JP5233238B2 - Vehicle steering system - Google Patents

Description

  The present invention belongs to the technical field of a vehicle steering apparatus provided with a clutch that connects a mechanically separated handle and a steering mechanism.

  A conventional vehicle steering system includes a steering wheel operated (steered) by a driver, a steering mechanism mechanically separated from the steering wheel, and a steering motor for driving the steering mechanism. Steer-by-wire control that enables steering by driving the steering mechanism with a steering motor according to the rotation angle (steering angle), and rotating the steering mechanism in the event of an electrical failure The clutch that connects the shaft and the rotating shaft of the handle is engaged (engaged) by engaging the handle, and the handle and the steering mechanism are mechanically connected to enable direct steering by the handle. Have been disclosed (see, for example, Patent Documents 1 and 2).

Also known is a vehicle steering system that shifts from steer-by-wire control to power steering control by mechanically connecting the steering wheel and the steering mechanism by engaging a clutch near the maximum turning angle. (For example, see Patent Document 3).
In other words, steer-by-wire control is performed in which a steering mechanism that is mechanically separated from the steering wheel is driven by a steering motor during normal operation. 2. Description of the Related Art A vehicle steering device that performs power steering control that can be directly steered by a steering wheel with a clutch therebetween is known.
JP 2005-262969 A JP-A-2005-008073 JP 2006-001417 A

  However, in the above prior art, a clutch is used that mechanically connects the steering wheel and the steering mechanism by engaging the rotary shaft of the steering mechanism and the rotary shaft of the handle with an engagement element. Therefore, when shifting from steer-by-wire control to power steering control and then returning to steer-by-wire control again, the clutch engagement state may be maintained even if a clutch release command is output. There is. As described above, when the steering and the steering mechanism are not released and the shift to the steer-by-wire control is performed, a torque that is contrary to the driver's expectation is generated on the steering wheel, so that the steering wheel may be removed. .

  The present invention has been made to solve the above problems, and the object of the present invention is to generate a handle when the clutch is released from the engaged state and the clutch is released to shift to the steer-by-wire control. An object of the present invention is to provide a vehicle steering apparatus that can prevent the above-described problem.

In order to achieve the above object, in the vehicle steering apparatus of the present invention,
A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
With
When the steering control means releases the engagement of the clutch from the engaged state and shifts to the steer-by-wire control, the steering rotation shaft responds to a rotation angle change of the handle rotation shaft. Clutch release control is performed so that the turning mechanism is driven so that a change in the rotation angle of the clutch is reduced, and a rotation deviation angle in the disengagement direction of the clutch is provided between the turning shaft and the steering shaft. It is characterized by that.

  Therefore, in the present invention, since the rotation angle deviation in the clutch disengagement direction is given between the steering rotation shaft and the handle rotation shaft, the torque acting in the clutch engagement direction can be weakened. The engaged clutch is reliably released. As a result, it is possible to prevent the steering wheel from being removed when the clutch is released from the engaged state to shift to the steer-by-wire control.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 5.

First, the configuration will be described.
[System configuration]
FIG. 1 is a configuration diagram of a steer-by-wire (hereinafter referred to as SBW) system to which the vehicle steering apparatus according to the first embodiment is applied.

  The vehicle steering apparatus according to the first embodiment detects a steering handle 1 that can be operated (steered) by a driver, a pulley shaft 79 (handle rotation axis) that is a rotation axis of the steering handle 1 connected to the steering handle 1, and a steering angle. A steering angle sensor 2 (steering angle detection means), a torque sensor 3 for detecting the steering torque of the steering handle 1, a reaction force motor 4 (steering reaction force motor) for applying a reaction force to the steering handle 1, a clutch 5, and steering A right and left front wheel 9 which is a wheel, a rack 8a connected to the left and right front wheel 9 and a pinion 8b connected to the rack 8a by a gear mechanism; Rotation axis), turning angle of the turning motor 6 as a turning actuator for turning the left and right front wheels 9 by driving the turning mechanism 8, and the turning angle of the turning motor 6 (ie, A turning angle sensor 7 (turning angle detection means) for detecting a turning angle), a controller 10, a turning controller 11, and a communication line 12 for performing communication between the controller 10 and the turning controller 11. Yes.

The steering handle 1 and the steering mechanism 8 are mechanically connected or disconnected by engaging / disengaging the clutch 5. The clutch 5 engages the rotating shaft (pulley shaft 79) of the steering handle 1 and the rotating shaft (pinion shaft 17) of the steered mechanism 8 with an engaging element (roller 32; see FIG. 3). And the steering mechanism 8 are mechanically coupled.
The reaction force motor 4 applies a steering reaction force to the steering handle 1, and the steering motor 6 drives the steering mechanism 8 to drive the left and right front wheels 9 (hereinafter simply referred to as front wheels 9).

  The SBW system shown in the first embodiment is configured such that there is no mechanical connection between the steering handle 1 and the steering mechanism 8 connected to the front wheels (steering wheels) 9 at normal times. However, the clutch 5 capable of connecting and disconnecting the pulley shaft 79 and the pinion shaft 17 is provided. By fastening the clutch 5, the pulley shaft 79 and the pinion shaft 17 are connected, and the steering handle 1 and the steering wheel 1 are steered. It is possible to mechanically connect with the mechanism 8.

  A rotation operation of the steering handle 1 is detected by the steering angle sensor 2, and a command turning angle (a command value obtained by converting a target turning angle into a turning angle of the turning motor 6) by a controller (steering control means) 10 is obtained. Calculated. In the turning controller 11, the actual turning angle (the actual turning angle of the turning motor 6 detected by the turning angle sensor 7 and also referred to as the actual turning angle) matches the command turning angle. The drive command value for the steering motor 6 is calculated. The turning operation of the front wheels 9 is performed by driving the turning mechanism 8 by driving the turning motor 6. The steered motor 6 is composed of a brushless motor or the like. The reaction force motor 4 for applying a steering reaction force to the steering handle 1 is composed of a brushless motor or the like, similar to the steering motor 6, and is provided, for example, at the hub portion of the front wheel 9 and input to the front wheel 9. A drive command value is calculated by the controller 10 based on the reaction force detected by the axial force sensor 14 that detects a reaction force (tire lateral force) from the road surface, and the vehicle is driven according to the calculated drive command value. The drive command values calculated by the controller 10 and the turning controller 11 are output as current command values for the reaction force motor 4 and the turning motor 6, respectively.

  The current command value calculated by the turning controller 11 is calculated by an angle servo system that performs control calculation so that the actual turning angle follows the command turning angle with a predetermined response characteristic. This angle servo system is configured by a method using a robust model matching method as shown in FIG. 2, for example. In this method, the model matching compensator 21 calculates a current command value for realizing a predetermined normative response characteristic with respect to the command turning angle, and the robust compensator 22 calculates a compensation current corresponding to the disturbance component. The As a result, it is possible to realize a control system with excellent disturbance resistance in which the actual turning angle can follow the standard response characteristics even when a disturbance occurs.

In the first embodiment, the clutch 5 is disengaged during normal traveling, and SBW control is performed to drive the steering mechanism 8 in accordance with the steering of the steering handle 1, but the turning angle of the front wheel 9 is near the maximum turning angle. When this happens, the clutch 5 is engaged and power steering (hereinafter referred to as EPS) control is performed to drive the steered motor 6 so as to add an auxiliary steering force to the driver's steering force from the steering handle 1. After that, when the driver performs the switchback steering, the clutch 5 is released and the SBW control is resumed.
In the first embodiment, an example is shown in which the clutch 5 is engaged when the turning angle of the front wheels 9 is close to the maximum turning angle, but instead of or in addition to this, for example, in the SBW The clutch 5 may be engaged when an abnormality such as an electric system failure occurs.

[Clutch structure]
FIG. 3 is a cross-sectional view showing a clutch in the vehicle steering apparatus of the first embodiment, and FIG. 4 is a diagram showing a mechanical clutch portion of the clutch in the vehicle steering apparatus of the first embodiment.

  The clutch 5 is a two-way clutch, and is operated by the first rotating member (outer ring 30), the second rotating member (inner ring 31), an excitation unit that generates a magnetic force for connecting and disconnecting the clutch, and the excitation unit. A mechanical clutch portion that connects and disconnects the first rotating member and the second rotating member, and the pulley shaft 79 connected to the steering handle 1 and the pinion shaft 17 of the steering mechanism 8 have a rotational angle change. A rotating member having a mechanical clutch portion is connected to the smaller side.

In the clutch 5, a second rotating member (inner ring 31) having a mechanical clutch portion is connected to the pulley shaft 79.
That is, the pulley shaft 79 is serrated to the inner ring 31. Note that the pinion shaft 17 of the steering mechanism 8 is serrated to the outer ring 30.

  As shown in FIG. 4, the first rotating member is an outer ring 30 having an inner peripheral surface of a cylindrical surface, and the second rotating member is an inner ring 31 having an outer peripheral surface of a cam shape (octagonal shape). The part has a roller 32 (engagement member) interposed between the outer ring 30 and the inner ring 31.

  The clutch 5 allows relative rotation between the outer ring 30 and the inner ring 31 by regulating the roller 32 to a neutral position (regulating the relative position in the rotation direction with respect to the inner ring 31) by the mechanical clutch unit when the excitation unit is operated. When the excitation unit is not in operation, the clutch 32 is wedge-engaged between the outer ring 30 and the inner ring 31 by releasing the neutral position regulation of the roller 32 by the mechanical clutch unit. .

As shown in FIG. 3, the exciting portion is fixed to the end plate 34 (clutch case member) of the clutch case 33 by the serration fitting at the end portion position of the outer ring 30 and the electromagnetic coil 35. And a rotor 37 having permanent magnets 36 disposed in the field.
Note that with the configuration in which the permanent magnet 36 is disposed in the field of the electromagnetic coil 35, an in-phase magnetic flux or a reverse-phase magnetic flux can be applied to the magnetic flux of the permanent magnet 36 by the electromagnetic coil 35.

  As shown in FIG. 3, a plurality of (8) mechanical clutch portions are provided between the armature 39 disposed so as to be axially movable with respect to the rotor 37 via a separation spring 38, and the outer ring 30 and the inner ring 31. There are provided rollers 32 as intervening engagement elements, and a retainer 40 that incorporates a plurality of rollers 32 in a pocket and holds the intervals between the plurality of rollers 32 at equal set intervals. The cage 40 is supported so as to be movable in the rotational direction with respect to the inner ring 31.

  As shown in FIG. 4, the roller 32 is provided with a neutral spring 41 that holds one roller 32 in a neutral position when the clutch is released. During the transition period from the clutch engagement to the release, the outer ring 30 and the inner ring 31 are set. A return spring force to the neutral position is applied to the roller 32 engaged with the wedge. The neutral spring 41 is fixed to the inner ring 31.

A needle bearing 42 (bearing) is provided between the pulley shaft 79 (shaft member) that is serrated and fitted to the inner ring 31 and the rotor 37 that is fixed to the end position of the outer ring 30.
In FIG. 3, the first ball bearing 43 supports the pulley shaft 79 on the end plate 34. The second ball bearing 44 supports the outer ring 30 on the clutch case 33. The third ball bearing 45 is interposed between the outer ring 30 and the inner ring 31.

[Steering control processing]
FIG. 5 is a flowchart showing the flow of the steering control process executed by the controller 10 of the first embodiment, and each step will be described below. This control process is executed every control calculation cycle (for example, 5 msec).

  In step S1, it is determined whether or not the absolute value of the turning angle is equal to or greater than a predetermined value Δf1. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S5. Here, Δf1 is the maximum angle (rack end) at which the turning angle can be physically operated. As the turning angle, a value transmitted from the turning controller 11 to the controller 10 via the communication line 12 is used by reading the output of the turning angle sensor 7 with the turning controller 11. In the following description, communication between the steering controller 11 and the controller 10 is performed via the communication line 12.

  In step S2, as a preparation for shifting to EPS control, an engagement command is output to the clutch 5, and the flow proceeds to step S3.

  In step S3, as a preparation for shifting to EPS control, the reaction force torque output of the reaction force motor 4 is turned off (set to 0), and the output torque of the turning motor 6 is added to the steering force of the driver (auxiliary steering force ( The current command value is calculated based on the value of the torque sensor 3 so as to obtain (steering assist force), and the process proceeds to step S4.

  In step S4, EPS control is executed, and the process proceeds to return. In the EPS control, the current command value of the steered motor 6 calculated based on the value of the torque sensor 3 is calculated and transmitted to the steered controller 11 by communication to realize the EPS operation.

  In step S5, it is determined whether or not EPS control is being performed. If YES, the process proceeds to step S6. If NO, the process proceeds to return.

  In step S6, it is determined whether or not the absolute value of the turning angle is less than a predetermined value Δf2. If YES, the process proceeds to step S7. If NO, the process proceeds to return. Here, δf2 is a value smaller than δf1 (for example, δf1-1 °).

  In step S7, a steering reaction force is applied by the reaction force motor 4 and a steering torque generated by the steering motor 6 is increased by the applied reaction force, and the process proceeds to step S8. That is, the torque generated by the steering motor 6 is increased in the opposite direction by the same amount as the steering reaction force generated by the reaction force motor 4, and the steering reaction force is controlled to be canceled by the torque increase of the steering motor 6. And proceed to step S8.

  In step S8, it is determined whether or not the absolute value of the turning angle is less than a predetermined value Δf3. If YES, the process proceeds to step S9. If NO, the process proceeds to return. Here, δf3 is set to a value smaller than δf2 (for example, δf2-2 °).

  In step S9, it is determined whether or not the steering operation is being switched back. This determination can be made based on whether or not the absolute value of the steering angle detected by the steering angle sensor 2 is continuously decreasing. If YES, the process proceeds to step S10. If NO, the process proceeds to step S2. That is, if the steering is being increased and turned, it is determined that the torque in the engagement direction is acting on the clutch 5, and the process proceeds to step S2. If the steering is being turned back, the clutch 5 is released from the engagement direction. It is determined that torque is acting, and the process proceeds to step S10.

  In step S10, a command turning angle that maintains the turning angle at a predetermined value Δf3 (or −Δf3 when the turning angle is negative) is output, and the process proceeds to step S11.

  In step S11, a clutch release command is output to the clutch 5, and the process proceeds to step S12.

In step S12, it is determined whether the deviation angle between the steering angle and the turning angle is equal to or greater than a predetermined value θ1. If YES, the process proceeds to step S13, and if NO, the process proceeds to return. Here, θ1 is a value set based on the difference between the neutral position and the engagement position of the roller 32, and is a predetermined value.
In step S12, when variable gear control is performed, based on the deviation angle between the steering angle converted to the variable gear ratio (the steering angle × 1.2 in the case of the steering angle ratio 1.2 with respect to the steering angle) and the steering angle. Make a decision.

  In step S13, SBW control is executed, and the process proceeds to return.

Next, the operation will be described.
[Regarding the occurrence of handle removal when the clutch is engaged]
In the conventional SBW system, when any abnormality occurs in the SBW system or when the clutch is engaged near the maximum turning angle, the current of the steering motor that becomes the steering assist force is calculated based on the value of the torque sensor, and the electric power steering A method for realizing a function as an (EPS) apparatus has been proposed.

  In this prior art, it is assumed that after shifting from SBW control to EPS control, returning to SBW control again, it is necessary to release the engaged clutch. At this time, when a two-way clutch as shown in FIGS. 3 and 4 is employed as the clutch, the engaged state may be maintained even if a clutch release command is output, and the clutch may not be released. If the control is shifted to the SBW control as it is, there is a possibility that a so-called handle removal may occur in which a torque that is contrary to the driver's expectation is generated.

  FIG. 6 is a time chart for explaining the reason why the steering wheel is removed, and so-called variable gear control is performed in which the turning angle (pinion shaft conversion angle) is larger than the steering angle during SBW control. Shows the case.

  When the turning angle reaches the maximum turning angle (rack end) that physically moves at time T0, a clutch engagement signal is output and the clutch is engaged, and the control shifts from SBW control to EPS control. As a result, even if the driver tries to further increase the steering wheel, the front wheel and the steering wheel are mechanically connected, so the steering angle does not change and a large steering reaction force can be generated, allowing the driver to recognize the rack end. Can do.

  From this state, when the driver turns the steering wheel back and the turning angle becomes the threshold value 1 (below the maximum turning angle) at time T1, a clutch release command is issued and the EPS control is returned to the SBW control. At this time, if the clutch remains engaged and the clutch is not released, the connection between the front wheel and the steering wheel is maintained, the change in the turning angle and the change in the steering angle become the same, and the torque contrary to the driver's expectation is generated. The handle is attached to the handle.

[Steering control action]
On the other hand, in the vehicle steering apparatus of the first embodiment, when the clutch release command is output, the turning angle (pinion shaft rotation angle) of the front wheels 9 is such that the change in the turning angle of the front wheels 9 becomes small with respect to the change in the steering angle. To control.

  That is, when the clutch 5 is engaged near the maximum turning angle to shift from SBW control to EPS control, the clutch 5 is released when returning to steering, and when returning from EPS control to SBW control again, the flowchart of FIG. In step S1 → step S5 → step S6 → step S7 → step S8 → step S9 → step S10, the steering angle is held at the predetermined value δf3 in step S10, and then a clutch release command is output in step S11. When it is determined in step S12 that the deviation angle between the steering angle and the turning angle is equal to or greater than the predetermined value θ1, the process proceeds to step S13 and SBW control is executed.

As a result, the torque acting in the engagement direction of the clutch 5 can be weakened, and the engaged clutch 5 is surely released. Therefore, when shifting from EPS control to SBW control, the clutch 5 It is possible to prevent the handle from being removed due to the fact that it cannot be released.
As a result, the clutch 5 is engaged in the SBW system using the clutch 5 that is connected by engaging with the engaging member as a clutch that mechanically connects the front wheel steering mechanism 8 and the steering handle 1. The process of shifting from EPS control to SBW control can be performed while reliably canceling the above.

  Further, in the flowchart of FIG. 5, in step S10, the turning angle δf3 at the time of clutch release command output is held, so that the turning angle is fixed and the torque acting only in the engagement direction is weakened. Therefore, the torque acting in the engaging direction can be weakened more quickly, and the engaged clutch 5 is reliably released.

  In Step S12, only when the deviation angle between the steering angle and the turning angle is equal to or greater than θ1, the process proceeds to Step S13 to start SBW control. That is, when the deviation angle between the steering angle and the turning angle is equal to or larger than the predetermined value θ1, the torque acting in the engagement direction is sufficiently weakened, and the roller 32 in a state of being caught between the outer ring 30 and the inner ring 31 is used. (Engagement element) is released, and the clutch 5 is released reliably. By shifting to the SBW control from that point, the SBW control can be executed in a state where the clutch 5 is surely released, and the occurrence of handle removal can be prevented.

  Further, in step S7, the reaction force motor 4 applies a steering reaction force, and a process for increasing the steering torque by the applied steering reaction force is performed. In other words, by outputting the steering reaction force before the clutch release command when shifting from EPS control to SBW control, steering torque loss due to delay in the rise of reaction force output is prevented when shifting from EPS control to SBW control. be able to. Further, by increasing the steering torque, the steering reaction force generated by the reaction force motor 4 is canceled with the increased steering torque, and the fluctuation of the torque transmitted to the steering handle 1 is prevented. Variation can be suppressed.

  In step S9, a steering wheel turn-back determination is performed, and only in the case of switchback, the process proceeds from step S10 to step S11, and a clutch release command is output. That is, when the steering wheel 1 is turned back, the torque acting in the engagement direction is weakened. Therefore, the clutch 5 is reliably released by outputting the clutch release command at this time.

  On the other hand, in the case of rounding up at step S9, the process of step S1, step S5, step S6, step S7, step S8, step S9, step S2, step S3, step S4 is repeated, and the EPS control is continued. . When the steering handle 1 is further increased, the clutch 5 is in the engagement direction, so that the clutch 5 once released may be engaged again. In this case, by continuing the EPS control, it is possible to prevent the occurrence of steering wheel removal resulting from performing the SBW control when the clutch 5 is not released.

  If the steering wheel 1 is turned back while maintaining the EPS control and the deviation angle between the steering angle and the turning angle is equal to or greater than the predetermined value θ1, step S1, step S5, step S6, step S7, step S8 Step S9 → Step S10 → Step S11 → Step S12 → Step S13, and SBW control is started. In other words, when shifting to EPS control due to additional turning, if it is determined that it is possible to shift from EPS control to SBW control, SBW control is performed based on the deviation angle between the steering angle and the turning angle from the switching back steering point. Therefore, it is possible to quickly return to SBW control.

[Handle prevention action]
FIG. 7 shows a first embodiment in which the clutch 5 is engaged at the maximum turning angle to shift from the SBW control to the EPS control, and when the steering is returned, the clutch 5 is released and the EPS control is shifted to the SBW control again. This is a time chart showing the action of preventing the steering wheel from being taken off, and the operation in the situation where the steering angle is switched back after the turning angle reaches the maximum turning angle (rack end) by the driver's additional steering operation. Show.

  First, when the turning angle becomes Δf1 at time T0, a clutch engagement command is output, and the SBW control is shifted to EPS control. At the same time, the reaction force torque that has been output until then is turned off, and the turning torque becomes the turning assist torque by EPS control. When the driver turns back the steering angle, when the turning angle becomes less than δf2 at time T1, the reaction torque is output and the turning torque is increased by the reaction torque. Further, when the driver turns back the steering angle and the turning angle becomes less than Δf3 at time T2, the turning angle is held at Δf3, and a clutch release command is output.

  At this time, since the driver continues to perform the switchback steering, the deviation angle between the steering angle and the turning angle held at δf3 gradually increases, and the deviation angle becomes θ1 or more at time T3 (FIG. 8). Refer to), and shift to SBW control. As described above, the torque acting in the clutch engagement direction is weakened between the time points T2 and T3, and the clutch 5 is reliably released, so that the SBW control can be reliably shifted from the time point T3.

Next, the effect will be described.
In the vehicle steering apparatus according to the first embodiment, the following effects can be obtained.

  (1) When the clutch release command is output, the controller 10 controls the turning angle so that the turning angle change of the front wheels 9 becomes small with respect to the steering angle change. The occurrence of taking can be prevented.

  (2) The controller 10 holds the turning angle at the turning angle δf3 when the clutch release command is output. That is, since the turning angle is fixed and the torque acting only in the engaging direction is changed in the direction of weakening, the torque acting in the engaging direction can be weakened more quickly and engaged. The clutch 5 in the state is reliably released.

  (3) After the clutch release command is output, the controller 10 starts the SBW control when the deviation angle between the steering angle and the turning angle is equal to or greater than the predetermined value θ1, so the deviation angle between the steering angle and the turning angle is By being equal to or greater than the predetermined value θ1, the torque acting in the engagement direction is sufficiently weakened, and the engaged clutch 5 is reliably released. By shifting to the SBW control from that point, the SBW control can be performed in a state where the engagement of the clutch 5 is surely released, and the occurrence of handle removal can be prevented.

  (4) The controller 10 applies the steering reaction force by the reaction force motor 4 to the steering handle 1 before the clutch release command is output, and increases the steering torque of the steering mechanism 8 by the amount of the applied reaction force. When shifting from control to SBW control, it is possible to prevent the steering torque from being lost due to a delay in the rise of the reaction force motor output. In addition, when the reaction force torque is only output during EPS control, the reaction torque is added to the torque generated by the road surface external force, which increases the steering torque felt by the driver. By increasing the torque and increasing the assist of EPS control, the fluctuation of the steering torque felt by the driver can be suppressed.

  (5) If the steering wheel 1 is being turned back, a clutch release command is output (step S11). That is, at the time of turning back the steering wheel, the torque acting in the engaging direction is weakened. Therefore, the clutch 5 is reliably released by outputting the clutch release command at this time.

  (6) The controller 10 maintains the turning angle at the turning angle δf3 when the clutch release command is output, and maintains the EPS control when the steering handle 1 is steered further during the turning angle holding control. Further, it is possible to prevent the steering wheel from being removed by performing the SBW control in a state where the engagement of the clutch is not released.

  (7) When the EPS 10 is maintained by the driver's additional steering, the controller 10 is operated again when the steering wheel 1 is turned back, and the deviation angle between the steering angle and the turning angle becomes equal to or larger than the predetermined value θ1, the SBW Since control is started, it is possible to quickly return to SBW control.

  The second embodiment is an example in which the control shifts from the SBW control to the EPS control when overcoming the curbstone and returns to the SBW control again when the steering wheel is turned back. Since the system configuration is the same as that of the first embodiment, the description thereof is omitted.

  The controller 10 determines whether the curb has been climbed from the steering current of the steering motor 6, and when the curb has been climbed, the clutch 5 is engaged to shift from SBW control to EPS control. After that, when it is determined that the curbstone has been overcome from the steering current, the control shifts from EPS control to SBW control.

[Steering control processing]
FIG. 9 is a flowchart showing the flow of the steering control process executed by the controller 10 of the second embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  In step S21, it is determined whether or not the curbstone has been overcome by determining whether or not the absolute value of the steering current is equal to or greater than a predetermined value I1. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S5. Here, I1 is set to a relatively large value (for example, 70 A) at which the turning current does not exceed during normal traveling (when the vehicle is not over the curb).

  In step S22, it is determined whether or not the absolute value of the steering current is less than a predetermined value I2. If YES, the process proceeds to step S7. If NO, the process proceeds to return. Here, I2 is a value smaller than I1.

  In step S23, the command turning angle that is held at the angle at which the turning angle is determined to be switched back in step S9 is output, and the process proceeds to step S11.

Next, the operation will be described.
[Handle prevention action]

  FIG. 10 is a time chart showing the handle removal preventing effect of the embodiment 2 when the clutch 5 is engaged and the SBW control is shifted to the EPS control and the EPS control is shifted to the SBW control after the curb is climbed. There is shown an operation in a situation where the front wheel 9 hits the curb during the driver's additional steering, gets over the curb, and then switches back the steering angle.

  First, if the front wheel 9 hits the curb during the driver's steering operation, the change in the turning angle stops and the difference between the command turning angle and the actual turning angle becomes large. The current increases. When the steering current becomes equal to or greater than the predetermined value I1 at time T0, a clutch engagement command is output, and the process proceeds from SBW control to EPS control. By shifting from SBW control to EPS control, the driver's steering force can also be used as the steering force when getting over the curb.

  Overcoming the curb will reduce the steering current to normal control conditions. When the driver turns back the steering angle at time T2, the turning angle is held at the angle Δf1 at the time of turning back determination (step S23), and a clutch release command is output (step S11). At this time, if the driver increases the steering angle again at time T3 (see FIG. 11 (a)) before the deviation angle between the steering angle and the turning angle becomes equal to or greater than the predetermined value θ1, it acts in the clutch engagement direction. Since the torque to be applied is increased, the clutch may not be released by the clutch release command. Therefore, EPS control is performed again (step S9 → step S2).

  When the driver turns back the steering angle again at time T4, the turning angle is held at the angle δf2 at the time of turning back determination (step S23), and a clutch release command is output (step S11). Since the driver continues the switchback steering, the deviation angle between the steering angle and the turning angle held at δf2 increases, and when the deviation angle exceeds the predetermined value θ1 at time T5 (FIG. 11 (b)). Then, the process proceeds to SBW control (step S12 → step S13). As described above, the torque acting in the clutch engagement direction is weakened between the time points T4 and T5, and the clutch is released. Therefore, the SBW control can be reliably shifted from the time point T5.

  In the third embodiment, when the battery voltage as the power source of the steered motor decreases, the power consumption is reduced to prevent the battery voltage (hereinafter referred to as the power supply voltage) from decreasing. This is an example in which control is returned to SBW control again when the power supply voltage is sufficiently recovered after shifting to control. Since the system configuration is the same as that of the first embodiment, the description thereof is omitted.

  The controller 10 engages the clutch 5 when the power supply voltage drops and shifts from SBW control to EPS control. Thereafter, when it is determined that the power supply voltage has sufficiently recovered, the control shifts from EPS control to SBW control.

[Steering control processing]
FIG. 12 is a flowchart showing the flow of the steering control process executed by the controller 10 of the third embodiment, and each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  In step S31, it is determined whether or not the power supply voltage is equal to or lower than a predetermined value V1. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S5. Here, V1 is set to a value (for example, 10 V) with a margin corresponding to a threshold value that causes an abnormality in the system (capacity reduction due to insufficient voltage).

  In step S32, it is determined whether or not the power supply voltage is equal to or higher than a predetermined value V2. If YES, the process proceeds to step S33, and if NO, the process proceeds to return. Here, V2 is larger than V1.

  In step S33, it is determined whether or not the state where the power supply voltage is V2 or higher has elapsed for a predetermined time Tv or longer. If YES, the process proceeds to step S7. If NO, the process proceeds to return. Here, Tv is a value (for example, 5 minutes) at which it can be determined that the power supply voltage has sufficiently recovered.

Next, the operation will be described.
[Handle prevention action]
FIG. 8 is a time chart showing the handle removal preventing effect of the third embodiment when the SBW control is shifted to the EPS control when the power supply voltage is reduced, and the EPS control is shifted to the SBW control after the power supply voltage is recovered. The figure shows the operation in a situation where the driver turns and steers when the power supply voltage drops, and the steering angle is turned back after the power supply voltage recovers.

  First, when the power supply voltage decreases and becomes equal to or less than the predetermined value V1 at time T0, a clutch engagement command is output, and the SBW control is shifted to EPS control. By shifting from SBW control to EPS control, it is possible to reduce battery power consumption.

  When the power supply voltage recovers to the predetermined value V2 or more at the time point T1, and when the state further exceeds the predetermined time Tv, the state becomes possible to shift to SBW control. When the driver switches back the steering angle at time T3, the turning angle is held at the angle δf1 at the time of switching back (step S23), and a clutch release command is output (step S11). Since the driver continues the back-turn steering, the deviation angle between the steering angle and the turning angle held at δf1 increases, and when the deviation angle exceeds a predetermined value θ1 at time T4 (FIG. 14), SBW control is performed. (Step S12 → Step S13). As described above, the torque acting in the clutch engagement direction is weakened between the time points T3 and T4, and the clutch is released. Therefore, the normal SBW control can be surely shifted from the time point T4.

  In the fourth embodiment, when it is detected that the deviation angle between the steering angle and the steering angle is equal to or larger than a predetermined value (θ1) while the steering angle is maintained as in the first to third embodiments. Rather than determining that the clutch 5 has been released, the clutch 5 is released by driving the steering motor 6 so that the turning angle is smaller than the steering angle and actively making a turning operation. Different from Examples 1-3. Since the system configuration is the same as that of the first embodiment, the description thereof is omitted.

[Steering control processing]
FIG. 15 is a flowchart showing the flow of the steering control process executed by the controller 10 of the fourth embodiment, and each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  After outputting the clutch release command in step S11, in step S41, the value obtained by subtracting the steering angle θt (rotation angle of the pinion shaft 17) from the steering angle θfm (rotation angle of the pulley shaft 79) The command turning angle θta (θta = θfm−θ1) is calculated so as to be the predetermined angle θ1 necessary for canceling, and the process proceeds to step S23. The predetermined angle θ1 necessary for releasing the engaged state of the clutch 5 is a predetermined value as in the first embodiment.

  In step S42, the commanded steering angle is transmitted to the steering controller 11 so as to steer the front wheels 9 based on the commanded steering angle θta calculated in step S41, and the steering angle control is performed. Transition.

  In step S43, based on the turning angle detected by the turning angle sensor 7, whether or not the actual turning angle has changed to θta by the turning angle control performed in step S42 (the turning angle is θta). Whether or not). If it is determined that the change has occurred, the clutch release control ends, and the process proceeds to step S13. When it is determined that there is no change, the process proceeds to step S41, and the command turning angle θta is calculated again. The reason why θta is calculated again is that since the steering angle θs changes during steering, it is also necessary to change the command turning angle θta for releasing the clutch 5.

  In the fourth embodiment, as described above, the clutch 5 is released by driving the steering motor 6 so as to make the steering angle smaller than the steering angle and actively performing the steering operation. For this reason, the steering angle is maintained until it is detected that the deviation angle between the steering angle and the steering angle is equal to or greater than a predetermined value (θ1) in the state where the steering angle is maintained as in the first to third embodiments. Compared to the case of holding, the engagement of the clutch 5 can be reliably and quickly released. The process from step S11 to step S43 is referred to as clutch release control.

Next, the operation will be described.
[Handle taking prevention action]
Hereinafter, the steering gear ratio (steering angle / steering angle, i.e., the rotation angle of the pinion shaft 17 / the rotation angle of the pulley shaft 79) is less than 1 in the operation of preventing the steering wheel from being removed in the vehicle steering apparatus of the fourth embodiment. A description will be given separately for the case of being smaller and the case of being larger than 1.

(Steering gear ratio <1)
FIG. 16 shows a conventional vehicle steering apparatus in which the ratio of the command turning angle θta to the steering angle θs (hereinafter referred to as the steering gear ratio) Gr (= θta / θs) is smaller than 1 during the SBW control after the clutch release command. Each waveform in the case of control is shown.

  Conventionally, after the transition from SBW control to clutch engagement state at time t1 to EPS control as the clutch engagement state, when transitioning to SBW control at time t2, a clutch 5 release command has been issued, but a large torque in the engagement direction of the clutch 5 has been issued. When it is applied, the clutch 5 remains engaged. For this reason, since the pinion shaft 17 and the pulley shaft 79 remain connected, the steering handle 1 and the steering mechanism 8 are mechanically connected.

  Even if the driver tries to increase the rudder in this state, since the steering gear ratio of the SBW control is set to be smaller than 1, the command turning angle θta becomes smaller than the steering angle θs, and the steering motor 6 Steering torque is generated in a direction that suppresses the increase in turning. Therefore, the driver cannot steer the steering handle 1 unless the steering torque that overcomes the steering torque is input to the steering handle 1, and the steering handle 1 may be taken.

  On the other hand, in the fourth embodiment, as shown in FIG. 17, when the clutch engagement state is shifted to the SBW control at the time t2, the clutch release control is performed without immediately shifting to the SBW control (Step S11 → Step S41). → Step S42 → Step S43). In the clutch release control, a clutch release command is issued (step S11), and the steered motor 6 is driven in a direction in which the clutch engagement torque is reduced to relax the degree of engagement of the clutch 5 (step S42).

  Thereafter, it is determined whether or not the turning angle is θta at time t3 (step S43). If the turning angle is θta, the control shifts from the clutch release control to the SBW control (step S43). → Step S13). As a result, the clutch 5 can be reliably released, so that even when the driver increases the steering wheel 1 after the time point t3 when transitioning to the SBW control, the steering wheel is not removed.

(Steering gear ratio> 1)
FIG. 18 shows each waveform when the steering gear ratio Gr is controlled to be larger than 1 during the SBW control after the clutch release command in the conventional vehicle steering apparatus.

  Conventionally, after the SBW control is shifted from the SBW control to the EPS control with the clutch 5 in the engaged state at the time t10, when the transition to the SBW control is performed at the time t20, the release command of the clutch 5 has been issued but the clutch 5 is in the engagement direction. When a large torque is applied, the clutch 5 remains engaged. For this reason, since the pinion shaft 17 and the pulley shaft 79 remain connected, the steering handle 1 and the steering mechanism 8 are mechanically connected.

  Even if the driver tries to switch back the rudder in this state, the steering gear ratio of the SBW control is set to be larger than 1, so the change in the command turning angle θta is larger than the change in the steering angle θs. Thus, the steered motor 6 generates torque in the direction of turning back, and the front wheel 9 tries to move further. At this time, since the steering handle 1 and the steering mechanism 8 are still in a mechanically connected state, the steering handle 1 moves when the front wheels 9 are steered, thereby further increasing the command steering angle θta. There is a possibility that the steering wheel may be taken due to a cycle in which the front wheel 9 changes and is steered.

  On the other hand, in the fourth embodiment, as shown in FIG. 19, when shifting from the clutch engaged state to the SBW control at time t20, the clutch release control is performed without immediately shifting to the SBW control (step S11 → step S41 → step S42 → step S43). In the clutch release control, a clutch release command is issued (step S11), the steering motor 6 is driven in a direction in which the clutch engagement torque is reduced, and the degree of engagement of the clutch 5 is relaxed (step S42).

  Thereafter, it is determined whether or not the turning angle is θta at time t30 (step S43). If the turning angle is θta, the control shifts from clutch release control to SBW control (step S43). → Step S13). Thus, since the clutch 5 can be reliably released, even when the driver switches back the steering handle 1 after the time point t30 when the control shifts to the SBW control, the handle is not removed.

Next, the effect will be described.
In the vehicle steering apparatus of the fourth embodiment, the following effects can be obtained.

  (1) When the controller 10 shifts from the engaged state of the clutch 5 to the SBW control, the controller 10 outputs a clutch release command to the clutch 5, and the turning angle is a rotation deviation by a predetermined angle θa in the engagement release direction of the clutch 5. After performing clutch release control for driving the steered motor 6 to give an angle, SBW control is started. As a result, it is possible to suppress the removal of the handle that may occur when the SBW control is started with the clutch 5 engaged.

  (2) When the controller 10 shifts from the engaged state of the clutch 5 to the SBW control, the controller 10 outputs a clutch release command to the clutch 5, and the rotating shaft (pulley shaft 79) of the handle 1 and the rotating shaft of the steering mechanism 8. After performing the clutch release control for driving the steered motor 6 so as to apply the torque in the disengagement direction of the clutch 5 to the (pinion shaft 17), the SBW control is started. As a result, it is possible to suppress the removal of the handle that may occur when the SBW control is started with the clutch 5 engaged.

  In the fifth embodiment, in contrast to the fourth embodiment, clutch release control for releasing the clutch 5 is performed only when it is estimated that the clutch 5 is not engaged and released (not released) even if a clutch release command is output. The point is that clutch release control for releasing the clutch 5 is performed only when the influence of the clutch release control is small, and the method for determining that the clutch 5 is released is different. Since the system configuration is the same as that of the first embodiment, the description thereof is omitted.

[Steering control processing]
FIG. 20 is a flowchart showing the flow of the steering control process executed by the controller 10 of the fifth embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  In step S51, it is estimated whether or not the clutch 5 is disengaged when a clutch release command is output from the steering state or vehicle state. If it is estimated that the clutch 5 is disengaged, the process proceeds to step S55. If it is estimated that the clutch 5 is not disengaged, the process proceeds to step S52. Here, whether or not the clutch 5 is disengaged is determined by estimating the degree of engagement of the clutch 5. That is, the torque applied to the rotation direction of the clutch 5 that connects and releases the steering handle 1 and the steering mechanism 8 is the torque that is intended to rotate the steering handle 1 (torque applied to the pulley shaft 79) and the steering. Since the torque is intended to rotate the pinion shaft 17 of the mechanism 8, the torque (steering reaction force) detected by the torque sensor 3 and the axial force sensor 14 provided at the hub portion of the front wheel 9 are examples of the torque. The torque acting on the clutch 5 is estimated from the road surface reaction force detected in step 1, and the clutch engagement degree is obtained (corresponding to the engagement torque detecting means). Then, when the degree of clutch engagement is equal to or greater than a predetermined value (for example, 5 Nm or more) obtained in advance by experiments or the like, it is determined that the engagement is not disengaged. If it is determined that the clutch 5 is not disengaged, the process proceeds to step S52. If it is determined that the clutch 5 is disengaged, the process proceeds to step S55 to output a clutch release command, and the process proceeds to step S13 to perform SBW control. Do.

  That is, even if the clutch 5 is disengaged only by outputting a clutch release command, if the clutch release control for releasing the engagement of the clutch 5 by driving the steering motor 6 is performed, the clutch 5 While driving the steered motor 6 in the disengaged state, it is considered that there is a delay in the timing of shifting from EPS control to SBW control, and the clutch release timing and control switching timing do not match. Clutch release control is not performed. Here, in the fifth embodiment, as described in the fourth embodiment, clutch release control for releasing the engagement of the clutch 5 by driving the steering motor 6 so that the steering angle becomes smaller than the steering angle is performed. However, as described in the first to third embodiments, the steering angle may be maintained at δf3 and may be replaced with the control for releasing the engagement of the clutch 5.

  In step S52, it is determined whether or not the clutch release control can be executed. Here, it is estimated whether there is a possibility that the change in the vehicle behavior or the change in the steering reaction force generated by the clutch release control may become so large that the driver feels uncomfortable (vehicle behavior change amount estimation means, steering reaction force Change estimation means). If there is a possibility that a change in vehicle behavior or a change in steering reaction force may give the driver a sense of incongruity, it is determined that the clutch release control cannot be performed, and it is estimated that the change is small enough not to give the driver a sense of incongruity. Determines that the clutch release control can be executed.

That is, for example, the current yaw jerk is calculated based on the yaw rate detected by the yaw rate sensor 13 (see FIG. 1), and the clutch is released when the current yaw jerk is larger than a predetermined value (for example, larger than 20 ° / s ³ ). It is determined that the change in vehicle behavior due to the steering drive of the front wheels 9 accompanying the control is large and the driver is likely to feel uncomfortable, and it is determined that the clutch release control cannot be performed. On the other hand, if the current york jerk is less than the predetermined value (for example, 20 ° / s ³ or less), it is estimated that the change in vehicle behavior associated with the clutch release control is small, and it is difficult for the driver to feel discomfort. It is determined that control can be executed.

Alternatively, when the steering reaction force detected by the torque sensor 3 is larger than a predetermined value (for example, larger than 3 Nm), a response delay occurs in the reaction force motor 4 when the reaction force motor 4 is driven by SBW control. In this case, it is determined that there is a possibility that the steering reaction force loss becomes large and the driver may feel uncomfortable, and it is determined that the clutch release control cannot be executed. On the other hand, when the steering reaction force detected by the torque sensor 3 is a predetermined value or less (for example, 3 Nm or less), it is determined that there is a low possibility that the driver will feel uncomfortable even if the steering reaction force is lost. It is determined that the release control can be executed.
In this case, considering the response time of the reaction force motor 4, it may be determined that the clutch release control cannot be executed only when it is estimated that a large steering reaction force loss occurs.

  Or, when the driver is steering, it is easy for the driver to feel steering reaction force loss and vehicle behavior change, and it is difficult to feel the change during steering. For example, the steering speed is calculated from the steering angle detected by the steering angle sensor 2, and when the steering speed θsp is 10 ° / s or more, it is determined that the steering is being performed, and the clutch release control can be executed. On the other hand, when the steering speed θsp is less than 10 ° / s, it is determined that the steering is being held, and the clutch release control cannot be executed.

Note that the clutch release control may be performed when it is determined that the driver does not feel uncomfortable under all conditions such as the change in the vehicle behavior and the change in the steering reaction force. It does not matter. These conditions can be appropriately selected and combined.
If it is determined that the clutch release control can be executed, the process proceeds to step S53. If it is determined that the clutch release control cannot be performed, the process proceeds to step S2.

  In step S53, clutch release control is executed. The clutch release control in step S53 is the same as the control in step S11, step S41, step S42, and step S43 in FIG.

In step S54, it is determined whether or not the clutch 5 has been disengaged by the clutch release control. That is, when the clutch 5 is engaged, the clutch 5 is released by performing clutch release control, but the inner and outer rings 30 and 31 are engaged due to causes other than the biting of the roller 32. If there is a failure such that the electromagnet is not energized due to such sticking or disconnection, the steering handle 1 and the steering mechanism 8 cannot be physically separated, and the clutch release control is performed. Even if the clutch 5 is not released, the determination is made. This determination can be made based on state quantities such as a steering reaction force, a steering angle, and a turning angle that are changed by performing clutch release control. For example, it can be determined from the change direction of the steering reaction force with respect to the steering, the change direction of the steering angle, and the turning angle. The steering reaction force can be detected by the torque sensor 3, the steering angle can be detected by the steering angle sensor 2, and the turning angle can be detected by the turning angle sensor 7.
If it is determined that the clutch 5 is disengaged, the process proceeds to step S13 and SBW control is performed. If it is determined that the clutch 5 is not disengaged, the process proceeds to step S2 and EPS control is performed. Continue.

  In the fifth embodiment, at the time of shifting to SBW control, it is estimated whether or not the clutch 5 is disengaged (released) only by outputting the clutch disengagement command from the steering state or the vehicle state in step S51, and the disengagement is not performed. If it is estimated, the process proceeds to step S53 to perform clutch release control.

  That is, when the clutch engagement torque acting on the roller 32 of the clutch 5 is small, the clutch 5 is disengaged only by outputting a release command to the clutch 5. Therefore, it is estimated whether or not the clutch 5 is disengaged from the steering state and the vehicle state, and the clutch release control is performed only when the clutch 5 is not disengaged. As a result, it is possible to reliably match the timing of control switching to clutch release and SBW control.

  At this time, whether or not the clutch 5 is disengaged is determined by comparing the degree of clutch engagement estimated from the steering reaction force and the road surface reaction force with a predetermined value. That is, the torque applied to the rotation direction of the clutch 5 that connects or disconnects the steering handle 1 and the steering mechanism 8 is the torque that rotates the steering handle 1 (pulley shaft 79) and the pinion shaft 17. Torque. Therefore, by using the steering reaction force and the road surface reaction force that is input from the road surface, it is determined whether or not the clutch 5 is disengaged without directly observing the torque acting on the clutch 5 using a sensor or the like. It can be estimated.

  Further, in the SBW transition control, in step S52, whether or not the clutch release control can be executed is determined by the change in the vehicle behavior or the change in the steering reaction force accompanying the clutch release control (the degree of yaw jerk, steering speed reaction force loss, etc.). Accordingly, when it is determined that the clutch release control is executable, the process proceeds to the clutch release control in step S53, and a clutch release command is output.

  That is, when the clutch release control is executed, the front wheels 9 are steered, and it is estimated in advance whether there is a possibility that the change in the vehicle behavior due to the influence may become so great as to make the driver feel uncomfortable, When it is estimated that the change in the vehicle behavior is not so great as to give the driver a sense of incongruity, the clutch release control is executed, so that the actual vehicle behavior change is suppressed to a level that does not give the driver a sense of incongruity, and the clutch 5 is securely engaged. It becomes possible to cancel.

  In step S52, it is preliminarily estimated whether or not the steering reaction force loss that occurs when the clutch release control is executed instead of the condition due to the change in the vehicle behavior may become so great as to make the driver feel uncomfortable. However, when it is estimated that it is not so large that the driver feels uncomfortable, the process may proceed to the clutch release control in step S53.

  In other words, since the clutch release control is executed when the steering reaction force, which is a response that makes it easy for the driver to feel a change in behavior, is less than a predetermined amount of 3 Nm, the change in the steering reaction force due to the clutch release control can be reduced, and the uncomfortable feeling given to the driver is suppressed. It becomes possible.

  Furthermore, in step S52, it is replaced with the condition due to the change in the vehicle behavior, and it is determined whether or not the driver is steering based on whether or not the steering speed θsp is 10 ° / s or more. If it is determined, the process may proceed to clutch release control in step S53.

  In other words, since the front wheel 9 is moved in the clutch release control, when the clutch release control is executed in the steered state, the driver tends to feel fluctuations in vehicle behavior and steering reaction force. Therefore, by performing clutch release control only during steering, it is possible to suppress a sense of discomfort given to the driver.

  In step S52, when the change in vehicle behavior or the change in steering reaction force is small, the clutch release control in step S53 is executed in any case where the driver is steering. The present invention is not limited to this, and the process may proceed to the clutch release control in step S53 when a plurality of these conditions are satisfied.

  In the SBW shift control of the fifth embodiment, when it is determined in step S54 that the clutch 5 has not been released, the process proceeds to step S2 to output a clutch release command, and then shifts to EPS control.

  That is, the clutch 5 is not caused by the engagement between the inner and outer rings by the roller 32 but may not be released due to a failure that prevents the electromagnet from being energized due to sticking or disconnection. In the fifth embodiment, it is possible to determine whether or not the clutch 5 is released from state quantities such as a steering torque, a steering angle, and a turning angle that are changed by performing the clutch release control. Without shifting to EPS control, it is possible to suppress removal of the handle.

Next, the effect will be described.
In the vehicle steering system of the fifth embodiment, the following effects can be obtained in addition to the effects described in the fourth embodiment.

  (1) Since the controller 10 outputs the clutch release command only when it is estimated that the clutch 5 is not disengaged, it is possible to reliably match the timing of switching the clutch to the SBW control.

  (2) In order to estimate whether the clutch 5 is disengaged from the steering reaction force and the road surface reaction force, the controller 10 directly applies torque acting on the clutch 5 using a sensor or the like newly provided to the clutch 5. It is possible to estimate whether or not the clutch 5 is disengaged without observing.

  (3) The controller 10 executes the clutch release control when the york jerk, which is the vehicle behavior change amount accompanying the clutch release control, is equal to or less than a predetermined amount that does not give the driver a sense of incongruity. The clutch 5 can be reliably released without giving

  (4) The controller 10 executes the clutch release control when the steering reaction force loss that is the amount of change in the steering reaction force accompanying the clutch release control is equal to or less than a predetermined amount that is an allowable value that does not give the driver a sense of incongruity. The clutch 5 can be reliably released without giving the driver a sense of incongruity.

  (5) Since the controller 10 performs clutch release control when it is determined that the driver is steering, the clutch 5 can be reliably released without causing the driver to feel uncomfortable.

  (6) When the controller 10 determines that the clutch 5 has not been released after the clutch release control, the controller 10 shifts to EPS control. Therefore, the cause of the clutch 5 not being released is not the engagement of the clutch 5 but the energization of the electromagnet. Even in the case of a failure or the like, the handle can be prevented from being removed.

(Other examples)
As described above, the best mode for carrying out the present invention has been described based on each example. However, the specific configuration of the present invention is not limited to each example. 3, the two-way clutch shown in FIGS. 3 and 4 is shown as a clutch that engages the rotating shaft of the steering mechanism and the rotating shaft of the steering wheel with an engagement element. The structure of the clutch is arbitrary as long as it is a clutch that engages the shaft with an engagement element.

  In the first to fifth embodiments, the power steering control (EPS control) for driving the steered motor so as to add the auxiliary steering force to the driver's steering force from the steering wheel when the clutch is engaged is shown. For example, when the clutch is engaged, the steering mechanism may be driven only by the steering force of the driver.

  Further, in the fifth embodiment, an example in which the amount of change in the yaw jerk is estimated as the amount of change in vehicle behavior is shown. Any vehicle behavior that varies depending on the vehicle may be used.

1 is a configuration diagram of a steer-by-wire system to which a vehicle steering apparatus according to a first embodiment is applied. It is a turning angle control system block diagram of Example 1. FIG. It is sectional drawing which shows the clutch in the steering apparatus for vehicles of Example 1. FIG. It is a figure which shows the mechanical clutch part of the clutch in the steering apparatus for vehicles of Example 1. FIG. 4 is a flowchart illustrating a flow of a steering control process executed by the controller 10 according to the first embodiment. It is a time chart which shows the problem of a prior art. 3 is a time chart illustrating a handle removal preventing effect of the first embodiment. FIG. 8 is an enlarged view of part A (SBW transition timing) in FIG. 7. 7 is a flowchart illustrating a flow of a steering control process executed by a controller 10 according to a second embodiment. 6 is a time chart illustrating a handle removal preventing effect of the second embodiment. FIG. 11 is an enlarged view of a B portion (timing not to shift to SBW) and a C portion (timing to shift to SBW) in FIG. 10. 10 is a flowchart illustrating a flow of steering control processing executed by a controller 10 according to a third embodiment. 10 is a time chart showing an action of preventing a handle from being taken in Example 3. It is the D section (SBW shift timing) enlarged view of FIG. 10 is a flowchart illustrating a flow of a steering control process executed by a controller 10 according to a fourth embodiment. 6 is a time chart showing waveforms when a ratio of a steering command angle to a steering angle (steering gear ratio) is controlled to be smaller than 1 in SBW control after a clutch release command in a conventional vehicle steering apparatus. In Example 4, it is a time chart which shows each waveform in the case of controlling by making ratio (steering gear ratio) of the steering command angle with respect to a steering angle smaller than 1 by SBW control after a clutch release command. 6 is a time chart showing waveforms when a ratio of a steering command angle to a steering angle (steering gear ratio) is controlled to be larger than 1 in SBW control after a clutch release command in a conventional vehicle steering apparatus. In Example 4, it is a time chart which shows each waveform in the case of controlling by making ratio (steering gear ratio) of a steering command angle with respect to a steering angle larger than 1 by SBW control after a clutch release command. 10 is a flowchart illustrating a flow of steering control processing executed by a controller 10 according to a fifth embodiment.

Explanation of symbols

1 Steering handle 2 Steering angle sensor (steering angle detection means)
3 Torque sensor 4 Reaction force motor (steering reaction force motor)
5 Clutch 6 Steering motor (steering actuator)
7 Steering angle sensor (steering angle detection means)
8 Steering mechanism 9 Front wheel (steering wheel)
10 Controller (steering control means)
11 Steering controller 12 Communication line 13 Yaw rate sensor 14 Axial force sensor 17 Pinion shaft (steering rotation axis)
21 Model matching compensator 22 Robust compensator 30 Outer ring 31 Inner ring 32 Roller (engagement element)
33 Clutch case 34 End plate 35 Electromagnetic coil 36 Permanent magnet 37 Rotor 38 Separating spring 39 Armature 40 Cage 41 Neutral spring 42 Needle bearing 43 Ball bearing 44 Ball bearing 45 Ball bearing 79 Pulley shaft (handle rotating shaft)

Claims (12)

A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
With
When the steering control means releases the engagement of the clutch from the engaged state and shifts to the steer-by-wire control, the steering rotation shaft responds to a rotation angle change of the handle rotation shaft. Clutch release control is performed so that the turning mechanism is driven so that a change in the rotation angle of the clutch is reduced, and a rotation deviation angle in the disengagement direction of the clutch is provided between the turning shaft and the steering shaft. A vehicle steering apparatus characterized by the above. The vehicle steering apparatus according to claim 1,
When the steering control means releases the engagement of the clutch from the engaged state and shifts to the steer-by-wire control, the steering control unit determines the rotation angle of the turning shaft so that the clutch is engaged. By releasing the engagement of the clutch from the state and maintaining the rotation angle when shifting to the steer-by-wire control, the rotation angle change of the steering rotation shaft is changed with respect to the rotation angle change of the steering wheel rotation shaft. A vehicle steering apparatus characterized by being made small. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
A steering actuator for applying torque to the steering rotation shaft;
With
The steering control means controls the steering actuator to release the clutch from the engaged state and shift to the steer-by-wire control to control the steering rotation shaft and the steering wheel. A vehicle steering apparatus that performs clutch release control that gives a rotation deviation angle in a direction of releasing the clutch between the rotary shaft and the rotary shaft. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
Engagement torque detecting means for detecting the engagement torque of the clutch;
With
When the steering control unit releases the clutch from the engaged state and shifts to the steer-by-wire control, the engagement torque detected by the engagement torque detecting unit is a predetermined value. In the above-described case, the vehicle steering apparatus is configured to perform clutch release control that gives a rotation deviation angle in the engagement release direction of the clutch between the steering rotation shaft and the handle rotation shaft. The vehicle steering device according to claim 4 ,
The vehicle steering apparatus according to claim 1, wherein the engagement torque detecting means estimates an engagement torque of the clutch from a steering reaction force and a road surface reaction force. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
With
When the steering control means releases the clutch engagement from the engaged state and shifts to the steer-by-wire control, the steering control unit includes the steering rotation shaft between the steering rotation shaft and the steering wheel rotation shaft. Perform clutch release control that gives the rotation deviation angle in the clutch release direction,
Vehicle behavior change amount estimation means for estimating a vehicle behavior change amount associated with the clutch release control is provided;
The vehicle steering apparatus according to claim 1, wherein the steering control unit executes the clutch release control when the vehicle behavior change amount estimated by the vehicle behavior change amount estimation unit is equal to or less than a predetermined amount. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
A steering reaction force change amount estimating means for estimating a change amount of the steering reaction force;
With
When the steering control unit releases the clutch from the engaged state and shifts to the steer-by-wire control, the steering control unit estimates the steering reaction force estimated by the steering reaction force change amount estimating unit. When the amount of change is less than or equal to a predetermined amount, the vehicle steering is characterized in that clutch release control is performed to provide a rotation deviation angle in the clutch disengagement direction between the turning shaft and the steering wheel shaft. apparatus. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
Steering detection means for detecting whether or not the driver is steering;
With
The steering control means detects that the driver is steering by the steering detection means when the clutch is released from the engaged state to shift to the steer-by-wire control. In this case, the vehicle steering apparatus is configured to perform clutch release control that provides a rotation deviation angle in the engagement release direction of the clutch between the steering rotation shaft and the steering wheel rotation shaft. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
A turning angle detecting means for detecting a turning angle that is a rotation angle of the turning shaft;
Steering angle detection means for detecting a steering angle which is a rotation angle of the steering wheel rotation shaft;
With
When the steering control means releases the clutch engagement from the engaged state and shifts to the steer-by-wire control, the steering control unit includes the steering rotation shaft between the steering rotation shaft and the steering wheel rotation shaft. Clutch release control for giving a rotation deviation angle in the clutch disengagement direction is performed, and after the clutch release control is started, the steering angle detected by the steering angle detection means and the turning angle detected by the turning angle detection means When the deviation angle with respect to the vehicle is greater than or equal to a predetermined value, the steer-by-wire control is started. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
A steering reaction force motor that applies a steering reaction force to the handle during the steer-by-wire control;
With
The steering control means applies a steering reaction force to the steering wheel and releases the applied steering reaction when the clutch is released from the engaged state to shift to the steer-by-wire control. After increasing the torque to be applied to the steered mechanism by the force, clutch release control is performed between the steered rotating shaft and the handle rotating shaft to give a rotation deviation angle in the clutch disengagement direction. A vehicle steering apparatus characterized by the above. A steering wheel steerable by the driver;
A steering mechanism connected to the steering wheel;
An engaging member that is engageable between a turning shaft that is connected to the turning mechanism and rotates in accordance with a turning operation of the turning mechanism and a handle turning shaft that is a turning shaft of the handle; The steering mechanism and the steering wheel are mechanically coupled by fastening with an engaging member between the steering rotating shaft and the steering wheel rotating shaft, and the steering rotating shaft and the steering wheel rotating shaft A clutch capable of releasing the engagement by releasing the engagement of the engaging element engaged between the steering mechanism and the mechanical connection between the steering mechanism and the handle;
Steering control means for performing steer-by-wire control for driving the steered wheels by driving the steered mechanism according to the steering state of the steering wheel in a state where the clutch is released.
With
When the steering is being steered in the reversing direction when the clutch is released from the engaged state and the steering control is shifted to the steer-by-wire control, A vehicle steering apparatus that performs clutch release control that gives a rotation deviation angle in a direction in which the clutch is disengaged between a rudder rotation shaft and the steering wheel rotation shaft. The vehicle steering apparatus according to claim 11 , wherein
When the steering is being steered in an increasing direction when the clutch is released from the engaged state and the steering control is shifted to the steer-by-wire control, A vehicular steering apparatus that holds a clutch engaged.

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