JP2009190701A - Vehicle overturn determination device and vehicle overturn protection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle overturn determination device stably determining occurrence of an accident having a long event duration while preventing an increase in a memory space required for signal processing applied to output signals of a sensor. <P>SOLUTION: Based on a value obtained by applying predetermined signal processing to output signals of an acceleration sensor installed in a predetermined portion of a vehicle to detect the acceleration, the vehicle overturn determination device determines occurrence of vehicle overturn. The vehicle overturn determination device is provided with a signal processing means to which the output signals of the acceleration sensor is inputted and which outputs a value obtained by applying the signal processing to the output signals of the acceleration sensor by using a smoothing procedure of time series data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

 The present invention relates to a vehicle rollover judging device and a vehicle rollover protection system.

Conventionally, an angular velocity sensor that detects the roll angular velocity of the vehicle, a Y-axis acceleration sensor that detects acceleration in the lateral direction of the vehicle (hereinafter referred to as the Y axis), and an acceleration in the vertical direction of the vehicle (hereinafter referred to as the Z axis). By installing a Z-axis acceleration sensor to be detected at a predetermined location of the vehicle, detecting the vehicle rollover based on the output signal of each sensor, and starting an occupant protection device such as a curtain airbag or a seat belt pretensioner An SRS (Supplemental Restraint System) airbag system that prevents an occupant from being released outside the vehicle is known (see, for example, Patent Documents 1 and 2 below).
JP 2005-335501 A JP 2007-137280 A

  In the SRS airbag system described above, an integral value (roll angle, speed change in the Y-axis direction, speed in the Z-axis direction) obtained by subjecting the output signals of the angular velocity sensor, the Y-axis acceleration sensor, and the Z-axis acceleration sensor to the interval integration process. It is common to determine whether or not a rollover has occurred in a vehicle based on (change). Such a rollover has a longer event duration compared to other accidents such as a frontal collision and a side collision, so the longer the integration time in the above-mentioned interval integration process, the more stable the rollover occurs. Can be determined. However, when the integration time is set long, there is a problem that a huge memory space is required for the interval integration processing.

    The present invention has been made in view of the above-described circumstances, and stably determines the occurrence of a rollover accident with a long event duration while preventing an increase in memory space required for signal processing applied to the output signal of the sensor. It is an object of the present invention to provide a vehicle rollover judging device that can be used, and a vehicle rollover protection system including the vehicle rollover judging device.

  In order to achieve the above object, the present invention provides, as a first solution means according to a vehicle rollover judging device, subjecting an output signal of an acceleration sensor installed at a predetermined location of a vehicle to predetermined signal processing. A vehicle rollover determination device for determining occurrence of vehicle rollover based on an obtained value, wherein the output signal of the acceleration sensor is input and signal processing is performed on the output signal of the acceleration sensor using a time-series data smoothing technique And a signal processing means for outputting a value obtained by applying.

    Further, as a second solving means relating to the vehicle rollover judging device, in the first solving means, the signal processing means uses an exponential smoothing average as a smoothing technique of the time series data. .

Further, as a third solving means relating to the vehicle rollover judging device, in the second solving means, the signal processing means includes an input signal X (n), an integration time constant α, a sampling frequency fs, an integration time t, and an output. Signal processing based on the exponential smoothing average is performed on the basis of the following equation (1) consisting of a value Y (n).
Y (n) = α · X (n) + (1−α) · Y (n−1) (1)
However, α = 2 / (1 + fs · t)

  Further, as means for solving the vehicle rollover protection system, an acceleration sensor for detecting acceleration installed at a predetermined location of the vehicle, a protection device for protecting a party of the vehicle rollover when the vehicle rollover occurs, and the acceleration sensor The vehicle rollover judging device having any one of the first to third solving means for judging the occurrence of vehicle rollover based on the output signal of the vehicle, and according to the judgment result of the occurrence of vehicle rollover by the vehicle rollover judging device And a protection activation device that activates the protection device.

  According to the vehicle rollover judging device according to the present invention, signal processing is performed on the output signal of the sensor using a time series data smoothing technique, so that the signal processing is compared with the conventional technique of performing the interval integration process. The necessary memory space may be low in capacity, and as a result, it is possible to stably determine the occurrence of an accident with a long event duration while preventing an increase in memory space.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a vehicle rollover protection system including a vehicle rollover judging device according to the present embodiment. In the present embodiment, the vehicle rollover protection system detects the rollover of the vehicle and deploys (starts up) the curtain airbag as the occupant protection device to prevent the occupant from being released outside the vehicle. (Supplemental Restraint System) An airbag system will be described as an example.

  As shown in FIG. 1, the SRS airbag system according to the present embodiment includes an SRS unit 10 installed near the center inside the vehicle 100, an angular velocity sensor 20 provided in the SRS unit 10, and a Y-axis acceleration sensor. 30, Z-axis acceleration sensor 40, rollover judging device (vehicle rollover judging device) 50, ignition devices 60R and 60L, curtain airbag 70R installed near the right side window inside vehicle 100, and installed near the left side window The curtain airbag 70L is generally configured.

  The SRS unit 10 controls the SRS airbag system in an integrated manner, detects the rollover of the vehicle 100 based on the output signals of the angular velocity sensor 20, the Y-axis acceleration sensor 30, and the Z-axis acceleration sensor 40, and curtains The airbags 70R and 70L are deployed. In addition to the rollover, the SRS unit 10 outputs output signals from front crash sensors installed on the left and right of the front portion of the vehicle 100 (not shown), side impact sensors installed on both sides of the vehicle 100, and the like. Based on this, it has a function of detecting that a frontal collision or a side collision has occurred and deploying a driver airbag, a passenger airbag, and a side airbag (not shown). Is omitted.

The angular velocity sensor 20 detects the roll angular velocity of the vehicle 100 and outputs a signal corresponding to the roll angular velocity to the rollover judging device 50. The Y-axis acceleration sensor 30 detects acceleration in the lateral direction (Y-axis) of the vehicle 100 and outputs a signal corresponding to the acceleration in the Y-axis direction to the rollover determination device 50. The Z-axis acceleration sensor 40 detects the acceleration in the vertical direction (Z-axis) of the vehicle 100 and outputs a signal corresponding to the acceleration in the Z-axis direction to the rollover determination device 50.
The angular velocity sensor 20, the Y-axis acceleration sensor 30, and the Z-axis acceleration sensor 40 are not necessarily provided inside the SRS unit 10, and may be provided outside in consideration of maintainability.

  The rollover determination device 50 receives output signals from the angular velocity sensor 20, the Y-axis acceleration sensor 30, and the Z-axis acceleration sensor 40, and determines whether rollover has occurred in the vehicle 100 based on the output signals from these sensors. In response to the determination result, a deployment instruction signal for instructing deployment of the curtain airbags 70R and 70L is output to the ignition devices 60R and 60L. Hereinafter, the detailed configuration of the rollover judging device 50 will be described with reference to FIG.

  FIG. 2 is a block configuration diagram of the rollover judging device 50. As shown in FIG. 2, the rollover judging device 50 includes a section integrating circuit 51, a rollover main judging circuit 52, a safing circuit 53, and AND circuits 54 and 55. The safing circuit 53 includes a first exponential smoothing average circuit (signal processing means) 53a, a second exponential smoothing average circuit (signal processing means) 53b, a first comparison circuit 53c, and a second comparison circuit. 53d and an OR circuit 53e.

  The interval integration circuit 51 receives the output signal of the angular velocity sensor 20 as input, performs interval integration processing of this output signal, and outputs an integrated value (roll angle dAng) obtained by the interval integration processing to the rollover main determination circuit 52. The rollover judging circuit 52 receives the output signal of the angular velocity sensor 20, the output signal of the Y-axis acceleration sensor 30, and the roll angle dAng output from the section integrating circuit 51, and inputs to the vehicle 100 based on these signals. It is determined whether or not rollover has occurred, and a deployment instruction signal for instructing deployment of the curtain airbags 70R and 70L is output to the AND circuits 54 and 55 according to the determination result. Specifically, the rollover main determination circuit 52 outputs a high level signal to the AND circuit 54 as a deployment instruction signal when the curtain airbag 70R is deployed, and as a deployment instruction signal when the curtain airbag 70L is deployed. A high level signal is output to the AND circuit 55.

  The safing circuit 53 is an auxiliary circuit provided so that the expansion control can be reliably performed by confirming with two or more circuits even when the angular velocity sensor 20 fails. The first exponential smoothing average circuit 53a in the safing circuit 53 receives the output signal of the Y-axis acceleration sensor 30 as an input, and applies a value dVy obtained by subjecting the output signal to exponential smoothing averaging processing. Output to the non-inverting input terminal of the comparator circuit 53c. The second exponential smoothing average circuit 53b receives the output signal of the Z-axis acceleration sensor 40 as an input, and a value dVz obtained by subjecting this output signal to exponential smoothing averaging processing is a non-inverting input of the second comparison circuit 53d. Output to the terminal.

  The first comparison circuit 53c is, for example, a comparator, compares dVy input to the non-inverting input terminal with a threshold value dVy-th input to the inverting input terminal, and outputs a signal corresponding to the comparison result to the OR circuit 53e. Output to. Specifically, the first comparison circuit 53c outputs a high level signal when dVy ≧ dVy−th. The second comparison circuit 53d is, for example, a comparator, compares dVz input to the non-inverting input terminal with a threshold value dVz-th input to the inverting input terminal, and outputs a signal corresponding to the comparison result to the OR circuit 53e. Output to. Specifically, the second comparison circuit 53d outputs a high level signal when dVz ≧ dVz−th. The OR circuit 53e outputs a logical sum signal of the output signal of the first comparison circuit 53c and the output signal of the second comparison circuit 53d to the AND circuits 54 and 55.

  The AND circuit 54 outputs a logical product signal of the output signal of the rollover main determination circuit 52 and the output signal of the OR circuit 53e to the ignition device 60R. The AND circuit 55 outputs a logical product signal of the output signal of the rollover main determination circuit 52 and the output signal of the OR circuit 53e to the ignition device 60L.

The above is the detailed description of the rollover judging device 50, and the description will be continued by returning to FIG.
The ignition device 60R receives the output signal of the AND circuit 54 as an input, and when the output signal is a high level signal, the ignition device 60R deploys the curtain airbag 70R by passing a current through the squib for the curtain airbag 70R and igniting it. The ignition device 60L receives the output signal of the AND circuit 55 as an input. When this output signal is a high level signal, the ignition device 60L deploys the curtain airbag 70L by causing a current to flow through the squib for the curtain airbag 70L and igniting it. The curtain airbags 70 </ b> R and 70 </ b> L are airbags provided as occupant protection devices, and are deployed when a rollover occurs to protect the occupant under the control of the SRS unit 30.

  Next, the operation of the SRS airbag system configured as described above (particularly, the rollover determination operation by the rollover determination device 50) will be described with reference to the flowchart of FIG.

  As shown in FIG. 3, the output signals of the angular velocity sensor 20, the Y-axis acceleration sensor 30, and the Z-axis acceleration sensor 40 are continuously input to the rollover judging device 50 after the power is turned on (ignition ON). The section integration circuit 51 outputs an integrated value (roll angle dAng) obtained by performing the section integration process on the output signal of the angular velocity sensor 20 to the rollover main determination circuit 52 (step S1).

On the other hand, the first exponential smoothing averaging circuit 53a outputs a value dVy obtained by subjecting the output signal of the Y-axis acceleration sensor 30 to exponential smoothing averaging processing to the non-inverting input terminal of the first comparison circuit 53c ( Step S2). Here, when the input signal (that is, the output signal of the Y-axis acceleration sensor 30) is G (n), the integration time constant is α, the sampling frequency is fs, and the integration time is t, the input signal G (n) is exponentially smoothed. The output value dVy (n) obtained by performing the averaging process can be expressed by the following equation (2).
dVy (n) = α · G (n) + (1−α) · dVy (n−1) (2)
However, α = 2 / (1 + fs · t)

  In this way, the output value (current value) of the exponential smoothing average process, dVy (n), is obtained by multiplying the current value G (n) of the input signal by the integration time constant α and the exponential smoothing average. It is obtained as an addition value with a value obtained by multiplying dVy (n−1), which is an output value (previous value) of processing, by (1−α). That is, the first exponential smoothing average circuit 53a performs G (n) which is the current value of the input signal and dVy (n−1) which is the previous value of the output value in order to perform exponential smoothing averaging processing. And the integration time constant α, which is a constant, is required, and the memory space required for the exponential smoothing averaging process is constant even when the integration time t is longer than that in the conventional interval integration process. In addition, a low capacity is sufficient.

  FIG. 4A shows the output value of the exponential smoothing average when the sine wave shown in FIG. 4B is used as an input signal, the sampling frequency is set to 1 kHz, and the integration time is set to 20, 100, 200, and 400 msec. This is a comparison of output values of interval integration. In FIG. 4 (a), since the sum of the intervals is the output value for the interval integration and the average value is the output value for the exponential smoothing average, the output value of the exponential smoothing average is set to facilitate comparison between the two. The integration time is multiplied so that the display is equivalent to the interval integration.

  As shown in FIG. 4A, it can be seen that even when the integration time is set to be long, the output value of the exponential smoothing average is almost the same as the output value of the interval integration. In other words, by using exponential smoothing averaging, even if the integration time is set to be long, it is possible to obtain an output value similar to that of interval integration while suppressing the memory capacity required for signal processing.

  FIG. 5 shows a comparison between the output value of the exponential smoothing average and the output value of the interval integral when the input signal assuming an actual event is used. FIG. 5A shows a case where a rough road is assumed, and FIG. 5B shows a case where a rollover is assumed. As shown in these figures, the output value of the exponential smoothing average and the output value of the interval integral have the same changing tendency when traveling on rough roads and rollovers occur. It can be seen that the occurrence of rollover can be determined without any problem as in the case of using interval integration.

  Hereinafter, returning to FIG. 3, the description will be continued. The second exponential smoothing averaging circuit 53b outputs a value dVz obtained by subjecting the output signal of the Z-axis acceleration sensor 40 to exponential smoothing averaging processing to the non-inverting input terminal of the second comparison circuit 53d (step S3). ).

  The rollover main determination circuit 52 determines whether or not a rollover has occurred in the vehicle 100 based on the output signal of the angular velocity sensor 20, the output signal of the Y-axis acceleration sensor 30, and the roll angle dAng output from the section integration circuit 51. When the curtain airbag 70R is deployed according to the determination result, a high level signal is output to the AND circuit 54, and when the curtain airbag 70L is deployed, a high level signal is output to the AND circuit 55. (Step S4).

  On the other hand, the first comparison circuit 53c compares the output value dVy of the first exponential smoothing averaging circuit 53a with the threshold value dVy-th (step S5), and when dVy ≧ dVy-th (“Yes”), A high level signal is output to the OR circuit 53e (step S6). If dVy <dVy−th (“No”), a low level signal is output to the OR circuit 53e (step S7).

  Further, the second comparison circuit 53d compares the output value dVz of the second exponential smoothing averaging circuit 53b with the threshold value dVz-th (step S8), and when dVz ≧ dVz-th (“Yes”), A high level signal is output to the OR circuit 53e (step S9). If dVz <dVz−th (“No”), a low level signal is output to the OR circuit 53e (step S10).

  The OR circuit 53e performs a logical OR process on the output signal of the first comparison circuit 53c and the output signal of the second comparison circuit 53d (step S11), and at least the first comparison circuit 53c and the second comparison circuit 53d. When one of the output signals is a high level signal ("Yes"), the high level signal is output to the AND circuits 54 and 55 (step S12), and the first comparison circuit 53c and the second comparison signal are output. When both output signals to the circuit 53d are low level signals ("No"), the low level signals are output to the AND circuits 54 and 55 (step S13).

  The AND circuit 54 performs an AND operation on the output signals of the rollover main determination circuit 52 and the OR circuit 53e (step S14), and the output signals of both the rollover main determination circuit 52 and the OR circuit 53e are high level signals. In the case (“Yes”), a high level signal (a signal for instructing the deployment of the curtain airbag 70R) is output to the ignition device 60R (step S15), and the rollover main determination circuit 52, the OR circuit 53e, and one output signal are output. Is a low level signal (“No”), the low level signal is output to the ignition device 60R (step S16).

  The AND circuit 55 performs a logical product process of the output signals of the rollover main determination circuit 52 and the OR circuit 53e (step S17), and the output signals of both the rollover main determination circuit 52 and the OR circuit 53e are high level signals. If there is (“Yes”), a high level signal (a signal for instructing deployment of the curtain airbag 70L) is output to the ignition device 60L (step S18), and the rollover main determination circuit 52 and the OR circuit 53e When the output signal is a low level signal (“No”), the low level signal is output to the ignition device 60L (step S19).

  As described above, according to the rollover judging device 50 according to the present embodiment, the exponential smoothing averaging process is used as the signal process applied to the output signals of the Y-axis acceleration sensor 30 and the Z-axis acceleration sensor 40, thereby performing the signal process. It is possible to stably determine the occurrence of an accident (rollover) with a long event duration while preventing an increase in memory space required for the operation. Therefore, according to the SRS airbag system including such a rollover judging device 50, the occurrence of an accident with a long event duration (rollover) is stably determined, and the curtain airbags 70R and 70L are reliably deployed when the rollover occurs. Thus, the passenger can be protected.

In addition, this invention is not limited to the said embodiment, The following modifications can be considered.
(1) In the above embodiment, exponential smoothing average is used for signal processing applied to the output signals of the Y-axis acceleration sensor 30 and the Z-axis acceleration sensor 40 in the safing circuit 53. However, the present invention is not limited to this. Exponential smoothing averaging may also be used for signal processing of the output signal.

(2) In the above embodiment, the SRS airbag system that prevents the passenger from being released to the outside by detecting the rollover of the vehicle and deploying the curtain airbag has been described as an example. In addition to rollover, the airbag system detects that a frontal collision or side collision has occurred based on output signals from the front crash sensor, side impact sensor, etc. It often has a function of deploying a side airbag, and exponential smoothing averaging processing may be used as signal processing of the output signal of such a front crash sensor or side impact sensor.
Furthermore, when the vehicle collides with a pedestrian, even in a pop-up hood system that lifts the engine hood and reduces the obstacles to the pedestrian, the acceleration sensor is used to determine the occurrence of a collision with the pedestrian. Exponential smoothing averaging processing may be used as signal processing of the output signal of such an acceleration sensor.

(3) In the above embodiment, exponential smoothing average is used as signal processing applied to the output signals of the Y-axis acceleration sensor 30 and the Z-axis acceleration sensor 40. In addition, time series data such as moving average and exponential moving average are used. The smoothing method may be used.

1 is a schematic configuration diagram of a vehicle rollover protection system (SRS airbag system) including a vehicle rollover determination device (rollover determination device 50) according to an embodiment of the present invention. It is detailed explanatory drawing of the vehicle rollover determination apparatus (rollover determination apparatus 50) which concerns on one Embodiment of this invention. It is a flowchart showing operation | movement (especially rollover determination operation | movement by the rollover determination apparatus 50) of the SRS airbag system which concerns on one Embodiment of this invention. It is the 1st explanatory view about rollover judging operation by rollover judging device 50 concerning one embodiment of the present invention. It is the 2nd explanatory view about rollover judging operation by rollover judging device 50 concerning one embodiment of the present invention.

Explanation of symbols

 DESCRIPTION OF SYMBOLS 100 ... Vehicle, 10 ... SRS unit, 20 ... Angular velocity sensor, 30 ... Y-axis acceleration sensor, 40 ... Z-axis acceleration sensor, 50 ... Rollover judging device, 60R, 60L ... Ignition device, 70R, 70L ... Curtain airbag, 51 ... interval integration circuit, 52 ... rollover main determination circuit, 53 ... safing circuit, 54, 55 ... AND circuit, 53a ... first exponential smoothing average circuit, 53b ... second exponential smoothing average circuit, 53c ... 1 comparison circuit, 53d, second comparison circuit, 53e, OR circuit

Claims (4)

A vehicle rollover determination device that determines the occurrence of vehicle rollover based on a value obtained by performing predetermined signal processing on an output signal of an acceleration sensor that detects acceleration installed at a predetermined location of a vehicle,
A vehicle rollover comprising: an output signal of the acceleration sensor as input, and a signal processing means for outputting a value obtained by performing signal processing on the output signal of the acceleration sensor using a time-series data smoothing technique. Judgment device.  The vehicle rollover judging device according to claim 1, wherein the signal processing means uses exponential smoothing average as a smoothing method of the time series data. The signal processing means is a signal based on the exponential smoothing average based on the following equation (1) consisting of an input signal X (n), an integration time constant α, a sampling frequency fs, an integration time t, and an output value Y (n). The vehicle rollover judging device according to claim 2, wherein processing is performed.
Y (n) = α · X (n) + (1−α) · Y (n−1) (1)
However, α = 2 / (1 + fs · t) An acceleration sensor for detecting acceleration installed at a predetermined location of the vehicle;
A protection device for protecting a party of the vehicle rollover when the vehicle rollover occurs;
The vehicle rollover determination device according to any one of claims 1 to 3, wherein occurrence of vehicle rollover is determined based on an output signal of the acceleration sensor.
A protection activation device that activates the protection device according to a determination result of occurrence of vehicle rollover by the vehicle rollover determination device;
A vehicle rollover protection system comprising:

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