JP2004322694A - Seat belt device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device for a vehicle capable of controlling a first pretensioner with high accuracy, even when dispersion occurs in a brake pedal stroke and a stroke sensor. <P>SOLUTION: This seat belt device is provided with a brake stroke sensor 20 for detecting a brake operation of the vehicle and a first controller 30 for controlling tension when winding the a webbing by the first pretensioner when the generation of emergency braking is determined based on detected data of the brake pedal stroke sensor 20. The first controller 30 is provided with a means for correcting a zero point position of the brake pedal stroke when it is determined that the brake operation is not performed by the brake pedal stroke sensor 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle seatbelt device having a pretensioner that changes the tension of a webbing, and winding up the webbing when brake braking is predicted to avoid an occupant's risk.
[0002]
[Prior art]
As a technique for avoiding the risk of occupants of a vehicle, for example, a technique described in US Pat. No. 6,370,461 (Patent Document 1) is known. The technique described in Patent Document 1 predicts an inevitable collision and controls the attitude of the vehicle before the collision. Means for predicting an unavoidable collision may be based on a driver's brake operation ratio, an ABS (Anti-lock Break System) operation signal, or obstacle detection by radar.
[0003]
The vehicle attitude control means includes all types of chassis, vehicle bodies, and interior devices. For example, in addition to lowering the vehicle height, changing the position of the steering, changing the position of the seat, and the like, a method of activating the occupant restraint device in advance and changing a threshold value for activating the occupant restraint device can be considered.
[0004]
[Patent Document 1]
US Pat. No. 6,370,461
[Problems to be solved by the invention]
However, in the prior art, the unavoidable collision is predicted by detecting the driver's brake operation ratio, but when the initial position of the brake pedal is shifted, the prediction accuracy is not reduced. I can't. Specifically, when the depression amount of the brake pedal is used for prediction, if the initial position of the brake pedal is shifted, an error is included in the detected depression amount, and the accuracy is reduced.
[0006]
When the stepping speed of the brake pedal is used for prediction, the relationship between the brake pedal stroke and the sensor output value does not become linear depending on the mounting position of the brake pedal and the sensor. Even in such a case, even if the change in the sensor output is the same due to the shift of the initial position, the brake pedal depressing speed differs depending on the range of the brake pedal stroke. Therefore, the prediction accuracy is reduced.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a vehicle seatbelt device including a webbing for restraining an occupant seated on a seat, and a retractor for winding and rewinding the webbing, wherein the webbing is desired for the retractor. A first pretensioner that is driven to take up by tension, a second pretensioner that applies tension to the webbing in an emergency, and finally restrains an occupant; a brake pedal stroke sensor that detects a brake operation of the vehicle; Control means for controlling the tension at the time of winding the webbing by the first pretensioner, when it is determined based on the detection data of the brake pedal stroke sensor that sudden braking has occurred, The first pretensioner is a motorized pretensioner that operates reversibly, and , When the braking operation by said brake pedal stroke sensor is determined to not performed, characterized by comprising means for correcting a zero point position of the brake pedal stroke.
[0008]
【The invention's effect】
According to the present invention, when it is determined that the brake operation is not performed, the brake pedal stroke at that time is set to the zero point of the brake pedal stroke sensor, and the means for correcting the value of the brake pedal stroke sensor is provided. The zero point of the value of the pedal stroke sensor can be corrected, and the operation of the first pretensioner is determined based on the value of the brake pedal stroke sensor, and the accuracy of the control for winding the webbing is improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an arrangement configuration diagram of a seat belt device according to an embodiment of the present invention.
[0010]
As shown in the figure, a seat belt device 10 is shown as an example of a three-point passive seat belt, and a webbing 11 for restraining an occupant H seated on a seat S and one end of the webbing 11 are wound. A retractor 12 is provided. The other end of the webbing 11 is fixed to the vehicle body via an anchor disposed on the door side of the seat S, and a tongue 13 movably inserted through an intermediate portion of the webbing 11 is attached to the seat S. At the center of the vehicle body, detachably engages with a buckle 14 fixed to the vehicle body, and movably supports the webbing 11 between the buckle 14 and the retractor 12 via a through ring 15 above the center pillar Pc. It has become.
[0011]
The retractor 12 includes a first pretensioner 16 that drives the webbing 11 to be wound on or retracted from the retractor 12, and a second pretensioner 16 that applies tension to the webbing 11 in an emergency and finally restrains the occupant H. And a pretensioner 17.
[0012]
The first pretensioner 16 is configured as an electric pretensioner capable of reversible operation, includes a motor M and a reduction gear mechanism 16a, and reduces the number of revolutions of the motor M to provide a webbing that provides torque to the retractor 12. 11 is transmitted to the reel on which it is wound.
[0013]
In this embodiment, the second pretensioner 17 is configured as an explosive type (explosive pretain), and is configured to instantly wind the webbing 11 around the retractor 12 by the explosive force of the explosive upon collision detection.
[0014]
The second pretensioner 17 is not limited to the explosive type, but may be a motor or the like as long as the webbing 11 can be rapidly wound.
[0015]
Further, the retractor 12 is provided with a load force limiter for preventing the tension of the webbing 11 taken up at the time of the collision from rising to a predetermined value or more and imposing a large load on the occupant H, and a sudden withdrawal of the webbing 11. A lock mechanism for sensing and locking the drawer of the webbing 11 is provided.
[0016]
Then, at the time of collision, the occupant's body is restrained by the seat by the lock mechanism, and the second printing tensioner 16 is operated to remove the slack of the webbing 11, thereby improving the restraint of the occupant. Further, the load force limiter acts to suppress the force acting on the occupant's body by the seat belt to a predetermined value or less.
[0017]
Further, the seat belt device 10 according to the present embodiment includes a first controller 30 that controls the first pretensioner 16 and a second controller 53 that controls the second pretensioner 17. .
[0018]
The first controller 30 controls the first pretensioner 16 based on a brake stroke signal detected by a brake pedal stroke sensor 20 for detecting a brake operation amount of the vehicle and a detection signal of a vehicle speed sensor 21.
[0019]
The second controller 53 controls to drive the second pretensioner 17 when a detection signal indicating a collision is given from the shock sensor 52 that detects a shock at the time of a collision.
[0020]
FIG. 2 is a functional block diagram showing a detailed configuration of the first controller 30 (the description of the second controller 53 shown in FIG. 1 is omitted). In the figure, two motors M (M1, M2) of the first pretensioner 16 are provided, of which M1 is for the driver's seat belt device 10, and M2 is for the passenger's seat belt. It is that of the device 10.
[0021]
The first controller 30 includes a CPU 31 as shown in FIG. 2, and further includes a power supply circuit 32 for inputting a power supply voltage from a battery (BATT) via the fuse 22 to the CPU 31 and an IGN (ignition) for inputting an ignition signal. ) An input circuit 33, a CAN (Controller Area Network) I / F 34 for inputting a vehicle speed signal of the vehicle speed sensor 21, and an analog I / F 35 for inputting a brake stroke signal of the brake pedal stroke sensor 20.
[0022]
Here, the voltage stabilized by the power supply circuit 32 is supplied to the brake pedal stroke sensor 20 via the sensor power supply circuit 32a in addition to being used as a drive source of the CPU 31.
[0023]
The control signal output from the CPU 31 is supplied to the relay 37 via the drive circuit 36, and controls the driving of the motors M (M1, M2) for the driver's seat and the passenger's seat and switches the rotation direction. Bridge (H bridge) 38a, 38b.
[0024]
The H-Bridges 38a and 38b are supplied with voltages from the fuse 22 and a battery power supply via a relay 37, and the rotation directions of the motors M are controlled by the H-Bridges 38a and 38b. Is controlled by a duty ratio calculated by the CPU 31 (hereinafter, referred to as a duty).
[0025]
The brake pedal stroke sensor 20 detects the amount of depression of the brake pedal by the driver's braking operation based on the rotation angle of a potentiometer. The brake pedal stroke sensor 20 is connected to a power supply voltage supplied from a sensor power supply circuit 32a. Is converted into a voltage signal corresponding to the amount of depression of the brake pedal, and this voltage signal is output to the CPU 31 via the analog I / F 35.
[0026]
The vehicle speed data detected by the vehicle speed sensor 21 is supplied to the CPU 31 via the CAN I / F 34. In this case, a pulse having a cycle corresponding to the vehicle speed may be output from the vehicle speed sensor 21 without passing through the CAN I / F 34, and the vehicle speed may be detected from the pulse cycle.
[0027]
The CPU 31 determines whether the braking when the brake pedal is depressed is emergency braking based on the detection signal of the brake pedal stroke sensor 20, and determines that it is a collision avoidance operation if it is emergency braking. Then, the current command value is duty-outputted to the H-Bridges 38a, 38b, the rotation speed of the motor M is controlled to apply tension to the webbing 11, and the webbing 11 is wound up.
[0028]
Further, when each of the sensors for detecting the brake pedal stroke and the vehicle speed, which is input to the first controller 30, has a failure, it has a fail-safe function for detecting these failures. Then, the current supply to each motor M (M1, M2) is stopped.
[0029]
FIG. 3 is a functional block diagram showing the configuration of the CPU 31. As shown in the figure, the CPU 31 determines a brake operation determining unit 31 a that determines the operation of the brake based on the detection signal of the brake pedal stroke sensor 20, and determines the end of the braking based on the detection signal of the vehicle speed sensor 21. Braking end determining unit 31b, emergency braking determining unit 31c, fail safe unit 31d, operation mode determining unit 31e, output current to each motor M (M1, M2), and output current for calculating energizing time It includes an energization time calculation unit 31f, a driver seat operation determination unit 31g that determines the operation of the driver seat side motor M1, and a passenger seat operation determination unit 31h that determines the operation of the passenger seat motor M2.
[0030]
Further, a zero-point correcting unit 31i for correcting the zero point of the brake pedal stroke is provided.
[0031]
Next, the operation of the seat belt device 10 according to the embodiment will be described. FIG. 4 is a flowchart showing the overall operation of the seat belt device 10. 5 to 9 are detailed flowcharts.
