JP2005053425A - Vehicle pedestrian protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a pedestrian accurately by accurately detecting the collision when a vehicle collides with a pedestrian.
SOLUTION: A bumper sensor 21 including a plurality of sensor cells that are arranged in a row in the vehicle width direction and that respectively detects a load applied to the bumper 16 at each arrangement position is assembled to the bumper 16. The electronic control unit 30 detects the collision of the vehicle with the pedestrian based on the distribution pattern of each load detected by the plurality of sensor cells. For example, a pedestrian collision is determined on the condition that about 3 or 4 sensor cells that detect a load equal to or greater than the threshold are continuous. At the time of determination of a pedestrian collision, the electronic control unit 30 drives and controls the left and right hood actuators 14 and 15 to flip up the rear part of the hood 11 to protect the pedestrian. Further, a temperature sensor 22 is disposed in the vicinity of the bumper 16, and the detection value of each sensor cell of the bumper sensor 21 is temperature-corrected.
[Selection] Figure 1

Description

  The present invention relates to a pedestrian protection device for a vehicle that protects a pedestrian when the vehicle collides with a pedestrian.

Conventionally, a pedestrian protection device for a vehicle that protects a pedestrian when the vehicle collides with a pedestrian is known. In this pedestrian protection device, a plurality of displacement sensors or load sensors are arranged along the vehicle width direction on the bumper, and the amount of bumper displacement detected by the plurality of displacement amount sensors or load sensors at the time of vehicle collision or Pedestrian protection such as adding the load applied to the bumper, detecting a vehicle collision with a pedestrian based on the combined displacement or load, and raising the hood when a vehicle collision with the pedestrian is detected The device is operated (see, for example, Patent Document 1).
JP-A-11-28994

  However, in the above-described conventional apparatus, since the collision of the vehicle to the pedestrian is detected based on the sum of the displacement amount or the load of each position along the vehicle width direction of the bumper, When a vehicle collides with a pedestrian at the same time, the total amount of displacement or load may become too large to detect a collision with a pedestrian.

  The present invention has been made to cope with the above-described problem, and its purpose is to accurately detect a collision of a vehicle with a pedestrian and to accurately protect the pedestrian during the detection. A person protection device is provided.

  In order to achieve the above object, the present invention is characterized by a pedestrian protection device for protecting a pedestrian when the vehicle collides with the pedestrian, and a bumper disposed along the vehicle width direction. A plurality of load sensors that respectively detect the load applied to the bumper at the position, and a pedestrian collision detection unit that detects a collision of the vehicle with the pedestrian by each load distribution pattern detected by the plurality of load sensors; When the collision with the pedestrian is detected by the pedestrian collision detecting means, an operation control means for operating the pedestrian protection device is provided. In this case, for example, the pedestrian collision detection means can be configured to detect a collision of the vehicle with the pedestrian when the load detected by at least two adjacent load sensors is equal to or greater than a predetermined threshold. In addition, as a pedestrian protection device, a hood is flipped up, an airbag is developed on the hood, and the like.

  In the present invention configured as described above, the collision of the vehicle with the pedestrian is detected by each load distribution pattern detected by a plurality of load sensors. In a vehicle collision with a pedestrian, the collision width of a single person on a bumper is almost constant. Therefore, even when a vehicle collides with a plurality of pedestrians at the same time, according to the present invention, The vehicle collision is accurately detected. Therefore, the protection of the pedestrian at the time of a vehicle collision is achieved accurately.

  Another feature of the present invention is that the pedestrian collision detection means further detects the collision of the vehicle with the pedestrian by further adding a condition that the integrated value of the load detected by the load sensor is within a predetermined range. To do. According to this, since the collision of the vehicle with the pedestrian is detected with higher accuracy, the pedestrian at the time of the collision of the vehicle is more accurately protected.

  In addition, another feature of the present invention is that temperature detecting means for detecting an environmental temperature in which a plurality of load sensors are arranged, and a load detected by the load sensor according to the temperature detected by the temperature detecting means are corrected. And a temperature correcting means for providing the temperature correction. According to this, even if the temperature changes, the accuracy of the load detected by the load sensor becomes good, and as a result, the vehicle collides with the pedestrian and the pedestrian can be properly protected at the time of the vehicle collision.

  Another feature of the present invention is that an acceleration sensor for detecting the acceleration of the vehicle is further provided, and the operation control means further includes an acceleration detected by the acceleration sensor or a physical quantity related to the acceleration at least a predetermined value or more. The pedestrian protection device is operated on the condition that it is. According to this, even if a collision with a pedestrian is erroneously detected due to an abnormality in the load sensor, the pedestrian protection device operates on condition that the acceleration detected by the acceleration sensor is at least a predetermined value or more. It is possible to prevent the operation of the pedestrian protection device when the sensor is abnormal.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing a front portion of a vehicle. As shown in FIG. 2A, a link mechanism 12 is assembled to the rear end of the hood 11 that covers the engine room of the vehicle. The link mechanism 12 is rotatably assembled to the vehicle body member BD at one end thereof, and allows the hood 11 to rotate around the rotation shaft 13 assembled to the front end portion of the vehicle. Below the left and right rear portions of the hood 11, left and right hood actuators 14 and 15 fixed to the vehicle body member BD are provided. The left and right hood actuators 14 and 15 generate a large amount of gas by igniting the gas generating agent by the ignition device, and raise the piston rods 14a and 15a by a predetermined stroke. When the piston rods 14 a and 15 a are lifted, the rear portion of the hood 11 is flipped up with the extension of the link mechanism 12 as shown in FIG.

  Next, an electric control device that controls the left and right hood actuators 14 and 15 at the time of a collision with a pedestrian will be described. As shown in FIGS. 1 and 3, the electric control device includes a bumper sensor 21, a temperature sensor 22, a left front acceleration sensor 23, and a right front acceleration sensor 24.

  As shown in FIG. 4A, the bumper sensor 21 includes a film 21A formed in a long shape, and a plurality of sensor cells 21B are fixed on the film 21A along the extending direction thereof. It is assembled to the bumper 16. Specifically, as shown in the cross-sectional view of FIG. 4B, the bumper sensor 21 is interposed between the bumper reinforcement 17 and the resin absorber 16a of the bumper 16, and the longitudinal direction of the bumper sensor 21 extends along the bumper 16. Extending in the vehicle width direction. As shown in the sectional view of FIG. 4C, each sensor cell 21B is composed of a pair of plates 21b and 21c made of a flexible material and having an elastic member 21a interposed at the peripheral edge, and one plate 21b. It consists of a pressure-sensitive ink 21d applied on top and a pair of silver electrodes 21e and 21f provided on the other plate 21c at a position facing the pressure-sensitive ink 21d. In each sensor cell 21B configured as described above, when a load is applied between the plates 21b and 21c, the resistance value between the silver electrodes 21e and 21f is changed with the solid line in FIG. As indicated by a broken line, the load changes in inverse proportion to the load. Note that the solid line and the broken line in FIG. 5 are graphs showing the relationship between the load and the resistance value at predetermined low and high temperatures, respectively. This change in resistance value is taken out as an output voltage using an electric circuit in combination with a fixed resistor.

  The temperature sensor 22 is disposed in the vicinity of the bumper 16 and detects the environmental temperature at which each sensor cell 21B is placed. The left and right front acceleration sensors 23 and 24 are assembled to a vehicle body member (not shown) near the rear of the bumper 16 and in the left and right positions in the vehicle width direction, and detect accelerations G1 and G2 generated when the bumper 16 collides with a collision target. Then, signals representing the accelerations G1 and G2 are output.

  These sensors 21 to 24 are connected to an electronic control unit 30 whose main component is a microcomputer comprising a CPU, ROM, RAM, timer and the like. The electronic control unit 30 controls the left and right hood actuators 14 and 15 by executing the pedestrian protection program of FIG. 6 every predetermined short time. The electronic control unit 30 also stores a map for converting the output voltage into a load, which represents the relationship between the output voltage (resistance value) and the load as shown in FIG. 5 relating to the sensor cell 21B. In this case, in order to perform temperature correction of the detected load by the sensor cell 21B, the map shows data indicating the relationship between the output voltage (resistance value) and the load at a predetermined low temperature (solid line in FIG. 5), and a predetermined high Data representing the relationship between the output voltage (resistance value) at temperature and the load (broken line in FIG. 5) is stored in advance.

  Next, the operation of the embodiment configured as described above will be described. The electronic control unit 30 repeatedly executes the pedestrian protection program every predetermined short time. The pedestrian protection program is started in step S10 of FIG. 6, and the output voltage of all the sensor cells 21B included in the bumper sensor 21 is input in step S12, and the map stored in the electronic control unit 30 (FIG. 5), each output voltage is converted into a load. In the process of step S12, a signal representing the temperature detected by the temperature sensor 22 is input and temperature correction is also performed. That is, the map includes two sets of data corresponding to different predetermined temperatures and representing the relationship between the output voltage and the load, and the output voltage of the sensor cell 21B is loaded by the interpolation calculation using the input detected temperature. Respectively. Therefore, the load detected by each sensor cell 21B is corrected by the temperature under the environment of each sensor cell 21B.

  Next, in step S14, the load distribution applied to the bumper 16 is pattern-recognized using the load detected and converted by each sensor cell 21B. For example, the load for each sensor cell 21B is divided into two groups: a load that is greater than or equal to a predetermined threshold and a load that is less than the threshold. Examples 1 to 5 in FIG. 7A show distribution examples in which loads that are equal to or greater than the threshold are represented by black circles, and loads that are less than the threshold are represented by white circles. FIG. 7B shows a specific example of the magnitude of the load in the distribution example of Example 2. In this case, when the bumper 16 collides with a pedestrian, the load detected by a plurality of adjacent sensor cells 21B is usually equal to or greater than a threshold value. Although it depends on the distance between the sensor cells 21B, when the load detected by the adjacent three or four sensor cells 21B is equal to or greater than the threshold, it can be set to determine the collision with the pedestrian. Therefore, in the case of FIG. 7 (B), a pedestrian and a foreign object such as a pole collide at the same time.

  Then, in step S16, it is determined whether or not it is a collision with a pedestrian according to the recognition pattern. For example, if the load detected by the three or four adjacent sensor cells 21B is equal to or greater than the threshold when the judgment condition for the collision with the pedestrian is equal to or greater than the threshold value, in FIG. The case is determined to be a collision with a pedestrian. However, in the case of Example 3, a collision with two pedestrians is determined. Thus, when the collision with a pedestrian is determined, the process after step S18 is performed based on determination with "Yes" in step S16. On the other hand, in the cases of Examples 4 and 5, a collision with a pedestrian is not detected. In this case, based on the determination of “No” in step S16, the execution of this pedestrian protection program is terminated in step S22.

  In step S18, signals representing the detected accelerations G1 and G2 are input from the left and right front acceleration sensors 23 and 24, respectively, and it is determined whether the sum G1 + G2 of the accelerations G1 and G2 has a relationship of A1 ≦ G1 + G2 ≦ A2. In this case, A1 and A2 are set to predetermined accelerations that are generated when a pedestrian collides with the bumper 16. If the sum G1 + G2 of the accelerations G1 and G2 is not in the relationship of A1 ≦ G1 + G2 ≦ A2, “No” is determined in step S18, and the execution of this pedestrian protection program program is terminated in step S22.

  On the other hand, if the sum G1 + G2 of accelerations G1 and G2 is in the relationship of A1 ≦ G1 + G2 ≦ A2, “Yes” is determined in step S18, and the left and right hood actuators 14 and 15 are controlled in step S20. Specifically, the ignition devices of the left and right hood actuators 14 and 15 are operated. As a result, the left and right hood actuators 14 and 15 start operating and raise the piston rods 14a and 15a by a predetermined stroke. As the piston rods 14a and 15a rise, the rear portion of the hood 11 is flipped up with the extension of the link mechanism 12, as shown in FIG. As a result, even if the vehicle collides with a pedestrian, the pedestrian is protected by the hood 11 that is flipped up.

  As can be understood from the above description of the operation, according to the above-described embodiment, the collision with the pedestrian is detected based on the distribution of the load detected by the plurality of sensor cells 21B of the bumper sensor 21 by the processes of steps S14 and S16. Therefore, the collision of the vehicle with the pedestrian is accurately detected. Therefore, the protection of the pedestrian at the time of a vehicle collision is achieved accurately. If the sum G1 + G2 of the accelerations G1 and G2 is not a value that is generated at the time of a collision with the bumper 16 of the pedestrian by the processing in step S18, the left and right hood actuators 14 and 15 in step S20 are not controlled. Therefore, even if an abnormality occurs in the bumper sensor 21 and a collision with a pedestrian is erroneously detected in step S16, the operation of the left and right hood actuators 14 and 15 when the bumper sensor 21 is abnormal can be prevented.

  In addition, the pedestrian protection program of FIG. 6 of the said embodiment can also be deform | transformed like the pedestrian protection program of FIG. Execution of the deformed pedestrian protection program is started in step S30, and processes in steps S32 to S36 similar to the processes in steps S12 to S16 of the above embodiment are executed. Until a load distribution pattern corresponding to a pedestrian collision is detected by the processing of these steps S32 to S36, “No” is determined in step S36, and the execution of this pedestrian program is terminated in step S54. On the other hand, when the load distribution pattern corresponding to the pedestrian collision is detected, “Yes” is determined in step S36, and the processes of steps S38 to S46 are executed.

  The process of step S38 is a process of integrating one load (or a total value of a plurality of loads) of load outputs equal to or greater than a threshold value. For example, the maximum detected load among a plurality of loads in one distribution is integrated, or the detected load at the center of gravity position in the distribution is integrated. In the process of step S40, the detected loads G1 and G2 detected by the acceleration sensors 23 and 24 are low-pass filtered. These integrated values are represented as BP ', and the low-pass filtered values are represented as G1' and G2 '. The processing in steps S42 to S46 is the same as the processing in steps S32 to S36 (steps S12 to S16 in FIG. 6), and the load distribution pattern corresponding to the pedestrian collision is detected by the processing in steps S32 to S36. As long as the determination is “Yes” in step S46, the circulation process including steps S38 to S46 is repeatedly executed.

  When the load distribution pattern corresponding to the pedestrian collision is not detected, that is, when a part of the detected load in the distribution is less than the threshold value, “No” is determined in step S46, and the determination in steps S48 and S50 is performed. Execute the process. In step S48, it is determined whether the integrated value BP ′ of one load (or a plurality of loads) by the process of step S38 is within a predetermined range, that is, whether BP1 ≦ BP ′ ≦ BP2. In this case, the predetermined values BP1 and BP2 are set in advance to load integral values that may be given to the bumper 16 by a pedestrian collision by various experiments. In step S50, it is determined whether the sum G1 '+ G2' of the accelerations G1 'and G2' subjected to the low pass processing in step S40 is within a predetermined range, that is, whether A1'≤G1 '+ G2'≤A2'. . The predetermined values A1 'and A2' are also set in advance as low-pass filter processing values for acceleration that may occur due to a pedestrian collision through various experiments.

  Then, only when the conditions of these steps S48 and S50 are satisfied, the rear portion of the hood 11 is flipped up by executing the process of step S52 similar to the process of step S20 of FIG. Otherwise, based on the determination of “No” in step S48 or step S50, the pedestrian protection program is executed in step S54 without performing the flip-up control of the hood 11 in step S54. Exit.

  According to this modification, in addition to the control of the above embodiment, the hood 11 is determined as a collision with a pedestrian only when the integral value BP ′ of the load applied to the bumper 16 is within a predetermined range. Bounce up control. Since the integral value BP ′ of the load applied to the bumper 16 corresponds well to the type of the object that has collided with the bumper 16, the collision of the vehicle with the pedestrian is detected with higher accuracy. As for the accelerations G1 and G2 detected by the acceleration sensors 23 and 24, the values G1 'and G2' obtained by low-pass filtering the accelerations G1 and G2 are more directed to the pedestrian bumper 16 than the accelerations G1 and G2 itself. Therefore, the collision of the vehicle with the pedestrian is detected with higher accuracy.

  In the pedestrian protection program of FIG. 8, when the load distribution pattern corresponding to the pedestrian collision is no longer detected by the determination process of step S46, the execution of the circulation process of steps S38 to S46 is terminated. I made it. However, instead of this, the execution of the circulation process in steps S38 to S46 may be terminated after a predetermined time has elapsed since the load distribution pattern corresponding to the pedestrian collision was detected in step S36. In this case, time measurement is started when it is determined as “Yes” in step S36, and the circulation processing of steps S38 to S46 is continued until the measurement time reaches the predetermined time, and the measurement time reaches the predetermined time. Thus, the execution of the circulation process in steps S38 to S46 may be terminated.

  Although one embodiment of the present invention and modifications thereof have been described above, the implementation of the present invention is not limited to the above embodiment and modifications thereof, and various modifications can be made without departing from the object of the present invention. It can be changed.

  For example, in the above embodiment and the modification, in order to correct the temperature of the detection value by the sensor cell 21B, two types of maps representing the relationship between the load and the output voltage (resistance) as shown in FIG. Just prepared. However, instead of this, three or more maps may be prepared corresponding to different temperatures. According to this, by performing the temperature correction calculation using the two maps closest to the detected temperature, it is possible to perform better temperature correction for the detected value of the sensor cell 21B.

  Moreover, in the said embodiment and modification, in the detection of the load distribution pattern corresponding to the pedestrian collision of step S14, S16, step S34, S36 and step S44, S46, the load more than a threshold value is continuing. It was a condition. However, instead of this, the load distribution pattern corresponding to the pedestrian collision is determined based on the shape of the pattern based on the output values of all the sensor cells 21B in which the load is detected in consideration of the load less than the threshold. It may be.

In step S18 of the above embodiment, it is determined whether the sum G1 + G2 of the accelerations G1 and G2 is within a predetermined range. In step S50 of the modification, it is determined whether the sum G1 ′ + G2 ′ of the accelerations G1 ′ and G2 ′ subjected to the low-pass filter processing is within a predetermined range. However, in these determination processes, it is determined whether any one of the accelerations G1 and G2 and any one of the accelerations G1 ′ and G2 ′ subjected to the low-pass filter processing are within a predetermined range. May be. In this case, for example, the larger one of the accelerations G1 and G2 and the accelerations G1 ′ and G2 ′ subjected to low-pass filter processing are used.
The larger value can be adopted.

  Moreover, in the said 1st Embodiment and the modification, it was made to employ | adopt the flip-up of the rear part of the food | hood 11 as a pedestrian protection device ice. However, instead of or in addition to this, as shown by a two-dot chain line in FIG. 1, a hood airbag 18 deployed on the rear portion of the hood 11 can be employed. In this case as well, an ignition control process for deploying the hood airbag 18 may be executed in step S18.

1 is a schematic plan view showing a front portion of a vehicle according to an embodiment of the present invention. (A) is a schematic sectional side view showing a reference state of the hood of the vehicle, and (B) is a schematic sectional side view showing a state in which the hood of the vehicle is flipped up. It is a block diagram of the electric control apparatus for controlling the said vehicle. (A) is a front view of a bumper sensor, (B) is a cross-sectional view showing a mounting state of the bumper sensor, and (C) is a cross-sectional view of each sensor cell of the bumper sensor. It is a graph which shows the characteristic of the load and output voltage (resistance) in the said sensor cell. It is a flowchart of the pedestrian protection program performed by the electronic control unit of FIG. (A) is a figure which shows the example of a pattern of the sensor cell which detected the load more than a threshold value at the time of a vehicle collision, (B) is a figure showing distribution of the detected load of each sensor cell of the example 2 of a pattern in (A). It is a flowchart which shows the modification of the said pedestrian protection program.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Hood, 14, 15 ... Hood actuator, 16 ... Bumper, 18 ... Hood airbag, 21 ... Bumper sensor, 22 ... Temperature sensor, 23, 24 ... Acceleration sensor, 30 ... Electronic control unit

Claims (5)

A pedestrian protection device for protecting the pedestrian when the vehicle collides with the pedestrian,
A plurality of load sensors that are disposed along the vehicle width direction of the bumper and detect a load applied to the bumper at each of the disposed positions;
Pedestrian collision detection means for detecting a collision of a vehicle with a pedestrian based on a distribution pattern of each load detected by each of the plurality of load sensors;
A pedestrian protection device for a vehicle, comprising: an operation control means for activating the pedestrian protection device when a collision with a pedestrian is detected by the pedestrian collision detection means.   The vehicle walking according to claim 1, wherein the pedestrian collision detection means detects a collision of the vehicle with a pedestrian when a load detected by at least two adjacent load sensors is equal to or greater than a predetermined threshold. Protection device.   The pedestrian collision detection means further detects a collision of the vehicle with a pedestrian by further adding a condition that an integrated value of the load detected by the load sensor is within a predetermined range. The pedestrian protection device for a vehicle according to 2. In the pedestrian protection device for a vehicle according to any one of claims 1 to 3,
Temperature detecting means for detecting an environmental temperature in which the plurality of load sensors are disposed;
A pedestrian protection device for a vehicle, comprising temperature correction means for correcting a load detected by the load sensor in accordance with the temperature detected by the temperature detection means. The pedestrian protection device for a vehicle according to any one of claims 1 to 4, further comprising:
An acceleration sensor for detecting the acceleration of the vehicle is provided,
The operation control means further activates the pedestrian protection device on condition that the acceleration detected by the acceleration sensor or a physical quantity related to the acceleration is at least a predetermined value or more. apparatus.

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