 21 on, the road surface seen in the direction of travel observed in front of the vehicle and the road profile descriptive sensor data d to a data processing unit 22 transmitted.

In the data processing unit 22 the prepared roadway profile h _{L is} determined from the roadway _sensor data d. The data processing unit 22 is to determine the prepared lane profile h _L and the current vehicle longitudinal speed v _x and other state data such as, for. B. the current construction position z or the actual levels y of the spring or damper units 11 fed. Consequently, the position and orientation of the road sensor 21 known, so that an accurate road profile determination is possible. Of Further will be in the data preparation unit 22 Components filtered out by the sensor data d road excitations filtered out with a frequency above a predetermined upper limit frequency, for example, 8-10 Hz. The output signal is from the data conditioning unit 22 provided the prepared roadway profile h _L.

From the prepared roadway profile h _L are in a Radbewegungsermittlungsstufe 23 the resulting vertical wheel movements of the vehicle wheels 10 determined and thus for each vehicle a low-frequency, calculated wheel position r _L determined by the following equation: m R · R .. L = C R (H L - r L ) k R (H L - ṙ L ), (Gl.2) where m _{R is} the mass of the respective vehicle wheel 10 , c _{R is} a Radvertikalfederkonstante, k _{R is} a Radvertikaldämpfungs constant, and ṙ _{L is} the calculated Radvertikalgeschwindigkeit (the time derivative of the calculated wheel position r _L ), r .. _L the calculated Radvertikalbeschleunigung (the time derivative of the calculated Radvertikalgeschwindigkeit ṙ _L ) and ḣ _L the prepared lane profile change (the time derivative of the prepared lane profile h _L ) is.

In an alternative, simple embodiment variant, the calculated wheel position r _{L could} also be the sum of the prepared roadway profile h _L and the radius of the vehicle wheel 10 specified constant, the vertical spring and damping characteristics of the vehicle wheel 10 would be neglected.

The influencing device 20 also has a pilot control unit 24 on, which determines based on the respective calculated wheel position r _L a pilot signal, which then for the regulation of the position or movement of the vehicle body 13 and / or for the regulation of the actual levels y by means of the actuator 60 of the active stabilizer 66 the roll stabilization device 65 is used.

wobei c_F eine Federkonstante der Feder- oder Dämpfereinheit 11, k_F eine Dämpferkonstante der Feder- oder Dämpfereinheit 11 und die berechnete Radvertikalgeschwindigkeit ṙ_L die zeitliche Ableitung der berechneten Radposition r_L ist. Dies gilt unter der Voraussetzung, dass der Fahrzeugaufbau 12 auch bei niederfrequenten Anregungen unterhalb einer unteren Grenzfrequenz von beispielsweise 0,5 Hz in Ruhe verbleiben soll.In the first embodiment of the influencing device 20 is a pre-control signal in each case a pilot control level y _P for each spring unit 11 determined. For the pilot control level y _{P of} the respective vehicle wheel 10 Depending on the active chassis system used, the following relationship follows, for example:

where c _{F is} a spring constant of the spring or damper unit 11 , k _{F is} a damper constant of the spring or damper unit 11 and the calculated vertical wheel speed ṙ _{L is} the time derivative of the calculated wheel position r _L. This is on condition that the vehicle body 12 Even at low frequency suggestions below a lower cutoff frequency of, for example, 0.5 Hz to remain at rest.

From the pilot control level y _P is then in a pilot dynamic filter 25 the filtered pre-control level y _{PL is} formed:

The procedure for determining the filter coefficients a _i and b _{i of} the pilot dynamic filter 25 is known per se from filter design methods and will be briefly explained below.

The filtered pre-control level y _PL is finally to a body control 26 transmitted, which controls the construction position z based on a predetermined construction position setpoint z _soll , in particular, z _soll = constant. This body structure 26 in the preferred embodiment, a skyhook controller 27 and a suspension control 28 on. The skyhook controller 27 becomes the current wheel position r, as well as the current wheel vertical speed ṙ for each of the vehicle wheels 10 and the current construction position z and their time derivative, the current vertical vertical velocity ż given as input variables.

wobei c_S eine Skyhookfederkonstante und k_S eine Skyhookdämpferkonstante ist.The skyhook controller 27 determined from the mentioned input variables for each spring or damper unit 11 a skyhook level y _sk to the vehicle body 12 to bring into its predetermined desired position. Where:

where c _{S is} a skyhook spring constant and k _{S is} a skyhook attenuator constant.

F _e is a skyhook restoring force according to the following relationships: F e = c e x e + k e ẋ e , (Eq.6) where x _{e represents} a synthetic stop with

Δx _max is a skyhook travel limit, c _e is a return spring constant, and k _{e is} a return damper constant, which is dictated by the desired skyhook control response.

From the relevant skyhook level y _sk and the respective filtered pre-control level y _PL is for those with the stabilizer 66 coupled spring or damper units 11 the desired level y _{should be} determined and the suspension control 28 submitted for recruitment: y should = y sk + y PL (Equation 8)

The filter coefficients a _i and b _{i of} the pilot dynamic filter 25 we can be determined as follows: The transmission behavior of the suspension control 28 can be determined by measurements. Thus, it is known which transmission dynamics the pilot control level y _P without the pilot dynamic filter 25 would learn. With the aid of known filter design methods, a filter is designed that is as true to amplitude as possible and does not cause phase delays up to the highest possible frequency. For example, in the simplest case a PD element with a proportional gain KP = 1 can be used.

By integrating the pilot control of the active spring units 11 in the bodywork regulation 26 It is ensured that sufficient driving comfort is always ensured outside the effective range of the feedforward control or in the event of defective pilot control - in such cases, the position or movement of the vehicle body becomes 12 still using the skyhook controller 27 regulated.

In the following, a second embodiment of the influencing device that has been extended compared to the first exemplary embodiment described above will be explained 20 explained. This second embodiment variant has, in addition to the first embodiment, a contour determination unit 40 and a body movement determination stage 41 on, like this in 3 is shown.

In this second embodiment of the influencing device 20 the comfort is taking into account the travel limits of the spring or damper units 11 optimized. The influencing device 20 knows the prepared lane profile h _L up to a point of maximum sensor range s _{max in} front of the vehicle. The actual levels y of the spring or damper units 11 be set in this section of the path s, in which the prepared lane profile h _{L is} known, that the maximum available available spring travel .DELTA.z _{max is} maintained and the build position z while driving the vehicle along the predetermined prepared lane profile along a Position trajectory moved with the least possible curvature. In this way, the comfort potential is optimally exhausted. The contour determination unit 40 For this purpose, a contour profile h _{K is determined} , which describes the position trajectory from several construction positions for the travel of the vehicle along the predetermined prepared roadway profile h _L , wherein the curvature of the contour profile h _{K is} minimized under the boundary condition that on the spring or damper units 11 maximum available spring travel Az _max are respected.

Consequently, in the contour determination unit 40 depending on the prepared lane profile h _{L determines} a contour profile h _K , which characterizes this position track. For example, the contour profile h _{K is determined} in the contour determination unit 40 by a particularly phase-free low-pass filtering of the prepared roadway profile h _L. The cutoff frequency of this low-pass filtering is chosen to be as low as possible, under the condition that in doing so the maximum available spring travel Δz _max at each spring or damper unit 11 is complied with. It should be noted at this point that the maximum available travel .DELTA.z _max depending on the actual levels of the individual spring or damper units 11 in the direction of the deflection and in the direction of the rebound of the respective spring or damper unit 11 is different in size and the values also change. At each spring or steamer unit 11 Therefore, a maximum compression travel .DELTA.z _{max, one} and a maximum Ausfederweg .DELTA.z _max, must be taken into account, which are summarized below .DELTA.z _{max for the} sake of clarity. The calculation method is basically the same for both values.

