JPH06278443A - Method and device for generating signal for effecting open or closed loop control of open or closed loop controllable chassis - Google Patents

Abstract

PURPOSE: To damp the then-existing movements of a vehicle individually as desired by driving the suspension system between a vehicle body and wheels based on a sensor technique detecting spring-displacement movements between a vehicle body and wheels, and detecting the vertical and horizontal movements of the vehicle body. CONSTITUTION: Respective sensors 1vl, 1vr, hl, hr sense the relative movements between the wheels of respective wheel units and a vehicle body, and this related matter, for example, a pressure difference in a damping system. Signals Zarvl, Zarvr, Zarhl, Zarhr are transmitted as the output signals to the first set 2 of filter units after being output and they are connected with one another. The outputs of the filter set 2 are complemented at additive connections 16, 17 of a unit 3 when the braking and the accelerating, and the steering operation are carried out. The outputs of a filter unit 3 are connected in the fourth unit one another, resulting in driving an actuator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for controlling a chassis, in particular an open-loop or closed-loop controllable motion sequence of a chassis of a passenger vehicle and / or a commercial vehicle having at least two wheel units. The present invention relates to a method and apparatus for generating a signal for closed loop control.

[0002]

BACKGROUND OF THE INVENTION Chassis design is of great importance in order to improve the driving comfort of passenger and / or commercial vehicles. There is a need for a spring and / or damping system that has good performance in this regard as a component of the chassis.

In the case of the passive chassis, which is mainly used in the past, the spring system and the damping system are
Depending on the expected intended use of each vehicle, it is set to hard mode (“sports type”) or soft mode (“comfort”) at the time of installation. In this system it is not possible to adjust the chassis characteristics during driving.

On the other hand, in the case of active chassis, the characteristics of the spring system and / or the damping system can be adjusted during driving by means of open-loop or closed-loop control, depending on the driving conditions, respectively. .

In order to open-loop or closed-loop control an active chassis of this kind, one must first consider a passenger / load-vehicle-road surface system. It is the vertical movement of the vehicle body that is felt by the occupant or the load that is vulnerable to impact as a loss of driving comfort. As a substantial cause of this movement of the car body, there is excitation due to unevenness of the road surface,
In addition, there are changes in driving conditions such as steering, braking and acceleration.

Therefore, comfort can be improved by reducing the body movement of the vehicle. Therefore, there are two possible approaches to act on and reduce body movement by means of active spring and / or damping systems.

First, in the first approach, the cause of body movement is detected. That is, the unevenness is detected before the vehicle reaches the unevenness of the road surface. Such a technique is described in, for example, DE-PS1158385. Furthermore, changes in driving conditions such as steering, braking and acceleration, which are other causes of body movement, can be detected by monitoring the corresponding actuators before they act on the vehicle body. For example, in order to detect a steering operation and / or an acceleration operation, a change in steering angle and / or throttle valve position can be detected. As a result, such an approach can effectively reduce body motion almost simultaneously with its occurrence.

Next, in the second approach, the body movement is determined and the body movement is canceled by the active chassis. In that case, the body movement can be determined directly by measurement, for example by using an acceleration sensor or indirectly by “reconstruction”, for example by measuring the amount of spring displacement and using a reconstruction method. it can.

In implementing the first approach, there are drawbacks with regard to the detection of road surface irregularities. This is because a sensor, for example an ultrasonic sensor or an optical sensor having a very complicated structure, is required for detecting the road surface unevenness.

A closed-loop control method for a chassis operating according to the second approach is, for example, DE-OS 3738.
No. 284. According to the method described in the publication, body movement is measured as vehicle acceleration. The drawback of this sensor system is that a relatively complex and expensive acceleration sensor is required.

EP-OS0321078 discloses a closed-loop control system for chassis.
In this system, the local acceleration of the vehicle body is determined without using the acceleration sensor. A spring system and / or a damping system are installed between the wheel unit and the vehicle body, and in particular, a spring system and / or a damping system acting on the vehicle body is obtained from a signal indicating a relative movement between the vehicle body and the wheel unit that ignores the damping force. The local vehicle speed at the point of action of the system is reconstructed. And this local body motion reduces the local body speed,
Used to open-loop or closed-loop control each local spring system and / or damping system.

The system described in EP-OS0321078 generally has three drawbacks. 1. Local body movements can be determined and reduced locally, but collective body movements such as pitching, rolling and bouncing are rarely considered. Therefore, it is not possible to adjust this collective body movement as desired and reduce it. 2. The method of reconstructing the body movement from the spring displacement movement can only obtain results which are applicable (for excitation by road surface irregularities) only in the case of straight running with a constant running speed. Therefore, a reduction in body movement is not guaranteed during steering, braking and / or acceleration operations. 3. In particular, it has been clarified that ignoring the damping force is not always optimum when reconstructing the local vehicle speed. This is because the damping force is generally not negligible compared to the spring force.

On the other hand, DE-OS 3408292 discloses a fully active spring system. In this system, the road surface of the vehicle body is determined based on the distance (spring displacement) between the vehicle body and the wheels. The averaged height position, the averaged pitching angle and the averaged rolling angle are calculated. Based on that, the operating force is determined, and based on that, the support unit arranged between the wheel and the vehicle body is driven, whereby the pre-calculated average height position or the calculated pitching and rolling angle is preset. It is adapted to the desired value in a possible way. In that case, the effects of unsteady running conditions (steering, braking, acceleration) are not taken into consideration. Therefore,
Since this system determines the averaged body movement and ignores the effects of unsteady running conditions, it is not possible to actually adjust the existing body movement to the desired level.

DE-OS 3408292 further describes body movements in the form of bouncing, rolling and pitching, which can be controlled independently of one another by closed-loop control. However, these ingredients are not the only possible choices. That is, the body motion is, for example: rolling and two vertical motions in the front and rear body regions; three vertical motions of the car body (not on one straight line); and three so-called modal motion components (this concept is The active chassis can be used to adjust the set of these motion components, and each component can be adjusted independently of each other.

German Patent Application No. P4039629.0-
No. 21, by dynamically filtering the measured spring displacement movements and taking into account the longitudinal and / or lateral movements of the vehicle, the existing body movements are reconstructed in the form of bouncing, pitching and rolling. To be done. Based on this, a so-called weighted vehicle speed at the working point of the suspension system of the vehicle body is determined by special weighting, and the vehicle body movement is damped by driving the suspension system as is known. In that case, the weighting is performed so that the modal motion components of the vehicle body are weighted with different strengths.

In German patent application P 41 1787.1, on the basis of a measurement signal representative of the local body movement of the vehicle at selected points of the body, the body movement present at that time is in the form of bouncing, rolling and pitching. Desired. Based on this value, the modal motion component of the vehicle body at that time is obtained and weighted with different strengths according to the running operation. Then, by driving the suspension system, a linear force is applied to the modal speed of the vehicle body.

[0017]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide a simple and inexpensive chassis capable of dampening a vehicle motion which actually exists at that time as desired and separately. It is to provide a control system.

[0018]

According to the invention, in order to achieve the object, an open-loop or closed-loop controllable motion sequence of a chassis of a passenger vehicle and / or a commercial vehicle having at least two wheel units is opened. Or a method for generating a signal for closed loop control, the first signal (Zarvl, Zarvr, Zarhl, Zarh) representing the relative movement between the wheel unit and the vehicle body.
r), and-a second signal (a) representing the longitudinal and / or lateral movement of the vehicle.
q, al) is detected, the first signal (Zarvl, Zarfr, Zarhl,
Zarhr) and the second signal (aq, al) are used to determine the actual modal velocity of the vehicle body in consideration of the characteristic values of the spring member and / or the damper member of the suspension system. By driving
A method for generating a signal for open-loop or closed-loop control of an open-loop or closed-loop controllable chassis is provided, which is characterized in that it produces a force which is a linear combination of the modal velocities of the vehicle body.

Further in accordance with the invention, there is provided a method for generating a signal for open-loop or closed-loop control of an open-loop or closed-loop controllable motion sequence of a chassis of a passenger vehicle and / or a commercial vehicle having at least two wheel units. An apparatus for implementing a first signal (Zarvl, Za) representing relative movement between a wheel unit and a vehicle body.
a first sensor (1ij) for detecting rvr, Zarhl, Zarhr) and means (6, 7) for detecting a second signal (aq, al) representative of longitudinal and / or lateral movement of the vehicle.
And the first signal (Zarvl, Zarvr, Zharh
1 and Zarhr) and the second signal (aq, al), the actual modal velocity of the vehicle body is determined in consideration of the characteristic values of the spring member and / or the damping member of the suspension system. Means (2, 3, 4, for producing a force that is a linear combination of the modal velocities of the vehicle body by driving the system
5) An apparatus for generating a signal for open-loop control or closed-loop control of an open-loop controllable or closed-loop controllable chassis is provided.

[0020]

According to the invention, a suspension system between the vehicle body and the wheels is based on a simple sensor technique for detecting the spring displacement movement between the vehicle body and the wheels and for detecting the longitudinal and / or lateral movement of the vehicle body. By driving, the forces can be exerted to isolate and dampen the natural vibration forms of the vehicle body. That is, the suspension system can exert a force proportional to the modal speed of the vehicle body.

Therefore, according to the invention of claim 1, the characteristic value of the spring member and / or the damping member of the suspension system is determined from the signal representing the spring displacement motion and the signal representing the longitudinal and / or lateral motion of the vehicle. In consideration of the above, the modal speed of the vehicle body existing at that time is obtained. Thereafter, driving the suspension system produces a force that is a linear combination of the modal velocities of the vehicle body. As a result, according to the present invention, it becomes possible to individually adjust and damp existing vehicle speeds.
The basis of the proportional damping of modal velocity by the skyhook closed loop control is the suspension
By driving the system, the forces are exerted so that the individual natural vibration forms of the vehicle body are isolated from each other and "skyhook damping".

In a preferred embodiment of the invention, the modal speed is adjusted additively and / or multiply according to a value representing the driving condition and / or a value for adjusting the driving condition.

Furthermore, it is preferable to detect the vehicle lateral movement by means of a steering angle sensor and / or by appropriately evaluating the signals of the wheel speed sensor. It is also preferable to use the signal of the wheel rotation speed sensor to detect the vertical movement of the vehicle. Furthermore, an appropriately positioned acceleration sensor can be used to detect the lateral or longitudinal movement of the vehicle.

The invention is preferably used especially for driving continuously adjustable semi-active suspension systems. Such continuously adjustable semi-active suspension systems are usually designed as spring and / or damping members, whose spring and / or damping characteristics are continuously adjustable.

The full-active suspension system makes it possible to apply forces independently of the spring displacement movement, which is not possible in the case of a continuously adjustable semi-active chassis control system. Instead of the target force, the hardest or softest adjustment is selected. For such a technique, for example, DE-OS35
It is described in Japanese Patent No. 24862.

A particularly preferred embodiment of the invention consists in adjusting the selectable rolling torque distribution of the vehicle.
Thereby it is possible to adjust the steering characteristics of the vehicle body, for example understeering, oversteering or neutral steering characteristics. Besides the method according to the invention, the invention also relates to a device for implementing the method according to the invention. Preferred embodiments of the invention are described in the dependent claims.

[0027]

An embodiment of the invention is shown in the drawing and will be explained in more detail below. In order to explain the concepts of natural vibration form, modal coordinates and principal vibration, the following will be explained first. As with each vibrating system, the vehicle also has (with respect to its vertical movement) a predetermined number of natural vibrational forms (modes) with a predetermined number of associated modal or principal coordinates. Each (vertical) movement of the vehicle is considered to be assembled from the natural vibrational form at each point in time. In that case, of course, over time, the proportion of the individual vibrational forms involved in the movement changes. The meaning of modal coordinates is to quantitatively describe the distribution of proportions or components. That is, at each point in time of movement, the value of each modal coordinate is equal to the rate at which the associated natural vibration form contributes to the movement.

The special (vertical) motion of the vehicle is the main vibration ("modal motion") of the vehicle. That is, it is characterized by being represented by only one natural vibration form during the whole movement. Thereby all modal coordinates always have the value zero, with one exception.

In vehicle technology, "bouncing (vertical movement about the center of gravity of the vehicle body)", "rolling (rotation about the vertical axis)" and "pitching" are used to describe the (vertical) movement of the vehicle body. (Rotation around the horizontal axis) "
Is often used. If these coordinates are also modal coordinates, for example, there is pure pitching in the sense that the center of gravity is stationary and no rolling takes place, ie there is a “pitching main vibration”. On the other hand, when only the rolling angle has a modal coordinate, the two bouncing and pitching motions of the main vibrations are combined. That is, vertical movement of the center of gravity and pitching are linked, and vice versa. In that case, in one of these main movements,
The bouncing component is dominant (bounce is “more”, pitching is “less”), while the pitching component is dominant.

Whether the bouncing, rolling and pitching angles of the vehicle body are in fact modal coordinates is largely related to two factors. One is the vehicle itself, and the other is how the chassis control system is configured (full active or semi-active). In general, rolling can be said to be modal coordinates if the chassis are arranged longitudinally symmetrically on the vehicle body and if the main inertial axes of the vehicle body coincide with its longitudinal, lateral and vertical axes. This vehicle characteristic applies to many of today's vehicles. Also, this vehicle characteristic applies regardless of the chassis control system used in each vehicle.

In a vehicle with a semi-active chassis control system realized, for example, by a traditional spring and chassis with controllable dampers, the bouncing and pitching angles are not always modal. That is, modal coordinates can be said to be the spring strengths c _V and c _H of the support springs for the front and rear axles.
And only when there is a predetermined relationship between the axial distances a and c with respect to the vehicle center of gravity (a * c _V = c * c _H ). Thus, when the ratio a * c _V / c * c _{H is} approximately 1, bouncing, rolling and pitching can actually be combined effectively (almost ideally) and adjusted.

What is important in use is that there is a special relationship between the mass moment of inertia I _{N with} respect to the horizontal axis of the vehicle body, the mass m _k, and the axial distances a and c (I _N = m _k * a * c). This is the case. This relationship applies, at least approximately, to many current vehicle types. In this case, the modal coordinates are given by the "forward" and "backward" vertical movements of the vehicle body (z _V and z _H ) as well as the rolling angle. Therefore, in this case, it is possible and important to adjust the "front" and "rear" movements and rolling of the vehicle body independently of each other by means of closed-loop control.

In the embodiment described below, the following steps are performed. 1. Based on the spring displacement motion signal, a dynamic filter is used to first determine the percentage of body motion present at that time. This percentage only reconstructs the actual body movement that is then present if the vehicle is not accelerated (longitudinal acceleration equal to zero) and runs straight (lateral acceleration equal to zero). (In that case, the excitation of the vehicle body movement is performed by the unevenness of the road surface).

2. The body movement rate determined in (1) is then corrected by considering the longitudinal and / or lateral movement of the vehicle accordingly. In some cases, the actual body movement can only be determined completely during all maneuvering operations by considering the longitudinal and / or lateral movements which are offset from zero. In that case, the description of the body movement is made in the coordinates of different combinations (three in each). For example: -Bouncing, rolling and pitching angles-Rolling angle and two points, eg vertical movement of the car body in the area in front of and behind the car body-Modal coordinates

3. Next, the description of the vehicle body motion in the modal component is performed (conversion from the instantaneous value of the selected coordinate to the instantaneous value of any modal coordinate). This relates to the mass distribution and suspension system and must therefore be determined separately for each vehicle beforehand. In particular, it is effective to immediately describe the body movement obtained at the point (1) and completed at the point (2) in modal coordinates. That is, in that case, step (3) is omitted.

4. Modal motion components are weighted independently of each other. This corresponds to the weighting of the natural vibration form. Because the instantaneous value of modal coordinates reconstructs the rate at which the associated natural vibrational form appears in the motion. That is, rolling of the vehicle body is more heavily weighted during curve travel (detected by lateral acceleration). During braking and / or acceleration maneuvers (detected by longitudinal acceleration), front and rear vertical body movements are more strongly weighted according to bouncing pitching or natural vibration forms, respectively.

5. The weighted instantaneous values of the modal motion components are converted to weighted bouncing, rolling and pitching. Ie (weighted)
Retransformed from modal coordinates to (weighted) bouncing, rolling and pitching coordinates. The "force distribution matrix" is then used to obtain the suspension system drive signals that represent the desired force. The selection of the elements of the force distribution matrix also makes it possible to select a selectable rolling or rocking torque distribution of the vehicle body.

Next, the system of the present invention for controlling the chassis in open loop or closed loop will be described with reference to the block circuit diagram. In this embodiment, the vehicle has four wheel units and two
Has a book axle. Further, in this embodiment, first,
Bouncing, pitching and rolling are assumed to be modal motion components of the vehicle body.

FIG. 1 shows a simple three-dimensional model of a vertically symmetrical four-wheel and two-axle vehicle. In the following, the index i indicates the relevant axle. That is, the index i = h indicates the characteristic belonging to the rear axle,
The index i = v describes the characteristics belonging to the front axle.
Reference numeral 30 indicates a spring system and a damping system. It should be noted that the spring and damping system 30 are each formed of a spring having a spring constant Ci and a damper arranged in parallel having a damping constant di. The wheel is designated 31 and is described by a body having a mass Mri and springs representing the wheel strength having a spring constant Cri, which are arranged one behind the other. Road surface is code 3
The vehicle body, which is shown at 3 and has a mass Mr, is shown at 32. The center of gravity S of the vehicle body is located at a distance a from the front axle and a distance c from the rear axle. "b" indicates a half wheel distance.

In the embodiment of FIG. 2, the main elements of the system are shown. Reference symbols 1vl, 1vr, 1hl, 1
Reference numeral 2 denotes a sensor, and a reference numeral 2 surrounded by a broken line is a first filter set including filter units 11, 12, and 13. A reference numeral 3 and a portion surrounded by a broken line are units for adjusting additively and / or multiplying, and reference numerals 16 and 17 indicate addition coupling, and reference numeral 1
Reference numerals 8, 19, and 20 denote multiplication combinations. Reference numerals 14 and 15 are filter units. The one surrounded by a broken line with reference numeral 4 is the second filter set of the filter units 21, 22, and 23, and the one surrounded with a broken line with reference numeral 5 is the suspension system 25vl or 2v of the controlled object.
5 vr, 25 hl, 25 hr. Reference numerals 6 and 7 represent means for detecting movements in the lateral and longitudinal directions of the vehicle.

Next, the active
The method of functioning of the system for generating the signals for open-loop or closed-loop control of the chassis will be explained with reference to FIGS. Each sensor 1vl, 1vr, 1hl and 1hr
For each wheel unit or spring system and / or damping system, the relative movement between the wheel and the vehicle body, eg relative spring displacement, and / or spring displacement rate, and / or its associated displacement, eg pressure difference in the damping system. To detect.

In this embodiment, a signal representing the relative spring displacement amount Zarij is output as the output signal. In that case, the index i indicates the corresponding axis. That is, the index i = h indicates the spring distance belonging to the rear axle, and the index i = v indicates the spring distance belonging to the front axle.
The index j indicates the side of the vehicle that belongs to the signal. That is, j = r indicates the right side of the vehicle, and j = 1 indicates the left side. In that case, left and right are selected with respect to the direction from the back to the front. These signals are obtained by direct measurement of the amount of spring displacement and / or by measuring the rate of spring displacement and / or the amount of displacement associated therewith, such as the pressure difference in the damping system. In the present embodiment, signals Zarvl and Zar are provided on the output side of the sensor 1ij.
vr, Zarhl, and Zarhr are output.

These signals are fed to the first set 2 of filter units, where they are combined with one another. This coupling is done in the filter units 11, 12, 13. Like all other filter units of the system, these filters are also electronically digital, for example by processing a differential equation representing a predetermined transfer characteristic in a calculation unit, or electronically analog, for example a predetermined transfer. It is realized by simulating a differential equation expressing the characteristic with an electronic device.

The entire first filter unit 2 is characterized by its transfer characteristic. The transfer characteristic is expressed by the following matrix description method,

[0045]

[Equation 1]

In that case, Sv (s) =-(Cv + dv * s) / (Mk * s), and Sh (s) =-(Ch + dh * s) / (Mr * s), and 1 / r = (b * Mk) / Iw, and l / p = (a * Mk) / In, and 1 / q = (c * Mk) / In, and s-Laplace variable a-previous Distance between axle and center of gravity of vehicle body c-Distance between rear axle and center of gravity of vehicle body b-Half wheel distance Mk-Mass of vehicle body Iw-Mass moment of inertia about vertical axis of vehicle body In-Mass moment of inertia about horizontal axis of vehicle body dv-damper constant of damper on front axle dh-damper constant of damper on rear axle Cv-strength of spring on front axle Ch-strength of spring on rear axle.

The above-mentioned vehicle-specific parameters, that is, the distance of the center of gravity and the mass moment of inertia must of course be known. Numerous methods have been shown in the prior art to obtain these data. These vehicle-specific parameters are further related to the loading status of the vehicle. That is, one or many parameters may change, especially when loaded on one side. Numerous approaches can be taken to address these issues.

The system according to the invention applies to empty vehicles or vehicles with a typical load distribution. In that case, if the actually existing parameters deviate from the applied parameters, the operation of the system of the present invention may be slightly changed, but the basic idea of the present invention is not lost.

The selection of various parameter sets can be considered according to the loading state. That is, the system of the present invention is always adapted to each condition.
Therefore, in the first filter set 2, the spring displacement signal is linearly combined as follows.

[0050]

[Equation 2]

Mutual coupling is achieved by the four-component vector (Zarv
l, Zarvr, Zarhl, Zarhr) can be mathematically given by matrix multiplication by the matrix (1) characterizing the transfer characteristic. The individual filter units 11, 12, 13 can for example be designed as adder units according to the vector-matrix multiplication rules as follows. Filter unit (FE) 11: Zarvl * Sv + Z
arvr * Sv + Zarhl * Sh + Zarhr * Sh FE12: Zarvl * Sv / r-Zarvr *
Sv / r + Zarhl * Sh / r-Zarhr * Sh /
rFE13: -Zarvl * Sv / p-Zarvr *
Sv / p + Zarhl * Sh / q + Zarhr * Sh /
q

The result of the combination based on the above equation corresponds to the bouncing, rolling and pitching speeds (zb ', alphab' and betab ') of the vehicle body in the case of straight running without acceleration (only in the case of excitation by road surface unevenness). In that case, alpha or beta indicates rotation about the vertical or horizontal axis of the vehicle body, and zb indicates bouncing of the vehicle body. alpha ', beta' and zb 'are first-order time derivatives of the variables alpha, beta and zb, respectively.

It should be additionally noted that the first filter set 2 is a filter having a dynamic transfer characteristic.
Only by taking into account the dynamic characteristics of the wheels and the car body is it possible to reconstruct the existing car body motion from the spring displacement motion.

The combined result (alphab 'and betab') at the output of the first filter set 2 is that the rolling and pitching speeds (alpha ', be) present at that time only if the vehicle is traveling straight without acceleration.
ta ') is reconstructed, in which case the bouncing velocity zb' is independent of the acceleration state of the vehicle,
That is, zb '= z'. When braking, acceleration and / or steering operations are performed, the rolling and pitching speeds ahpab 'and betab' are defined by the terms alphaq '= (Ew (s) * aq) / (Iw * s) and betal' = ( En (s) * al) / (In * s) (2) only due to the addition couplings 16 and 17 in unit 3 alpha '= alphab' + alphaq 'and beta' = betab '+ betal' and zb '= z' (3 ) Is supplemented. In that case, aq and al are the longitudinal and lateral accelerations of the vehicle detected by the means 6 and 7. Ew and En are transfer functions, in which case s represents a Laplace variable. The variables Ew and En can be calculated based on the tire model. In the simplest embodiment of the system of the invention, the variables Ew and En have the formulas Ew = h * Mk and En = -h * Mk (4), where Mk is the mass of the vehicle body and h is the vehicle mass. Indicates the height of the center of gravity of the.

The bouncing, pitching and rolling velocities (z ', beta' and alpha ') which are thus supplemented and which reproduce the existing body movements in the case of steering, braking and accelerating maneuvers are then multiplied by 18 , 19, 20 are weighted. This is done by multiplying by the variables gh, gw and gn,
It can be done separately from each other.

The values gh, gw and gn are preferably selected in accordance with variables and / or adjusting variables which describe the driving condition of the vehicle, such as the speed, braking, steering and / or acceleration and / or ambient temperature.

The output side of the third filter unit is therefore weighted bouncing, pitching and rolling speeds (zg ', betag' and alpha).
ag ') is output.

The lateral and / or longitudinal acceleration signals aq and / or al are applied to the inputs of the filter units 14 and 15, while the signals alphaq 'and betal' are output to the outputs of the filter units 14 and 15, The transfer characteristics of the unit are Ew (s) / (Iw * s) for the filter unit 14 and En (s) / (In for the filter unit 15 according to equation (2).
* S).

Signals representing the lateral acceleration aq and the vertical acceleration al of the vehicle are detected by means 6 and 7. This can be done, for example, by a suitable acceleration sensor.

Preferably, however, the lateral acceleration signal aq of the vehicle is derived from the signal of the steering angle sensor, especially if these signals are used for power steering open loop or closed loop control, for example.

Further preferably, the signal al of the longitudinal acceleration of the vehicle is required to be a signal of a wheel speed sensor used in, for example, an antilock braking system.

In summary, in order to adjust in the unit 3, first the actual pitching and rolling speeds are reconstructed from the relative distance signals between the vehicle body and the wheels and the signals representing the lateral acceleration aq and the longitudinal acceleration al of the vehicle. And on the other hand the body movement which is then present can be adjusted as desired, so that, for example, the predetermined movement is used in particular in the subsequent data processing and switching of damping characteristics,
Or it can be attenuated.

In the above-described embodiment, the vehicle body center of gravity is vertically moved (bouncing) as coordinates to describe the vehicle body movement, the vehicle body is rotated about the vertical axis (rolling angle), and the horizontal axis of the vehicle body is centered. The rotation (pitch angle) is required. In addition, bouncing, rolling and pitching form the movement components that are to be adjusted independently of each other by closed loop control. This is especially important only when the coordinate bounce, roll and pitch angles are modal. Therefore, individual adjustments of bouncing, rolling and pitching focus on modal motion components at their core.

As described above, bouncing, rolling and pitching have a predetermined relationship between the spring strengths c _V and c _H of the support springs of the front and rear axles and the distances a and c to the center of gravity of the vehicle. Only when (a * c
_V = c * c _H ), which is a modal motion component. Ratio a * c _V
Bouncing only if / c * c _{H is} approximately 1,
Rolling and pitching can actually be effectively (nearly ideally) decoupled and adjusted.

When the present invention is applied to a vehicle, there is a special relationship between the mass moment of inertia I _N with respect to the horizontal axis of the vehicle body and the mass m _k and the axial distances a and c (I _N
= M _k * a * c) This is the second case. As already mentioned, this relationship applies at least approximately to many current vehicle types. In that case, the modal coordinates are given by the vertical movements (z _V and z _H ) of the vehicle body "front" and "back" (as already explained), in addition to the rolling angle.
Therefore, it is possible and important here to adjust the movement and rolling of the vehicle "front" and "rear" independently of each other using closed-loop control. Of course, this requires a calculation and weighting method, which is a little different from the method shown in FIG. Next, this modified method will be briefly described. The variables used below are extracted from the list of matrix (1).

1. Determine the bouncing, rolling and pitching velocities (z ', alpha', beta ') from the measured spring displacement movements, longitudinal and lateral accelerations (as in the previously described embodiments).

2. Convert to modal velocity component: Calculate the vertical velocity of the vehicle body at the points in the front and rear vehicle body regions from the obtained bouncing and pitching velocities z'and beta 'according to the following equation. z _v '= z'-a * beta' z _h '= z' + c * beta '

3. Modal velocity components z _v ', z _h ', al
pha 'z _vg weight the (rolling speed) independently of one _{another' = gvo * z v 'z} hg' = ghi * z h 'alpha g' = gw * alpha ' weighting factors GVO, ghi and gw is preferably It is selected according to the variables that represent the driving conditions such as the running speed of the vehicle, braking, steering and acceleration operations, and / or ambient temperature, and / or variables that are adjusted.

4. Reconverted to bouncing, rolling and pitching velocities: weighted modal velocities z
_vg 'and z _hg' bouncing and pitching velocity z _g weighted from 'and beta _g' is calculated. z _g '= [c / (a + c)] * z _vg ' + [a / (a +
c)] * z _hg 'beta _g ' =-[1 / (a + c)] * z _vg '+ [1 /
(A + c)] * z _hg 'Steps 2-4 can be summarized as described below.

[0070]

[Equation 3]

In that case, g11 = [c / (a + c)] * gvo + [a / (a +
c)] * ghi g13 =-[(a * c) / (a + c)] * [gvo-g
hi] g22 = gw g31 =-[1 / (a + c)] * [gvo-ghi] g33 = [a / (a + c)] * gvo + [c / (a +
c)] * ghi

The system according to the invention in this embodiment therefore has the following characteristic that the body movements which can be adjusted independently of one another according to the geometrical distribution of the mass of the vehicle and / or according to the parameters characterizing the suspension system: Bouncing, pitching and rolling, and / or rolling and vertical movement of the vehicle body in the front and rear axles.

[0073] Thus according to a modal motion elements, bouncing, pitching and rolling speed (z ', beta', alpha ') or vertical speed of the vehicle body in the rolling rate and the front axle and rear axle (beta', z _v ', z _h ') is weighted.
Therefore, as is apparent from the above description, the modal speed of the vehicle body is weighted.

In both cases, in this embodiment the output side of the third filter unit is weighted bouncing, pitching and rolling speeds (z _g ', bet
a _g 'and alpha _g ') are output.

In the case of a four-wheel, two-axle vehicle in which an active or semi-active actuator is arranged between each wheel and the vehicle body, a weighted output to the output side of the third filter unit (3), Alternatively, the amplified bouncing, pitching and rolling velocities (z _g ', beta _g ', alpha _g ') are combined with each other in the fourth unit (4). The transfer characteristic of the fourth unit (4) has the following characteristics in the matrix description method.

[0076]

[Equation 4]

In this case, the elements of the "force distribution matrix (5)" are:-: F11 = F21 = a2 / (a1 + a2)-: F31 = F41 = a1 / (a1 + a2)-: F12 = -F22 = (1 / b1) * (ro / ro +
1) −: F32 = −F42 = (1 / b2) * (1 / ro +
1)-: F43 = F33 = -F23 = -F13 = 1 / (a
1 + a2), and-: a1 is the distance between the center of gravity of the vehicle body and the front axle,-: a2 is the distance between the center of gravity of the vehicle body and the rear axle, and-: 2 * b1 is the actuator at the front axle. Is the distance of the point of action on the vehicle body, and-: 2 * bw is the distance of the point of action of the actuator on the vehicle body at the rear axle. The meaning of the variable ro will be described later.

Thus, in the fourth unit (4), the weighted bouncing, pitching and rolling speeds (zg ', betag', alphag ') are linearly combined as described below.

[0079]

[Equation 5]

The mutual connection is defined by the three-element vector (z _g ',
It is mathematically obtained by matrix multiplication of alpha _g ', beta _g ') with the force distribution matrix (5) that characterizes the transfer characteristic. In this case, the individual filter units 21, 22, 23 and 24 can be designed as multiplication and addition units as follows, for example according to the vector matrix multiplication rules. Unit 21: (F11 * z _g ') + (F12 * alpha _g ')-(F13 * bet
a _g ') Unit 22: (F21 * z _g ')-(F22 * alpha _g ')-(F23 * bet
a _g ') Unit 23: (F31 * z _g ') + (F32 * alpha _g ') + (F33 * bet
a _g ') Unit 24: (F41 * z _g ')-(F42 * alpha _g ') + (F43 * bet
a _g ') The variable Fij is defined as described above.

At the output side of the fourth unit (4) as a result of the coupling, the coupling results (fvl, fvr,
fhl, fhr) is output. This control force is considered as the target force for the hydraulic cylinder (active system) or for the adjustable damper (semi-active).

Combined result (fvl, fvr, fhl, fh
The actuator is driven using r). By supplying drive signals (fvl, fvr, fhl, fhr) to the actuator, a control force corresponding to the target force is provided.

In a particularly preferred embodiment of the present invention,
Cascaded control circuits are used to drive the actuators. Drive signal (f
If vl, fvr, fhl, fhr) are linear control voltages, the non-linear control characteristics of the damper, in particular the semi-active damper, are taken into account so that a control force corresponding to the desired force is produced.

When the semi-active system is used, a signal representing the relative motion between the wheel unit and the vehicle body of the vehicle is detected, and the drive signals (fvl, fvr, fhl, fhl) are detected.
It is necessary to make a damper adjustment by comparing hr) with the spring displacement movement. Furthermore, if the control power is not realized, the hardest or softest adjustment can be selected instead. This is, for example, described in German Patent Application No. P 3930555.4, by means of an alternative hard or soft adjustment of the relative movement between the wheel unit and the vehicle body according to the desired force and its associated movement. Can be done by considering so that

To physically interpret the force distribution matrix (5), it can be assumed that the relationship (6) is approximately equal to fvl + fvr + fhl + fhr = z _g '(7a) b1 * (fvl-fvr) + b2 * (fhl-fhr) = alpha _g ' (7b) -al * (fvl + fvr) + a2 * (fhl + fhr) = beta _g (7c) b1 * (fvl-fvr)-ro * b2 (fhl-fhr) = 0 (7d)

To understand this, form a linear combination of the forces (fvl, fvr, fhl, fhr) described in (7), where the force itself is replaced by the right side of (6). All you have to do is

The relation (7a) can also be described as ro = [b1 * (fvr-fvl)] / [b2 * (fhr-fhl)] = konst | t (8), where two numerator are included in the numerator. The rolling torque of the front control force and the rolling torque of the two rear control forces are described in the denominator. The parameter ro thus describes the rolling or rocking torque distribution (front / back) of these forces, and equation (8) shows that the distribution is independent of time. Furthermore, its value in the force distribution matrix can be chosen freely.
Therefore, by selecting the parameter ro, an adjustable swing of the control force and / or a rolling torque distribution is obtained.

Regarding the physical meaning of the remaining relations in (7), the body motion equation Ma * z "=-(fvl + fvr + fhl + fhr) + F (9a) Iw * alpha" = -b1 * ( You can think of fvl-fvr)-b2 * (fhl-fhr) + Mw (9b) In * beta "= a1 * (fvl + fvr)-a2 * (fhl + fhr) + Mn (9c), in which case The "" after the variables means the second-order time derivative of each variable.
F is a force exerted by a force that is not a control force. This force is the force that the passive chassis element exerts on the vehicle body. Further, a disturbance force or the like is also considered within this force F. Mw
And Mn are the torques this force brings about the rolling (longitudinal) and pitching (horizontal) axes. Iw and I
n is the mass inertia torque centered on the relevant axis. The motion formula (9) is based on the model idea that the vehicle body forms a fixed main body, and is rotated from the equilibrium position alpha and b.
This holds when eta is small.

Control force (fvl, fvr, fhl, fh
If r) is determined by the force distribution matrix, ie according to equation (6), equation (9) shifts to the form for controlled movement. (Ma * z ") + (g11 * z ') + (g12 * beta') = F (10a) (Iw * alpha") + (g22 * alpha ') = Mw (10b) (In * beta ") + (g31 * z ') + (g33 * beta') = Mn (10c) This is done directly from Eqs. (7) and (4).

First, when considering the problem of adjusting bouncing, rolling and pitching independently of each other, the weighting factors g12 and g31 are preferably selected to be zero. In that case, the influence of the remaining tuning parameters g11, g22 and g33 can be clearly known. g22, for example, damps almost only rolling (coupling with bouncing or pitching occurs only when the moment M _w is related to these movements). Similar things g11 and g3
The same applies to the effect of item 3. That is, bouncing, rolling and pitching vibrations can be individually damped.

However, for example, when it is desired to adjust the vertical vibrations of the vehicle body on the front and rear axles of the vehicle body independently of each other and by weighting them with different intensities, g12 and g31 should generally be different from zero. It is necessary to select and properly tune all weighting factors sequentially.

When considering the above-mentioned proposal for improving the driving comfort in a wide range of chassis control concepts, as already explained, all the weighting factor values are set to the driving state variables, for example, the driving speed, the vertical direction and the lateral direction. It is important to choose according to the instantaneous value of acceleration. That is, for example, in the case of braking and acceleration, g11 and especially g33 can be selected to be large (compared to g22), and the bouncing / pitching vibration generated thereby can be quickly eliminated. On the other hand, when cutting a curve, g
Increasing the value of 22 (compared to g11 and g33) has a favorable effect. This is because then the excited rolling is reduced rapidly. In this way, it is possible to determine a predetermined number of parameter sets corresponding to a predetermined driving situation and operation (characterized by the value region of the driving state variable).

[0093]

As is apparent from the above description, according to the present invention, the actually existing pitching and rolling speeds are reconstructed from the relative distance signal between the vehicle body and the wheels and the signals representing the lateral acceleration and the longitudinal acceleration of the vehicle. It is possible to configure and adjust the existing body movements as desired.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a three-dimensional vehicle model to which the present invention can be applied.

FIG. 2 is a block diagram showing a main element of the present invention.

[Explanation of symbols]

 1vl, 1vr, 1hl, 1hr Sensor 2 First filter set 3 Additive and / or multiplicative adjustment unit 4 Second filter set 5 Suspension system 6, 7 Means for detecting lateral and longitudinal movements of a vehicle

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Andreas Krug, Germany, 7,000 Stuttgart 10, Foyerbacher Beek 15 (72) Inventor Peter Maisna, Germany, 7014 Kornbastheim, Georg-Friedrich-Hendel- S (No house number) (72) Inventor Stefan Otterbein Germany 7,000 Stuttgart 30, Heidestraße 45

Claims (9)

[Claims] 1. A method for generating a signal for open-loop or closed-loop control of an open-loop or closed-loop controllable movement sequence of a chassis of a passenger vehicle and / or a commercial vehicle having at least two wheel units, the method comprising: a wheel unit; A first signal (Zarvl, Zarvr, Zarhl, Zarh) representing the relative movement between the vehicle bodies.
r), and-a second signal (a) representing the longitudinal and / or lateral movement of the vehicle.
q, al) is detected, the first signal (Zarvl, Zarfr, Zarhl,
Zarhr) and the second signal (aq, al) are used to determine the actual modal velocity of the vehicle body in consideration of the characteristic values of the spring member and / or the damper member of the suspension system. By driving
A method of generating a signal for open-loop or closed-loop control of an open-loop or closed-loop controllable chassis, characterized in that it produces a force which is a linear combination of the modal velocities of the vehicle body. 2. Method according to claim 1, characterized in that the modal speed is adjusted additively and / or multiply according to a value representative of the driving state and / or a value for adjusting the driving state. . 3. A first signal (Zarvl, Zarvr, Zarvr, Zarvr, for determining the actually existing modal velocity of the vehicle body.
Method according to claim 1, characterized in that Zarhl, Zarhr) are dynamically filtered. 4. The actual modal velocity of the vehicle body, according to the geometric distribution of the mass of the vehicle, and / or
Alternatively, the vehicle body bouncing, pitching and rolling speed or rolling speed and the vertical speed of the vehicle body at the front and rear axles are determined according to the parameters that characterize the suspension system,
The method according to claim 1, 2 or 3. 5. The suspension system is formed from a spring member and / or a damper member whose spring and / or damping characteristics are continuously adjustable, as claimed in claim 1, 2, 3 or. 4. The method according to any one of 4 above. 6. A linear combination of different modal velocities of the vehicle body is selected to adjust the selectable rolling torque distribution of the vehicle.
The method according to any one of 3, 4, and 5. 7. In the case of a semi-active suspension system, the hardest adjustment or the softest adjustment is selected instead of the unrealized target force. 7. The method according to any one of 4, 5, and 6. 8. A signal from at least one steering angle sensor and / or a signal from a wheel speed sensor and / or a signal from an acceleration sensor is used to detect the second signal (aq, al). And claim 1, 2,
8. The method according to any of 3, 4, 5, 6 or 7. 9. An apparatus for implementing a method for generating a signal for open-loop or closed-loop control of an open-loop or closed-loop controllable movement sequence of a chassis of a passenger vehicle and / or a commercial vehicle having at least two wheel units. A first signal (Zarvl, Zarvr, Zarhl, Zarhr) representing the relative movement between the wheel unit and the vehicle body.
A first sensor (1ij) for detecting the vehicle and a second signal (a) representing the longitudinal and / or lateral movement of the vehicle.
means (6, 7) for detecting q, al) and a first signal (Zarvl, Zarvr, Zarhl, Z).
arhr) and the second signal (aq, al), the modal velocity actually present in the vehicle body is determined in consideration of the characteristic values of the spring member and / or the damping member of the suspension system, and the suspension system is further determined. An open-loop controllable or closed-loop controllable chassis, characterized in that it comprises means (2, 3, 4, 5) for driving to produce a force which is a linear combination of modal velocities of the vehicle body. A device that generates a signal for controlling open-loop or closed-loop.