Title: Collision determination system
Abstract: A collision determination system of the present invention includes a plurality of acceleration sensors provided in a bumper face of a vehicle for detecting the acceleration of deformation of the bumper face when the vehicle collides with an object. The system also includes an actuation permitter which, even when one of the acceleration sensors detects an acceleration equal to or more than a set value and it is determined that a collision occurs, refers to another acceleration sensor for operation. Under the AND conditions that an actuation permitting signal is supplied from the actuation permitter and a collision detection signal is supplied from a collision detector, an actuating signal output outputs an actuating signal for actuating collision mitigating devices.
Patent Number: 7,024,293 Issued on 04/04/2006 to Ishizaki, et al.
| Inventors:
|
Ishizaki; Tatsuya (Wako, JP);
Matsuda; Kazuo (Wako, JP)
|
| Assignee:
|
Honda Giken Kogyo Kabushiki Kaisha (Minato-ku, JP)
|
| Appl. No.:
|
608676 |
| Filed:
|
June 24, 2003 |
Foreign Application Priority Data
| Jun 25, 2002[JP] | 2002-183964 |
| Jun 25, 2002[JP] | 2002-183998 |
| Current U.S. Class: |
701/45; 701/36; 180/271 |
| Current Intern'l Class: |
B60K 28/14 (20060101); B60R 22/00 (20060101) |
| Field of Search: |
701/45,36
280/728.1,735
180/271,282
340/436
|
References Cited [Referenced By]
U.S. Patent Documents
| 5173614 | Dec., 1992 | Woehrl et al.
| |
| 5737224 | Apr., 1998 | Jeenicke et al.
| |
| 6113138 | Sep., 2000 | Hermann et al.
| |
| 6125313 | Sep., 2000 | Watanabe et al.
| |
| 6216070 | Apr., 2001 | Hayashi et al.
| |
| 6353782 | Mar., 2002 | Kunimi et al.
| |
| 2002/0033755 | Mar., 2002 | Ishizaki et al.
| |
| Foreign Patent Documents |
| 2001080545 | Mar., 2001 | JP.
| |
Primary Examiner: Black; Thomas G.
Assistant Examiner: Tran; Dalena
Attorney, Agent or Firm: Hamre, Schumann, Mueller & Larson, P.C.
Claims
What is claimed is:
1. A collision determination system for detecting a collision of a vehicle with
an object and outputting an actuating signal to collision mitigating devices, said
system comprising:
a plurality of acceleration sensors for mounting to a front portion of said vehicle
to detect accelerations of movement of said front portion in the vehicle longitudinal direction;
an actuation permitting means for outputting an actuation permitting signal for
a fixed time period when one of said acceleration sensors detects an acceleration
equal to or more than a set value within a set time after another acceleration
sensor detects an acceleration equal to or more than the set value, said actuation
permitting means including a plurality of timers, each of said timers being associated
with a respective one of the acceleration sensors, said each of said timers holding
for the set time a signal representing the acceleration detected by the associated
acceleration sensor which is equal to or more than the set value;
a collision detecting means for outputting a collision detection signal when
determining that a collision with a given object occurs based on acceleration detected
by at least one of said acceleration sensors; and
an actuating signal outputting means for outputting an actuating signal to said
collision mitigating devices when receiving both an actuation permitting signal
from said actuation permitting means and a collision detection signal from said
collision detecting means.
2. A collision determination system according to claim 1, wherein a control unit
including said actuation permitting means, collision detecting means and actuating
signal outputting means is mounted in a position different from that of said acceleration sensors.
3. A collision determination system for detecting a collision of a vehicle with
an object and outputting an actuating signal to collision mitigating devices, said
system comprising:
a plurality of acceleration sensors for mounting to a front portion of said vehicle
to detect accelerations of movement of said front portion in the vehicle longitudinal direction;
a plurality of collision detecting means provided in correspondence with said
respective acceleration sensors to perform calculations with said detected accelerations
detected by said acceleration sensors, thereby to detect a collision of said vehicle
with said object;
a plurality of acceleration comparing means provided in correspondence with said
respective acceleration sensors to determine whether or not said detected accelerations
detected by said acceleration sensors are equal to or more than a set value; and
an actuating signal outputting means for outputting an actuating signal when
determining that any of said collision detecting means detects a collision and
any of said acceleration comparing means referring to one of said acceleration
sensors, which is different from the acceleration sensor referred to by said collision
detecting means detecting the collision, has detected an acceleration equal to
or more than the set value during a predetermined past time period before the collision
detection, said acceleration comparing means each including a timer, said each
of said timers holding for the predetermined past time period a signal representing
the acceleration detected by the corresponding acceleration sensor which is equal
to or more than the set value.
4. A collision determination system according to claim 3, wherein said actuating
signal outputting means outputs an actuating signal under such conditions that
any of said collision detecting means detects a collision and the acceleration
comparing means referring to the acceleration sensor mounted adjacent to the acceleration
sensor referred to by said collision detecting means detecting the collision has
detected an acceleration equal to or more than the set value during the predetermined
past time period before the collision detection.
5. A collision determination system according to claim 3, wherein a control unit
including said collision detecting means, acceleration comparing means and actuating
signal outputting means is mounted in a position different from that of said acceleration sensors.
6. A collision determination system for detecting a collision of a vehicle with
an object and outputting an actuating signal to collision mitigating devices, said
system comprising:
a plurality of acceleration sensors for mounting to a front portion of said vehicle
to detect accelerations of movement of said front portion in the vehicle longitudinal direction;
an actuation permitter that outputs an actuation permitting signal for a fixed
time period when one of said acceleration sensors detects an acceleration equal
to or more than a set value within a set time after another acceleration sensor
detects an acceleration equal to or more than the set value, said actuation permitter
including a plurality of timers, each of said timers being associated with a respective
one of the acceleration sensors, said each of said timers holding for the set time
a signal representing the acceleration detected by the associated acceleration
sensor which is equal to or more than the set value;
a collision detector that outputs a collision detection signal when determining
that a collision with a given object occurs based on acceleration detected by at
least one of said acceleration sensors, wherein said collision detector includes
a deformation rate calculator; and
an actuating signal output that outputs an actuating signal to said collision
mitigating devices when receiving both an actuation permitting signal from said
actuation permitter and a collision detection signal from said collision detector.
7. A collision determination system according to claim 6, wherein a control unit
including said actuation permitter, said collision detector and said actuating
signal output is mounted in a position different from that of said acceleration sensors.
8. A collision determination system for detecting a collision of a vehicle with
an object and outputting an actuating signal to collision mitigating devices, said
system comprising:
a plurality of acceleration sensors for mounting to a front portion of said vehicle
to detect accelerations of movement of said front portion in the vehicle longitudinal direction;
a plurality of collision detectors provided in correspondence with said respective
acceleration sensors to perform calculations with said detected accelerations detected
by said acceleration sensors, thereby to detect a collision of said vehicle with
said object, wherein said collision detectors each include a deformation rate calculator;
a plurality of acceleration comparators provided in correspondence with said
respective acceleration sensors to determine whether or not said detected accelerations
detected by said acceleration sensors are equal to or more than a set value; and
an actuating signal output that outputs an actuating signal when determining
that any of said collision detectors detect a collision and any of said acceleration
comparators referring to one of said acceleration sensors, which is different from
the acceleration sensor referred to by said collision detector detecting the collision,
has detected an acceleration equal to or more than the set value during a predetermined
past time period before the collision detection, said acceleration comparators
each including a timer, said each of said timers holding for the predetermined
past time period a signal representing the acceleration detected by the corresponding
acceleration sensor which is equal to or more than the set value.
9. A collision determination system according to claim 8, wherein said actuating
signal output outputs an actuating signal under such conditions that any of said
collision detectors detects a collision and the acceleration comparator referring
to the acceleration sensor mounted adjacent to the acceleration sensor referred
to by said collision detector detecting the collision has detected an acceleration
equal to or more than the set value during the predetermined past time period before
the collision detection.
10. A collision determination system according to claim 8, wherein a control
unit including said collision detectors, said acceleration comparators and said
actuating signal output is mounted in a position different from that of said acceleration sensors.
Description
FIELD OF THE INVENTION
The present invention relates to a collision determination system and, more particularly,
to a collision determination system for detecting a collision of a vehicle with
an object of protection and outputting an actuating signal to hood actuators.
BACKGROUND OF THE INVENTION
As an exemplary conventional art, a collision determination system in a "Vehicle
Hood Actuating System" of Japanese Patent Laid-Open Publication No. 2001-80545
is cited. FIG. 11 is an overall view showing the vehicle hood actuating system
having the collision determination system. In the vehicle hood actuating system,
the collision determination system consists of a speed sensor 501 for detecting
the vehicle speed, an acceleration sensor 503 for detecting an acceleration
acting on a bumper 502 upon a collision of a vehicle 500 with an
object of protection M, a deformation rate calculator 504 for calculating
a bumper deformation rate from the information of acceleration detected by the
acceleration sensor 503, a smoothing processor 505, a speed-threshold
map 506 for varying the threshold of the bumper deformation rate in accordance
with the vehicle speed, a hood actuating device including actuators 508
for holding up the proximal ends of a hood 509 by a predetermined amount,
and an electric control unit (ECU) 507 for controlling the operation of
the actuators 508. When a vehicle speed detected by the speed sensor 501
is a predetermined vehicle speed and a calculated bumper deformation rate exceeds
the threshold, the control unit 507 determines that the collision object
is a predetermined object of protection M and operates the actuators 508
to lift the hood 509 at their proximal ends. The hood actuating device lifts
the hood 509, thereby mitigating the impact of a secondary collision of
the protection object M with the hood 509.
In the above-described collision determination system, if a malfunction occurs
in an acceleration sensing element, electric circuit or the like in the acceleration
sensor 503, an invalid signal (acceleration signal of a great acceleration
as provided upon the occurrence of collision) due to the malfunction may be supplied
from the acceleration sensor 503 though in a no-collision state. Misidentifying
the invalid signal as a normal valid signal, the control unit 507 may determine
that a collision occurs and actuate the hood 509.
Air bag systems have employed a collision determination system having an impact
sensor for sensing an impact of above a certain level provided in a control unit,
which system being configured not to actuate air bags when the impact sensor detects
nothing, even if a collision determination signal is supplied from the control
unit. The impact sensor, however, is provided in the control unit and can only
sense an impact sufficiently large to actuate air bags.
In a collision with an object of as small a weight as a pedestrian as a protection
object of a collision determination system of the present invention, impact occurs
only near a bumper as a colliding area. The impact sensor provided in the control
unit as described above cannot sense a collision with an object of as small a weight
as a pedestrian.
It might be possible to mount the control unit at the front end of a vehicle.
It is, however, difficult to place the control unit in such a narrow space as a
vehicle front end portion. Therefore the above-described impact determination system
for use in air bag systems cannot be used for a collision determination system
for actuating hood actuators, which is the subject matter of the present invention.
Thus desired is a collision determination system having a control unit which
reliably determines whether a vehicle collides with an object and outputs an actuating
signal as appropriate, even when an invalid signal due to a malfunction in an acceleration
sensing element, electrical circuit or the like in an acceleration sensor is supplied.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a collision determination
system for detecting a collision of a vehicle with an object and outputting an
actuating signal to collision mitigating devices, which system comprises: a plurality
of acceleration sensors mountable to a front portion of the vehicle to detect accelerations
of movement of the front portion in the vehicle longitudinal direction; an actuation
permitter for outputting an actuation permitting signal for a fixed time period
when one of the acceleration sensors detects an acceleration equal to or more than
a set value within a set time after another acceleration sensor detects an acceleration
equal to or more than the set value; a collision detector for outputting a collision
detection signal when determining that a collision with a given object occurs based
on acceleration detected by at least one of the acceleration sensors; and an actuating
signal output for outputting an actuating signal to the collision mitigating devices
when receiving both an actuation permitting signal from the actuation permitter
and a collision detection signal from the collision detector.
Thus, in the collision determination system of this invention, even when one
of the acceleration sensors detects an acceleration equal to or more than the set
value by the malfunction of the acceleration sensor and a collision signal is provided,
the output of an actuating signal due to the malfunction of the acceleration sensor
can be prevented by referring to another acceleration sensor.
In the present invention, a control unit including the actuation permitter, collision
detector and actuating signal output is preferably mounted in a position different
from that of the acceleration sensors. Even when an acceleration signal of a large
acceleration as supplied at the occurrence of collision is supplied by the malfunction
of an acceleration sensing element, electric circuit or the like in one of the
acceleration sensors, the control unit provided in a position different from that
of the acceleration sensors can thus reliably detect whether the vehicle collides
with an object and output an actuating signal as appropriate. This is preferable
for collision determination systems for collision mitigating devices because collision
determination systems used in air bag systems and having impact sensors in control
units cannot detect such collisions as causing impacts only near bumpers as colliding
areas, which are the subject of the present invention. Further, limitations on
the mounting position of the control unit can be eliminated.
Further, in the present invention, there is provided a collision determination
system for detecting a collision of a vehicle with an object and outputting an
actuating signal to collision mitigating devices, which system comprises: a plurality
of acceleration sensors mountable to a front portion of the vehicle to detect accelerations
of movement of the front portion in the vehicle longitudinal direction; a plurality
of collision detectors provided in correspondence with the respective acceleration
sensors to perform calculations with the detected accelerations detected by the
acceleration sensors, thereby to detect a collision of the vehicle with the object;
a plurality of acceleration comparators provided in correspondence with the respective
acceleration sensors to determine whether or not the detected accelerations detected
by the acceleration sensors are equal to or more than a set value; and an actuating
signal output for outputting an actuating signal when determining that any of the
collision detectors detects a collision and any of the acceleration comparators
referring to the corresponding acceleration sensor which is different from the
acceleration sensor referred to by the collision detector detecting the collision
has detected an acceleration equal to or more than the set value during a past
time period before the collision detection.
According to the above collision determination system, collision determination
is not made soon after one of the collision detectors referring to the corresponding
acceleration sensor detects a collision, but is made by checking whether the acceleration
of another acceleration sensor has been equal to or more than the set value during
a past time period before the collision detection. Even if an acceleration signal
of a large acceleration as supplied at the occurrence of collision is supplied
by the malfunction of an acceleration sensing element or electric circuit in one
of the acceleration sensors, collision determination is not made when the acceleration
of another acceleration sensor is less than the set value, so that an actuating
signal is not supplied to actuate the collision mitigating devices.
Further in the present invention, the actuating signal output outputs an
actuating signal under such conditions that any of the collision detectors detects
a collision and any of the acceleration comparators referring to the acceleration
sensor mounted adjacent to the acceleration sensor referred to by the collision
detector detecting the collision has detected an acceleration equal to or more
than the set value during a past time period before the collision detection. That
is, an actuating signal is supplied when the acceleration detected by the acceleration
sensor mounted adjacent to the acceleration sensor referred to by the collision
detector detecting the collision is equal to or more than the set value, so that
collision determination is reliably made to actuate the collision mitigating devices.
A control unit including the collision detectors, acceleration comparators and
actuating signal output is preferably mounted in a position different from that
of the acceleration sensors.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will be described in detail
below, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of a vehicle equipped with a collision determination
system according to a first embodiment of the present invention with two acceleration
sensors provided in a vehicle front portion;
FIG. 2 is a cross-sectional view before a collision of a vehicle front end portion
provided with the acceleration sensors;
FIG. 3 is a cross-sectional view during a collision of the vehicle front end
portion provided with the acceleration sensors;
FIG. 4 is an electrical functional block diagram of an ECU in the collision
determination system according to the first embodiment of the present invention;
FIGS. 5A and 5B are flowcharts of the operation of the collision determination
system shown in FIG. 4;
FIG. 6 is a perspective view of a vehicle equipped with a collision determination
system according to a second embodiment of the present invention with three acceleration
sensors provided in a vehicle front portion;
FIG. 7 is an electrical functional block diagram of an ECU in the collision
determination system according to the second embodiment of the present invention;
FIGS. 8A and 8B are flowcharts showing the operation of the collision determination
system according to the second embodiment shown in FIG. 7;
FIG. 9 is an electrical functional block diagram of an ECU in a collision determination
system according to a third embodiment of the present invention;
FIG. 10 is a flowchart of the operation of the collision determination system
according to the third embodiment, corresponding to the flowchart of the second
embodiment shown in FIG. 8B; and
FIG. 11 is an overall view showing a vehicle hood actuating system with a conventional
collision determination system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Initial reference is made to FIGS. 1-5B inclusive, which illustrate a collision
determination system in a first embodiment of the present invention. In a vehicle
front end portion
1 shown in FIG. 1, acceleration sensors
2a and
2b are provided. The acceleration sensors
2a and
2b
are connected to an ECU (electric control unit)
7 mounted in the vehicle.
Any transmission means (such as radio) rather than cables may be used for connection
between the acceleration sensors
2a and
2b and the
ECU
7.
The acceleration sensors
2a and
2b are each configured
in a unit as large as a matchbox, including a well known capacitance-type acceleration
sensing element and electrical circuit. A weight is provided in the acceleration
sensing element. The acceleration sensors
2a and
2b transmit
acceleration signals to the ECU
7 according to detected accelerations due
to a collision.
The ECU
7 outputs an actuating signal to a right actuator
6a
and a left actuator
6b, controlling the actuation. The right
and left actuators
6a and
6b are hood lifting devices.
The right and left actuators
6a and
6b actuate to hold
up the hood
5. FIG. 1 illustrates the hood
5 in a lifted states.
The ECU
7 makes a collision determination based on the received acceleration
signals on acceleration values. When determining that the vehicle front end portion
1 has collided with an object, the ECU
7 actuates the right and left
actuators
6a and
6b to lift the hood
5 to a
predetermined level. As a result, impact in a secondary collision of the object
with the hood
5 is mitigated.
Now, the detection of acceleration due to collision will be described with reference
to FIGS. 2 and 3.
The acceleration sensors
2a and
2b are provided on
the inner surface of a bumper face
3 covering the front of a front bumper
3A at the vehicle front end portion
1. Chain double-dashed lines
in FIG. 3 show the position of the bumper face
3 before collision. When
the bumper face
3 moves rightward in the figure (rearward of the vehicle)
by a collision with an object M, the weights in the acceleration sensing elements
move by inertia in the direction opposite to the direction "a" of acceleration
caused by the movement of the bumper face
3. Variations in capacitance caused
by the movements of the weights are taken by the electric circuits as acceleration values.
The acceleration sensors
2a and
2b detect accelerations
caused by the movement of the bumper face
3 using variations in capacitance
caused by the movements of the weights in the acceleration sensing elements as
described above. The above-described detection of acceleration of the bumper face
3 moving by collision eliminates the need for providing sensors transversely
over the overall length of the bumper face
3 as load sensors for directly
detecting force. Thus in this embodiment, the two acceleration sensors
2a
and
2b are provided transversely at the bumper face
3.
In the first embodiment, the acceleration sensors
2a and
2b
are provided at the bumper face
3 of the vehicle front end portion
1,
which is not limiting. Acceleration sensors may be attached to a bracket deformable
like the bumper face. Alternatively, acceleration sensors may be provided at the
side or rear of a vehicle so as to determine a side collision or a collision from behind.
As shown in FIG. 4, the ECU
7 includes a speed calculator
8, speed
comparator
9, collision detector
23, actuation permitter
24
and actuating signal output
22. The collision detector
23 includes
a first deformation rate calculator
11 and a second deformation rate calculator
12 which receive detected accelerations from the acceleration sensors
2a
and
2b, a first deformation rate comparator
13 and a second
deformation rate comparator
14 for comparing deformation rates calculated
in the first deformation rate calculator
11 and the second deformation rate
calculator
12 with a set value, and a collision detection signal output
15 for outputting a collision detection signal based on the results of comparisons
made by the first deformation rate comparator
13 and the second deformation
rate comparator
14.
The actuation permitter
24 includes a first acceleration comparator
16
and a second acceleration comparator
17 which receive detected accelerations
from the acceleration sensors
2a and
2b, a first timer
18 and a second timer
19 which refer to the first acceleration comparator
16 and the second acceleration comparator
17, a third timer
20
which refers to the first timer
18 and the second timer
19, and an
actuation permitting signal output
21 which refers to the third timer
20.
The actuating signal output
22 receives a collision detection signal supplied
from the collision detection signal output
15 in the collision detector
23 and an actuation permitting signal supplied from the actuation permitting
signal output
21 in the actuation permitter
24.
The speed calculator
8 receives a pulse signal supplied from a speed sensor
4 and calculates the current vehicle speed from the pulse period. The speed
comparator
9 makes a comparison to determine whether the current vehicle
speed is equal to or more than a set speed. When determining that the current vehicle
speed is equal to or more than a set value, the speed comparator
9 transmits
a speed comparison signal to the first and second deformation rate calculators
11 and
12. The first and second deformation rate calculators
11
and
12 having received the speed comparison signal calculate deformation
rates based on detected accelerations transmitted from the right and left acceleration
sensors
2a and
2b, respectively.
The first deformation rate calculator
11 stores detected accelerations
having been supplied from the right acceleration sensor
2a from a
fixed time ago to that moment, and determines the deformation rate by the integration
calculation of the detected accelerations. The second deformation rate calculator
12 stores detected accelerations having been supplied from the left acceleration
sensor
2b from a fixed time ago to that moment, and determines the
deformation rate by the integration calculation of the detected accelerations.
The first deformation rate comparator
13 determines whether or not the
deformation rate calculated by the first deformation rate calculator
11
is equal to or more than the set value, and outputs a deformation rate comparison
signal. Similarly, the second deformation rate comparator
14 determines
whether or not the deformation rate calculated by the second deformation rate calculator
12 is equal to or more than the set value, and outputs a deformation rate
comparison signal. The collision detection signal output
15 outputs a collision
detection signal when receiving a deformation rate comparison signal from either
of the first and second deformation rate comparators
13 and
14.
The first acceleration comparator
16 determines whether or not the detected
acceleration supplied from the right acceleration sensor
2a is equal
to or more than the set value. When determining that the detected acceleration
is equal to or more than the set value, the first acceleration comparator
16
outputs an acceleration comparison signal to the first timer
18. The first
timer
18 starts and then stops at the time when a set time elapses.
The second acceleration comparator
17 determines whether or not the detected
acceleration supplied from the left acceleration sensor
2b is equal
to or more than the set value. When determining that the detected acceleration
is equal to or more than the set value, the second acceleration comparator
17
outputs an acceleration comparison signal to the second timer
19. The second
timer
19 starts and then stops at the time when a set time elapses.
The third timer
20 starts when determining that both the first and second
timers
18 and
19 are in operation, and stops at the time when a set
time elapses. The actuation permitting signal output
21 outputs an actuation
permitting signal for a fixed time period when determining that the third timer
20 is in operation. That is, at the time when either of the right and left
acceleration sensors
2a and
2b detects an acceleration
equal to or greater than the set value while the timer
19 (or
18)
associated with the other acceleration sensor
2b (or
2a)
operates upon the detection of an acceleration equal to or more than the set value
by the acceleration sensor
2b (or
2a), the actuation
permitting signal output
21 outputs an actuation permitting signal for a
fixed time period.
The actuating signal output
22 outputs an actuating signal to the actuators
6a and
6b when receiving both an actuation permitting
signal from the actuation permitting signal output
21 and a collision detection
signal from the collision detection signal output
15.
Now, an operation of the collision determination system according to the first
embodiment of the present invention will be described with reference to flowcharts
shown in FIGS. 5A and 5B.
At the start of operation of the collision determination system, first in step
S
101, various parameters (vehicle speed, deformation rate and flags) for
use in collision determination are initialized.
Detected accelerations supplied from the right and left acceleration sensors
2a and
2b are read (step S
102), and it is determined
whether the detected acceleration of the right acceleration sensor
2a
is equal to or more than the set value (step S
103). When it is determined
that the detected acceleration is equal to or more than the set value, the timer
value of the first timer
18 is reset to start (step S
104) and the
value of a first flag is set at 1 (step S
105).
When it is determined that the detected acceleration is less than the set value
in step S
103, it is checked whether or not the first timer
18 has
already operated (step S
106). When the first timer
18 is in operation,
the process proceeds to step S
108, and when not, the value of the first
flag is set at 0 (step S
107).
Through the operation of steps S
103 to S
107, once the detected
acceleration of the right acceleration sensor
2a becomes equal to
or more than the set value, the value of the first flag is 1 for a fixed time period
even if the detected acceleration then becomes less than the set value during that
period. Specifically, if the value of the first flag is set at 0 after it is once
determined that the detected acceleration of the right acceleration sensor
2a
is equal to or more than the set value, no actuation permitting signal is provided
for actuating the actuators
6a and
6b even when a collision
is detected as described with FIG. 5B. It is thus necessary to maintain the first
flag at 1 within the set time of the first timer
18 to prevent the value
of the first flag from becoming 0 in steps S
106 and S
107. The same
is true for steps S
111 and S
112 and steps S
116 and S
117
to be described below.
Then it is determined whether the detected acceleration supplied from the left
acceleration sensor
2b is equal to or more than the set value (step
S
108). When it is determined that the detected acceleration is equal to
or more than the set value, the timer value of the second timer
19 is reset
to start (step S
109), and the value of a second flag is set at 1 (step S
110).
When the detected acceleration is less than the set value in step S
108,
it is checked whether or not the second timer
19 has already operated (step
S
111). When the second timer
19 is in operation, the process proceeds
to step S
113, and when not, the value of the second flag is set at 0 (step
S
112). Through the operation of steps S
108 to S
112, once the
detected acceleration of the left acceleration sensor
2b becomes
equal to or more than the set value, the value of the second flag is 1 for a fixed
time period even if the detected acceleration then becomes less than the set value
during that period.
Then it is determined whether both of the first and second flags are 1 (step
S
113). When both of the first and second flags are 1, the timer value of
the third timer
20 is reset to start (step S
114), and an actuation
permitting signal is provided (step S
115).
When one of the first and second flags is 0 in step S
113, it is determined
whether the third timer is in operation (step S
116). When the third timer
is in operation, the process proceeds to step S
118, and when not, proceeds
to step S
117. In step S
117, the output of an actuation permitting
signal is stopped. Through the operation of steps S
113 to S
117, once
both of the first and second flags become 1, an actuation permitting signal is
provided for a fixed time period even if either of the first and second flags becomes
0 during that period.
As shown in FIG. 5B, in step S
118, the speed calculator
8 calculates
the current vehicle speed to determine whether the current vehicle speed is equal
to or more than the set value (step S
119). When the current vehicle speed
is equal to or more than the set value, the process proceeds to step S
120.
When the current vehicle speed is less than the set value, the process returns
to step S
102. In step S
120, the deformation rate is calculated based
on the detected accelerations of the right acceleration sensor
2a.
In step S
121, the deformation rate is calculated based on the detected
accelerations of the left acceleration sensor
2b. It is determined
whether at least one of the left and right deformation rates calculated in steps
S
120 and S
121 is equal to or more than the set value (step S
122).
When it is determined that at least one of the left and right deformation rates
is equal to or more than the set value, a collision detection signal is provided
(step S
123). When both of the left and right deformation rates are less
than the set value, the process returns to step S
102.
It is determined whether an actuation permitting signal is provided (step S
124).
When an actuation permitting signal is provided, the actuators
6a and
6b are actuated (step S
125). When no actuation permitting
signal is provided, the process returns to step S
102. When the process proceeds
to step S
125 to actuate the actuators
6a and
6b,
the operation is finished.
The first embodiment has been described with the two acceleration sensors
2a
and
2b. The number of acceleration sensors is not limited to
two and may be three or more.
As described above, according to the collision determination system of the first
embodiment, even when one of a plurality of acceleration sensors outputs by malfunction
an acceleration signal corresponding to acceleration at the occurrence of collision
and a collision detection signal is provided, the output of an actuating signal
due to the malfunction of the acceleration sensor can be prevented by referring
to another acceleration sensor.
Now, a collision determination system according to a second embodiment with
three acceleration sensors provided in a front end portion of a vehicle will be
described with reference to FIGS. 6 to FIGS. 8A and 8B inclusive.
In a vehicle front end portion
201 shown in FIG. 6, acceleration sensors
202a,
202b and
202c are provided. The
acceleration sensors
202a,
202b and
202c
are connected to an ECU (electric control unit)
207 provided within
a passenger compartment. Any means (such as radio) rather than wire cables may
be used for connection between the acceleration sensors
202a,
202b
and
202c and the ECU
207.
The acceleration sensors
202a,
202b and
202c
each have the same configuration as the acceleration sensors described with
FIG. 1. The acceleration sensors
202a,
202b and
202c
transmit acceleration signals to the ECU
207 according to detected accelerations
caused by collision.
The ECU
207 outputs an actuating signal to a right actuator
206a
and a left actuator
206b, controlling the actuation. The right
and left actuators
206a and
206b are hood lifting devices.
The right and left actuators
206a and
206b actuated
lift a hood
205. FIG. 6 shows the hood
205 in a lifted state. The
ECU
207 performs collision determination based on received acceleration
signals on acceleration values, and, when determining that the front end portion
201 of the vehicle has collided with an object, actuates the right and left
actuators
206a and
206b to lift the hood
205
to a predetermined level. As a result, impact in a secondary collision of the object
with the hood
205 is mitigated.
Acceleration comparators and collision detectors associated with the
respective three acceleration sensors
202a,
202b and
202c are provided in the ECU
207.
The mounting of the three acceleration sensors
202a,
202b
and
202c to a bumper and the detection of acceleration are done
in the same manner as in the first embodiment described with FIGS. 2 and 3.
As shown in FIG. 7, the ECU
207 in the second embodiment consists of an
acceleration comparator
210, a collision detector
212, and an actuating
signal output
217.
The acceleration comparator
210 consists of a first acceleration comparator
210a, second acceleration comparator
210b and third
acceleration comparator
210c which receive acceleration signals from
the acceleration sensors
202a,
202b and
202c,
and a first timer
211a, second timer
211b and third
timer
211c paired with the comparators
210a,
210b
and
210c, respectively.
The collision detector
212 has a first collision detector
212a,
second collision detector
212b and third collision detector
212c
which receive acceleration signals for collision detection.
The actuating signal output
217 has a collision determiner
216
and an actuating signal output
217a. The collision determiner
216
consists of a first collision determiner
216a, second collision determiner
216b and third collision determiner
216c. In FIG. 7,
the first acceleration comparator
210a, second acceleration comparator
210b and third acceleration comparator
210c have substantially
the same function. The first timer
211a, second timer
211b
and third timer
211c also have substantially the same function.
The first collision detector
212a, second collision detector
212b
and third collision detector
212c also have substantially the
same function. Thus description will be made below about the operations of the
first acceleration comparator
210a, first timer
211a and
first collision detector
212a.
The first acceleration comparator
210a refers to the first acceleration
sensor
202a to determine whether or not an acceleration detected
by the first acceleration sensor
202a is equal to or more than a
set value. When the comparison shows that the acceleration is equal to or more
than the set value, an acceleration comparison signal is supplied to the first
timer
211a, and the first timer
211a starts. The first
timer
211a stops at the time when a predetermined time elapses after
the start. That is, the first timer
211a is in operation for a predetermined
time period after starting upon the determination of the first acceleration comparator
210a that the acceleration is equal to or more than the set value.
This is for collision determination based on the fact that a collision signal to
be described below is provided during the predetermined time period after an acceleration
equal to or more than the set value is detected.
The second acceleration comparator
210b and third acceleration
comparator
210c and the second timer
211b and third
timer
211c make comparisons and start based on accelerations detected
by the second acceleration sensor
202b and third acceleration sensors
202c, respectively, in the same manner as the first acceleration
comparator
210a and the first timer
211a. The operating
states of the first timer
211a and second timer
211b are
referred to by the third collision determiner
216c. The operating
states of the second timer
211b and third timer
211c are
referred to by the first collision determiner
216a. The operating
states of the first timer
211a and third timer
211c are
referred to by the second collision determiner
216b.
The ECU
207 has a speed calculator
208 which receives a pulse signal
supplied from a speed sensor
204 and calculates the vehicle speed, and a
speed comparator
209 for comparing the calculated vehicle speed with a set speed.
The speed calculator
208 calculates the current vehicle speed from the
pulse period of a pulse signal supplied from the speed sensor
204. The speed
comparator
209 makes a comparison to determine whether or not the current
vehicle speed calculated by the speed calculator
208 is equal to or more
than the set speed, and, when the answer is yes, transmits a speed comparison signal
to the first, second and third collision detectors
212a,
212b
and
212c.
The first, second and third collision detectors
212a,
212b
and
212c use the speed comparison signal on the determination
by the speed comparator
209 that the current vehicle speed is equal to or
more than the set value, for the operation of collision detection based on accelerations
supplied from the first, second and third acceleration sensors
202a,
202b and
202c.
The first collision detector
212a consists of a first deformation
rate calculator
213a, first deformation amount calculator
214a
and first deformation comparator
215a. The second collision detector
212b consists of a second deformation rate calculator
213b,
second deformation amount calculator
214b and second deformation
comparator
215b. The third collision detector
212c consists
of a third deformation rate calculator
213c, third deformation amount
calculator
214c and third deformation comparator
215c.
In a description below, the operation of the first collision detector
212a
will be described.
The first deformation rate calculator
213a stores accelerations
which have been detected by the first acceleration sensor
202a for
a fixed time period, and determines the deformation rate of a bumper face
203
from the value of the integration calculation of the accelerations in the fixed
time period.
The first deformation amount calculator
214a stores deformation
rates of the bumper face
203 which have been calculated by the first deformation
rate calculator
213a for a fixed time period, and determines the
amount of deformation of the bumper face
203 by the integration calculation
of the deformation rates in the fixed time period.
The first deformation comparator
215a compares the deformation
rate calculated by the first deformation rate calculator
213a with
a predetermined deformation rate threshold, and also compares the deformation amount
calculated by the first deformation amount calculator
214a with a
predetermined deformation amount threshold. When both of the deformation rate and
deformation amount are equal to or more than the thresholds, a collision signal
is provided.
The second and third collision detectors
212b and
212c
have the same configuration and component function as the first collision detector
212a, and will not be described. Collision signals supplied from
the first, second and third collision detectors
212a,
212b
and
212c are received by the first, second and third collision
determiners
216a,
216b and
216c, respectively.
The first collision determiner
216a receives a collision signal
supplied from the first collision detector
212a and refers to the
operating states of the second and third timers
211b and
211c.
When determining that either of the second and third timers
211b and
211c is in operation while the collision signal is supplied from
the first collision detector
212a, the first collision determiner
216a outputs a collision determination signal. The actuating signal
output
217a receives the collision determination signal supplied
from the first collision determiner
216a.
The second collision determiner
216b receives a collision signal
supplied from the second collision detector
212b and refers to the
operating states of the first and third timers
211a and
211c.
When determining that either of the first and third timers
211a and
211c is in operation while the collision signal is supplied from
the second collision detector
212b, the second collision determiner
216b outputs a collision determination signal to the actuating signal
output
217a.
The third collision determiner
216c receives a collision signal
supplied from the third collision detector
212c and refers to the
operating states of the first and second timers
211a and
211b.
When determining that either of the first and second timers
211a and
211b is in operation while the collision signal is supplied from
the third collision detector
212c, the third collision determiner
216c outputs a collision determination signal to the actuating signal
output
217a.
The actuating signal output
217a outputs an actuating signal to
the actuators
206a and
206b when receiving a collision
determination signal from any of the first, second and third collision determiners
216a,
216b and
216c.
Now, an operation of the collision determination system in the second embodiment
shown in FIG. 7 will be described with reference to flowcharts shown in FIGS. 8A
and 8B.
At the start of operation of the collision determination system, various parameters
(vehicle speed, deformation rate, deformation amount and the values of flags) for
use in collision determination are first initialized (step S
301). Accelerations
supplied from the acceleration sensors
202a,
202b and
202c are read (step S
302), and then the first acceleration
comparator
210a makes a comparison to determine whether or not the
detected acceleration of the first acceleration sensor
202a is equal
to or more than the set value (step S
303).
When the first acceleration comparator
210a determines that the
detected acceleration of the first acceleration sensor
202a is equal
to or more than the set value, the timer value of the first timer
211a
is reset to start (step S
304) and the value of a first flag is set at
1 (step S
305).
When the first acceleration comparator
210a determines that the
detected acceleration is less than the set value, it is checked whether or not
the first timer
211a is in operation (step S
306). When the
first timer
211a is in operation (the value of the first flag is
1), the process directly proceeds to step S
308. When the first timer
211a
is not in operation, the value of the first flag is turned to 0 (step S
307).
Through the operation of steps S
303 to S
307, once the detected acceleration
of the first acceleration sensor
202a becomes equal to or more than
the set value (the value of the first flag is 1), the value of the first flag is
maintained at 1 for a predetermined fixed time period even if the acceleration
then becomes less than the set value during that period.
In step S
308, the second acceleration comparator
210b makes
a comparison to determine whether or not the detected acceleration is equal to
or more than the set value. When the second acceleration comparator
210b
determines that the acceleration is equal to or more than the set value, the
timer value of the second timer
211b is reset to start (step S
309)
and the value of a second flag is set at 1 (step S
310).
When the second acceleration comparator
210b determines that the
detected acceleration is less than the set value, it is checked whether or not
the second timer
211b is in operation (step S
311). When the
second timer
211b is in operation, the process proceeds to step S
313.
When the second timer
211b is not in operation, the value of the
second flag is turned to 0 (step S
312). Through the operation of steps S
308
to S
312, once the detected acceleration of the second acceleration sensor
202b becomes equal to or more than the set value, the value of the
second flag is maintained at 1 for a fixed time period even if the acceleration
becomes less than the set value during that period.
In step S
313, the third acceleration comparator
210c determines
whether or not the detected acceleration is equal to or more than the set value.
When the third acceleration comparator
210c determines that the acceleration
is equal to or more than the set value, the timer value of the third timer
211c
is reset to start (step S
314) and the value of a third flag is set at
1 (step S
315).
When the third acceleration comparator
210c determines that the
detected acceleration is less than the set value, it is checked whether or not
the third timer
211c is in operation (step S
316). When the
third timer
211c is in operation, the process proceeds to step S
318
shown in FIG. 8B. When the third timer
211c is not in operation,
the value of the third flag is turned to 0 (step S
317). Through the operation
of steps S
313 to S
317, once the detected acceleration of the third
acceleration sensor
202c becomes equal to or more than the set value,
the value of the third flag is maintained at 1 for a fixed time period even if
the acceleration becomes less than the set value during that period.
The speed calculator
208 shown in FIG. 7 calculates the current vehicle
speed from the period of a pulse signal supplied from the speed sensor
204
(step S
318). The speed comparator
209 determines whether or not the
current vehicle speed is equal to or more than the set value (step S
319).
When the current vehicle speed is equal to or more than the set value, the process
proceeds to step S
320.
In step S
320, the first, second and third collision detectors
212a,
212b and
212c each calculate the deformation rate and
the amount of deformation and compare the results with the thresholds. When the
speed comparator
209 determines that the current vehicle speed is less than
the set value, the process returns to step S
302.
When the speed comparator
209 determines that the current vehicle speed
is equal to or more than the set value (step S
319) and the calculations
of the deformation rate and the amount of deformation and the comparisons with
the thresholds are performed (step S
320), the first collision detector
212a
determines whether or not a collision is detected (step S
321). When
the first collision detector
212a determines that a collision is
detected, it is determined whether or not the value of the second flag or third
flag is 1 (step S
322). When it is determined that the value of the second
flag or third flag is 1, that is, it is determined that the second timer
211b
or third timer
211c is in operation, the first collision determiner
216a outputs a collision determination signal (step S
323).
When the first collision detector
212a determines that no collision
is detected, or the second flag and third flag are 0, the process proceeds to step S
324.
In step S
324, the second collision detector
212b determines
whether or not a collision is detected. When the second collision detector
212b
determines that a collision is detected, it is determined whether or not the
value of the first flag or third flag is 1 (step S
325). When it is determined
that the value of the first flag or third flag is 1, that is, it is determined
that the first timer
211a or third timer
211c is in
operation, the second collision determiner
216b outputs a collision
determination signal (step S
326).
When the second collision detector
212