In the preferred embodiment, the lowest possible cut-off frequency for the low-pass filtering in the contour determination unit 40 determined iteratively. Starting from a starting frequency, the z. B. 0 Hz, a low-pass filter result TP is calculated and then checked whether the boundary condition of the maximum available spring travel can be met: | TP - h L | <Δz Max (Gl.9)

If the condition according to equation (Gl.9) is satisfied, the contour profile corresponding to h _K the low pass filter result TP. If this condition is not fulfilled and the maximum available spring travel Δz _{max is} reached or exceeded, then the starting frequency is increased and a new low-pass filter result TP is calculated. This iteration loop is run through until a low-pass filter result TP has been found which satisfies the boundary condition given in Equation (Eq.9). The contour profile h _K determined in this way is then sent to the body movement determination stage 41 transmitted.

The construction movement determination stage 41 calculated from the contour profile h _K is a contour body position z _K and a contour force F _K:

The contour force F _K becomes the Radbewegungsermittlungsstufe 23 supplied, which determines the calculated wheel position r _L in this second embodiment, based on the equation: m R · R .. L = c R (H L - r L ) - F k k R (H L - ṙ L ), (Gl.12) and m _{A is} the mass of the vehicle body 12 and ḧ _{L is} the time derivative of the prepared lane profile change ḣ _L.

The pilot unit 24 the calculated wheel position r _L and the contour buildup position are supplied. In this second embodiment of the influencing device 20 determines the pilot unit 24 in addition to the pilot control levels y _P for each spring or damper units 11 a pre-control build-up position z _P as a further pilot control variable, the to the body control 26 is forwarded. The pilot control quantities are as follows:

For the calculation of the skyhook level y _sk , corrected state values Δz, Δż are used for the compatibility of the precontrol by the pilot control unit 24 and the body structure 26 to improve. This will ensure that the body builder 26 and, for example, the skyhook controller 27 the pre-control levels y _P added to the skyhook levels y _{sk are} not regarded as disturbances and are at least partially compensated for again. The corrected state values are as follows: Δz = z - z P (Gl.15) Δż = ż - ż P (Gl.16)

The calculation of the corrected state values Δz, Δż takes place in a differential stage 42 ,

The in the skyhook controller 27 determined precontrol position z _P therefore results in:

For the skyhook restoring force F _e , the equations (Eq. 6) and (Eq. 7) apply as in the first exemplary embodiment.

Finally, as in the first embodiment of the influencing device 20 the target levels y _{should be} the individual spring units 11 calculated by equation (Eq. 8): y should = y sk + y PL (Equation 8)

Further improvement integrated feedforward control and bodywork regulation can be achieved when the skyhook controller 27 determines a skyhook correction term y _skk , which is added to the skyhook level y _sk and the filtered pilot level y _PL :

Instead of equation (Eq. y should = y sk + y PL + y skk (Equation 8)

4 shows a further, third embodiment of the influencing device 20 , Instead of the pilot dynamic filter 25 is a system dynamics level 45 provided in the determination of a to the bodywork regulation 26 passed on the dynamically optimized pilot control levels y _Pi on the basis of the pilot level y _P system behavior of the active suspension system taken into account, in particular its time or dynamic behavior when setting the pilot control variables. Otherwise, this third embodiment of the second embodiment of the influencing device 20 , Instead of the filtered pilot level y _{PL of} the second embodiment is now from the pilot level y _{P of} the pilot unit 24 the dynamics-optimized pilot control level y _Pi determines:

The coefficients u _i and w _i can be determined by the transmission behavior of the active chassis system of the vehicle used and thus differ in different vehicle types. This transmission behavior can be determined by measurements.

D_V

Ventildämpfung eines Steuerventils der Federeinheit 11;

ω_V

Ventilgrenzfrequenz

D_F

Positionsregelungsdämpfung

ω_F

Positionsregelungsgrenzfrequenz

q_Z

Konstante der Federeinheit 11, die den Einfluss des Drucks beschreibt

For example, the transmission behavior between the desired level y _soll and the actual level y of a spring or damper unit 11 an active suspension system with ABC spring or damper units 11b - see. 6b - be given as follows: y ... + 2D v ω v ÿ + ω v (2D F ω F q z + ω v (1 - q z )) ẏ + ω v ω 2 F q z y = q z ω v ω 2 F y should + q z ω v (2D F ω F - ω V ) y should (Gl.20) With:

D _V

Valve damping of a control valve of the spring unit 11 ;

ω _V

Valve cut-off frequency

D _F

Position Control damping

ω _F

Position control cut-off frequency

q _z

Constant of the spring unit 11 that describes the influence of pressure

From this differential equation, the transfer function G of the active suspension system can be determined with y = G · y should (Gl.21)

If the inverse transfer function G _{inv is} calculated therefrom, the relationship between the pilot control level y _p and the dynamics-optimized pilot control level y _{pi is obtained} : y pi = G inv * y P (Gl.22)

This results in the coefficients u _i and w _i in the approach according to equation (equation 19), which can then be used as a computational conversion of the inverse transfer function G _inv .

This procedure is analogous to the determination of the filter coefficients of the pilot dynamic filter 25 in the first two embodiments of the influencing device 20 ,

F_CD:

Federkraft

x:

Differenz zwischen Radposition und Aufbauposition

C_F:

Federkonstante der Feder

k_F:

Dämpfungskonstante des Dämpfers

Δk:

einstellbare Dämpfungsvariable

The with the help of the pilot unit 24 achieved feedforward control can be used for all active chassis, with which a body control is feasible. The above has been the application especially in active undercarriages with steerable active stabilizer 66 described. But it is also possible to use the springs or dampers of an active suspension system to control the body position. For this purpose, the described embodiments of the influencing device 20 be modified. With the aid of the determined level sizes for the spring or damper units 11 For example, a variable damping effect can be determined by the knowledge of the lane profile lying ahead of the vehicle via the pilot control unit 24 is changed. This can be done as follows:
The starting point is the following equation for a spring or damper unit 11 with adjustable damper: F CD = c F · X + (k F + Δk) ẋ (Eq.23) With:

F _CD:

spring force

x:

Difference between wheel position and body position

C _F :

Spring constant of the spring

k _F :

Damping constant of the damper

.delta..sub.k:

adjustable damping variable

For a spring or damper unit 11 with a variable level of the spring: F CD = c F (x + y) + k F (ẋ + ẏ) (Eq.24)

From the equations (Eq.23), (Eq.24) and (Eq.1) one obtains the adjustable damping variable:

On the basis of the equation (Eq. 25), the actual level y, the desired level y _soll , the pilot level y _p , the filtered pilot level y _PL and the dynamics-optimized pilot level y _{pi can be converted} into a respectively corresponding value for the damping variable. For example, the pilot unit 24 a pilot loss Δk _P and the skyhook controller 27 determine a skyhook attenuation Δk _sk , from which then a damping setpoint Δk _soll can _be determined. For the third embodiment of the influencing device 20 for example:

The dynamics-optimized pilot control damping Δk _Pi results analogously to the filtering of the pilot control level from the pilot control damping Δk _P as described above. Finally, the target damping can be determined .delta..sub.k P = Δk pi + Δk sk (Gl.28)

In this way, the feedforward control can be integrated into the body control if a spring or damper unit 11 with adjustable damper is used. This also applies accordingly to all other described embodiments of the influencing device 20 ,

By anticipating the roadway profile h in front of the vehicle in the direction of travel, the roadway excitations are also known, which at a certain point in time affect the vehicle wheels 10 act. Therefore, it is possible to predict the vehicle behavior at any time by a model and to compare it with the actual vehicle behavior. In this way deviations and / or errors can be detected. The precontrol can be corrected when deviations are detected, for example, the pilot control quantities y _P , z _{P of} the pilot control unit 24 be adapted to the current temperature or the state of wear of the vehicle.

For this purpose, the influencing device 20 a diagnostic unit 50 on. The diagnostic unit 50 For example, the prepared roadway profile h _L and / or the contour profile h _{K are} supplied to measured vehicle behavior describing the behavior or state of the vehicle and to one or more variables describing the roadway profile h (s).

The variables h _L , h _K describing the roadway profile h (s) are determined in a first diagnostic stage 51 Model values M are determined on the basis of a vehicle model, in particular the following model values: the expected wheel position r _M and / or the expected wheel vertical speed ṙ _M and / or the expected body position z _M and / or the expected body vertical velocity ż _M.

These model parameters M are sent to a second diagnostic stage 52 transmitted. In this second diagnostic step 52 also the measured current chassis sizes go, z. B. the wheel position r and / or the Radvertikalgeschwindigkeit ṙ and / or the body position z and / or the body vertical velocity ż.

The second diagnostic step 52 compares the model parameters with the measured chassis sizes and determines a deviation A that corresponds to a third diagnostic step 53 is forwarded.

The third diagnostic step 53 generates on the basis of the detected deviation A one or more correction signals, which serve the pilot control quantities y _p , z _{p of} the pilot control unit 24 to correct. In the embodiment of the diagnostic unit described here 50 At least one and, for example, a first correction factor P _y and a second correction factor P _{z are} determined, which serve to increase or decrease the pilot control quantities y _p , z _p , depending on the magnitude and sign of the deviation A. In the present case, the following applies: y P Corrects = P y * y P (Gl.29) z P Corrects = P z * z P (Gl.30)

The diagnostic unit 50 can in all three embodiments of the influencing device 20 after the 2 to 4 be used. In this case, instead of the pilot control variables y _p , z _p , the corrected pilot control variables y _{P, Corrected} and z _{P, Corrected} are used for the control.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - US 6233510 B1 [0002]

Claims (18)

