JP2008143275A - Seat belt winding control device, seat belt winding device, seat belt winding control method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adequately execute the seat belt winding operation even when the efficiency of the seat belt winding operation by a motor is degraded. <P>SOLUTION: A control parameter set value table 201 stores the set value of the control parameters for controlling a motor for each changing stage to indicate the stage in which the operational efficiency of a retractor is degraded. A set value changing condition table 202 stores set value changing conditions of the control parameters for each changing stage. A degradation information acquisition unit 301 acquires degradation information of the retractor such as the number of winding operations or the like. A set value change discrimination unit 302 refers to the set value changing condition table 202, and reads out the changing stage of the conditions if the degradation information satisfies the set value changing condition. A set value changing unit 303 validates the set value of the read-out changing stage among the set values stored in the control parameter set value table 201. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seat belt winding control device, a seat belt winding device, a seat belt winding control method, and a program that control the winding of a seat belt.

  A seat (seat) of a vehicle such as an automobile is provided with a seat belt (seat belt) device for holding an occupant in the seat. This seat belt device includes a belt (webbing), a buckle, a tongue plate, a retractor, and the like.

  Among these, the retractor is a device (seat belt retractor) for winding the belt. The retractor includes a pretensioner that restrains the occupant to the seat by moving the piston and pulling the belt strongly by an explosive explosion or the like in an emergency such as a vehicle collision in addition to a winding mechanism using a spring force. Furthermore, in recent years, there is a motor retractor that includes a motor and can wind the belt by the motor.

  In the motor retractor, in order to reduce power consumption, power is supplied to the motor when the belt is wound, and when the winding is completed, the supply of power to the motor is stopped and the motor is stopped. However, for example, even when the belt is being wound, if the belt gets caught on the occupant's arm, etc., or if the occupant begins to pull out the belt during winding, the motor is stopped and then The motor should be controlled.

Assuming such a case, a motor retractor that can appropriately handle both the seat belt catching and the occupant pulling out of the seat belt during winding without using a special sensor. There is an invention (see, for example, Patent Document 1). Specifically, the motor retractor described in Patent Document 1 stops the winding and waits for a predetermined time when an overload is detected during the seat belt winding, and after the predetermined time elapses, the motor retractor is wound again. Take action to take.
JP 2005-280497 A

  By the way, the motor retractor may have a lower operating efficiency due to aged deterioration of the motor and the mechanism. In this case, the power transmission loss in the motor and the mechanism increases, and the value of the motor current at the time of winding the seat belt increases. May rise. In such a case, if overload is detected based on a predetermined current value using the invention of the above-mentioned Patent Document 1, catching or the like is appropriately judged before deterioration and winding is temporarily interrupted. However, after the deterioration, although it was a normal seat belt winding, it was judged that the belt was caught and the winding could be stopped.

  In the motor retractor, the seat belt retracting speed is controlled by voltage. Therefore, when the power transmission loss in the motor or the mechanism portion increases due to aging deterioration, there is a concern that the winding speed may be reduced even if the voltage value is the same as that before the deterioration.

  The present invention has been made in view of the above-described situation, and even when the efficiency of the seat belt retracting operation by the motor is reduced, the seat belt retracting operation can be appropriately performed. It is an object to provide a control device, a seat belt retractor, a seat belt retract control method, and a program.

In order to achieve the above object, a seat belt retractor according to the first aspect of the present invention includes:
Motor control value storage means for storing a motor control value for controlling a motor used for winding the seat belt;
Deterioration information acquisition means for acquiring deterioration information of a seat belt retractor including the motor;
Based on the deterioration information acquired by the deterioration information acquisition means, operation efficiency determination means for determining whether or not the operation efficiency of the seat belt retractor has decreased,
When the operation efficiency determining means determines that the operation efficiency of the seat belt retractor has decreased, the motor control value stored in the motor control value storage means is used to determine the operation of the seat belt retractor. Motor control value changing means to change so as to approach the operation when the is not reduced,
Is provided.

In the seat belt retractor,
The motor control value stored by the motor control value storage means is a voltage control value for controlling the voltage value of the motor that determines the seat belt winding speed,
The motor control value storage means is configured to increase the voltage value of the motor when the operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased. Change the voltage control value stored by
You may do it.

In the seat belt retractor,
The motor control value stored by the motor control value storage means is a hook detection current threshold that is a threshold of the motor current value for detecting the hook of the seat belt during winding of the seat belt.
The motor control value change unit is configured to detect the catch detection current threshold value stored in the motor control value storage unit when the operation efficiency determination unit determines that the operation efficiency of the seat belt retractor is lowered. To increase the
You may do it.

In the seat belt retractor,
The motor control value stored in the motor control value storage means is a current value for restraint that is a current value of the motor for determining the tension of the seat belt when restraining an occupant,
The motor control value changing means determines the current value for restraint stored in the motor control value storage means when the operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased. Enlarge,
You may do it.

In the seat belt retractor,
The deterioration information acquisition means acquires the number of operations of the seat belt retractor as deterioration information,
The operation efficiency determination unit determines that the operation efficiency of the seat belt retractor has decreased when the number of operations acquired by the deterioration information acquisition unit exceeds a predetermined number.
You may do it.

In the seat belt retractor,
The deterioration information acquisition means acquires the use time of the seat belt retractor as deterioration information,
The operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased when the usage time acquired by the deterioration information acquisition means is a predetermined time or more.
You may do it.

In the seat belt retractor,
The deterioration information acquisition means acquires the value of the inrush current of the motor as deterioration information,
The operating efficiency determining means determines whether or not the operating efficiency of the seat belt retractor has been lowered based on the value of the inrush current acquired by the deterioration information acquiring means.
You may do it.

In the seat belt retractor,
The deterioration information acquisition means acquires the current value of the motor during winding of the seat belt as deterioration information,
The operating efficiency determining means determines whether or not the operating efficiency of the seat belt retractor has been lowered based on the current value acquired by the deterioration information acquiring means.
You may do it.

In the seat belt retractor,
Supply voltage value acquisition means for acquiring a supply voltage value supplied to the seat belt retractor;
Supply voltage value determining means for determining whether or not the supply voltage value acquired by the supply voltage value acquiring means is smaller than a predetermined voltage value;
When the supply voltage value determining means determines that the supply voltage value is smaller than a predetermined voltage value, the voltage control value stored by the motor control value storage means is changed so as to increase the voltage value of the motor. Voltage control value changing means,
You may do it.

In the seat belt retractor,
An ambient temperature acquisition means for acquiring an ambient temperature of the seat belt retractor;
Temperature determining means for determining whether or not the ambient temperature acquired by the ambient temperature acquiring means is higher than a predetermined temperature;
Voltage control value change for changing the voltage control value stored in the motor control value storage means so as to decrease the voltage value of the motor when the temperature determination means determines that the ambient temperature is higher than a predetermined temperature. Means further comprising:
You may do it.

The seat belt retractor according to the second aspect of the present invention is
A motor,
A winding mechanism that winds up the seat belt using the rotation of the motor;
Motor control value storage means for storing a motor control value for controlling the motor;
Deterioration information acquisition means for acquiring deterioration information of the winding mechanism;
Based on the deterioration information acquired by the deterioration information acquisition means, operation efficiency determination means for determining whether or not the efficiency of the seat belt winding operation has decreased,
When the operation efficiency determining means determines that the efficiency of the seat belt retracting operation has decreased, the motor control value stored in the motor control value storage means is stored, and the efficiency of the seat belt retracting operation is decreased. Motor control value changing means to change so as to approach the operation when not,
Is provided.

Further, the seat belt winding control method according to the third aspect of the present invention includes:
A deterioration information acquisition step of acquiring deterioration information of a seat belt retractor including a motor used for winding the seat belt;
A condition reading step of reading out the condition from a storage unit that stores the condition of deterioration information indicating that the operating efficiency of the seat belt retractor has decreased;
A condition determining step for determining whether the deterioration information acquired in the deterioration information acquiring step satisfies the condition read in the condition reading step;
When it is determined that the deterioration information satisfies the condition in the condition determining step, the initial value of the motor control value for controlling the motor is used, and the operation efficiency of the seat belt retractor is not lowered. A motor control value change step for changing to a change value to approximate the operation of
Is provided.

A program according to the fourth aspect of the present invention is:
On the computer,
A deterioration information acquisition step of acquiring deterioration information of a seat belt retractor including a motor used for winding the seat belt;
Based on the deterioration information acquired in the deterioration information acquisition step, an operation efficiency determination step of determining whether or not the operation efficiency of the seat belt retractor has decreased,
When it is determined in the operation efficiency determination step that the operation efficiency of the seat belt retractor has decreased, a motor control value for controlling the motor stored in the storage unit is stored in the seat belt retractor. A motor control value change step to change so that the operation of the
Is executed.

  According to the present invention, the seat belt retracting operation can be appropriately executed even when the efficiency of the seat belt retracting operation by the motor is lowered.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following, an embodiment will be described by taking a retractor (seat belt retractor) equipped with a controller (seat belt retractor) for controlling the motor as an example.

[First Embodiment]
FIG. 1 is a diagram schematically illustrating a configuration example of a seat belt device including a retractor according to the first embodiment of the present invention.
The seat belt device is provided in a vehicle seat (seat), and includes a retractor 1, a belt 2, a belt anchor 3, a guide anchor 4, a tongue plate 5, and a buckle 6, as shown in the figure. Prepare.

The retractor 1 is a device that winds up the belt 2, and is fixed to the inside of the side surface of the vehicle body. In addition, the retractor 1 which concerns on this Embodiment is a motor retractor which is provided with a motor and can wind up the belt 2 with the motive power of a motor.
The belt 2 is a webbing for restraining an occupant to a seat, and one end is attached to the retractor 1.

The belt anchor 3 is for fixing one end of the belt 2 to the floor (or seat) of the vehicle body, and is attached to the end of the belt 2 opposite to the end to which the retractor 1 is attached. .
The guide anchor 4 is for folding the belt 2 in the vicinity of the passenger's shoulder, and the belt 2 is inserted and fixed to the side surface of the vehicle.

The tongue plate 5 is engaged with the buckle 6 when the occupant wears the seat belt, and is slidably supported by the belt 2 folded back by the guide anchor 4.
The buckle 6 is fixed to the seat (or the floor of the vehicle body), and the tongue plate 5 is detachably inserted and engaged in the vicinity of the occupant's waist. Further, the buckle 6 includes a seat belt mounting sensor 7 that detects whether the seat belt is mounted or released by detecting the engagement of the tongue plate 5. The seat belt wearing sensor 7 outputs the detected signal to the retractor 1 through a cord.

When sitting, the occupant pulls out the belt 2 from the retractor 1 and inserts the tongue plate 5 into the buckle 6 to fix it. Accordingly, the seat belt is attached to the occupant, and the occupant is restrained by the seat by the seat belt.
The occupant removes the tongue plate 5 from the buckle 6 when leaving the seat. At this time, the retractor 1 detects that the seat belt has been released based on a signal from the seat belt attachment sensor 7, and drives the motor to wind up the belt 2 drawn from the retractor 1.

FIG. 2 is a diagram schematically illustrating a configuration example of the retractor 1 according to the present embodiment.
As illustrated, the retractor 1 includes a frame 11, a spool 12, a spring portion 13, a motor 14, a power transmission mechanism portion 15, and a controller 16.

The frame 11 is a framework of the retractor 1 and has a substantially U shape.
The spool 12 is for winding the belt 2, and the belt 2 is wound around and supported on the frame 11 in a freely rotatable manner. The belt 2 is wound around the retractor 1 as the spool 12 rotates.
The spring portion 13 always biases the spool 12 in the winding direction by a spring force, is supported by the frame 11, and is connected to the spool 12 via the power transmission mechanism portion 15.

The motor 14 is an electric motor for rotating the spool 12 and is supported by the frame 11.
The power transmission mechanism 15 is for shifting the power of the motor 14 and transmitting it to the spool 12, and is supported by the frame 11. Specifically, the power transmission mechanism unit 15 includes a spool-side pulley fixed to the rotation shaft of the spool 12, a motor-side pulley fixed to the rotation shaft of the motor 14, a timing belt for connecting both pulleys, and the like. The rotation of the motor 14 is transmitted to the spool 12.

  The controller 16 is for controlling the drive of the motor 14 and is supported by the frame 11. The controller 16 is connected to the motor 14, a power supply that supplies driving power for the motor 14, the seat belt wearing sensor 7, a collision sensor, and the like via a cord.

FIG. 3 is a block diagram illustrating a configuration example of the controller 16 and a connection state thereof.
As shown in the figure, the controller 16 includes a motor driver 161, a current sensor 162, an ECU (Electronic Control Unit) 163, and a data storage unit 164.

  The motor driver 161 is connected to the power supply 8, and a power supply voltage is applied from the power supply 8. The power source 8 is an in-vehicle battery or the like. The motor driver 161 applies a voltage to the motor 14 and drives the motor 14 according to control by the ECU 163.

  The current sensor 162 is installed between the motor driver 161 and the motor 14 and detects the value of the current flowing through the motor 14. Current sensor 162 outputs the detected current value to ECU 163.

  The ECU 163 controls the motor driver 161 according to the control parameters for controlling the motor 14 and controls the motor 14 via the motor driver 161. Specifically, the ECU 163 controls the rotation of the motor 14 by a PWM (Pulse Width Modulation) method. Therefore, the ECU 163 generates a PWM signal having a predetermined duty ratio according to the control parameter, and outputs the generated PWM signal and a control signal for instructing the rotation direction of the motor 14 to the motor driver 161. The motor driver 161 applies a drive voltage obtained by adjusting a power supply voltage with a PWM signal to the motor 14. As a result, the motor 14 rotates at a speed based on the duty ratio, and the belt 2 is wound around the spool 12.

  Further, the ECU 163 determines whether or not the operating efficiency of the retractor 1 has decreased due to aging degradation or the like. If it is determined that the operating efficiency has decreased, the ECU 163 adjusts (corrects) the control parameter.

  The ECU 163 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Specifically, the control process of the motor driver 161 and the adjustment process of the control parameters by the ECU 163 are performed by the CPU using the RAM as a work area to temporarily store various data, and the control program stored in the ROM. This is done by executing Note that these processes performed by the ECU 163 will be described later.

The data storage unit 164 stores various types of information, and includes a data rewritable memory such as an EEPROM (Electrically Erasable PROM) or a flash memory.
Specifically, the data storage unit 164 stores a control parameter setting value table 201 and a setting value change condition table 202.

FIG. 4 is a diagram illustrating an example of the data structure of the control parameter setting value table 201.
The control parameter set value table 201 stores the set values of control parameters used for controlling the motor driver 161. As shown in the figure, the change parameter, the set value for each control parameter, the valid flag, Are stored in association with each other.

  The change stage is information indicating a stage of changing the set value of the control parameter. The ECU 163 determines in stages the decrease in efficiency of the seat belt retracting operation, and changes the set value of the control parameter in accordance with that stage. For example, the ECU 163 initially controls the motor 14 using the set value of the control parameter in the initial column. When the operating efficiency decreases to some extent, the motor 14 is controlled using the set value of the control parameter in the first change column. When the operation efficiency further decreases, the ECU 163 uses the control parameter setting value in the second change column, and when the operation efficiency further decreases, the ECU 163 uses the control parameter setting value in the third change column.

  The valid flag is 1-bit information indicating which change stage control parameter setting value is currently valid. For example, a flag is set in the effective flag field of the control parameter to be used at present, and a value “1” is set. On the other hand, the value “0” is set in the field of the valid flag of the control parameter that should not be used at present. The ECU 163 reads the control parameter setting value with the valid flag value “1” from the control parameter setting value table 201 and controls the motor 14.

The control parameter winding duty ratio is a control parameter for controlling the speed at which the retractor 1 winds the belt 2 (belt winding speed).
The voltage applied to the motor 14 is determined by a PWM signal generated based on the set value of the winding duty ratio. The belt winding speed (belt retracting speed) increases as the voltage applied to the motor 14 increases. For this reason, the belt winding speed is controlled by the winding duty ratio.

The hook detection current threshold is a control parameter for stopping the winding operation by the retractor 1 when the belt 2 is caught by an occupant or the like while the belt 2 is being wound by the retractor 1.
When the belt 2 is caught by an occupant or the like while the belt 2 is being wound by driving the motor 14, the load applied to the motor 14 increases and the motor current increases. Therefore, a value larger than the value of the motor current when the belt 2 is wound up without being caught by an occupant or the like is set as the setting value of the current threshold value for hook detection. When the value of the motor current during belt winding becomes equal to or greater than the set value of the catch detection current threshold, the retractor 1 assumes that the belt 2 has been caught by an occupant or the like and stops the winding operation.

The occupant restraint current value is a control parameter for controlling the tension of the seat belt (occupant restraint tension) for restraining the occupant in an emergency such as a vehicle collision.
In an emergency, the retractor 1 pulls the belt 2 strongly and restrains the occupant to the seat with a constant tension of the seat belt. The tension of the seat belt based on the torque of the motor 14 increases as the motor current increases. For this reason, the tension of the seat belt is controlled by the occupant restraint current value.

FIG. 5 is a diagram illustrating an example of the data structure of the set value change condition table 202.
As shown in the figure, the set value change condition table 202 is associated with the change stage of the set value of the control parameter, a set value change condition for changing the set value, and a changed flag indicating whether or not it has been changed. And memorize.

  Specifically, the ECU 163 determines a decrease in the efficiency of the seat belt retracting operation based on the number of retracting operations of the retractor 1. As the number of winding operations increases, the deterioration of the mechanisms such as the motor 14, the power transmission mechanism, and the spool 12 progresses, and as a result, the operation efficiency decreases. The ECU 163 refers to the set value change condition table 202, and when the number of winding operations exceeds the number of operations indicated in the set value change condition, the ECU 163 considers that the operation efficiency has decreased, and sets the control parameter. Adjust the value.

  For example, the ECU 163 changes (adjusts) the first set value when the number of winding operations of the retractor 1 reaches 30,000, and when it reaches 60,000, the second setting When the value is changed and reaches 90,000 times, the third set value is changed.

  The changed flag is 1-bit information indicating whether or not the set value of the control parameter has been changed for each change stage. For example, the changed flag is set to “0” as an initial value. When the number of winding operations of the retractor 1 satisfies the set value change condition, the changed flag at the change stage where the set value change condition is satisfied is set and set to the value “1”.

  Returning to FIG. 3, signals are input to the ECU 163 from the seat belt mounting sensor 7, the collision sensor 9, and the current sensor 162. Here, the collision sensor 9 is a sensor that detects a collision (or predicted collision) of the vehicle, and is provided in front of the vehicle. The collision sensor 9 is connected to the controller 16 via a cord, and outputs a collision detection signal to the ECU 163 when a collision is detected.

  The ECU 163 generates a motor based on input signals from the sensors of the seat belt mounting sensor 7, the collision sensor 9, and the current sensor 162 and the setting values of the control parameter setting value table 201 stored in the data storage unit 164. Control processing of the driver 161 is performed.

  For example, when the ECU 163 detects the release of the seat belt based on a signal from the seat belt attachment sensor 7, the ECU 163 obtains the setting value of the winding duty ratio at the change stage where the valid flag is “1” from the control parameter setting value table 201. Read and generate a PWM signal of the read duty ratio. The ECU 163 outputs the generated PWM signal and a control signal for rotating the motor 14 in the winding direction to the motor driver 161. As a result, the motor 14 rotates and the belt 2 is wound at a winding speed corresponding to the set value of the winding duty ratio.

  Further, when the winding of the belt 2 starts, the ECU 163 reads the set value of the hook detection current threshold value at the change stage where the valid flag is “1” from the control parameter set value table 201. Then, the ECU 163 compares the value of the motor current detected by the current sensor 162 with the catch detection current threshold while the belt 2 is being wound, and the motor current value becomes equal to or greater than the catch detection current threshold. Then, the motor driver 161 is instructed to stop driving, and the rotation of the motor 14 is stopped. As a result, when the belt 2 is caught by an occupant or the like during the winding operation by the retractor 1, the winding operation is stopped.

  Further, when the ECU 163 receives a collision detection signal from the collision sensor 9, the ECU 163 reads from the control parameter setting value table 201 the setting value of the occupant restraining current value at the change stage where the valid flag is “1”. The ECU 163 performs feedback control so that the value of the motor current detected by the current sensor 162 becomes the occupant restraining current value. Specifically, when the motor current value is smaller than the occupant restraining current value, the ECU 163 increases the duty ratio to increase the voltage applied to the motor 14, and the motor current value is greater than the occupant restraining current value. In this case, the duty ratio is reduced to reduce the voltage applied to the motor 14. Thereby, at the time of a collision, a passenger | crew is restrained by a seat with a fixed tension according to the setting value of the electric current value for passenger | crew restraint.

  The ECU 163 reads out the setting values of each control parameter from the control parameter setting value table 201, for example, when the vehicle ignition key is turned on, and stores it in a RAM setting value register or the like. You may make it leave.

Next, control parameter adjustment processing executed by the ECU 163 will be described.
The retractor 1 winds up the belt 2 by transmitting the power of the motor 14 to the spool 12 via the power transmission mechanism 15. Therefore, by repeating the winding operation of the belt 2, the mechanical portions such as the motor 14, the power transmission mechanism portion 15, and the spool 12 are gradually deteriorated, and the power transmission loss increases. That is, when the retractor 1 deteriorates over time, the internal power transmission loss increases, and the efficiency of the belt winding operation decreases.

Specifically, when the loss of power transmitted from the motor 14 to the spool 12 increases, the load applied to the motor 14 increases.
Therefore, after the operating efficiency is lowered, even when the same drive voltage as that before the operating efficiency is reduced is applied to the motor 14, the belt winding speed becomes smaller than that before the operating efficiency is reduced.

  In addition, when the load applied to the motor 14 increases, the motor current increases. Therefore, even if the load is not detected as a catch before the operation efficiency is lowered, It can happen that a catch is detected.

  Therefore, the ECU 163 determines a decrease in operating efficiency based on the deterioration information indicating the deterioration state of the retractor 1 and, when determining that the operating efficiency has decreased, the control parameter set value table 201 so as to cancel the influence of the decrease in operating efficiency. Adjust (change) the set value of the control parameter stored in.

  For example, the belt winding speed becomes smaller due to a decrease in operating efficiency. Therefore, as shown in the example of the control parameter setting value table 201 in FIG. 4, the winding duty ratio is changed to a stage where the operating efficiency is reduced to compensate for the reduction in operating efficiency and approach the initial belt winding speed. In response, increase gradually. Thus, even when the operation efficiency is lowered due to deterioration over time, the belt winding speed can be kept substantially constant and the change can be minimized.

In addition, the motor current during winding increases due to an increase in load due to a decrease in operating efficiency. Therefore, if the current threshold value for detecting the catch is constant, even if a load that is not detected as a catch before the operating efficiency is lowered, it may be determined as a catch after the operating efficiency is lowered.
Therefore, as shown in the example of the control parameter setting value table 201 in FIG. 4, the catch detection current threshold value is gradually set according to the change stage of the reduction in operation efficiency so that the catch detection judgment standard is brought closer to the initial standard. Make it bigger. Thereby, even when the operation efficiency is lowered due to deterioration over time, the reference of the load applied to the motor 14 due to the catch can be kept substantially constant, and the change can be minimized.

When the operating efficiency is reduced and the load applied to the motor 14 is increased, the initial occupant restraining current value decreases the tension of the belt 2 by the increased load.
Therefore, as shown in the example of the control parameter setting value table 201 in FIG. 4, the occupant restraining current value is changed according to the change stage of the reduction in operating efficiency so that the occupant restraining tension in the emergency approaches the initial tension. Increase gradually. Note that 0 <Ia1 <Ia2 <Ia3 <Ia4.

  In this way, by changing the control parameter, the retractor 1 can perform an operation close to a constant operation with almost no decrease in operating efficiency.

FIG. 6 is a block diagram illustrating a functional configuration example of the ECU 163 having a control parameter adjustment function.
The ECU 163 includes a deterioration information acquisition unit 301, a set value change determination unit 302, and a set value change unit 303, as illustrated.

  The deterioration information acquisition unit 301 acquires deterioration information of the retractor 1. Specifically, the deterioration information acquisition unit 301 acquires the number of winding operations of the retractor 1 as deterioration information. For example, the deterioration information acquisition unit 301 counts the number of times each time the ECU 163 outputs a control signal instructing the motor driver 161 to wind, and stores the number of operations in the RAM.

Note that the number of operations may be acquired by counting the release of seat belt attachment based on a signal from the seat belt attachment sensor 7.
In addition, the deterioration information acquisition unit 301 may store the acquired deterioration information in the data storage unit 164 and read and acquire it during the control parameter adjustment processing.

The setting value change determination unit 302 determines the setting value of the control parameter stored in the control parameter 201 based on the deterioration information acquired by the deterioration information acquisition unit 301 and the setting value change condition stored in the setting value change condition table 202. Determine whether to change.
Specifically, when the deterioration information is input from the deterioration information acquisition unit 301, the setting value change determination unit 302 refers to the setting value change condition table 202, and the deterioration information indicates the setting value of the changed flag “0”. It is determined whether or not the change condition is satisfied. If it is satisfied, the set value change determination unit 302 determines that the set value is to be changed, assuming that the operating efficiency of the retractor 1 has decreased. In other words, the set value change determination unit 302 determines whether or not the operating efficiency of the retractor 1 has decreased.

  When the setting value change determination unit 302 determines that the setting value of the control parameter is to be changed, the setting value change determination unit 302 reads the change stage information satisfying the setting value change condition from the setting value change condition table 202 and outputs the information to the setting value change unit 303. . Furthermore, the set value change determination unit 302 sets the changed flag at the change stage where the set value change condition is satisfied to “1” in the set value change condition table 202.

  When the change value information is input from the set value change determination unit 302, the set value change unit 303 sets the change stage valid flag to “1” in the control parameter set value table 201, and sets the other change step information. Set the valid flag to “0”.

When the seat belt is retracted, the ECU 163 reads from the control parameter setting value table 201 the setting value of the control parameter at the change stage where the valid flag is set to “1”, and controls the motor 14 based on the setting value. .
For this reason, after the operating efficiency of the retractor 1 is lowered, the set value of the control parameter is changed so that an operation close to the operation of the retractor 1 when the operating efficiency is not lowered is executed. Therefore, the retractor 1 can perform a close operation when the operation efficiency is not lowered, even when the operation efficiency is lowered.

FIG. 7 is a flowchart showing control parameter adjustment processing according to the present embodiment.
This control parameter adjustment process is started, for example, when the winding of the belt 2 is completed. Note that this may be performed when the ignition switch is turned on.

First, the deterioration information acquisition unit 301 acquires the number of winding operations of the retractor 1 as deterioration information (step S1).
Next, the set value change determination unit 302 determines whether or not all changed flags in the set value change condition table 202 are “1” (step S2).

If all the changed flags are “1” (step S2; YES), the control parameter setting value cannot be changed any more, and the control parameter adjustment process is terminated.
When all the changed flags are not “1” (step S2; NO), the set value change determination unit 302 changes the change stage from the set value change condition table 202 in the change stage where the changed flag is “0”. Reads the setting value changing condition with the minimum (step S3).

Next, the set value change determination unit 302 determines whether or not the number of winding operations acquired in step S1 is equal to or greater than the number of operations of the set value change condition (step S4).
If the number of winding operations is not greater than or equal to the number of operations of the set value changing condition (step S4; NO), it is considered that the operation efficiency has not been reduced, and this control parameter adjustment processing is terminated.

If the number of winding operations is equal to or greater than the number of operations of the set value change condition (step S4; YES), the set value change determination unit 302 uses the set value change condition read in step S3 from the set value change condition table 202. The corresponding change stage is read (step S5).
Further, the set value change determination unit 302 sets the changed flag of the set value change condition table 202 corresponding to the read change stage to “1” (step S6).

  Subsequently, the set value changing unit 303 accesses the control parameter set value table 201, sets the valid flag corresponding to the change stage read in step S5 to “1”, and sets the other valid flags to “0”. (Step S7), the control parameter adjustment process is terminated.

  With the above control parameter adjustment processing, it is possible to determine a decrease in the operating efficiency of the retractor 1 based on the number of winding operations indicating the deterioration state of the retractor 1. Then, the set value of the control parameter can be adjusted stepwise according to the degree of decrease in operating efficiency.

[Second Embodiment]
In the said 1st Embodiment, the frequency | count of winding operation | movement of the retractor 1 was used as deterioration information for judging the operating efficiency fall of the retractor 1. FIG. However, the deterioration information is not limited to this.
Therefore, a case where the usage time of the retractor 1 is used as the deterioration information of the retractor 1 will be described as a second embodiment of the present invention.

  FIG. 8 is a block diagram illustrating a configuration example of the controller 16 and a connection state thereof in the second embodiment of the present invention. In FIG. 8, the same components as those shown in FIG. 3 in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, as shown in the figure, in addition to the components in the first embodiment, a timer unit 401 is provided.
The timekeeping unit 401 records the date and time, and is a clock circuit or the like provided in the vehicle. The time measuring unit 401 is connected to the controller 16 via a cord and outputs the current date and time information to the ECU 163. Note that the controller 16 may include a timer such as a built-in timer.

  The data storage unit 164 stores the use start date and time of the retractor 1. When acquiring deterioration information, the deterioration information acquisition unit 301 of the ECU 163 in the present embodiment reads the use start date and time from the data storage unit 164, for example, and reads the read use start date and time from the time measuring unit 401. The usage time is obtained by subtracting from the date and time information.

The set value change condition table in the present embodiment is different from the set value change condition table 202 in the first embodiment in the set value change conditions.
FIG. 9 is a diagram illustrating a data structure example of the set value change condition table 402 according to the second embodiment of the present invention.

  The set value change determining unit 302 refers to the set value change condition table 402 when determining whether to change the set value of the control parameter. For example, when the usage time of the retractor 1 is 5 years or more, Change (adjust) the first set value, change the second set value when it is over 10 years, and change the third set value when over 15 years Is determined.

  According to the second embodiment of the present invention, it is possible to determine a decrease in the operating efficiency of the retractor 1 based on the usage time indicating the deterioration state of the retractor 1. Then, the set value of the control parameter can be adjusted stepwise according to the degree of decrease in operating efficiency.

[Third Embodiment]
Moreover, the value of the inrush current of the motor 14 can also be used as deterioration information for determining a decrease in operating efficiency of the retractor 1.
Therefore, a case where the value of the inrush current of the motor 14 is used as the deterioration information of the retractor 1 will be described as a third embodiment of the present invention.

  The deterioration information acquisition unit 301 of the ECU 163 in the present embodiment extracts and acquires the value of the inrush current from the current value input from the current sensor 162 as the deterioration information. It is also possible to store the values of the most recent inrush currents, obtain the average value (including the weighted average value), and use it as deterioration information.

Also, the set value change condition table in the present embodiment is different from the set value change condition table 202 in the first and second embodiments in the set value change condition.
FIG. 10 is a diagram illustrating a data structure example of the set value change condition table 501 according to the third embodiment of the present invention.

  The set value change determining unit 302 refers to the set value change condition table 501 when determining whether or not to change the set value of the control parameter. For example, when the inrush current is equal to or greater than Ib1 [A], the set value change determining unit 302 Change (adjust) the first setting value, change the second setting value when Ib2 [A] or more, and change the third setting value when Ib3 [A] or more Is determined to be performed. Note that 0 <Ib1 <Ib2 <Ib3.

  According to the third embodiment of the present invention, it is possible to determine a decrease in the operating efficiency of the retractor 1 based on the value of the inrush current of the motor 14 indicating the deterioration state of the retractor 1. Then, the set value of the control parameter can be adjusted stepwise according to the degree of decrease in operating efficiency.

[Fourth Embodiment]
In addition, as deterioration information for determining a decrease in operating efficiency of the retractor 1, an average value of the current of the motor 14 during the belt winding operation can be used.
Therefore, a case where the average value of the current of the motor 14 during the belt winding operation is used as the deterioration information of the retractor 1 will be described as a fourth embodiment of the present invention.

  For example, the deterioration information acquisition unit 301 of the ECU 163 in the present embodiment stores the current value input from the current sensor 162 at predetermined time intervals during the belt winding operation, and when the belt winding operation is completed, the stored current is stored. An average value is obtained and acquired as deterioration information.

Further, the set value change condition table in the present embodiment is different from the set value change condition table 202 in the first to third embodiments in the set value change condition.
FIG. 11 is a diagram showing an example of the data structure of the set value change condition table 601 in the fourth embodiment of the present invention.

  When the set value change determining unit 302 determines whether or not to change the set value of the control parameter, the set value change determining unit 302 refers to the set value change condition table 601 and, for example, the average current during the winding operation is equal to or greater than Ic1 [A]. Sometimes, the setting value is changed (adjusted) for the first time, and when it is Ic2 [A] or more, the second setting value is changed. When it is Ic3 [A] or more, the third setting value is changed. It is determined that the setting value is changed. Note that 0 <Ic1 <Ic2 <Ic3.

According to the fourth embodiment of the present invention, it is possible to determine a decrease in the operating efficiency of the retractor 1 based on the average value of the current of the motor 14 during the belt winding operation indicating the deterioration state of the retractor 1. Then, the set value of the control parameter can be adjusted stepwise according to the degree of decrease in operating efficiency.
The average value may be an average value weighted immediately after the start of the winding operation, in the middle or just before the end.

[Fifth Embodiment]
In the first to fourth embodiments, the reduction in operating efficiency is determined from the deterioration information of the retractor 1 and the control parameter is adjusted. However, the operation of the retractor 1 may be determined based on information other than deterioration information, and the control parameter may be adjusted.
Therefore, as a fifth embodiment of the present invention, a case where the control parameter is adjusted based on the voltage value information of the power supply will be described.

When the power supply voltage varies, the rotational speed of the motor 14 also varies. Therefore, ECU 163 in the present embodiment adjusts the winding duty ratio in response to a change in power supply voltage.
FIG. 12 is a block diagram showing a configuration example of the controller 16 and its connection state in the fifth embodiment of the present invention. In FIG. 12, the same components as those shown in FIG. 3 in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The controller 16 in the present embodiment includes a power supply voltage sensor 701 in addition to the components of the controller 16 in the first embodiment, as shown in the figure.
The power supply voltage sensor 701 is installed on the power supply side of the motor driver 161 and detects the value of the power supply voltage supplied to the motor driver 161. The power supply voltage sensor 701 outputs the detected voltage value to the ECU 163.

Further, the data storage unit 164 in the present embodiment stores a control parameter adjustment table 702.
FIG. 13 is a diagram illustrating a data structure example of the control parameter adjustment table 702 according to the fifth embodiment of the present invention.
As shown in the figure, the control parameter adjustment table 702 stores a set value change condition and a control parameter change method in association with each other.

  The ECU 163 reads the set value change condition from the control parameter adjustment table 702 and determines whether or not the power supply voltage value input from the power supply voltage sensor 701 satisfies the set value change condition. When the power supply voltage value satisfies the set value change condition, the ECU 163 reads the control parameter change method associated with the satisfied set value change condition from the control parameter adjustment table 702, and adjusts the control parameter adjusted by the change method. The motor 14 is controlled based on the above.

  For example, when the power supply voltage value becomes equal to or lower than V1 [V], the ECU 163 controls the motor 14 using a duty ratio obtained by multiplying the winding duty ratio read from the control parameter setting value table 201 by α. In addition, when the power supply voltage value becomes equal to or higher than V2 [V], the ECU 163 controls the motor 14 using a duty ratio obtained by multiplying the winding duty ratio read from the control parameter setting value table 201 by 1 / β. . Note that 0 <V1 <V2, α> 1, and β> 1.

According to the fifth embodiment of the present invention, the set value of the control parameter can be adjusted according to the power supply voltage value.
Note that the setting value change condition may be further divided. Further, a correction coefficient or the like for changing the control parameter may be obtained from the power supply voltage value by calculation using a mathematical formula.

[Sixth Embodiment]
Further, when the atmospheric temperature of the retractor 1 changes, the motor efficiency of the motor 14 also changes in proportion to the temperature.
Therefore, as a sixth embodiment of the present invention, a case where the control parameter is adjusted based on the atmospheric temperature of the retractor 1 will be described.

When the motor efficiency varies, the rotational speed of the motor 14 also varies. Therefore, ECU 163 in the present embodiment adjusts the winding duty ratio in accordance with the change in the ambient temperature of retractor 1.
FIG. 14 is a block diagram illustrating a configuration example of the controller 16 and a connection state thereof in the sixth embodiment of the present invention. In FIG. 14, the same components as those shown in FIG. 3 in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, as shown in the figure, a temperature sensor 801 is provided in addition to the components in the first embodiment.
The temperature sensor 801 is provided in the vicinity of the retractor 1 of the vehicle, for example, and detects the ambient temperature of the retractor 1. The temperature sensor 801 outputs detected temperature information to the ECU 163.

In addition, the data storage unit 164 in the present embodiment stores a control parameter adjustment table 802.
FIG. 15 is a diagram illustrating a data structure example of the control parameter adjustment table 802 according to the sixth embodiment of the present invention.
As shown in the figure, the control parameter adjustment table 802 stores a set value change condition and a control parameter change method in association with each other.

  The ECU 163 reads the set value change condition from the control parameter adjustment table 802 and determines whether or not the temperature input from the temperature sensor 801 satisfies the set value change condition. When the temperature satisfies the set value change condition, the ECU 163 reads out the control parameter change method associated with the satisfied set value change condition from the control parameter adjustment table 802, and based on the control parameter adjusted by the change method. The motor 14 is controlled.

  For example, when the ambient temperature becomes equal to or lower than T1 [° C.], the ECU 163 controls the motor 14 using a duty ratio obtained by multiplying the winding duty ratio read from the control parameter setting value table 201 by γ. Further, when the atmospheric temperature becomes equal to or higher than T2 [° C.], the ECU 163 controls the motor 14 using a duty ratio obtained by multiplying the winding duty ratio read from the control parameter setting value table 201 by 1 / δ. Note that T1 <T2, γ> 1, and δ> 1.

According to the sixth embodiment of the present invention, the set value of the control parameter can be adjusted according to the ambient temperature.
Note that the setting value change condition may be further divided. Further, a correction coefficient or the like for changing the control parameter may be obtained from the atmospheric temperature by calculation using a mathematical formula.

Although the embodiments of the present invention have been described above, the present invention can be modified and applied in various forms and is not limited to the above embodiments.
For example, in the first to fourth embodiments, the setting value of the control parameter is changed from the initial value to three stages. However, the number of changes is not limited to this, and the number of changes is changed to, for example, four stages or more. You may make it do. Further, for example, a decrease in operating efficiency may be determined based on one set value change condition, and the set value may be changed only once.

  In the first to fourth embodiments, the control parameter change value is stored as it is in the control parameter setting value table 201. However, the correction coefficient for the initial value is stored, and the control parameter The set value may be obtained by calculation at the time of use.

  Further, the deterioration information of the first to fourth embodiments may be combined to determine a decrease in the operating efficiency of the retractor 1. For example, the control parameter may be changed when any one of the number of operations, the usage time, the inrush current, and the average current during the winding operation satisfies the set value changing condition.

In the first embodiment, an example in which a seat belt device is provided in a seat of a vehicle has been described. However, the present invention is not limited to a vehicle and is applied to an airplane or the like provided with a seat belt device in a seat. Also good.
Moreover, each process in the flowchart demonstrated by the said embodiment is not limited to the order, In the range which does not deviate from the meaning of this invention, an order can be changed arbitrarily.

The values such as the set value changing condition and the control parameter in the above embodiment are examples, and can be arbitrarily changed without departing from the gist of the present invention. For example, the value of the set value change condition may be a value that serves as a reference for determining a decrease in the efficiency of the seat belt retracting operation. Further, the set value of the control parameter may be a value that is controlled so that the retractor performs a certain operation regardless of the change stage according to the operation efficiency.
Furthermore, in the above embodiment, the voltage value and the current value are positive values. However, when the motor control or the like is performed with a negative value, the absolute value corresponds to the numerical value in the above embodiment. As described above, values such as a set value change condition and a control parameter may be set.

In addition, the function of the ECU 163 in the above embodiment can be realized not only by software but also by dedicated hardware.
The ECU 163 can also be realized by a normal computer system.

  For example, in the embodiment described above, the ECU 163 having a motor control function and a control parameter adjustment function has been described as having an operation program stored in advance in a memory or the like. However, a computer-readable recording medium such as a flexible disk, CD-ROM (Compact Disk Read-Only Memory), DVD (Digital Versatile Disk), MO (Magneto-Optical disk), etc. An apparatus that executes the above-described processing operation may be configured by storing and distributing the program in a medium and installing the program in a computer.

Further, the program may be stored in a disk device or the like included in a predetermined server device on a communication network such as the Internet, and may be downloaded onto a computer by being superimposed on a carrier wave, for example. Furthermore, the above-described processing can also be achieved by starting and executing a program while transferring it via a communication network.
In addition, when the above functions are realized by sharing an OS (Operating System), or when the functions are realized by cooperation between the OS and an application, only the part other than the OS may be stored in a medium and distributed. Alternatively, it may be downloaded to a computer.

It is a figure which shows typically the structural example of a seatbelt apparatus provided with the retractor which concerns on the 1st Embodiment of this invention. It is a figure which shows typically the structural example of the retractor which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the controller in the 1st Embodiment of this invention, and its connection state. It is a figure which shows the example of a data structure of the control parameter setting value table in the 1st Embodiment of this invention. It is a figure which shows the example of a data structure of the setting value change condition table in the 1st Embodiment of this invention. It is a block diagram which shows the functional structural example of ECU which has a control parameter adjustment function in the 1st Embodiment of this invention. It is a flowchart which shows the control parameter adjustment process in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the controller in the 2nd Embodiment of this invention, and its connection state. It is a figure which shows the example of a data structure of the setting value change condition table in the 2nd Embodiment of this invention. It is a figure which shows the example of a data structure of the setting value change condition table in the 3rd Embodiment of this invention. It is a figure which shows the example of a data structure of the setting value change condition table in the 4th Embodiment of this invention. It is a block diagram which shows the structural example of the controller in the 5th Embodiment of this invention, and its connection state. It is a figure which shows the example of a data structure of the control parameter adjustment table in the 5th Embodiment of this invention. It is a block diagram which shows the structural example of the controller in the 6th Embodiment of this invention, and its connection state. It is a figure which shows the example of a data structure of the control parameter adjustment table in the 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Retractor 2 Belt 3 Belt anchor 4 Guide anchor 5 Tongue plate 6 Buckle 7 Seat belt mounting sensor 8 Power supply 9 Collision sensor 11 Frame 12 Spool 13 Spring part 14 Motor 15 Power transmission mechanism part 16 Controller 161 Motor driver 162 Current sensor 163 ECU
164 Data storage unit 201 Control parameter set value table 202, 402, 501, 601 Set value change condition table 301 Degradation information acquisition unit 302 Set value change discriminating unit 303 Set value change unit 401 Timing unit 701 Power supply voltage sensor 702, 802 Control parameter Adjustment table 801 Temperature sensor

Claims (13)

Motor control value storage means for storing a motor control value for controlling a motor used for winding the seat belt;
Deterioration information acquisition means for acquiring deterioration information of a seat belt retractor including the motor;
Based on the deterioration information acquired by the deterioration information acquisition means, operation efficiency determination means for determining whether or not the operation efficiency of the seat belt retractor has decreased,
When the operation efficiency determining means determines that the operation efficiency of the seat belt retractor has decreased, the motor control value stored in the motor control value storage means is used to determine the operation of the seat belt retractor. Motor control value changing means to change so as to approach the operation when the is not reduced,
A seat belt retractor comprising: The motor control value stored by the motor control value storage means is a voltage control value for controlling the voltage value of the motor that determines the seat belt winding speed,
The motor control value storage means is configured to increase the voltage value of the motor when the operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased. Change the voltage control value stored by
The seat belt retractor according to claim 1. The motor control value stored by the motor control value storage means is a hook detection current threshold that is a threshold of the motor current value for detecting the hook of the seat belt during winding of the seat belt.
The motor control value change unit is configured to detect the catch detection current threshold value stored in the motor control value storage unit when the operation efficiency determination unit determines that the operation efficiency of the seat belt retractor is lowered. To increase the
The seat belt retractor according to claim 1. The motor control value stored in the motor control value storage means is a current value for restraint that is a current value of the motor for determining the tension of the seat belt when restraining an occupant,
The motor control value changing means determines the current value for restraint stored in the motor control value storage means when the operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased. Enlarge,
The seat belt retractor according to claim 1. The deterioration information acquisition means acquires the number of operations of the seat belt retractor as deterioration information,
The operation efficiency determination unit determines that the operation efficiency of the seat belt retractor has decreased when the number of operations acquired by the deterioration information acquisition unit exceeds a predetermined number.
The seat belt retractor according to any one of claims 1 to 4, wherein the seat belt retractor is provided. The deterioration information acquisition means acquires the use time of the seat belt retractor as deterioration information,
The operation efficiency determination means determines that the operation efficiency of the seat belt retractor has decreased when the usage time acquired by the deterioration information acquisition means is a predetermined time or more.
The seat belt retractor according to any one of claims 1 to 4, wherein the seat belt retractor is provided. The deterioration information acquisition means acquires the value of the inrush current of the motor as deterioration information,
The operating efficiency determining means determines whether or not the operating efficiency of the seat belt retractor has been lowered based on the value of the inrush current acquired by the deterioration information acquiring means.
The seat belt retractor according to any one of claims 1 to 4, wherein the seat belt retractor is provided. The deterioration information acquisition means acquires the current value of the motor during winding of the seat belt as deterioration information,
The operating efficiency determining means determines whether or not the operating efficiency of the seat belt retractor has been lowered based on the current value acquired by the deterioration information acquiring means.
The seat belt retractor according to any one of claims 1 to 4, wherein the seat belt retractor is provided. Supply voltage value acquisition means for acquiring a supply voltage value supplied to the seat belt retractor;
Supply voltage value determining means for determining whether or not the supply voltage value acquired by the supply voltage value acquiring means is smaller than a predetermined voltage value;
When the supply voltage value determining means determines that the supply voltage value is smaller than a predetermined voltage value, the voltage control value stored by the motor control value storage means is changed so as to increase the voltage value of the motor. Voltage control value changing means,
The seatbelt take-up control device according to claim 2. An ambient temperature acquisition means for acquiring an ambient temperature of the seat belt retractor;
Temperature determining means for determining whether or not the ambient temperature acquired by the ambient temperature acquiring means is higher than a predetermined temperature;
Voltage control value change for changing the voltage control value stored in the motor control value storage means so as to decrease the voltage value of the motor when the temperature determination means determines that the ambient temperature is higher than a predetermined temperature. Means further comprising:
The seatbelt take-up control device according to claim 2. A motor,
A winding mechanism that winds up the seat belt using the rotation of the motor;
Motor control value storage means for storing a motor control value for controlling the motor;
Deterioration information acquisition means for acquiring deterioration information of the winding mechanism;
Based on the deterioration information acquired by the deterioration information acquisition means, operation efficiency determination means for determining whether or not the efficiency of the seat belt winding operation has decreased,
When the operation efficiency determining means determines that the efficiency of the seat belt retracting operation has decreased, the motor control value stored in the motor control value storage means is stored, and the efficiency of the seat belt retracting operation is decreased. Motor control value changing means to change so as to approach the operation when not,
A seat belt retractor comprising: A deterioration information acquisition step of acquiring deterioration information of a seat belt retractor including a motor used for winding the seat belt;
A condition reading step of reading out the condition from a storage unit that stores the condition of deterioration information indicating that the operating efficiency of the seat belt retractor has decreased;
A condition determining step for determining whether the deterioration information acquired in the deterioration information acquiring step satisfies the condition read in the condition reading step;
When it is determined that the deterioration information satisfies the condition in the condition determining step, the initial value of the motor control value for controlling the motor is used, and the operation efficiency of the seat belt retractor is not lowered. A motor control value change step for changing to a change value to approximate the operation of
A seat belt winding control method comprising: On the computer,
A deterioration information acquisition step of acquiring deterioration information of a seat belt retractor including a motor used for winding the seat belt;
Based on the deterioration information acquired in the deterioration information acquisition step, an operation efficiency determination step of determining whether or not the operation efficiency of the seat belt retractor has decreased,
When it is determined in the operation efficiency determination step that the operation efficiency of the seat belt retractor has decreased, a motor control value for controlling the motor stored in the storage unit is stored in the seat belt retractor. A motor control value change step to change so that the operation of the
A program for running

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