JPH06341822A - Measuring apparatus for tire slip angle - Google Patents

Abstract

PURPOSE:To measure an errorless and precise tire slip angle in the ground- touching point of a tire on the basis of a detection value obtained by detecting line-direction velocities on the central line of the tire and on the shaft line of the tire. CONSTITUTION:This measuring apparatus is featured by comprising a one- dimensional speed sensor A101 which is arranged in an arbitrary position on the central line of a tire and which detects the speed in the central-line direction of the tire, with a one-dimensional speed sensor B102 which is arranged in an arbitrary position on the shaft line of the tire and which detects the speed in the shaft-line direction of the tire and with an angle operation circuit 203 which operates a tire slip angle on the basis of information on the individual speeds detected by the one-dimensional speed sensor A101 and the one- dimensional speed sensor B102.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire slip angle measuring device for measuring a tire slip angle, which is an angle formed by a tire center line and a movement direction to the ground when a lateral slip occurs in the tire.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view showing a schematic configuration of a conventional tire slip angle measuring device. In the figure,
A two-dimensional spatial filtering type velocity vector sensor 501 is mounted on each of the four wheels. Reference numeral 502 denotes a sensor harness of the speed vector sensor 501, and 503 denotes a sensor jig board for mounting the speed vector sensor 501, which is rotatably mounted on the side surface of the wheel in the rotational axis direction of the tire 504. Also, 50
5 is a rotation restraint cable for restraining the rotation of the sensor jig board 503 so that the measurement axis of the velocity vector sensor 501 is perpendicular to the road surface, 506 is a vehicle body, 507 is a velocity vector measurement point, and 508 is slip. An angle calculation device (similar known examples include Japanese Patent Laid-Open Nos. 63-18810 and 55-21880).

FIG. 6 is a block diagram showing a schematic configuration of the slip angle computing device 508. The slip angle computing device 508 converts the signals (f ₁ , f ₂ ) from the velocity vector sensor 501 attached to each tire into a velocity signal (V
_X , V _Y ), and a slip angle (α _ER , α _EL , α _RR , α _RL ) calculated from a speed signal (V _X , V _Y ) output from the signal processing circuit 601. And an angle calculation circuit 602 for In addition,
Each velocity vector sensor 501 is attached such that the V _X signal and the V _Y signal after signal processing match the velocity in the tire center line direction and the velocity in the tire rotation axis direction in tire coordinates, respectively.

Therefore, the slip angle calculation formula by the angle 5 calculation circuit 602 is given by α = tan ^-1 V _Y / V _X (1)

FIG. 7 (a) is an explanatory view showing the relationship between a tire ground contact point A and a slip angle measurement point B in a conventional four-wheeled vehicle, and FIG. 7 (b) is a measurement example of a rear left wheel (RL). Is shown. The main symbols in the figure have the following meanings. That is, CG: vehicle center of gravity A: tire ground contact point B: slip angle measurement point CLv: vehicle body center line CLt: tire center line C: distance from vehicle body weight center CG to tire axis of rotation D: vehicle body center CG to tire center line Distance E: Offset amount from the tire center line to the sensor F: Distance from the vehicle body weight CG to the tire ground contact point A G: Distance from the vehicle body weight center CG to the velocity vector detection Vv: Vehicle body velocity vector Vt: Composite velocity vector φ: Vehicle body yaw rate εα: Slip angle.

[0006]

However, the conventional tire slip angle measuring device as described above has the following problems. That is,
In the prior art, since the speed vector sensor is attached to the side surface of the wheel, as shown in FIG. 7, the speed vector of the point B (slip angle measurement point) offset by the distance E from the point A, which is the tire ground contact point, Therefore, assuming that the velocity vector of the vehicle body is Vv, the velocity vector at the tire ground contact point A desired to be obtained is Vt, but the distance between the vehicle body weight CG and the sensor measurement point B is indicated by G. To be long. As a result, the tangential vector G · φ around the yaw axis increases due to the influence of the vehicle body yaw rate φ, so that the measured velocity vector Vs at point B already has an angular error of εα with respect to Vt at the detection stage. Become. In addition, the degree is different for all four wheels.

Further, structurally, a jig for mounting a speed sensor and a vehicle body must be modified, and sensor vibrations due to the rotation restraint mechanism of the jig cannot be sufficiently avoided. The slip angle measuring device has a problem that it is not possible to accurately measure the tire slip angle.

The present invention has been made in view of the above, and detects the respective linear velocities on the tire center line and the tire rotation axis to obtain an accurate tire slip angle without error at the tire ground contact point. The purpose is to measure.

[0009]

In order to achieve the above-mentioned object, the present invention provides a tire center line direction velocity detecting means which is arranged at an arbitrary position on the tire center line to detect the velocity in the tire center line direction. A tire rotation axis direction velocity detecting means which is arranged at an arbitrary position on the tire rotation axis direction to detect the velocity in the tire rotation axis direction, and the tire center axis direction velocity detecting means and the tire rotation axis direction velocity detecting means. The tire slip angle measuring device is provided with an angle calculating means for calculating the tire slip angle from each speed information.

[0010]

The function of the tire slip angle measuring device according to the present invention is as follows.
The speed detecting means is arranged at an arbitrary position on the tire center line and the tire rotation axis, and the angle calculating means calculates the tire slip angle at the tire ground contact point from the speed information detected by the speed detecting means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing a sensor arrangement example of a tire slip angle measuring device according to the present invention. In the figure, 101 is a one-dimensional speed sensor A, 1 as a tire center line direction speed detecting means arranged in the tire center line direction.
Reference numeral 02 denotes a one-dimensional speed sensor B as a tire rotation axis direction speed detecting means arranged in the tire rotation axis direction.
The one-dimensional speed sensor A101 and the one-dimensional speed sensor B102 are attached to the respective tires 103 of the four wheels below the suspension spring by a sensor attachment jig 104. That is, the one-dimensional speed sensor A101 and the one-dimensional speed sensor B102 for detecting the speed are mainly in the tires 103 on the front wheel right side (FR), the front wheel left side (FL), the rear wheel right side (RR), and the rear wheel left side (RL). They are arranged in the line direction and the rotation axis direction. Incidentally, 105 is a vehicle body.

FIG. 2 is a block diagram showing the configuration of the arithmetic processing unit of the tire slip angle measuring device shown in FIG. In the figure, the arithmetic processing unit 201, the speed sensor signal (S _V) the speed signal (V _X, V _Y) signal is converted to the processing circuit 202 and the velocity signal (V _X, V _Y) from the slip angle (alpha _ER, α _EL , α _RR , α _RL ) is composed of an angle calculation circuit 203 as an angle calculation means. That is, the speed sensor signals (S _V ) of each of the four wheels are connected to the input side of the signal processing circuit 202, and the speed signals (V V after the arithmetic processing corresponding to the speed sensor signals (S _V ) are processed.
_X , V _Y ) is connected to the angle calculation circuit 203. The velocity sensor signal in the tire center line direction is V _X , and the velocity sensor signal in the tire rotation axis direction is V _Y.

Next, the calculation of the slip angle will be described. One-dimensional speed sensor A1 arranged on each tire 103
The velocity sensor signal in the tire center line direction from 01 is V
_The signal processing circuit 2 is used for _X and V _Y for the velocity sensor signal in the tire rotation axis direction from the one-dimensional velocity sensor B102.
It is converted by 02. Then, this speed signal is input to the angle calculation circuit 203. In the angle calculation circuit 203, the slip angles (α _ER , α _EL , α _RR , α) are calculated from the respective speed signals based on α = tan ⁻¹ V _Y / V _X in the equation (1).
_RL ) is calculated and output.

The calculation of the slip angle will be described in more detail. That is, the slip angle in this embodiment can be calculated based on the principle described below.
FIG. 3 is a vector diagram showing the operation of this embodiment. The main symbols in the figure have the following meanings. That is, A: tire ground contact point CLv: vehicle body center line CLt: tire center line C: vehicle body weight center CG to tire rotation axis D: vehicle body weight center CG to tire center line F: vehicle body center CG to tire ground point Distance to A Vv: Vehicle speed vector Vt: Combined speed vector φ: Vehicle yaw rate α: Slip angle.

In FIG. 3, when the vehicle body centerline CLv and the tire centerline CLt are parallel and the vehicle body velocity vector is Vv and the vehicle body yaw rate is φ, the tire ground contact point A to be obtained is obtained.
Of the vehicle speed vector Vv
Is the sum of the tangent vector around the yaw axis and the point that is moved in parallel to point A. Therefore, the angle α formed by the direction of the combined velocity vector Vt and the tire center line is the slip angle.

Further, when the combined velocity vector Vt is decomposed into a velocity vector V _X in the tire center line direction and a velocity vector V _Y in the tire rotation axis direction, V _X = Vv · cos β + D · φ (2) V _Y = Vv · sin β-C · φ (3) At this time, the sign of the vehicle body yaw rate φ is C
The positive sign is the W direction (clockwise), and the sign of the slip angle α is
The first quadrant is positive and the second quadrant is negative.

Therefore, by substituting the equations (2) and (3) into the equation (1) shown in the conventional example, the equation for calculating the slip angle α is given by the equation (4).

[0018]

[Equation 1]

Since V _X does not depend on the distance C between the center of gravity CG of the vehicle and the tire ground contact point A in the tire center line direction, and V _Y does not depend on the distance D either, V _X can bring the velocity detection point to any position on the tire center line and V _Y on the tire rotation axis.

Therefore, the one-dimensional velocity sensor A10 on the tire center line and the tire rotation axis is used as the velocity vector at the tire ground contact point A, which cannot be directly detected.
1, the tire slip angle can be directly calculated because it can be accurately obtained from the detection values of the one-dimensional speed sensor B102.

In this embodiment, the vehicle body center line C
Although the case where Lv and the tire center line CLt are parallel to each other has been described, in the case where there is an angle due to the steering wheel or suspension geometry, the steering angle and the alignment amount are added as correction values to the obtained slip angle. It will be possible. Further, the one-dimensional speed sensor to be used is not limited, and a Doppler speed sensor using an ultrasonic sensor or a laser radar, or a spatial filtering speed sensor that is currently put into practical use may be used.

FIG. 4 is an explanatory view showing another example of sensor arrangement of the tire slip angle measuring device. In the figure, the configurations of the one-dimensional speed sensor A101 and the one-dimensional speed sensor B102 are the same as those in FIG. However, for non-steered wheels such as rear wheels, when the geometry of the left and right wheels is symmetrical with respect to the center of gravity of the vehicle and the alignment change due to the reaction force from the road surface is small, Since the speeds in the tire rotation axis direction can be regarded as equivalent, the one-dimensional speed sensor is attached to either wheel.
Further, when the speed sensor cannot be mounted in the regular direction due to the limitation of the mounting space of the one-dimensional speed sensor, the speed sensor can be mounted in the opposite direction of the tire 103 on the mounting line. In this case, the sign of the detected speed signal is reversed to deal with it.

Therefore, the operation based on the above-mentioned configuration is such that only one set of the detection signal lines in FIG. 1 and FIG. 2 is reduced, and therefore the same processing is executed to calculate an accurate slip angle. You can In addition, the cost of the measurement system can be reduced as the number of parts is reduced.

As described above, according to the above embodiment, the one-dimensional velocity sensor is attached to the suspension arm or the like at any position on the tire center line and the tire rotation axis using a simple attachment jig. However, since the tire slip angle at the tire ground contact point is directly calculated from the speed value obtained through the sensor, it is not necessary to modify the sensor mounting jig board having a rotating mechanism, the vehicle body, and the wheel. The original performance of the vehicle body is not impaired. Also,
Since it is possible to eliminate the error due to the vibration of the speed sensor, it is possible to directly and accurately measure the tire slip angle at the tire ground contact point, which is physically difficult.

Further, since the speed sensor may be an inexpensive one-dimensional type that is generally used, the cost of the measuring system can be reduced, and the mounting position can be arbitrarily selected, so that it can be easily applied to a complicated suspension. Can be installed.

[0026]

As described above, according to the slip angle measuring device of the present invention, the tire center line direction velocity detecting means is arranged at an arbitrary position on the tire center line to detect the velocity in the tire center line direction. A tire rotation axis direction velocity detecting means which is arranged at an arbitrary position on the tire rotation axis direction to detect the velocity in the tire rotation axis direction, and the tire center axis direction velocity detecting means and the tire rotation axis direction velocity detecting means. Since the tire slip angle is calculated from each speed information, the linear velocities of the tire center line and the tire rotation axis are detected, and accurate tire slip without error at the tire ground contact point is detected. The angle can be measured.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a sensor arrangement example of a tire slip angle measuring device according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an arithmetic processing unit in the tire slip angle measuring device according to the present invention.

FIG. 3 is an explanatory view showing the operation of the tire slip angle measuring device according to the present invention.

FIG. 4 is an explanatory view showing another sensor arrangement example of the tire slip angle measuring device according to the present invention.

FIG. 5 is an explanatory diagram showing a schematic configuration of a conventional tire slip angle measuring device.

6 is a block diagram showing a schematic configuration of the slip angle computing device shown in FIG.

FIG. 7 is an explanatory diagram showing a relationship between a tire ground contact point A and a slip angle measurement point B in a conventional four-wheeled vehicle.

[Explanation of symbols]

 101 one-dimensional speed sensor A 102 one-dimensional speed sensor B 103 tire 201 arithmetic processing unit 202 signal processing circuit 203 angle arithmetic circuit

Claims (1)

[Claims] 1. A tire center line direction speed detecting means arranged at an arbitrary position on a tire center line to detect a speed in the tire center line direction, and a tire center line direction speed detecting means arranged at an arbitrary position on a tire rotation axis line. And a tire rotation axis direction speed detection means, and a tire center line direction speed detection means and an angle calculation means for calculating a tire slip angle from each speed information detected by the tire rotation axis direction speed detection means. A tire slip angle measuring device characterized by: