JP3473292B2 - Vehicle rollover prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for preventing a vehicle from turning, sideways with which it is possible to simplify the control, suppress the costs, and take a safety measure at an early stage. SOLUTION: A sideways-turning preventive device is composed of a load sensing means 2 to sense the loads on a left and a right wheel, a load varying speed sensing means 4 to sense the load varying speed of the right and left wheels, a safety device 3 to take a safety measure for preventing the vehicle from tumbling sideways, and a control means 1 which actuates the safety device 3 if the sensing result based upon the sensing information given by the load sensing means 2 is such that the load on one of the wheels is under the specified value when the attainment of the specified varying speed by the load varying speed of either wheel in the direction of load decrement is sensed on the basis of the sensing information given by the sensing means 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle rollover prevention device for preventing rollover of a vehicle, and more particularly to a vehicle rollover prevention device suitable for use in a vehicle such as a truck whose center of gravity changes in height depending on its loaded state. .

[0002]

2. Description of the Related Art Conventionally, various vehicle rollover preventive devices have been proposed as safety measures for preventing rollover of a vehicle. In these conventional vehicle rollover prevention devices, based on detection signals from a load sensor, a vehicle speed sensor, a steering sensor, etc., a vehicle speed is estimated by fuzzy reasoning, etc. When the estimated limit vehicle speed is exceeded, an alarm device is activated or the accelerator is automatically loosened to prevent the vehicle from rolling over.

As such a vehicle rollover prevention device, for example, there is a technique described in Japanese Patent Laid-Open No. 4-191181.

[0004]

However, in the technique described in the above publication, the warning means is activated when the vehicle traveling speed exceeds the estimated limit vehicle speed.
Since the limit speed is estimated by the absolute value of the load detected by the load sensor, the alarm device does not operate until immediately before the vehicle rolls over, and it is difficult to give an alarm at an appropriate timing. There is a problem that the alarm accuracy is not good.

Further, in such a conventional technique, there is a problem that the control becomes complicated because the limit vehicle speed is estimated by fuzzy reasoning or the like. Moreover, since a plurality of sensors such as a load sensor, a vehicle speed sensor, and a steering sensor are used, there is a problem that the cost becomes high. The present invention is
The present invention has been made in view of such a problem, and provides a vehicle rollover prevention device that simplifies control, can reduce costs, and can implement safety measures at an early stage. With the goal.

[0006]

Therefore, the vehicle rollover prevention device of the present invention according to claim 1 detects the load of the left and right wheels and the load change speed of the left and right wheels. A load change speed detecting means, a safety device for taking a safety measure to prevent the vehicle from rolling over, and a load change speed of one of the left and right wheels based on the detection information from the load change speed detecting means. When it is detected that the predetermined change speed in the decreasing direction is reached, it is detected that the load of the one wheel is less than or equal to the predetermined load based on the detection information from the load detection means. and a control means for operating, control means,該荷heavy rate of change substantially
When it is detected that the value has decreased to 0, the predetermined change speed is set.
Is the smallest of the plurality of predetermined change rates provided in advance
Set the initial predetermined change speed and set it as the predetermined load.
Set an initial set load corresponding to the initial predetermined change speed.
It is characterized by being configured as follows.

[0007] the vehicle rollover prevention system of the present invention according to claim 2, a load detecting means for detecting a load of the left and right wheels, the left
Load change speed detection hand that detects the load change speed of the right wheel
Steps and safety devices that take safety measures to prevent the vehicle from rolling over
And based on the detection information from the load change speed detection means
The rate of change of load on either the left or right wheel is
When it is detected that the predetermined change speed in the lesser direction is reached
First, based on the detection information from the load detecting means,
When it is detected that the wheel load of
A control means for operating the safety device, wherein the control means has a plurality of combinations of the predetermined change speed and the predetermined load, and the predetermined change speed and the predetermined load respectively include a first change speed and a first change speed. In the case where one load is set, the load change speed of the one of the left and right wheels is equal to or higher than the first change speed in the decreasing direction of the load, and the load of the one wheel is larger than the first load. When it is detected, a second change speed that is faster than the first change speed is set as the predetermined change speed, and the predetermined load is set as the predetermined load.
It is characterized in that a second load larger than the first load is set.

According to a third aspect of the present invention, there is provided the vehicle overturn prevention device according to the second aspect, wherein the control means detects the predetermined change when the load change speed is reduced to substantially zero. A minimum initial predetermined change speed is set as a speed among a plurality of predetermined change speeds set in advance, and an initial set load corresponding to the initial predetermined change speed is set as the predetermined load. Is characterized by.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 are for explaining a vehicle rollover prevention device as one embodiment of the present invention. As shown in FIG. 1, a vehicle (not shown) to which the present device is applied is provided with a suspension load sensor (load sensor) 2 as load detecting means. This load sensor 2 is a sensor for detecting the ground contact load of each of the left and right wheels on the rear wheel side of the vehicle. Based on the detection information from the load sensor 2, the actual ground load of each of the left and right wheels is detected. It has become.

Further, the present apparatus is provided with load change speed detecting means 4 for detecting the change speed of the ground load on these left and right wheels. As described above, the load change speed detecting means 4 detects the change speed of the ground load of the left and right wheels, that is, the rate of change of the ground load per unit time. It is possible to detect whether it is sudden or gentle.

In this embodiment, the load change speed detecting means 4 is not provided independently of the load sensor 2, and the load change speed detecting means 4 differentiates the detection information from the load sensor 2 with respect to time. This is configured as a load change speed calculation means for calculating the load change speed. Further, the load sensor 2 actually detects the suspension load applied to each wheel, and strictly speaking does not detect the ground load including the weight of the wheel, but the suspension load and the ground load are not detected. Since the difference between the two is virtually negligible, the load applied to the suspension and the ground contact load of the wheel are treated as synonymous.

Reference numeral 1 is a control means. The control means 1 has a rollover risk level (roll) to predict the risk of rollover of the vehicle based on the detection information from the load sensor 2 and the load change speed detection means 4. A determination unit 5 is provided for determining the degree of danger. The operation of the safety device 3 is controlled based on the determination result of the determination unit 5.

Although FIG. 1 shows only one side of the load sensor 2 for the left and right wheels, in reality, the load sensor 2 and the load change detecting means 4 are provided on the other side as well. The section 5 performs similar control processing on the detection output from each of the left and right wheels. A map as shown in FIG. 3 is stored in the judging unit 5, and information from the load sensor 2 and the load change speed detecting means 4 is taken into the judging unit 5, and the ground load W and the load change at that time are taken. From the relationship with the speed U, it is determined whether or not there is a risk of the vehicle rolling over.

That is, in the determination unit 5, the ground load W on the inner wheel side decreases when the vehicle turns, and the change speed U thereof is set in advance in advance. changing speed) U _L (U ₁ ~U reads vertical load W of the wheel when it is detected that reaches _7), the vertical load W value load change rate threshold U _L at this time
When it is determined that the load is less than or equal to a predetermined load W _L (W _{1 to} W ₇ ), which is set in advance, the safety device 3 is activated because the vehicle is in danger of rollover. As described above, in the present device, the ground contact state of the turning inner wheel is monitored by evaluating the load change speed U and the ground load W of the wheel on the side where the ground load W decreases. In order to make the determination more certain, the steering angle sensor or the like may be used together to identify the turning inner wheel, and then the above determination may be performed.

Further, the safety device 3 takes safety measures to prevent the vehicle from rolling over. For example, an alarm device for issuing an alarm, a driving force suppressing device for suppressing the driving force of the vehicle, and a roll rigidity of the suspension are provided. It is a roll rigidity adjusting device for adjustment. Now, the map shown in FIG. 3 will be described. This map shows that the experimentally obtained load change speed (decrease speed) U and the ground contact load W in the direction in which the load decreases.
From this relationship, the area for determining the degree of rollover risk of the vehicle is set, and each plot point in FIG. 3 shows the load while changing the load capacity of the luggage, the height of the center of gravity, the steering operation, etc. at a predetermined speed. It is a value obtained by actually measuring the relationship between the changing speed U and the ground contact load W.

