JP2835982B2 - Operation control method of vehicle safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the operation of a vehicle safety device such as an air bag device or a seat belt restraining device for protecting an occupant from a collision shock in a vehicle collision. It relates to a method for controlling.

2. Description of the Related Art In order to operate a vehicle safety device in the event of a vehicle collision, conventionally, an electric output signal from an acceleration sensor provided in a vehicle is reduced by a certain amount corresponding to an acceleration allowable to an occupant. A method is known in which, when the integrated output exceeds a predetermined threshold value, it is determined that the vehicle has collided and a required safety device is activated (Japanese Patent Laid-Open No. 49-55).
No. 031). Therefore, according to this conventional method, by setting the threshold value to a value specific to the vehicle,
It can be determined whether the vehicle has collided.

(Problems to be Solved by the Invention) However, there are various modes of collision of the vehicle, and the impact generated on the vehicle body, that is, the change pattern of the deceleration of the vehicle body varies depending on the collision mode.

For example, when the vehicle collides head-on against a hard wall surface, a large negative acceleration occurs in the vehicle simultaneously with the collision, and the integral value decreases linearly with the speed. On the other hand, when the vehicle collides with the pole, a large acceleration is temporarily generated at the time of the collision, but the magnitude of the acceleration does not increase so much later, and the acceleration rapidly increases after a while. Become. That is, in the pole collision, there is a time when the integration does not progress very much after the integration has progressed to some extent at first, and then the integration tends to proceed greatly. This is because when the vehicle collides with an obstacle such as a pole, the contact portion is small, so that a slightly large deceleration occurs initially. After this, the soft parts (bumper, radiator, body, etc.) of the car body are deformed according to the shape of the pole, so there is no large deceleration. After this deformation, the pole hits the engine block, Deceleration occurs. In the case of an eccentric collision, the same course is followed.

Note that, when the track is recessed into the rear part, the above tendency becomes more remarkable depending on conditions. This is due to the fact that an obstacle does not easily hit a solid part of the vehicle body after being sunk.

Therefore, according to the conventional method in which the trigger signal is issued when the integration has greatly advanced, there is no problem in the case of a head-on collision, but in the case of a pole collision or the like, an airbag or the like is operated for, for example, 30 (ms) after the collision. ) When the vehicle is fully deployed later, the vehicle is greatly decelerated during the period of 30 ms, so that the displacement of the occupant becomes large in front of the occupant, and the occupant cannot be protected.

Also, in this case, if the threshold level is lowered to respond to the increase in the acceleration that occurs at the beginning of a pole collision, the vehicle responds to the increase in the acceleration of the vehicle caused by a cause other than the collision, resulting in malfunction. And the reliability of the collision detection operation is reduced.

As described above, in the conventional method, it is extremely difficult to properly detect the collision of the vehicle with respect to various impacts and collisions and to operate the vehicle safety device at an appropriate timing.

It is therefore an object of the present invention to provide a vehicle which can detect a collision of a vehicle early and operate the safety device at an appropriate timing without loss of reliability, regardless of the type of collision. It is an object of the present invention to provide a method for controlling the operation of a safety device for vehicles.

(Means for Solving the Problems) According to a method of the present invention for solving the above problems, a process of integrating an output signal from an acceleration sensor is started based on occurrence of a predetermined condition, and a vehicle obtained as a result of the integration process is obtained. In a control method in which the vehicle safety device is activated when the absolute value of the speed value exceeds the first level, a second level smaller than the first level is set, and a predetermined level is set from the start of the integration processing. If the absolute value of the vehicle speed value exceeds the second level before the time elapses, the integration constant for the integration process is increased for a predetermined time thereafter. .

(Operation) When a predetermined condition such as an acceleration value indicated by an output signal output from the acceleration sensor exceeding a predetermined value is satisfied, integration processing for the output signal is started. The absolute value of the integration obtained by the integration process is compared with the second level. If the absolute value of the integration exceeds the second level by a predetermined time after the start of the integration process, the integration is continued for a predetermined time thereafter. Increase the integration constant for processing.
As a result, during this predetermined time, the rate of increase of the value of the integrated output becomes larger than the rate of increase of the value of the integrated output before that time, so that a large integrated output can be obtained even with a small output signal. Is done.

Therefore, the time required for the integrated output to exceed the first level is reduced, and based on the single fact that the integrated output has exceeded the first level, or by adding an appropriate condition in addition to this fact. Thus, the occurrence of a vehicle collision can be determined earlier.

On the other hand, even if the value of the integration constant is changed so as to increase the rate of increase of the integral output and the incremental integration is performed, no collision of the vehicle occurs and the level increase of the output signal from the acceleration sensor is caused by another increase. If the cause is the cause, the integrated output does not reach the first level within the predetermined time, and thus the operation of the safety device is not started.

In the case of a pole collision, the period during which the progress of integration is small depends on the vehicle body and the collision speed, and it is dangerous to unnecessarily lengthen the period of increasing the integration constant to increase the integration. It is desirable to determine the period of the incremental integration with reference to the following. In the case of a hammer impact in the case of repair, etc., a large acceleration is temporarily generated, and even if the integration progresses, the acceleration is oscillating. Does not occur. Even after a temporary deceleration in a deer collision, a jumping over, a dent, etc., this deceleration ends rapidly, so that even if the processing of the incremental integration is performed, the integration does not proceed and no malfunction occurs.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a control device 2 for controlling the operation of an airbag device 1 which is a vehicle safety device according to the method of the present invention. The control device 2 is an airbag device 1
Is provided with an acceleration sensor 3 for detecting the acceleration of a vehicle (not shown) provided with the vehicle. The acceleration sensor 3 has a known configuration, and is attached to an appropriate portion of the vehicle, and an acceleration signal indicating an acceleration generated in the vehicle.
AS is output. The acceleration signal AS is amplified by an amplifier 4 and then input to an analog-to-digital (A / D) converter 5 where it is digitized and input to a microcomputer 6 as acceleration data AD.

The microcomputer 6 includes an input / output device (I / O) 7,
Central processing unit (CPU) 8, random access memory (RA
M) 9, a read-only memory (ROM) 10 and a known configuration comprising a bus 11 for interconnecting them.
The acceleration data AD is processed in accordance with the method of the present invention based on the control program stored in the control program 0, and when the result of the processing indicates that the vehicle has collided, the start signal is output.
KS is output.

The start signal KS is input to the drive circuit 12, whereby an ignition current is supplied to a squib 13 connected to the output thereof, which is an ignition actuator of the airbag device 1, and the gas generated at this time causes the airbag device 1 to be deployed. It is a configuration to do.

Next, a control program stored in the ROM 10 will be described with reference to FIGS.

FIG. 2 is a flowchart showing the main control program 20, and the execution is started at the same time when the power of the control device 2 is turned on. After initialization is executed in step 21, the acceleration data AD is read in step 22, and the flag F is read in steps 23 and 24.
Determination of whether or not A and FB are set is executed respectively. When the flag FA is set or when the flag FB is set, step 25 is executed, the activation signal KS is output, and the process returns to step 22. Note that each flag F
A and FB will be described later.

FIG. 3 is a flowchart of the interrupt 1 program 30 executed by interruption every predetermined time. Interrupt 1
When the program 30 is started, in a step 31, it is determined whether or not a flag F1 indicating that integration processing of the acceleration data AD for collision evaluation has been started is set. Immediately after initialization, F1 = "0",
The determination result in step 31 is NO, and in step 32, the integration value IA (negative value) obtained as a result of the normal integration performed based on the acceleration data AD becomes the start level LS (negative value).
Is compared with the size. Here, the vehicle suddenly decelerates at the time of a collision, and the acceleration at that time becomes a negative value, indicating the integrated value. In order to start the integration process for collision evaluation when IA <LS, in step 32, IA <LS
In the case of LS, the process proceeds to step 33, where the flag F1 is set, and in step 34, the clock operation of the first timer T1 is started.

Thereafter, the process proceeds to step 35 where the acceleration data
A normal integration process based on AD is executed, and the process proceeds to step 36. If IA ≧ LS in step 32, step 3
Steps 3 and 34 are not executed, and step 35 is entered directly.

In step 36, the integrated value IA obtained as a result of the normal integration process
Is smaller than a predetermined one level L1 (<LS). If IA ≧ L1, the decision result in the step 36 is NO, and the execution of this program ends. On the other hand, if IA <L1, the routine proceeds to step 37, where the first trigger flag FA is set to "1". Therefore, in this case, when the main control program 20 is executed, the determination result of step 23 becomes YES, and the squib 13 is ignited.

If the decision result in the step 31 is YES, a step 38
Then, it is determined whether or not IA = 0. IA ≠
If it is 0, the process proceeds to step 35, but if IA = 0, the flag F1 is cleared in step 39 and the first
After the timer T1 is reset, the execution of this program ends.

Next, the normal integration process executed in step 35 of the interrupt 1 program 30 will be described with reference to the flowchart of FIG. Upon entering the normal integration processing operation, step 41
Then, based on the value a of the acceleration signal AS, | a | ≧ α (where α
Is a constant), and if | a | ≧ α, the value of IA + a is replaced with IA in step 42, and the normal integration process ends. If | a | <α in step 41, the process proceeds to step 43, where it is determined whether or not IA ≧ 0. If IA is zero or positive, the process proceeds to step 44, where the value of IA-β is replaced by IA, and the normal integration process ends. On the other hand, if IA is negative, the value of IA + β is replaced with IA in step 45, thereby ending the normal integration process. That is, when the absolute value of the detected acceleration value is smaller than α, the value of IA is returned toward zero.

As can be seen from FIGS. 3 and 4, when the value IA obtained as a result of the normal integration process becomes smaller than LS, the collision evaluation is started, and when the condition IA <L1 is obtained, it is determined that the vehicle has collided. Then, the first trigger flag FA is set.

FIG. 5 shows a flowchart of the interrupt 2 program 50 executed by interruption every predetermined time. The interrupt 2 program 50 is a program for executing an incremental integration process using an integration constant larger than the integration constant used in the normal integration process 35 under a predetermined condition to determine a vehicle collision. is there.

When the execution of the interrupt 2 program 50 is started, first, at step 51, is a flag F2 indicating that the integration process of the acceleration data AD for evaluating the collision of the vehicle has been started by this program set? It is determined whether or not it is.

Immediately after initialization, F2 = "0" and the step
The determination result at 51 is NO, and at step 52, the integration value IB (negative value) obtained as a result of the integration processing performed according to the program 50 based on the acceleration data AD is changed to the start level LS
(Negative and value). When IB <LS, to start the integration process for collision evaluation,
If IB <LS, the process proceeds to step 53, where the flag F2 is set, and in step 54, the clock operation of the second timer T2 is started.

Thereafter, at step 55, it is determined whether or not a flag F3 indicating whether or not to perform the incremental integration process is set. Immediately after the initialization, F3 = "0", and therefore, the process proceeds to step 56, where it is determined whether or not IB <L2. L2 is
The second level is set to be smaller than the start level LS but larger than the first level L1, and is used as a reference level for determining whether or not to perform the incremental integration. If IB <L2, step 57 is entered where the second
The value of the timer T2 is whether a predetermined time t ₀ less is determined. T2
Flag F3 in step Step 58 If it is ≦ t ₀ is set, the normal integral operation is performed in step 59. This normal integration processing is the same processing as the processing shown in FIG. 4, and its integrated value is indicated here by IB, and is distinguished from the integrated value IA obtained by the interrupt 1 program 30.

Next, at step 60, it is determined whether or not the integrated value IB is smaller than the first level L1. If IB ≧ L1, the decision result in the step 60 is NO, and the execution of this program ends. On the other hand, if IB <L1, the routine proceeds to step 61, where the second trigger flag FB is set to “1”.

Therefore, in this case, when the main control program 20 is executed, the determination result of step 24 becomes YES, and the squib 13 is ignited.

If the decision result in the step 51 is YES, a step 62 is executed.
Then, it is determined whether or not IB = 0. IB ≠
If the value is 0, the process proceeds to step 55. If the value IB is 0, the flags F2 and F3 are cleared in steps 63 and 64, respectively, and the second timer T2 is reset in step 65. Ends.

Next, the case where F3 = "1" in step 55 will be described. In this case, go to step 66, where t ₁ = T2
Whether it is determined, in the case of t _1> T2 proceeds to step 59.
If t ₁ ≦ T2, step 67 is entered, where t ₁ ≦ T2 (>
t ₁ ) is determined.

If the decision result in the step 67 is YES, that is, if t ₁ ≦ T2 ≦ t ₂ , the incremental integration process is executed in a step 68, and the process proceeds to a step 60. On the other hand, if in step 67 with T2> t _2, enters step 69, where _{T2> t 3 (> t 2} ) whether it is determined, enters step 59 if T2 ≦ t _3, the normal integral Return to execution of processing. If it is step 69 in T2> t _3, the integrated value IB is zero at step 70, after the flag F2, F3 are people cleared respectively at step 71, returns to the main control blog ram 20.

That is, according to the interrupt 2 program 50, the IB <LS and turned to crash evaluation is started, the integral value flag F3 is set to After and time t ₀ has elapsed at the second level L2 or less incremental integration It is possible. And time t ₁ (> t ₀ )
Until subsequent t ₂ is the incremental integration process is performed in step 68.

The details of the incremental integration process are shown in FIG.
When entering the incremental integration processing operation according to FIG.
| a | ≧ α is determined, and if | a | ≧ α,
At 74, the value of a is converted to a larger predetermined value a1 according to the map data.

The characteristic for this conversion is, for example, as shown by a characteristic line (a) in FIG.
May be defined as a constant larger than 1), may be determined by a quadratic function as shown by a characteristic line (b), or may be a characteristic according to a required broken line characteristic as shown by a characteristic line (c) It may be.

Returning to FIG. 6, after the conversion process in step 73, the process proceeds to step 75, where the value of IB + a1 is replaced by IB,
The incremental integration processing using the value a1 larger than a ends.
If | a | <α in step 73, the process proceeds to step 76, where it is determined whether or not IB ≧ 0. If IB is zero or positive, step 77 is entered where the value of IB-β is replaced by IB, and the incremental integration process ends. On the other hand, if IB is negative, the value of IB + β is replaced with IB in step 78, thereby ending the incremental integration process. in this way,
In the incremental integration processing, the amount of increase in the integral value per step is larger than that in the normal integration processing, and the result is the same as that obtained by performing the integration calculation by increasing the integration constant.

When the T2> t _2, the integration process is returned again to the normal integration process, integrated value IB at the time point when T2 = t ₃ it is zero.
If IB> L1 during the above calculation, it is determined that the vehicle has collided, the second trigger flag FB is set, and the squib 13 is ignited by executing the main control program 20.

Next, the operation of the control device 2 shown in FIG. 1 when the vehicle collides with a pole will be described with reference to FIG.

In FIG. 8, the change in the integrated value IAI of the acceleration data AD in the case of the interrupt 1 program 30 is shown by a solid line, while the change in the integrated value IB of the same acceleration data AD by the interrupt 2 program 50 is shown by a dotted line. Have been.

When the vehicle collides with the pole and the vehicle starts to decelerate, the respective integral values IA and IB increase in the negative direction, and it is determined that t = 0 when the integral values IA and IB coincide with the start level LS. Interrupt 1 program 30
Then, the acceleration data AD is normally integrated, and after the collision evaluation starts, when the integrated value IA becomes smaller than the first level L1 at t = tb, the flag FA is set to “1”. In FIG. 8, the integration curve shown by the solid line, as previously described, but until t = t ₁ near the integral value is to some extent increase, not the integral value is then too large, the deformation of the body is finished At t = t ₂ , the pattern is a pattern in which the integral value increases greatly again. Therefore, the integral IA becomes equal to or lower than the first level L1 at t = tb after a considerable time has elapsed from the start of the collision.

On the other hand, until t = t ₁ when the incremental integration process is actually started, the value corresponding to the integration constant is a, so the integration value IB by the interrupt 2 program 50 is exactly the same as the value IA. But,
t = t ₁ hereinafter is greater al than the value a corresponding to the integration constant
To be converted to the integral value IB continues to drop with greater rate than t ₁ after integration value IA. As a result, the integral value IB increases in the negative direction, and the first value at the time ta earlier than the time tb.
Becomes lower than the level L1, where the second trigger flag FB
Is set to “1”.

As described above, due to the incremental integration, the pole collision is determined at the time ta earlier than the time tb, and the second trigger flag FB
The squib 13 can be ignited at the time when the value becomes "1".

Note that in steps 66 and 67 of the interrupt 2 program 50,
The values of t ₁ and t ₂ are determined optimally by, for example, a collision experiment according to the characteristics of the vehicle body of the vehicle on which the control device 2 is mounted. Can be detected. Since these values are changed by changing the program, no hardware change is required, and it is not necessary to prepare many types of hardware for matching for various vehicles, and in terms of cost. It is very advantageous.

