DE102008027621A1 - Method for determining the roll angle of a single-track motor vehicle - Google Patents

Abstract

The invention relates to a method and a measuring arrangement for determining the roll angle (alpha) of a single-track motor vehicle (BIK). With two yaw rate sensors (D1, D2) around different axes (VA, LA) of the vehicle, two yaw rates (r1, r2) are determined, and from these yaw rates (r1, r2) are filtered roll angles (alpha1 <SUP> * </ SUP> , alpha2 <SUP> * </ SUP>), which are added to a resulting roll angle (alpha <SUP> * </ SUP>). According to the invention, to determine the second value (alpha2 <SUP> * </ SUP>) for the roll angle, the rotation rate (r2) determined by the longitudinal axis rotation rate sensor (D2) is low-pass filtered with the cutoff frequency (fg) and with a reciprocal of the cutoff frequency ( fg) proportional gain function amplified.

Description

The The invention relates to a method for determining the roll angle a single-track motor vehicle, wherein by means of at least two Yaw rate sensors at least two yaw rates of the vehicle to two different axes are determined, where a) by means of a first rotation rate sensor a rate of rotation about a vertical axis of the vehicle is determined, and b) by means of a second rotation rate sensor a Yaw rate is determined around the longitudinal axis of the vehicle, and wherein c1) from the determined rate of rotation about the vertical axis together with a speed signal for the speed of the vehicle a first value for the roll angle of the vehicle as a function the time is determined, wherein the first value for the roll angle is filtered at frequencies above a cutoff frequency, so that a low pass filtered value for the first roll angle gives, or c2) where the yaw rate determined around the vertical axis is filtered at frequencies above a cutoff frequency and off the filtered rate of rotation together with the speed signal a filtered first value for the roll angle is determined and where d) from the longitudinal axis rotation rate sensor determined rates of rotation before or after a Filtering at frequencies below a cutoff frequency a second Value for the roll angle is determined and the first and the second value for the roll angle to a resulting Roll angle can be added.

Furthermore, The invention relates to a measuring arrangement for determining the roll angle a single-track motor vehicle with a method mentioned above, comprising at least two yaw rate sensors for determining at least two yaw rates of the vehicle about two different axes, wherein by means of a first rotation rate sensor, a rotation rate about a vertical axis of the vehicle is determined, and by means of a second rotation rate sensor a rate of rotation about the longitudinal axis of the vehicle is determined, and wherein further calculation means are provided, which from the determined rate of rotation or from a filtered rotation rate to the Vertical axis together with a speed signal for the speed of the vehicle is a first value for determine the roll angle of the vehicle as a function of time, and wherein filter means to the filter of the yaw rate or from the yaw rate determined value for the roll angle above a cutoff frequency are provided, and wherein further filter means for filtering with the longitudinal axis rotation rate sensor determined rotation rate or from the determined rotation rates for the Rollwin angle below a cutoff frequency are provided, as well as Calculating means for determining the angle of rotation from the filtered or unfiltered longitudinal axis rotation rate, and where further adding means for adding the first and the second Yaw rate determined values for the roll angle to a resulting roll angle are provided.

A the exactest possible measurement of the skew angle when driving single-lane motor vehicles, such as motorcycles etc. is desired for various reasons. Among other things, based on the skew angle a Slope balancing of the headlight made so that the photo adapted to the inclination of the motorcycle can be.

The calculation or measurement of the skew angle by means of inertial sensors known from the prior art. So it is for example from the DE 103 50 046 A1 and the DE 10 2004 060 292 A1 Known to determine the skew angle with two or more rotation rate sensors and to calculate a resulting skew angle.

One The problem that arises with such measurements is that the yaw rate sensors depending on which axis they are in relation to determine the rate of rotation, different errors in the measurements which falsify the result such that after a short time the measurements of the determined value for the skew angle is no longer usable.

in principle provides a high-axis gyroscope linked to velocity of the vehicle, the angle of inclination (roll angle) of the vehicle, such as this will be explained in more detail below. Indeed interference is superimposed on this roll angle signal determined in this way, which are high frequency nature. According to the invention Accordingly, the signal for the roll angle low-pass filtered, to eliminate these high-frequency disturbances.

Indeed This low-pass filtering also changes the position quickly of the motor vehicle, such as fast cornering, filtered away.

Around Do not lose this information, thereby reducing the result the determined value for the skew angle will be falsified, will further the rate of rotation of the motor vehicle measured about the longitudinal axis of the vehicle.

If the yaw rate is measured around the longitudinal axis, then the skew angle can be calculated by adding up (or integrating) the yaw rate over time. By accumulating the angle changes over time, however, the errors in the measurements of the rotation rate are also added up. This causes the measured Angle deviates more and more from the actual angle with time (drift). The error (drift) arising in this measurement is of low frequency nature.

Accordingly According to the invention is determined in this way Signal for the roll angle high pass filtered to these disturbances to eliminate.

By Sum up the two filtered signals for the roll angle then results in a resulting roll angle, which is the actual Rolling angle reproduces almost exactly.

Such an approach is also still from the WO 2007/096319 A1 and the WO 2007/107935 A1 known.

in principle the second value for the roll angle, i. H. the one with the longitudinal axis rotation rate sensor detected value with a High pass filtered and then the values added / integrated, where the summation / integration can also take place before the filtering. If the invention is realized by software, it is difficult to realize an integrator in software.

It It is an object of the invention to provide a simpler software Realization of a method described at the outset or one described in the introduction To allow measuring arrangement.

These Task is characterized by a method mentioned above solved that according to the invention for the determination of the second value for the roll angle that from the longitudinal axis rotation rate sensor determined rotation rate with the cut-off frequency low-pass filtered and with a gain function proportional to the reciprocal of the cut-off frequency be strengthened.

at a concrete variant becomes the second value for the roll angle by summing up the from the longitudinal axis rotation rate sensor determined rotation rate, the filtering below the cutoff frequency done before or after the summation. With regard to the obtained Values it is irrelevant whether the rate of rotation or the rate determined from the rotation rate Angle is filtered.

at Filtering to determine the first value for the roll angle this is preferably a low-pass filtering.

One Lowpass filter attenuates a signal above its cutoff frequency and leaves this below the cutoff frequency almost unhindered by; a high pass filter attenuates a signal below its cutoff frequency and leaves this above the cutoff frequency almost unhindered by.

Around despite filtering all frequencies as evenly as possible to take into account and as accurate as possible Reconstruction of the skew angle is allowed at an advantageous variant further provided that the cutoff frequency for the low-pass filtering in step c1) or c2) and the cut-off frequency for the filtering in step d) an identical value exhibit.

If a different weighting of the frequency ranges desired can also be provided that the cutoff frequency for the low pass filtering in step c1) or c2) and the cutoff frequency for the filtering in step d) have different values. It can then but to falsifications in the investigation of the roll angle, which are then to be taken consciously into account.

In In this context, it is useful if the cut-off frequency for the low-pass filtering is lower as the cutoff frequency for high pass filtering. Naturally but also variants of the invention are possible in which the situation described is exactly the opposite.

Especially It is favorable if the sum of the transfer functions both filters is 1. This will after the summation node nearly lossless the measured roll angle signal (skew angle signal) reconstructed.

The Cutoff frequencies are the same for first order filters when the Sum of the transfer function is 1. For filters higher Order, such. This does not have to be the case with Kalman filters.

Furthermore This object is achieved with a measuring arrangement described in the introduction solved according to the invention that for determining the second value for the roll angle Low-pass filter for filtering with the longitudinal axis rotation rate sensor determined rotation rate is provided with a cutoff frequency and Furthermore, an amplifier for amplifying the low-pass filtered Values are provided with a gain function proportional to the reciprocal of the cut-off frequency is.

To Preferably Aufsummiermittel are provided by means of which the filtered or unfiltered yaw rates associated with the longitudinal yaw rate sensor be summed to a rotation angle.

Furthermore, is for filtering with the longitudinal axis rotation rate sensor determined rotation angle provided a high-pass filter.

To determine the second value for the roll angle can also be a low-pass filter for the determined with the longitudinal axis rotation rate sensor Rate of rotation to be provided with a cut-off frequency and further an amplifier for amplifying the low-pass filtered values with a reciprocal of the cutoff frequency proportional gain function is provided.

After all include the filter means for filtering the yaw rate or out the rotation rate determined value for the roll angle above a cutoff frequency a low pass filter.

in the The invention is closer to the drawing explained. In this shows

1 a single-track motor vehicle and the relevant axles,

2 the dynamic driving relationships when cornering a single-track motor vehicle,

3 a schematic representation of the basic method according to the invention with reference to a schematic representation of a measuring arrangement according to the invention,

4 exemplary frequency responses of the high-pass filter and the low-pass filter,

5 Waveforms for different banking angles, and

6 an alternative approach to determine a filtered skew angle.

1 shows a single-track motor vehicle BIK. The vertical axis with respect to the motor vehicle is denoted by VA, the longitudinal axis by LA. Also shown schematically are a vertical axis rotation rate sensor D1 for determining the rate of rotation r1 about the vertical axis VA as a function of time t and a longitudinal axis rotation rate sensor D2 for determining a rate of rotation r2 about the longitudinal axis LA of the motor vehicle as a function of time t. The skew angle is designated α. The skew angle denotes the angle against which the motorcycle is inclined when cornering against a vertical plane.

in the The following will generally discuss the determination of the skew angle α.

1) Measurement of the skew angle around the vertical axis (yaw rate):

In principle, a high-speed yaw rate sensor D1, such as a high-axis gyroscope coupled with the tacho signal, provides the roll angle or skew angle. This is explained by the following dynamic driving relationships (see also 2 ):

mit der Fahrzeugmasse m, der Fahrzeuggeschwindigkeit v und dem Kurvenradius r.The centrifugal force that occurs when cornering, can be calculated as follows:

with the vehicle mass m, the vehicle speed v and the turning radius r.

To compensate for this force, the driver places his vehicle in the direction of the center of the curve and thus generates an opposing force that follows the formula Fge = tan (α) · m · g calculated with the inclination angle α to the vertical VA. In order to calculate the current skew angle (roll angle), it is necessary that both forces are the same and equal. Accordingly applies

It it is noticeable that the skew angle is independent from the mass of the vehicle.

When passing through a curve of radius r at a velocity v, an angular velocity ω occurs:

By reshaping and inserting, the formula for the roll angle can also be represented as follows:

Taking into account that the gyroscope tilts by the angle of the motorcycle by the angle α ω gyrooutput = ω Curve · Cos (α) the following formula results for the roll angle:

However, this connection only applies when driving dynamic forces act on the motorcycle and on condition that the driver does not change the center of gravity of the motorcycle while cornering (also referred to as "hanging").

in principle can one assume that for an "ideal" Cornering as described above, the derived relationships exactly apply and also the roll angle can be calculated exactly. In Reality changes when cornering Parameters such as curve radius, steering angle, roll angle, etc. permanently, whereby the relationship shown above no longer applies exactly.

the calculated in the manner described above roll angle signal or Slant angles are thus superimposed on "disturbances", which, inter alia, for the reasons described above arise and turn out to be high-frequency or higher-frequency To expose nature.

2) Measurement of the skew angle around the longitudinal axis (roll rate):

Becomes the rate of rotation about the longitudinal axis LA by means of a rotation rate sensor D2 measured, so by adding up (or integration) of the skew angle be calculated. By summing the angle changes over the time t, however, the errors are added up. Leading to that the measured angle with the time more and more of the actual Angle deviates (drift).

Of the The error (drift) generated during this measurement is lower frequency Nature.

These Drift results from a z. B. thermally induced and therefore slow zero drift of the rotation rate sensor. Another is the Longitudinal axis of the vehicle and thus the position of the rotation rate sensor as a result of varying degrees of compression at the front and Rear axle not always parallel to the "road surface" which also leads to low-frequency interference.

In order to eliminate these errors, a method according to the invention as in 3 explained in more detail using an example explained.

to Determining the roll angle α of the motor vehicle BIK is by means of a first rotation rate sensor D1 a rotation rate r1 to one Vertical axis VA of the vehicle BIK determined.

Out the determined rotation rate (angular velocity) r1 around the vertical axis VA is combined with a speed signal v for the speed of the vehicle BIK, which z. From one Tacho signal comes, with calculation means AWE a first value for the roll angle α1 of the vehicle BIK as a function of time t is determined.

According to the invention this first value for the roll angle α1 at frequencies above a cut-off frequency fg is filtered, including as shown Low-pass filter TFP is used. This results in a low-pass filtered value for the first roll angle α1 * as a function of time t.

As already mentioned above can also already the rate of rotation r1 and then the value for the roll angle α1 * are calculated.

Furthermore, with a second rate of rotation sensor D2 the rate of rotation r2 to the Longitudinal axis LA of the vehicle BIK determined. From this Rate of rotation r2 is calculated by means of calculation SUM from the filtered rate of rotation r2 by adding or integrating a second value for Angle of rotation α2 determined. This angle of rotation α2 is below a cutoff frequency fg of a filter with a High-pass filter HPF subjected to a filtered value α2 * for the roll angle.

After all are still adder ADD for adding the first and the second yaw rate, filtered values α1 *, α2 * for the roll angle to a resulting roll angle α * intended.

4 shows a typical curve for the frequency responses of the high-pass and low-pass filters used, wherein in the preferred variant as shown both filters have the same cutoff frequency (sum of the transfer functions = 1).

This results in the following exemplary signal curves for the different roll angles α1, α1 *, α2, α2 * and the reconstructed roll angle α * as a function of time t, as in FIG 5 shown. Good to see are the roll angle α2 superimposed drift and the disturbances in the roll angle signal of α1 and the corresponding waveforms α2 *, α1 * according to the corresponding filtering.

In principle, it is possible to realize the invention in hardware. In practice, however, this will be realized in software. Since an integrator is difficult to implement here (eg if an integrator runs the risk of a value range overshoot), then as in 6 shown for determining the second filtered value α2 * for the roll angle and a low pass TFP 'for filtering the determined with the longitudinal axis rotation rate sensor D2 rotation rate r2 be provided with a cutoff frequency fg and further an amplifier VER for amplifying the low-pass filtered values with a Inverse of cutoff frequency fg proportional gain function. This corresponds to a summation / integration and high-pass filtering. There is thus no high-pass and no integrator in the software, since the system is modeled with a low pass and a gain factor.

It would be quite conceivable other filters (or filters higher Order) as a simple high and low pass filter. Important However, it is true that the sum of the transfer functions both filters should be 1. This will after the summation node almost lossless reconstructed the measured roll angle signal.

After all It should be noted that the subdivision into adders, various Filter etc. is primarily a functional and that in the Usually here a single device with appropriate software all takes over these functions. It can not be excluded Be that actual for individual functions Units are provided, although this will not be the norm.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10350046 A1 [0004]
• DE 102004060292 A1 [0004]
• WO 2007/096319 A1 [0012]
• WO 2007/107935 A1 [0012]

Claims (11)

Method for determining the roll angle (α) of a single-track motor vehicle (BIK), wherein at least two yaw rates of the vehicle are determined about two different axes by means of at least two yaw rate sensors (D1, D2), a) using a first yaw rate sensor (D1) r1) about a vertical axis (VA) of the vehicle (BIK) is determined, and b) by means of a second rotation rate sensor (D2) a rate of rotation (r2) about the longitudinal axis (LA) of the vehicle (BIK) is determined, and wherein c1) off the determined rate of rotation (r1) about the vertical axis (VA) together with a speed signal (v) for the speed of the vehicle (BIK) a first value for the roll angle (α1) of the vehicle (BIK) is determined as a function of time (t) wherein the first value for the roll angle (α1) is filtered at frequencies above a cutoff frequency (fg) to give a low pass filtered value for the first roll angle (α1 *), or c2) where the around the vertical axis (VA) averaged rate of rotation (r1) at frequencies above a cutoff frequency (fg) is filtered and from the filtered rate of rotation (r1 *) together with the speed signal (v) a filtered first value (α1 *) is determined for the roll angle, and where d) off the rotational rate (r2) determined with the longitudinal axis rotation rate sensor (D2) is determined before or after filtering at frequencies below a cutoff frequency (fg) a second, filtered value for the roll angle (α2 *) and the first and the second value (α1 *, α2 *) for the roll angle to a resulting roll angle (α *) are added, characterized in that for determining the second value (α2 *) for the roll angle of the longitudinal axis rotation rate sensor (D2) determined rotation rate (r2 ) at the cut-off frequency (fg) and amplified with a gain function proportional to the reciprocal of the cut-off frequency (fg). Method according to claim 1, characterized in that that the second value (α2 *) for the roll angle by summing up the from the longitudinal axis rotation rate sensor (D2) determined rotation rate (r2), wherein the filtering below the cut-off frequency (fg) before or after accumulation he follows. Method according to claim 1 or 2, characterized that the filtering for determining the first value (α1 *) for the roll angle is a low-pass filtering. Method according to one of claims 1 to 3, characterized in that the cutoff frequency for the Low pass filtering in step c1) or c2) and the cutoff frequency For. the filtering in step d) has an identical value (fg). Method according to one of claims 1 to 3, characterized in that the cutoff frequency for the Low pass filtering in step c1) or c2) and the cutoff frequency for the filtering in step d) different values exhibit. Method according to claim 5, characterized in that that the cutoff frequency for low pass filtering is lower is considered the cutoff frequency for high pass filtering. Method according to one of claims 1 to 6, characterized in that the sum of the transfer functions both filters is 1. Measuring arrangement for determining the roll angle (α) of a single-track motor vehicle (BIK) according to a method according to one of claims 1 to 7, comprising at least two yaw rate sensors (D1, D2) for determining at least two yaw rates of the vehicle about two different axes, wherein by means of a first yaw rate sensor (D1) a yaw rate (r1) about a vertical axis (VA) of the vehicle (BIK) is determined, and by means of a second yaw rate sensor (D2) a yaw rate (r2) about the longitudinal axis (LA) of the vehicle (BIK) is determined , and wherein calculation means (AWE) are provided, which from the determined rate of rotation (r1) or from a filtered yaw rate (r1 *) about the vertical axis (VA) together with a speed signal (v) for the speed of the vehicle (BIK) a first Determine value (α1 *) for the roll angle of the vehicle (BIK) as a function of time (t), and filter means (TFP) for filtering the rate of rotation (r1) or determined from the rate of rotation (r1) W ert (α1) for the roll angle above a cutoff frequency (fg) are provided, and wherein further filter means (HPF) for filtering determined by the longitudinal axis rotation rate sensor (D2) rotation rate (r2) or from the determined rotation rate (r2) determined values ( α2 *) are provided for the roll angle below a cutoff frequency (fg), and calculating means (SUM) for determining the rotation angle (α2 *) from the filtered or unfiltered longitudinal axis rotation rate (r2), and further wherein adding means (ADD) for adding the values (α1 *, α2 *) determined from the first and the second yaw rate are provided for the roll angle to a resulting roll angle (α *), and wherein for determining the second value (α2 *) for the roll angle a low pass (TFP ' ) is provided for filtering the rotation rate (r2) with a cut-off frequency (fg) determined with the longitudinal axis rotation rate sensor (D2) and also an amplifier (VER) for amplifying the low-pass filtered values he before the reciprocal of the cutoff frequency (fg) proportional gain function is seen. Arrangement according to claim 8, characterized summation means (SUM) are provided by means of which the filtered or unfiltered yaw rate (r2) associated with the longitudinal yaw rate sensor (D2), summed up to a rotation angle (α2 *) become. Arrangement according to claim 8 or 9, characterized that for the filtering with the longitudinal axis rotation rate sensor (D2) determined rate of rotation (r2) or rotation angle (α2 *) High pass filter (HPF) is provided. Arrangement according to one of claims 8 to 12, characterized in that the filtering means (TFP) for filtering the rate of rotation (r1) or the rate determined from the rate of rotation (r1) (α1 *) for the roll angle above a cutoff frequency (fg) comprise a low-pass filter (TFP).