JP4622622B2 - Vehicle steering control device - Google Patents

Description

  The present invention belongs to the technical field of a vehicle steering control device including a cable column unit that mechanically connects a steering unit operated by a driver and a steering unit that steers steered wheels with a cable.

  Conventionally, in a steer-by-wire system in which a steering unit operated by a driver and a steered unit that steers steered wheels are mechanically separated, the mechanical unit between the steering unit and the steered unit when the system fails In order to secure the connection, a vehicle steering apparatus in which a steering unit and a steered unit are connected by a backup cable mechanism is known (for example, see Patent Document 1).

In addition, a cable-type steering device is also known in which a tension holding means for holding the tension of the inner cable is provided in order to prevent the steering rigidity from being lowered due to the extension of the operation cable (for example, patent document). 2).
JP 2002-225733 A JP 2004-189108 A

  However, in the conventional vehicle steering apparatus, since the abnormal extension of the cable of the backup cable mechanism is not monitored even on the steer-by-wire system side, there is no means for the driver to know the abnormal extension of the cable. In addition, since the backup cable mechanism functions when the system fails, it is difficult for the driver to recognize during normal travel by steer-by-wire even if an abnormality occurs in the cable. Therefore, when a part other than the backup cable mechanism of the steer-by-wire system breaks down and is switched to steering by mechanical connection using the cable, if the cable is abnormally stretched, the steering response of the vehicle is significantly reduced. There was a problem.

  The present invention has been made paying attention to the above-mentioned problem, and since the driver can know in advance the abnormal elongation of the cable based on the accurate cable elongation determination, it can cope with in advance, so switching to steering using the cable An object of the present invention is to provide a vehicle steering control device that can prevent the steering response of the vehicle from being deteriorated.

In order to achieve the above object, in the present invention, a vehicle steering control including a cable column unit that mechanically connects a steering unit operated by a driver and a steered unit that steers steered wheels with a cable. In the device
Wherein when the steering unit is rotated to the left and right, the steering unit based on a parameter related to the force for rotating the determines whether or not the cable fully extended, the steering portion when it is determined that the cable is fully extended A cable extension determining means for determining whether or not an abnormality in cable extension has occurred based on the rotational position is provided.

Therefore, in the vehicle steering control device of the present invention, when the steering unit is rotated left and right, the cable extension determination means determines that the cable is based on the rotation position of the steering unit when the cable is determined to be fully extended. It is determined whether or not an elongation abnormality has occurred . This cable elongation determination allows the driver to know in advance the abnormal cable elongation based on the accurate cable elongation determination, so that the driver can cope in advance, so when switching to steering using the cable, the steering response of the vehicle Can be prevented in advance.

  Hereinafter, the best mode for carrying out the vehicle steering control apparatus of the present invention will be described based on Examples 1 to 4 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing the vehicle steering control device of the first embodiment, and FIG. 2 is a plan view showing a backup cable mechanism of the vehicle steering control device of the first embodiment.
As shown in FIG. 1, the vehicle steering control apparatus according to the first embodiment includes a steering handle 1 (steering unit), a torque sensor 2 (steering torque detection means), and a steering handle angle sensor 3 (steering rotation angle detection means). A reaction force motor 4 (steering reaction force actuator), a reaction force control device 5, a backup clutch 6, a backup cable mechanism 7 (cable column portion), a steering angle sensor 8 (steering angle detection means), A steering motor 9, a steering control device 10, a steering actuator 11 (steering unit), a steered wheel 12, a communication line 13, a steering torque sensor 19 (steering torque detection means), It has.

As shown in FIG. 2, the backup cable mechanism 7 according to the first embodiment includes pulleys 14 and 14, cases 15 and 15, an inner cable 16 (cable), outer cables 17 and 17 (cable), and a tension adjustment spring. 18 and 18.
The backup cable mechanism 7 including pulleys 14 and 14 for transmitting the rotation of the steering handle 1 to the steering actuator 11 side has a tension between the case 15 and the outer cables 17 and 17 in order to give the steering handle 1 a sense of rigidity. Adjusting springs 18 and 18 are interposed to set tension. The inner cable 16 and the outer cable 17 are hereinafter abbreviated as “backup cables 16, 17”.

During normal control, the backup clutch 6 is in an open state, and the steering handle 1 and the steering actuator 11 are mechanically separated.
When the driver keys off and the steer-by-wire system is terminated, the normally closed backup clutch 6 is engaged, whereby the steering handle 1 and the steering actuator 11 are mechanically connected via the backup clutch 6 and the backup cable mechanism 7. .
After the driver gets out of the vehicle and locks the door, the steer-by-wire system determines the extension amount of the backup cables 16 and 17.

Next, the operation will be described.
[Cable elongation judgment processing]
FIG. 3 is a flowchart showing the flow of cable extension determination processing executed in the steer-by-wire system (for example, reaction force control device 5) of the first embodiment. Each step will be described below (cable extension determination means).

  In step S1, it is determined whether the driver has turned off the key and the engine has been stopped. If yes, the process proceeds to step S3, and if no, the process proceeds to step S2.

  In step S2, following the key ON determination in step S1, normal control of the steer-by-wire system is continued during engine operation, and the process returns to step S1.

  In step S3, following the key OFF determination in step S2, the normal control of the steer-by-wire system is terminated, and the process proceeds to step S4.

  In step S4, following the end of normal control in step S3, it is determined whether or not the driver has got off the vehicle and locked the door. If yes, the process proceeds to step S5. If no, the determination in step S4 is performed. repeat.

In step S5, when it is confirmed in step S4 that the driver has exited the vehicle and locked the door, the extension amount determination of the backup cables 16, 17 is started. First, the steering wheel angle at the start of cable extension determination is measured, and the process proceeds to step S6.
Here, the steering wheel angle to be started may be the angle at that time, and is not necessarily a specific fixed angle.

In step S6, following the measurement of the steering wheel angle in step S5, a current is passed through the reaction force motor 4 in a direction that reduces the difference in proportion to the difference between the target steering wheel angle of the steering wheel 1 and the actual steering wheel angle. The steering wheel angle feedback control is started, and the process proceeds to step S7.
Here, the target steering wheel angle at the start of control is the steering wheel angle measured in step S5. By doing so, it is possible to prevent a target steering wheel angle having a smaller difference from the current steering wheel angle from being input at the start of control and an excessive reaction force motor drive current from being output.

  In step S7, following the start of steering wheel angle position control in step S6, the target steering wheel angle is gradually increased to the right, and the process proceeds to step S8. Here, although starting from the right side, the target steering wheel angle may be increased from the left side.

In step S8, following the increase of the target steering wheel angle to the right in step S7, it is determined whether or not the drive current of the reaction force motor 4 is smaller than the + threshold, and the drive current of the reaction force motor 4 is greater than the + threshold. If it is smaller, the process returns to step S7, the target steering wheel angle is further increased slightly to the right, and the driving current of the reaction force motor 4 is compared with the + threshold value. And it repeats until the drive current of the reaction force motor 4 becomes + threshold value or more, and when the drive current of the reaction force motor 4 becomes + threshold value or more, it will transfer to step S9.
In the first embodiment, the direction of the current of the reaction force motor 4 necessary for rotating the reaction force motor 4 to the right is set to +, but may be − depending on the system configuration. Further, the threshold value is determined in advance by, for example, measuring the driving current of the reaction motor 4 when the steering wheel is rotated and the backup cables 16 and 17 are fully extended in the same manner as this determination operation. Further, the threshold value may be determined from the tension characteristics of the backup cables 16 and 17.

In step S9, following the determination that the driving current of the reaction force motor 4 has exceeded the + threshold value in step S8, the steering wheel angle at that time is measured, the measured steering wheel angle is stored, and the process proceeds to step S10. To do.
That is, it is determined that the backup cables 16 and 17 are fully extended when the driving current of the reaction force motor 4 is equal to or greater than the + threshold value.

  In step S10, following the measurement of the steering wheel angle in step S9, the target steering wheel angle is gradually increased to the left, and the process proceeds to step S11.

  In step S11, following the increase of the target steering wheel angle to the left in step S10, it is determined whether or not the drive current of the reaction force motor 4 is greater than the −threshold value, and the drive current of the reaction force motor 4 is less than the −threshold value. If larger, the process returns to step S10, the target steering handle angle is further increased to the left side, and the drive current of the reaction force motor 4 is compared with the -threshold value. And it repeats until the drive current of the reaction force motor 4 becomes less than -threshold value, and when the drive current of the reaction force motor 4 becomes less than -threshold value, it will transfer to step S12.

In step S12, following the determination that the driving current of the reaction force motor 4 has become equal to or less than the −threshold value in step S11, the steering wheel angle at that time is measured, the measured steering wheel angle is stored, and the process proceeds to step S13. To do.
That is, it is determined that the drive current of the reaction force motor 4 is equal to or less than the −threshold value, so that the backup cables 16 and 17 are fully extended in the counterclockwise rotation as compared with the clockwise rotation.

  In step S13, following the measurement of the steering wheel angle in step S12, the steering wheel angle when the backup cables 16, 17 are fully extended by rotating to the right side measured in step S9 and the left side measuring in step S12 are rotated. Then, the difference between the steering wheel angle when the backup cables 16, 17 are fully extended is calculated, and the difference is set as the extension amount of the backup cables 16, 17, and the process proceeds to step S14.

  In step S14, following the calculation of the backup cable expansion amount in step S13, the system guarantees the expansion amount of the backup cables 16 and 17 calculated in step S13 in consideration of the increase in the normal use range including aging degradation. It is determined whether or not the allowable range is exceeded. If Yes, the process proceeds to Step S15. If No, the process proceeds to Step S16.

In step S15, following the determination of cable extension amount> allowable range in step S14, it is determined that the backup cables 16, 17 are abnormal, and the process proceeds to step S16.
If it is determined in this step that the cable is abnormal, the next time the system is started, the abnormality is warned with a warning lamp or the like.

  In step S16, following the determination that the cable extension amount in step S14 ≦ the allowable range, it is determined that the backup cables 16 and 17 are normal, and the process proceeds to step S16.

  In step S17, following the determination of cable abnormality / normal in step S15 or step S16, the target steering handle angle is set to the steering handle angle at the start of backup cable extension amount measurement measured in step S5, and the process proceeds to step S18. .

In step S18, following the setting of the target steering handle angle in step S17, it is determined whether or not the steering handle angle matches the target steering handle angle. If yes, the process proceeds to step S19. The determination of S18 is repeated.
That is, in step S17 and step S18, the steering wheel angle increased to the right side or the left side for determination of cable abnormality / normality is returned to the original position at the time when the steering wheel angle position control is started.

  In step S19, following the determination that the steering wheel angle matches the target steering wheel angle in step S18, the steering wheel angle position control started from step S6 is terminated.

[Background technology]
In a steer-by-wire system in which an automobile is steered by an electric motor, the steering wheel side and the turning actuator side are normally separated from each other.
However, in the event of a failure, the steering handle and the turning actuator are mechanically connected by a backup cable mechanism so that steering can be performed in the same manner as in a normal steering system.

  However, unlike the conventional steering shaft, the backup cable tends to extend when a large force is applied in either the left or right steering. And if the back-up cable slack is large, the steering wheel feels less rigid, a backlash occurs between the steering wheel and the steering actuator, and the dead zone where the steering actuator does not respond to steering of the steering wheel when steering is turned back. It becomes.

  Normally, as shown in FIG. 2, a tension adjusting spring 18 is provided to absorb the slack of the backup cables 16 and 17 and maintain the tension. Alternatively, as described in JP-A-2004-189108, a mechanism for adjusting the tension of the cable is provided. Both are designed to keep their tension in the normal range under normal usage conditions including aging.

In the steer-by-wire system, the backup clutch is normally disconnected and the backup cable is rotated according to the steering on the steering actuator side, but is not connected to the steering handle side. Does not apply great power. However, when the system is OFF, the backup clutch is engaged and the steering handle and the turning actuator are mechanically coupled to prevent the angular positional relationship between the steering handle and the turning actuator from deviating.
Such a backup cable has the following problems.

  If a large force unexpected from the system is applied from the steering handle or the steering actuator while the backup clutch is engaged, such as when the system is off, an abnormal force is applied to the backup cable, and the tension of the tension adjustment spring causes the backup cable to bend. There is a possibility that it will grow so much that it cannot be absorbed. In addition, the backup cable may be extended due to other accidental failures.

  When this cable is used in a normal steering system in which the steering wheel and the steered wheel side are mechanically connected, the cable is a mechanical part, and deterioration such as cable extension gradually increases. However, it is possible to recognize the decrease in drivability due to cable extension gradually, for example, from the start of steering, and if it is judged that there is a significant impact on the driver, it is possible to refrain from steering and send it out for repair It is.

However, in the steer-by-wire system, the backup cable is a component that functions when the system fails, and is not used during normal steering. Therefore, even if an abnormality occurs in the backup cable, it is difficult for the driver to recognize it, and unless there is any warning from the steer-by-wire system, it is difficult to be repaired as an abnormality.
Moreover, at present, the steer-by-wire system does not monitor the abnormal extension of the backup cable, so there is no means for the driver to know the abnormal extension of the backup cable.

However, once the parts other than the backup cable mechanism of the steer-by-wire system break down and switching to steering using the backup cable, if the backup cable is abnormally elongated, the steering response of the vehicle will change (decrease) significantly. End up.
In addition, although what was described in Unexamined-Japanese-Patent No. 2002-225733 is known as what utilized the cable for steering of a steer-by-wire, even with the technique currently disclosed by these gazettes, with respect to abnormal elongation of a backup cable There is no diagnosis.

[Cable elongation judgment]
On the other hand, in Example 1, in the steer-by-wire system in which the backup clutch 6 is connected when the system fails and the steering is performed by the backup cables 16 and 17, the backup clutch 6 is connected and the reaction force motor 4 is driven. At this time, cable extension amount determination means for determining the extension amount of the backup cables 16 and 17 based on the steering wheel angle and the state amount of the steering control is provided.

  As shown in the flowchart of FIG. 3, the cable extension amount determination means applies a current to the reaction force motor 4 in a direction that reduces the difference in proportion to the difference between the target steering handle angle of the steering handle 1 and the actual steering handle angle. The steering wheel angle position feedback control is performed, and when the steering wheel 1 is rotated by advancing the target steering wheel angle in either the left or right direction, a threshold value with a current necessary for rotating the steering wheel 1 is set. This is realized by determining the amount of extension of the backup cables 16 and 17 based on the steering wheel angle when exceeding.

That is, the steering wheel 1 is rotated to the right by driving the reaction force motor 4 by passing a current (steps S7 and S8), and the steering handle angle at which the driving current of the reaction force motor 4 is equal to or greater than the threshold value is set. The measurement is stored (step S9). Next, the reaction force motor 4 is driven in the reverse direction to rotate the steering handle 1 counterclockwise (steps S10 and S11). Then, the steering wheel angle at which the driving current of the reaction force motor 4 necessary for rotating the steering wheel 1 becomes equal to or less than the −threshold is measured and stored (step S12). The difference between the steering wheel angle at the previous right rotation and the steering handle angle at the current left rotation is defined as the extension amount of the backup cables 16 and 17 (step S13).
When the amount of elongation exceeds the normal range set in advance including the secular change, it is determined that abnormal elongation has occurred in the backup cables 16 and 17 (step S14 → step S15).

As shown in FIG. 2, the backup cable mechanism 7 is provided with tension adjustment springs 18 and 18 between the outer cables 17 and 17 and the case 15 in order to ensure the tension.
In the steer-by-wire system, the steering handle 1 can be rotated by passing a current through the reaction force motor 4. However, in the state where the backup clutch 6 is connected, the backup cables 16 and 17 are only extended. The steering handle 1 cannot be rotated.
This is because the backup cables 16 and 17 are connected to the steered wheels 12 and 12 via the steering actuator 11, and in a state where the steering motor 9 is not driven, a very large force is required to operate the steering actuator 11. It is because it is necessary.

  The current of the reaction force motor 4 required to rotate the steering handle 1 at this time is proportional to the tension of the tension adjusting spring 18, and as shown in FIG. 4A, when the backup cables 16, 17 are fully extended, the steering handle Even if a large amount of current for rotating 1 is supplied, the steering handle 1 hardly rotates.

  Therefore, the steering wheel angle position feedback control is performed so that a current is supplied to the reaction force motor 4 in a direction to reduce the difference in proportion to the difference between the target steering handle angle of the steering handle 1 and the actual steering handle angle. Is advanced in the left or right direction, the difference between the target steering wheel angle and the actual steering wheel angle becomes large when the backup cables 16 and 17 are fully extended, and the current flowing through the reaction motor 4 is very large. become. The current value immediately after the backup cables 16 and 17 are fully extended is obtained in advance, the angle of the steering handle 1 at that time is read using this as a threshold value, this is rotated both left and right, and the current passed through the reaction force motor 4 respectively. If the difference of the steering wheel angle where the angle exceeds the threshold value is measured, the extension amount of the backup cables 16, 17 can be estimated from the angle and the length of the backup cables 16, 17 of the pulley rotation.

As described above, in the first embodiment, when the backup cables 16 and 17 are fully extended, the actual steering wheel angle is hardly changed even when a large amount of current is supplied to the reaction force motor 4. , 17 can be accurately estimated.
The current sensor (current detection means) and the steering wheel angle sensor 3 by the motor current monitoring circuit in the reaction force control device 5 are necessary for basic control of the steer-by-wire system and are always provided. There are no parts added to estimate the amount of elongation of 16 and 17, which is useful in terms of cost.

If the angle of the steering handle 1 at that time is obtained from the amount of extension of the normal backup cables 16 and 17 (cable extension A in FIG. 4A), the angle of the steering handle 1 obtained by the above-mentioned left-right rotation is obtained. By comparing with the difference (cable extension amount B in FIG. 4A), it can be determined whether or not the extension amounts of the backup cables 16 and 17 are within an allowable range (OK range in FIG. 4B).
The normal extension of the backup cables 16 and 17 is a small angle of about ± 2 ° including the backlash of the backup clutch 6. If only normal / abnormal judgment is made, the steering handle 1 has moved beyond this angle. Can be determined at the time. Therefore, the abnormality determination time can be as short as less than 1 second even if the target steering wheel angle is advanced at a very slow speed of 360 ° / min.

Next, the effect will be described.
In the vehicle steering control device of the first embodiment, the following effects can be obtained.

(1) A backup cable that mechanically connects the steering handle 1 (steering unit) operated by the driver and the steering actuator 11 (steering unit) that steers the steered wheels 12 with backup cables 16 and 17. In the vehicle steering control device including the mechanism 7 (cable column portion), when the steering handle 1 is rotated left and right, the current value of the reaction force motor 4 that is a parameter relating to the force for rotating the steering handle 1 is determined. Whether or not the backup cables 16 and 17 are fully extended, and whether or not an abnormality in cable extension has occurred based on the rotational position of the steering handle 1 when it is determined that the backup cables 16 and 17 are fully extended . Because the cable extension judgment means (Fig. 3) is provided to judge whether or not the Since it can be dealt with in advance by knowing the correct elongation, it is possible to prevent the steering response of the vehicle from being lowered when switching to steering using a cable.

(2) A steering handle angle sensor 3 (steering rotation angle detecting means) for detecting a steering handle angle of the steering handle 1 is provided, and the cable extension determining means is configured such that the cable is connected when the steering handle 1 is rotated counterclockwise. and fully extended and the steering wheel angle when it is determined, the case and the steering wheel angle when the steering wheel 1 determines that the cable is fully extended when it is rotated clockwise, the deviation is a predetermined value or more Since it is determined that an abnormality in cable extension has occurred (step S14 → step S15), the left and right fluctuations of the steering wheel angle required for the cable to be fully extended regardless of the position of the steering wheel angle when starting the cable extension determination. Based on the width, it can be accurately determined that an abnormality in cable extension has occurred.

  (3) A reaction force motor 4 (steering reaction force actuator) that applies a steering reaction force to the steering unit is provided, and the cable extension determination means rotates the steering unit with the reaction force motor 4, so that the cable extension is increased. The cable elongation can be determined while using the existing reaction force motor 4 without cost, without adding an actuator for rotating the steering handle 1 left and right at the time of determination.

  (4) A current sensor (current detection means) for detecting the current of the reaction motor 4 is provided, and the cable extension determination means determines that the cable has been fully extended when the current value exceeds a predetermined value ( Since steps S8 and S11) are performed, the load on the reaction force motor 4 increases due to the extension of the cable, and at the same time the motor current rapidly increases, so that the extension of the cable can be accurately determined.

In the second embodiment, when the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ when the steering unit is rotated by the reaction force motor 4 exceeds a predetermined value, the backup cables 16 and 17 are fully extended. This is an example of determining that In addition, since it is the same as that of FIG.1 and FIG.2 of Example 1 in a structure, illustration and description are abbreviate | omitted.

Next, the operation will be described.
[Cable elongation judgment processing]
FIG. 5 is a flowchart showing the flow of cable extension determination processing executed in the steer-by-wire system (for example, reaction force control device 5) of the second embodiment. Each step will be described below (cable extension determination means). Steps 21 to S26 correspond to Steps S1 to S6 in FIG. 3, respectively, and Steps 33 to S39 correspond to Steps S13 to S19 in FIG.

In step S27, following the start of steering wheel angle position control in step S26, the target steering wheel angle θ ^* is gradually increased to the right, and the process proceeds to step S28. Here, although starting from the right side, the target steering wheel angle θ ^* may be increased from the left side.

In step S28, following the increase to the right of the target steering handle angle θ ^* in step S27, it is determined whether or not the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ is smaller than the threshold value. ^{If *} −θ is smaller than the + threshold value, the process returns to step S27, the target steering wheel angle θ ^* is further increased to the right side, and θ ^* −θ is compared with the + threshold value. And it repeats until (theta) ^* -(theta ⁾ becomes more than + threshold value, and when (theta) ^* -(theta ⁾ becomes more than + threshold value, it will transfer to step S29.
In the second embodiment, the direction of the current of the reaction force motor 4 necessary for rotating the reaction force motor 4 to the right is set to +, but may be − depending on the system configuration. For example, the threshold is measured in advance by rotating the steering handle in the same manner as in this determination work, and measuring the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ when the backup cables 16 and 17 are fully extended. Decide it. Further, the threshold value may be determined from the tension characteristics of the backup cables 16 and 17.

In step S29, following the determination that the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ in step S28 is greater than or equal to the + threshold value, the steering handle angle at that time is measured, and the measured steering handle angle is determined. Store it and go to step S30.
That is, it is determined that the backup cables 16 and 17 are fully extended when θ ^* −θ is equal to or greater than the + threshold value.

In step S30, following the measurement of the steering wheel angle in step S29, the target steering wheel angle θ ^* is gradually increased to the left, and the process proceeds to step S31.

In step S31, following the increase to the left of the target steering handle angle θ ^* in step S30, it is determined whether or not the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ is greater than a −threshold value, and θ ^{* If} -θ is larger than the -threshold, the process returns to step S10, the target steering wheel angle is further increased to the left, and θ ^* -θ is compared with the -threshold. And it repeats until (theta) ^* -(theta ⁾ becomes below -threshold, and when (theta) ^* -(theta ⁾ becomes below -threshold, it transfers to step S32.

In step S32, following the determination that the deviation between the target steering handle angle θ ^* and the actual steering handle angle θ in step S31 is equal to or less than the −threshold value, the steering handle angle at that time is measured, and the measured steering handle angle is determined. Store it and go to step S33.

[Cable elongation judgment]
As shown in the flowchart of FIG. 5, the cable extension amount determination unit of the second embodiment is the reaction force motor 4 in a direction that reduces the difference in proportion to the difference between the target steering handle angle of the steering handle 1 and the actual steering handle angle. performs steering wheel angular position feedback control to flow a current to, the target steering wheel angle by the advance to the left or right direction, when rotating the steering wheel 1, the steering wheel 1 target steering wheel angle theta ^* and the actual This is realized by determining the extension amounts of the backup cables 16 and 17 based on the steering handle angle when the deviation from the steering handle angle θ exceeds a certain threshold.

In other words, the steering wheel 1 is rotated to the right by driving the reaction motor 4 with a current (steps S27 and S28), and the deviation between the target steering wheel angle θ ^* and the actual steering wheel angle θ is greater than or equal to the + threshold value. The steering steering wheel angle is measured and stored (step S29). Next, the reaction force motor 4 is driven in the reverse direction to rotate the steering handle 1 counterclockwise (steps S30 and S31). Then, the steering wheel angle at which the deviation between the target steering wheel angle θ ^* and the actual steering wheel angle θ is equal to or less than the −threshold value is measured and stored (step S32). The difference between the steering wheel angle at the previous right rotation and the steering handle angle at the current left rotation is defined as the extension amount of the backup cables 16 and 17 (step S33).
When the amount of elongation exceeds the normal range set in advance including aging, it is determined that abnormal elongation has occurred in the backup cables 16 and 17 (step S34 → step S35).

  As described in the first embodiment, in the steer-by-wire system, the steering handle 1 can be rotated by passing an electric current through the reaction force motor 4, but in the state where the backup clutch 6 is connected, the backup cable 16 , 17 can be rotated only until the steering wheel 1 is extended. That is, as shown in FIG. 6A, when the backup cables 16 and 17 are fully extended, the steering handle 1 hardly rotates even when a large amount of current for rotating the steering handle 1 is supplied.

Therefore, the steering wheel angle position feedback control is performed so that a current is supplied to the reaction force motor 4 in a direction to reduce the difference in proportion to the difference between the target steering handle angle of the steering handle 1 and the actual steering handle angle. Is advanced in either the left or right direction, the difference between the target steering wheel angle and the actual steering wheel angle increases when the backup cables 16, 17 are fully extended. The difference between the target steering handle angle θ ^* and the actual steering handle angle θ due to the influence of the tension adjustment spring 18 immediately after the backup cables 16 and 17 are extended is obtained in advance, and this is used as a threshold value to determine the steering handle 1 at that time. angle reads, which was both left and right rotation, by respectively measuring the difference between the target steering wheel angle theta ^* between the steering wheel angle and the deviation between the actual steering wheel angle theta is greater than the threshold time, the angle and the pulley rotation The amount of extension of the backup cables 16 and 17 can be estimated from the length of the backup cables 16 and 17.

As described above, in the second embodiment, when the backup cables 16 and 17 are fully extended, the actual steering handle angle hardly changes even when a large amount of current is supplied to the reaction force motor 4, and the target steering handle angle θ ^* and the actual steering handle angle are not changed. Since the method using the characteristic that the deviation from θ is large is employed, the amount of extension of the backup cables 16 and 17 can be accurately estimated.
The steering wheel angle sensor 3 is a sensor that is necessary for basic control of the steer-by-wire system and is always provided. Therefore, there is no additional part for estimating the extension amount of the backup cables 16 and 17, and the cost is reduced. Also useful.

If the angle of the steering handle 1 at that time is obtained from the amount of extension of the normal backup cables 16 and 17 (cable extension A in FIG. 6 (a)), the angle of the steering handle 1 obtained by the above-mentioned left-right rotation is obtained. By comparing with the difference (cable extension amount B in FIG. 6A), it can be determined whether or not the extension amounts of the backup cables 16 and 17 are within an allowable range (OK range in FIG. 6B).
The normal extension of the backup cables 16 and 17 is a small angle of about ± 2 ° including the backlash of the backup clutch 6. If only normal / abnormal judgment is made, the steering handle 1 has moved beyond this angle. Can be determined at the time. Therefore, the abnormality determination time can be as short as less than 1 second even if the target steering wheel angle is advanced at a very slow speed of 360 ° / min.

Next, the effect will be described.
In the vehicle steering control device of the second embodiment, in addition to the effects (1), (2), and (3) of the first embodiment, the following effects can be obtained.

(5) A steering handle angle sensor 3 (steering rotation angle detecting means) for detecting the steering handle angle of the steering handle 1 is provided, and the cable elongation determining means is a target when the reaction portion motor 4 rotates the steering section. When the deviation between the steering wheel angle θ ^* and the actual steering wheel angle θ is equal to or greater than a predetermined value, it is determined that the cable is fully extended (step S28, step S31). change only the target steering wheel angle theta ^* increases hardly, utilizing the characteristic that the deviation between the target steering wheel angle theta ^* and the actual steering wheel angle theta is rapidly increased, it is possible to determine the elongation cut accurately cable.

  The third embodiment is an example in which it is determined that the backup cables 16 and 17 are fully extended when the turning torque when the steering unit is rotated by the reaction force motor 4 becomes a predetermined value or more. In addition, since it is the same as that of FIG.1 and FIG.2 of Example 1 in structure, illustration and description are abbreviate | omitted.

Next, the operation will be described.
[Cable elongation judgment processing]
FIG. 7 is a flowchart showing the flow of cable elongation determination processing executed in the steer-by-wire system (for example, reaction force control device 5) of the third embodiment. Each step will be described below (cable elongation determination means). Steps 41 to S46 correspond to Steps S1 to S6 in FIG. 3, respectively, and Steps 43 to S49 correspond to Steps S13 to S19 in FIG.

  In step S47, following the start of steering wheel angle position control in step S46, the target steering wheel angle is gradually increased to the right, and the process proceeds to step S48. Here, although starting from the right side, the target steering wheel angle may be increased from the left side.

In step S48, following the increase to the right of the target steering wheel angle in step S47, it is determined whether or not the turning torque is smaller than the + threshold. If the turning torque is smaller than the + threshold, the process returns to step S47. Increase the target steering wheel angle a little further to the right, and compare the turning torque with the + threshold. And it repeats until turning torque becomes more than + threshold, and when turning torque becomes more than + threshold, it will transfer to Step S49.
In the third embodiment, although the direction of the current of the reaction force motor 4 necessary for rotating the reaction force motor 4 to the right is set to +, it may be − depending on the system configuration. The threshold value is determined in advance by, for example, rotating the steering wheel in the same manner as this determination operation and measuring the steering torque when the backup cables 16 and 17 are fully extended. Further, the threshold value may be determined from the tension characteristics of the backup cables 16 and 17.

In step S49, following the determination that the turning torque in step S48 is equal to or greater than the + threshold value, the steering handle angle at that time is measured, the measured steering handle angle is stored, and the process proceeds to step S50.
That is, it is determined that the backup cables 16 and 17 are fully extended when the steering torque is equal to or greater than the + threshold value.

  In step S50, following the measurement of the steering wheel angle in step S49, the target steering wheel angle is gradually increased to the left, and the process proceeds to step S51.

  In step S51, following the increase of the target steering wheel angle to the left in step S50, it is determined whether or not the turning torque is greater than the -threshold value. If the turning torque is greater than the -threshold value, the process returns to step S50. The target steering wheel angle is further increased slightly to the left, and the turning torque is compared with the -threshold value. And it repeats until steering torque becomes-threshold value or less, and when steering torque becomes-threshold value or less, it transfers to step S52.

  In step S52, following the determination that the turning torque in step S51 is equal to or less than the −threshold value, the steering handle angle at that time is measured, the measured steering handle angle is stored, and the process proceeds to step S53.

[Cable elongation judgment]
As shown in the flowchart of FIG. 7, the cable extension amount determination means of the third embodiment is a reaction force motor 4 in a direction that reduces the difference in proportion to the difference between the target steering handle angle of the steering handle 1 and the actual steering handle angle. The steering wheel angle position feedback control is performed so that a current flows through the steering wheel 1 and the target steering wheel angle is advanced in either the left or right direction. This is realized by determining the amount of extension of the backup cables 16 and 17 based on the steering wheel angle when exceeding.

That is, the steering wheel 1 is rotated to the right by driving the reaction force motor 4 by passing an electric current (Steps S47 and S48), and the steering wheel angle at which the turning torque is equal to or greater than the + threshold is measured and stored ( Step S49). Next, the reaction force motor 4 is driven in the reverse direction to rotate the steering handle 1 counterclockwise (steps S50 and S51). Then, the steering wheel angle at which the turning torque is equal to or less than the threshold value is measured and stored again (step S52). The difference between the steering wheel angle at the previous right rotation and the steering handle angle at the current left rotation is set as the extension amount of the backup cables 16 and 17 (step S53).
When the amount of elongation exceeds the normal range set in advance including the secular change, it is determined that abnormal elongation has occurred in the backup cables 16 and 17 (step S54 → step S55).

  As described in the first embodiment, in the steer-by-wire system, the steering handle 1 can be rotated by passing an electric current through the reaction force motor 4, but in the state where the backup clutch 6 is connected, the backup cable 16 , 17 is not fully extended, the steering wheel 1 stops rotating. At this time, the torque generated in the reaction force motor 4 is transmitted to the steered torque sensor 19 via the backup cables 16 and 17, and a torque value is output. This torque value is a small value until the backup cables 16 and 17 are fully extended, and becomes a large value when the backup cables 16 and 17 are fully extended. By monitoring whether the steering torque value exceeds a certain threshold, It can be determined whether the backup cables 16 and 17 are extended. The extension amount of the backup cables 16 and 17 can be estimated from the angle of the steering handle 1 at this time.

As described above, in Example 3, when the backup cables 16 and 17 are fully extended, the torque generated in the reaction force motor 4 is transmitted to the steering torque sensor 19 via the backup cables 16 and 17 and the steering torque is increased. Since the method using the characteristics is adopted, the extension amount of the backup cables 16 and 17 can be accurately estimated.
The steered torque sensor 19 is a sensor provided for detecting road disturbances in the steer-by-wire system, so there are no additional parts for estimating the amount of extension of the backup cables 16, 17. It is also useful in terms of cost.

Next, the effect will be described.
In the vehicle steering control device of the third embodiment, in addition to the effects (1), (2), and (3) of the first embodiment, the following effects can be obtained.

  (6) A turning torque sensor 19 (steering torque detecting means) for detecting the turning torque of the turning actuator 11 is provided, and the cable elongation determining means is provided when the steering portion is rotated by the reaction force motor 4. When the turning torque exceeds a predetermined value, it is determined that the cable has been fully extended (steps S48 and S51). Therefore, when the cable is fully extended, the torque generated in the reaction force motor 4 is the turning torque via the cable. By using the characteristic that the turning torque is rapidly increased by being transmitted to the sensor 19, it is possible to accurately determine whether the cable has been fully extended.

  The fourth embodiment is an example in which immediately after the engine is started, the electric power steering mode is set in a state where the backup clutch 6 is connected, and the extension determination of the backup cables 16 and 17 is performed based on the steering torque. In addition, since it is the same as that of FIG.1 and FIG.2 of Example 1 in structure, illustration and description are abbreviate | omitted.

Next, the operation will be described.
[Cable elongation judgment processing]
FIG. 8 is a flowchart showing the flow of cable elongation determination processing executed in the steer-by-wire system (for example, the steering control device 10) of the fourth embodiment. Each step will be described below (cable elongation determination means).

  In step S61, it is determined whether or not the driver has turned on the key to start the engine. If Yes, the process proceeds to step S62, and if No, the process proceeds to the end.

  In step S62, following the key ON determination in step S61, it is determined whether or not the extension amount determination of the backup cables 16 and 17 has been completed. If Yes, the process proceeds to step S72. If No, step S63 is performed. Migrate to

  In step S63, following the determination that the cable extension amount determination has not been completed in step S62, with the backup clutch 6 still connected, the steering motor 9 is used as an assist means to assist the steering torque input to the steering handle 1 with power assist. The power steering mode is started and the process proceeds to step S64.

In step S64, following the start of the electric power steering mode in step S63, the driver steers the steering wheel 1 to the right and determines whether the steering torque exceeds the + threshold value. If No, the process moves to step S66.
Here, the + threshold and the −threshold described later are determined by measuring the steering torque when the backup cables 16 and 17 are fully extended in advance. Alternatively, it is determined from the cable tension characteristics.

  In step S65, following the determination of steering torque> + threshold value in step S64, the difference between the steering wheel angle and the turning angle at that time is calculated and set as the difference angle during right steering, and the process proceeds to step S66.

  In step S66, following the determination of steering torque ≦ + threshold in step S64, or the difference angle calculation during right steering in step S65, the driver steers the steering handle 1 to the left side, and the steering torque is -It is determined whether or not it is less than the threshold value. If Yes, the process proceeds to step S67. If No, the process proceeds to step S68.

  In step S67, following the determination of steering torque <-threshold value in step S66, the difference between the steering wheel angle and the turning angle at that time is calculated and set as the difference angle during left steering, and the process proceeds to step S68.

  In step S68, following the determination that steering torque ≧ −threshold in step S66, or the difference angle calculation during left steering in step S67, it is determined whether the difference angle during left and right steering is calculated. If Yes, the process proceeds to step S69. If No, the process returns to step S64 to repeat each determination and calculation.

  In step S69, following the determination in step S68 that the difference angle calculation during left and right steering is complete, the sum of the difference angle during right steering and the difference angle during left steering (= add the absolute value of both difference angles). The combined angle) is calculated and used as the extension amount of the backup cables 16 and 17, and the process proceeds to step S70.

  In step S70, following the calculation of the backup cable elongation amount in step S69, an allowable range in which the performance of the system can be guaranteed in consideration of the expansion amount of the backup cables 16 and 17 including the aging deterioration in the normal use range. It is determined whether or not the number is exceeded. If Yes, the process proceeds to step S71. If No, the process proceeds to step S72.

  In step S71, following the determination that the cable extension amount in step S70 is within the allowable range, it is determined that the backup cables 16 and 17 are abnormally stretched, the abnormality is warned with a warning lamp or the like, and steer-by-wire. The normal power control is not started, and the electric power steering mode is continued as it is.

  In step S72, following the determination of the end of cable extension determination in step S62 or the cable normality determination in step S71, the backup clutch 6 is disconnected and steering control (normal control) by steer-by-wire is started.

[Cable elongation judgment]
In the fourth embodiment, in the steer-by-wire system in which the backup clutch 6 is connected when the system fails and the steering is performed by the backup cables 16 and 17, the torque sensor 2 connected in the vicinity of the steering handle 1 is connected to the backup clutch 6. The steering motor 9 is driven in a direction to decrease the steering torque signal measured in step S1 to enter an electric power steering state that assists the steering force steered by the driver, and the steering angle, steering handle angle, and steering torque at that time Cable extension amount determination means for determining the extension amount of the backup cables 16 and 17 based on the amount is provided.

As shown in the flowchart of FIG. 8, the cable extension amount determination means obtains the difference between the steering angle and the steering wheel angle when the steering torque when the driver steers to the right exceeds the + threshold value (step S64). → Step S65) Further, the difference between the steering angle and the steering wheel angle when the steering torque when the driver opposite to this steers to the left becomes less than the −threshold is obtained (Step S66 → Step S67). The angle obtained by adding the absolute values of the angles of the two differences is defined as the extension amount of the backup cables 16 and 17 (step S69).
When the amount of elongation exceeds the normal range set in advance including the secular change, it is determined that abnormal elongation has occurred in the backup cables 16 and 17 (step S70 → step S71).

  In the electric power steering state in which the backup cables 16 and 17 are connected, as shown in FIG. 9A, in a region where the steering torque is small until the driver steers the steering wheel 1 and the backup cables 16 and 17 are fully extended. Even if the steering handle 1 is steered, the steered actuator 11 side does not move so much, so the difference between the steering handle angle and the steered angle greatly increases or decreases according to the steering. When the backup cables 16 and 17 are fully extended, the difference between the steering wheel angle and the steering angle hardly increases even if the steering torque increases.

Therefore, the steering torque at which the backup cables 16, 17 are fully extended is measured in advance (cable extension A in FIG. 9A), and compared with the actual steering torque, the backup cables 16, 17 are extended. You can judge whether or not.
Furthermore, the difference between the steering wheel angle and the turning angle when it is determined that the backup cables 16 and 17 are fully extended can be estimated as the extension amount of the backup cables 16 and 17. However, since the extension amount of the backup cables 16 and 17 detected only by steering to one side is half of the original extension amount, the extension amounts of the backup cables 16 and 17 are similarly determined when steering to the opposite side. Then, the difference between the steering wheel angle and the turning angle at that time is obtained. And if the angle difference at the time of left-right steering is calculated | required, the sum will become original backup cable elongation amount.

As described above, in the fourth embodiment, when the backup cables 16 and 17 are fully extended in the electric power steering state, the difference between the steering wheel angle and the steering angle hardly increases even when the steering torque increases. Since the method using is used, the amount of extension of the backup cables 16 and 17 can be accurately estimated.
Note that the torque sensor 2 for detecting the steering torque, the steering handle angle sensor 3 and the turning angle sensor 8 are necessary for basic control of the steer-by-wire system and are always provided. There are no parts added to estimate the quantity, which is also useful in terms of cost.

  If the sum of the deviations of the steering wheel angle and the turning angle at the time of left and right steering is obtained from the normal extension amount of the backup cables 16 and 17 (the extension amount A of the cable in FIG. 9A), the right and left by the driver By comparing the sum of the deviation between the steering wheel angle and the turning angle during steering (cable extension B in FIG. 9A), the extension of the backup cables 16 and 17 is within an allowable range (FIG. 9B). It is possible to determine whether it is within (OK range).

  In the first to third embodiments, the extension amount of the cable is determined based only on the steering wheel angle. However, the steering actuator 11 does not operate when the extension amount of the backup cables 16 and 17 is determined. This is because of this (FIG. 10 (a)). As in the fourth embodiment, in the electric power steering state, the reference turning angle always changes as the turning actuator 11 operates according to the steering torque, and therefore, from the difference between the steering handle angle and the turning angle. The amount of extension of the backup cables 16 and 17 is determined (FIG. 10B).

  Therefore, in the fourth embodiment, the full function of the steer-by-wire (variable gear, etc.) in the electric power steering state is not possible, but the extension amount of the cable can be determined during the normal steering by the driver. Since no special operation is required for diagnosing the cable extension amount, the driver's steering is not limited for the cable extension amount diagnosis.

Next, the effect will be described.
In the vehicle steering control device of the fourth embodiment, in addition to the effects (1) and (2) of the first embodiment, the following effects can be obtained.

(7) A steering handle angle sensor 3 (steering rotation angle detecting means) for detecting the steering handle angle of the steering handle 1 and a turning angle sensor 8 (detecting a turning angle) for detecting the turning angle of the turning actuator 11. And the cable extension determining means is configured such that a deviation between a steering wheel angle and a turning angle when it is determined that the cable is fully extended when left-steered, and a cable is When the sum of the deviation between the steering wheel angle and the turning angle when it is determined that the cable is fully extended is greater than or equal to a predetermined value, it is determined that an abnormality in cable extension has occurred. Even in the vehicle conditions in which the turning angle always changes as a result of the operation of No. 11, the abnormality determination of the cable extension amount can be performed with high accuracy.

  (8) A torque sensor 2 (steering torque detecting means) for detecting the steering torque of the driver input to the steering handle 1 is provided, and the cable extension determining means is configured to detect when the steering torque becomes a predetermined value or more. In order to determine that the cable has been fully extended, in the electric power steering state, when the backup cables 16 and 17 are fully extended, the characteristic that the steering torque increases rapidly is used to accurately determine whether the cable has been fully extended. be able to.

  As mentioned above, although the vehicle steering control apparatus of the present invention has been described based on the first to fourth embodiments, the specific configuration is not limited to these first to fourth embodiments, and Design changes and additions are permitted without departing from the spirit of the invention according to each claim of the scope.

In Example 1, an example of determining the cable is Tsu Ki extended by the reaction force motor current, in the second embodiment, an example of determining the cable is Tsu Ki extended by the difference between the target steering wheel angle and the actual steering wheel angle shows, in example 3, an example of determining the cable is Tsu Ki extended by turning torque, in the fourth embodiment, an example of determining the cable is Tsu Ki extended by the steering torque. However, the present invention is not limited to the first to fourth embodiments. In short, when the steering unit is rotated left or right by the steering reaction force actuator or the driver, the cable is extended based on a parameter relating to the force for rotating the steering unit. If there is provided cable extension determination means for determining whether or not an abnormality in cable extension has occurred based on the rotational position of the steering unit when it is determined that the cable has been fully extended Are included in the present invention.

  In the first to fourth embodiments, the vehicle steering control device using the steer-by-wire system including the backup cable mechanism is shown. However, the steering unit and the steered unit are always mechanically connected via the cable without the backup clutch. The present invention can also be applied to the vehicle steering control device. In short, the present invention can be applied to a vehicle steering control device including a cable column unit that mechanically connects a steering unit operated by a driver and a steering unit that steers steered wheels with a cable.

1 is an overall system diagram illustrating a vehicle steering control apparatus according to a first embodiment. It is a top view which shows the backup cable mechanism of the steering control apparatus for vehicles of Example 1. FIG. It is a flowchart which shows the flow of the cable elongation determination process performed in the steer-by-wire system of Example 1. It is a relationship figure with the steering wheel angle when an electric current is sent through the reaction force motor in the cable elongation determination of the first embodiment. It is a flowchart which shows the flow of the cable elongation determination process performed in the steer-by-wire system of Example 2. FIG. 10 is a relationship diagram between a steering wheel angle and (command angle−actual steering wheel angle) in cable extension determination according to the second embodiment. 12 is a flowchart illustrating a flow of cable extension determination processing executed in the steer-by-wire system according to the third embodiment. It is a flowchart which shows the flow of the cable elongation determination process performed in the steer-by-wire system of Example 4. FIG. 10 is a relationship diagram between steering torque and (steering handle angle−steering angle) in cable extension determination of the fourth embodiment. It is a figure explaining how to obtain | require the angle which estimates the backup cable elongation amount in Example 4. FIG.

Explanation of symbols

1 Steering handle (steering part)
2 Torque sensor (steering torque detection means)
3 Steering wheel angle sensor (steering rotation angle detection means)
4 Reaction force motor (steering reaction force actuator)
5 Reaction force control device 6 Backup clutch 7 Backup cable mechanism (cable column section)
8 Steering angle sensor (steering angle detection means)
9 Steering motor 10 Steering control device 11 Steering actuator (steering part)
12 Steering wheel 13 Communication line 14 Pulley 15 Case 16 Inner cable (cable)
17 Outer cable (cable)
18 Tension adjusting spring 19 Steering torque sensor (steering torque detection means)

Claims (9)

In a vehicle steering control device including a cable column unit that mechanically connects a steering unit operated by a driver and a steering unit that steers steered wheels with a cable,
Wherein when the steering unit is rotated to the left and right, the steering unit based on a parameter related to the force for rotating the determines whether or not the cable fully extended, the steering portion when it is determined that the cable is fully extended A vehicle steering control device comprising: a cable extension determining unit that determines whether or not an abnormality in cable extension has occurred based on a rotational position. The vehicle steering control device according to claim 1,
A steering rotation angle detecting means for detecting a steering rotation angle of the steering unit is provided;
The cable extension determining means has the steering rotation angle when it is determined that the cable is fully extended when the steering part is rotated counterclockwise, and the cable is extended when the steering part is rotated clockwise. When the deviation from the steering rotation angle at the time of determination is greater than or equal to a predetermined value, it is determined that an abnormality in cable extension has occurred. The vehicle steering control device according to claim 1,
A steering rotation angle detection means for detecting a steering rotation angle of the steering section, and a turning angle detection means for detecting a turning angle of the steering section;
The cable extension determining means determines a deviation between the steering rotation angle and the turning angle when it is determined that the cable is fully extended when the steering unit is rotated counterclockwise, and the steering unit is rotated clockwise. When the difference between the steering rotation angle and the turning angle when it is determined that the cable is fully extended is greater than or equal to a predetermined value, it is determined that an abnormality in cable extension has occurred. A vehicle steering control device. The vehicle steering control device according to any one of claims 1 to 3,
A steering reaction force actuator for applying a steering reaction force to the steering unit;
The vehicular steering control device, wherein the cable extension determining means rotates the steering unit by the steering reaction force actuator. In the vehicle steering control device according to claim 4,
Providing a current detection means for detecting a current of the steering reaction force actuator;
The vehicle steering control device, wherein the cable extension determining means determines that the cable has been extended when the current value becomes a predetermined value or more. In the vehicle steering control device according to claim 4,
A steering rotation angle detecting means for detecting a steering rotation angle of the steering unit is provided;
The cable extension determining means determines that the cable has been extended when a deviation between a target rotation angle when the steering unit is rotated by the steering reaction force actuator and the steering rotation angle is a predetermined value or more. A vehicle steering control device. In the vehicle steering control device according to claim 4,
A steering torque detecting means for detecting a steering torque of the steering unit;
The cable extension determining means determines that the cable is fully extended when the turning torque when the steering unit is rotated by the steering reaction force actuator becomes a predetermined value or more. Steering control device. The vehicle steering control device according to any one of claims 1 to 3,
A steering torque detecting means for detecting the steering torque of the driver input to the steering section is provided;
The vehicle steering control device, wherein the cable extension determining means determines that the cable has been extended when the steering torque becomes a predetermined value or more. In a vehicle steering control device including a cable column unit that mechanically connects a steering unit operated by a driver and a steering unit that steers steered wheels with a cable,
Wherein when the steering unit is rotated to the left and right, the steering unit based on a parameter related to the force for rotating the determines whether or not the cable fully extended, the steering portion when it is determined that the cable is fully extended A vehicle steering control device that determines whether or not an abnormality in cable extension has occurred based on a rotational position.

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