Patent ID: 12187212

DETAILED DESCRIPTION OF THE INVENTION

A pedestrian collision determination system according to various embodiments will be described in detail with reference to the accompanying drawings in the following.

FIG.1is a view showing an installation example of a collision detection sensor of a pedestrian collision determination system according to an embodiment of the present invention,FIG.2is an enlarged view of area ‘A’ inFIG.1, andFIG.3is a view showing a cross-section taken along the line B-B′ inFIG.1.

FIGS.1to3show that a collision detection sensor employed in the pedestrian collision determination system according to an embodiment of the present invention may include a conductive pattern disposed on a front surface of a shock absorber110of a vehicle bumper100to form an electromagnetic field by the application of the alternating current power and a conductive material13disposed at a position facing the conductive pattern11on an inner surface of a bumper skin120of the vehicle bumper100.

The bumper100of the vehicle may include the bumper skin120, the shock absorber110, and a bumper back beam130. The bumper skin120is a portion which is exposed to the outside of the vehicle and to which a shock is applied, the shock absorber110is a portion disposed at the rear of the bumper skin120to absorb the shock applied to the bumper skin, and the bumper back beam130may be made of a highly rigid material to serve to disperse the shock applied to the bumper skin120and transmitted to a vehicle body.

Since the structure of the bumper100is already known in the art and the more specific structure of the bumper100is not directly related to the present invention, a more detailed description of the structure of the bumper100will be omitted.

The conductive pattern11may be disposed on the front surface of the shock absorber110and may form an electromagnetic field around it by the application of an alternating current. In particular, the conductive pattern11may have a pattern corresponding to a radiator of an antenna.

More specifically, the conductive pattern11may be implemented as a metal (e.g., gold, silver, copper, etc.) pattern printed on a dielectric film12and form a time-varying electromagnetic field around it by the application of alternating current power of a constant frequency. That is, the conductive pattern11is similar to the radiation pattern of the antenna that forms an electromagnetic wave through the formation of an electromagnetic field so that various types of antenna radiation patterns known in the art may be employed to implement the conductive pattern11.

The dielectric film12printed with the conductive pattern11may be attached to the surface of the shock absorber110using a conventional adhesive means such as a double-sided adhesive tape.

The conductive pattern11may have a band shape extending in the horizontal direction of the vehicle and extend from one end of the surface of the shock absorber110to the other end. Another example is the conductive pattern11that has a band shape extending in the horizontal direction of the vehicle and may be implemented as a plurality of patterns separated from each other at appropriate positions (e.g., three places at the center, right, and left) of the shock absorber110. In this case, the alternating current power may be applied to each of the plurality of conductive patterns11and the current flowing through each may be detected.

The conductive material13may be disposed on an inner surface of the bumper skin120disposed on the front surface of the shock absorber110, that is, at a position facing the conductive pattern11disposed on the shock absorber110. The conductive material13may be manufactured by coating or printing a metal material (e.g., gold, silver, copper) on the inner surface of the bumper skin120.

FIG.4is a cross-sectional view showing an example of bumper deformation when an external shock is applied in a pedestrian collision determination system according to an embodiment of the present invention.

As shown inFIG.4, when an external shock is applied, the conductive material13positioned on the inner surface of the bumper skin120approaches the conductive pattern11and changes the electromagnetic fields formed by the conductive pattern11, which may change the size of the current flowing through the conductive pattern11. More specifically, the size of the current flowing through the conductive pattern before the shock may be determined by impedance characteristics of the current itself. When a bumper skin120deformation generated by a collision causes the conductive material13disposed on the bumper skin120to penetrate a region of an electromagnetic field formed by the conductive pattern11, capacitance and resistance are formed between the conductive pattern11and the conductive material13to change the impedance characteristic so that the current flowing through the conductive pattern changes.

FIG.5is a view showing a state of a conductive pattern before a collision occurs in a pedestrian collision determination system according to an embodiment of the present invention, andFIG.6is a view showing a state between a conductive pattern and a conductive material after a collision occurs in a pedestrian collision determination system according to an embodiment of the present invention.

As shown inFIG.5, when constant alternating current power is applied to the conductive pattern11, a time-varying magnetic field with a constant peak value and time-varying electric field are generated in the conductive pattern before the collision occurs. At this time, the current flowing through the conductive pattern11may be an alternating current with the constant peak value.

When a deformation of the bumper skin120is generated by the collision, as shown inFIG.6, the conductive material13disposed on the bumper skin120penetrates into the region of the electromagnetic field of the conductive pattern11, capacitance Cso and resistance are formed between the conductive pattern11and the conductive material13to change the impedance characteristic.

Here, the conductive pattern11and the conductive material13remain spatially separated before and after the collision so that size of the resistance between the conductive pattern11and the conductive material13remains the same before and after the collision. Accordingly, practically no impedance change of the conductive pattern caused by a resistance change exists at the time of a collision, and only a capacitance change may be considered in an impedance change caused by the collision.

The impedance is proportional to the size of resistance and inversely proportional to the size of capacitance so that the size of the current flowing through the conductive pattern11increases when capacitance is generated between the conductive pattern11and the conductive material13at the time of the collision.

On the other hand, the characteristic of the constant elasticity of the bumper skin120generates the constant vibration at the time of a collision with a pedestrian or other object. This vibration causes the size of the capacitance between the conductive pattern11and the conductive material13to also vibrate, and accordingly, the peak value of the current flowing through the conductive pattern11also vibrates.

It is known in the art that the penetration displacement of the bumper skin with respect to an object collision is proportional to the collision speed and the mass of the colliding object and that the vibration frequency of the bumper skin generated at the time of the collision is proportional to the square root of the stiffness of the colliding object.

Using such characteristics, the pedestrian collision determination system according to an embodiment of the present invention may determine whether the colliding object is a pedestrian using the magnitude of the peak value and the vibration frequency of the peak value of the current flowing in the conductive pattern11.

As described above, the pedestrian collision determination system according to various embodiments of the present invention employs the conductive pattern11and the conductive material13as a means of detecting the pedestrian collision so that the man-hour for installing individual sensor structures on a plurality of bumpers may be significantly reduced, and the sensor itself and additional structures for installing the sensor are not required so that the costs may be significantly reduced.

FIG.7is a block diagram of a pedestrian collision determination system according to an embodiment of the present invention.

FIG.7shows that the pedestrian collision determination system according to an embodiment of the present invention may be configured to include the collision detection sensor10and the control unit20, which may include one or more processors and/or other circuits configured to execute the processes described herein, as described with reference toFIGS.1to6.

The control unit20may determine the mass and the stiffness of the colliding object based on the magnitude of the peak value and the vibration frequency of the peak value of the current flowing in the conductive pattern11and, based on the determination result, may determine whether the colliding object is a pedestrian.

As described above, the penetration displacement of the bumper skin of the colliding object is known to be proportional to the colliding speed and the mass of the colliding object so that the control unit20may deduce the mass of the colliding object using the maximum value of the peak value of the current flowing in the conductive pattern11corresponding to the penetration displacement of the bumper skin and the vehicle speed detected by a vehicle speed detection unit40at the time of the collision.

In addition, the square root of the stiffness of the colliding object is known to be proportional to the vibration frequency of the bumper skin so that the stiffness of the colliding object may be deduced from the vibration frequency of the peak value of the current flowing in the conductive pattern11.

FIG.8is a view showing the types of collision target according to stiffness and mass in a pedestrian collision determination system according to an embodiment of the present invention.

The control unit20may determine the type of the colliding object by applying the criteria shown inFIG.8to the deduced mass and stiffness of the colliding object, and when the colliding object is determined to be a pedestrian, may operate a protection module driving unit50comprising at least one circuit configured to operate a pedestrian protection module such as a hood lift or a pedestrian airbag.

The pedestrian collision determination system according to an embodiment of the present invention may further include a front object detection unit30as an auxiliary means of pedestrian collision determination, and may still further include the protection module driving unit50for driving the pedestrian protection module based on the result of the collision determination.

The front object detection unit30is a sensor detecting a front object of the vehicle and may include a far infrared FIR thermal imaging camera. The front object detection unit30may detect infrared rays emitted from the front object and provide the same to the control unit20.

The protection module driving unit50may drive a protection module for protecting the pedestrian at the time of a collision with a vehicle. Here, the protection module may include at least either of a hood lift and a pedestrian airbag.

The control unit20may determine the front object to be the protection device operation target when the integral value obtained by integrating the infrared intensity of the front object inputted from the FIR thermal imaging camera which is the front object detection unit30and compensated for the outside temperature is equal to or higher than a set intensity. At this time, after separating an animate object from an inanimate object first, the control unit20may differentiate between a child and an adult among the animate objects next.

However, the protection device operation target of the present invention is an adult pedestrian, of whom the intensity of the infrared ray is higher than an inanimate object and a child so that the control unit20may determine the front object to be a protection device operation target when the integral value obtained by integrating the intensity of the infrared ray emitted from the front object is equal to or higher than the set intensity for differentiating an adult pedestrian.

FIG.11is a graph showing by way of an example an output of an infrared thermal imaging camera of a pedestrian collision determination system according to an embodiment of the present invention.

As shown in the left graph inFIG.11, the human body has a higher infrared intensity than other surrounding objects (inanimate objects). In addition, as shown in the center graph inFIG.11, the infrared intensities are different for an adult and a child. Of course, an adult of higher height and larger figure emits higher infrared intensity than a child.

In consideration of this, as shown in the right graph inFIG.11, the control unit20integrates the infrared intensity obtained from the outside front target before the collision, compensates the same for the temperature outside the vehicle, compares the integral value of the infrared intensity with the set reference value, and then, may determine before the collision whether the predicted colliding object is a target of the collision protection device driving when the integral value is larger than the reference value.

Here, the reference value may be set to any value optimized through repeated experiments or simulations.

On the other hand, after determining whether the front object is the protection device operation target, the control unit20determines whether the collision is the protection device operation collision when the front object is determined to be the protection device operation target and may operate the protection module driving unit50when the collision is determined to be the protection device operation collision. That is, after determining the protection device operation target first and sequentially determining the protection device operation collision next, the control unit20may operate the protection module driving unit50.

As described above, the pedestrian collision determination system according to various embodiments of the present invention identifies a pedestrian in the front through an active sensor such as the FIR thermal image camera30, determines whether the pedestrian is a protection device operation target, and when a collision occurs, determines whether the collision is the protection device operation collision through a passive sensor consisting of the conductive pattern11and the conductive material13so that the protection module is only driven in the case of the collision with the protection device operation target, thereby preventing the protection device from malfunctioning and reducing the costs caused by the malfunction.

FIG.9is a flowchart for describing a pedestrian collision determination method according to an embodiment of the present invention.

As shown inFIG.9, in a pedestrian collision determination method according to an embodiment of the present invention, the control unit20receives a detection result from the FIR thermal imaging camera which is the front object detection unit30(S10).

Next, after receiving an input of the detection result from the FIR thermal imaging camera in the step S10, the control unit20may identify the pedestrian target (S20).

In the step S20, the control unit20compares the integral value obtained by integrating the infrared intensity of the front object inputted and compensated for the outside temperature with the set intensity and identifies the pedestrian target. In the present embodiment, the pedestrian target is an adult pedestrian, whose infrared intensity is higher than the infrared intensity of an inanimate object and a child, so the control unit20may compare the integral value obtained by integrating the infrared intensity emitted from the front object with the set intensity for identifying an adult pedestrian and identify the pedestrian target.

Next, the control unit20may determine whether the pedestrian target is the protection device operation target based on the identification result of the pedestrian target in the step S20(S30). When the pedestrian target is identified as an adult, the control unit20may determine the pedestrian target to be the protection device operation target.

On the other hand, the control unit20executes the process of determining the protection device operation target and receives the vehicle speed and the collision detection result from the vehicle speed detection unit40and collision detection sensor10concurrently (S40).

Next, after receiving an input of the collision detection result from the collision detection sensor10in the step of S40, the control unit20may identify the pedestrian collision based on the current change amount and the current amount change pattern, which are the collision detection results (S50).

Here, the control unit20deduces the mass of the colliding object based on the maximum value of the peak value of the current flowing in the conductive pattern11of the collision detection sensor10and the vehicle speed detected by the vehicle speed detection unit40and calculates the stiffness of the colliding object based on the vibration frequency of the peak value of the current flowing in the conductive pattern11, and then, may determine whether the colliding object is a pedestrian (adult) based on the result.

That is, after calculating the mass and the stiffness of the colliding object based on the magnitude and the vibration frequency of the peak value of the current flowing in the conductive pattern11and the vehicle speed, the control unit20may identify the colliding object as an adult pedestrian when the stiffness of the colliding object is included in the set range and the mass is equal to or greater than a set value as shown inFIG.8.

Next, the control unit20may determine whether the collision is a protection device operation collision based on the result of identifying the pedestrian collision in the step S50(S60).

Next, when it is determined in the step S60that the pedestrian collision involves an adult pedestrian, the control unit20may determine the collision to be the protection device operation collision.

Next, according to the determination result of the protection device operation target in the step S30and the determination result of the protection device operation collision in the step S60, the control unit20may determine the collision to be the protection device operation target (S70).

Next, when it is determined in the step S70that the colliding object is the protection device operation target and that the collision is the protection device operation collision, the control unit20may operate the protection module driving unit50(S80).

FIG.10is a flowchart for describing a pedestrian collision determination method according to an embodiment of the present invention.

As shown inFIG.10, in the pedestrian collision determination method according to an embodiment of the present invention, the control unit20may first receive an input of the detection result from the FIR thermal imaging camera which is the front object determination unit30(S110).

Next, after receiving an input of the detection result from the FIR thermal imaging camera in the step S110, the control unit may identify the pedestrian target (S120). The control unit20compares the integral value obtained by integrating the infrared intensity of the front object inputted and compensated for the outside temperature and may identify the pedestrian target in the step S120.

In an embodiment of the present invention, the pedestrian target is an adult pedestrian, and the infrared intensity of the adult pedestrian is higher than the infrared intensity of the inanimate object and child so that the control unit20may compare the integral value obtained by integrating the infrared intensity emitted from the front object with the set intensity for identifying an adult pedestrian and identify the pedestrian target.

Next, the control unit20may determine whether the colliding object is the protection device operation target based on the identification result of the pedestrian target in the step S120(S130). When the pedestrian target is identified as an adult in the step S130, the control unit20may determine the pedestrian target to be the protection device operation target.

Next, when the pedestrian target is determined to be the protection device operation target in the step S130, the control unit20may receive an input of the vehicle speed and the current change of the conductive pattern11, which corresponds to the collision detection result, from the vehicle speed detection unit40and the collision detection sensor10(S140).

Next, after receiving the input of the collision detection result from the collision detection sensor10in the step S140, the control unit20may identify the pedestrian collision based on the current change amount and the current amount change pattern which are the collision detection results (S150).

Here, after calculating the mass of the collision object based on the maximum value of the peak value of the current flowing in the conductive pattern11of the collision detection sensor10and the vehicle speed detected by the vehicle speed detection unit40and calculating the stiffness of the collision object based on the vibration frequency of the peak value of the current flowing in the conductive pattern11, the control unit20may determine whether the collision object is a pedestrian (adult) based on the determination results.

That is, after calculating the mass and the stiffness of the colliding object based on the magnitude and the vibration frequency of the peak value of the current flowing in the conductive pattern11and the vehicle speed, as shown inFIG.8, the control unit20may identify the colliding object as an adult pedestrian when the stiffness of the colliding object is included in the set range and the mass is equal to or greater than a set value.

Next, based on the identification result the pedestrian collision in the step S150, the control unit20may determine whether the pedestrian collision involves the protection device operation target (S160).

Next, when it is determined in the step S160that the pedestrian collision involves an adult pedestrian, the control unit20may determine the collision to involve the protection device operation target.

Next, when the pedestrian collision is determined to be the protection device operation collision in the step S160, the control unit20operates the protection module driving unit50(S170).

As described above, according to the pedestrian determination method according to an embodiment of the present invention, the front pedestrian is identified through the active sensor, whether the pedestrian is the protection device operation target is determined, and when the vehicle collision is detected through the passive sensor, whether the collision is the protection device operation collision is determined so that the protection module is only driven in the case of the protection device operation target, thereby preventing the protection device from malfunctioning and reducing the cost caused by the malfunctioning.

Specific embodiments of the present invention are illustrated and described above, but it will be self-evident to those skilled in the art that the present invention may be improved upon and modified in various ways within the scope not departing from the technical spirit of the present invention provided by the patent claims below.

DESCRIPTION OF REFERENCE NUMERALS

10: collision detection sensor11: conductive pattern12: dielectric film13: conductive material20: control unit30: front object detection unit40: vehicle speed detection unit100: bumper110: shock absorber120: bumper skin130: bumper back beam