JPH11211455A - Vehicle pitching angle calculation device - Google Patents

Abstract

(57) [Summary] [Problem] To detect an accurate pitching angle during rolling of a vehicle. SOLUTION: Detected vehicle heights hF at two places on the left and right of the front of the vehicle.
The pitching angle of the vehicle is calculated based on the average values of R and hFL, the average values of the vehicle height detection values hRR and hRL at the two right and left rear portions of the vehicle, and the vehicle height detection position intervals in the vehicle longitudinal direction. Thus, an accurate pitching angle can be detected even when the vehicle is rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for calculating a pitching angle of a vehicle.

[0002]

2. Description of the Related Art Based on a vehicle height hF at a front wheel position of a vehicle, a vehicle height hR at a rear wheel position, and a wheelbase length w, a pitching angle θ of the vehicle can be obtained by the following equation. .

(Equation 1) Here, the amount of change from the value in the initial state of the vehicle is substituted for the vehicle height hF at the front wheel position and the vehicle height hR at the rear wheel position. Therefore, the pitching angle θ in the initial state of the vehicle is 0 degree.

[0003] When the vehicle rolls at the time of turning, for example, the vehicle inclines in the opposite direction to the turning direction, so that the wheel in the turning direction rises and the wheel on the opposite side sinks. as a result,
Since the vehicle height value in the turning direction increases and the vehicle height value on the opposite side decreases, there is a problem that a correct pitching angle cannot be detected.

An object of the present invention is to detect an accurate pitching angle during rolling of a vehicle.

[0005]

According to a first aspect of the present invention, there is provided a vehicle height detecting means for detecting a vehicle height at two locations on the left and right at the front of the vehicle and a vehicle height at two locations on the left and right at the rear of the vehicle. Left and right 2
The pitching angle of the vehicle is calculated based on the average value of the vehicle height detection values at two locations, the average value of the vehicle height detection values at two locations on the right and left rear of the vehicle, and the mounting interval of the vehicle height detection means in the vehicle longitudinal direction. A computing means, thereby achieving the above object. (2) The second aspect of the present invention relates to the right and left sides of a vehicle front or a vehicle rear.
Vehicle height detecting means for detecting the vehicle height at two locations, the average value of the vehicle height detection values at two locations on the left and right of the front or rear of the vehicle, and the side on which the vehicle height detecting means is not installed between the front and rear of the vehicle Calculating means for calculating a pitching angle of the vehicle based on a vehicle height set value at a predetermined position of the vehicle and an interval in a vehicle longitudinal direction between the mounting position of the vehicle height detecting means and the predetermined position. To achieve. (3) The vehicle pitching angle calculation device according to claim 3, further comprising acceleration detection means for detecting a lateral acceleration of the vehicle, wherein the calculation means determines that the absolute value of the acceleration detection value exceeds a predetermined value. Is a device for calculating a pitching angle based on a vehicle height detection value immediately before an absolute value of a detected acceleration value exceeds a predetermined value. (4) The vehicle pitching angle calculating device according to claim 4, further comprising a steering angle detecting means for detecting a steering angle of the vehicle, wherein the calculating means determines that the absolute value of the detected steering angle exceeds a predetermined value. Is designed to calculate the pitching angle based on the vehicle height detection value immediately before the absolute value of the steering angle detection value exceeds a predetermined value. (5) The invention according to claim 5 is a vehicle height detecting means for detecting at least one vehicle height in front, rear, left and right of the vehicle, an acceleration detecting means for detecting acceleration in a lateral direction of the vehicle, and a vehicle height detecting value as an acceleration detecting value. Calculating means for calculating the pitching angle of the vehicle by correcting the above, thereby achieving the above object. (6) In the vehicle pitching angle calculating device according to claim 6, the vehicle height detecting means detects the angle of the suspension arm of the wheel and converts the angle into the vehicle height.

[0006]

(1) According to the first aspect of the present invention, the average value of the vehicle height detection values at the right and left two places at the front of the vehicle, the average value of the vehicle height detection values at the two right and left places at the rear of the vehicle, Since the pitching angle of the vehicle is calculated based on the vehicle height detection position interval in the vehicle front-rear direction, an accurate pitching angle can be detected even when the vehicle is rolling. (2) According to the second aspect of the invention, the average value of the two vehicle height detection values at the front and rear portions of the vehicle and the predetermined position on the vehicle front and rear portions where the vehicle height is not detected. And the pitching angle of the vehicle is calculated based on the vehicle height setting value and the distance between the vehicle height detection position and the predetermined position in the vehicle front-rear direction. An accurate pitching angle can be detected. (3) According to the third aspect of the invention, while the absolute value of the acceleration detection value exceeds the predetermined value, the pitching angle is determined based on the vehicle height detection value immediately before the absolute value of the acceleration detection value exceeds the predetermined value. Is calculated, an accurate pitching angle can be detected even when the vehicle is rolling. (4) According to the invention of claim 4, while the absolute value of the detected steering angle exceeds the predetermined value, the absolute value of the detected steering angle is based on the vehicle height detected immediately before the absolute value exceeds the predetermined value. Since the pitching angle is calculated, an accurate pitching angle can be detected even when the vehicle is rolling. (5) According to the invention of claim 5, the vehicle height is detected at least in one of the front, rear, left and right directions of the vehicle, the acceleration in the lateral direction of the vehicle is detected, and the detected vehicle height is corrected by the detected acceleration value. Because the pitching angle of was calculated.
The accurate pitching angle can be detected by the small vehicle height detecting means even when the vehicle is rolling. (6) According to the invention of claim 6, since the angle of the suspension arm of the wheel is detected and converted into the vehicle height, the vehicle height can be detected by an inexpensive method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment of the Invention FIG. 1 is a diagram showing a configuration of a first embodiment. Vehicle height sensors 1 to 4 are installed on suspension arms of the front, rear, left and right wheels of the vehicle, respectively, and detect suspension arm angles of the respective wheels and convert the angles into vehicle height values. The front right wheel height sensor 1 detects the vehicle height hFR at the right front wheel position, and the front left wheel height sensor 2 detects the vehicle height hFL at the left front wheel position. The rear wheel right vehicle height sensor 3 detects the vehicle height hRR at the right rear wheel position, and the rear wheel left vehicle height sensor 4 detects the vehicle height hRL at the left rear wheel position.

The arithmetic unit 5 is composed of a microcomputer and its peripheral parts, and calculates the pitching angle θ of the vehicle by the following equation based on the detected vehicle height at each wheel position.

(Equation 2) In Equation 2, w is the wheelbase length of the vehicle,
hFa is the average of the vehicle height values hFR and hFL at the left and right front wheel positions.

## EQU3 ## hFa = (hFR + hFL) / 2 Further, hRa is the average value of the vehicle heights hRR and hRL at the left and right rear wheel positions.

## EQU4 ## hRa = (hRR + hRL) / 2

Here, as shown in FIG. 2, the roll center when the vehicle rolls is located at a position slightly deviated from the center of the left and right wheels, that is, the center OX of the tread.
FIG. 2 shows the positional relationship among the vehicle heights hFR and hFL, the tread center OX, and the roll center at the left and right front wheel positions when the vehicle turns right. As is apparent from the figure, strictly, during rolling, the vehicle height hFc at the roll center must be obtained instead of the vehicle height value at the tread center OX, that is, the average value hFa of the left and right vehicle heights hFR and hFL.

(Equation 5) In Equation 5, T is the tread of the vehicle, and x is the distance between the tread center OX and the roll center. Therefore,
If the distance x between the tread center OX and the roll center can be detected, the vehicle height value hFc at the correct roll center position
Can be calculated.

However, since the roll center moves due to the behavior of the vehicle, it is difficult to detect or calculate the position of the roll center. However, in reality, the roll center is near the tread center OX, and it can be considered that x≪T. By transforming Equation 5,

(Equation 6) Becomes Since the second term on the right side has a very small value and can be ignored, hFc ≒ hFa. Therefore, by taking the average value hFa of the vehicle heights hFR and hFL at the left and right front wheel positions according to Equation 3, it is possible to obtain an accurate vehicle height value at the front wheel positions that is not affected by rolling of the vehicle. The same applies to the left and right rear wheels. By taking the average value hRa of the vehicle heights hRR and hRL at the left and right rear wheel positions, it is possible to obtain an accurate vehicle height value at the rear wheel position that is not affected by rolling of the vehicle.

-Modification of First Embodiment of the Invention-In the first embodiment, an example in which a total of four vehicle height sensors are installed on the left and right of the front and rear wheels of the vehicle and the pitching angle of the vehicle is calculated. Although shown, it is also possible to calculate the pitching angle by installing a vehicle height sensor only on the front wheel left and right or the rear wheel left and right.
The configuration of this modified example is omitted from the configuration shown in FIG. 1 because vehicle height sensors 1 and 2 at the left and right front wheel positions or vehicle height sensors 3 and 4 at the left and right rear wheel positions are only deleted.

Vehicle height sensors 1 and 2 are installed on the front left and right wheels,
If the vehicle height sensors 3 and 4 for the left and right rear wheels are omitted, the predetermined value h
The pitching angle θ is calculated by the following equation in which Ro is substituted.

(Equation 7)

The vehicle height sensors 3 and 4 are installed on the left and right rear wheels,
When omitting the vehicle height sensors 1 and 2 for the left and right front wheels, the predetermined value h
The pitching angle θ is calculated by the following equation in which Fo is substituted.

(Equation 8)

Second Embodiment of the Invention A lateral G sensor detects lateral acceleration of the vehicle, and determines that the vehicle is turning while the lateral acceleration exceeds a predetermined value. A second embodiment in which the pitching angle of the vehicle is calculated based on the vehicle height immediately before the lateral acceleration exceeds a predetermined value will be described.

FIG. 3 shows the configuration of the second embodiment. It should be noted that the same devices as those shown in FIG. 1 are denoted by the same reference numerals, and the description will focus on the differences. In the second embodiment, a lateral G sensor 6 is added to the configuration shown in FIG. The lateral G sensor 6 detects a lateral acceleration g of the vehicle. The arithmetic unit 5A determines that the vehicle is turning while the lateral G sensor 6 detects an acceleration g exceeding the predetermined value ± G1, as shown in FIG. Using the vehicle height values hFR, hFL, hRR, and hRL at the respective wheel positions immediately before exceeding G1, the pitching angle θ is calculated by the above equations (2) to (4).

As described above, it is also possible to calculate the pitching angle by installing a vehicle height sensor only on the left and right front wheels or on the left and right rear wheels. When the vehicle height sensors 1 and 2 are installed on the left and right front wheels and the vehicle height sensors 3 and 4 on the left and right rear wheels are omitted, the pitching angle is calculated by Expression 7. When the vehicle height sensors 3 and 4 are installed on the left and right rear wheels, and the vehicle height sensors 1 and 2 on the left and right front wheels are omitted, the pitching angle is calculated by Expression 8.

In the second embodiment, the acceleration in the lateral direction of the vehicle is detected, and it is determined that the vehicle is turning while the absolute value of the acceleration exceeds a predetermined value. Although the example in which the pitching angle is obtained based on the vehicle height immediately before the acceleration exceeds the predetermined value has been described, the steering angle of the vehicle is detected by the steering angle sensor, and the vehicle is operated while the absolute value of the steering angle exceeds the predetermined value. May be determined to be turning, and the pitching angle may be calculated based on the vehicle height immediately before the absolute value of the steering angle exceeds a predetermined value.

Third Embodiment of the Invention Since the roll angle during rolling is proportional to the acceleration in the lateral direction of the vehicle, the vehicle height value is corrected according to the acceleration in the lateral direction of the vehicle.
A third embodiment for calculating a pitching angle by obtaining an accurate vehicle height value during rolling will be described.

FIG. 5 shows the configuration of the third embodiment. This embodiment shows an example in which only the vehicle height at the right rear wheel position is detected to calculate the pitching angle. Note that the same reference numerals are given to the same devices as those shown in FIGS. 1 and 3 and the description is omitted. The vehicle height hRR at the right rear wheel position is corrected by the acceleration g in the lateral direction of the vehicle, and the vehicle height value h on the rear wheel side is calculated by the following equation.
Find Rg.

HRg = hRR-k * g In Equation 9, k is a correction coefficient. Next, the pitching angle θ is calculated from the rear wheel side vehicle height value hRg and the front wheel side vehicle height value (predetermined value) hFo.

(Equation 10)

In the third embodiment, an example is shown in which the pitching angle is obtained based on only the vehicle height at the right rear wheel position. However, only the vehicle height at the left rear wheel position and only the vehicle height at the right front wheel position are obtained. ,
The same applies to the case where the pitching angle is calculated based only on the vehicle height at the left front wheel position.

In each of the above-described embodiments and the modifications thereof, an example has been shown in which the pitching angle is calculated by detecting the vehicle height at the front wheel position and the rear wheel position. May be calculated and the pitching angle is calculated based on the vehicle height detection position interval.

In each of the above embodiments and modified examples, the front wheel right vehicle height sensor 1, the front wheel left vehicle height sensor 2, the rear wheel right vehicle height sensor 3, and the rear wheel left vehicle height sensor 4 are vehicle height detecting means. And the computing devices 5, 5A and 5B constitute computing means, and the lateral G sensor 6 constitutes acceleration detecting means.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a tread center, a roll center, and left and right vehicle heights when the vehicle is rolling.

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a detected acceleration value in a lateral direction of the vehicle and a vehicle height value.

FIG. 5 is a diagram showing a configuration of a third embodiment of the present invention.

[Explanation of symbols]

 1 front wheel right vehicle height sensor 2 front wheel left vehicle height sensor 3 rear wheel right vehicle height sensor 4 rear wheel left vehicle height sensor 5, 5A, 5B arithmetic unit 6 side G sensor

Claims (6)

[Claims] 1. A vehicle height detecting means for detecting vehicle heights at two places on the left and right sides of a front part of a vehicle and vehicle heights at two places on the left and right sides of a vehicle rear part; Computing means for computing a pitching angle of the vehicle based on an average value of vehicle height detection values at two locations on the left and right sides of a rear portion of the vehicle and an attachment interval of the vehicle height detection means in a vehicle longitudinal direction. A device for calculating the pitching angle of a vehicle. 2. A vehicle height detecting means for detecting two vehicle heights at the front and rear of the vehicle, an average value of vehicle height detection values at two front and rear portions of the vehicle, and a vehicle front. And a vehicle height set value at a predetermined position on the side where the vehicle height detection means is not installed in the rear part of the vehicle and a vehicle longitudinal direction interval between the mounting position of the vehicle height detection means and the predetermined position. Calculating means for calculating the pitching angle of the vehicle. 3. The pitching angle calculation device for a vehicle according to claim 1, further comprising: acceleration detection means for detecting a lateral acceleration of the vehicle, wherein the calculation means calculates an absolute value of the acceleration detection value. A pitching angle calculation device for a vehicle, wherein a pitching angle is calculated based on a vehicle height detection value immediately before the absolute value of the acceleration detection value exceeds the predetermined value while the acceleration value exceeds the predetermined value. 4. The vehicle pitching angle calculation device according to claim 1, further comprising: a steering angle detection unit configured to detect a steering angle of the vehicle, wherein the calculation unit determines that an absolute value of the steering angle detection value is equal to or smaller than a predetermined value. A pitching angle calculation device for a vehicle, wherein a pitching angle is calculated based on a vehicle height detection value immediately before an absolute value of a steering angle detection value exceeds a predetermined value while the steering angle exceeds a predetermined value. 5. A vehicle height detecting means for detecting at least one vehicle height in front, rear, left and right of the vehicle, an acceleration detecting means for detecting acceleration in a lateral direction of the vehicle, and a vehicle which corrects the detected vehicle height by the detected acceleration value. Calculating means for calculating the pitching angle of the vehicle. 6. The vehicle pitching angle calculating device according to claim 1, wherein said vehicle height detecting means detects an angle of a suspension arm of a wheel and converts the detected angle into a vehicle height. Characteristic vehicle pitching angle calculation device.