JPH02186238A - Measurement of turning characteristic - Google Patents

Abstract

PURPOSE:To measure characteristic for a turning without allowing a wheel to run actually by collecting a data when a lateral load corresponding to a centrifugal force is applied to left and right tires at various roll angles on a basic characteristic measuring device to determine a balancing point by a computation. CONSTITUTION:Left and right tires Tr and Te of a wheel are placed separately on a turntable 200 on a platform 13 while a body is fixed on the ground. Then, the sum of loads W1 and W2 of the left and right tires at a reference position of the wheel is kept at a fixed value W0 and the platform 13 is swing with upper and lower actuators 15 on the left and right and stopped when the platform 13 reaches a specified roll angle based on an output signal of a roll angle detector 12b. Thereafter, a load is applied to left and right tires Tr and Te from one direction with a load control of the left and right actuators 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a turning characteristic measuring method for measuring the steering characteristics when a vehicle turns.

[Prior Art and Problems to be Solved by the Invention] The wheels of a vehicle and the vehicle body are connected by a suspension, and the characteristics of the suspension are important as they have a large effect on the vibration, ride comfort, and maneuverability of the vehicle. Therefore, various measurements are performed using the characteristics of this suspension as the basic characteristics of the vehicle. One of these is the amount of so-called jack-up, which is a phenomenon in which the vehicle body lifts up due to lateral force when turning the vehicle and makes the vehicle unstable, as well as the amount of load transfer, camber angle, toe angle, tread amount, moment, and roll. It is necessary to measure mechanical characteristics such as changes in angle when manufacturing vehicles.

For example, the above-mentioned jack-up phenomenon occurs because when a lateral force necessary for turning is generated in a tire as in a swing axle type suspension, the lateral force acts as a force that lifts the vehicle body from the geometry of the suspension. Therefore, it is absolutely necessary to know the amount of this jack-up in order to know the suspension characteristics during cornering.

Conventionally, the above-mentioned characteristics regarding the amount of jerk-up when a vehicle is turning are generally obtained from data obtained by installing various measuring devices on the vehicle and measuring the distance between the vehicle body and the ground while the vehicle is actually turning. It was obtained by measuring the motion characteristics.

However, when a vehicle is actually driven, it is difficult to obtain accurate and stable data because the road surface the vehicle travels on is not necessarily flat, and various measuring devices must be mounted on the vehicle, making the measurement work difficult. The problem was that sex was troublesome.

Therefore, in view of the above-mentioned conventional problems, the present invention uses a vehicle basic characteristic measuring device installed indoors to measure the basic characteristics of a vehicle without actually driving the vehicle, thereby providing accurate and stable data relatively easily. An object of the present invention is to provide a turning characteristic measuring method that can measure the turning characteristics when a vehicle turns.

[Means to solve the problem]

In order to solve the above problems, the method for measuring turning characteristics according to the present invention is as shown in the procedure diagram of FIG. 1(a). Place it on the seesaw platform of the measuring device (step S1), move the left and right tires up and down while keeping the sum of left and right tire loads constant at the standard position to set the roll angle to a predetermined value (step S2), and then set the roll angle to a predetermined value (step S2). While keeping the sum of left and right tire loads constant, apply a lateral load to the left and right tires according to the centrifugal force during turning (step 33), and measure the roll angle and vertical displacement of the left and right tires when the lateral load is increased. The amount of roll moment and the amount of lateral displacement are respectively measured and measurement data is collected (step 34), and the roll angle is set to various values and calculations are made based on the measurement data that is repeatedly collected. The present invention is characterized in that an equilibrium point is determined (step S5), and characteristics with respect to the centrifugal force acting on the vehicle body during turning are measured using the measured values of the plurality of equilibrium points (step S36).

In order to solve the above problems, another method for measuring turning characteristics according to the present invention is as shown in the procedure diagram of FIG. Place it on the seesaw platform of the basic characteristic measuring device (step S11), and move the left and right tires up and down while keeping the sum of the left and right tire loads constant at the standard position to set the roll angle to a predetermined value (step S12). Then, while keeping the sum of the left and right tire loads constant, a lateral load is applied to the left and right tires according to the centrifugal force during turning (step 3).
13) Measure the roll angle, vertical displacement amount, and lateral displacement amount of the left and right tires when the lateral load is applied, and collect measurement data (step S14), and calculate based on the collected measurement data. It is determined whether the roll moment is balanced (step 315), and as a result of the determination,
When the roll moment is not balanced, the lateral load is increased by a predetermined value (step 513), and the measurement data collection and determination are repeated (step 515), and as a result of the determination, when the roll moment is balanced, Step 314: repeating collection of measurement data and determination of equilibrium when changing the roll angle and applying the lateral load; Step 315) is characterized in that the characteristics of the centrifugal force acting on the vehicle body during turning are measured using the measured values of the equilibrium points.

(Operation) According to the procedure of the above-mentioned method, the body of the vehicle being tested is fixed to the ground, and the left and right tires are placed on the seesaw platform of the basic characteristic measuring device, and the left and right tires are moved in the standard position. After setting the roll angle to a predetermined value by moving the left and right tires up and down while keeping the sum of the tire loads constant, the left and right tires were moved in response to the centrifugal force during turning while keeping the sum of the left and right tire loads constant. Collect measurement data by applying a lateral load and measuring the roll angle, vertical displacement, and lateral displacement of the left and right tires as the lateral load increases.
Calculation is performed based on measurement data repeatedly collected by setting the roll angle to various values to find multiple equilibrium points where the roll moment is balanced, and using the measured values of each of the multiple equilibrium points, the vehicle body is adjusted when turning. Since the characteristics with respect to the acting centrifugal force are measured, the turning characteristics when the vehicle is actually running can be easily and accurately obtained without actually driving the vehicle.

According to the procedure of the other method mentioned above, the roll moment is calculated based on the measurement data collected by measuring the roll angle, vertical displacement amount, and lateral displacement amount of the left and right tires when a lateral load is applied, and the roll moment is balanced. If the result of the determination is that the roll moment is not balanced, the lateral load is increased by a predetermined value and the measurement data collection and determination are repeated, and as a result of the determination, the roll moment is balanced. When the roll angle is changed and the lateral load is applied, measurement data is repeatedly collected and equilibrium is determined, and each measurement value at the equilibrium point is used to calculate the response to the centrifugal force acting on the vehicle body when turning. Since the characteristics are measured, the amount of measurement data to be collected can be reduced compared to the above method, and the measurement can be completed in a correspondingly shorter time.

Example C] Hereinafter, an example in which the method for measuring turning characteristics according to the present invention is applied to the measurement of the amount of jacking will be described below, but first, the behavior of the vehicle during turning will be explained based on drawings. .

Generally, when a vehicle makes a steady turn, as shown in Figure 2,
A centrifugal force acts on the vehicle body B at its center of gravity GC, and at the same time, a lateral force acts on the tires at their grounding points, resulting in a balanced state. At this time, a roll moment is generated in the vehicle body B about its roll center, but the left and right tires 71. The suspension of the Tr causes a certain displacement depending on the magnitude of the centrifugal force, and the vehicle body B rolls at an angle, and the left and right tires Tf.

A certain load corresponding to the magnitude of the centrifugal force is applied to the Tr to balance the roll moment.

In the figure, Wo is the weight of the vehicle body B on the spring S,
It is assumed that it is approximately equal to the vehicle weight W. h, h' are the vehicle's center of gravity GC, GC at the standard position before and after centrifugal force is applied due to turning
' height, T is the tored length, W, , Wt is w, +W,
=Wo! =, left and right tires Tj at the standard position where W holds true
! , the load applied to the Tr, F+, Fz is the lateral force applied to the left and right tires Tffi, Tr, respectively, ΔZ
5. ΔZ2 is the left and right tire TI when centrifugal force is applied!
, Tr suspension displacement, φ is the roll angle of the vehicle body B, and ΔP is the amount of lateral movement of the vehicle center of gravity GC when centrifugal force is applied.

When the vehicle makes a steady turn, as shown in the figure, a centrifugal force μW0 acts on the vehicle body B, and at the same time, lateral forces F, F2 act on the grounding points of the left and right tires Tl, Tr, respectively, resulting in a balanced state. At this time, the vehicle center of gravity GC' is at the height of the ground h', so a roll moment h'μW6 +W+1Δ2 is generated around the tread center, but the left and right tires Tl, Tr
The suspension causes displacements of ΔZ l and ΔZt, the roll angle of the vehicle body B becomes φ, and the loads of the left and right tires Tl and Tr become W, , W, which balances the roll moment.

The sum of the suspension displacements ΔZlyΔZ2 is zero, that is, ΔZ, +Δ2. = 0, the position h' of the vehicle center of gravity GC' is h' = h - cos φ = h, which approximately matches the position of the vehicle center of gravity GC when it is at rest.
-a, due to the suspension link arrangement and spring non-linearity, ΔZ1+ΔZ2≠0, and h'-h=Δh. Here, Δh is the amount of jackup.

In the balanced state described above, μWo=F++F'.

μW, h' + Δzwo = T (wz - Wl)
/2 holds true.

Therefore, by creating a state in which the above equation holds using the vehicle basic characteristic measuring device-L, which will be described later with reference to FIG. 5, it is possible to obtain turning characteristics equivalent to the actual vehicle state.

On the vehicle basic characteristics measuring device, the lateral force F, which corresponds to the acceleration μ, with the vehicle body B fixed to the ground.

F! is applied to the left and right tires TR, Tr, and a load W,, W that satisfies W=W, +W, is applied to both tires Tl, Tr.
The model when the vehicle body is rolled by adding z to form a state that satisfies the above equation is shown in FIG. 3.

In Fig. 3, if the roll moment generated by the centrifugal force at the center of gravity GC' of the rolled vehicle body B is Mφ, then Mφ=μW0(h h re) cos φ
...■, where hrc is the height of the center of the roll.

Also, if the moment applied from the tire side is Mφ', Δl) ) +(Fl +Fz) (h,, +Δh)
cos φ
... becomes ■. Here, T' is the tread length during roll, and ΔP is the distance between the tread center TC' during roll and the intersection of a perpendicular line passing through the roll center RC for the tread.

now, given that, Then, from formulas ■ and ■, formula ■ becomes as follows.

Mφ' = A+8 8w, (h, e+Δh) cos φ ・
...■In the model in Figure 3, the condition for equilibrium is Mφ
'+Mφ=0, so from equations ■ and ■, -ΔlWo +gW, (b, c+Δh) co
s φ−〇.

Furthermore, B= CF+ 10F! ) (hrc+Δh, )
cosφ−8w, (h, c+Δh) cosφ
...■ΔfW0 +μW, Δh cos
Since φ=0, =μWo(h+Δh) cos φ+W0 Δ2
... becomes ■.

In case 2, h- becomes irrelevant and has no effect on measurement even if it changes, so the model in Figure 3 can be changed to the equivalent model in Figure 4.

In the model shown in Figure 4, if the roll moment is Mφ, then Mφ=μwo (h+Δh) cos φ×W0Δl
...■ However, Δ2=(h+Δh) sir+ φ+Δh−((Δz
2-ΔZl) − (ΔTt +ΔT,)tan φ]...■.

In the balanced state during roll, the lateral acceleration μ is constant, and Mφ'= (Wt Wz)
...■ becomes equal to the above formula ■. Therefore, Mφ=M
By reproducing φ', the state when the actual vehicle turns can be reproduced on the basic characteristic measuring device shown in FIG.

FIG. 5 shows an example of the mechanism of the vehicle basic characteristic measuring device used in the present invention, and the illustrated measuring device is a seesaw-type force applying device having a platform that is flush with the left and right tires of the vehicle being tested. is adopted.

The force applying device has a platform 13 whose middle part is supported so as to be able to swing from side to side on a bearing frame 12 which is fixed to the upper end of a lifting shaft 11 that is guided to be able to move up and down by a guide (not shown). Vertical displacement detector 1.2
A is provided with a swing (roll) angle detector 12b on the support portion, respectively. Vertical actuators 15 that drive the platform 13 in the vertical direction are connected below the left and right intermediate portions of the platform 13, respectively. Each actuator 15 includes a hydraulic motor 15a that is servo-controlled by a servo valve, and a hydraulic motor 1.5a that is servo-controlled by a servo valve.
Each screw jack 15b is provided with a vertical displacement detector 15c.

Further, a vertically movable frame 1 is installed above the left and right intermediate portions of the plant platform 13 via a vertical load detector (not shown).
6 is provided, and on the vertically moving frame 16, there is provided a longitudinally moving frame 18 which is guided so as to be movable in the front and rear directions by hydrostatic pressure bearings. A lateral movement frame 19 is provided which is movably guided. And left and right frame 1
A rotary table 20 rotatably guided by a hydrostatic bearing is provided on the rotary table 9, and a tire of a vehicle as a specimen is placed on the rotary table 20.

The rotary table 20 is connected to the longitudinal movement frame 18 and the lateral movement frame 19 in the longitudinal direction and the lateral direction, and moves back and forth together with the longitudinal movement of the longitudinal movement frame 18, and in response to the lateral movement of the lateral movement frame 19. It is designed to move left and right at the same time.

The platform 13 also includes a longitudinal actuator 21 which is hydraulically controlled by a servo valve (not shown) and drives the longitudinal movement frame 18 in the left and right direction via a longitudinal load detector (not shown), and a longitudinal actuator 21 which is hydraulically controlled by a servo valve (not shown) and drives the longitudinal movement frame 18 in the left and right directions via a longitudinal load detector (not shown). A left and right actuator 22 drives the moving frame 19 in the left and right direction via a left and right load detector (not shown).
and a foil alignment measuring device 23 are provided. Further, a rotary actuator 24 is connected to the rotary table 20, which is hydraulically controlled by a servo valve (not shown) and drives the rotary table 20 in a rotational direction via a torque detector (not shown).

Note that 21a is a longitudinal displacement detector that detects the displacement of the longitudinally movable frame 18, 22a is a lateral displacement detector that detects the displacement of the horizontally movable frame 19, and the rotation angle of the rotary table 200 is a rotation angle (not shown). It is designed to be detected by a detector. Further, the vehicle body with left and right tires placed on the rotary table 20 is fixed by a fixing device (not shown).

The wheel alignment measuring device 23 has a sensor for detecting the steer angle, camber angle, caster angle, etc. of the tire, and outputs these measurement signals.

FIG. 6 is a block diagram showing the circuit configuration of the basic characteristic measuring device. In the same figure, 200 is a device consisting of a CPU, a display device 201 such as a CRT, a floppy disk 202, a printer 203, an input circuit 204, and a servo device. A circuit 205 is connected. The input circuit 204 is composed of an amplifier, an A/D converter, etc., and converts analog signals from each detector of the mechanism section of the basic characteristic measuring device described above with reference to FIG. 6, the foil alignment measuring device, etc. into digital signals for control. input into the device 200. The servo circuit 205 has a D/A converter that converts the digital signal from the control device 200 into an analog signal, inputs the analog signal converted by the D/A converter and the analog signal from each detector,
It consists of a servo amplifier and the like that outputs control signals for controlling each servo valve in the mechanism section of the basic characteristic measuring device described above with reference to FIG. 5, and controls the operation of the actuator.

Next, a method of measuring the amount of jack-up during turning according to the present invention using the above-mentioned basic characteristic measuring device will be described below.

First, the left and right tires Tl and Tr of the vehicle (either the front wheel or the rear wheel may be used) are placed on the rotary table 2 on the platform 13.
0, and the vehicle body is fixed to the ground using a fixing device (not shown).

Next, the sum of the left and right tire loads W+, Wt (known) at the standard position (design position) of the vehicle is set to a constant value W, (!=i
W; vehicle weight) and then turn the left and right vertical actuators l5.
The platform 13 is swung to a predetermined roll angle φ (φ1 −0) based on the output signal of the roll angle detector 12b.

to φ, ζ±10°, a predetermined step), it stops.

Thereafter, in the above state, while controlling the load on each of the upper and lower actuators 15, the left and right actuators 22 are load-controlled to apply loads F, , F from one direction to the left and right tires Tl and Tr.
, respectively. Left and right tires TI! ．． , Tr are determined as follows.

In the above formula, the value of μ is increased from O to the maximum value in predetermined steps, and the left and right tires Tl.

The lateral loads F+ and Fz applied to the Tr are sequentially increased.

At this time, the amount of vertical displacement of the bearing frame 12 is detected by the vertical displacement detector 12a, and the amount of vertical displacement of the bearing frame 12 is detected by the vertical displacement detector 12a.

The amount of vertical displacement caused by the vertical actuator l5 of the Tr is detected by the vertical displacement detector 15c, and the roll angle of the tread is detected by the roll angle detector 12b, respectively, and these are digitized by the input circuit 204 and input to the control circuit 200. Digital data on 20 floppy disks
Store in 2.

The digital data obtained as described above shows the lateral load F+,
Change in vehicle center of gravity height when increasing Fz Δh
It is used to calculate by performing the calculations in the above equations ① to [phase]. The height h of the center of gravity at the standard position used in performing this calculation is determined in advance by another method.

FIG. 7 shows Δh obtained by calculating equations (1) to (2) displayed on the display device 201 or printed out by the printer 203. In addition, in Figure 7,
The reference zero is Δh that occurs when the roll angle is φ10 at the standard position.

By the way, when the vehicle is actually running, the vehicle body is in equilibrium with the roll moment of formula (■) and roll moment (20) matching, so there exists a point where Mφ = Mφ' in the above data string obtained at each roll angle φ. It should be done.

Therefore, based on the data stored on the floppy disk, calculations of equations (2) and (2) are performed to find a point where Mφ=Mφ'.

FIG. 8 is a diagram showing the equilibrium points Mφ=Mφ' obtained on the curve of each roll angle φ by the above calculation, and the dotted line connecting the equilibrium points is a curve showing the jack amplifier characteristics when the vehicle is actually running.

Note that the vertical displacement amount Δ due to the vertical actuator 15
Z1' and ΔZ2 (based on the vertical displacement detector 15c) determine the vertical displacement amount Δ of the left and right tires Tl and Tr.
Since it is not possible to directly obtain ZllΔZ2, it is necessary to perform the following calculation to obtain it.

Δ2. = (ΔZ1 −Δ20) +ΔZ0
! ' In the formula, 2' is the distance M (known) between the tread center and the connection point of the vertical actuator 15, and ΔZ is the distance of the bearing frame 12 detected by the vertical displacement detector 12a.
is the amount of displacement in the vertical direction.

In addition, in the above-mentioned embodiment, a case was explained in which the amount of jack-up was measured, but the present invention utilizes measurement data at a plurality of equilibrium points obtained by calculation using data obtained for each roll angle described above. Various characteristics other than the amount of jackup can be measured. 9th
Figures 13 to 13 show some examples of this. Figure 9 shows changes in the load on the left and right tires during turning, Figure 10 shows changes in the camber angle of the left and right tires, Figure 11 shows changes in the toe angle, and Figure 12 shows changes in the toe angle. 13 shows the change in tread amount, and FIG. 13 shows the change in moment. Note that the camber angle and toe angle are characteristics obtained based on signals from each sensor of the wheel alignment measuring device 23.

In summary, in the present invention, first, various roll angles are set on the basic characteristic measuring device, a lateral load corresponding to the centrifugal force is applied to the left and right tires at the set angle, and data is obtained from the signals from each detector at that time. is collected in advance, and based on the collected data, calculations are performed using a data string for each set roll angle to determine an equilibrium point, and various characteristics are measured based on the data at the equilibrium point.

In this way, data is first obtained, then the equilibrium point is determined by calculation, and various characteristics are specified using the data of the determined equilibrium point, so compared to the case where the equilibrium point is found first. Characteristics can be measured in a short period of time.

In the above-mentioned embodiment, the data string is once collected on the floppy disk and then the calculation is performed to find the equilibrium point where Mφ=Mφ'.
′ may also be determined.

That is, at each roll angle, μ is 0 to G s m x
(When, Mφ=Mφ' at each horizontal weight)
When determining the equilibrium point of , the equilibrium point is found at a point where μ is small, as can be seen from FIGS. 14 and 15. Therefore, the subsequent data up to C1X is no longer necessary. Therefore, each time the lateral load is increased, the Mφ point Mφ' is calculated,
By controlling the roll angle so that it moves to the next roll angle when Mφ=Mφ', the test execution time can be shortened and a great effect can be obtained.

Note that by using the method of the present invention described above, it is also possible to detect the rollover roller angle of a vehicle.

〔effect〕

As explained above, according to the present invention, data is collected when a lateral load corresponding to centrifugal force is applied to the left and right tires at various roll angles on a basic characteristic measuring device without actually driving the vehicle. The equilibrium point is determined by calculation based on the data collected in advance or while being collected, and the characteristics during turning are measured using the data of the determined equilibrium point, making it easy to measure and accurately measure the characteristics. The extremely excellent effect of being able to perform measurements can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a procedure diagram showing the method for measuring turning characteristics according to the present invention, Fig. 2 is an explanatory diagram showing the behavior of a vehicle during turning, and Fig. 3 is a model diagram of a turning state formed on the basic characteristics measuring device. , Fig. 4 is a model diagram equivalent to Fig. 3, Fig. 5 is an exploded perspective view showing the mechanical part of the basic characteristic measuring device, Fig. 6 is a block diagram showing the circuit configuration of the basic characteristic measuring device, Fig. 7 and FIG. 8 is a graph for explaining one method of measuring the amount of jack up, FIGS. 9 to 13 are graphs illustrating various characteristics during turning that can be measured by the method of the present invention, and FIG. 14 and FIG. 15 are graphs for explaining another method of measuring the jack-up amount. B...Vehicle body, Tl, Tr...Left and right tires, 13...
・Platform, W,, W, ... left and right tire load,
μ...Centrifugal force, F,, F,...Lateral load, φ...Roll angle, ΔZI JΔ2! is the amount of vertical displacement, ΔT1,
ΔT2... Lateral displacement amount, Mφ2Mφ'... Roll moment. (b) Now! Figure Figure Figure 10 Figure 11 Figure O' Figure μ Figure max

Claims (2)

[Claims] (1) The body of the vehicle being tested is fixed to the ground, and the left and right tires are placed on the seesaw platform of the basic characteristics measuring device. The roll angle is set to a predetermined value by raising and lowering the wheel, and then, while keeping the sum of the left and right tire loads constant, a lateral load is applied to the left and right tires according to the centrifugal force during turning, increasing the lateral load. Collect measurement data by measuring the roll angle, the amount of vertical displacement, and the amount of lateral displacement of the left and right tires, respectively, when the roll angle is set to various values, and calculate based on the measurement data repeatedly collected by setting the roll angle to various values. A method for measuring turning characteristics, comprising: determining a plurality of equilibrium points where the roll moment is balanced, and measuring characteristics with respect to centrifugal force acting on a vehicle body during turning using measured values at each of the plurality of equilibrium points. (2) The body of the vehicle being tested is fixed to the ground, and the left and right tires are placed on the seesaw platform of the basic characteristics measuring device. Set the roll angle to a predetermined value by raising and lowering the wheel, then apply a lateral load to the left and right tires according to the centrifugal force during turning while keeping the sum of the left and right tire loads constant, and when the lateral load is applied. Collect measurement data by measuring the roll angle, vertical displacement amount, and lateral displacement amount of the left and right tires, calculate whether the roll moment is balanced based on the collected measurement data, and determine whether the roll moment is balanced. If the result of the determination is that the roll moment is not balanced, increase the lateral load by a predetermined value and repeat the collection and determination of the measurement data, and if the result of the determination is that the roll moment is balanced, increase the roll angle. It is characterized by repeating the collection of measurement data and determination of equilibrium when the lateral load is changed and the lateral load is applied, and the characteristics with respect to the centrifugal force acting on the vehicle body during turning are measured using the measured values at each of the equilibrium points. A method for measuring turning characteristics.