In FIG. 3, the vertical axis represents the ground load W and the horizontal axis represents the load change speed U, U _{1 to} U ₇ are load change speed threshold values, and W _{1 to} W ₇ are load changes. It is a predetermined load corresponding to the speed thresholds U _{1 to} U ₇ . Note that FIG.
Then, the ground contact load W when each load change speed threshold _UL is reached is indicated by ○, ● when no load is loaded, and by □, ■ when load is loaded. Further, when the lift of the inner wheel side (ground load = 0) occurs, it is indicated by ●, ■, and when it does not occur, it is indicated by ○ and □.

Then, as shown in the map of FIG.
When the load change speed U is small (that is, when the rate of decrease of the ground contact load is small), the wheel does not lift much even when the ground contact load W is small, but when the load change speed U is large (that is, the ground contact load is small). Indicates that the wheel lift is likely to occur even when the ground contact load W is large.

Here, when a boundary line between the case where the wheel lift occurs and the case where the wheel lift does not occur is drawn in FIG. 3, it becomes as shown by a line a. The ground contact load W indicated by the line a is a limit ground contact load W at which a wheel lift does not occur for each load change speed U, and a region below the line a indicates a risk of vehicle rollover. It can be said that there is an area. And
The determination unit 5 sets a load change speed for determining the risk of rollover of the vehicle in a plurality of stages (U _{1 to} U ₇ ), and a threshold value (predetermined load) W of the ground load W corresponding to each of these stages.
_L (W ₁ ~W ₇₎ has been set.

Therefore, the determination unit 5 determines that the load change speed U detected at regular intervals is greater than the load change speed U out of the load change speed threshold U _L set in stages (the load decreases). The threshold value _UL that is closest to the load change speed U, and the load change speed U is the threshold value _UL.
It is designed to determine whether the ground load W at the time of reaching the predetermined load is less than or equal to a predetermined load W _L corresponding to the threshold U _L , and when it is less than or equal to the predetermined load W _L , the safety device 3 is operated, If the load is not less than the predetermined load W _L , the safety device 3 is not activated. Here, since the inner wheel on the rear wheel side is most likely to lift, the suspension load (that is, the ground load) W on the rear wheel side is read.

At this time, the ground contact load W is the predetermined load W.
Greater than _L, and if it is determined that there is no risk of rollover, the threshold of the load change rate U, the threshold U _L is set to the threshold value U _{L + 1} of one step larger than the load change rate U of the vehicle When the threshold value U _{L + 1} is reached, the ground contact load W is compared with a predetermined load W _{L + 1} set according to the threshold value U _{L + 1} to determine whether there is a risk of rollover. ing.

Also in this case, if the ground contact load W is larger than the predetermined load W _{L + 1} , the threshold value of the load change speed U is further set to the threshold value U _{L + 2} which is one step larger, and the above-mentioned value is set. Such a determination is made. That is, the determining unit 5, each of the first variation rate of load change rate threshold U _L and the predetermined load W _L (e.g., load change rate threshold U ₁₎ and the first load (e.g., predetermined load W ₁₎
When it is detected that the load change speed U is more than the first change speed U ₁ in the decreasing direction and the ground load is larger than the first load W ₁ , the load change speed threshold value _UL is set. A second changing speed (for example, a load changing speed threshold U ₂ ) faster than the first changing speed U ₁ is set, and a second load corresponding to the second changing speed U ₂ as a predetermined load W _L (for example, A predetermined load W ₂ ) is set.

This is because the load change speed U decreases in the first direction.
When it is detected that the change speed U ₁ or more and the ground load is larger than the first load W ₁ , the determination unit 5 does not operate the safety device 3 because the risk of rollover is small, but thereafter, the load change speed U This is because if the load further increases, the ground load W at that time is referred to so as to reliably determine the risk of the vehicle overturning. That is, the load change rate U is the first change rate U ₁
First, the vehicle rollover determination
If the first load W ₁ corresponding to the changing speed U ₁ is used as it is, it may be determined that the rollover risk is small even if the rollover risk is actually high, and the determination accuracy is deteriorated. Because it will be.

Further, in this way, the load change speed threshold U _L ,
The sequential updating of the predetermined load W _L has the following significance. That is, when the characteristic of FIG. 3 is a simple map, the determination is made regardless of the increasing / decreasing tendency of the load change speed U. For example, even if the load change speed U is decreasing in the convergent direction, If the region is below the line a, it is determined that there is a risk of rollover, but if the load change rate U is decreasing in the direction of convergence, it is in the process of transitioning to a stable state and the risk of rollover is high. Is small, resulting in an erroneous determination. Therefore, in the present embodiment, the threshold value for the load change speed U is increased stepwise, and if the load change speed U decreases in the converging direction as a result, the updated threshold value is not exceeded, and Since such an erroneous determination can be reliably prevented, high accuracy can be obtained.

By the way, the update to the smaller side of the load change speed threshold U _L is performed only when the load change speed U becomes equal to or lower than the initialization reference value. That is, when it is detected that the load change speed U has decreased to the initialization reference value or less (U≈0), the determination unit 5 determines a plurality of load change speed thresholds U _{L that} are provided in advance as the load change speed threshold U _L. with the smallest initial predetermined change speed U ₁ of the _L is set, predetermined load W _L
As the initial set load W corresponding to the initial predetermined change speed U _{1.
Since 1} is set, it is possible to predict the rollover risk in a stable manner and to increase the prediction sensitivity after the load change speed converges.

Here, a specific example of the determination of the rollover risk of the vehicle will be described. First, the ground load W detected by the load detection means 2 and the load change speed detection means 4
The determination of the rollover risk in the case where the load change rate U detected by is a value as indicated by point A in FIG. 3 will be described with reference to FIG. In addition, in FIG. 4, a curve A indicates that the ground load W of the inner wheel on the rear wheel side decreases when the vehicle turns,
As a result, it is an example showing the change over time of the ground contact load when a lift occurs, and the vertical axis indicates the ground contact load W of the rear wheel side inner ring and the horizontal axis indicates the time. Therefore, the slope of the curve A indicates the load change rate U.

In FIG. 4, point a is when the load change speed U reaches the load change speed threshold U ₁ , and the ground load W at that time is larger than the predetermined load W ₁ shown by the broken line in FIG. Therefore, the safety device 3 is not operated because there is no danger of rollover. On the other hand, in FIG. 4, point b is when the load change speed U reaches the load change speed threshold U ₂ , and the ground load W at that time is more than the predetermined load W ₂ shown by the broken line in FIG. Since it is small, the safety device 3 is activated because there is a risk of rollover.

Next, in the case where the ground contact load W detected by the load detecting means 2 and the load changing speed U detected by the load changing speed detecting means 4 are values shown by point B in FIG. The determination of the rollover risk will be described with reference to FIG. In addition, in FIG. 5, a curve A is an example showing a temporal change of the ground load when the ground load W of the inner wheel on the rear wheel side decreases and then becomes constant when the vehicle turns, and as a result, the lift does not occur. The vertical axis indicates the ground contact load of the inner wheel on the rear wheel side, and the horizontal axis indicates the time. Therefore, the slope of the curve A indicates the load change rate U.
Further, the constant ground load W indicates that the vehicle is making a steady turn.

In FIG. 5, point a is when the load change speed U reaches the load change speed threshold value U ₁ , and the ground load W at that time is larger than the predetermined load W ₁ shown by the broken line in FIG. Therefore, the safety device 3 is not operated because there is no danger of rollover. At point b, the load change speed U is the load change speed threshold U
₂ is reached, and the ground load W at that time is shown in FIG.
Since the load is larger than the predetermined load W ₂ indicated by the broken line, the safety device 3 is not operated because there is no danger of rollover.

Point c is when the load change speed U reaches the load change speed threshold value U ₃ , and the ground load W at that time is
₃ is larger than the predetermined load W ₃ indicated by the broken line in FIG. 3, the safety device 3 is not operated because there is no danger of rollover. In this case, as described above, in any case, the predetermined load W
_Since it is larger than ₃ , safety device 3 is not activated. Further, since the load change speed U has not reached the load change speed threshold U ₄ , the other rollover risk levels are not determined, and the safety device 3 is not operated because there is no risk of rollover.

The vehicle rollover prevention device as one embodiment of the present invention is configured as described above, and the control by this device is performed as shown in the flow chart of FIG. First, in step S10, the current load change rate U is compared with the currently recognized predetermined change rate U _L , and as a result, the load change rate U is larger than the predetermined change rate U _L (of the ground load). If the rate of change in the decreasing direction is high), the process proceeds to step S20. Then, in step S20, it is determined whether or not the current ground contact load W is smaller than the predetermined load W _L.

As a result of this judgment, the ground contact load W is the predetermined load W.
_LIf it is smaller than, the rollover risk of the vehicle is high,
Proceeding to step S40, the safety device 4,
For example, the alarm device is activated and the process returns. On the other hand,
At step S20, the ground load W is the predetermined load W_LGreater than
If it is determined that the predetermined load
Heavy W_LAnd the predetermined change rate U_LEach one step larger
Constant load W_L(W_L= W_{L + 1}) And the predetermined change rate U_L(U
_L= U _{L + 1}) And returns to step S10.

By the way, if the load changing speed U is determined not to reach the predetermined changing speed U _L in step S10 after returning from step S30 to step S10, the process proceeds to step S50. The current load change rate U is read and it is determined whether the load change rate U is substantially equal to 0 (U≈0). As a result of this determination, when the load change speed U is substantially equal to 0, it is considered that the running state of the vehicle is the steady state (that is, the straight traveling state or the steady turning state), and therefore the load change thereafter. The predetermined load W _L and the predetermined change speed U _L are reset to the initial predetermined load W ₁ and the initial predetermined change speed U ₁ to correspond to the change in the speed, and the process returns to B.

Therefore, according to this vehicle rollover prevention device, the control means 1 operates the safety device 3 based on the detection signal from only the suspension load sensor 2, so that the number of types of sensors required is small. There is an advantage that the cost can be reduced. Further, in order to determine whether or not the risk of rollover of the vehicle is high by using the predetermined change speed U _L and the predetermined load W _L as threshold values, the rollover of the vehicle is prevented even when the steer characteristics and the height of the center of gravity of the vehicle are different. There is also an advantage that the prediction can be made at an early timing, the safety device 3 can be operated at an accurate timing, and it is not always necessary to use fuzzy reasoning, and the control can be simplified.

After it is judged that the load change speed U is the predetermined change speed U _L or more in the decreasing direction but the risk of rollover is small, the load change speed threshold U _L which is a reference value for rollover prediction is set to one. Since the predetermined change speed U _{L + 1} is updated in steps, and the predetermined load is also set to the predetermined load W _{L + 1} corresponding to the updated predetermined change speed U _{L + 1} , even when the load change speed U further increases. The risk of rollover can be accurately determined, and the load change speed U is the previous predetermined change speed U.
Under the condition that it decreases in the direction of convergence in the region of _{L + 1} or more (the risk of rollover is small because the load change speed U decreases)
There is also an advantage that the accuracy of determination is high because the risk of rollover is not predicted by mistake.

Further, after the load change rate threshold U _L which is a reference value for predicting the risk of rollover is increased one step is
Since the load change speed threshold U _L is not initialized until the load change speed U becomes equal to or less than the initialization reference value (here, the load change speed U becomes substantially 0), stable prediction can be realized, and the load change can be realized. There is an advantage that the prediction sensitivity after the speed U converges can be set high.

[0036]

As described above in detail, according to the vehicle rollover prevention device of the present invention as set forth in claim 1, since the risk of rollover is predicted based on the wheel load and the load change speed, the height of the center of gravity is increased. There is an advantage in that accurate prediction can be performed at an early stage regardless of whether or not In particular, the basis for predicting the risk of rollover
After increasing the prescribed rate of change, which is a quasi value,
Since the predetermined change speed is not initialized until the degree becomes almost 0,
Stable prediction can be realized, and after the load change speed converges
There is an advantage that the prediction sensitivity can be set high. Claim 2
According to the vehicle rollover prevention device of the present invention described, after it is determined that the load change speed is the first predetermined change speed in the decreasing direction or more but the risk of rollover is small, a predetermined reference value for rollover prediction is obtained. Since the changing speed is set to the second predetermined changing speed,
Further, there is an advantage that the risk of rollover can be accurately determined even when the load change speed increases.

According to the vehicle rollover prevention device of the third aspect of the present invention, after the predetermined change speed, which is the reference value for predicting the risk of rollover, is increased, the load change speed becomes substantially zero. Since the predetermined change speed is not initialized, there is an advantage that stable prediction can be realized and the prediction sensitivity after the load change speed converges can be set high.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a vehicle rollover prevention device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining control of a vehicle rollover prevention device according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a predetermined change speed and a predetermined load of the vehicle rollover prevention device according to the embodiment of the present invention.

FIG. 4 is a diagram for explaining the timing of operating the safety device by the control means of the vehicle rollover prevention device according to the embodiment of the present invention.

FIG. 5 is a diagram for explaining the timing of operating the safety device by the control means of the vehicle rollover prevention device according to the embodiment of the present invention.

[Explanation of symbols]

1 control means 2 Suspension load sensor (load detection means) 3 safety devices 4 Load change speed detection means 5 Judgment section

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Claims (3)

(57) [Claims] 1. A load detecting means for detecting a load on the left and right wheels, a load changing speed detecting means for detecting a load changing speed on the left and right wheels, and a safety device for taking a safety measure to prevent the vehicle from rolling over. Detecting the load when it is detected that the load changing speed of either the left or right wheel has reached a predetermined changing speed in the decreasing direction of the load based on the detection information from the load changing speed detecting means. and a control means for loading said one pair of wheels on the basis of the detection information from the means actuating the the safety device when it is detected that is less than a predetermined load, said control means,該荷heavy rate of change substantially 0 Has dropped to
When it is detected, the predetermined change rate is set in advance.
The smallest initial predetermined change speed among the predetermined change speeds of the number
The initial change speed is set as the predetermined load.
A vehicle rollover prevention device characterized in that it is configured to set an initial set load corresponding to the degree . 2. A load detecting hand for detecting the load on the left and right wheels.
And the load change speed detection for detecting the load change speed of the left and right wheels.
Output means, a safety device for taking safety measures to prevent rollover of the vehicle, and the left side based on the detection information from the load change speed detection means.
The rate of change of load on either of the right wheels decreases
When it is detected that the predetermined change speed in the direction
On the basis of the detection information from the load detecting means,
When it is detected that the load of the wheel is less than a predetermined load,
A control means for operating the safety device, wherein the control means has a plurality of combinations of the predetermined changing speed and the predetermined load, and the first changing speed and the first changing speed are respectively the predetermined changing speed and the predetermined load. When a load is set, the load change speed of the one of the left and right wheels is equal to or higher than a first change speed in the decreasing direction of the load, and the load of the one wheel is larger than the first load. Is detected, a second change speed that is faster than the first change speed is set as the predetermined change speed, and the first load is set as the predetermined load as the predetermined load.
A vehicle overturning prevention device , characterized in that a second load that is even greater is set. 3. The control means, when it is detected that the load change speed is reduced to substantially 0, the control means sets the smallest initial predetermined change speed among a plurality of predetermined change speeds provided in advance as the predetermined change speed. 3. The vehicle rollover prevention device according to claim 2, wherein the vehicle rollover prevention device is configured to be set and an initially set load corresponding to the initial predetermined change speed is set as the predetermined load.