Steering method and steering device

Abstract

In a method for steering a steering wheel of a steering vehicle, a steering wheel steering angle is detected (S1); the actual steering angle of the steering wheel, i.e., the actual steering angle, is detected (S2); a target steering angle of the steering wheel is calculated based on the detected steering angle (S3); based on the difference between the actual steering angle and the target steering angle, a steering force command value for making the actual steering angle consistent with the target steering angle is calculated, and the phase of the steering force command value is delayed relative to the detected steering angle (S4, S5); and a steering force for steering the steering wheel is generated based on the steering force command value after the delayed phase (S6).

Description

Technical Field

[0001] The invention relates to a steering method and a steering device. Background Art

[0002] Patent Document 1 describes a steering angle control device including a steering member for steering a vehicle and a steering device including steered wheels, calculates a steering angle corresponding to a steering angle, and controls a steering actuator based on the calculated steering angle.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-43391

[0006] Problems to be Solved by the Invention

[0007] When a target steering angle is set based on the steering angle of the steering wheel steered by the driver and a steering force is generated based on the actual steering angle of the steering wheel, i.e., the difference between the actual steering angle and the target steering angle, the vehicle movement becomes responsive to the driver's steering operation faster, and the driver may feel uncomfortable. Summary of the invention

[0008] An object of the present invention is to reduce the driver's discomfort caused by a quick response of vehicle behavior to a steering operation in a steering device that steers a steered wheel with a steering force based on a difference between an actual steering angle and a target steering angle.

[0009] In a steering method for a steering wheel of a steering vehicle according to one embodiment of the present invention, the steering angle of the steering wheel is detected, the actual steering angle of the steering wheel, i.e., the actual steering angle, is detected, a target steering angle of the steering wheel is calculated based on the detected steering angle, a steering force command value for making the actual steering angle consistent with the target steering angle is calculated based on the difference between the actual steering angle and the target steering angle, the phase of the steering force command value is delayed relative to the detected steering angle, and a steering force for steering the steering wheel is generated based on the steering force command value after the delayed phase.

[0010] Effects of the Invention

[0011] According to the present invention, in a steering device that steers a steered wheel with a steering force based on a difference between an actual steering angle and a target steering angle, it is possible to reduce the driver's discomfort caused by a quick response of the vehicle behavior to the steering operation.

[0012] The objects and advantages of the present invention are achieved by using the elements and combinations thereof shown in the claims. Both the above general description and the following detailed description are merely illustrative and explanatory, and should not be understood to limit the present invention as the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A It is a schematic configuration diagram of an example of a steering device according to an embodiment.

[0014] Figure 1B yes Figure 1A A block diagram of an example of the functional configuration of a controller is shown.

[0015] Figure 2A This is a schematic diagram showing an example of the temporal change of the steering angle.

[0016] Figure 2B is with Figure 2A Schematic diagram of the steering angle corresponding to the steering angle.

[0017] Figure 2C is used to generate Figure 2B Schematic diagram of the steering force as the steering angle changes.

[0018] Figure 2D Is Figure 2B Schematic diagram of the self-aligning torque (SAT) generated by the change in steering angle.

[0019] Figure 2E Is Figure 2B Schematic diagram of the yaw rate caused by the change of steering angle.

[0020] Figure 3A is to make the phase relative to Figure 2A Schematic diagram of the steering angle with a steering angle delay.

[0021] Figure 3B is used to generate Figure 3A Schematic diagram of the steering force as the steering angle changes.

[0022] Figure 3C Is Figure 3A Schematic diagram of the SAT generated by the change of steering angle.

[0023] Figure 3D Is Figure 3A Schematic diagram of the yaw rate caused by the change of steering angle.

[0024] Figure 4 This is a block diagram showing an example of the functional configuration of the steering control unit according to the first embodiment.

[0025] Figure 5 This is a flowchart of an example of the steering method according to the first embodiment.

[0026] Fig. 6A This is a block diagram showing an example of the functional configuration of the delay unit according to the second embodiment.

[0027] Figure 6B yes Fig. 6A An explanatory diagram of an example of a limit value of a limiter.

[0028] Figure 7 This is a block diagram showing an example of the functional configuration of a modification of the delay unit according to the second embodiment.

[0029] Fig. 8A This is a block diagram showing an example of the functional configuration of a steering control unit according to the third embodiment.

[0030] Figure 8B yes Fig. 8A An explanatory diagram of an example of the gain G of the gain setting unit.

[0031] Fig.9A This is a block diagram showing an example of the functional configuration of a modified example of the steering control unit according to the third embodiment.

[0032] Fig. 9B yes Fig.9A An explanatory diagram of an example of the gain G of the gain setting unit.

[0033] Fig. 10A This is a block diagram showing an example of the functional configuration of a modified example of the steering control unit according to the third embodiment.

[0034] Fig. 10B yes Fig. 10A An explanatory diagram of an example of the gain G of the gain setting unit.

[0035] Fig.11A This is a block diagram showing an example of the functional configuration of a modified example of the steering control unit according to the third embodiment.

[0036] Fig. 11B yes Fig.11A An explanatory diagram of an example of the gain G of the gain setting unit.

[0037] Fig. 12A This is a block diagram showing an example of the functional configuration of a modified example of the steering control unit according to the third embodiment.

[0038] Fig. 12B yes Fig. 12A An explanatory diagram of an example of the gain G of the gain setting unit.

[0039] Fig.13 This is a block diagram showing an example of the functional configuration of a steering control unit according to the fourth embodiment.

[0040] Fig.14 This is a flowchart of an example of the steering method according to the fourth embodiment.

[0041] Fig.15 This is a block diagram showing an example of a functional configuration of a modified example of the steering control unit according to the fourth embodiment. DETAILED DESCRIPTION

[0042] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. In addition, each of the accompanying drawings is schematic and may differ from reality. In addition, the embodiments of the present invention shown below are illustrative embodiments of devices and methods for concretizing the technical ideas of the present invention, and the technical ideas of the present invention do not specify the structure and configuration of the constituent parts as follows. The technical ideas of the present invention can be variously modified within the technical scope specified by the claim items recorded in the scope of the claims.

[0043] (First Embodiment)

[0044] (structure)

[0045] Figure 1A The schematic diagram is a diagram of an example of a vehicle steering device according to the first to fourth embodiments. The steering device according to the embodiment includes a steering unit 31 that receives a steering input from a driver, a steering unit 32 that steers left and right front wheels 34FL and 34FR as steering wheels, a backup clutch 33, and a controller 11.

[0046] This steering device adopts a steer-by-wire (SBW) system, and when the backup clutch 33 is released, the steering unit 31 is mechanically separated from the steering unit 32. In the following description, the left and right front wheels 34FL and 34FR may be referred to as "steering wheels 34".

[0047] The steering unit 31 includes a steering wheel 31 a , a column shaft 31 b , a reaction force actuator 12 , a first drive circuit 13 , a torque sensor 16 , and a steering angle sensor 19 .

[0048] On the other hand, the steering unit 32 includes a pinion shaft 32 a , a steering gear 32 b , a rack 32 c , a steering rack 32 d , the steering actuator 14 , a second drive circuit 15 , and a steering angle sensor 35 .

[0049] The steering wheel 31a of the steering unit 31 is applied with reaction torque by the reaction force actuator 12, and rotates in response to the input of the steering torque applied by the driver. In this specification, the reaction torque applied to the steering wheel by the actuator is sometimes referred to as "steering reaction torque".

[0050] The column shaft 31 b rotates integrally with the steering wheel 31 a.

[0051] On the other hand, the steering gear 32b of the steering unit 32 meshes with the rack 32c, and the steering wheel 34 is steered according to the rotation of the pinion shaft 32a. As the steering gear 32b, for example, a rack-and-pinion type steering gear or the like can be adopted.

[0052] The backup clutch 33 is provided between the column shaft 31b and the pinion shaft 32a. Moreover, the backup clutch 33 mechanically separates the steering unit 31 and the steering part 32 when it is in the released state, and mechanically connects the steering unit 31 and the steering part 32 when it is in the connected state. In addition, the backup clutch 33 is normally in the released state when the vehicle is running or when the ignition switch is turned on. For example, when some abnormality occurs in the system such as an abnormality of the steering actuator 14 or the reaction force actuator 12, or when the ignition switch of the vehicle is turned off (for example, when parking), it is in the connected state, and is usually in the released state. Therefore, the following description is a case where the backup clutch 33 is in the released state and the steering wheel 31a is mechanically separated from the steering unit 32.

[0053] The torque sensor 16 detects the steering torque Ts transmitted from the steering wheel 31 a to the column shaft 31 b.

[0054] The vehicle speed sensor 17 detects the wheel speed of the vehicle on which the steering device according to the embodiment is mounted, and calculates the vehicle speed Vv of the vehicle based on the wheel speed.

[0055] The steering angle sensor 19 detects a column shaft rotation angle, that is, a steering angle θs (steering wheel angle) of the steering wheel 31 a .

[0056] The steering angle sensor 35 detects an actual steering angle θt which is an actual steering angle of the steered wheels 34 .

[0057] The controller 11 is an electronic control unit (ECU) that performs steering control of the steering wheel and reaction force control of the steering wheel. In this specification, "reaction force control" refers to the control of the steering reaction force torque applied to the steering wheel 31a by an actuator such as the reaction force actuator 12. The controller 11 includes peripheral components such as a processor 20 and a storage device 21. The processor 20 can be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).

[0058] The storage device 21 may include a semiconductor storage device, a magnetic storage device, or an optical storage device. The storage device 21 may include a register, a cache memory, a ROM (Read Only Memory) used as a main storage device, and a RAM (Random Access Memory) and other memories.

[0059] Alternatively, the controller 11 may be realized by a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller 11 includes a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0060] Figure 1B 1 is a block diagram showing a functional configuration example of the controller 11. The controller 11 includes a reaction force control unit 40 and a steering control unit 41. The functions of the reaction force control unit 40 and the steering control unit 41 can be realized by, for example, the processor 20 executing a computer program stored in the storage device 21 of the controller 11.

[0061] The reaction force control unit 40 calculates a reaction force command value fs, which is a command value of a steering reaction torque (rotational torque applied to the steering wheel 31 a , hereinafter also referred to as reaction force torque) applied to the steering wheel, based on the steering angle θs detected by the steering angle sensor 19 .

[0062] The reaction force control unit 40 outputs the reaction force command value fs to the first drive circuit 13. The first drive circuit 13 drives the reaction force actuator 12 based on the reaction force command value fs.

[0063] The reaction force actuator 12 may be, for example, an electric motor. The reaction force actuator 12 has an output shaft disposed coaxially with the column shaft 31 b.

[0064] The reaction force actuator 12 outputs the rotational torque applied to the steering wheel 31a to the column shaft 31b according to the command current output from the first drive circuit 13. The application of the rotational torque generates a steering reaction force torque on the steering wheel 31a.

[0065] The first drive circuit 13 controls the command current output to the reaction force actuator 12 by torque feedback that makes the actual steering reaction force torque estimated from the drive current of the reaction force actuator 12 consistent with the reaction force torque represented by the reaction force command value fs output from the reaction force control unit 40. Alternatively, the command current output to the reaction force actuator 12 may be controlled by current feedback that makes the drive current of the reaction force actuator 12 consistent with the drive current equivalent to the reaction force command value fs.

[0066] The steering control unit 41 calculates a steering force command value ft which is a command value of a steering torque for steering the steered wheels 34 based on the steering angle θs of the steering wheel 31 a , the actual steering angle θt of the steered wheels 34 , and the vehicle speed Vv.

[0067] Specifically, the steered control unit 41 calculates a target steered angle θtr which is a target value of the steered angle of the steered wheels 34 based on the steering angle θs.

[0068] The steering control unit 41 may change the angle ratio Ra=θtr / θs, which is the ratio of the target steering angle θtr to the steering angle θs, at least according to the vehicle speed Vv. For example, when the vehicle speed Vv is low, the angle ratio Ra may be set to a relatively large value to improve the return performance of the steering wheel 31a, and when the vehicle speed Vv is high, the angle ratio Ra may be set to a relatively small value to improve the steering stability.

[0069] The steering control unit 41 calculates a steering force command value ft for making the actual steering angle θt consistent with the target steering angle θtr based on the difference (θtr-θt) between the actual steering angle θt and the target steering angle θtr. The larger the difference (θtr-θt) between the actual steering angle θt and the target steering angle θtr is, the larger the value of the calculated steering force command value ft is. For example, the steering force command value ft is calculated by multiplying the difference (θtr-θt) between the actual steering angle θt and the target steering angle θtr by a predetermined gain. Alternatively, the steering force command value ft corresponding to the difference (θtr-θt) between the actual steering angle θt and the target steering angle θtr may be stored in advance as a steering force map, and the steering force command value ft may be calculated based on the calculated (θtr-θt) with reference to the steering force map.

[0070] The steering control unit 41 outputs the steering force command value ft to the second drive circuit 15. The second drive circuit 15 drives the steering actuator 14 based on the steering force command value ft.

[0071] The steering actuator 14 may be, for example, an electric motor such as a brushless motor. The output shaft of the steering actuator 14 is connected to the rack 32c via a speed reducer.

[0072] The steering actuator 14 outputs a steering torque for steering the steered wheels 34 to the steering rack 32 d based on the command current output from the second drive circuit 15 .

[0073] The second drive circuit 15 controls the command current output to the steering actuator 14 by performing torque feedback so that the actual steering torque estimated from the driving current of the steering actuator 14 coincides with the steering torque represented by the steering force command value ft output from the steering control unit 41. Alternatively, the command current output to the steering actuator 14 may be controlled by performing current feedback so that the driving current of the steering actuator 14 coincides with the driving current corresponding to the steering force command value ft.

[0074] When a steering force is generated based on the difference (θtr-θt) between the actual steering angle θt and the target steering angle θtr to make the actual steering angle θt and the target steering angle θtr consistent with each other, the vehicle behavior becomes more responsive to the driver's steering operation, and the driver may feel uncomfortable. Figure 2A to Figure 2E State the reason.

[0075] Figure 2A is a schematic diagram of the steering angle θs that changes due to the driver's steering operation, Figure 2B is with Figure 2A Schematic diagram of the steering angle θt corresponding to the steering angle θs, Figure 2C is used to generate Figure 2B Schematic diagram of the steering force with the change of steering angle, Figure 2D It is due to Figure 2B Schematic diagram of the self-aligning torque (SAT) generated by the change of the steering angle. Figure 2E It is due to Figure 2B Schematic diagram of the yaw rate caused by the change of steering angle.

[0076] In the steer-by-wire system, servo control is performed so that the target steering angle θtr calculated based on the steering angle θs is consistent with the actual steering angle θt. Therefore, compared with the conventional steering device that transmits the steering torque to the steering wheel through the connection of the shaft, the phase delay of the steering angle θt with respect to the steering angle θs becomes smaller ( Figure 2A as well as Figure 2B ).

[0077] Immediately after the steering angle θt starts to change, the angular difference between the direction of the steered wheel 34 and the advancing direction of the steered wheel 34 increases. Therefore, when the actual steering angle θt follows the target steering angle θtr with a small delay, the lateral force generated at the tire increases sharply.

[0078] Therefore, after the steering angle θt starts to change, Figure 2C , Figure 2D As shown, the steering force and the righting moment increase sharply.

[0079] As a result, if Figure 2E As shown in FIG. 1 , immediately after the steering angle θt starts to change, the yaw rate increases rapidly, and the vehicle moves faster relative to the steering force applied by the driver to the steering wheel 31 a , which may cause the driver to feel uncomfortable.

[0080] Therefore, the steering control unit 41 of the embodiment delays the phase of the steering force command value ft relative to the steering angle θs. Figure 3A As shown by the solid line of , the steering angle θt can be delayed relative to the steering angle θs immediately after the steering angle θt starts to change.

[0081] Figure 3A to Figure 3D The solid line is relative to Figure 2A The diagram shows the steering angle θt, steering force, SAT and yaw rate when the steering angle θs delays the phase of the steering force command value ft. For comparison, the case where the phase is not delayed is shown by a dashed line.

[0082] like Figure 3A As shown in FIG. 1 , as a result of delaying the phase of the steering force command value ft, the steering angle θt is delayed, so that changes in the steering force, SAT, and yaw rate can be slowed down. Therefore, the vehicle movement can be suppressed from becoming faster with respect to the steering force applied by the driver, and the driver's discomfort can be reduced.

[0083] The steering control unit 41 will be further described below.

[0084] Figure 4 1 is a block diagram showing an example of the functional configuration of the steered steering control unit 41 according to the first embodiment. The steered steering control unit 41 includes a steered steering angle setting unit 50 , a delay unit 52 , and a steered steering angle control unit 53 .

[0085] The steering angle setting unit 50 calculates the target steering angle θtr based on the steering angle θs. For example, the steering angle setting unit 50 multiplies the steering angle θs by the angle ratio Ra to calculate the target steering angle θtr.

[0086] The steering angle setting unit 50 may dynamically change the angle ratio Ra. For example, the steering angle setting unit 50 may change the angle ratio Ra at least according to the vehicle speed Vv.

[0087] For example, when the vehicle speed Vv is low, the angle ratio Ra may be set to a relatively large value to improve the return performance of the steering wheel 31a, and when the vehicle speed Vv is high, the angle ratio Ra may be set to a relatively small value to improve the steering stability.

[0088] Alternatively, the target steering angle θtr with respect to the steering angle θs may be stored in advance as a steering angle map, and the target steering angle θtr may be calculated based on the detected actual steering angle θs with reference to the steering angle map. Alternatively, a plurality of steering angle maps may be stored in correspondence with the vehicle speed Vv, so that the relationship between the target steering angle θtr and the steering angle θs varies in accordance with the vehicle speed Vv.

[0089] The steering angle setting unit 50 outputs the target steering angle θtr to the delay unit 52. The delay unit 52 delays the phase of the target steering angle θtr output by the steering angle setting unit 50. The delay unit 52 outputs the delayed target steering angle θtrd to the steering angle control unit 53.

[0090] The steer angle control unit 53 calculates the steer force command value ft for making the actual steer angle θt coincide with the target steer angle θtrd based on the difference between the phase-delayed target steer angle θt and the actual steer angle θt.

[0091] In this way, the delay unit (delay means) 52 delays the phase of the target steering angle θtr, thereby delaying the phase of the steering force command value ft calculated by the steering angle control unit 53 with respect to the steering angle θs.

[0092] The delay unit 52 may be, for example, a phase lag filter (delay filter) that delays the phase of the input signal. The amount of phase delay in the delay unit 52 may be set in advance through experiments or the like.

[0093] Alternatively, the delay unit 52 may delay the phase of the target steering angle θtr by outputting a signal obtained by adding an integral term of the target steering angle θtr and a proportional term of the target steering angle θtr, as in a second embodiment described below.

[0094] (action)

[0095] Next, refer to Figure 5 An example of the steering method according to the first embodiment will be described.

[0096] In step S1 , the steering angle sensor 19 detects the steering angle θs of the steering wheel 31 a .

[0097] In step S2 , the steering angle sensor 35 detects the actual steering angle θt of the steered wheel 34 .

[0098] In step S3 , the steering angle setting unit 50 calculates a target steering angle θtr based on the steering angle θs.

[0099] In step S4 , the delay unit 52 delays the phase of the target steering angle θtr outputted from the steering angle setting unit 50 .

[0100] In step S5 , the steerage angle control unit 53 calculates the steerage force command value ft based on the difference between the target steerage angle θtrd and the actual steerage angle θt after the phase delay.

[0101] In step S6 , the second drive circuit 15 drives the steering actuator 14 based on the steering force command value ft.

[0102] (Effects of the First Embodiment)

[0103] (1) The steering angle sensor 19 detects the steering angle θs of the steering wheel 31a. The steering angle sensor 35 detects the actual steering angle θt of the steered wheel 34. The steering angle setting unit 50 calculates the target steering angle θtr based on the steering angle θs. The delay unit 52 delays the phase of the target steering angle θtr relative to the steering angle θs.

[0104] The steering angle control unit 53 calculates a steering force command value ft for making the actual steering angle θt coincide with the target steering angle θtrd based on the difference between the target steering angle θtrd and the actual steering angle θt after the phase delay. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs. The second drive circuit 15 and the steering actuator 14 generate a steering force for steering the steered wheel 34 based on the steering force command value ft after the phase delay.

[0105] This can reduce the driver's discomfort caused by the quick response of the vehicle behavior to the steering operation.

[0106] (2) By delaying the phase of the target steering angle θtr calculated based on the steering angle θs, the phase of the steering force command value ft can be delayed relative to the steering angle θs. This can prevent the vehicle behavior from responding too quickly to the steering force applied by the driver, thereby reducing the driver's discomfort.

[0107] (3) The delay unit 52 may be a delay filter. This makes it possible to delay the phase of the steering force command value ft with respect to the steering angle θs.

[0108] (Second Embodiment)

[0109] The second embodiment will describe an example of the delay unit 52 of the steer control unit 41. The delay unit 52 of the second embodiment delays the phase of the target steer angle θtr by adding an integral term of the target steer angle θtr set by the steer angle setting unit 50 to a proportional term of the target steer angle θtr.

[0110] Reference Fig. 6A The delay section 52 includes a gain multiplication section 60 , a delay element 61 , adders 62 and 64 , and a limiter 63 .

[0111] The target steering angle θtr set by the steering angle setting unit 50 is distributed into K×θtr and (1-K)×θtr by a distribution coefficient K: (1-K). Here, K is a coefficient greater than 0 and less than 1, for example, K=0.5. In this case, the target steering angle θtr is equally divided. The distribution coefficient K may be a value other than 0.5, and may be appropriately set according to the desired delay.

