JP3619388B2 - Estimating and calculating device for height of center of gravity of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arithmetically calculate the vehicle center-of-gravity height at high speed and in real time by using a specified arithmetic expression simplified by use of the outputs of a vehicle longitudinal acceleration sensor and a plurality of pressure sensors of air suspensions as input information. SOLUTION: The mass acting on a vehicle in braking corresponds to the value M-J of subtracting an unsprung mass J from the total mass M, and the (M-J)×G of multiplying this value by an acceleration G corresponds to the vehicle advancing directional load in braking. Accordingly, the moment M01=(M-J)×G×H of multiplying this load by a vehicle center-of-gravity height H acts on the vehicle in the advancing direction. On the other hand, when the horizontal distance from each center of the front axle and the rear axle to the vehicle center-of-gravity position is Lf, Lr, and the load change quantity generated in the rear axle in braking is ΔWr, and the moment added to the vehicle is M02=ΔWr×Lf+ΔWr×Lr-ΔWr(Lf+Lr). Further, since a wheel base is L=Lf+Lr, M02= ΔWr×L. Since M01=M02, (M-J)×G×H=ΔWr×L, and the vehicle center-of-gravity height H=(ΔWr×L)/(M-J)×G. A correction coefficient (k) is provided thereon to provide H=(ΔWr×L)/(M-J)×G. Although the correction coefficient (k) is principally 1, an experimentarily proper value can be practically provided according to the kind of vehicles.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used for attitude stability control of an automobile. Although the present invention is an apparatus developed for use in preventing the rollover of commercial vehicles such as buses and trucks, the present invention can also be implemented in the same manner other than commercial vehicles. The present invention relates to an apparatus for calculating and estimating the height of the center of gravity of a vehicle simply and in a short time based on information from a vehicle direction acceleration sensor and pressure sensors of left and right axle suspensions. The present invention further relates to an apparatus for simply calculating the total vehicle weight necessary for the calculation estimation.
[0002]
[Prior art]
An apparatus for automatically controlling the posture of a vehicle in a stable direction based on the behavior of a running vehicle such as yaw or roll is about to be put into practical use. The program calculation circuit automatically estimates that there is a possibility that the vehicle may be in a slipping state while traveling, and automatically controls the brake pressure of some (or all) wheels, thereby It is possible to recover to a state where the possibility of side slip is small. For example, when the vehicle reaches a behavior unintended by the driver due to a driving operation that exceeds the characteristics of the vehicle, such as a large steering wheel operation during high-speed driving, this is automatically detected and the rear side on the outside of the roll track is detected. A stable state can be recovered by applying a brake to the wheel.
[0003]
The applicant of the present application has applied for a patent for an apparatus for performing stable control of the vehicle posture by the autoregressive method (AR method) for the posture stability control of the running vehicle (see Japanese Patent Laid-Open No. 10-315940).
[0004]
This device reasonably estimates the vehicle's behavior such as side slip or wheel / lift state by real-time calculation, and the vehicle is driven by a driver that exceeds the characteristics of the vehicle, such as a large steering wheel operation during high-speed driving. It is a device that automatically recovers to a stable state when unintended behavior is reached. More specifically, the driving operation input of the vehicle is taken as data, a numerical model holding the physical characteristics of the vehicle as numerical values is referred to, and the response of the vehicle is estimated by a transfer function. The data relating to the behavior of the vehicle given to the transfer function is self-expressed by the value obtained by multiplying the data X (k) at the time k by the weighting coefficient A (m) at each time to the past data before the time M. The response of the vehicle is calculated by the regression method (AR method), and the vehicle model is updated by the autoregression method when the load state or the passenger position is changed.
[0005]
By mounting this device on a vehicle, real-time calculation is possible with data of a small number of samples, and the estimated value can obtain an estimated value with higher accuracy in a short time compared to the conventional method using Fourier expansion. Was proved experimentally.
[0006]
The applicant of the present application has applied for Japanese Patent Application No. 10-115601 (unpublished at the time of filing this application). This prior application disclosed a device for calculating and estimating the weight of a vehicle that is indispensable for performing posture stability control.