[0032]
First, the overall operation will be described with reference to FIG. 4. During traveling of the vehicle, the traveling speed of the vehicle detected by the vehicle speed sensor 21 is transmitted to the CPU 31 via the CAN I / F 34 in step S1. It is captured. Next, in step S2, the stroke amount (depressed amount) of the brake pedal detected by the brake pedal stroke sensor 20 is detected, and is taken into the CPU 31 via the analog I / F 35.
[0033]
In step S3, a zero-point correction process of the brake pedal stroke is performed.
[0034]
In step S4, it is determined whether or not emergency braking is performed based on the vehicle speed data and the data on the stroke amount of the brake pedal obtained in the above processing. For example, when an obstacle suddenly appears ahead of the driver while driving or when the obstacle is found late, emergency braking is performed to avoid a collision. Then, based on the output signal of the brake pedal stroke sensor 20, it is detected that an emergency braking operation has occurred.
[0035]
In step S5, it is determined whether the emergency braking has been completed. Here, for example, when the vehicle is stopped, when the speed is substantially constant, or when the vehicle is accelerating, it is determined that the emergency braking is completed.
[0036]
In step S6, a process of calculating the output duty is performed.
[0037]
In step S7, the process of stopping the voltage supply to each motor M is performed by the fail-safe logic when the sensors have failed.
[0038]
In step S8, the operation of the seat belt control is determined based on the fail-safe and operation prohibition conditions, and then the process returns to step S1.
[0039]
Next, the zero-point correction process of the brake pedal stroke shown in step S3 will be described with reference to the flowchart shown in FIG.
[0040]
First, in step S11, it is determined whether the change in the brake pedal stroke is equal to or less than a predetermined value. If it is equal to or smaller than the predetermined value (YES in step S11), it is determined in step S12 whether the brake pedal stroke is equal to or smaller than the predetermined value.
[0041]
If it is equal to or less than the predetermined value (YES in step S12), it is determined in step S13 whether or not this state (a state in which both of steps S11 and S12 are YES) has elapsed for a predetermined time or more. In this case (YES in step S13), in step S14, the value of the detection signal of the brake pedal stroke sensor 20 at this time is set to the zero point of the brake pedal stroke, and a process of correcting the brake pedal stroke is performed in step S15.
[0042]
Further, when the change in the brake pedal stroke is larger than a predetermined value (NO in step S11), when the brake pedal stroke is larger than the predetermined value (NO in step S12), and when the predetermined time does not elapse (NO in step S13). In), since it can be determined that the brake is being operated, the zero point of the brake pedal stroke is not set in step S14, and the process of correcting the brake pedal stroke is performed in step S15.
[0043]
Further, the correction value of the correction processing in step S15 can be obtained as "brake pedal stroke"-"zero point", that is, the difference between the value of the brake pedal stroke and the value set as the zero point.
[0044]
FIG. 6 is a flowchart showing the processing procedure of the emergency braking determination shown in step S4 of FIG. First, in the process of step S21, it is determined whether the vehicle speed is higher than a predetermined speed V1. If it is equal to or lower than V1 (NO in step S21), the control of the webbing tension by the first pretensioner 16 is not performed.
[0045]
If the vehicle speed exceeds V1 (YES in step S21), the brake depression speed is calculated from the output signal of the brake pedal stroke sensor 20 in step S22. In step S23, an expected deceleration G, which is the deceleration G (G indicates acceleration) expected by the driver, is calculated based on the brake depression amount and the brake depression speed.
[0046]
Next, in step S24, the expected deceleration G is compared with the threshold value G1 of the emergency braking determination. If the expected deceleration G is larger than the threshold value G1 of the emergency braking determination (YES in step S24), the emergency braking is performed. Is determined, the emergency braking flag is set to "1" in step S25.
[0047]
FIG. 7 is a flowchart showing the details of the braking judgment termination process in step S5 shown in FIG. In step S31 shown in the figure, it is determined whether the vehicle speed is lower than a predetermined value V0 (for example, V0 is about 5 km / h), and if it is lower than V0 (YES in step S31), the vehicle stops. In step S33, the variable “timer” is incremented.
[0048]
If the vehicle speed is equal to or higher than V0 (NO in step S31), it is determined in step S32 whether the deceleration of the vehicle is smaller than a predetermined deceleration G2, and if it is smaller (YES in step S32). ), It is determined that the vehicle is traveling at a substantially constant speed or that the vehicle is accelerating, and the variable “timer” is incremented in step S34 as in step S33 described above.
[0049]
On the other hand, if the deceleration is equal to or greater than the deceleration G2 (NO in step S32), the "timer" is reset in step S35. That is, the variable “timer” = 0.
[0050]
Thereafter, in step S36, the value of the variable “timer” is compared with a predetermined time T1, and if the “timer” exceeds T1, the emergency braking flag is reset in step S37. That is, when the deceleration has been reduced continuously for the time T1 or more, or when the vehicle has stopped, it is determined that the emergency braking has ended. If the “timer” is equal to or shorter than T1, the emergency braking flag is maintained as it is.
[0051]
Here, the reason why the "timer" waits until the predetermined time T1 is exceeded (the reason why the emergency braking is not immediately terminated) is that although the vehicle is not stopped, the running speed of the vehicle is momentarily lower than V0 due to a tire lock or the like. Or the deceleration becomes momentarily smaller than G2 while being braked by the pumping brake. In such a case, the emergency braking is terminated, and the tension of the webbing 11 is eventually reduced. This is to prevent the control from ending.
[0052]
FIG. 8 is a flowchart showing the output duty calculation process in step S6 shown in FIG. In this process, first, in step S41, it is determined whether the emergency braking flag (see FIG. 6) is “1”. If it is "1" (YES in step S41), the output duty is set to "D1" in step S42, and if it is not "1" (NO in step S41), the output duty is set in step S43. Set the duty to “0”. That is, when the emergency braking flag is “1”, duty output is performed at “D1”, but when “0”, duty output is not performed.
[0053]
FIG. 9 is a flowchart showing a specific processing procedure of the fail-safe processing in step S7 shown in FIG. First, in step S51, it is determined whether a failure has been detected in various sensors or the like. If a failure has been detected, duty output is prohibited in step S53. In other words, when the sensors are out of order, the tension of the webbing 11 may be controlled in spite of the fact that the brake braking or the approach to the obstacle in front is not detected. Since there is a possibility that the occupant may be at risk, in order to avoid this, when a failure is detected, duty output is prohibited.
[0054]
Similarly, in step S52, the duty output is prohibited even when the operation prohibition condition is satisfied. The operation prohibition condition is, for example, a case where it is assumed that the damage is small even if a collision occurs at a low vehicle speed. In such a case, it is desirable to prohibit the output and reduce the operation frequency of the winding of the webbing 11 from the viewpoint of the durability of the motor.
[0055]
On the other hand, if no failure is detected and the operation prohibition condition is not satisfied, duty output is permitted in step S54.
[0056]
By performing the above-described processing, when the emergency braking determination is made, the first pretensioner 16 is operated to apply tension to the webbing 11, thereby suppressing the occupant from moving forward due to the inertial force during deceleration. Even if the vehicle collides with an obstacle as it is, the possibility of a secondary collision in the vehicle interior can be reduced as much as possible.
[0057]
Next, the zero point setting process in step S14 shown in FIG. 5 will be described in detail. As shown in FIGS. 10 and 11, the output of the brake pedal stroke sensor 20 with respect to the brake pedal stroke is offset due to play, deformation, and electrical characteristics of the mounting portion, and a zero point shift may occur.
[0058]
For example, when the sensor output for the change in the brake pedal stroke is set to change as shown by a straight line P1 in FIG. 12, but an offset occurs and changes as shown by a straight line P2, It operates when the brake pedal stroke exceeds S1, despite the setting that the seat belt control is started when the brake pedal stroke exceeds the value S2 set as the threshold value. Malfunctions.
[0059]
As a result, as shown by the curve P3 in FIG. 13, when the zero point is correctly determined, even if the braking operation is not determined to be the emergency braking, the zero point shift occurs, and the sensor output becomes the curve. As shown in P4, the threshold value Th1 is exceeded, and it is determined that the emergency braking is performed, and the seat belt control is started. Therefore, the operation frequency increases, and the occupant feels troublesome.
[0060]
In the present embodiment, a state in which the brake pedal stroke is not operated is determined, and a zero point is set based on the brake pedal stroke position at this time, thereby removing backlash, deformation, and offset due to electrical characteristics. And solves the above problem.
[0061]
Here, the zero point shift is an error of the sensor output with respect to the absolute value of the brake pedal stroke, but since the inclination of the sensor output with respect to the brake pedal stroke is equal, the brake pedal stroke speed obtained by differentiating the brake pedal stroke is obtained. There is no error. Therefore, when emergency braking is determined using the brake pedal stroke and the brake pedal stroke speed, only the error of the brake pedal stroke needs to be considered.
[0062]
In this manner, in the vehicle seat belt device according to the first embodiment, when it is determined that the brake operation is not performed, the brake pedal stroke at that time is set to the zero point of the brake pedal stroke sensor, and the brake pedal stroke is determined. Since the means for correcting the value of the sensor is provided, the zero point of the value of the brake pedal stroke sensor can be corrected, and the operation of the first pretensioner is determined based on the value of the brake pedal stroke sensor. The accuracy of the control for winding the webbing 11 is improved. Thereby, the tension control of the webbing 11 can be performed with high accuracy.
[0063]
In addition, the condition for determining that the brake operation is not performed is such that the state where the change in the brake pedal stroke is within a predetermined value has continued for a predetermined time or more, and the state where the value of the brake pedal stroke is within a predetermined range has continued for a predetermined time or more. Since the case has been made, it can be reliably determined that the brake operation is not being performed.
[0064]
Further, since the correction value is a difference between the brake pedal stroke and the zero point of the brake pedal stroke, the zero point of the value of the brake pedal stroke sensor can be corrected with high accuracy.
[0065]
Next, a seat belt device according to a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the processing procedure for zero-point correction of the brake pedal stroke shown in FIG. 5 and is otherwise the same as the first embodiment. Only this processing procedure will be described.
[0066]
FIG. 14 is a flowchart illustrating a processing procedure for zero-point correction of a brake pedal stroke according to the second embodiment.
[0067]
As shown in the figure, first, in step S61, it is determined whether or not the zero point of the brake pedal stroke has not been set. If it has not been set (YES in step S61), it is determined in step S62 whether the change in the brake pedal stroke is equal to or less than a predetermined value. If it is equal to or smaller than the predetermined value (YES in step S62), it is determined in step S63 whether the brake pedal stroke is equal to or smaller than the predetermined value.
[0068]
If it is equal to or less than the predetermined value (YES in step S63), it is determined in step S64 whether this state has elapsed for a predetermined time or more. If it has elapsed for a predetermined time (YES in step S64), step S65 is performed. Then, the value of the detection signal of the brake pedal stroke sensor 20 at this time is set to the zero point of the brake pedal stroke, and processing for correcting the brake pedal stroke is performed in step S66.
[0069]
When the zero point of the brake pedal stroke is set (NO in step S61), when the change in the brake pedal stroke is larger than a predetermined value (NO in step S62), when the brake pedal stroke is larger than the predetermined value If (NO in step S63) and the predetermined time has not elapsed (NO in step S64), the process of correcting the brake pedal stroke is performed in step S66 without setting the zero point of the brake pedal stroke in step S65. Do.
[0070]
That is, in the present embodiment, only when the zero point of the brake pedal stroke has not been set, the change in the brake pedal stroke is within the predetermined value and the state where the brake pedal stroke is equal to or less than the predetermined value continues for a predetermined time or more. Then, the brake pedal stroke at that time is set to the zero point, and the zero point is corrected.
[0071]
Therefore, once the above condition is satisfied and the zero point is set, the zero point is not set again. This is because the zero point of the brake pedal shifts due to backlash, deformation, and electrical characteristics of the mounting portion, and a large shift of the zero point does not frequently occur. If the zero point of the brake pedal stroke has not been set, zero point correction may be performed using “0” as the initial value of the zero point.
[0072]
Also, the zero point correction may be performed once when the ignition is turned on.
[0073]
In this manner, in the vehicle seatbelt device according to the second embodiment, the process of correcting the zero point position of the brake pedal stroke is performed only when the zero point has not been set. Can be prevented.
[0074]
Also, during the same ignition, the zero point position is corrected only once, so that the zero point correction is not performed frequently, and the first pretensioner based on the value of the brake pedal stroke sensor is used. There is no variation in the operation determination of the screw.
[0075]
Next, a third embodiment of the present invention will be described. In the third embodiment, the fail-safe process shown in FIG. 9 of the first embodiment is changed to the process shown in the flowchart of FIG. 15, and other configurations are the same as those of the first embodiment. It is.
[0076]
First, in step S71, it is determined whether a failure has been detected in various sensors or the like. If a failure has been detected, duty output is prohibited in step S74. In other words, when the sensors are out of order, the tension of the webbing 11 may be controlled in spite of the fact that the brake braking or the approach to the obstacle in front is not detected. Since there is a possibility that the occupant may be at risk, in order to avoid this, when a failure is detected, duty output is prohibited.
[0077]
In step S72, the duty output is prohibited even when the operation prohibition condition is satisfied. Further, when it is determined in step S73 that the zero point of the brake pedal stroke has not been set, the duty output is similarly prohibited in step S74. The operation prohibition condition is, for example, a case where it is assumed that the damage is small even if a collision occurs at a low vehicle speed. In such a case, it is desirable to prohibit the output and reduce the operation frequency of the winding of the webbing 11 from the viewpoint of the durability of the motor.
[0078]
On the other hand, if no failure is detected, the operation prohibition condition is not satisfied, and the zero point of the brake pedal stroke is set, duty output is permitted in step S75.
[0079]
Therefore, after turning on the ignition, the webbing 11 is not wound up until the change in the brake pedal stroke is within the predetermined value and the state in which the brake pedal stroke is equal to or less than the predetermined value continues for the predetermined time or more. . Thereby, even if the deviation of the zero point is large, the webbing 11 is not taken up until the zero point is corrected, so that the webbing 11 is taken up during a braking operation that cannot be said to be an emergency brake. Can be prevented.
[0080]
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the output duty calculation process shown in FIG. 8 of the first embodiment is changed to the process shown in the flowchart of FIG. 16. Other configurations are the same as those of the first embodiment. Identical.
[0081]
First, in step S81, it is determined whether or not the emergency braking flag is "1". If it is "1" (YES in step S81), in step S82, the zero point of the brake pedal stroke is not set. It is determined whether there is. If it has not been set (YES in step S82), the output duty is set to "D1" in step S83.
[0082]
If the zero point of the brake pedal stroke has been set (NO in step S82), the output duty is set to "D2" (where D2> D1) in step S84. If the emergency braking flag is not "1" (NO in step S81), the output duty is set to "0" in step S85.
[0083]
In this process, when the zero point of the brake pedal stroke is not set, the output duty is set lower than when the zero point is set. As a result, in the state where the zero point of the brake pedal stroke is shifted and the zero point is not corrected, the first pretensioner 16 is operated in spite of a brake operation that cannot be said to be an emergency brake. Even if the operation threshold value is exceeded, the tension for winding the webbing 11 is set to be relatively low, so that the occupant is less likely to feel uncomfortable.
[0084]
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the zero-point correction process of the brake pedal stroke shown in FIG. 5 of the first embodiment is changed to the process shown in the flowchart of FIG. 17. This is the same as the embodiment. In FIG. 1, a detection signal of a brake lamp switch (not shown) is input to the first controller 30.
[0085]
In FIG. 17, first, in a step S91, it is determined whether or not the brake lamp switch is turned on. If the brake lamp switch is on (YES in step S91), a zero point of the brake pedal stroke is set in step S92.
[0086]
Next, in step S93, a zero point correction of the brake pedal stroke is performed. If the brake lamp switch is off (NO in step S91), a process of correcting the brake pedal stroke is performed in step S93 without setting the zero point of the brake pedal stroke.
[0087]
In this process, the point at which the brake lamp switch is turned on is set as the zero point of the brake pedal stroke sensor, and the brake pedal stroke is corrected. Since the brake lamp switch is always turned on when the brake is depressed, the zero point correction is always performed when the brake is depressed.
[0088]
As described above, in the vehicle seat belt device according to the fifth embodiment, the value of the brake pedal stroke sensor is corrected by setting the point at which the brake lamp switch is turned on to the zero point of the brake pedal stroke sensor. Therefore, when the brake operation is performed, the zero point correction is always performed, and the zero point shift of the brake pedal stroke sensor eliminates the dispersion of the operation determination of the first pretensioner based on the value of the brake pedal stroke sensor. .
[0089]
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, the zero-point correction process of the brake pedal stroke shown in FIG. 5 of the first embodiment is changed to the process shown in the flowchart of FIG. 18, and other configurations are the same as those of the first embodiment. This is the same as the embodiment. In FIG. 1, the first controller 30 is configured to receive a detection signal of an accelerator pedal stroke sensor (not shown).
[0090]
In FIG. 18, first, in step S101, it is determined whether the change in the brake pedal stroke is equal to or less than a predetermined value. If it is equal to or smaller than the predetermined value (YES in step S101), it is determined in step S102 whether the brake pedal stroke is equal to or smaller than the predetermined value.
[0091]
If it is equal to or less than the predetermined value (YES in step S102), it is determined in step S103 whether this state has elapsed for a predetermined time or more. If it has elapsed for a predetermined time (YES in step S103), step S104 is performed. It is determined whether or not the change in the accelerator pedal stroke is equal to or greater than a predetermined value. If the accelerator pedal stroke is equal to or larger than the predetermined value (YES in step S104), the value of the detection signal of the brake pedal stroke sensor 20 at this time is set to a zero point of the brake pedal stroke in step S105, and the brake is moved in step S106. A process for correcting the pedal stroke is performed.
[0092]
When the change in the brake pedal stroke is larger than a predetermined value (NO in step S101), when the brake pedal stroke is larger than the predetermined value (NO in step S102), and when the predetermined time has not elapsed (NO in step S103). If the accelerator pedal stroke is smaller than the predetermined value (NO in step S104), there is a possibility that the brake operation is currently being performed. Therefore, the zero point of the brake pedal stroke is not set in step S105, and step S106 is not performed. Then, the brake pedal stroke is corrected.
[0093]
In this process, when the change in the brake pedal stroke is within a predetermined value and the state in which the brake pedal stroke is equal to or smaller than the predetermined value continues for a predetermined time or more, if the accelerator pedal operation is performed, the brake at that time is The value of the pedal stroke sensor is set as the zero point of the brake pedal stroke, and the zero point is corrected. Thereby, it is possible to more reliably determine that the brake operation is not being performed and set the zero point.
[0094]
In this manner, in the vehicle seat belt device according to the sixth embodiment, when the operation of the accelerator pedal is detected, the value of the brake pedal stroke sensor at that time is corrected as the zero point of the brake pedal stroke sensor. Is performed, it is possible to reliably determine that the brake operation is not being performed.
[0095]
Next, a seventh embodiment of the present invention will be described. In the seventh embodiment, the zero-point correction process of the brake pedal stroke shown in FIG. 5 of the first embodiment is changed to the process shown in the flowchart of FIG. 19, and the other configurations are the same as those of the first embodiment. This is the same as the embodiment.
[0096]
In FIG. 19, first, in step S111, it is determined whether or not the change in the brake pedal stroke is equal to or less than a predetermined value. If it is equal to or smaller than the predetermined value (YES in step S111), it is determined in step S112 whether the brake pedal stroke is equal to or smaller than the predetermined value.
[0097]
If it is equal to or less than the predetermined value (YES in step S112), it is determined in step S113 whether this state has elapsed for a predetermined time or more. If it has elapsed for a predetermined time or more (YES in step S113), step S115 Then, the value of the detection signal of the brake pedal stroke sensor 20 at this time is set as the zero point of the brake pedal stroke, and in step S117, processing for correcting the brake pedal stroke is performed.
[0098]
When the change in the brake pedal stroke is larger than a predetermined value (NO in step S111), when the brake pedal stroke is larger than the predetermined value (NO in step S112), and when the predetermined time does not elapse (NO in step S113). In step S114, it is determined whether the zero point of the brake pedal stroke has not been set.
[0099]
If it has not been set (YES in step S114), the zero point of the brake pedal stroke is set to an initial value in step S116, and then the brake pedal stroke is corrected in step S117. If not set (NO in step S114), the brake pedal stroke is corrected in step S117 without setting the zero point of the brake pedal stroke in steps S115 and S116.
[0100]
In this process, the brake pedal is not operated until the zero point of the brake pedal is not set, that is, until it is determined that the brake pedal is not operated (until “YES” in step S113). A non-zero value is used as the initial value of the zero point.
[0101]
Here, as shown in FIG. 20, the initial value (the initial value used in step S116) is the first pretensioner 16 within the range of the deviation of the brake pedal stroke sensor value from the actual brake pedal stroke. Is used as the initial value of the zero point of the brake pedal stroke.
[0102]
That is, as shown in FIG. 20A, there is a variation in the brake pedal stroke, and the deceleration G predicted from the brake pedal stroke is, for example, 0.6 when the threshold value is 0.7. It varies in the range of ~ 0.8. That is, this range is the width of the estimated deceleration G deviation.
[0103]
In the present embodiment, as described above, the offset value at which the sensitivity of the operation determination of the first pretensioner 16 becomes the weakest is used as the initial value of the zero point of the brake pedal stroke. A width of 7 (ie, 0.1) is used as the value of the zero point offset. That is, the deceleration G predicted from the brake pedal stroke is in the range of 0.7 to 0.9 as shown in FIG. 20B by adding 0.1, and the first pretensioner 16 The sensitivity at the time of operation is set so as to be low.
[0104]
In this way, in the seventh embodiment, the sensitivity at the time of operating the first pretensioner 16 is set to be low until the zero point shift is corrected, so that the operation frequency does not increase. The occupant will not be bothered.
[0105]
That is, the lower limit of the threshold value for determining the operation of the first pretensioner based on the value of the brake pedal stroke sensor during the period until the zero point correction is performed falls within the allowable range of the operation variation. The frequency of taking is not increased, and the occupant is not bothered.
[0106]
Next, an eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment is an example in which, in the above-described seventh embodiment, as an initial value of the zero point of the brake pedal, an allowable width is considered in the threshold value for the seat belt operation determination.
[0107]
Here, the difference between the maximum value of the deviation width of the brake pedal stroke sensor value with respect to the actual brake pedal stroke and the allowable width of the operation determination of the first pretensioner 16 is equal to the first pretensioner 16. The initial value of the zero point of the brake pedal stroke is set so that the sensitivity of the operation determination of (1) becomes dull.
[0108]
That is, as shown in FIG. 21A, when the allowable range of the variation of the deceleration G predicted from the brake pedal stroke is in the range of, for example, 0.6 to 0.8, in addition to this, Since there is an allowable width (here, 0.05) for determining the operation of one pretensioner 16, the sum of these is the maximum width of the deviation. Here, the maximum width of the deviation is 0.55 to 0.85.
[0109]
In this embodiment, the allowable width 0.05 is used as an initial value of the zero point offset. That is, as shown in FIG. 3B, the maximum width of the deviation is set, so that the sensitivity at the time of operating the first pretensioner 16 is set to be low.
[0110]
Accordingly, even when the zero point correction of the brake pedal stroke sensor is not performed, the lower limit of the displacement of the brake pedal stroke sensor falls within the allowable range for determining the operation of the first pretensioner 16, and the webbing 11 is frequently tightened. , So that the occupant is not bothered.
[0111]
That is, in the vehicle seatbelt device according to the eighth embodiment, the brake pedal stroke sensor value is a value within the range of a possible error, and the error value at which the sensitivity of the determination based on the brake stroke becomes the weakest, and the brake stroke Since the difference between the judgment error and the allowable minimum value is used as the initial value of the zero point, the frequency of winding the webbing 11 does not increase and the occupant is not bothered. Further, since the allowable range of the threshold value for the operation determination is considered, the accuracy of the operation determination until the zero point correction is performed is improved as compared with the case where the allowable range is not considered.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a vehicle equipped with a vehicle seatbelt device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a first controller and devices attached thereto.
FIG. 3 is a functional block diagram illustrating processing in a CPU.
FIG. 4 is a flowchart showing overall processing of each embodiment according to the present invention.
FIG. 5 is a flowchart illustrating a procedure of a zero-point correction process of a brake pedal stroke according to the first embodiment.
FIG. 6 is a flowchart illustrating a procedure of an emergency braking determination process according to the first embodiment.
FIG. 7 is a flowchart illustrating a procedure of an emergency braking end determination process according to the first embodiment.
FIG. 8 is a flowchart illustrating a procedure of a process of calculating an output duty according to the first embodiment.
FIG. 9 is a flowchart illustrating a fail-safe processing procedure according to the first embodiment.
FIG. 10 is an explanatory diagram showing assembly variations occurring in a brake pedal.
FIG. 11 is a characteristic diagram illustrating a relationship between a change in a brake pedal stroke and a sensor output, and illustrates a case where a variation occurs in a brake pedal stroke or a stroke sensor.
FIG. 12 is an explanatory diagram showing a deviation of a threshold value caused by a zero point deviation of a brake pedal stroke.
