JP2789569B2 - Control system for vehicle safety equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control system for a vehicle safety device.

2. Description of the Related Art As disclosed in JP-A-49-55031 and Japanese Utility Model Laid-Open No. 2-5371, a system for controlling a vehicle safety device such as an air bag is known. This control system includes an acceleration detecting means for detecting the deceleration of the vehicle, an integral calculating means for integrating the deceleration from the acceleration detecting means, and a presence / absence of a collision by comparing the integrated value from the integral calculating means with a threshold level. And a drive circuit for supplying an electric current to the squib of the airbag in response to the operation command signal from the collision determination means and inflating the airbag in response to the operation command signal from the collision determination means. And

[Problem to be Solved by the Invention] In the above control system, the time from the start of deceleration due to the vehicle collision to the completion of the expansion of the airbag is determined by the sum of the following first time and second time. The first time is the time from the start of deceleration to the time when the integrated value of the deceleration reaches the threshold level and the operation command signal for supplying current to the squib is output. The second time is a time from when the current starts flowing to the squib in response to the operation command signal until the inflation of the airbag is completed.

If the vehicle collides violently, in other words, if a sudden deceleration occurs in a short time, the time from the start of deceleration to the moment when the occupant is strongly pushed forward by the inertia force is short, so The airbag needs to be inflated. In the above control system, when the deceleration is large, the integrated value of the deceleration reaches the threshold level quickly, so that the first time can be shortened. However, since the second time is constant, the sum of the first time and the second time may not be sufficiently reduced. In order to eliminate this fear, it is required to lower the threshold level.

On the other hand, when the collision is gradual, in other words, when the deceleration occurs for a relatively long time, the occupant does not have a risk of colliding with the steering wheel or the like because the inertia force applied to the occupant is small. Therefore, in this case, it is necessary to prevent the airbag from inflating. However, although the deceleration is small, the integral value increases with the passage of time, so that the threshold level is reached and the airbag may malfunction. In order to eliminate this fear, the threshold level must be increased so that the integrated value does not easily reach the threshold level.

As is clear from the above description, although the threshold level is required to be low on the one hand and the threshold level is required to be high on the other hand, in the conventional control system, the threshold level is constant, so that both are required. It was not easy to satisfy.

[Means for Solving the Problems] The invention of claim 1 has been made to solve the above problems, and its gist lies in a control system for a vehicle safety device 1 shown in FIG. That is, the control system:
Acceleration detecting means 2 for detecting the deceleration of the vehicle, integration calculating means 3 for integrating the deceleration from the acceleration detecting means 2, and comparing the integrated value obtained by the integration calculating means 3 with a threshold level to determine whether there is a collision. And a collision judging means 4 for outputting an operation command signal when it is judged that there is a collision, and a vehicle safety device 1 based on the operation command signal from the collision judging means 4.
And a drive circuit 5 for operating the same. The control system further includes deceleration compensation means 6 for lowering the threshold level as the deceleration increases.

The gist of the invention of claim 2 is that, in addition to the configuration of the invention of claim 1, by changing the relationship between the threshold level and the deceleration corresponding to the vehicle speed from the vehicle speed detection means. And a vehicle speed compensating means for lowering the threshold level as the vehicle speed increases.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, a time measuring means for starting measurement of an elapsed time when the integral value reaches a predetermined level lower than the threshold level, and according to the elapsed time. A control system for a vehicle safety device, comprising: a time compensating means for changing a relationship between a threshold level and a deceleration.

[Operation] In the invention of claim 1, when the vehicle collides violently, in other words, when a sudden deceleration occurs in a short time, the threshold level is lowered according to the large deceleration.
The integrated value of the deceleration reaches the threshold level quickly, and the vehicle safety device operates quickly. Therefore, even if the time from the start of deceleration to the time when the occupant moves forward due to the inertial force is short, it is possible to make a sufficient time and secure the occupant's safety.