In the above embodiment, after the collision evaluation start, but the integral value is configured to enter the incremental integration process if it becomes less than the second level L2 before the predetermined time t ₀ has elapsed, in this case, further, the acceleration A configuration may be adopted in which it is determined whether the acceleration value a indicated by the data AD is smaller than a predetermined level La, and when a ≦ La, the incremental integration process is performed only at a predetermined time.

In this case, for example, as shown in FIG. 9, the flowchart may be changed to FIG. That is, if the determination in step 55 is NO, it is determined in step 79 whether a ≦ La. If a ≦ La, the process proceeds to step 56. If a> La, steps 56 and 57 are performed. , 58, and proceed directly to step 59.

Further, in the above embodiment, each evaluation of the integrated value IA obtained according to the interrupt 1 program 30 and the integrated value IB obtained according to the interrupt 2 program 50 is performed using the same level L1. However, each evaluation for the integrated values IA and IB may be separately performed using different level values. For example, as shown in FIG. 10, step 60 in FIG. 5 is replaced by another level in which the value of IB is slightly smaller than level L1.
Step of determining whether or not L3 is smaller than L3 (see FIG. 8)
It may be configured to change to 60 '.

In this case, as can be seen from FIG. 8, when the integrated value IA becomes smaller than the level L1, or when the integrated value IB becomes lower than the level L3.
The ignition of the squib 13 is executed when at least one of the cases where the value becomes smaller is generated.

Further, the above configuration may be changed to a configuration in which ignition of squib 13 is performed only when integral value IA is smaller than level L1 and integral value IB is smaller than level L3 (<L1). In this case, in addition to the changes shown in Figure 10,
The main control program 20 shown in FIG. 2 may be changed as shown in FIG.

That is, in the main control program 20 'shown in FIG. 11, after inputting data in step 22, it is determined in step 23' whether or not FA = "1". Only when FA = "1", At step 24 ', it is determined whether or not FB = "1". If FB = "1", go to step 25,
Here, a process for outputting start signal KS is performed. As can be seen from FIG. 11, the first trigger flag FA
And only when both the second trigger flag FB is “1”,
A start signal KS is output.

As described above, in addition to the configuration of the first embodiment, at least the exemplary modifications are possible, and by selecting the above or other appropriate configuration according to the present invention according to the characteristics of the vehicle. Thus, control with more excellent characteristics can be realized.

(Effects of the Invention) According to the method of the present invention, as described above, the integral integration process is performed according to the state of the integrated value after the start of the collision evaluation, and the vehicle collision is determined in consideration of the result.
It is possible to easily cope with a change in the generation pattern of the acceleration depending on the manner of the vehicle collision, and to detect the vehicle collision faster and more reliably than the conventional method, and to cope with the collision. An excellent effect is achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a control device according to a control method of the present invention, FIG. 2 is a flowchart showing a main control program executed by the microcomputer of FIG. 1,
FIG. 3 is a flowchart showing an interrupt program executed along with the execution of the main control program, and FIG.
FIG. 5 is a detailed flowchart showing the normal integration process shown in the flowchart of FIG. 5, FIG. 5 is a flowchart showing another interrupt program executed in conjunction with the execution of the main control program, and FIG. 6 is a flowchart of FIG. FIG. 7 is a detailed flowchart showing the incremental integration processing shown in detail, FIG. 7 is a characteristic diagram showing an example of characteristics for conversion processing executed in the incremental integration processing according to FIG. 6, and FIG.
A graph for explaining the operation of the control device shown in the figure,
FIG. 9 and FIG. 10 are flowcharts each showing a modification unit for explaining a modification of the control device shown in FIG.
FIG. 11 is a flowchart showing a modification of the main control program of FIG. 1 ... airbag device, 2 ... control device, 3 ... acceleration sensor, 6 ... microcomputer, 13 ... squib, KS ... start signal, AS ... acceleration signal.

Claims (1)

(57) [Claims] An integration process of an output signal from an acceleration sensor is started based on the occurrence of a predetermined condition, and when the absolute value of the vehicle speed value obtained as a result of the integration process exceeds a first level, the vehicle safety is determined. In a control method for starting the device,
Setting a second level smaller than the first level,
When the absolute value of the vehicle speed value exceeds the second level before a predetermined time has elapsed from the start of the integration processing, the integration constant for the integration processing is increased for a predetermined time thereafter. An operation control method for a vehicle safety device, characterized in that: