JPH04314649A - Collision safety device actuating circuit - Google Patents

Abstract

PURPOSE:To prevent a system total unit from being influenced, even when a trouble is generated partly in a plurality of judged parts, by separating a judged part, diagnosed generating a trouble, from the other normal judged part, and changing a circuit by a circuit changing means so that an OR-signal of an AND-signal of the normal judged part and a signal of the trouble judged part is used to serve as an action signal to a safety device. CONSTITUTION:A collision safety device is actuated based on an AND-signal of a signal whether collision is provided or not in a plurality of judged parts 2, 3 for judging the collision by a different method based on detection acceleration from an on-vehicle acceleration sensor 1. Here are provided a diagnostic means 6 for individually diagnosing a trouble of no-generation mode in the judged parts 2, 3 and a circuit changing means 4 for separating partly a judged part, diagnosed generating a trouble by the diagnostic means 6, from the other normal judged part changed into circuit constitution where an OR-signal of an AND-signal of the normal judged part and a signal of the trouble judged part is used as an action signal to the safety device.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for operating a safety device such as an air bag for protecting occupants in the event of a vehicle collision.

0002

[Prior Art] In order to detect a vehicle collision, there is usually a method of installing an acceleration sensor and making a judgment based on the level of detected acceleration. Even in this case, the detected acceleration may momentarily exceed a predetermined level.

[0003]Therefore, there is a method of integrating acceleration and converting it into velocity, and determining that a collision has occurred when the integrated velocity exceeds a preset level within a certain period of time. Another method is to make a determination based on a value obtained by further integrating the velocity obtained by integrating the acceleration. Furthermore, certain frequency ranges (e.g. 10
There is a method of determining a collision when the level of acceleration at a frequency of 0 to 200 Hz exceeds a certain value.

As described above, a collision can be determined using different methods based on acceleration, and it is also being considered to combine these various collision determination methods to ultimately determine a collision. By combining various determination methods in this manner, it is possible to improve the accuracy of collision detection.

[0005]

[Problem to be solved] However, when combining various judgment methods, it is a system based on logical product that activates the safety device only when all the judgment methods judge that there is a collision.
If even one of the determination units malfunctions in the non-explosion mode, it will affect the entire system and the safety devices will not operate in the event of a collision. Here, the non-explosion mode failure of the determination unit refers to a failure in which a signal indicating a collision is not outputted despite the acceleration being at a collision level.

[0006] Furthermore, if the system is based on a logical sum that activates a safety device when one of the various judgment units determines that there is a failure, the safety device will be erroneously activated if even one of the various determination units has a failure in an explosive mode. Here, the failure of the determination unit in the explosive mode refers to a failure in which the determination unit determines that there is a collision even though it is not a collision, and outputs a signal accordingly.

[0007] The present invention has been made in view of the above points, and an object thereof is to provide a collision safety device operating circuit that does not affect the entire system even if some of the plurality of determination units fail. At the point.

[0008]

[Means for Solving the Problems and Effects] In order to achieve the above object, the present invention has a plurality of determination units that determine a collision by different methods based on acceleration detected from an acceleration sensor mounted on a vehicle. In a collision safety system activation circuit that operates a collision safety system based on an AND signal of collision presence/absence signals of each determination unit, a diagnostic means for individually diagnosing a failure mode in a misfire mode of the plurality of determination units; A circuit that separates a part of the judgment section diagnosed as a failure from other normal judgment sections and uses the OR signal of the AND signal of the normal judgment section and the signal of the failure judgment section as an activation signal to the safety device. The collision safety device operating circuit is equipped with circuit changing means for changing the configuration.

[0009] When some of the judgment sections fail in the non-fire mode, the diagnostic means detects the failure and uses the OR signal of the AND signal of the other normal judgment sections and the signal of the failure judgment section as the activation signal of the safety device. However, the failure determination section does not affect the entire system, and the operation of the safety device is ensured by the judgment of other normal determination sections.

[0010] The vehicle also has a plurality of determination units that determine a collision using different methods based on the detected acceleration from the acceleration sensor mounted on the vehicle, and the collision safety system is activated based on the OR signal of the collision presence/absence signals of each determination unit. The collision safety device operating circuit to be activated includes a diagnostic means for individually diagnosing a failure in the explosion mode of the plurality of determination units, and a circuit change means for cutting off the output of the determination unit diagnosed as a failure by the diagnosis unit. By using a collision safety device activation circuit that is characterized by the Judgment ensures the operation of safety devices.

[0011]

[Embodiment] An embodiment of the present invention will be described below based on FIG. FIG. 1 is a simplified block diagram of this embodiment.

Electronic acceleration sensor 1 made of semiconductor etc.
A detection signal from the detector is input to the determining section A2 and the determining section B3. The determining units A2 and B3 determine a collision using different methods based on the detected acceleration. That is, in this embodiment, the determining section A2 is a circuit that compares the detected acceleration with a preset acceleration, and the determining section B3 is composed of an integrating circuit that integrates the detected acceleration and a comparing circuit that compares the integration result with a predetermined value.

The output signals of the determining sections A2 and B3 are input to the circuit changing section 4, and the circuit changing section 4 outputs an actuation signal to the safety device actuating section 5.

On the other hand, a diagnostic section 6 is provided for diagnosing failures in the non-fire mode of each of the determining sections A2 and B3, and the diagnostic results of the diagnostic section 6 are outputted to the circuit changing section 4 and used as a signal for changing the circuit. Failures in the non-fire mode include those caused by disconnections, and the diagnostic section 6 is comprised of these diagnostic circuits.

As an example of the circuit changing section 4, as shown in FIG. 2, an AND circuit 10 and an OR circuit 11 are provided in parallel. It is connected to one input terminal of each of the circuit 11, and the output terminal of the determination section B3 is also connected to one input terminal of each of the AND circuit 10 and the OR circuit 11 via the changeover switch 13.

Normally, the changeover switches 12 and 13 are connected to the AND circuit 10 side, and the output signals of the judgment section A2 and judgment section B3 are ANDed by the AND circuit 10 and output as an activation signal to the safety device activation section 5. be done. Therefore, the safety device activation unit 5 outputs an activation signal only when both the determination unit A2 and the determination unit B3 determine that there is a collision.

[0017] Here, if either the judgment unit A2 or the judgment unit B3 causes a failure in the non-fire mode, for example, if the judgment unit B3 causes a failure in the failure mode, the diagnosis unit 6 diagnoses this failure and changes the circuit. A change signal is output to section 4, the connection of changeover switches 12 and 13 is changed, and judgment section A2 and judgment section B are connected.
The signal No. 3 is output to the OR circuit 11, and the logical sum signal becomes the activation signal. Therefore, if the normal determining section A2 determines that there is a failure, an activation signal is output to the safety device activation section 5, allowing the safety device to operate.

It should be noted that when the judgment section A2 has a malfunction in the non-explosion mode, the safety device is activated only by the judgment section B3.

In this manner, even if there is a malfunction in the non-fire mode of the determining section A2 or B3, it does not affect the entire system, and other normal determining sections can be utilized.

[0020] In this embodiment, there are two determining units, but there are three determining units.
Even in the case of more than 1, the effect of the failure can be minimized by isolating the faulty judgment section and changing the circuit so that the AND signal of the other normal judgment section and the signal of the failure judgment section are ORed. Can be done.

Next, another embodiment will be explained based on FIG. 3. The detection signal of the acceleration sensor 21 is input to a determining section A22 and a determining section A23, and a collision is determined using different methods. The output signals of the determination units A22 and B23 are inputted to the input terminal of an OR circuit 26 via switches 24 and 25. The output terminal of the OR circuit 26 is connected to the input terminal of the safety device operating section 27.

On the other hand, a diagnostic section 28 is provided for diagnosing failures in the outburst mode of each of the determining sections A22 and B23, and the switches 24 and 25 are operated according to the diagnosis results of the diagnostic section 28. An explosive mode failure refers to a failure that outputs a signal that is determined to be abnormal even though there is no abnormality, and the diagnostic section 28 includes a circuit that detects this.

[0023] When the judgment parts A22 and B23 are normal and normal, the switches 24 and 25 are on and the judgment part A2 is in the on state.
2. The output signal of B23 is logically summed by the OR circuit 26 and outputted to the safety device actuator 27 as an actuation signal. Therefore, the system is such that an activation signal is output to the safety device activation unit 27 when either or both of the determination units A22 and B23 determine that a collision has occurred.

Here, if either the determining unit A22 or the determining unit B23, for example, the determining unit B23, has a failure in an explosive mode, the diagnostic unit 28 diagnoses this failure and switches the switch 25.
is activated to turn off the switch 25 and cut off the output of the determining section B23. Therefore, the safety device activation section 27 is activated based on the judgment of only the normal judgment section A22, and a failure of the judgment section B23 does not affect the entire system.

On the other hand, when the judgment section A22 has a failure in the explosive mode, the safety device is activated based on the judgment of the judgment section B23.

Furthermore, even if there are three or more determining units, if the output of only the failed determining unit is controlled to be cut off, the influence of the failure can be minimized by making use of other normal determining units.

[0027]

[Effects of the Invention] According to the present invention, the diagnosis section diagnoses failures in a plurality of judgment sections, and if one of them is faulty, the circuit is changed to utilize the judgments of the normal judgment sections to minimize the effects of the failure. It can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a simplified block diagram of one embodiment of the present invention.

FIG. 2 is a circuit diagram showing an example of a circuit changing section of the same example.

FIG. 3 is a simplified block diagram of another embodiment.

[Explanation of symbols]

1... Acceleration sensor, 2... Judgment part A, 3... Judgment part B, 4...
Circuit changing section, 5...Safety device operating section, 6...Diagnosis section, 10...
AND circuit, 11...OR circuit, 12, 13...changeover switch, 21...acceleration sensor, 22...judgment section A, 23...judgment section B, 24, 25...switch, 26...OR circuit, 27...
Safety device operating section, 28...Diagnosis section.

Claims (2)

[Claims] 1. A collision safety system comprising a plurality of determination units that determine a collision by different methods based on acceleration detected by an acceleration sensor mounted on a vehicle, and based on an AND signal of collision presence/absence signals of each determination unit. In the collision safety device operating circuit that operates the collision safety device, there is a diagnostic means for individually diagnosing failure in the non-fire mode of the plurality of judgment parts, and a part of the judgment parts diagnosed as failure by the diagnosis means is connected to other normal judgment parts. A collision safety device characterized by comprising a circuit changing means for changing the circuit configuration to a circuit configuration in which an AND signal of a normal judgment section and a signal of a failure judgment section is used as an activation signal to the safety device. operating circuit. 2. A collision safety device comprising a plurality of determination units that determine a collision using different methods based on acceleration detected by an acceleration sensor mounted on the vehicle, and based on a logical sum signal of collision presence/absence signals of each determination unit. A collision safety device operating circuit for activating a collision safety device includes a diagnostic means for individually diagnosing a failure in an explosion mode of the plurality of determination units, and a circuit change means for cutting off the output of a determination unit diagnosed as a failure by the diagnosis unit. A collision safety device activation circuit characterized by comprising: