Steering control device

Abstract

To provide a steering control device that can determine whether steering intervention is present or absent.SOLUTION: A PU 52 executes, at startup, processing to align a steering angle with a steered angle by operating a reaction force motor 22 when the steering angle and the steered angle do not match. In the processing, the PU 52 controls torque of the reaction force motor 22 by an operation amount of control in which the steering angle is a control amount and a target steering angle is a target value of the control amount. The PU 52 determines that there is steering intervention by a driver when a deviation between the steering angle and the target steering angle is large.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a steering control device.

Background Art

[0002] Patent Document 1 below describes a steer-by-wire system that is a system in which power transmission between a steering wheel and a steering shaft is interrupted. When the steering angle and the steering angle do not match when the vehicle power is turned on, the control device described in the same document rotates the steering shaft so as to match.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If the driver touches the steering wheel during execution of the process of matching the steering angle and the steering angle as described above, there is a risk that the control cannot be completed. Therefore, it has been considered to issue a notification prompting the driver to pay attention when the magnitude of the steering torque is equal to or greater than a predetermined value during execution of the control. However, in that case, if there is an abnormality in the sensor that detects the steering torque, the process of issuing the notification cannot be executed.

Means for Solving the Problems

[0005] Hereinafter, means for solving the above problems and their effects will be described. 1. In a steering control device that operates a reaction force motor that applies a reaction force to a steering shaft, in a state where power transmission between the steering shaft and the steered wheels is interrupted, displacement processing and intervention determination processing are executed. The displacement processing is a process of operating the reaction force motor to rotate the steering shaft by a predetermined amount on the premise that the driver does not perform a rotation operation of the steering shaft. The intervention determination processing is a process of determining that there is a steering intervention that obstructs the displacement processing by the driver based on the value of a steering angle variable as an input variable. The steering angle variable is a variable indicating the displacement of the steering shaft based on the detection value of a sensor.

[0006] The behavior of the steering shaft due to the displacement processing becomes specific to the displacement processing. Therefore, when the behavior of the steering shaft deviates from what is assumed from the displacement processing, it can be determined that there is a steering intervention by the driver. Therefore, with the above configuration, it is possible to determine the presence or absence of steering intervention based on the value of the steering angle variable.

[0007] 2. The displacement processing includes a process of operating the reaction force motor by an operation amount of control in which the steering angle is a control amount and the target steering angle is a target value of the control amount. The steering angle is the rotation angle of the steering shaft. The intervention determination processing includes a process of determining that there is a steering intervention when the degree of deviation between the steering angle and the target steering angle is equal to or greater than a predetermined value. The steering control device according to 1 above.

[0008] If, despite the displacement processing being performed, the degree of deviation between the steering angle and the target steering angle is large, it is considered that there is a steering intervention that obstructs the displacement processing by the driver. Therefore, with the above configuration, it is possible to determine the presence or absence of steering intervention by paying attention to the degree of deviation between the steering angle and the target steering angle.

[0009] 3. The displacement process includes a process of displacing the steering angle at the target steering angular velocity. The steering angle is the rotation angle of the steering shaft. The intervention determination process includes a process of determining that there is steering intervention when the degree of deviation between the steering angular velocity and the target steering angular velocity is equal to or greater than a predetermined value. The steering control device according to 1 or 2 above.

[0010] Even if the displacement process is being performed, if the degree of deviation between the steering angular velocity and the target steering angular velocity is large, it is considered that there is steering intervention that hinders the displacement process by the driver. Therefore, in the above configuration, the presence or absence of steering intervention can be determined by paying attention to the degree of deviation between the steering angular velocity and the target steering angular velocity.

[0011] 4. The intervention determination process includes a process of determining that there is steering intervention when the execution time of the displacement process exceeds the required time for completion of the displacement process by a predetermined amount or more. The steering control device according to any one of 1 to 3 above.

[0012] The time until the displacement process is completed can be grasped in advance. Therefore, in the above configuration, the presence or absence of steering intervention can be determined by paying attention to the degree to which the execution time of the displacement process exceeds the required time for completion of the displacement process.

[0013] 5. It is configured to execute a warning process. The displacement process includes an alignment process of rotating the steering shaft to align the steering angle and the steering angle of the steered wheels when they are not aligned. The steering angle is the rotation angle of the steering shaft. The warning process includes a process of warning that the alignment process is being executed when it is determined that there is steering intervention during the execution of the alignment process. The steering control device according to any one of 1 to 4 above.

[0014] In the above configuration, when the driver performs steering intervention during the execution of the alignment process, by warning the driver, the driver can be made to stop performing steering intervention. 6. The steering control device according to the above 5, wherein the alignment process is configured to be executed on the condition that the steering angle and the steering angle are not aligned when the vehicle start switch is switched from the off state to the on state.

[0015] In the above configuration, after the start switch is switched to the on state, the steering angle and the steering angle can be quickly aligned by the alignment process. 7. The steering control device according to any one of the above 1 to 6, which is configured to execute an end fitting process, an end determination process, a maximum displacement variable acquisition process, a midpoint learning process, and a caution process, wherein the end fitting process is a process of displacing the steering shaft to the maximum extent on at least one of the right turn side and the left turn side by operating the reaction motor, the end determination process is a process of determining whether or not the steering shaft has been displaced to the maximum extent, the maximum displacement variable acquisition process is a process of acquiring the value of the maximum displacement variable, the maximum displacement variable is a variable obtained based on the determination that the maximum displacement has been determined by the end determination process, the midpoint learning process is a process of learning the midpoint of the rotation angle of the steering shaft based on the value of the maximum displacement variable as an input variable, the displacement process includes the end fitting process, and the caution process includes a process of cautioning that the end fitting process is being executed when it is determined that there is steering intervention during the execution of the end fitting process.

[0016] In the above configuration, when the driver intervenes in steering during the execution of the end fitting process for midpoint learning, the driver can be made to stop intervening in steering by cautioning the driver.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0018] Hereinafter, an embodiment will be described with reference to the drawings. 「Premise Configuration」 The vehicle steering device 10 shown in FIG. 1 is a steer-by-wire type device. The steering device 10 includes a steering wheel 12, a steering shaft 14, a reaction force actuator 20, and a steering actuator 30. The steering shaft 14 is connected to the steering wheel 12. The reaction force actuator 20 applies a force that resists the force with which the driver operates the steering wheel 12. The reaction force actuator 20 has a reaction force motor 22, a reaction force inverter 24, and a reaction force reduction mechanism 26. The reaction force motor 22 applies a steering reaction force, which is a force that resists steering, to the steering wheel 12 via the steering shaft 14. The reaction force motor 22 is connected to the steering shaft 14 via the reaction force reduction mechanism 26. The reaction force motor 22 is, for example, a three-phase surface magnet synchronous motor. The reaction force reduction mechanism 26 is composed of, for example, a worm and a wheel.

[0019] The steering actuator 30 steers the steered wheels 34 according to the driver's steering intention indicated by the operation of the steering wheel 12 by the driver. The steering actuator 30 includes a rack shaft 32, a steering motor 42, a steering inverter 44, a steering transmission mechanism 46, and a conversion mechanism 48. The steering motor 42 is, for example, a three-phase synchronous motor. The steering transmission mechanism 46 consists of a belt transmission mechanism. The rotational power of the steering motor 42 is transmitted to the conversion mechanism 48 by the steering transmission mechanism 46. The conversion mechanism 48 converts the transmitted rotational power into the displacement power in the axial direction of the rack shaft 32. The steered wheels 34 are steered by the displacement of the rack shaft 32 in the axial direction.

[0020] The reaction force control device 50 includes a PU 52 and a storage device 54. The PU 52 is a software processing device such as a CPU and a GPU. The storage device 54 may be a non-volatile memory that is electrically non-rewritable. The storage device 54 may also be a non-volatile memory that is electrically rewritable and a storage medium such as a disk medium.

[0021] The control target of the reaction force control device 50 is the steering wheel 12. The reaction force control device 50 controls the steering reaction force against the driver's steering, which is the control amount of the steering wheel 12.

[0022] The reaction force control device 50 refers to the steering torque Th detected by the torque sensor 56 for the control of the control amount. The steering torque Th is the torque applied to the steering shaft 14 by the driver through the operation of the steering wheel 12. The reaction force control device 50 refers to the rotation angle θa, which is the angle of the rotation axis of the reaction force motor 22, detected by the steering-side rotation angle sensor 58 for the control of the control amount. Further, the reaction force control device 50 refers to the currents ius, ivs, iws flowing through the reaction force motor 22 for the control of the control amount. The currents ius, ivs, iws may be detected, for example, as the voltage drop amounts of shunt resistors provided in each leg of the reaction force inverter 24.

[0023] The steering control device 60 includes a PU 62 and a storage device 64. The PU 62 is a software processing device such as a CPU and a GPU. The storage device 64 may be a non-volatile memory that is electrically non-rewritable. The storage device 64 may also be an electrically rewritable non-volatile memory and a storage medium such as a disk medium.

[0024] The control target of the steering control device 60 is the steering wheel 34. The steering control device 60 controls the steering angle, which is the control amount of the steering wheel 34. The steering angle is the slip angle of the tire as the steering wheel 34.

[0025] For controlling the control amount, the steering control device 60 refers to the rotation angle θb, which is the angle of the rotation axis of the steering motor 42, detected by the steering side rotation angle sensor 66. Also, for controlling the control amount, the steering control device 60 refers to the currents iut, ivt, iwt flowing through the steering motor 42. The currents iut, ivt, iwt may be detected, for example, as the voltage drop amounts of shunt resistors provided in each leg of the steering inverter 44.

[0026] "Configuration of the reaction force actuator 20" FIG. 2 shows a partial configuration of the reaction force actuator 20. As shown in FIG. 2, the reaction force actuator 20 includes a housing 70 fixed to the vehicle. The steering shaft 14 is inserted into the housing 70. The housing 70 rotatably supports the steering shaft 14. The steering shaft 14 is inserted into a plurality of ring-shaped members. The ring-shaped members include washers 80, an intermediate stopper 90, washers 82, an end stopper 100, wave washers 84, and a C-shaped retaining ring 86.

[0027] The housing 70 is provided with a protrusion 72 as a regulating member for regulating the rotation of the intermediate stopper 90. The intermediate stopper 90 is provided with a protrusion 92 whose rotation is restricted by the protrusion 72.

[0028] Figure 3 shows a partial cross-sectional configuration of the reaction force actuator 20. As shown in Figure 3, an elastic force in the rightward direction in the figure is exerted on the end stopper 100 by the wave washer 84. As a result, an elastic force is exerted on the intermediate stopper 90 in the rightward direction via the washer 82. On the other hand, the steering shaft 14 has a reduced-diameter portion at the left end in the figure. The washer 80, the intermediate stopper 90, and the washer 82 are arranged at the reduced-diameter portion of the steering shaft 14. Therefore, the displacement of the washer 80 to the right in the figure is restricted. Therefore, an elastic force that causes the intermediate stopper 90 to move to the right in the figure is exerted by the washer 82, and an elastic force that causes the intermediate stopper 90 to move to the left in the figure is exerted by the washer 80.

[0029] The end stopper 100 is fixed to the steering shaft 14. Therefore, as the steering shaft 14 rotates, the end stopper 100 rotates integrally with the steering shaft 14. As the end stopper 100 rotates, the intermediate stopper 90 is rotated along.

[0030] "Restriction of rotation of the steering shaft 14" Figure 4 shows the operation of the intermediate stopper 90 as the steering shaft 14 rotates. The upper part of Figure 4 shows the case where the steering shaft 14 rotates to the right-turn side. The left end of the upper part of Figure 4 shows a state where the steering angle θh, which is the rotation angle of the steering shaft 14, corresponds to the value at the left-turn side end. And in the upper part of Figure 4, as it moves to the right in the figure, it shows a state where the steering shaft 14 rotates to the right-turn side. In particular, the right end of the upper part of Figure 4 shows a state where the steering angle θh corresponds to the value at the right-turn side end.

[0031] As shown in the upper part of FIG. 4, when the steering shaft 14 rotates clockwise from the counterclockwise end, the intermediate stopper 90 is rotated along with the rotation of the end stopper 100. In the center of the upper part of FIG. 4, a state is shown where the protrusion 92 of the intermediate stopper 90 contacts the protrusion 72 of the housing 70. As a result, the intermediate stopper 90 cannot rotate clockwise any further. Therefore, the end stopper 100 rotates independently as the steering shaft 14 rotates. Then, as the steering shaft 14 rotates further, when the protrusion 102 of the end stopper 100 contacts the protrusion 92 of the intermediate stopper 90, the end stopper 100 cannot rotate clockwise any further. This state is shown at the right end of the upper part of FIG. 4. In this state, the steering shaft 14 cannot rotate further to the right. The steering angle θh at this time becomes the upper limit value on the clockwise side.

[0032] The lower part of FIG. 4 shows the case where the rotation angle of the steering shaft 14 rotates counterclockwise. The left end of the lower part of FIG. 4 shows a state where the steering angle θh is a value corresponding to the clockwise end. And in the lower part of FIG. 4, as it moves to the right in the figure, a state where the steering shaft 14 rotates counterclockwise is shown. In particular, the right end of the lower part of FIG. 4 shows a state where the steering angle θh is a value corresponding to the counterclockwise end.

[0033] As shown in the lower part of FIG. 4, when the steering shaft 14 rotates counterclockwise from the right-rotating end, the intermediate stopper 90 is rotated along with the rotation of the end stopper 100. In the center of the lower part of FIG. 4, a state is shown in which the protrusion 92 of the intermediate stopper 90 contacts the protrusion 72 of the housing 70. As a result, the intermediate stopper 90 cannot rotate counterclockwise any further. Therefore, the end stopper 100 rotates independently as the steering shaft 14 rotates. Then, when the steering shaft 14 rotates further and the protrusion 102 of the end stopper 100 contacts the protrusion 92 of the intermediate stopper 90, the end stopper 100 cannot rotate counterclockwise any further. This state is shown at the right end of the lower part of FIG. 4. In this state, the steering shaft 14 cannot rotate further to the left. The steering angle θh at this time becomes the upper limit value on the counterclockwise rotation side.

[0034] "Processing at Startup" FIG. 5 shows the procedure of the processing at startup of the reaction force control device 50. The processing shown in FIG. 5 is realized by the PU 52 executing the program stored in the storage device 54 triggered by the startup of the reaction force control device 50. Hereinafter, the step numbers of each process are represented by numbers with "S" added at the beginning.

[0035] In the series of processes shown in FIG. 5, the PU 52 first determines whether or not the steering-side N-point learning data 54a is stored (S10). As shown in FIG. 1, the storage device 54 of the reaction force control device 50 normally stores steering side N-point learning data 54a indicating N-point learning values that are learning values of the steering angle θh during straight travel. On the other hand, the storage device 64 of the steering control device 60 stores steering side N-point learning data 64a indicating N-point learning values that are learning values of the steering angle during straight travel. The steering side N-point learning data 64a is stored in the storage device 64, for example, before the steering device 10 is shipped. On the other hand, in the present embodiment, the reaction force control device 50 executes a process of acquiring N-point learning values at the first startup of the reaction force control device 50 after shipment. Further, the reaction force control device 50 executes a process of acquiring N-point learning values even when, for example, the steering control device 60 is started immediately after the steering side N-point learning data 54a has disappeared from the storage device 54 due to battery replacement or the like. The conditions for the reaction force control device 50 and the steering control device 60 to start communication for vehicle steering include the condition that each holds N-point learning values.

[0036] Returning to FIG. 5, when the PU 52 determines that the steering side N-point learning data 54a is not stored (S10: NO), it sets the control mode to the N-point learning mode and executes the N-point learning process (S12).

[0037] On the other hand, when the PU 52 determines that the steering side N-point learning data 54a is stored (S10: YES) and when the N-point learning mode has ended, it determines whether the steering angle θh and the equivalent steering angle θp match (S14). The equivalent steering angle θp is a variable indicating the steering angle of the steered wheels 34. The PU 72 calculates a target equivalent steering angle θp* based on the vehicle speed V and the steering angle θh as input variables. When the deviation between the target equivalent steering angle θp* and the equivalent steering angle θp is less than a predetermined value, the PU 52 determines that the steering angle θh and the equivalent steering angle θp match. When the PU 52 determines that the steering angle θh and the equivalent steering angle θp do not match (S14: NO), it shifts to the synchronization control mode and executes the synchronization control process (S16). Note that the steering angle θh is calculated by the PU 52 based on the rotation angle θa as an input variable. Further, the equivalent steering angle θp is calculated by the PU 72 based on the rotation angle θb as an input variable.

[0038] When the PU52 determines that the steering angle θh and the equivalent steering angle θp are matched (S14: YES), or when the synchronization control is completed, the control mode is set to the normal control mode (S18). The normal control mode is a mode for executing processes related to the steering of the vehicle in cooperation with the steering control device 60.

[0039] When the PU52 completes the process of S18, the series of processes shown in FIG. 5 is temporarily terminated. "N-point learning mode" The process of the reaction force control device 50 acquiring the N-point learning value is performed by displacing the steering angle θh to the upper limit value on the right turn side. Hereinafter, this will be described.

[0040] FIG. 6 shows the detailed procedure of the process of S12. The series of processes shown in FIG. 6 is realized by the PU52 repeatedly executing the program stored in the storage device 54, for example, at a predetermined cycle.

[0041] In the series of processes shown in FIG. 6, the PU52 first determines whether the operation mode in the N-point learning mode is the right turn mode (S22). The operation mode is set to the right turn mode when the control mode switches to the N-point learning mode. When the PU52 determines that it is the right turn mode (S22: YES), the value obtained by adding a predetermined amount Δ to the target steering angle θh* is substituted into the target steering angle θh* (S24). Then, the PU72 determines whether the logical product of the following conditions (A) to (C) has been true for a certain period of time (S26).

[0042] Condition (A) is a condition that the absolute value of the steering torque Th is equal to or less than a predetermined value. This condition means that the driver is not operating the steering wheel 12. Condition (B) is a condition that the previous value "θh(n - 1)" and the current value "θh(n)" of the steering angle θh are the same.

[0043] Condition (C) is a condition that the absolute value of the q-axis current iqs flowing through the reaction force motor 22 is equal to or greater than the threshold value Ith. The threshold value Ith is set to a value larger than the value assumed as the absolute value of the q-axis current iqs when displacing the steering angle θh when the steering angle is in the intermediate region between the upper limit value on the right turn side and the upper limit value on the left turn side. For example, when the feedback control in the process of S34 described later includes a proportional term, the threshold value Ith may be equal to or greater than the output value of the proportional term when the absolute value of the difference between the target steering angle θh* and the steering angle θh becomes a predetermined amount Δ. Further, when the feedback control in the process of S34 includes an integral term, the threshold value Ith may be a value for determining that the integral windup phenomenon is occurring. Note that the q-axis current iqs is calculated by the PU52 based on the rotation angle θa and the currents ius, ivs, iws as input variables.

[0044] The fact that the above logical product is true is a condition for determining that the steering angle has reached the upper limit value on the right turn side. That is, if Condition (A) is satisfied, it is understood that the driver is not prevented from rotating the reaction force motor 22 to rotate the steering shaft 14. Therefore, when reaching the upper limit value on the right turn side when Condition (A) is satisfied, Condition (B) is satisfied. Further, when reaching the upper limit value on the right turn side, since the absolute value of the difference between the target steering angle θh* and the steering angle θh cannot be reduced, the absolute value of the torque of the reaction force motor 22 increases and Condition (C) is satisfied.

[0045] When the PU52 determines that the state in which the logical product of Conditions (A) to (C) is true has continued for a certain period of time (S26: YES), the current value "θh(n)" of the steering angle θh is substituted into the target steering angle θh* (S28). Then, the current value "θh(n)" is substituted into the right upper limit value θhR (S30).

[0046] PU72 switches the operation mode to the midpoint movement mode (S32). When PU52 completes the process of S32 and when a negative determination is made in the process of S26, PU52 calculates a target torque Ts* according to the operation amount by feedback control in which the steering angle θh is a control amount and the target steering angle θh* is a target value of the control amount (S34). The target torque Ts* is the target value of the torque of the reaction force motor 22.

[0047] Then, PU52 outputs an operation signal MSs of the reaction force inverter 24 to the reaction force inverter 24 in order to make the torque of the reaction force motor 22 approach the target torque Ts* (S36). On the other hand, when a negative determination is made in the process of S22, PU52 substitutes, into the left upper limit value θhL, a value obtained by subtracting the mechanical end interval θLR from the right upper limit value θhR (S38). The mechanical end interval θLR indicates the magnitude of the displaceable angular range of the steering angle θh. This angular range is the change range of the steering angle θh from the state shown at the left end to the state shown at the right end in the upper part of FIG. 4. PU52 acquires the mechanical end interval θLR by reading the mechanical end interval data 54b stored in the storage device 54.

[0048] PU52 substitutes "1 / 2" of the sum of the right upper limit value θhR and the left upper limit value θhL into the midpoint θhmd (S40). Then, PU52 determines whether the steering angle θh coincides with the midpoint θhmd (S42). When PU72 determines that the steering angle θh does not coincide with the midpoint θhmd (S42: NO), after substituting a value obtained by subtracting a predetermined amount Δ from the target steering angle θh* into the target steering angle θh* (S44), the process proceeds to S34.

[0049] On the other hand, when PU72 determines that the steering angle θh coincides with the midpoint θhmd (S42: YES), PU72 ends the N-point learning mode (S46). Note that when PU72 completes the processes of S36 and S46, PU72 temporarily ends the series of processes shown in FIG. 6.

[0050] "Synchronization control mode" Fig. 7 shows the detailed procedure of the process of S16. In the series of processes shown in Fig. 7, the PU52 first obtains the equivalent steering angle θp (S50). Next, the PU52 calculates the corresponding steering angle θh*0, which is the steering angle θh that matches the equivalent steering angle θp (S52). The corresponding steering angle θh*0 is the steering angle θh when the vehicle speed V is zero and the PU72 calculates the target equivalent steering angle θp* to be equal to the equivalent steering angle θp.

[0051] Also, the PU52 obtains the steering angle θh (S54). Then, the PU52 determines whether the corresponding steering angle θh*0 is equal to the steering angle θh (S56). When the PU52 determines that the corresponding steering angle θh*0 is not equal to the steering angle θh (S56: NO), it determines whether it is the time point when the synchronous control mode is switched (S58). When the PU52 determines that it is the switched time point (S58: YES), it substitutes the steering angle θh into the target steering angle θh* (S60).

[0052] When the PU52 completes the process of S60 and when it makes a negative determination in the process of S58, the PU52 updates the target steering angle θh* so as to reduce the difference between the target steering angle θh* and the corresponding steering angle θh*0 by a predetermined amount Δ (S62). Then, the PU52 substitutes the operation amount of the feedback control, where the steering angle θh is the control amount and the target steering angle θh* is the target value of the control amount, into the target torque Ts* (S64). The target torque Ts* is the target value of the torque of the reaction motor 22. Then, an operation signal MSs of the reaction inverter 24 for bringing the torque of the reaction motor 22 closer to the target torque Ts* is output to the reaction inverter 24 (S66).

[0053] On the other hand, when the PU52 makes an affirmative determination in the process of S56, it ends the synchronous control (S68). When the PU52 completes the processes of S66 and S68, it temporarily ends the series of processes shown in Fig. 7.

[0054] "Process for dealing with steering intervention" The above N-point learning process and synchronization control are processes assuming that the driver does not operate the steering wheel 12. The PU52 executes the following processes to handle unexpected situations where the driver intervenes in steering during the execution of the N-point learning process and the synchronization control.

[0055] Fig. 8 shows the procedure of the process executed by the PU52. The series of processes shown in Fig. 8 is realized by the PU52 repeatedly executing the program stored in the storage device 54, for example, at a predetermined cycle.

[0056] In the series of processes shown in Fig. 8, the PU52 first determines whether either the N-point learning process or the synchronization control is being executed (S70). If the PU52 determines that either is being executed (S70: YES), it determines whether there is an abnormality in the torque sensor 56 (S72). For example, the PU72 may determine that there is an abnormality when the output voltage of the torque sensor 56 is out of the predetermined range. If the PU52 determines that there is no abnormality in the torque sensor 56 (S72: NO), it acquires the steering torque Th (S74). Then the PU52 determines whether the absolute value of the steering torque Th is greater than the threshold value Thth (S76). The threshold value Thth is set according to the lower limit value of the torque applied when the driver operates the steering wheel 12. If the PU52 determines that it is greater than the threshold value Thth (S76: YES), it determines that the driver is intervening in steering (S86). Then the PU52 prompts the driver to stop intervening in steering by operating the user interface 69 shown in Fig. 1 (S88). For example, if the user interface 69 includes a display, the process of S88 may be a process of displaying visual information on the display. Also, for example, if the user interface 69 includes a speaker, the process of S88 may be a process of outputting an audio signal.

[0057] On the other hand, when determining that there is an abnormality in the torque sensor 56 (S72: YES), the PU52 determines whether it is at the start of the N-point learning mode or the synchronous control mode (S78). When determining that it is at the start of any of the above modes (S78: YES), the PU52 sets the required time Td required until the end of the mode (S80). Here, the required time Td for N-point learning may be, for example, a predetermined fixed value. Further, the PU52 may set the required time Td for synchronous control according to the difference between the target steering angle θh*0 and the steering angle θh. Also, for example, the required time Td for synchronous control may be a predetermined fixed value.

[0058] When the PU52 completes the process of S80 and when making a negative determination in the process of S78, the counter T is incremented (S82). The counter T is a variable that measures the execution time of the N-point learning process or synchronous control. Next, the PU52 determines whether the logical product of the following conditions (D) to (F) is true (S84).

[0059] Condition (D): A condition that the absolute value of the difference between the steering angle θh and the target steering angle θh* is greater than a predetermined value θhth. Condition (E): A condition that the absolute value of the difference between the steering angular velocity ωh and the target steering angular velocity ωh* is greater than a predetermined value ωhth. The steering angular velocity ωh is the change rate of the steering angle θh. The steering angular velocity ωh is calculated by the PU52 based on the steering angle θh as an input variable.

[0060] Condition (F): A condition that the value of the counter T is greater than the required time Td + α. When the PU52 determines that the above logical product is true (S84: YES), it proceeds to the process of S86. Note that when the PU52 completes the process of S88 and when making a negative determination in the processes of S70, S76, and S84, the series of processes shown in FIG. 8 is temporarily terminated.

[0061] "Operations and Effects of the Present Embodiment" At startup, PU52 determines whether the steering-side N-point learning data 54a is stored in the storage device 54. When PU52 determines that the steering-side N-point learning data 54a is not stored, it executes the N-point learning process by operating the reaction motor 22. Also, at startup, when the steering angle θh and the equivalent steering angle θp do not match, PU52 displaces the steering shaft 14 by operating the reaction motor 22 so that the steering angle θh and the equivalent steering angle θp match.

[0062] Here, when the driver touches the steering wheel 12, it becomes difficult to complete the N-point learning process and the synchronization control. Therefore, when the absolute value of the steering torque Th becomes equal to or greater than the threshold value Thth, PU52 determines that the driver is touching the steering wheel 12 and alerts the driver. Also, when there is an abnormality in the torque sensor 56, PU52 determines that the driver is touching the steering wheel 12 based on the logical product of the above conditions (D) to (F) being true. Thereby, even when there is an abnormality in the torque sensor 56, it is possible to determine whether the driver is touching the steering wheel 12.

[0063] <Corresponding relationship> The correspondence between the matters in the above-described embodiment and the matters described in the column of "Means for Solving the Problems" is as follows. Below, the correspondence is shown for each number of the solution means described in the column of "Means for Solving the Problems". [1] The displacement process corresponds to the processes of S34 and S36 and the processes of S64 and S66. The intervention determination process corresponds to the process of S84. The detection value of the sensor corresponds to the steering angle θh. [2] The steering intervention process corresponds to determining that there was a steering intervention when the condition (D) in the process of S84 is satisfied. [3] The steering intervention process corresponds to determining that there was a steering intervention when the condition (E) in the process of S80 is satisfied. [4] The steering intervention process corresponds to determining that there was a steering intervention when the condition (F) in the process of S80 is satisfied. [5, 6] The alignment process corresponds to the processes of S64 and S66. The alert process corresponds to the process of S88. [7] The end fitting process corresponds to the processes of S34 and S36 executed in the right turn mode. The end determination process corresponds to the process of S26. The maximum displacement variable acquisition process corresponds to the process of S30. The midpoint learning process corresponds to the process of S40. The alert process corresponds to the process of S88.

[0064] <Other Embodiments> Note that this embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0065] "Regarding the Intervention Determination Process" · The intervention determination process is not limited to the process of determining that there is a steering intervention when the logical sum of the above conditions (D) to (F) is true. For example, the intervention determination process may be a process of determining that there is a steering intervention when the logical sum of the above conditions (D) and (E) is true. Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical sum of the above conditions (E) and (F) is true. Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical sum of the above conditions (D) and (F) is true. Also, for example, the intervention determination process may be a process of determining whether the above condition (D) is satisfied. Also, for example, the intervention determination process may be a process of determining whether the above condition (E) is satisfied. Also, for example, the intervention determination process may be a process of determining whether the above condition (F) is satisfied.

[0066] Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical product of the above conditions (D) to (F) is true. Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical product of the above conditions (D) and (E) is true. Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical product of the above conditions (E) and (F) is true. Also, for example, the intervention determination process may be a process of determining that there is a steering intervention when the logical product of the above conditions (D) and (F) is true.

[0067] "Regarding displacement processing" · It is not essential for the displacement processing to include synchronous control and N-point learning processing. The displacement processing may be, for example, either one of them.

[0068] "Regarding the steering angle variable" ·The steering angle variable is not limited to the steering angle θh calculated by the integration process of the rotation angle θa. For example, when a dedicated sensor for detecting the rotation angle of the steering shaft 14 is provided, the steering angle variable may be the detected value of that sensor. Also, for example, the steering angle variable may be the detected value of a sensor for detecting the rotation speed of the reaction force motor 22.

[0069] "Regarding the end fitting process" ·The end fitting process is not limited to the process of setting the target steering angular velocity to a constant value. For example, in the end fitting process, the target steering angular velocity may be decreased midway. Thereby, a suitable compromise can be achieved between reducing the impact when reaching the right upper limit value and quickly reaching the right upper limit value. Also, the number of times the target steering angular velocity is changed in the end fitting process does not have to be 1 time, and may be 2 times or more.

[0070] ·The condition for determining that PU52 has reached the right upper limit value is not limited to the condition that the logical product of the above conditions (A) to (C) is true and continues for a certain period of time. The condition for determining that PU52 has reached the right upper limit value may be, for example, the condition that the above conditions (A) and (B) hold for a certain period of time. Also, for example, the condition for determining that PU52 has reached the right upper limit value may be the condition that the above conditions (B) and (C) hold for a certain period of time. Also, for example, when the threshold Ith is set as the value for determining that the windup phenomenon of the integral term has occurred, the condition for determining that PU52 has reached the right upper limit value may be the condition that the above conditions (A) and (C) hold.

[0071] ·It is not essential to execute the process of substituting the steering angle θh into the target steering angle θh* when it is determined that PU52 has reached the right upper limit value. For example, when it is determined that PU52 has reached the right upper limit value, PU52 may gradually decrease the target steering angle θh* according to a predetermined amount Δ.

[0072] ·It is not essential that the control amount of the feedback control in the end fitting process is the steering angle θh. For example, the control amount of the feedback control in the end fitting process may be the change rate of the steering angle θh.

[0073] ·It is not essential that the end fitting process is a process of rotating the steering shaft 14 clockwise. For example, the end fitting process may be a process of rotating the steering shaft 14 counterclockwise.

[0074] ·It is not essential that the end fitting process consists of either one of the process of rotating the steering shaft 14 clockwise and the process of rotating the steering shaft 14 counterclockwise. For example, the end fitting process may include both the process of rotating the steering shaft 14 clockwise and the process of rotating the steering shaft 14 counterclockwise.

[0075] "Regarding the midpoint learning process" ·In FIG. 6, an example is shown in which PU52 repeatedly executes the processes of S38 and S40 until a positive determination is made in the process of S42 in the midpoint movement mode, but it is not limited to this. For example, when the process of S30 is performed, PU52 may execute the processes of S38 and S40 only once and store the midpoint θhmd in the storage device 54.

[0076] ·In the process of FIG. 6, instead of the processes of S38 and S40, PU52 may execute a process of substituting "θhR - θLR / 2" into the midpoint θhmd. ·It is not essential that the midpoint learning process is a process of learning the midpoint of the steering angle θh obtained by integrating the rotation angle θa. For example, when a dedicated sensor for detecting the rotation angle of the steering shaft 14 is provided, it may be a process of learning the midpoint thereof.

[0077] · For example, as described in the column "End fitting process", when the end fitting process includes both a process of rotating the steering shaft 14 clockwise and a process of rotating it counterclockwise, the midpoint learning process may be the following process. That is, the midpoint learning process may be a process of substituting the average value of the right upper limit value obtained by the clockwise rotation process and the left upper limit value obtained by the counterclockwise rotation process into the midpoint θhmd.

[0078] "Regarding the steering control device" · The reaction force control device 50 and the steering control device 60 may be integrally formed. · The steering control device is not limited to one that executes software processing. For example, at least a part of the processing executed in the above embodiment may be executed by hardware processing, and a dedicated hardware circuit such as an ASIC may be provided. That is, the steering control device may include a processing circuit having any of the following configurations (a) to (c). (a) A processing circuit including a processing device that executes all of the above processing according to a program and a program storage device such as a storage device that stores the program. (b) A processing circuit including a processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A processing circuit including a dedicated hardware circuit that executes all of the above processing. Here, there may be a plurality of software execution devices including a processing device and a program storage device. Also, there may be a plurality of dedicated hardware circuits.

[0079] "Regarding the device for restricting the rotation of the steering shaft 14" · The device for restricting the rotation of the steering shaft 14 is not limited to the device exemplified in the above embodiment. For example, it may not be provided with an intermediate stopper that is carried along by the end stopper 100.

Explanation of reference numerals

[0080] 10... Steering device 12... Steering wheel 14... Steering shaft 20… Reaction actuator 22… Reaction motor 24… Inverter for reaction force 26… Reduction mechanism for reaction force 30… Steering actuator 32… Rack shaft 34… Steering wheel 42… Steering motor 44… Inverter for steering 46… Steering transmission mechanism 48… Conversion mechanism 50… Reaction force control device 60… Steering control device

Claims

1. In a steering control device that targets a reaction force motor that applies a reaction force to a steering shaft, configured to execute displacement processing and intervention determination processing in a state where power transmission between the steering shaft and the steered wheels is interrupted, the displacement processing is a process of operating the reaction force motor to rotate the steering shaft by a predetermined amount on the premise that the driver does not perform a rotational operation of the steering shaft, the intervention determination processing is a process of determining that there is a steering intervention that obstructs the displacement processing by the driver based on the value of a steering angle variable as an input variable, the steering control device, wherein the steering angle variable is a variable indicating the displacement of the steering shaft based on the detection value of a sensor.

2. The displacement processing includes a process of operating the reaction force motor by an operation amount of control in which the steering angle is a control amount and the target steering angle is a target value of the control amount, the steering angle is the rotation angle of the steering shaft, The steering control device according to claim 1, wherein the intervention determination processing includes a process of determining that there is the steering intervention when the degree of deviation between the steering angle and the target steering angle is equal to or more than a predetermined value.

3. The displacement processing includes a process of displacing the steering angle at a target steering angular velocity, the steering angle is the rotation angle of the steering shaft, The steering control device according to claim 1, wherein the intervention determination processing includes a process of determining that there is the steering intervention when the degree of deviation between the steering angular velocity and the target steering angular velocity is equal to or more than a predetermined value.

4. The steering control device according to claim 1, wherein the intervention determination processing determines that there is the steering intervention when the execution time of the displacement processing exceeds the required time for completion of the displacement processing by a predetermined amount or more.

5. configured to execute a warning process, the displacement processing includes alignment processing that is a process of rotating the steering shaft to align the steering angle and the steered angle when the steered angle of the steered wheels and the steering angle do not match, the steering angle is the rotation angle of the steering shaft, The steering control device according to claim 1, wherein the warning process includes a process of warning that the alignment processing is being executed when it is determined that there is the steering intervention during the execution of the alignment processing.

6. The steering control device according to claim 5, configured to execute the alignment process on the condition that the steering angle and the steering angle do not match when the vehicle start switch is switched from the off state to the on state.

7. configured to execute an end fitting process, an end determination process, a maximum displacement variable acquisition process, a midpoint learning process, and a caution notification process, The end fitting process is a process of displacing the steering shaft to the maximum extent to at least one of the right rotation side and the left rotation side by the operation of the reaction force motor. The end determination process is a process of determining whether the steering shaft has been displaced to the maximum extent. The maximum displacement variable acquisition process is a process of acquiring the value of the maximum displacement variable. The maximum displacement variable is a variable obtained based on being determined to be displaced to the maximum extent by the end determination process. The midpoint learning process is a process of learning the midpoint of the rotation angle of the steering shaft based on the value of the maximum displacement variable as an input variable. The displacement process includes the end fitting process. The caution notification process includes a process of notifying that the end fitting process is being executed when it is determined that there is steering intervention during the execution of the end fitting process. The steering control device according to claim 1.

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