FIG. 13 is an explanatory diagram showing an error of a sensor output caused by a zero point shift of a brake pedal stroke.
FIG. 14 is a flowchart illustrating a procedure of a zero-point correction process of a brake pedal stroke according to the second embodiment.
FIG. 15 is a flowchart illustrating a fail-safe processing procedure according to the third embodiment.
FIG. 16 is a flowchart illustrating a procedure of a process of calculating an output duty according to the fourth embodiment.
FIG. 17 is a flowchart illustrating a procedure of a zero-point correction process of a brake pedal stroke according to the fifth embodiment.
FIG. 18 is a flowchart illustrating a procedure of a zero-point correction process of a brake pedal stroke according to the sixth embodiment.
FIG. 19 is a flowchart showing a procedure of a zero-point correction process of a brake pedal stroke according to the seventh embodiment.
FIG. 20 is an explanatory diagram illustrating a method of correcting a zero point shift according to the seventh embodiment.
FIG. 21 is an explanatory diagram showing a method of correcting a zero point shift according to the eighth embodiment.
[Explanation of symbols]
Reference Signs List 10 seat belt device 11 webbing 12 retractor 13 tongue 14 buckle 15 through ring 16 first pretensioner 16a reduction gear mechanism 17 second pretensioner 20 brake pedal stroke sensor 21 vehicle speed sensor 22 fuse 30 first controller (control means)
31 CPU
31a Brake operation determination unit 31b Braking end determination unit 31c Emergency braking determination unit 31d Fail safe unit 31e Operation mode determination unit 31f Output current and conduction time calculation unit 31g Driver seat operation determination unit 31h Passenger seat operation determination unit 31i Zero point correction unit 32 Power supply circuit 32a Sensor power supply circuit 33 IGN input circuit 34 CAN I / F
35 Analog I / F
36 Drive circuit 37 Relay 38a, 38b H-Bridge
52 Impact sensor 53 Second controller

Claims (11)

In a vehicle seatbelt device including a webbing for restraining an occupant seated on a seat and a retractor for winding and rewinding the webbing,
A first pretensioner that winds and drives the webbing on the retractor with a desired tension;
A second pretensioner that tensions the webbing in an emergency and ultimately restrains an occupant;
A brake pedal stroke sensor that detects a brake operation of the vehicle,
Control means for controlling the tension at the time of winding the webbing by the first pretensioner, when it is determined based on the detection data of the brake pedal stroke sensor that sudden braking has occurred,
The first pretensioner is an electric pretensioner that operates reversibly,
A vehicle seat belt comprising: means for correcting a zero point position of a brake pedal stroke when the brake pedal stroke sensor determines that a brake operation is not performed, wherein the control means includes: apparatus. The condition for determining that the brake operation has not been performed is that a change in the brake pedal stroke is equal to or less than a predetermined value, and that a state in which the brake pedal stroke value is equal to or less than a predetermined value has elapsed for a predetermined time or more. The vehicle seatbelt device according to claim 1, wherein: 3. The vehicle seat belt according to claim 1, wherein a correction value for correcting the zero point position is obtained as a difference between a brake pedal stroke and a zero point of the brake pedal stroke. apparatus. The vehicle seat belt device according to any one of claims 1 to 3, wherein the process of correcting the zero point position of the brake pedal stroke is performed only when the zero point has not been set. The vehicle seat belt device according to any one of claims 1 to 4, wherein the process of correcting the zero point position of the brake pedal stroke sensor is performed only once while the same ignition is turned on. . When the operation condition of the first pretensioner based on the detection data of the brake pedal stroke sensor is satisfied until the process of correcting the zero point position of the brake pedal stroke sensor is performed after the ignition is turned on. The vehicle seatbelt device according to any one of claims 1 to 5, wherein the first pretensioner is not operated even in the case. Using the detection data of the brake pedal stroke sensor, in the case where the first pretensioner operating condition is satisfied, and after the ignition is turned on, until the zero point correction of the brake pedal stroke sensor is performed, The vehicle seat belt according to any one of claims 1 to 5, wherein the tension generated by the first pretensioner is set to a lower value than after the zero point correction is performed. apparatus. The detection data of the brake pedal stroke sensor is corrected using the brake pedal stroke position at which a brake lamp switch mounted on the vehicle is turned on as a zero point of the brake pedal stroke sensor. The vehicle seatbelt device according to any one of claims 3 to 5. When an operation of an accelerator pedal mounted on a vehicle is detected, correction is performed by using detection data of a brake pedal stroke sensor at that time as a zero point of a brake pedal stroke. The vehicle seatbelt device according to any one of claims 3 to 6. An error value of the detection data of the brake pedal stroke sensor, which is within a range of a possible error and at which the sensitivity of the determination based on the brake stroke becomes the weakest, is used as an initial value of a zero point. The vehicle seatbelt device according to claim 9. The difference between the error value at which the sensitivity of the judgment based on the brake stroke is the lowest and the allowable minimum value of the judgment error based on the brake stroke, which is a value within the range of possible errors of the detection data of the brake pedal stroke sensor, is zero. The vehicle seat belt device according to any one of claims 1 to 9, wherein the vehicle seat belt device is used as an initial value of a point.

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