JP5440476B2 - Vehicle collision detection device - Google Patents

Description

  The present invention relates to a vehicle collision detection device that detects an object collision based on a pressure change in a bumper.

  Pedestrian protection devices that reduce damage to pedestrians when a vehicle collides with pedestrians have been put into practical use. This pedestrian protection device instantly raises the rear end of the engine hood after collision detection in order to reduce the impact of the pedestrian hitting the engine hood, and supports the increased stroke with a buffer mechanism. It is called by names such as pop-up hood, pop-up engine hood, active bonnet, and active hood. In addition, there is an airbag that is deployed from the engine hood outside the vehicle body to the lower part of the front window to directly buffer the impact of a pedestrian, and is called by a name such as a cowl airbag or a hood airbag.

  In these apparatuses, a collision detection device is provided in the bumper unit, and it is detected that an object has been contacted using a sensor, and the device is operated when it is determined that the contacted object is a human body. It is harmful when the pedestrian protection device is activated. For example, it impairs the driver's field of view, which is dangerous when the speed is high, and once it is activated, repairs are required, and repair costs are incurred. Further, in a serious collision such that the engine compartment is crushed, there is a risk that the engine hood whose rear end is raised by operating the device will break through the windshield and enter the passenger compartment, causing harm to the passengers. Therefore, if the target of collision is something other than a human body, or if the effect is not expected even if the speed is too high or too low, the device will not operate by accurately determining the type of collision object. It is desirable.

  Conventionally, a chamber member is provided in a bumper, and the type of collision object is determined by detecting a pressure change in the chamber at the time of collision, and further, damage is determined for each component constituting the apparatus. A vehicle collision detection device has been proposed (for example, Patent Document 1).

  In the vehicle collision detection device described in Patent Document 1, when an object collides with the bumper, the chamber member disposed on the front surface of the bumper force is deformed in the bumper, thereby causing a pressure change in the chamber. The change is detected by a pressure sensor. The collision detection device calculates an effective mass from the kinetic energy based on the detection result of the pressure change by the pressure sensor, and determines whether the collision object is a pedestrian or a failure of the detection device.

  The failure determination of the detection device is not only when the pedestrian protection device is actually activated, but also when the object is touched at a low speed at which the pedestrian protection device does not operate and it is determined that the chamber member is assumed to be broken. Set to determine. For example, when moving at a low speed with the steering wheel turned off at a parking lot, if the corner of the bumper is slightly touched to the fence or pillar by mistaking the minimum turning radius, or when leaving the parallel parking, If a car is moved with a bumper to make space and get out of the parking line, the chamber may be damaged. When a collision with a pedestrian occurs without knowing the state in which the chamber is damaged, no pressure is generated assuming a collision with the pedestrian, and the pedestrian protection device cannot be activated. Therefore, by calculating the effective mass from the kinetic energy and comparing it with a predetermined value, the chamber may be damaged when it collides with an object at a speed lower than the speed at which the pedestrian protection device should be operated. As there is, it is configured to notify the driver of the failure of the collision detection device by an alarm device. Therefore, the driver who recognizes the failure of the collision detection device by the notification by the alarm device can move the vehicle to a repair shop or the like and receive repair.

JP 2010-70129 A

  However, even if the driver recognizes the failure of the collision detection device by an alarm device, it may not be possible to repair the vehicle immediately. Colliding with a person can happen in reality. In addition, there is a possibility of colliding with a pedestrian when the device is used ignoring the failure notification or is scheduled to be repaired at a later date and used continuously.

  The present invention has been made in view of the above problems, and in a vehicle collision detection device that detects a pressure change inside a chamber member disposed in a bumper, the chamber member is damaged even after a predetermined amount of damage. An object of the present invention is to provide a vehicle collision detection device capable of performing collision detection.

The invention of claim 1 has been made in order to achieve the above object, a pressure sensor for detecting a chamber member internal to the chamber space disposed within the bumper is formed, the pressure of the chamber space, the pressure A collision determination unit configured to determine collision of an object with a bumper based on a pressure detection result by the sensor. In a vehicle collision detection device configured to determine damage to the bumper based on the pressure detection result by the pressure sensor A collision determination unit, a failure notification unit for notifying a failure of the vehicle collision detection device when the damage determination unit determines that the bumper has received a predetermined damage or more, and a collision based on a pressure detection result by the pressure sensor. When the effective mass calculation means for calculating the effective mass of an object and the damage determination means determine that the bumper has received more than a predetermined amount of damage It includes a threshold value changing means for changing the threshold value of collision determination means, a collision determination means, also hereinafter the said bumper by the damage determination means determines that received a predetermined or damage, effective calculated by the effective mass calculation means The collision is determined by comparing the mass with a threshold value .

  According to this configuration, even after it is determined by the damage determination means that the bumper has received a predetermined damage or more, the collision determination means performs the collision determination, so that the walk before the vehicle collision detection device is repaired is repaired. It is possible to reliably detect a collision even when a collision accident with a person or the like occurs.

  In other words, a passenger of a vehicle in which a collision of an object with a bumper has received a notification from the failure notification means recognizes that the vehicle collision detection device immediately after the collision is abnormal and goes to a repair factory or the like. In the event of a collision with a pedestrian, the collision detection device for a vehicle can detect a collision, so if there is a collision that requires the activation of the pedestrian protection device, the pedestrian can be protected. It becomes possible.

Further , since the threshold value of the subsequent collision determination means is changed after the bumper is damaged, it is possible to detect the collision of a pedestrian or the like even when the collision detection performance is reduced due to the damage.

The invention according to claim 2 is characterized in that the threshold value changing means changes the threshold value according to the magnitude of the effective mass when it is determined that the damage determination means has received a predetermined amount or more of damage.

  According to this configuration, according to the magnitude of the effective mass when the threshold value changing means is determined to have received the predetermined damage or more by the damage determination means (in other words, according to the rate at which the chamber is broken), A threshold can be set. For example, if the damage is low, the threshold is slightly lower than normal, and if the damage is severe, the threshold is lower. A collision can be detected. In addition, since the threshold value is not lowered too much, it is possible to prevent malfunction from being caused by slight contact.

The invention described in claim 3 is characterized in that the effective mass calculating means obtains the effective mass from the pressure detection result by the pressure sensor using the relationship between the momentum and the impulse. According to this configuration, when determining the effective mass, it is only necessary to divide by the magnitude of the speed, so that the accuracy of the collision determination and the damage determination is improved.

The invention according to claim 4 is characterized in that the threshold value changing means changes the threshold value of the collision determination means to a smaller value when it is determined by the damage determination means that the bumper has received a predetermined damage or more. According to this configuration, when it is determined by the damage determination means that the bumper has received damage greater than or equal to the predetermined value, the threshold value of the collision determination means is changed to a smaller value. Even if the pressure is small, it is possible to reliably detect a collision.

The invention according to claim 5 is characterized in that the threshold value changing means changes the threshold value to a smaller value as the effective mass is larger when it is determined by the damage determining means that the damage is more than a predetermined amount. And According to this configuration, the greater the damage, the greater the possibility of breakage of the chamber, that is, there is a possibility that the hole will open larger. Therefore, the collision can be reliably determined by lowering the threshold value.

The invention according to claim 6 is characterized in that the collision determination means operates the pedestrian protection device when the effective mass calculated by the effective mass calculation means is equivalent to a pedestrian. According to this structure, a pedestrian can be protected when it collides with a pedestrian.

The invention described in claim 7 is characterized in that the pedestrian protection device is at least one of a pop-up hood and a cowl airbag. According to this structure, the obstacle to a pedestrian's head can be suppressed when it collides with a pedestrian.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the collision detection apparatus for vehicles which concerns on embodiment of this invention, (a) is a schematic diagram which shows each component with the schematic longitudinal cross-section of a bumper, (b) is a functional block which shows a hardware structure FIG. It is a figure showing the composition of the collision detection device for vehicles concerning the embodiment of the present invention from the viewpoint from the vehicles upper part. It is a conceptual diagram imitating the impact from a collision object. It is a flowchart which shows the process of the controller in the collision detection apparatus for vehicles which concerns on embodiment of this invention.

Hereinafter, specific embodiments of the vehicle collision detection device of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1A, 1B, and 2, the vehicle collision detection device 10 according to the embodiment of the present invention detects a collision of an object with the bumper 1 in front of the vehicle, and a pedestrian protection device. 21 is a device configured to activate 21, a bumper 1, a chamber member 2 disposed in the bumper 1, in which a chamber space 2 a is formed, and a pressure sensor that detects a pressure change in the chamber space 2 a 3 and a controller 11. The controller 11 functions as various means to be described later based on the detection results of the sensors.

  As shown in FIGS. 1A and 2, the bumper 1 is mainly composed of a bumper force 4, a chamber member 2, and an absorber 5.

  The bumper force 4 is an existing metal beam-like member that is disposed in the bumper 1 and extends in the vehicle width direction, and is a pair of metal members that are positioned on the side surface of the vehicle and extend in the vehicle front-rear direction. It is attached to the front end of the existing side member 6 which is a member.

  The chamber member 2 is a hollow member made of a synthetic resin such as polyethylene, which is attached to the upper front surface of the bumper force 4 in the bumper 1 and extends in the vehicle width direction, and has a pressure transmission function in the bumper 1. . A chamber space 2 a is formed inside the chamber member 2. The chamber space 2a is a closed space, but is not hermetically sealed, and is communicated with the outside air in some narrow portions and is at atmospheric pressure. As a result, it is not affected by changes in atmospheric pressure due to altitude differences or temperature changes. A pressure receiving portion of the pressure sensor 3 is inserted into the chamber space 2a through an insertion port (not shown). An absorber 5 is disposed below the chamber member 2. The absorber 5 is a member having an impact absorbing function in the bumper 1. For example, a foamed resin or the like can be used. Further, one chamber space 2a may be provided in the chamber member 2, but a plurality of chamber spaces 2a may be provided in the vehicle width direction.

  The pressure sensor 3 is a sensor device that can detect a gas pressure as a load, and is assembled to the chamber member 2. Specifically, the pressure receiving portion is inserted into the chamber space 2a via the insertion port, and the pressure change of the air in the chamber space 2a can be detected. The pressure sensor 3 outputs a signal proportional to the pressure. The pressure sensor 3 is electrically connected to the controller 11 via a transmission line. When a plurality of chamber spaces 2a are provided in the chamber, they are provided for each chamber space 2a.

  The vehicle speed sensor 12 is an existing speed sensor that detects the magnitude of the traveling speed of the vehicle based on vehicle speed pulses, and is electrically connected to the controller 11 via a transmission line.

  The controller 11 is configured to calculate effective mass of the collision object based on the detection results of the pressure sensor 3 and the existing vehicle speed sensor 12 at the time of collision, and the collision object based on the effective mass calculated by the effective mass calculation means. It functions as a collision determination means for determining the type of the. Moreover, it functions as a damage determination means for diagnosing whether or not the vehicle collision detection device 10 normally operates based on the effective mass calculated by the effective mass calculation means and the detection result of the vehicle speed sensor 12. Furthermore, when it determines with the bumper 1 having received the damage more than predetermined by the damage determination means, it also has a function as a failure notification means for notifying the alarm device 22 of the failure of the vehicle collision detection device 10. Furthermore, since the collision determination means compares the effective mass obtained from the pressure detection result with a threshold value, the effective mass when it is determined that the bumper 1 has received damage after it is determined that the bumper 1 has received damage more than a predetermined amount. It also has a function as a threshold changing means for changing the threshold to a predetermined threshold according to the size of.

  Here, the “effective mass” refers to a mass calculated using a relationship between momentum and impulse from a signal detected by a pressure sensor at the time of collision. The bumper 1 has a function of absorbing an impact by the absorber 5 and other members, and the colliding object is also supported by the ground. Therefore, what can be calculated from the load detected by the pressure sensor is different from the actual mass. Therefore, to avoid misunderstanding, the term “effective mass” is used in the above sense.

  As described above, the controller 11 calculates the effective mass of the collision object based on the detection results of the pressure sensor 3 and the vehicle speed sensor 12, determines the type of the collision object as a pedestrian, and further activates the pedestrian protection device 21. When it is determined that the speed should be set, a signal for operating the driving device 23 of the pedestrian protection device 21 is output, and the pedestrian protection device 21 is operated. Damage determination for determining damage to the bumper 1 when it is determined that the type of the collision object is not a pedestrian, or when it is determined that the collision object is not a speed at which the pedestrian protection device 21 should be operated even if the collision object is a pedestrian When the process is executed and it is determined that the bumper 1 has been damaged more than a predetermined amount, a failure notification process for notifying the alarm device 22 of a failure of the vehicle collision detection device 10 is executed, and the failure determination is performed as data. 11, the RAM 24 stores data as failure history information for repair, and the stored information is read out by a diagnostic device separately prepared for maintenance and maintenance. It is used as information for determining whether or not. The controller 11 continues to calculate the effective mass of the collision object based on the detection results of the pressure sensor 3 and the vehicle speed sensor 12 and to determine the type of the collision object.

  The pedestrian protection device 21 may be a known device called by a name such as a pop-up hood, a pop-up engine hood, an active bonnet, an active hood, a cowl airbag, a hood airbag, or the like. It is lifted and the stroke of the raised part is supported by a buffer mechanism, so that the impact that the pedestrian hits the engine hood is softened or protected, or it is called the name of a cowl airbag, hood airbag, etc. An airbag is deployed from the top of the engine hood to the lower part of the front window to cushion the impact of pedestrians. The alarm device 22 is composed of known parts, and notifies the occupant of the failure based on the output from the controller 11, for example, by voice or display in the meter.

  Next, the collision determination process in this embodiment will be described with reference to the drawings. FIG. 3 is a conceptual diagram simulating an impact from a collision object. As is apparent from the figure, when the object collides with the bumper 1, the chamber member 2 is deformed and the volume of the chamber space 2a changes rapidly. The gas pressure increases. A change in the gas pressure in the chamber space 2 a is electrically detected by the pressure sensor 3.

  The controller 11 captures a signal output from the pressure sensor 3 via the transmission line and also captures a vehicle speed signal from the vehicle speed sensor 12. Further, the effective mass of the collision object is calculated based on the output from the pressure sensor 3 and the vehicle speed, and it is determined whether the collision object is a pedestrian or the like based on whether the calculated effective mass is larger than a predetermined threshold value. To do.

  When a collision with the vehicle occurs, the detected value of the pressure sensor 3 differs for a collision object having a mass different from that of a pedestrian. Therefore, the effective mass of the collision object is calculated from the detection output of the pressure sensor 3, and this About the effective mass, by setting a threshold value between the effective mass of the human body and the mass of another assumed collision object, the type of the collision object can be separated. Since the product of the detection output of the pressure sensor 3 and the detection time is equal to the momentum due to the collision with a certain effective mass colliding at a certain speed, the effective mass of the collision can be calculated from the vehicle speed at the time of the collision.

Hereinafter, the calculation method of the effective mass in this embodiment is demonstrated. Referring to FIG. 3, when the vehicle collides with an object of a stationary mass M at a certain speed V, the object of mass M is directed toward the stationary pressure sensor 3 as viewed from the pressure sensor 3. It can be considered that the vehicle collided at a velocity magnitude V. At this time, if the vehicle speed detection value at the time of the collision is V, the duration of the collision is Δt, and the applied load is F, the well-known relational expression of momentum and impulse MV = FΔt (1)
Therefore, the mass can be calculated as M = FΔt / V.

When a collision object of a certain mass M collides with the bumper 1 at a certain collision speed (vehicle speed detection value by the vehicle speed sensor 12) V, the collision load F is transmitted to the chamber member 2 and the chamber space 2a is crushed and the volume changes. To do. Since the pressure in the chamber space 2a increases due to this volume change, the pressure sensor 3 detects the pressure. Since the pressure sensor 3 substantially detects the load, the pressure detection value can be handled in the same manner as the load. The value of the pressure sensor 3 may be an average value for a predetermined time of several milliseconds to several tens of milliseconds in order to prevent erroneous detection due to noise or the like, and the duration time Δt may be integrated as an integration time for averaging, The effective mass is calculated from the equation (1). M = (∫P (t) dt) / V (2)
Can be obtained. Note that the coefficients are ignored. Further, since the magnitude of the collision speed uses a value taken in as a vehicle speed detection value by the vehicle speed sensor 12, it is handled as a constant when calculating the effective mass.

Note that the method of calculating the effective mass, from the equation E = ^MV 2/2 of the other into kinetic energy, there is also a calculation method as M = 2E / ^{V 2.} However, since the vehicle speed detection value by the vehicle speed sensor uses vehicle speed pulses, the accuracy is poor at low speed, and the vehicle speed detection value with poor accuracy is squared. Therefore, here, the relationship between the momentum and impulse is simply divided by the vehicle speed detection value, and the accuracy is improved over the method using kinetic energy.

  Actually, it is not the pressure sensor 3 but the surface of the bumper 1 that the object collides while the vehicle is running, and there is also the influence of the impact absorption by the chamber member 2 and the absorber 5. The coefficient shall be obtained. The correction coefficient is held in the ROM 26 or RAM 24 in the controller 11. In this way, accurate determination can be made.

  Similarly, a condition for damaging the chamber member 2 is obtained by an experiment, and a threshold value Mth_d is set in consideration of an error, so that a chamber failure can be reliably determined. After determining the chamber failure, the alarm device 22 is activated to notify the occupant of the failure. Furthermore, after this, the vehicle collision detection device 10 continues detection and prepares for a new collision.

  Next, based on the flowchart shown in FIG. 4, the flow of the process of the controller 11 in the vehicle collision detection apparatus 10 of this embodiment is demonstrated. When there are a plurality of pressure sensors 3, the flow of FIG. 4 is performed for each pressure sensor 3.

<Procedure for determining the type of collision object>
The controller 11 stores a collision detection program in the ROM 26 or the RAM 24, and the CPU 25 executes each process described below according to the program. As shown in FIG. 4, the controller 11 performs a process of initializing a calculation value as an initial process (step S-1).

  Subsequently, the controller 11 reads the vehicle speed detection value V detected by the vehicle speed sensor 12 (step S-2), further reads the output of the pressure sensor 3 for a predetermined time, and calculates the effective mass (step S-3, step S-). 4). The value of the pressure sensor 3 is integrated with the time during which the pressure value is detected so that an average value over a predetermined time of several milliseconds to several tens of milliseconds is used in order to prevent erroneous detection due to noise or the like. The effective mass is obtained by the equation (2), M = (∫P (t) dt) / V.

  In the next step S-5, the controller 11 determines whether or not the calculated effective mass M is greater than or equal to a predetermined threshold value Mth. If it is equal to or greater than the threshold value Mth (Yes in step S-5), the collision object is determined to be a pedestrian, and the process proceeds to the next step (step S-6). If it is not equal to or greater than the threshold value Mth (No in step S-5), the process proceeds to another step (step S-8) in which it is determined whether the collision object is an object that causes chamber damage.

  In step S-6, the vehicle speed detection value V read in step S-2 is used again and compared with predetermined ranges of Vmax and Vmin. When the vehicle speed detection value V is within this range, the controller 11 outputs a signal for operating the pedestrian protection device 21 (step S-7). When the vehicle speed detection value V is not within this range, the process proceeds to another step (step S-9) in order to determine whether or not the collision object has a speed that causes the chamber damage.

  Vmax is set as an upper limit speed at which the pedestrian protection device 21 is effective. In other words, at speeds exceeding Vmax, the pedestrian is rebounded beyond the range of the engine hood, so there is no effect even if the pedestrian protection device 21 such as a pop-up hood is operated. In addition, when the pedestrian protection device is activated, it is dangerous because it obstructs the driver's view. Furthermore, it is conceivable that the vehicle will continue to collide with other objects at a high speed, and if the engine room is severely collided, the pedestrian protection device 21 such as a pop-up hood will operate and the rear end will The rising engine hood may break through the windshield and enter the passenger compartment, causing harm to the passengers. For this reason, the pedestrian protection device 21 is not operated at a speed exceeding Vmax.

  Further, Vmin is set as a lower limit speed at which the pedestrian protection device 21 has an effect. That is, at a speed lower than Vmin, the pedestrian cannot be lifted up on the engine hood, or even if the pedestrian is lifted up, the pedestrian protection device 21 is not effective because it is not strongly hit against the engine hood. Therefore, at a speed smaller than Vmin, the pedestrian protection device 21 is not activated.

  In addition, what is determined as Yes in step S-5 is an object having a mass more than that of a pedestrian. For example, in the case of contact in a parking lot, step S-5 is determined as Yes. Become. However, if the magnitude of the speed at that time is smaller than Vmin, the process proceeds to another step (step S-9) to determine whether or not the object has the magnitude of the speed causing the chamber breakage, and the damage is judged. become.

<Damage judgment>
In step S-8, the effective mass M calculated in step S-4 is compared with a threshold value Mth_d for further determining damage. The threshold value Mth_d is a value smaller than the threshold value Mth used in step S-5. When the effective mass M is greater than or equal to the threshold value Mth_d (Yes in step S-8), it is assumed that an object having an effective mass M smaller than that of a pedestrian, such as a movable display board placed on a road construction site, is touched. Determine and proceed to the next step (step S-9). If the effective mass M is not equal to or greater than the threshold value Mth_d (No in step S-8), it is assumed that the chamber does not collide with anything that damages the chamber, and the process returns to step S-2 assuming that there is no damage.

  In step S-9, the vehicle speed detection value V read in step S-2 is used again and compared with a speed threshold value Vth_d for determining damage. The threshold value Vth_d is a value smaller than the threshold value Vmin. If the vehicle speed detection value V is greater than or equal to the threshold value Vth_d (Yes in step S-9), it is determined that the chamber member 2 has been damaged and broken, and a signal is sent to the alarm device 22 to display a sensor failure (step). S-10). If the vehicle speed detection value V is not equal to or higher than the threshold value Vth_d (No in step S-9), the process returns to step 2 assuming that there is no damage because the contact is made at a low speed. The threshold value Vth_d is assumed to be larger than at least a value (about 5 km / h) that is not allowed to impair the function even when the vehicle is in contact with some object.

  Here, when it is determined that the chamber member 2 is broken, “sensor failure” is displayed as a sensor failure even when a failure of the pressure sensor element or each circuit is detected by a separately prepared detection circuit. This is because the passenger is notified to inform the passenger that repair is necessary. The threshold value Mth_d is set so that a chamber that breaks the chamber can be found from experiment and market information, and for example, a movable display board placed on a road construction site can be determined.

  In step S-10, after sending a signal to the alarm device 22 to display a sensor failure (step S-10), in step S-11, the threshold value when it is determined that the chamber member 2 is damaged at the threshold value Mth. Substitute Mth_chd and return to step S-2. The new threshold value Mth to which this threshold value Mth_chd is substituted is held until the repair is completed. The threshold value Mth_chd has a value smaller than the threshold value Mth used in the most recent step S-5. Since the threshold value Mth used in the subsequent step S-5 is smaller than the threshold value Mth before the collision, it is determined that the pedestrian collides with a smaller effective mass M. This is because the pressure detected by the pressure sensor 3 is expected to be smaller than expected even if the chamber member 2 is damaged and the same collision occurs. By doing so, the controller 11 determines that the chamber member 2 has been damaged and broken, and the alarm device 22 displays a sensor failure, and then the driver who has recognized this heads for a repair shop or ignores it. Even in the case of continued use, the vehicle collision detection device 10 functions when it collides with a pedestrian on the way.

  As is apparent from the above description, according to the present embodiment, when a collision object collides with the bumper 1, the collision determination means (S-4 to S-6) for determining the collision of the object with the bumper 1. A damage determination means (S-8, S-9) for determining damage to the bumper 1, and a failure notification means for notifying the failure when the damage determination means determines that the bumper 1 has received a predetermined damage or more ( In the vehicular collision detection device 10 having S-10, the alarm device 22), the collision determination unit performs the collision determination even after the damage determination unit determines that the bumper 1 has received a predetermined damage or more. .

  Therefore, even when a collision accident with a pedestrian or the like occurs before the failure of the vehicle collision detection device 10 is repaired, it is possible to reliably detect the collision.

  That is, when a vehicle occupant having a collision of an object with the bumper 1 is notified by the failure notification means (S-10, alarm device 22), the vehicle collision detection device 10 immediately after the collision is abnormal. The vehicle collision detection device 10 can detect a collision even in the event of a collision with a pedestrian on the way, so the pedestrian protection device 21 needs to be activated. In the event of a collision, it is possible to protect pedestrians.

  Moreover, according to this embodiment, the effective mass calculation means (S-3, S-4) for calculating the effective mass of the collision object based on the pressure detection result by the pressure sensor is provided, and the collision determination means is the effective mass calculation means. The effective mass calculated by the threshold value is compared with a threshold value, and the threshold value changing means (S-11) for changing the threshold value Mth of the collision determining means after it is determined by the damage determining means that the bumper 1 has received a predetermined damage or more. ), After the bumper is damaged, the pedestrian protection device 21 can be operated even if the pressure detected at the time of the collision is different due to the decrease in the collision detection performance. it can.

  Further, according to the present embodiment, the effective mass calculation means (S-3, S-4) obtains the effective mass M (t) from the pressure detection result using the relationship between the momentum and the impulse, and therefore, particularly in the low speed range. It can be set as the vehicle collision detection apparatus 10 which can perform more accurate collision determination and damage determination than those using kinetic energy.

  In addition, according to the present embodiment, the threshold value changing means (S-11) changes the threshold value Mth of the collision determination means (S-5) to a smaller value Mth_chd when it is determined that the bumper has received a predetermined damage or more. Therefore, even if the chamber member 2 is damaged and the pressure detected at the time of the collision is small, the collision can be reliably detected.

  Moreover, according to this embodiment, the magnitude | size of the effective mass M when a threshold value change means (S-11) determines with the damage determination means (S-8, S-9) having received the damage more than predetermined. Since the threshold value is changed to a smaller value as the value increases, the damage to the chamber may increase as the damage increases, i.e., the hole may open larger. Judgment can be made.

  Moreover, according to this embodiment, when the collision determination means (S-5) is equivalent to the pedestrian when the effective mass M calculated by the effective mass calculation means (S-3, S-4) is equivalent to the pedestrian. Since the protective device 21 is operated, the pedestrian can be protected when colliding with the pedestrian.

  Moreover, according to this embodiment, since the pedestrian protection device 21 is at least one of a pop-up hood and a cowl airbag, it is possible to suppress an obstacle to the pedestrian's head when colliding with the pedestrian. it can.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  For example, the RAM 24 may be a storage device that is external to the controller 11 and that centrally stores vehicle information.

  Further, the threshold value Vth_d in S-9 may not be a single one. That is, the table may be selected in the RAM 24 or the ROM 26 as related to the calculated effective mass M from the condition that the chamber member 2 obtained by the experiment is damaged.

  Moreover, in the said embodiment, although it was set as the structure which performs step S-11 after operating an alarm device by step S-10, it is good also as a structure which returns to step S-2 from step S-10. That is, the threshold value Mth_chd need not be substituted. This is because in the case of such failure detection, the threshold value Mth_d is set in consideration of an error on the safe side. In other words, “chamber breakage → failure display” (if the chamber is broken, the failure display is always displayed), and “reverse failure display → chamber breakage” (if the failure is displayed) is in the opposite relation. The chamber is always broken) does not hold. Even if a failure is detected, the chamber member 2 may not actually be damaged. Therefore, even if it is determined Yes in step S-9, the chamber member 2 may not be damaged. In this case, since the flow from step S-2 is continued, the vehicle collision detection device 10 functions when there is a collision with a pedestrian. Further, if the degree of damage of the chamber member 2 is small, the calculated effective mass M becomes equal to or greater than the threshold value Mth, and the possibility that a pedestrian collision can be detected remains.

  Further, when executing step S-11, the threshold value after the chamber member 2 is damaged is set to, for example, Mth_chd1, Mth_chd2,..., Mth_chdn according to the size of the effective mass calculated in step S-4. Thus, a plurality of prepared ones may be selected and substituted for Mth. In this way, since the threshold value Mth that anticipates a decrease in the detected pressure is set according to the degree of breakage, the driver 11 uses it even though the alarm device 22 displays a sensor failure by the signal from the controller 11. Even if it continues, when it collides with the pedestrian on the way, the vehicle collision detection apparatus 10 functions more reliably.

DESCRIPTION OF SYMBOLS 1 Bumper 2 Chamber member 2a Chamber space 3 Pressure sensor 4 Bumper force 5 Absorber 6 Side member 10 Vehicle collision detection apparatus 11 Controller (Effective mass calculation means, collision judgment means, damage judgment means, failure notification means, threshold change means)
12 Vehicle speed sensor 21 Pedestrian protection device 22 Alarm device 23 Drive device 24 RAM
25 CPU
26 ROM

Claims (7)

A chamber member disposed in the bumper and having a chamber space formed therein;
A pressure sensor for detecting the pressure in the chamber space;
A collision determination means for determining a collision of an object with the bumper based on a pressure detection result by the pressure sensor;
In a vehicle collision detection device configured to include:
Damage determination means for determining damage to the bumper based on a pressure detection result by the pressure sensor;
A failure notifying means for notifying a failure of the vehicle collision detection device when it is determined by the damage determining means that the bumper has received a predetermined damage or more;
Effective mass calculating means for calculating the effective mass of the collision object based on the pressure detection result by the pressure sensor;
A threshold value changing means for changing a threshold value of the collision determination means when it is determined by the damage determination means that the bumper has received a predetermined damage or more;
With
The collision determination unit is configured to determine a collision by comparing the effective mass calculated by the effective mass calculation unit with the threshold value even after the damage determination unit determines that the bumper has received a predetermined damage or more. A vehicle collision detection device configured to perform the above. The threshold value changing means, vehicle according to claim 1, in accordance with the effective mass size when it is determined that received a predetermined or more damaged by the damage determination unit, and changes the threshold value Collision detection device. The effective mass calculation means for a vehicle collision detection apparatus according to claim 1 or 2, characterized in that to determine the effective mass by using the relationship between the momentum and the impulse from the pressure detection result by the pressure sensor. The threshold value changing means, according to claim 1, wherein changing the threshold of the collision determining means to a smaller value when the bumper is determined to have received a predetermined or more damaged by the damage determination means The vehicle collision detection device according to any one of the above. The threshold value changing means, the more the damage determination means is larger the effective mass of the size when it is determined that received a predetermined or damage, claim and changes the threshold value to a smaller value 1 The collision detection apparatus for vehicles as described in any one of thru | or 4 . The collision determination unit, when the said effective mass calculated by the effective mass calculation means is equivalent pedestrian, in any one of claims 1 to 5, characterized in that actuating the pedestrian protection apparatus The vehicle collision detection device as described. The vehicle collision detection device according to claim 6 , wherein the pedestrian protection device is at least one of a pop-up hood and a cowl airbag.

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