DE19918525B4 - Device for estimating the center of gravity of vehicles - Google Patents

Abstract

A vehicle attitude control system (2) comprising a vehicle stability control system (3) for receiving data of the driving operations and data related to the behavior of a vehicle (1) detected by sensors (11) mounted on the vehicle (1); Behavior of the vehicle (1) by the vehicle stability control system (3) can be estimated, and means (4) for receiving the data of the driving operations, the data relating to the behavior of the vehicle (1) and the calculation result of the vehicle stability control system (3) and the automatic delivery modification data for the vehicle (1) to be on the safe sides, characterized in that the vehicle stability control system (3) comprises means for determining the center of gravity height hs of a vehicle (1) in real time during the travel of the vehicle (1) Center of gravity height hs as a parameter in the vehicle stability control system (3) dbar is for estimating calculating the behavior of the vehicle (1) by comparing the coefficients of terms corresponding to terms of a transfer function (Φ (s) / δ (s)) of a roll angle Φ to a control angle δ, which is determined by ...

Description

The The invention relates to a device for estimating the center of gravity of vehicles according to the preamble of claim 1.

A such device may be in a vehicle attitude control system for the safe automatic control of the position of a vehicle based on vehicle behavior, e.g. B. yawing and rolling during the Ride the vehicle, to be used. It can also work in a vehicle attitude control system for automatically detecting and calculating the possibility of vehicle spin during the Drive the vehicle for automatic brake pressure control all or some wheels under possible Lowering the vehicle skidding, and further in a vehicle attitude control system for automatic stabilization the vehicle position when the vehicle is against the will of the driver due to driving outside the characteristic the vehicle, for example, a pronounced steering operation during the Driving the vehicle behaves. Furthermore For example, the invention is useful for commercial vehicles such as buses and to prevent trucks from rolling over.

It An electronic brake control device and a vehicle stability control system (VSC = "Vehicle stability control system ") known, which comprises an anti-lock braking system (ABS), which the rotation speed over detected a wheel speed sensor and then intermittently controls the brake pressure, thereby preventing that will Wheel opposite the road surface slips, if the wheel at large Brake pressure comes to a standstill.

The ABS is widely used in passenger cars and allows a Taxes during of braking. It is known that a vehicle stability control system may comprise an anti-skid device. This serves to the Course of the driver based on a through the operation of the driver adjusted steering angle (steering wheel angle), the vehicle speed automatically reduce without the driver pressing a brake pedal occurs when the vehicle speed is too high for his course, and then to distribute the left and right brake pressure so that of the Course is not deviated.

Out JP 63-279976 A . JP 3-112755 A , etc., a vehicle stability control system (VSC) is known, which will be described in detail below.

During the Driving a vehicle, the steering operation causes a change the direction of the vehicle during of the driving process. When the tire of the inner wheel above the Grip limit with the road surface is located while the vehicle is turning due to the steering, the inner wheel tends to be raised, whereby the vehicle begins to spin. For example, the straight-ahead driving direction causes Driver a tilt of the vehicle to the right. On this occasion that drives Vehicle the curve in the normal case according to the control; but when the speed of the control compared to the driving speed the vehicle is too big, the vehicle is tilted to the right while the left wheel tends to being raised, which makes the vehicle move to the right moved in relation to the course of the driver. Such behavior results in a deviation from the lane and in extreme cases to overturn of the vehicle.

It has been a wheel brake pressure control device for controlling the Brake pressure of the wheels before the start of skidding and lifting of the wheels Detection of steering angle and speed, vehicle speed, Vehicle lateral movement speed, vehicle course rate of change (yaw rate: Acceleration of the vehicle in rotation about the vertical axis) and to the subsequent Calculation of an estimate the wheel spin beginning and Innenradabhebebeginns developed. This device practices not necessarily the same brake pressure on all wheels, but exercises one larger or smaller brake pressure on each of the wheels, so a spin to avoid the vehicle. Such devices are adequate not only in terms of construction and design but also in economic terms Efficiency and durability have been investigated and therefore have one Reached stage in which they are in products in the market for passenger cars introduced can be.

Such Known devices are based on calculating the yaw rate on data that is based on the current Driving operation including Control and braking and data based on the current vehicle behavior and then to automatically control the brake pressure of the vehicle if the calculated yaw rate is a pre-set one and reaches the stored value at which the vehicle is skidding could, applied. Yaw rate is calculated using transfer functions based on data representing the current driving and the current Affecting vehicle behavior.

These Computation by means of transfer functions in a known transfer function calculating device usually uses the fast Fourier calculation, which is based on the current driving and the current vehicle behavior frequency-related data and then approximately their responsibility calculated by using the Fourier function. The fast Fourier calculation has the advantage that a general analyzer by installation in a computer can be used, is easily available.

In This vehicle attitude control system is the position of the vehicle's center of gravity an important parameter. Size Commercial vehicles, typically large trucks, change the position of their center of gravity according to the state of charge. Buses, especially shuttle buses, change the Position of their center of gravity according to the number of passengers. The Height of Vehicle center of gravity is an important parameter in the control the vehicle's attitude to a rolling over to avoid the vehicle.

It gives a known method for static measurement of the height of the vehicle's center of gravity, but no method for its dynamic measurement during the Ride the vehicle in real time. The static measuring method is to measure the position of the center of gravity on the respective wheels distributed loads during parking the vehicle on a horizontal road surface and subsequently the on the respective wheels distributed loads during of parking, when the vehicle is parked in relation to the Front and back direction inclined road surface and a respect the side direction inclined road surface has been moved, whereby the center of gravity position including the height of the center of gravity of the vehicle is calculated three-dimensionally.

Out DE 197 51 935 A1 A method is known for determining a size describing the center of gravity of a vehicle, which is preferably used to stabilize the vehicle in order to prevent it from tilting. In the method, various parameters such as drive / brake slip, wheel speed, yaw rate, lateral acceleration, vehicle speed and axle-related load are first read to determine the center of gravity height. If the drive / brake slip is below a preset threshold value, the wheel behavior can be calculated from the vehicle speed, the wheel speed and the yaw rate. From the wheel behavior, the behavior of the respective wheel axle and therefrom the center of gravity height of the vehicle is determined.

The known vehicle attitude control system will be described below with reference to FIG 21 to 23 described. 21 shows a general arrangement of a known vehicle attitude control system 2 , A vehicle 1 Adjust by the vehicle attitude control system 2 to be controlled object in the vehicle 1 Data is entered from driving operations such as steering, braking, acceleration and the like. The answer of the vehicle 1 consists in the behavior of the vehicle 1 , On the vehicle 1 is the vehicle attitude control system 2 assembled. The vehicle attitude control system 2 includes a Vehicle Stability Control System (VSC) 3 and an electronic brake control device 4 , A typical electronic brake control device 4 is the well-known anti-lock braking system (ABS).

To monitor the behavior of the vehicle 1 give on the vehicle 1 mounted sensors 11 behavioral data. The behavior related data includes information about the speed, the lateral acceleration, the yaw rate, the roll rate, the wheel revolution speed, and the like.

The vehicle stability control system 3 receives the data of the driving operations and the data concerning the behavior, then calculates the behavior of the vehicle in an estimating manner 1 and transmits the results to the electronic brake control device 4 , The electronic brake control device 4 similarly receives not only the data of the driving operations and the behavior of the vehicle 1 but also the output of the vehicle stability control system (VSC) 3 and then automatically provides modification data to modify the data relating to driving operations and the disturbance input to the vehicle 1 on their safe sides.

22 shows a system block diagram of a known vehicle attitude control system. An electronic control device 51 has a computer circuit controlled by programs and on the vehicle 1 is mounted. The control device 51 includes a vehicle stability control system (VSC) which receives the data regarding the driving operations and behavior and then the behavior of the vehicle 1 calculating and outputs a control unit to the vehicle according to the calculated output of the vehicle stability control system 1 the modification data for modifying the data relating to the driving operation input to the vehicle 1 and the clutter to their safe sides issue.

On the vehicle 1 are a yaw rate sensor 52 , a lateral acceleration sensor 53 , a roll rate sensor 60 and a forward and reverse direction acceleration sensor 61 mounted, their outputs with the control device 51 are connected. At four wheels 54 are each wheel speed sensors 55 whose detection output terminals are also connected to the control device 51 are connected. At a brake booster actuator 56 is a brake pressure sensor 57 attached, whose output also with the control device 51 are connected. At a steering wheel 58 is a steering angle sensor 59 attached, whose output also with the control device 51 connected is. In a speed controller 62 for controlling the internal combustion engine is a speed sensor 63 for detecting the state of the speed controller 62 installed, its output also with the control device 51 connected is. 23 is a perspective view of an example in which the vehicle 1 equipped with the above sensors. 22 and 23 each show a two-axle vehicle 1 ; However, large vehicles often have three or four axles.

• (1) Signaldaten, die eine geringe Frequenz besitzen, sind während einer langen Zeit erforderlich.
• (2) Die Anzahl der Daten muß die n-te Potenz von 2 (8, 16, 32, 64....) betragen. Die geeignete Anzahl von Daten könnte eventuell nicht erhalten werden.
• (3) Für den Fall, daß die Rückkopplungssteuerung in einer geschlossenen Schleife durchgeführt wird, ist die Berechnung nicht zugänglich, etc.

The fast Fourier calculation used in the calculation of the known transfer functions has the following disadvantages:

• (1) Signal data having a low frequency is required for a long time.
• (2) The number of data must be the nth power of 2 (8, 16, 32, 64 ....). The appropriate number of dates might not be obtained.
• (3) In the case where the feedback control is performed in a closed loop, the calculation is not accessible, etc.

Although commercial vehicles such as trucks and buses generally provide behavioral data whose oscillation frequency is about 1/100 Hz, the fast Fourier computation for the transfer function requires data extending over a period of 200 seconds, at least twice that period as large as the period of the calculation is, so that a device performing the calculation in real time while driving the vehicle 1 is not achievable. This leads to a big problem in realizing a vehicle attitude control system in commercial vehicles.

In addition, change at big Vehicles corresponding to the physical characteristics of the vehicle the number and positions of passengers, d. H. in case of a Passenger cars, the weight of the passengers (eg 50 kg per person) is small across from the total weight of the vehicle (eg 2,000 kg), even if the Number of passengers varies, and the number of passengers is small. Furthermore The focus positions of passengers are low set so that the execution the calculation with fixed physical properties with variation the number of passengers, the calculation results of the vehicle attitude control system hardly influence. In case of big Vehicles, especially trucks, vary the total weight of the vehicle and the center of gravity position largely depends on whether no loading exists or if the loading is close to the loading limit, so that the change the physical characteristics of the vehicle greatly. consequently the current results can not be calculated using the calculation obtained by means of a fixed vehicle model.

In addition, will a truck is not necessarily loaded consistently, so the weight and the position of the load or the center of gravity position in such Opportunities may vary. In case of big buses the number of passengers varies from zero to about fifty people, wherein the position of the passengers in the vehicle varies. The same applies to a shuttle bus every time he stops at a bus stop. consequently let yourself based on a fixed vehicle model no practical vehicle position control carry out.

What the center of gravity Under the above parameters, there is no procedure for Measuring the height the center of gravity of the vehicle in real time during the journey of the vehicle, although it is a static one described in the safety standard JIS There are procedures.

With In other words, the known measuring method is not able to the change to use the position of the vehicle center of gravity related data. In particular, for the case of a truck with varying loading weight and state of charge the position of the vehicle's center of gravity can not be measured when always the truck is loaded or unloaded; the vehicle position control is therefore based on estimates carried out.

In particular, the height of the vehicle's center of gravity varies according to the state of charge For example, the height of the center of gravity of the vehicle measured at the start of delivery of the vehicle varies when the vehicle is unloaded at the respective delivery location, so that it can not be used for the data of the vehicle attitude control system.

task The invention is an apparatus for estimating the center of gravity height of vehicles to provide according to the preamble of claim 1, by means of the Gravity height in real time during the ride of the vehicle measurable is.

These The object is achieved with the features of claims 1 or 2.

The Device is especially for size Vehicles, especially carrying loads Road vehicles, suitable. It is particularly in a vehicle attitude control system for big vehicles used in the related to the vehicle behavior data with not a few low frequency components.

A Such device has the advantage of being applicable to vehicles is whose charge or passenger state varies. It will be an adaptation reached to the loading or passenger state of the vehicle. Further This avoids large vehicles due to an over the characteristic of the vehicle running travel control of a Lane deviate and sideways tip over.

Further becomes the control accuracy of a vehicle attitude control system improved.

The Height of Vehicle center of gravity can be determined in real time. Here is the Height of Vehicle center of gravity based on a control angle input when the vehicle makes a left or right turn or changes its lane, and determined at this time roll angle.

Provided, that one Transfer function of a roll angle in a control angle in one dynamic model with a degree of freedom that has a roll angle contains and a transfer function of a roll angle in a steering angle, the current of the vehicle by means of an auto-regressive procedure (AR method) is, identical, it tries to find the coefficients of the terms corresponding degree, thereby reducing the height of the vehicle's center of gravity is derived.

Here, the AR method is a method of multiplying the data of the past by direction factors to make an inverse calculation to obtain the current data. Comparing the AR method with the fast Fourier computation (FFT) method, the FFT method has the advantage that a general analyzer is easy to obtain and the computation is completed in a short time, etc. One for components However, it is necessary to acquire the data for more than twice as long a period of time to obtain the appropriate resolution at low frequency (long period). For example, data related to the behavior of large vehicles includes frequency components of 1/100 Hz (long period), so that calculation in real time is not feasible. In contrast, in the AR method, the past data is multiplied by weighting factors to perform the inverse computation, thereby obtaining the corresponding results; the AR method is thus suitable for calculation in real-time control. In addition, the FFT method requires the number of data to be the nth power of 2, ie, 2 ⁿ , while the AR method, which has no data number limitation, allows calculation by data obtained at any time, thereby the degree of freedom is increased. Furthermore, by means of the FFT method, in principle no calculation can be carried out during a closed-loop control, ie a loop control in which the calculation for the return of the behavior related data without delay results, while the AR method is suitable for the closed loop calculation and Thus, it is advantageous for the device which constantly performs the loop control such as the vehicle position control.

• 1. Es ist hinreichend möglich, die Höhe des Fahrzeugschwerpunkts abzuschätzen.
• 2. Es ist möglich, die Differenz der Höhe des Fahrzeugschwerpunkts im Ladezustand, dem sogenannten gewöhnlichen Ladezustand, und dem Hoch-Ladezustand zu bestimmen.

When perceiving the rolling motion of the vehicle relative to a steering angle, the height of the vehicle's center of gravity is estimated by comparing the transfer function of a moving vehicle model with that of the "AR method model" obtained by using the experimental data, which following results shows:

• 1. It is sufficiently possible to estimate the height of the vehicle's center of gravity.
• 2. It is possible to determine the difference of the height of the vehicle's center of gravity in the state of charge, the so-called ordinary state of charge, and the high state of charge.

By means of the device, the center of gravity height of a vehicle can be determined on the condition that that a transfer function of a roll angle to a control angle input by a driver while driving the vehicle in a dynamic model having a degree of freedom that includes a roll angle and a transfer function of a roll angle to a control angle by means of an auto-regressive method (AR method), which are identical in coefficients of terms of corresponding degree.

Preferably comprises the device further comprises a vehicle response calculation circuit for the automatic renewal of the roll angle-in-steering angle transfer function by means of the auto regressive method (AR method) in real time during the Ride the vehicle, which is a device for displaying the roll angle-in-control angle transfer function (Φ (s) / δ (s)) as a quadratic equation with respect to of a differential operator s based on a value hs · f (s) according to an equation of motion of the vehicle with a center of gravity height hs, wherein the control angle input by the driver while driving the vehicle as function δ (s) in terms of a differential operator s and that due to the control angle roll angle induced on the vehicle by a function φ (s) in terms of a differential operator s are shown, and for illustration the roll angle to control angle transfer function (Φ (s) / δ (s)), renewed by using the vehicle response calculation circuit has been given as a quadratic equation with respect to a differential operator s and to the subsequent estimate the center of gravity hs using an equation in which both quadratic equations in terms of of the differential operator s in terms of coefficients of terms Grades are identical

Preferably comprises the device further comprises means for preferred use the center of gravity hs obtained by using an equation in which both quadratic equations re of the differential operator s in a coefficient of a term first Grades are identical, and the estimator includes a Device for zero correction of the control angle input and measured Roll rate using appropriate averages, a facility for setting times as start time and as end time when the measured Roll rate due to zero correction is zero while changing the measured roll rate is great and to the subsequent Querying the measured roll rate between the start time and the End time, and a bandpass filter means for passing the output data of the interrogator. this leads to to improve the estimation accuracy the height of the vehicle center of gravity.

Further Embodiments of the invention are the following description and the dependent claims refer to.

The Invention is described below with reference to the accompanying drawings illustrated embodiments explained in more detail.

1 shows a flowchart of a workflow according to a first embodiment.

2 shows a block diagram with a workflow according to the first embodiment.

3A and 3B each show diagrams representing the motion characteristic of a vehicle.

4A and 4B show diagrams that represent changes in a control angle or a roll rate.

5A and 5B show the applied dynamic model.

6 shows an illustration for the static measurement of the center of gravity height of a vehicle.

7 FIG. 12 shows a center of gravity estimated by sensing the roll angle of a vehicle during travel. FIG.

8A shows a graph with the relationship between a yaw rate and a steering angle and 8B shows a graph with the relationship between a roll angle and a control angle.

9 shows a flowchart with a working process according to a second embodiment.

10 shows a block diagram with a working process of the second embodiment.

11 shows a graph with a zero drift due to a fault of a meter.

12A and 12B show graphs with a zero setting using averages.

13A shows a graph with a known control scanning and 13B shows a graph with a known roll rate scanning zone.

14A shows a graph with a control scanning zone according to the second embodiment and 14B shows a graph with a known roll rate scanning zone.

15A to 15G show graphs with characteristics of a band-pass filter according to the second embodiment.

16 FIG. 12 is a graph showing an estimation result of the center of gravity height of the vehicle obtained according to the first embodiment. FIG.

17 FIG. 12 is a graph showing an estimation result of the center of gravity height of the vehicle obtained by the second embodiment. FIG.

18A to 18C show graphs with analysis examples of a general road.

19 FIG. 12 is a graph showing a result of the center of gravity height of the vehicle estimated on a test course and a general road. FIG.

20 shows a graph with estimated results of the center of gravity height of the vehicle in the unloaded, usually loaded and heavily loaded state.

21 shows a general arrangement of a known vehicle positioning system.

22 shows a block diagram of the known vehicle attitude control system.

23 shows a perspective view of a sensored vehicle.

Large vehicles are classified into two-axle, three-axle and four-axle types with one or more axle spacings. The movement characteristics are therefore different depending on the type of vehicles. 3A and 3B show graphs with a motion characteristic of a vehicle in which the abscissa axes in frequencies and the ordinate axes in gains in 3A or in phases in 3B are divided. The vehicles of the same axis type are stable regardless of the difference of the inter-axle distance WB (1) <WB (2) <WB (3), and the shorter the inter-axle distance, the larger the control sensitivity.

It also changes From the point of view of the use of the vehicle, the axle load considerably according to the state of charge, for example, no load, and changes accordingly the center of gravity of the vehicle considerably, which is why the position and height of the center of gravity as a movement characteristic of the vehicle is.

4A and 4B show graphs with the change of a control angle or the roll rate, in which the abscissa axes in time units and the ordinate axes in control angle units in 4A or in roll rate units in 4B are divided. These graphs show how the roll angle changes according to the center of gravity of the vehicle during a course change (required distance 40 m, speed 90 km / h). When the center of gravity height of the vehicle is large, the roll rate with a phase lag is large. Usually, the driver notices a state of vehicle rolling that changes according to the state of charge, thereby providing safety during the running of the vehicle.

5A and 5B show views of a dynamic model of a vehicle. Provided that a transfer function of a roll angle is input to a control angle input by a driver while driving the vehicle in a dynamic model having a degree of freedom including a roll angle and a transfer function of a roll angle to a control angle using of the auto-regressive method (AR method) are identical in terms of terms of terms of equal degrees, a comparison of these coefficients leads to a derivation of the height of the vehicle's center of gravity.

wobei hs der Abstand zwischen Schwerpunkt über Federung und Rollzentrum
hrs der Abstand zwischen Rollzentrum und Straßenoberfläche
I das Giermoment
Kf die Neigungskraft des Vorderreifens
Kr die Neigungskraft des Hinterreifens
Ms das Gewicht über Federung
M das gesamte Fahrzeuggewicht
Mu das Gewicht unter Federung
Kϕ die Rollfestigkeit oder -stabilität
Lf der Abstand zwischen Vorderachse und Schwerpunkt über Federung
Lr der Abstand zwischen Hinterachse und Schwerpunkt über Federung
V die Fahrzeuggeschwindigkeit
β der Seitenschleuderwinkel
γ die Gierrate
δ der Steuerwinkel
ϕ der Rollwinkel ist.According to the first embodiment, the creation of a dynamic model of a vehicle according to FIG 5A and 5B and then describing the movement of the vehicle to derive the roll angle to control angle transfer function according to a predetermined coordinate system. For describing the relationship between the center of gravity height of the vehicle and the roll angle, three degrees of freedom including the spin angle, the yaw rate and the roll angle are considered. The equation of motion is represented as follows:

where hs is the distance between center of gravity over suspension and roll center
hrs the distance between roll center and road surface
I the yaw moment
Kf the inclination force of the front tire
Kr the inclination force of the rear tire
Ms the weight over suspension
M is the total vehicle weight
Mu the weight under suspension
Kφ the roll strength or stability
Lf the distance between the front axle and the center of gravity via suspension
Lr the distance between rear axle and center of gravity via suspension
V is the vehicle speed
β the side spin angle
γ the yaw rate
δ the steering angle
φ is the roll angle.

As for the roll angle, the resolution of the above equation provides the following expression: φ (s) δ (s) = Cx = CA -1 B (1) in which
A = sE - A ',
E: unit matrix
det (A): determinant of A

Expression (1) is rewritten as follows:

An AR model obtained by subjecting the vehicle's current input and output data to an AR method is usually represented as follows: a (q) y (t) = b (q) u (r -nk) + e (t) (3)

Conversion of the above expression to the continuous system results in the maintenance of a transfer function, and hence the transfer function obtained is equal in degree to the theoretical expression (2), provided that the vehicle is currently moving at the degree of freedom described by the above theoretical expression. Assuming that the transfer functions of expressions (2) and (3) are identical in coefficients of terms of equal degree, the following is true. The center of gravity height (hs) of the vehicle is represented by the function with respect to a coefficient e _{2 of} the s ² term and vehicle related parameters. The determination of the coefficient e _{2 of} the s ² term and the parameter related to the vehicle makes it possible to derive the center of gravity of the vehicle, so that according to 5A and 5B the following expression is obtained:

6 shows a static method for measuring the center of gravity height of a vehicle. The method for static measurement of the center of gravity height of the vehicle includes a method described in the safety standard JIS, etc. In this embodiment, center of gravity heights of a medium sized truck are currently measured as true values in three equilibrium states loading concrete onto a truck load platform, a high state loading concrete thereon with elevation with a special rack, and a non-loading condition. The center of gravity hs of the vehicle is thus calculated using the following expression: hs = (W · Lr - Wf · L) / Wtanα where W is the total vehicle weight
Wf the weight added to the front wheel
L is the distance between the front and rear wheels
Lr is the distance between the center of gravity and the rear wheel
α is the angle of inclination.

When next be z. As the steering angle, the roll rate and the vehicle speed as behavior of the vehicle during measured the ride while the truck on a normal road driving in the usual traffic flow.

In 7 the state of the center of gravity of the vehicle is shown, which was estimated by querying the roll angle during the drive of the vehicle, wherein the abscissa axis is divided into time units and the ordinate axis in focal heights of the vehicle. The graph shows that the center of gravity of the vehicle is constantly fluctuating, and thus the direct and theoretical processing of the data obtained is problematic. 8A shows a graph with respect to the relationship of the yaw rate and the control angle and 8B shows a graph with respect to the roll angle and the control angle, wherein the abscissa axes in control angle and the ordinate axes in yaw rate units in 8A or in Rollwin in units 8B are divided. The above problem results from the fact that the roll rate is usually influenced compared to the yaw rate by bevels and irregularities of the road surface during the control, and thus a low correlation with the input control angle in FIG 8A and 8B has.

Under such circumstances, according to a second embodiment, for suitably detecting a component of the roll angle in response to the control angle, pre-processings in steps S1 and S4 according to FIG 9 continuously performed and input the preprocessed data into a device for estimation calculation of the center of gravity height of a vehicle.

11 shows a graph with a zero point migration due to an error of a measuring instrument, wherein the abscissa axis in units of time and the ordinate axis are divided into rolling rate units. A roll rate sensor 60 according to 22 and 23 has as a measuring instrument errors that lead to a zero point migration. The roll rate to be entered must therefore be unaffected by the zero point migration of the gauge.

12A and 12B show graphs with a zero point adjustment on the basis of the mean values, wherein the abscissa axes are in units of time and the ordinate axes are in roll rate units in 12A and the abscissa axes in roll rate units and the ordinate axes in frequency units in 12B are divided. In the second embodiment, according to 12A and 12B the mean value of accumulated measurement signals is set to zero.

Further will improve the correspondence between the steering angle and the roll rate triggered the queries by typing one Control angle a predetermined size and speed during a for the Steering angle possesses appropriate interval, reducing its coordination elevated becomes.

13A shows a graph with a known control polling zone and 13B shows a graph with a known Rollratenabfragezone, the abscissa axis in time units and the ordinate axis in control angle units in 13A or in roll rate units in 13B are divided. Traditionally, the polling interval is set as shown in the figures, thereby potentially erasing necessary data. In an in 13A and 13B example shown occurs according to 13A a portion of the control angle indicated by a circle slightly after the start of the control, while according to 13B the portion of the control angle designated by the circle is reflected to the roll rate after the completion of the polling. Thus, the roll rate corresponding to the portion of the control angle indicated by the circle becomes 13A corresponds, not entered, making a correct query impossible.

14A shows a graph with a control query zone of the second embodiment and 14B shows a graph with a known roll rate interrogation zone of the same, wherein the abscissa axes in time units and the ordinate axes in control angle units in 14A or in roll rate units in 14B are divided. To solve the in 13B Points in which the control angle and the roll rate are zero are considered to be the starting point and the end point, in this zone 500 and more data is exposed to queries.

15A to 15G FIG. 16 show graphs having characteristics of a band pass filter of the second embodiment. FIG. In 15A the abscissa axis is divided into time units and the ordinate axis is divided into roll rate units; in 15B the abscissa axis is divided into time units and the ordinate axis is divided into roll angle units; in 15C the abscissa axis is divided into time units and the ordinate axis is divided into control angle units; in 15D the abscissa axis is divided into time units and the ordinate axis is divided into roll angle units; in 15E the abscissa axis is divided into time units and the ordinate axis is divided into roll angle units; in 15F the abscissa axis is divided into time units and the ordinate axis is divided into roll angle units and the 15G For example, the abscissa axis is divided into frequencies and the ordinate axis is divided into power spectrum density units.

According to 15A . 15D . 15E and 15F For example, the roll rate is sensitive to lateral sway of the vehicle due to, for example, irregularities and oblique joints of the road surface in a high frequency range. On the other hand, according to 18A and 18B the fluctuation of the vehicle due to inclinations and grooves of the road surface to integration errors, when integrated in a low frequency range of the roll angle of the vehicle. To protect against such an influence, the use of a bandpass filter results in a low frequency which reduces the integration error and a high frequency containing disturbances due to road surface irregularities to be discarded, thereby improving sensitivity in the control sensing area.

After this processing has been performed, a transfer function is determined with an input and an output, whereby the center of gravity of the vehicle according to 9 can be derived in step S4. The second embodiment is characterized in that based on the coefficient e1 of the s-term, the center of gravity height of the vehicle is derivable, since the coefficient e1 is stable compared to the coefficient e2 in the first embodiment. When the coefficient of the s-term is denoted by e1, the center of gravity hs of the vehicle is represented by a function relating to the coefficient e1 and the vehicle-related parameters. In other words, the determination of the vehicle parameters and the coefficient e1 enables the transfer function according to FIG 9 the derivation of the center of gravity height as follows:

16 FIG. 12 is a graph showing the estimation result of the center of gravity height according to the first embodiment and FIG 17 FIG. 12 is a graph showing the estimation result of the center of gravity height according to the second embodiment. FIG. In 16 and 17 the abscissa axes are divided into time units and the ordinate axes are divided into centroid units. According to the first embodiment, the center of gravity height can be estimated in real time, though it is estimated only statically. According to 16 however, the estimate contains a large error compared to the true value. In the second embodiment shows 17 in that the implementation of steps S1 and S2 in 9 allows the estimated value and the true value to substantially coincide.

18A to 18C show graphs with analysis examples on a normal road. In 18A to 18C are the abscissa axes in time units and the ordinate axes in control angle units in 18A , in roll rate units in 18B and speed units in 18C divided. Furthermore, the examples are made 4A and 4B regarded as an example of the test course. 19 FIG. 12 is a graph showing the estimation result for the center of gravity height on a test course and a general road, wherein the abscissa axis for the case of a country road, e.g. B. a test course, and a general road a and b and the ordinate axis are divided into center of gravity.

In 15G For example, a control area designated by the arrow is used for determining the transfer function, and the correlation between the input control angle and the roll rate in this area is satisfactory, so that the estimation can be performed when the s / n ratio is large (section a in FIG 18A to 18C ). On the other hand, if the input and output are insufficient or the speed change is large (section b in FIG 21A to 21C ), an estimation result deviating from the true value is obtained. The estimation thus requires the assumption that the s / n ratio is large and the speed change is small.

In 20 an example is shown under the above assumption in which the centroid heights are calculated according to different states of charge. 20 FIG. 12 is a graph showing estimation results for the center of gravity height in an unloaded, a balanced loaded and a heavily loaded condition of the vehicle, wherein the abscissa axis is divided into centroid units corresponding to the states of charge and the ordinate axis. According to 20 the obtained center of gravity height varies according to the state of charge and the tendencies coincide. As a result, a vehicle attitude control system is provided which is suitable for large vehicles, in particular commercially usable vehicles. The vehicle attitude control system is applicable to large vehicles that include behaviorally related data with low frequency components to no small extent, as well as vehicles whose loading or passenger state changes, the vehicle following the change of the loading or passenger state. In a large vehicle, the deviation from a lane and a lateral overturning due to an over the vehicle characteristics carried out driving control is avoided. A center of gravity height is calculated in real time during the running of the vehicle and the control accuracy of the vehicle attitude control system is further improved.

Claims (5)

Vehicle attitude control system ( 2 ) comprising a vehicle stability control system ( 3 ) for receiving data of the driving operations and the behavior of a vehicle ( 1 ) by sensors ( 11 ) detected on the vehicle ( 1 ) are mounted, the behavior of the driving stuff ( 1 ) by the vehicle stability control system ( 3 ) is estimable, and means ( 4 ) for receiving the data of the driving operations, the behavior of the vehicle ( 1 ) and the calculation result of the vehicle stability control system ( 3 ) and automatically supplying modification data to allow the vehicle ( 1 ) is on the safe side, characterized in that the vehicle stability control system ( 3 ) Means for determining the center of gravity height hs of a vehicle ( 1 ) in real-time while driving the vehicle ( 1 ), where the center of gravity height hs is used as a parameter in the vehicle stability control system ( 3 ) is used for estimating the behavior of the vehicle ( 1 by comparing the coefficients of terms corresponding to terms of a transfer function (Φ (s) / δ (s)) of a roll angle Φ to a control angle δ, which is determined by a driver during the travel of the vehicle ( 1 ) in a dynamic model having a degree of freedom including a roll angle Φ and a transfer function of a roll angle Φ to a control angle δ obtainable by an auto-regressive method. Device for estimating the center of gravity hs of a vehicle ( 1 ) as a parameter for controlling the position of the vehicle ( 1 ), comprising means for determining the center of gravity hs of a vehicle ( 1 ) in real-time while driving the vehicle ( 1 ) as a parameter for estimating the behavior of the vehicle ( 1 by comparing the coefficients of terms corresponding to terms of a transfer function (Φ (s) / δ (s)) of a roll angle Φ to a control angle δ, which is determined by a driver during the travel of the vehicle ( 1 ) is input in a dynamic model having a degree of freedom including a roll angle Φ and a transfer function of a roll angle Φ to a control angle δ obtainable by an auto-regressive method. Apparatus according to claim 2, characterized in that further comprises a vehicle response calculation circuit for automatically renewing the roll angle in steering angle transfer function (Φ (s) / δ (s)) by means of the auto-regressive method in real time during the running of the vehicle ( 1 ) which includes means for representing the roll angle to steering angle transfer function (Φ (s) / δ (s)) as a quadratic equation with respect to a differential operator s based on a value hs · f (s) calculated according to a motion equation of Vehicle ( 1 ) with a center of gravity height hs, wherein the control angle input by the driver during the drive of the vehicle ( 1 ) as a function δ (s) with respect to a differential operator s and due to the control angle δ on the vehicle ( 1 ) are represented by a function Φ (s) with respect to a differential operator s, and representing the roll angle in steering angle transfer function (Φ (s) / δ (s)) renewed by using the vehicle response calculation circuit; as a quadratic equation with respect to a differential operator s and then estimating the centroid height hs by means of an equation in which both quadratic equations with respect to the differential operator s are identical in coefficients of terms of corresponding degree. Device according to claim 3, characterized in that in that a device for the preferred use of the center of gravity height hs, the is obtained by using an equation in which both quadratic Equations regarding of the differential operator s in a coefficient of a term first Grades are identical, is provided. Device according to one of claims 2 to 4, characterized in that a device for zero correction of the control angle input and measured roll rate using appropriate averages, a Device for setting times as start time and end time, when the measured roll rate due to the zero correction is zero while the change the measured roll rate is high, and to the subsequent Querying the measured roll rate between the start time and the End time, and a bandpass filter means for passing the output data provided by the interrogator.