[0007]
This prior application calculates the height of the center of gravity of the vehicle in real time, and reasonably estimates the behavior of the vehicle, such as the state of side slip or wheel lift, by real-time calculation, and automatically stabilizes the vehicle posture. is there. That is, an axle load meter that measures the weight applied to the vehicle and a gradient sensor that measures the inclination with respect to the traveling direction are mounted, and the vehicle body total weight W and the weight wf applied to the front axle are measured by the axle load meter, and the inclination angle By measuring α using a gradient sensor, the height of the center of gravity H is calculated by the following equation when a predetermined measurement condition is satisfied even when the vehicle is in operation: H = (W · Lr−Wf · L) / W tanα
W = Wf + Wr (variable)
L = Lf + Lr (constant)
However, Wr: weight applied to the rear axis L: wheel base Lf: distance from the front axis to the center of gravity position Lr: calculation from the center of gravity position to the rear axis. This calculation is performed every time the vehicle speed becomes zero and the inclination angle α exceeds a predetermined value, and the calculated value is updated and held each time. By mounting this device, attitude control adapted to a large vehicle whose behavior data includes many low frequency components can be performed with high accuracy.
[0008]
[Problems to be solved by the invention]
As a result of conducting research on the technology disclosed in the previous application, the inventors of the present application have found that it is desirable to further reduce the calculation parameters, simplify the calculation formula, and perform high-speed real-time calculation. In other words, the situation where the vehicle posture becomes unstable often occurs in a very short time, and the posture control must be performed before the unstable state expands. It was found that it is desirable to estimate and calculate the fluctuations in a shorter time.
[0009]
In principle, the value obtained by the estimation calculation by the AR method disclosed in the prior application is accurate. However, since a recursive calculation process for executing the next calculation is performed using the result of one calculation, the number of times of the regression calculation must be increased in order to increase the estimation accuracy. As the number of regression calculations increases, the calculation time increases and control for posture recovery is delayed. In order to cope with this, an expensive calculation device capable of high-speed calculation is required.
[0010]
Actually, the height of the center of gravity of the vehicle is small unless the load changes once it is measured or estimated. Is known to be the cause. It is practically meaningless to execute the calculation using the value before the occurrence of the load slip after the load slip has occurred. In addition, the weight and the position of the center of gravity fluctuate each time a vehicle is stopped at a stop on a regular bus or the like. Therefore, it is extremely effective if the height of the center of gravity of the vehicle can be measured or estimated and the value held can be constantly updated even during traveling.
[0011]
The present invention has been made in such a background, and it is an object of the present invention to improve so that the calculation formula can be estimated and calculated in a very short time by greatly simplifying the calculation formula. And An object of the present invention is to provide an apparatus capable of executing real-time calculation and control by a simple and inexpensive calculation apparatus conventionally mounted on a vehicle. Furthermore, the present invention provides an apparatus capable of estimating and calculating the total mass (M) of the vehicle, which is the basis of attitude control, accurately and in a short time by observing the fuel flow rate when the vehicle is accelerated. Objective. An object of the present invention is to provide a practical center-of-gravity height estimation calculation device capable of performing a calculation operation at high speed with simple and inexpensive software.
[0012]
[Means for Solving the Problems]
The first feature of the present invention greatly simplifies the calculation of the center of gravity height. That is, the vehicle longitudinal acceleration sensor, the pressure sensors of a plurality of air suspensions that respectively support the left and right axles, and the vehicle center-of-gravity height H from the road surface as input information using the outputs of these sensors as input information, H = k (ΔWr × L) / ((M−J) × G) (1)
And a calculation means for calculating in real time.
[0013]
However,
ΔWr is the rear axle load change during braking,
L is the wheelbase,
M is the total vehicle mass,
J is unsprung mass,
G is the acceleration during braking,
k is a correction coefficient (set for each vehicle type)
It is.
[0014]
Here, the rear load change ΔWr during braking is
ΔWr = (B × B × π) × D × E × C (2)
It is desirable to obtain as
[0015]
B is the effective radius of the air bellows of the air suspension,
D is the amount of pressure change during braking detected by the pressure sensor,
E is the number of air bellows,
C = (m + n) / m (3)
And
m is the distance from the center of the rear axis to the center of the leaf,
n is a distance from the center of the rear shaft to the center of the air bellows.
[0016]
The approximate total value M of the vehicle can be given by an operation input. In this case, it is desirable to provide an input means that allows the driver to designate one of the sizes of the load or the like divided into several stages by an input operation. The means for calculating and estimating the total mass M of the vehicle will be further described later.
[0017]
The above equation (1) will be described. The mass acting on the vehicle during braking is a value M−J obtained by subtracting the unsprung mass J from the total mass M,
Value obtained by multiplying this value by acceleration G during braking (M−J) × G
Is a load applied in the traveling direction of the vehicle during braking.
[0018]
Therefore, the moment Mo1 = (M−J) × G × H in which the vehicle is multiplied by the vehicle center-of-gravity height H in the traveling direction as shown in FIG.
Works.
[0019]
On the other hand, as shown in the figure, the distance from the center of the front axis on the horizontal line passing through the center of the front axis and the center of the rear axis to the position of the center of gravity of the vehicle is Lf, and from the position of the center of gravity of the vehicle to the center of the rear axis When the distance is Lr and the load change amount generated on the rear shaft during braking is ΔWr, the moment applied to the vehicle is
Mo2 = ΔWr × Lf + ΔWr × Lr
= ΔWr (Lf + Lr)
It becomes. In addition, the wheelbase is
L = Lf + Lr
So
Mo2 = ΔWr × L
It becomes. This moment Mo1 and Mo2 should be equal,
(M−J) × G × H = ΔWr × L
From now on, the vehicle center of gravity height H is
H = (ΔWr × L) / (M−J) × G
It becomes. This is provided with a correction coefficient k,
H = k (ΔWr × L) / (M−J) × G (1)
Is obtained. The correction coefficient k is “1” in principle, but it takes into account errors caused by sensor errors and the like, and it is desirable to set this appropriately experimentally after it has been designed once. Practically, this correction coefficient k can be set depending on the vehicle type.
[0020]
The acceleration G during braking is detected by a longitudinal acceleration sensor. The rear axle load change amount ΔWr during braking is a known value of the air bellows effective radius B of the air suspension and the number E of air bellows, and the pressure change amount D during braking of the air bellows can be detected by a pressure sensor. . Therefore, ΔWr = (B × B × π) × D × E × C (2) obtained by multiplying the effective area of the air bellows by the amount of pressure change during braking.
It can be calculated by.
[0021]
C in the equation (2) is a share ratio of the loads received by the leaf spring and the air bellows. As shown in FIG. 3, this sharing ratio is represented by m as the distance from the center of the rear axis to the center of the leaf spring, and n as the distance from the center of the rear axis to the center of the air bellows.
C = (m + n) / m (3)
It becomes.
[0022]
The calculations of the above formulas (1) to (3) are very simple calculations and can be executed in a very short time by the program calculation circuit.
[0023]
Next, the calculation of the total mass M of the vehicle, which is the second feature of the present invention, will be described. That is, the second feature of the present invention relates to the calculation of the total mass M, and the change in the vehicle speed from the time t1 to the time t2 during the start acceleration of the vehicle (v2-v1). And means for calculating from the fuel consumption from the time t1 to t2.
The vehicle works by accelerating. The work ΔU performed by the vehicle having the total mass M from time t1 to time t2 is
ΔU = {M × (v2) ² } / 2− {M × (v1) ² } / 2
= M × {(v2) ² − (v1) ² } / 2
It becomes. Therefore, the total mass M of the vehicle is
M = 2 × ΔU / {(v2) ² − (v1) ² } (4)
Can be obtained.
[0024]
Energy is required for the vehicle to perform the work of ΔU. This energy is supplied by the combustion of fuel. Therefore, if the amount of fuel consumed from time t1 to time t2 is Q, the work amount ΔU is
ΔU = K × Q where K is a proportional constant (5)
Therefore, the total mass M of the vehicle is M = 2 × K × Q / {(v2) ² − (v1) ² } (6) from the equations (4) and (5).
Thus, the vehicle total mass M can be estimated and calculated from the fuel consumption Q.
[0025]
The calculation of the total vehicle mass M is performed when a predetermined mass estimation condition is satisfied. As the estimation condition, first, it is confirmed whether or not the vehicle is stopped on a flat road. When stopping on a road with a slope, the slope resistance must be taken into account, so computation is not performed. As the next estimation condition, when the vehicle start acceleration operation is performed from a stop state on a flat road without a gradient, it is confirmed whether or not the engine rotation speed has increased from 1000 rpm to 2000 rpm by the start acceleration operation. To do.
[0026]
If the engine speed has not reached 1000 rpm, the clutch is not in a completely met state, and the fuel injection amount varies depending on the starting method, so that the calculation is not performed. If the engine speed is in the range of more than 1000 rpm and up to 2000 rpm, the next condition is whether or not the accelerator stroke exceeds 60%. If it does not exceed 60%, the fuel injection amount largely fluctuates depending on how the accelerator is depressed. If the accelerator stroke exceeds 60%, all of the mass estimation conditions are satisfied. Therefore, the total mass M of the vehicle is determined by the change in the vehicle speed from time t1 to time t2 (v2-v1) and the fuel consumption Q during that time. The operation is performed and stored.
[0027]
When braking is performed after starting on the flat road, the vehicle load according to the equation (1) is calculated using the rear axle load change ΔWr calculated from the stored vehicle total mass M and the pressure change D of the air bellows. The center of gravity height H is calculated.
[0028]
As described above, according to the present invention, the center of gravity height H of the vehicle, which is the basis of attitude control, can be calculated accurately and in a short time using a very simplified calculation formula. This can be realized simply by changing the software without adding hardware.
DETAILED DESCRIPTION OF THE INVENTION
【Example】
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a hardware system configuration diagram of the apparatus according to the embodiment of the present invention.
[0029]
The embodiment of the present invention calculates the driving state of the vehicle by using the driving operation input of the vehicle and the behavior data of the vehicle as inputs, and corrects the correction input for correcting the driving operation input and the disturbance input to the safe side according to the calculated value. A control circuit 1 for controlling the posture of the vehicle, a longitudinal acceleration sensor 2 for detecting the longitudinal acceleration, a wheel rotation sensor 3 for detecting the rotational speed of the wheel, and a clutch switch for detecting the clutch on / off state 4, a governor control circuit 5 that controls the engine and governor to detect the accelerator stroke, the engine rotation speed, and the fuel injection amount and outputs it to the control circuit 1, an air bellows pressure sensor 6 that detects the pressure of the air bellows, A lateral acceleration sensor 7 for detecting lateral acceleration, a roll rate sensor 8 for detecting roll rate, and a yaw rate for detecting yaw rate And Tosensa 9, a steering angle sensor 11 for detecting a steering angle of the steering wheel 10, and a brake pressure sensor 13 for detecting a brake pressure of the brake booster actuator 12 is provided.
[0030]
Further, as a feature of the present invention, the control circuit 1 includes a means for calculating the vehicle center-of-gravity height H in real time from the load variation ΔWr applied to the rear axle and the total vehicle mass M, and a time t1 during vehicle start acceleration. The vehicle total mass M is calculated from the change in vehicle speed (v2-v1) from time t2 to time t2 and the fuel consumption Q from time t1 to time t2, and the value is recorded and held; Means for inputting values by operation.
[0031]
Next, the operation of the embodiment of the present invention thus configured will be described.
[0032]
First, the mass estimation operation by the control circuit 1 will be described. FIG. 4 is a flowchart showing a flow of mass estimation operation by the program control circuit of the embodiment apparatus of the present invention, and FIG. 5 is a diagram for explaining mass estimation by the embodiment apparatus of the present invention.
[0033]
The control circuit 1 takes in the output of the wheel rotation sensor 3 and determines whether or not the vehicle is stopped. If the vehicle is in a stopped state, the output of the longitudinal acceleration sensor 2 is taken to determine whether the vehicle is on a flat road. If the vehicle is not stopped on a flat road, the correction according to the gradient value is required, and the estimation calculation is stopped. If the vehicle is on a flat road, the outputs of the wheel rotation sensor 3 and the clutch switch 4 are taken in, and it is determined whether or not the vehicle has started. If the vehicle has started, the engine speed and the accelerator stroke are taken from the governor control circuit 5 as shown in FIG. 5, and it is determined whether the mass estimation condition is satisfied.
[0034]
That is, if the engine rotational speed is in the range of 1000 rpm to 2000 rpm and the accelerator stroke is 60% or more, the clutch is in a completely met state, so the rapid fluctuation of the fuel injection amount that occurs in the half clutch state is There is no change in the amount of fuel injection due to the accelerator depressing operation, so the vehicle total mass M is estimated. When the engine speed is not in the range of 1000 rpm to 2000 rpm and the accelerator stroke does not reach 60%, the estimation calculation is stopped because the fuel injection amount greatly varies and the detection accuracy decreases.
[0035]
As shown in FIG. 5, the vehicle total mass M is estimated by calculating the vehicle speed v1 and the vehicle speed v2 at time t1 and time t2 from the output of the wheel rotation sensor 3, and then from the governor control circuit 5 to the time from time t1. A fuel consumption amount Q (shaded portion) is obtained by taking in the fuel injection amount up to t2 and integrating over time. The vehicle speeds v1 and v2 and the fuel consumption amount Q can be used for calculation according to the equation (6). This estimated value M is stored and held as the latest control information.
[0036]
FIGS. 6 to 9 show data obtained by actual measurements on vehicles having a gross vehicle weight (GVW) of 10 tons, 15 tons, 20 tons and 25 tons. (A) Gradient (degrees), (b) Accelerator stroke (%), (c) Engine and clutch rotational speed (rpm), (d) Torque (kg · m), (e) Fuel injection The quantity (mm ³ / st), (f) is the vehicle weight (ton) obtained by the estimation calculation, and (g) is the hold value (ton).
[0037]
When the vehicle is started as shown in FIG. 6B from a state where the vehicle is stopped on a flat road having zero gradient as shown in FIGS. 6A to 9A, the engine is rotated as shown in FIG. The speed increases and the torque increases as shown in FIG. With this acceleration operation, the fuel injection amount increases as shown in FIG.
[0038]
When the accelerator stroke exceeds 60% and the engine speed reaches the range of 1000 rpm to 2000 rpm, the control circuit 1 changes the vehicle speed from time t1 to time t2 (v2-v1) and the fuel consumption during that time To calculate the total vehicle mass. The vehicle weight obtained from the total vehicle mass is recorded as shown in FIG. 5F, and the value is recorded as a hold value as shown in FIG. All of the hold values approximate the GVW value, and the vehicle total mass (vehicle weight) approximated to the true value can be estimated and calculated from the change in the vehicle speed and the fuel consumption.
[0039]
FIG. 10 shows data obtained when the vehicle having a GVW of 25 tons is started in the same manner from a downhill stop state in the actual road running test. Thus, in the case of starting at a downward slope, since the fuel injection amount is small as shown in FIG. 5E, the estimated value is estimated to be lower than the true value. On the other hand, in the case of an upward gradient, it is estimated to be higher than the true value. Therefore, the error which arises in an estimated value can be reduced by making the start from the state stopped on the flat road into an estimation condition.
[0040]
Next, an operation for estimating the height of the center of gravity of the vehicle using the total vehicle mass thus determined will be described. FIG. 11 is a flow chart showing the flow of the center of gravity height estimation operation of the vehicle by the program control circuit of the embodiment apparatus of the present invention.
[0041]
The control circuit 1 takes in the outputs of the wheel rotation sensor 3 and the brake pressure sensor 13 and determines whether or not a brake operation has been performed. If the brake operation is being performed, the output of the air bellows pressure sensor 6 is taken in, the rear axle load change amount ΔWr is calculated by the formula (2), the held total vehicle mass M is taken in, and the formula (1) is taken. An estimation calculation of the center of gravity height H is performed.
[0042]
FIG. 12A shows the estimated value of the center of gravity height H at the high load and the flat load obtained by this estimation calculation, and FIG. 12B shows the deceleration acceleration G at that time. An average value of data calculated between time t1 and time t2 is output as an estimated value of the center of gravity height H. In the example shown in FIG. 12, an average value of 2.05 m for 4.5 seconds in the case of high load, and an average value of 1.42 m for 5.5 seconds in the case of flat load is used as the estimated value of the center of gravity height H. Is output.
[0043]
The center-of-gravity height H calculated and output in this way is used as control information for posture control. FIG. 13 is a diagram for explaining rollover (rollover) conditions as an example of posture control. In the figure, H is the height of the center of gravity, M is the total mass of the vehicle, g is the acceleration of gravity, Gy is the lateral acceleration, and T is the distance between the outer wheels of the drive wheels.
[0044]
Assuming that a vehicle having a total vehicle mass M receives lateral acceleration Gy on the left side in the traveling direction,
(T / 2) × M × Gy
The moment of acting. On the other hand, the gravitational acceleration g is directed toward the road surface at the center of gravity.
M × g × H
The load of acts. Therefore, the ratio of the distance T / 2 from the point o to the point a where the vertical line from the center of gravity is perpendicular to the road surface and the center of gravity height H acts on the force M × Gy acting in the lateral direction and the gravity from the center of gravity to the gravity direction. When the ratio is smaller than the ratio to the force M × g, that is, T / 2 × H <(M × Gy) / M × g
A rollover occurs when
[0045]
The estimated total vehicle mass M and the center-of-gravity height H are used as such control information, and it is determined whether or not the vehicle is in a rollover state.
[0046]
【The invention's effect】
As described above, according to the present invention, the total mass of the vehicle, which is the basis of attitude control, can be estimated and calculated accurately and in a short time by observing the fuel consumption when accelerating the vehicle. Then, the height of the center of gravity of the vehicle can be calculated in a short time by a very simplified calculation formula using the estimated total vehicle mass. This apparatus can be realized by inexpensive software without adding hardware.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a moment acting on a vehicle during braking according to an embodiment of the present invention.
FIG. 2 is a hardware system configuration diagram of an apparatus according to an embodiment of the present invention.
FIG. 3 is a view for explaining a rear-shaft load sharing ratio in the embodiment of the present invention.
FIG. 4 is a flowchart showing a flow of mass estimation operation by the control circuit of the embodiment apparatus of the present invention.
FIG. 5 is a diagram for explaining mass estimation by the embodiment device of the present invention.
FIG. 6 is a diagram showing data measured by actually driving a vehicle having a GVW of 10 tons on a flat road by the apparatus according to the present invention.
FIG. 7 is a diagram showing data obtained by actually measuring a vehicle having a GVW of 15 tons on a flat road by an apparatus according to an embodiment of the present invention.
FIG. 8 is a diagram showing data measured by actually driving a vehicle having a GVW of 20 tons on a flat road by the apparatus according to the present invention.
FIG. 9 is a diagram showing data obtained by actually measuring a vehicle having a GVW of 25 tons on a flat road by an apparatus according to an embodiment of the present invention.
FIG. 10 is a diagram showing data obtained by actually measuring a vehicle having a GVW of 25 tons from a downhill road by an apparatus according to an embodiment of the present invention.
FIG. 11 is a flowchart showing the flow of the center of gravity height estimation operation of the vehicle by the control circuit of the embodiment device of the present invention;
12A is a diagram showing an estimated value of the height of the center of gravity at a high load and a flat load estimated by the apparatus according to the embodiment of the present invention, and FIG. 12B is a diagram showing a deceleration acceleration at that time.
FIG. 13 is a diagram for explaining a rollover condition.
[Explanation of symbols]
1 control circuit 2 longitudinal acceleration sensor 3 wheel rotation sensor 4 clutch switch 5 governor control circuit 6 air bellows pressure sensor 7 lateral acceleration sensor 8 roll rate sensor 9 yaw rate sensor 10 steering handle 11 steering angle sensor 12 brake booster actuator 13 Brake pressure sensor

Claims (2)

An acceleration sensor in the vehicle longitudinal direction, a pressure sensor provided on a plurality of air suspensions that respectively support the left and right axles, and a vehicle center-of-gravity height H from the road surface as input information, H = k (ΔWr × L) / ((M−J) × G) (1)
As a calculation means for calculating in real time,
The rear axle load change amount ΔWr during braking is calculated from the output of the pressure sensor.
ΔWr = (B × B × π) × D × E × C (2)
An apparatus for estimating and calculating the height of the center of gravity of a vehicle, comprising means for estimating and calculating as follows .
However,
ΔWr is the rear axle load change during braking,
L is the wheelbase,
M is the total vehicle mass,
J is unsprung mass,
G is the acceleration during braking,
k is a correction coefficient (set for each vehicle type),
B is the effective radius of the air bellows of the air suspension,
D is the amount of pressure change during braking detected by the pressure sensor,
E is the number of air bellows,
C = (m + n) / m (3)
And
m is the distance from the center of the rear axis to the center of the leaf,
n is the distance from the center of the rear shaft to the center of the air bellows
And A vehicle longitudinal acceleration sensor, pressure sensors provided on a plurality of air suspensions that respectively support the left and right axles, and the vehicle center-of-gravity height H from the road surface using the outputs of these sensors as input information
H = k (ΔWr × L) / ((M−J) × G) (1)
As a calculation means for calculating in real time,
When the accelerator stroke exceeds the predetermined value and the engine rotational speed is within the predetermined rotational speed range, the change in vehicle speed from time t 1 to time t 2 during start acceleration of the vehicle (V 2 −v 1 ) and the fuel consumption Q from time t 1 to time t 2
M = 2KQ / {(v2) ² − (v1) ² }
With means to calculate by
An apparatus for estimating and calculating the height of the center of gravity of a vehicle.
However,
ΔWr is the rear axle load change during braking,
L is the wheelbase,
M is the total vehicle mass,
J is unsprung mass,
G is the acceleration during braking ,
k is a correction coefficient (set for each vehicle type)
K is a proportional constant
It is.

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