JP2008523403A - Method and apparatus for measuring the inclination angle of a single track vehicle - Google Patents

Abstract

A method and apparatus for measuring at least one tilt angle of a single track vehicle, wherein higher accuracy is achieved during measurement.
In a method for measuring at least one tilt angle of a single track vehicle, at least two rotations about two different axes of the vehicle using at least two rotation rate sensors (200, 201, 202). The rate (ωx, ωy, ωz) is measured, and at least one of the roll angle (α) and the pitch angle (β) of the vehicle is determined from at least two rotational speeds (ωx, ωy, ωz).
[Selection] Figure 1

Description

  The present invention relates to a method and apparatus for measuring at least one tilt angle of a single track vehicle.

  Conventionally, motorcycles are not equipped with a tilt angle sensor. Thus, information regarding possible future adoption is lacking. A theoretical camera-based system or a conventional inclinometer can be used to measure the tilt angle. However, these are conceived as laboratory equipment and are therefore too large and expensive to be employed for mass production of motorcycles. Furthermore, in the case of the mechanical measurement method, an adverse effect resulting from centrifugal force during the traveling of the motorcycle is added.

  From DE 102 35 378 A1 a method and device for brake control in a single track vehicle is known. There, the lateral inclination of the vehicle is measured using a yaw rate sensor. Brake control is performed in accordance with the lateral inclination.

The present invention
Measuring at least two rotation rates about two different axes of the vehicle using at least two rotation rate sensors, and determining the roll angle and / or pitch angle of the vehicle from at least two rotation rates;
The present invention relates to a method and apparatus for measuring at least one inclination angle of a single track vehicle.

At that time, the two rotation rate sensors are preferably arranged so that their measuring directions are orthogonal to each other.
One advantageous embodiment of the invention is characterized in that both rotation rates are incorporated in the measurement of the roll angle and the measurement of the pitch angle, respectively. Thereby, a higher accuracy is achieved when measuring the angle.

One advantageous embodiment of the invention is:
The vehicle roll rate and / or pitch rate is measured from at least two rotation rates, and from there the vehicle roll angle or pitch angle is measured,
It is characterized by.

One advantageous embodiment of the invention is:
Raw values for roll rate and / or pitch rate are measured using at least two rotational rate sensors;
The roll rate is determined by filtering the raw value of the roll rate, or the pitch rate is determined by filtering the raw value of the pitch rate, and the measurement of the roll angle or the pitch angle is the vehicle roll rate or pitch rate. What is done by the time integration of
It is characterized by.

This filtering removes the interference component of the signal.
One advantageous embodiment of the invention is:
The time integration measures the raw value for the roll angle and / or pitch angle of the vehicle, and the roll angle is measured by filtering the raw value of the roll angle, or the pitch value by filtering the raw value of the pitch angle. That the angle is measured,
It is characterized by.

In the last two embodiments, the order of filtering and integration is reversed.
One advantageous embodiment of the invention is characterized in that the filtering is bandpass filtering.

One advantageous embodiment of the invention is characterized in that said band filtering is second order band filtering.
One advantageous embodiment of the invention is characterized in that the measurement of the roll rate and / or the pitch rate is carried out by a numerical solution of a differential equation, in particular a system of simultaneous differential equations. These differential equations become nonlinear differential equations due to the sine function and cosine function included in the equation. In addition, these differential equations become linear differential equations.

One advantageous embodiment of the invention is characterized in that the roll rate and the pitch rate are measured using at least two rotational rate sensors.
One advantageous embodiment of the invention is:
Three rotation rate sensors measure three rotation rates around three different axes of the vehicle, and from the three rotation rates, measure the roll angle and / or pitch angle of the vehicle,
It is characterized by.

This achieves a higher accuracy of the method compared to the use of only two sensors.
One advantageous embodiment of the invention is characterized in that the roll rate, pitch rate and yaw rate are measured by means of a three rotation rate sensor.

