JP2006182057A - Steering system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering system for a vehicle capable of positively inhibiting a steering operation if an illegal access is made. <P>SOLUTION: This steering system for a vehicle is provided with a steering input device for inputting the amount of steering by a driver and a steering device for performing switching between the first state of steering a steered wheel in accordance with the amount of steering input in the steering input device and a second state of inhibiting steering of the steered wheel in accordance with the amount of steering input in the steering input device. In the steering system, if it is detected that an illegal access is made to the vehicle, the steering device is maintained in the second state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle steering apparatus, and particularly to a vehicle antitheft technique that makes it difficult for a driver to perform a steering operation when an unauthorized access is made to the vehicle.

As this type of vehicle steering apparatus, a technique described in Patent Document 1 is disclosed. In this publication, when it is recognized that an unauthorized access has been made in a vehicle steering device in which a variable steering angle mechanism capable of changing the transmission ratio between the steering wheel steering amount and the steered wheel steering amount is arranged, The transmission ratio by the variable rudder angle mechanism is set to an exceptional value that makes it difficult for the driver to perform the steering operation. Thus, the vehicle is prevented from being stolen.
JP 2004-58876 A

  However, in the above prior art, although the transmission ratio by the variable steering angle mechanism is set to an exceptional value so that the driver's steering operation becomes difficult, the steering wheel and the steering wheel are physically connected. Therefore, although it is difficult to steer, it is not in a state where steering is not completely possible, and there is a possibility that the vehicle can be moved. In addition, a conventional technique provided with a lock mechanism or the like is also known, but when the lock mechanism is broken, it is still in a steerable state.

  The present invention has been made paying attention to the above-mentioned problem, and the object of the present invention is to provide a vehicle steering apparatus capable of reliably making a steering impossible state when it is recognized that unauthorized access has been made. It is to provide.

  In order to achieve the above object, in the present invention, a steering input means for inputting the steering amount of the driver, a first state in which the steered wheels are steered according to the steering amount input to the steering input means, Steering means capable of switching between a second state in which steering of the steered wheels cannot be steered according to a steering amount input to the steering input means, Detecting means for detecting whether or not unauthorized access has been made, and antitheft means for maintaining the turning means in the second state when the detecting means detects that unauthorized access has been made. It is characterized by that.

  In the vehicle steering device of the present invention, when unauthorized access is performed, steering of the steered wheels according to the steering amount input to the steering input means is disabled, so that steering is surely performed. It becomes possible to disable the steering of the wheel and prevent theft of the vehicle.

  Hereinafter, an embodiment for realizing a vehicle steering system of the present invention will be described based on an example shown in the drawings.

  FIG. 1 is an overall system diagram illustrating a vehicle steering apparatus according to a first embodiment. The vehicle steering apparatus according to the first embodiment is an example of a steer-by-wire (SBW) system including a backup mechanism.

  First, the configuration will be described. As a steering input means for a driver to input a steering amount, a steering wheel 1 and a steering shaft 2 rotatably supported on the vehicle body side and connected to the steering wheel 1 are provided. On the steering shaft 2, a steering angle sensor 8 that detects a steering angle as a steering amount of the driver and a steering torque sensor 9 that detects a steering torque as a steering amount of the driver are provided.

  The steering wheel 1 incorporates an air bag mechanism as a collision safety device. One end of the airbag mechanism is fixed to the vehicle body side and wound around the outer periphery of the steering shaft 2 with a margin, and the other end is fixed to the steering wheel 1 (or the steering shaft 2) and controlled by the airbag mechanism. A spiral cable 16 capable of outputting signals and the like is provided.

  Further, the steering wheel 20 side of the steering angle sensor 8 and the steering torque sensor 9 has a reaction force motor 3 that applies a steering reaction force to the driver (the steering wheel 1). The reaction force motor 3 includes a resolver 10 that detects a motor rotation angle of the reaction force motor 3. On the steered wheel 20 side with respect to the reaction force motor 3, an electromagnetic clutch 6 capable of physically engaging and releasing between the steering shaft 2 and the backup mechanism 7 is provided.

  The backup mechanism 7 includes a steering-side cable pulley 7a having one end connected to the electromagnetic clutch 6, a steered-wheel-side cable pulley 7b having one end connected to the pinion shaft 15, and both cable pulleys 7a and 7b in opposite directions. The two cables 7c and 7d are connected in a state of being wound around. When the electromagnetic clutch 6 is released, the rotation of the steering shaft 2 is not transmitted to the pinion shaft 15. On the other hand, when the steering wheel 1 is rotated in one direction while the electromagnetic clutch 6 is engaged, one of the two cables 7c and 7d transmits a steering torque input from the driver, The other cable is configured to exhibit a function equivalent to that of the column shaft by transmitting a reaction torque input from the steering wheel 20.

  As a turning means for turning the steered wheel 20, the pinion shaft 15 is rotatably supported on the vehicle body side and connected at one end to the steered wheel side cable pulley 7b. The pinion shaft 15 includes two steered motors 5 and 5 that output a steering torque to the pinion shaft 15, resolvers 11 and 11 that detect a rotation angle of the steered motor 5, the steered motor 5, and a steered wheel. And a turning torque sensor 12 for detecting the rotational torque of the pinion shaft 15 and a rotary encoder 13 for detecting the rotational angle of the pinion shaft 15. A rack and pinion mechanism (not shown) is provided at the steered wheel side end of the pinion shaft 15, and the steered wheel 20 is steered by moving the steering rack 4 in the axial direction.

  FIG. 2 is a block diagram showing the configuration of the control unit 14. The control unit 14 includes a steering angle detected by the steering angle sensor 8, a steering torque detected by the steering torque sensor 9, a reaction motor rotation angle detected by the resolver 10, and a turning motor rotation angle detected by the resolver 11. , Turning torque detected by the turning torque sensor 12, pinion shaft rotation angle detected by the rotary encoder 13, sensor signals of other sensors (vehicle speed sensor, yaw rate sensor, lateral acceleration sensor, etc.), illegal to the vehicle An unauthorized access signal or the like is input from the vehicle security system 30 that monitors access.

  In the control unit 14, a steer-by-wire control unit 141 that steers the steered wheels 20 by the steered motor 5 based on operation amounts and various sensor values when the driver operates the steering wheel 1, and an electromagnetic clutch 6, a clutch control unit 142 that controls the engagement / release of 6, an unauthorized access detection unit 143 that detects unauthorized access signals from the vehicle security system 30, and an antitheft control unit that performs antitheft control when unauthorized access is detected. 144.

  The steer-by-wire control unit 141 outputs a control signal to the reaction force motor 3 so as to apply a steering reaction force torque corresponding to the traveling state, and also changes the traveling state and the driver's steering state to the steered motor 5. A control signal is output so as to give a corresponding turning amount. Note that the electromagnetic clutch 6 is disengaged during normal steer-by-wire control execution, and is configured to engage the electromagnetic clutch 6 during ignition OFF or fail-safe control.

  FIG. 3 is a flowchart illustrating the anti-theft control process according to the first embodiment. This control flow is executed as an initial process when the ignition is turned on. Further, the electromagnetic clutch 6 is engaged when the ignition is OFF, and after completion of the initial process, the electromagnetic clutch 6 is released when a predetermined condition is satisfied.

  In step 101, the unauthorized access detection unit 143 accesses the vehicle security system 30 and performs data collation to determine whether unauthorized access has been detected. This data collation is to detect whether or not the vehicle has been infiltrated using a fraudulent key, for example, by collation with an electronic key of a computer.

  In step 102, the unauthorized access detection unit 143 determines whether or not the data collation is OK. If OK, the process proceeds to step 103. Otherwise, the process proceeds to step 105.

  In step 103, the clutch control unit 142 releases the electromagnetic clutch 6.

  In step 104, the steer-by-wire control by the steer-by-wire control unit 141 is started (corresponding to the first state described in the claims).

  In step 105, the clutch control unit 142 releases the electromagnetic clutch 6.

  In step 106, the steer-by-wire control by the steer-by-wire control unit 141 is prohibited (corresponding to the second state described in the claims).

  In step 107, sensor and spiral cable protection processing is executed.

[Sensor and spiral cable protection]
FIG. 4 is a flowchart showing the sensor and spiral cable protection process of the first embodiment.
In step 201, the steering angle θ of the steering angle sensor 8 is read.

  In step 202, the steering angle θ is larger than a value θR obtained by adding a predetermined steering angle to the maximum right steering angle θmax that can be recognized by the steering angle sensor 8 during right steering, and the maximum left steering that the steering angle sensor 8 can recognize during left steering. It is determined whether or not the steering angle θ is smaller than θL obtained by subtracting the predetermined steering angle from the angle θmax, that is, whether or not the steering angle θ is within the range of θR and θL. When it is outside, the process proceeds to step 203.

  In step 203, the reaction force motor 3 applies a reaction force in a direction in which the steering angle θ is in the range of θR and θL, thereby restricting the movement of the steering wheel 1.

[Operation of anti-theft control processing]
Next, the operation of the antitheft control process will be described. If the unauthorized access detection unit 143 determines that the data verification is OK, the electromagnetic clutch 6 is released and steer-by-wire control is executed. On the other hand, when unauthorized access is detected by data collation, the clutch control unit 142 releases the electromagnetic clutch 6 (because the electromagnetic clutch 6 is engaged when the ignition is OFF). Next, the steer-by-wire control by the steer-by-wire control unit 141 is prohibited.

  Thus, when unauthorized access is detected, even if the steering wheel 1 is operated, the electromagnetic clutch 6 is released, so that it is impossible to steer the steered wheels 20 by the driver's steering, It is possible to reliably prevent theft. In steer-by-wire control, the steering wheel 1 and the steering wheel 20 are basically controlled in a physically separated state. Therefore, even if the steering wheel 1 is operated by prohibiting steer-by-wire control. Steering control is not performed.

  Next, the operation of the sensor and spiral cable protection process will be described. A steering shaft 2 connected to the steering wheel 1 is provided with a steering angle sensor 8 and a spiral cable 16 of an air bag mechanism. When the steering angle sensor 8 is steered beyond a steering angle range that can be recognized by the steering angle sensor itself, the steering angle sensor 8 recognizes a failure state as an impossible state and can operate normally even if unauthorized access is resolved. It becomes difficult.

  Further, the spiral cable 16 of the air bag mechanism is wound so as not to be caught within a range where the steering wheel 1 is operated during normal traveling. In other words, if the steering wheel 1 is operated beyond that range, the spiral cable 16 may be caught and may break. Also in this case, it is difficult to operate normally when unauthorized access is resolved.

  In other words, if the electromagnetic clutch 6 is simply released when unauthorized access is detected, basically there is nothing to constrain the rotation of the steering shaft 2, so that it rotates freely. There is a risk of breaking. Therefore, the steering angle θ is read from the steering angle sensor 8 and when the steering angle θ exceeds the range of θR and θL, the reaction force motor 3 regulates the movement of the steering wheel 1. Accordingly, theft prevention control can be performed without causing a failure of the sensor or the like or breaking of the spiral cable 16. Needless to say, when the steering angle θ again falls within the range of θR and θL, the steering is prohibited by releasing the electromagnetic clutch 6.

  As described above, the vehicle steering apparatus according to the first embodiment has the following effects.

  (1) When the unauthorized access detection unit 143 detects unauthorized access, the electromagnetic clutch 6 is released, and the anti-theft control unit 144 prohibits steer-by-wire control. That is, the steering amount of the steering wheel 1 cannot be transmitted to the steering wheel 20. Therefore, it becomes impossible to steer the steered wheel 20 by operating the steering wheel 1, and it is possible to reliably prevent theft.

  (2) When the steering angle θ detected by the steering angle sensor 8 exceeds the detectable range (θR to θL) of the steering angle sensor 8 when the electromagnetic clutch 6 is released by the anti-theft control unit 144 Decided to regulate the movement of the steering wheel 1. Therefore, theft prevention control can be performed without causing a failure of the steering angle sensor 8 or the like, or breaking of the spiral cable 16.

  (3) The reaction force motor 3 applies the reaction force in the direction in which the steering angle θ falls within the detectable range (θR to θL) of the steering angle sensor 8. Therefore, the movement of the steering wheel 1 can be restricted while the electromagnetic clutch 6 is released.

  Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. In the first embodiment, the electromagnetic clutch 6 is disconnected during normal steering control and steer-by-wire control is performed. On the other hand, in the second embodiment, during normal steering control, the electromagnetic clutch 6 is always engaged, and steering is performed by a so-called cable-type column system in which steering is performed via the backup mechanism 7.

  FIG. 5 is a block diagram showing the configuration of the control unit 14. Instead of the steer-by-wire control unit 141 of the first embodiment, a steering control unit 150 is provided. FIG. 6 is a block diagram illustrating the configuration of the steering control unit 150. The steering control unit 150 includes a reaction force motor control unit 151 that controls the reaction force motor 3 based on sensor signals of the steering torque sensor 12 and the vehicle speed sensor, and the sensor signal and reaction force motor 3 of the steering torque sensor 9. The cable pulley torque calculation unit 152 calculates the cable torque of the cable pulleys 7a and 7b based on the torque of the steering wheel 5 and the turning motor control unit 153 that controls the steering motor 5 based on the cable pulley torque.

  When the driver operates the steering wheel 1, the relationship between the steering angle of the steering wheel 1 and the rotation angle of the pinion shaft 15 is uniquely determined. At this time, the control amount of the reaction force motor 3 is determined based on the value of the steering torque sensor 12. Next, the sensor value of the steering torque sensor 9 is output as a value obtained by adding the reaction force torque from the reaction force motor 3 and the cable pulley torque of the steering side cable pulley 7a. On the other hand, the sensor value of the turning torque sensor 12 is output as a value obtained by adding the cable pulley torque of the steered wheel side cable pulley 7 b and the turning torque of the turning motor 5. Since the input / output torques of the cable pulleys 7a and 7b have a certain relationship, the control amount of the steered motor 5 is calculated based on the steering torque, the reaction force torque of the reaction force motor 3, and the steering torque. Acts as a mechanism.

  FIG. 7 is a flowchart illustrating an anti-theft control process according to the second embodiment. This control flow is executed as an initial process when the ignition is turned on. Further, it is assumed that the electromagnetic clutch 6 is engaged when the ignition is OFF.

  In step 301, the unauthorized access detection unit 143 accesses the vehicle security system 30 and performs data collation to determine whether unauthorized access has been detected. This data collation is to detect whether or not the vehicle has been infiltrated using a fraudulent key, for example, by collation with an electronic key of a computer.

  In step 302, the unauthorized access detection unit 143 determines whether or not the data collation is OK. If OK, the process proceeds to step 303. Otherwise, the process proceeds to step 305.

  In step 303, the clutch control unit 142 maintains the engagement of the electromagnetic clutch 6.

  In step 304, steering control by the steering control unit 150 is started (corresponding to a first state described in the claims).

  In step 305, the clutch control unit 142 releases the electromagnetic clutch 6.

  In step 306, the steering control by the steering control unit 150 is prohibited, and the steered position is fixed by the steered motor 5 (corresponding to the second state described in the claims).

  In step 307, sensor and spiral cable protection processing is executed.

[Sensor and spiral cable protection]
FIG. 8 is a flowchart showing the sensor and spiral cable protection process of the second embodiment.
In step 401, the steering angle θ of the steering angle sensor 8 is read.

  In step 402, the steering angle θ is larger than a value θR obtained by adding a predetermined steering angle to the maximum right steering angle θmax that can be recognized by the steering angle sensor 8 during right steering, and the maximum left steering that the steering angle sensor 8 can recognize during left steering. It is determined whether or not the steering angle θ is smaller than θL obtained by subtracting the predetermined steering angle from the angle θmax, that is, whether or not the steering angle θ is within the range of θR and θL. Advances to step 403.

  In step 403, the reaction force motor 3 applies a reaction force in the direction in which the steering angle θ is in the range of θR and θL, thereby restricting the movement of the steering wheel 1.

  In step 404, it is determined whether or not the detected value T of the steering torque sensor 9 is larger than the value To difficult to regulate by only the reaction force motor 3. If it is larger, the process proceeds to step 405. Otherwise, the process proceeds to step 406. .

  In step 405, the electromagnetic clutch 6 is engaged.

  In step 406, the electromagnetic clutch 6 is released.

[Operation of anti-theft control processing]
Next, the operation of the antitheft control process will be described. When the unauthorized access detection unit 143 determines that the data verification is OK, the electromagnetic clutch 6 is released and the steering control is executed. On the other hand, when unauthorized access is detected by data collation, since the electromagnetic clutch 6 is engaged when the ignition is OFF, first, the clutch control unit 142 releases the electromagnetic clutch 6. Next, the steering control by the steering control unit 150 is prohibited, and the turning angle of the turning motor 5 is fixed. The turning angle may be fixed to maintain the initial turning position when the ignition is on, or may be fixed at the turning position to the left or right maximum turning angle. Well, not particularly limited.

  Thus, when unauthorized access is detected, even if the steering wheel 1 is operated, the electromagnetic clutch 6 is released, so that it is impossible to steer the steered wheels 20 by the driver's steering, It is possible to reliably prevent theft.

  Next, the operation of the sensor and spiral cable protection process will be described. In the first embodiment, the reaction motor 3 regulates the movement of the steering wheel 1. In Example 2, since the steered position of the steered motor 5 is further fixed, the electromagnetic clutch 6 is engaged when the torque detected by the steering torque sensor 9 becomes a value that is difficult to be regulated only by the reaction force motor 3. . Thereby, in addition to the torque of the reaction force motor 3, the movement of the steering wheel 1 can be regulated using the torque of the steering motor 5.

  As described above, the vehicle steering apparatus of the second embodiment has the following operational effects in addition to the operational effects described in (1) to (3) of the first embodiment.

  (4) The anti-theft control unit 144 fixes the steered motor 5 at a predetermined position and fixes the steered wheel 20 at a predetermined state. Therefore, it becomes possible to make it difficult for the vehicle to move, and it is possible to prevent theft.

  (5) The anti-theft control unit 144 fixes the steering wheel 1 by the torque of both the reaction force motor 3 and the steered motor 5 when the electromagnetic clutch 6 is engaged. Thereby, when the steering angle θ exceeds the detectable range (θR to θL) of the steering angle sensor 8, the movement of the steering wheel 1 can be more reliably regulated.

(Other examples)
As mentioned above, although the vehicle steering device of the present invention has been described based on the first and second embodiments, the specific configuration is not limited to the first and second embodiments, and each claim of the claims Design changes and additions are allowed without departing from the gist of the invention.
For example, in the first and second embodiments, the steer-by-wire control is executed when unauthorized access is not detected. However, the assist torque is increased according to the steering torque of the driver while the electromagnetic clutch 6 is engaged. You may make it perform the power assist control which controls the steering motor 5 and the reaction force motor 3 so that it may provide.

  For example, although the electromagnetic clutch 6 is used in the first embodiment, a friction clutch may be used. In the first and second embodiments, the cable type column is used. However, other configurations may be used as long as the relationship between the steering wheel 1 and the steering wheel 20 can be physically connected and disconnected.

  In the first embodiment, the position of the steering wheel 1 is restricted by the reaction force motor 3. However, when it is difficult to restrict the position of the steering wheel 1 only by the reaction force motor 3, the electromagnetic clutch 6 is temporarily turned on as in the second embodiment. It may be fastened and regulated using the reaction torque of the steering motor 5.

  In the second embodiment, the steering angle of the steered wheel is fixed by the steered motor 5. However, as in the first embodiment, the electromagnetic clutch 6 may be simply released and the steered wheel 20 may not be fixed. .

1 is an overall system diagram illustrating a vehicle steering apparatus according to a first embodiment. FIG. 3 is a block diagram illustrating a configuration of a control unit according to the first embodiment. 3 is a flowchart illustrating an anti-theft control process according to the first embodiment. It is a flowchart showing the sensor and spiral cable protection process of Example 1. FIG. 6 is a block diagram illustrating a configuration of a control unit according to a second embodiment. FIG. 6 is a block diagram illustrating a configuration of a steering control unit according to a second embodiment. 6 is a flowchart illustrating an anti-theft control process according to a second embodiment. It is a flowchart showing the sensor and spiral cable protection process of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Reaction force motor 4 Steering rack 5 Steering motor 6 Electromagnetic clutch 7 Backup mechanism 8 Steering angle sensor 9 Steering torque sensor 12 Steering torque sensor 13 Rotary encoder 14 Control unit 15 Pinion shaft 16 Spiral cable 20 Facing wheel 30 Vehicle security system

Claims (7)

Steering input means for inputting the steering amount of the driver;
The first state in which the steered wheels are steered according to the steering amount input to the steering input means, and the steered wheels to be steered according to the steer amount input to the steering input means are disabled. Steering means capable of switching between the second state;
In a vehicle steering apparatus provided with
Detection means for detecting whether unauthorized access to the vehicle has been made,
An anti-theft means for maintaining the steered means in the second state when it is detected by the detecting means that unauthorized access has been made;
A vehicle steering apparatus comprising: The vehicle steering apparatus according to claim 1,
The steering means is provided with fastening means that can be physically fastened and released with the steering input means,
In the second state, the vehicle steering apparatus is characterized in that the fastening means is released. The vehicle steering apparatus according to claim 1 or 2,
The anti-theft means fixes the steering position of the steered wheels by the steering means. The vehicle steering apparatus according to any one of claims 1 to 3,
Steering amount detection means for detecting the steering amount of the driver;
If the steering amount detected by the steering amount detection means exceeds the detectable range of the steering amount detection means while maintaining the second state, the steering for restricting the movement of the steering input means Regulatory measures,
A vehicle steering apparatus characterized by comprising: The vehicle steering device according to claim 4,
A reaction force applying means for applying a steering reaction force to the driver is provided,
The vehicle steering apparatus according to claim 1, wherein the steering restricting means applies a reaction force in a direction in which a steering amount falls within the predetermined range by the reaction force applying means. In the vehicle steering device according to claim 4 or 5,
The steering apparatus for a vehicle, wherein the steering restricting means restricts the movement of the steering input means by fastening of the fastening means. Steering input means for inputting the steering amount of the driver;
A first state in which steered wheel turning according to the steering amount input to the steering input means is enabled, and a second state in which the steering amount input to the steering input means cannot be transmitted to the steered wheels Steering means capable of switching between, and
In a vehicle steering apparatus provided with
When it is detected that an unauthorized access to a vehicle has been made, the vehicle steering device is characterized in that the steering means is maintained in the second state.

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