On the other hand, when the collision is gentle, in other words, when a small deceleration occurs over a relatively long time, the threshold level is increased. For this reason, even if the integral value of the deceleration increases with time, the threshold level is not easily reached, so that malfunction of the vehicle safety device can be prevented.

The invention of claim 2 takes into account the fact that there is a high possibility that a severe collision will occur when the vehicle speed is high, and that there is a high possibility that an instantaneous impact other than the collision or a relatively gentle collision will occur when the vehicle speed is low. is there. That is, by lowering the threshold level as the vehicle speed increases,
By obtaining a synergistic effect with the compensation by the acceleration, the vehicle safety device can be operated earlier in a severe collision, and the malfunction of the vehicle safety device can be more reliably prevented.

According to the third aspect of the present invention, when the integrated value of the deceleration value reaches a predetermined level, taking into account that the manner of change in deceleration due to an instantaneous impact other than a collision, a severe collision, or a relatively gentle collision is different. The relationship between the threshold level and the acceleration is changed depending on the elapsed time from the start. Thus, it is possible to accurately determine whether to operate the vehicle safety device in response to various impacts applied to the vehicle.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 schematically shows a control system for controlling the squib 1 of the airbag (vehicle safety device). The squib 1 is incorporated in the drive circuit 10. The drive circuit 10
It has a transistor 11 connected to one end of the squib 1 on the ground side. Between the squib 1 and the power supply, in order from the squib to the power supply, an energy reservoir (not shown) composed of a large-capacity capacitor and a booster circuit (not shown) for increasing the voltage of the energy reservoir higher than the power supply voltage. Is interposed.

The control system includes an acceleration sensing circuit 20 (acceleration detecting means) including an acceleration sensor. The acceleration sensing circuit 20 outputs a voltage signal corresponding to the acceleration of the vehicle. That is, a voltage that is lower than 2.5 V when the vehicle is accelerating and higher than 2.5 V when the vehicle is decelerated is output centering around 2.5 V.

The voltage signal of the acceleration sensing circuit 20 is
It is inverted and amplified by 30. More specifically, the inverting amplifier circuit 30 includes an operational amplifier 31, a variable resistor 32 connected in a negative feedback manner to the operational amplifier 31, and an input resistor 33. Operational amplifier 31
, A 2.5 V reference voltage Vr is input from an auxiliary constant voltage power supply 34 via a resistor 35. Therefore, the inverting amplifier circuit 30 outputs a voltage obtained by inverting and amplifying the voltage signal from the acceleration sensing circuit 20 around 2.5 V.
That is, the output voltage is higher than 2.5 V during acceleration and lower than 2.5 V during deceleration. By adjusting the gain with the variable resistor 32, an acceleration-output voltage characteristic equivalent to that using the reference acceleration sensor can be obtained.

The voltage from the inverting amplification circuit 30 is integrated by the integration circuit 40 (integration calculation means). The integrating circuit 40 includes a capacitor 42
The operational amplifier 41 is connected in a negative feedback manner, and input resistors 43 and 44 are connected to the inverting input terminal of the operational amplifier 41. The non-inverting input terminal of the operational amplifier 41
The offset voltage Vos is input. This offset voltage V
os is obtained by dividing the voltage of 2.5 V of the auxiliary constant voltage power supply 34 by the resistors 45 and 46, and is 2.0 V, for example.

In the integrator circuit 40, when a voltage lower than the offset voltage Vos (2.0V) is received from the inverting amplifier 30, the output voltage is increased by integrating this voltage, and when the output voltage is higher than the offset voltage Vos, the output voltage is increased. descend. In other words, when the deceleration of the vehicle is larger than the deceleration corresponding to the difference (0.5 V) between the reference voltage Vr and the offset voltage Vos, the output voltage increases and the integral calculation of the deceleration is performed. In addition, not only when the vehicle is accelerating, but also when the vehicle deceleration is 0.5V
When the deceleration is less than the deceleration, the output voltage of the integrating circuit 40 decreases.

The integration circuit 40 further includes a comparator 47.
The non-inverting input terminal of the comparator 47 receives the output voltage of the operational amplifier 41. The inverting input terminal of the comparator 47 receives the minute voltage 100 mV from the minute voltage power supply 48. When the voltage input from the inverting amplifier circuit 30 to the operational amplifier 41 is higher than the offset voltage Vos, the output of the operational amplifier 41 becomes zero volts.
It is maintained at 100mV without dropping. More specifically, when the output of the operational amplifier 41 falls slightly below 100 mV, the comparator 4
7 switches to low level, which causes operational amplifier 41
Output rises. When the output of the operational amplifier 41 slightly exceeds 100 mV, the comparator 47 switches to high impedance, and the output of the operational amplifier 41 decreases. As a result, the operational amplifier 41 is prevented from becoming saturated with the output voltage of zero V, and the output of the integration circuit 40 can always be maintained in the linear region.

The output of the integration circuit 40 is a comparator 50 (collision determination means)
Is input to the non-inverting input terminal. The threshold voltage from the threshold voltage generation circuit 60 (deceleration compensation means) is input to the inverting input terminal of the comparator 50. The threshold voltage generating circuit 60 is composed of a series circuit of resistors 61 and 62, one end of which is connected to the constant voltage circuit Vcc, and the other end of which is connected to the output stage of the inverting amplifier circuit 30. Then, the connection point voltage between the resistors 61 and 62 becomes the threshold voltage Vth
As provided to the comparator 50. This threshold voltage Vth can be expressed by the following equation.

Vth = (Vcc−Vg) · R ₆₂ / (R ₆₁ + R ₆₂ ) + Vg (1) As is clear from this equation, the threshold voltage Vth
Varies linearly with the voltage Vg representing the deceleration. That is, as indicated by the characteristic line in FIG. 3, the threshold voltage Vth decreases as the deceleration G increases.

Since the inverting amplifier 30 is a single power supply, even when the actual deceleration G is very large, the output voltage Vg
Does not become negative and its lower limit is zero volts. Therefore, the lower limit value Vth ₀ of the threshold voltage Vth is determined by substituting Vg = 0 into the above equation (1), and is expressed by the following equation.

Vth ₀ = Vcc · R ₆₂ / (R ₆₁ + R ₆₂ ) In the above configuration, the comparator 50 compares the output from the integration circuit 40 representing the integral value of the deceleration with the threshold level Vth, and the former exceeds the latter. At times, the output is turned high to turn on the transistor 11. Thereby, the squib 1 is ignited by receiving the current supply from the energy reservoir, and executes the expansion of the airbag.

As described above, since the threshold voltage Vth decreases as the deceleration increases, when the collision is severe and the deceleration is large, the integral output, which is the integral value of the deceleration, reaches the threshold voltage Vth quickly. , The ignition of the squib 1 can be executed. Thereby, the inflation of the airbag is accelerated, and the safety of the occupant can be ensured.

On the other hand, if the vehicle deceleration is small because the collision is so gentle that it is not necessary to inflate the airbag, the threshold voltage Vth will increase. Does not reach Vth. Thereby, malfunction of the airbag can be prevented. If the collision is not severe but the airbag needs to be inflated to protect the safety of the occupant, the integrated value of the deceleration is determined by the threshold voltage Vth
Takes a relatively long time to reach. However, in this case, there is no problem in ensuring the safety of the occupant since the time from the start of the collision until the occupant moves forward is relatively long.

Also, since the threshold level voltage Vth maintains a constant lower limit value Vth ₀ even when the deceleration increases, even if a very large deceleration occurs due to an instantaneous impact, the integrated voltage is lower than the lower limit of the threshold voltage. not reach the value Vth _0, it is possible to prevent an erroneous operation of the airbag from this point.

Although the above embodiment is a control system using an analog circuit, it is needless to say that the present invention can be applied to a control system using a microcomputer. The example of the control system described below uses all microcomputers. The microcomputer can perform not only the same control as in the above-described embodiment but also more precise control in consideration of the vehicle speed, the elapsed time at the time of impact, and the like.

The control system shown in FIG.
It has. In this figure, components corresponding to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. A voltage signal indicating acceleration is input from the acceleration sensing circuit 20 to an analog / digital converter 71 built in the microcomputer 70, and is converted into digital data. The microcomputer 70 has a vehicle speed sensor 72
(Vehicle speed detecting means), and a signal from the occupant switch 73 is input. The vehicle speed sensor 72 outputs a pulse as the axle rotates. The reciprocal of the number of pulses from the vehicle speed sensor 72 or the time interval of the pulses from the vehicle speed sensor 72 over a certain period of time indicates the vehicle speed. The occupant switch 73 is installed in each seat of the vehicle, and is turned on when a person sits. Therefore, the number of occupant switches turned on indicates the number of occupants. In the figure, a plurality of occupant switches are indicated by one block.

The microcomputer 70 has the maps A, B,
Use C. Each of the maps A, B, and C has a characteristic line similar to the threshold voltage-deceleration characteristic line in FIG. That is, the horizontal axis represents the deceleration G, and the vertical axis represents the threshold level Th. Also, as the deceleration G increases, the threshold level Th decreases.

The map A, B, in C, the threshold level Th in the region deceleration G is small is fixed at the upper limit value Th _1.
In a region where the deceleration G is intermediate, the threshold level Th has a substantially linear relationship with the deceleration G. In the deceleration G is larger region threshold level Th is constant at the lower limit value Th _2.

The maps A, B, and C are different from each other in the following points. Lower limit Th ₂ threshold level Th, the map A is the highest,
Map C is the lowest and map B is in between. Also, the slope of the characteristic line in the middle region of the deceleration G
Is the gentlest, map C is the steepest, and map B is in between. Therefore, if the decelerations G are equal,
The threshold level Th is higher in the order of the maps A, B, and C.

The microcomputer 70 selects the maps A, B, and C according to the vehicle speed, and determines the threshold level Th according to the deceleration based on the selected maps, as in the embodiment of FIG. The details will be described below.

The microcomputer 70 executes a timer interrupt routine shown in FIG. First, the acceleration sensing circuit
The deceleration G is obtained by multiplying the deceleration data from 20 by a constant gain (step 100). Since the acceleration sensing circuit 20 has an error with respect to the acceleration-output voltage characteristic of the reference acceleration sensing circuit, the gain is compensated by this gain.

Next, the deceleration G is integrated (step 101). That is, the deceleration G calculated this time is added to the integral value Δv stored in the RAM. Although not shown, when the deceleration G is equal to or less than a predetermined level or when the vehicle is accelerating, the integrated value Δ
Subtract a constant value from v. Then computes the vehicle speed v ₀ on the basis of a signal from the vehicle speed sensor 72 (step 102). Next, a constant a corresponding to the number of occupants is determined based on a signal from the occupant switch 73 (step 103). Although the constant a will be described later, the constant a is reduced as the number of occupants increases.

Next, it is determined whether or not a tire lock state occurs during sudden braking (step 104). Specifically, when the difference between the speed v 'determined in step 105 or 106 (described later) in the previous routine and the speed v ₀ calculated this time exceeds a predetermined value, it is determined that the tire is locked. Further, once it is determined that the tire is locked, it is determined that the tire is locked in step 104 of the routine that is executed within a certain period thereafter.

When the tires are locked, the vehicle speed obtained from the vehicle speed sensor rapidly decreases to zero, but the vehicle is in a slip state and gradually decelerates, but actually maintains a considerable vehicle speed.

When it is determined in step 104 that the tire lock has not occurred, the vehicle speed v ₀ calculated in step 102 is determined as the actual vehicle speed v (step 105). When it is determined that the tire is locked, the actual speed v is determined by subtracting the constant a determined in step 103 from the previously determined speed v '(step 106). In this way, the vehicle speed can be determined almost accurately.

Note that the larger the number of occupants, the greater the kinetic energy of the entire vehicle, and the slower the deceleration during a slip.
Considering this point, in step 103, the constant a is reduced as the number of occupants increases, so that the actual vehicle speed v can be calculated more accurately.

Next, it is determined whether or not the vehicle speed v determined as described above is lower than 10 km / h (step 107). If it is determined that it is lower than 10 km / h, select map A (step
108).

If a negative determination is made in step 107, the vehicle speed v is 20 km /
It is determined whether it is lower than h (step 109). If the determination is affirmative, that is, if it is determined that 10 km / h ≦ v <20 km / h, map B is selected (step 110). If it is determined that it is 20 km / h or more, map C is selected (step 11).
1).

Next, a threshold level Th corresponding to the acceleration is determined based on the selected map (step 11).
2) The integrated value Δv of the deceleration is equal to the threshold level T
It is determined whether or not h has been reached (step 113). If the determination is affirmative, the routine jumps to the collision control routine, in which a high-level operation command signal is output to the transistor 11 to ignite the squib 1. If a negative determination is made, the process returns to the main routine.

As described above, when the vehicle speed is high, the map C having a lower threshold level Th than the deceleration G is selected. When the vehicle speed is high, the impact at the time of the collision is likely to be large,
By selecting the map C, the airbag can be inflated more quickly.

When the vehicle speed is low, a map B having a higher threshold level Th than the deceleration G is selected. When the vehicle speed is low, there is a high possibility that the impact is relatively moderate.
By selecting, the malfunction of the airbag can be more reliably prevented.

When the vehicle speed is very low, a map A having a high threshold level Th in a region where the deceleration G is large is selected.
Thereby, particularly when a very large deceleration is instantaneously received like a hammer blow at the time of repair, malfunction of the airbag can be more reliably prevented.

As is clear from the above description, in the routine shown in FIG. 6, steps 107 to 111 substantially constitute vehicle speed compensating means, and step 112 constitutes deceleration compensating means.
Step 113 constitutes collision determination means.

The microcomputer may select the map based on the elapsed time at the time of the collision. In this case, the microcomputer executes the timer interrupt routine shown in FIG. In FIG. 7, steps corresponding to those in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted. In detail, after the integration operation in the step 101, the integral value Delta] v is determined whether a predetermined level Delta] v ₁ below (step 20
0). This predetermined level is much lower than the threshold level Th, and is the level of the deceleration integrated value achieved by a relatively small impact.

If the determination is affirmative, the flag Ft is reset (step 201), and the process returns to the main routine. This flag Ft
This indicates that a timer T (time measuring means) described later is measuring elapsed time.

If a negative decision is made in step 200, that is, when the integrated value Delta] v is determined to exceed the predetermined value Delta] v ₁ is
The vehicle is ready for collision determination. First, the flag Ft
Is set or not (step 20).
2). If not set, the flag Ft is set (step 203), the timer T is reset (step 204), and the timer T starts counting (step 2).
05), proceed to step 206. If it is determined in step 202 that the flag Ft has been set, steps 203 to 205
To step 206.

In step 206, the elapsed time measured by the timer T is determined whether the first less than the set time [Delta] T _1. If it is determined that the value is less than the predetermined value, the map A in FIG. 8 is selected (step 207).

When it is determined in step 206 that the elapsed time is equal to or longer than the first set time ΔT _1, it is determined whether the elapsed time measured by the timer T is shorter than the second set time ΔT ₂ (step 208). If the determination is affirmative, that is, if it is determined that the elapsed time T is ΔT ₁ ≦ T <ΔT ₂ , the map B in FIG. 8 is selected (step 209). In the case of a negative determination, that is, when T ≧ ΔT ₂ , the map C in FIG.
210).

8 are different from each other in the following points. Lower limit Th ₂ threshold level Th, the map C is the highest, the map B is the lowest, the map A is between.
The slope of the characteristic line in the middle region of the deceleration G is the gentlest in the map C, the steepest in the map B, and the steepest in the map A
Is in between. Therefore, when the decelerations G are equal, the threshold level Th is lower in the order of the maps B, A, and C, and the squib ignition is performed earlier in this order.

The utility of the above map selection will be described with reference to FIG. In FIG. 9, the upper side represents deceleration and the lower side represents acceleration.

The reason for selecting the map A at the beginning (T <ΔT ₁ ) is to prevent the airbag from malfunctioning when receiving the hammer blow shown in FIG. 9 (A). That is, the hammer blow gives a large deceleration to the vehicle but is instantaneous, and the impact disappears within ΔT ₁ from the start of the measurement. In this case, the lower limit value of the threshold level in the region of large deceleration G
By Th ₂ chooses a relatively high map A, the integral value does not reach the threshold level.

The reason for selecting the map B in the middle period (ΔT ₁ ≦ T <ΔT ₂ ) is that it is not necessary to consider that the impact of the vehicle is a hammer blow, and for example, a severe collision such as a frontal collision shown in FIG. 9 (B). This is because the airbag must be prepared for rapid inflation.

In the latter period (T ≧ ΔT ₂ ), even a collision is a gentle collision. However, even though the deceleration is relatively small, the integration value is at a high level due to integration over a long period of time. When an instantaneous impact, such as a secondary collision, with a high deceleration occurs thereafter, if the threshold level is lowered in response to a large deceleration, the integrated value may exceed the threshold level. Therefore, at this time, by selecting the map C and setting the threshold level higher, it is possible to more reliably prevent the malfunction of the airbag.

As is clear from the above description, in the routine of FIG. 7, steps 206 to 210 substantially constitute time compensating means.

In the microcomputer, instead of selecting the map in response to the vehicle speed or the elapsed time at the time of the collision, the scaling of the coordinate axes in one map may be substantially changed. That is, when determining the threshold level, the deceleration to be substituted into the map is obtained by adding or subtracting or multiplying the deceleration by a constant determined according to the vehicle speed or the elapsed time. Further, an integral value to be compared with the threshold level is obtained by adding or subtracting or multiplying a constant determined according to the vehicle speed or the elapsed time to the integral value of the deceleration.

Next, an embodiment will be described in which the deceleration to be substituted into the map and the integrated value to be compared with the threshold level are changed by changing the gain of the acceleration according to the elapsed time at the time of the collision. In this case, the microcomputer executes the timer interrupt routine shown in FIG. 10 using one map shown in FIG. In FIG. 10, steps corresponding to the routine of FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted. In this routine,
In step 300, a gain is calculated in accordance with the elapsed time T instead of selecting the map.

Referring to FIG. 12, before starting the measurement of the elapsed time to a relatively large value A ₁ of the gain. Lowering the gain at the measurement start time of the elapsed time to a small value A _2, by increasing gradually the gain due to the elapsed time, back to A _1. Elapsed time
When T ₀ is reached, the gain is reduced again to A ₂ .

If the gain is large, the deceleration G calculated in step 100 becomes larger than the actual deceleration. That is, the deceleration G substituted in the map of FIG. 11 increases, and the threshold level is determined to be low. Further, since the deceleration G increases, the integrated value calculated in step 101 also increases quickly. This is substantially equivalent to lowering the threshold level. As a result, the airbag operates quickly. The opposite is true for small gains.

To that the large value A ₁ of the gain before starting the measurement of the elapsed time, the integrated value Delta] v to reach quickly a predetermined level Delta] v ₁ described above, in order to hasten the measurement start of the elapsed time.

Was lowered gain A ₂ is a measurement start point of the elapsed time in order to cope with a hammer blow.

Thereafter, the gain was raised again to A ₁ is to prepare for rapid inflation of the airbag in mind violent collision.

The elapsed time is lowered again A ₂ the gain when it reached T ₀ is to more reliably prevent erroneous operation of the airbag in a gentle crash.

As is apparent from the above description, in the routine of FIG. 10, step 300 constitutes a time compensating means.

In the microcomputer, the threshold level corresponding to the deceleration may be calculated by an equation instead of the map.

In the present specification, lowering the threshold level according to the deceleration means, more strictly, lowering the absolute value of the threshold level. For example, in an embodiment where the deceleration appears as a negative value, the threshold level is also a negative value and moves toward zero as the deceleration increases.

The threshold level may be changed stepwise according to the deceleration. In an extreme example, two stages may be used.

The control system of the present invention is applicable not only to airbag control but also to seatbelt control.

[Effects of the Invention] As described above, according to the first aspect of the present invention, by changing the threshold level according to the deceleration,
When the collision is severe, the operation of the vehicle safety device can be accelerated to ensure the safety of the occupant, and the malfunction of the vehicle safety device can be reliably prevented.

According to the second aspect of the present invention, the relationship between the deceleration and the threshold level is changed according to the vehicle speed, so that the vehicle safety device can be operated more quickly when necessary, and the malfunction is more reliably prevented. be able to.

According to the third aspect of the present invention, the relationship between the deceleration and the threshold level is changed according to the elapsed time at the time of the collision, so that the more accurate and quicker the collision according to various impacts applied to the vehicle. The determination can be made, and the vehicle safety device can be operated more quickly and surely, and the malfunction can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention. FIG. 2 is a circuit diagram schematically showing one embodiment of the present invention, and FIG. 3 is a characteristic diagram of deceleration-threshold voltage obtained by the circuit of FIG. FIG. 4 is a circuit block diagram of another embodiment using a micro computer, FIG. 5 is a diagram showing a deceleration-threshold level map used in the micro computer of FIG. 4, and FIG. 6 is a diagram of FIG. 6 is a flowchart illustrating a timer interrupt routine executed by the microcomputer. FIG. 7 is a flowchart showing another embodiment of a timer interrupt routine executed by the microcomputer, FIG. 8 is a view showing a map used in the routine of FIG. 7, and FIG. 5 is a time chart showing the deceleration of FIG. FIG. 10 is a flowchart showing still another embodiment of the timer interrupt routine executed by the microcomputer, FIG. 11 is a diagram showing a map used in the routine of FIG. 10, and FIG. 12 is a time showing a change in gain. It is a chart. 1 ... vehicle safety device, 2,20 ... acceleration detecting means, 3,40 ...
… Integral calculation means, 4,50,113 …… Collision determination means, 5,10 ……
Driving circuit, 6, 60, 112 ... deceleration compensation means, 72 ... vehicle speed detection means, T ... time measurement means, 107-111 ... vehicle speed compensation means, 206-210, 300 ... time compensation means.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hideki Ishizuka 3-13-26, Yayumicho, Higashimatsuyama-shi, Saitama Pref. Inside the Higashimatsuyama Plant of Diesel Equipment Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) B60R 21/16-21/32 G01P 15/00

Claims (3)

(57) [Claims] A) an acceleration detecting means for detecting the deceleration of the vehicle; b) an integration operation means for integrating the deceleration from the acceleration detection means; c) a threshold level obtained by the integration operation means; Collision determination means for determining the presence or absence of a collision in comparison with the above, and outputting an operation command signal when the collision is determined; d) a drive circuit for operating the vehicle safety device based on the operation command signal from the collision determination means A control system for a vehicle safety device, further comprising deceleration compensation means for lowering the threshold level as the deceleration increases. . 2. A vehicle speed detecting means, and a vehicle speed compensating means for lowering the threshold level as the vehicle speed increases by changing the relationship between the threshold level and the deceleration in accordance with the vehicle speed from the vehicle speed detecting means. The control system for a vehicle safety device according to claim 1, comprising: 3. A time measuring means for starting measurement of an elapsed time when the integrated value reaches a predetermined level lower than the threshold level, and a time for changing a relation between the threshold level and the deceleration according to the elapsed time. The control system for a vehicle safety device according to claim 1, further comprising a compensation unit.