One advantageous embodiment of the invention is:
It is characterized in that offset correction of the obtained roll angle is performed during straight traveling.

One advantageous embodiment of the invention is that at least when the steering angle of the motorcycle falls below a predetermined lower steering angle threshold, and the motorcycle speed exceeds a predetermined speed threshold. When
It is detected that the vehicle is traveling straight ahead,
It is characterized by.

The steering angle threshold is selected so that zero or almost zero steering angle can be detected.
Furthermore, the present invention provides
From at least two rotation rates for measuring at least two rotation rates around different axes of the vehicle (especially arranged perpendicular to each other with respect to their measuring direction), and at least two rotation rates Means for calculating the roll angle and / or pitch angle of
A device for measuring at least one tilt angle of a single track vehicle.

  Advantageous embodiments of the method according to the invention are also indicated as advantageous embodiments of the device according to the invention and vice versa.

  The accuracy of the method described in DE 102 35 378 A1 will be increased by the present invention. This is especially true in driving situations with large compression strokes, especially motorcycles (eg off-road motorcycles) and associated with large pitch movements.

  The background to this is the fact that the roll angle of a motorcycle can be determined with high accuracy, although not necessarily, only from the measurement of the roll rate of the motorcycle. This is related to the overlapping of pitch, roll and yaw movements in the case of motorcycles. In the case of off-road motorcycles with a large spring rate, especially roll motion (compression of the motorcycle spring during braking) is also significant. As an example of an additional large yaw movement, a sudden avoidance movement of a motorcycle in front of an obstacle will be described. In the present invention, the pitch motion of the motorcycle and optionally in addition to it the yaw motion is measured by an additional rotation rate sensor and its output is used in an evaluation algorithm along with other data. When three sensors (roll rate, pitch rate, yaw rate) are used, all kinematic relationships based on the physics of travel are considered. When only two sensors (roll rate, pitch rate) are used, motion around the vertical axis (narrow curve travel) is not considered. When only one sensor (roll rate) is used, neither pitch motion nor vertical axis motion is considered.

  According to the present invention, a rotation rate signal is measured using a micromechanical sensor, and a motorcycle tilt angle is calculated therefrom. Tilt angle is a useful parameter for future motorcycle systems, but is also useful for improving current systems. In addition or as an alternative, further pitch angles could be determined.

  In the following, the invention will be described on the basis of two embodiments. The first embodiment is based on the use of the outputs of three rotation rate sensors, and the second embodiment is based on the use of two rotation rate sensors.

First embodiment:
Three rotational rate sensors measure rotational rate components ωx, ωy, and ωz. From there, the tilt angle is estimated in combination with a motion algorithm of a numerical integrator and a second-order bandpass filter. A motorcycle is fixedly coupled with three micromechanical rotation rate sensors mounted orthogonally. The motorcycle's x-axis refers to the direction of travel, the y-axis is the horizontal axis, and the z-axis is the vertical axis. The direction of the axis shall be arranged so as to obtain a clockwise system as a motorcycle coordinate system. The rotation angle is mathematically determined in the positive direction. In doing so, the three sensors measure the next movement of the motorcycle.

The first sensor (ωx sensor) measures the rotation around the x-axis of the motorcycle, that is, roll motion or roll rate.
The second sensor (ωy sensor) measures the rotation around the y-axis of the motorcycle, that is, pitch motion or pitch rate.

The third sensor (ωz sensor) measures the rotation around the z-axis of the motorcycle, that is, the yaw motion or yaw rate.
However, the addition of the three calculated rotational speeds ωx, ωy, and ωz is not possible,
This is because the rotation of the coordinate system takes place with each rotation around one axis, and the next rotation speed is measured in the rotated coordinate system (ie using the rotated sensor). To be
Because.

Therefore, in the following description, two basic rotational speeds α ^* and β ^* based on a fixed coordinate system (inertial system) are considered. In this case, α ^* means a rotational speed around the long axis of the motorcycle (α = roll angle), and β ^* means a rotational speed around the horizontal axis of the motorcycle (β = pitch angle).

For the basic rotational speeds α ^* and β ^* , the following simultaneous differential equations described in the form of determinants hold.

From this equation, the basic rotations α and β are obtained by taking in the measured values ωx, ωy and ωz and numerical integration. The order of rotation has been changed somewhat with respect to the description using cardan angles. This has the numerical advantage (there is no singularity in the equation of motion during normal motorcycle driving) and the additional advantage that α directly indicates the roll angle. As a result, the roll angle can be calculated in principle by the numerical solution of the differential equation. It is advantageous to perform subsequent signal processing because of measurement accuracy (eg, offset error). Here, the angular velocity signals α ^* and β ^* are filtered by a secondary bandpass filter. This takes into account the fact that the actual pitch and roll movements can never be arbitrarily fast. The determination of the upper and lower limit frequencies of the bandpass filter can be determined by a test, for example, depending on the vehicle. The high frequency interference of the measurement signal above the upper limit frequency is eliminated. An offset error is seen below the lower critical frequency, but it can also be removed as above. The pitch angle and roll angle calculated in this way are required again for the calculation of the new basic rotational speeds α ^* and β ^* . This is illustrated by the feedback loop in FIG.

Second embodiment:
As an alternative to the first embodiment in which all three rotation signals ωx, ωy, and ωz existed, an algorithm based only on the rotation signals ωx and ωy can also be considered. Since the value of ωz is missing, there is no third column in the determinant of the first embodiment. Therefore, the following form is obtained.

Of course, the accuracy of the calculation is somewhat reduced because the value ωz based on rotation about the vertical axis is missing.
The process flow according to the invention is shown in FIG. In block 100, sensor signals ωx, ωy, and ωz are determined. As an alternative, only the signals ωx and ωy can be determined according to the second embodiment. Subsequently, in block 101, a numerical algorithm for solving the system of simultaneous differential equations is executed to determine the basic rotational speeds α ^* and β ^* . A time integration is then performed at block 102 to determine an unfiltered basic rotation angle ("raw signal"). Here, the basic rotation angle is a rotation angle around a fixed axis in the inertial system. This basic rotation is related to the rotation in the motorcycle coordinate system through kinematic relationships. The kinematic relationship can be obtained by applying the law on the rotational motion of solids in a relative coordinate system.

  Next, in block 103, filtering by a bandpass filter is performed. This eliminates the offset value of the basic rotation angle and high-frequency interference. As output signals of the block 103, basic rotation angles α (roll angle) and β (pitch angle) are obtained. These values are simultaneously fed back to block 101 and taken into the determinant of block 101.

  As an alternative to the flow shown in FIG. 1, bandpass filtering can be performed before integration. In this way, even if there is an offset error, it will not be taken into the integral.

  In motorcycles, if additional sensor means are provided, the offset value (ie the roll angle offset value) in the measurement of the tilt can also be used as a supplement to the filtering by the bandpass filter or as an alternative technique. It can also be measured and removed using this method.

  In the case of a four-wheeled vehicle, for example, a reset at the start of the vehicle is performed to calibrate the rotation sensor (yaw motion). In many cases, it can be assumed that the vehicle is stopped, and therefore the yaw rate value is zero. This information can be used for offset calibration by an additional reset function throughout the entire lifetime of the sensor. This situation is different for motorcycles. When starting a motorcycle, the lateral inclination angle is indefinite. This is because the motorcycle may still be supported, for example, on a side stand. Thus, the starting point is not suitable for an additional reset for lateral angle calibration. Appropriate time points for additional resets are obtained during stable straight travel.

In that case, for example, the characteristic that the motorcycle is standing vertically can be utilized in the case of stable straight traveling. As a result, the problem of offset correction shifts to the problem of detection of straight traveling. When traveling straight ahead, the steering angle is zero. If a steering angle sensor is provided, it can be detected that the vehicle is in a straight traveling state. In addition, the wheel speed can be further evaluated. In that case,
When the steering angle is zero and the speed is still greater than the speed to be defined,
Go straight ahead. Thus, it is confirmed that the motorcycle is in a state of stable straight running without being inclined in the lateral direction. With this, it is now possible to perform offset correction for tilt measurement.

  The arrangement of the device according to the invention is shown in FIG. The sensors 200, 201 and 202 measure the rotational speeds ωx, ωy and ωz and send this information to the control device or calculation means 203, which calculates the roll angle and / or pitch angle of the motorcycle. Depending on the roll angle known anyway, for example, the actuator 204 is controlled or influenced. This operation can be performed, for example, in the framework of anti-lock control for motorcycles.

1 shows the flow of an embodiment of the method according to the invention. 1 shows the configuration of an apparatus according to the present invention.

Claims (14)

At least two rotational rate sensors (200, 201, 202) are used to measure at least two rotational rates (ωx, ωy, ωz) about two different axes of the vehicle, and at least two rotational speeds From (ωx, ωy, ωz), at least one of the roll angle (α) and the pitch angle (β) of the vehicle is obtained,
A method for measuring at least one tilt angle of a single track vehicle.   2. The measuring method according to claim 1, wherein two rotation rates ([omega] x, [omega] y, [omega] z) are taken in each of the roll angle ([alpha]) measurement and the pitch angle ([beta]) measurement. From at least two rotation rates (ωx, ωy, ωz), at least one of the roll rate and pitch rate of the vehicle is measured, and from such measurement, the roll angle (α) or pitch angle (β) of the vehicle is determined. Being measured,
The measurement method according to claim 1. A raw value for at least one of a roll rate and a pitch rate is measured using the at least two rotation rate sensors (101);
The roll rate is obtained by filtering the raw value of the roll rate, or the pitch rate is obtained by filtering the raw value of the pitch rate, and the roll angle (α) or the pitch angle (β) is measured. Done by time integration of vehicle roll rate or pitch rate (102),
The measurement method according to claim 2. The time integration (102) measures the raw value for at least one of the roll angle and pitch angle of the vehicle, and the roll angle (α) is measured by filtering the raw value of the roll angle (103). Or the pitch angle (β) is measured by filtering the raw value of the pitch angle,
The measurement method according to claim 2.   The measurement method according to claim 4 or 5, wherein the filtering (103) is band filtering.   The measurement method according to claim 6, wherein the band filtering is second-order band filtering.   The measurement method according to claim 3, wherein the measurement of at least one of the roll rate and the pitch rate is performed by a numerical solution of a differential equation system (101).   The measurement method according to claim 1, wherein the roll rate and the pitch rate are measured using the at least two rotation rate sensors. Three rotation rate sensors measure three rotation rates around three different axes of the vehicle, and from the three rotation rates, at least one of a roll angle (α) and a pitch angle (β) of the vehicle Is being measured,
The measurement method according to claim 1.   The measurement method according to claim 10, wherein the roll rate, the pitch rate, and the yaw rate are measured by the three rotation rate sensor.   The measuring method according to claim 1, wherein offset correction of the obtained roll angle (α) is performed during straight traveling. At least when the vehicle steering angle is below a predetermined lower steering angle threshold, and when the speed of a single track vehicle exceeds a predetermined speed threshold,
The measuring method according to claim 12, wherein the straight traveling is detected. At least two rotation rate sensors (200, 201, 202) for measuring at least two rotation rates around different axes of the vehicle;
Calculating means (203) for determining at least one of a roll angle and a pitch angle of the vehicle from the at least two rotation rates;
An apparatus for measuring at least one tilt angle of a single track vehicle.

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