Influencing device for influencing an active suspension system with at least one controllable Fahrwerkaktuator ( 60 ) of a vehicle, with a roadway sensor ( 21 ), which generates sensor data (d) from a lane in front of the vehicle in the direction of travel, which are used to determine a lane profile (h _L ), wherein a pilot unit ( 24 ) depending on the determined roadway profile (h _L ) determines a pilot control variable (y _P , z _P ), which serves the setting of the Fahrwerkaktuators ( 11 ) to the determined roadway profile (h _L ), characterized in that on the basis of the pilot control variable (y _P , z _P ) an input signal for a body structure ( 26 ), which serves to regulate the build-up position (z) of the vehicle body of the vehicle, and that as a Fahrwerksaktuator an actuator ( 60 ) a roll stabilization device ( 65 ), in particular an active stabilizer ( 66 ) serves. Influencing device according to claim 1, characterized in that the pilot control unit ( 24 ) determines a plurality of separate pilot control variables (y _P , z _P ), in particular a pilot control level (y _P ) for the actuator ( 60 ) of the stabilizer, which is used to determine a target level (y _soll ) on the connected to the stabilizer spring or damper units ( 11 ) and a pre-control assembly position (z _P ), which is used to influence a build-up position controller ( 27 ) of the body structure ( 26 ) serves. Influencing device according to claim 2, characterized in that at least the pre-control level (y _P ) in a modification stage ( 25 ; 45 ) taking into account given properties of the body structure ( 26 ) to a modified pre-control level (y _PL , y _Pi ) and to determine the target level (y _soll ) at the spring or damper units ( 11 ) serves. Influencing device according to claim 3, characterized in that the modification stage as system dynamics stage ( 45 ) is executed and from the pilot control level (y _P ) determines a dynamics-optimized pilot control level (y _Pi ), wherein the dynamic optimized pilot control level (y _Pi ) takes into account the dynamic behavior of the active chassis system of the vehicle. Influencing device according to one of claims 2 to 4, characterized in that the desired level (y _soll ) for a spring or damper unit ( 11 ) on the basis of the pilot control level (y _P ) and / or a modified pilot control level (y _PL , y _Pi ) formed therefrom and an output variable (y _sk ) of the build-up position controller ( 27 ) is determined. Influencing device according to one of claims 2 to 5, characterized in that the pre-control assembly position (z _P ) for correcting a to the build-up position controller ( 27 ) returned actual state value (z, ż) of the vehicle is used. Influencing device according to claim 6, characterized in that the build-up position controller ( 27 ) Instead of the actual body position (z) a (by means of the pilot assembly position z _P) corrected assembly position (Az) and / or instead of the actual structure of vertical velocity (Z) A (by means of the time derivative of Z _p) (the pilot assembly position (e.g. _P) corrected construction vertical velocity Az ) is supplied. Influencing device according to one of claims 1 to 7, characterized in that from the determined roadway profile (h _L ) in a Radbewegungsermittlungsstufe ( 23 ) a calculated wheel position (r _L ) is determined, which the pilot unit ( 24 ) is transmitted as input. Influencing device according to claim 8, characterized in that when determining the calculated wheel position (r _L ), the dynamic properties of the vehicle wheel ( 10 ). Influencing device according to claim 8 or 9, characterized in that at least one of the pilot control quantities (y _P ) is determined as a function of the calculated wheel position (r _L ). Influencing device according to one of claims 1 to 10, characterized in that on the basis of a lane profile (h) descriptive size (h _L ) a contour profile (h _K ) is determined, the a position track of several construction positions for the drive of the vehicle along the lane profile ( h), wherein the curvature of the contour profile (h _K ) is minimized under the boundary condition that the maximum of the spring units available spring travel can be maintained. Influencing device according to one of claims 1 to 11, characterized in that the up building regulation ( 26 ) is influenced by the pilot control variable (y _P , z _P ) or modified pilot control variable (y _PL , y _Pi ) in such a way that the buildup position (z) of the vehicle body ( 12 ) substantially follows the roadway profile in roadway excitations in a lower frequency range below a lower limit frequency. Influencing device according to claim 12, characterized in that the lower limit frequency is variable and depends on a roadway profile (h) descriptive size, in particular of the determined prepared roadway profile (h _L ). Influencing device according to claim 12 or 13, characterized in that the lower limit frequency is variable and depends on the on the spring units ( 11 ) maximum available spring travel (Δz _max ) Influencing device according to one of claims 12 to 14, characterized in that the body structure ( 26 ) is influenced by the pilot control variable (y _P , z _P ) or modified pilot control variable (y _PL , y _Pi ) in such a way that the buildup position (z) of the vehicle body ( 12 ) is maintained substantially unchanged in roadway excitations with frequencies above the lower limit frequency. Influencing device according to one of claims 1 to 15, characterized in that a diagnostic unit ( 50 ) is provided, which on the basis of a the road profile (h) describing size (h _L , h _K ) and a current state of the vehicle describing size (r, ṙ, z, ż) a deviation (A) between the expected state (r _M , ṙ _M , z _M , ż _M ) of the vehicle and the actual, current state (r, ṙ, z, ż) of the vehicle determined. Influencing device according to claim 16, characterized in that the diagnostic unit ( 50 ) determines the expected state (r _M , ṙ _M , z _M , ż _M ) of the vehicle on the basis of the prepared roadway profile (h _L ). Influencing device according to claim 16 or 17, characterized in that the diagnostic unit based on the deviation (A) determines a correction value (P _y , P _z ), which serves to adapt the pilot control variable and / or the modified pilot control variable (y _pL , y _pi ) ,