[0112] The steering angle setting unit 50 may distribute the target steering angle θtr into K×θtr and (1-K)×θtr by multiplying the target steering angle θtr by a distribution coefficient K: (1-K). In addition, for example, the steering angle setting unit 50 may output the target steering angle θtr to the delay unit 52, and the delay unit 52 may multiply the target steering angle θtr by a gain K and (1-K) to distribute the target steering angle θtr into K×θtr and (1-K)×θtr. Hereinafter, K×θtr and (1-K)×θtr are referred to as “distributed target steering angles”.

[0113] The gain multiplication unit 60 multiplies the integral gain Ki by the distributed target steering angle (1-K)×θtr, and outputs the multiplication result.

[0114] The delay element 61 holds a past value of the integrated value of the output (Ki×(1−K)×θtr) of the gain multiplication unit 60 .

[0115] The adder 62 integrates the output (Ki×(1−K)×θtr) of the gain multiplication unit 60 by adding the output (Ki×(1−K)×θtr) of the gain multiplication unit 60 to the past value of the integrated value.

[0116] Here, the coefficient Ki×(1-K) can also be regarded as an integral gain. Therefore, the integral value of the output (Ki×(1-K)×θtr) integrated by the adder 62 can be regarded as an integral term of the target steering angle θtr.

[0117] The limiter 63 limits the magnitude (ie, the absolute value) of the integral term of the target steering angle θtr to a limit value or less.

[0118] For example, the limiter 63 may limit the magnitude (ie, absolute value) of the integral term of the target steering angle θtr to be equal to or less than the limit value by using the limit value that changes according to the target steering angle θtr.

[0119] Reference Figure 6B The larger the target steering angle θtr is, the larger the limit value is. Similar to the target steering angle θtr, the limit value may be changed in accordance with the vehicle speed Vv.

[0120] Therefore, even if the target steering angle θtr is maintained at a non-zero angle while the steering state is maintained, the integral term of the target steering angle θtr can be prevented from continuing to increase, and the output of the delay unit 52 (i.e., the target steering angle θtrd after the phase is delayed) can be fixed to an angle corresponding to the target steering angle θtr.

[0121] Reference Fig. 6A The adder 64 adds the integral term of the target steering angle θtr output from the limiter 63 to the distributed target steering angle K×θtr (ie, the proportional term of the target steering angle θtr), thereby calculating a phase-delayed target steering angle θtrd.

[0122] Figure 7 This is a block diagram of an example of the functional structure of a modification of the delay unit 52 of the second embodiment. The delay unit 52 of the modification includes a subtractor 65. The subtractor 65 inputs the difference obtained by subtracting the past value of the integrated value of the output (Ki×(1-K)×θtr) of the gain multiplication unit 60 from the allocated target steering angle (1-K)×θtr to the gain multiplication unit 60.

[0123] Therefore, when the target steering angle θtr is constant (i.e., the time variation disappears), and the integral value of the allocated target steering angle (1-K)×θtr and the output of the gain multiplication unit 60 (Ki×(1-K)×θtr) is equal, the input to the gain multiplication unit 60 is eliminated and the integral value does not change.

[0124] Therefore, the gain multiplication unit 60, the delay element 61, the adder 62, and the subtractor 65 calculate only the integral term of the variation component of the target steering angle θtr.

[0125] Therefore, even if the target steering angle θtr is maintained at a non-zero angle while the steering state is maintained, the integral term of the target steering angle θtr can be prevented from continuing to increase, and the output of the delay unit 52 (i.e., the target steering angle θtrd after the phase is delayed) can be fixed to an angle corresponding to the target steering angle θtr.

[0126] (Effects of the Second Embodiment)

[0127] (1) The delay unit 52 may delay the phase of the target steering angle θtr by adding an integral term of the target steering angle θtr calculated based on the steering angle θs to a proportional term of the target steering angle θtr. This can delay the phase of the steering force command value ft relative to the steering angle θs.

[0128] (2) The delay unit 52 may add the integral term calculated by integrating only the variable component of the target steering angle θtr to the proportional term of the target steering angle θtr, or may add the proportional term of the target steering angle θtr after limiting the integral term of the target steering angle θtr by a limit value corresponding to the target steering angle θtr. Thus, even when the target steering angle θtr is maintained at an angle other than zero in the steering hold state, the integral term of the target steering angle θtr can be prevented from continuously increasing, and the output of the delay unit 52 (i.e., the target steering angle θtrd after the phase is delayed) can be fixed to an angle corresponding to the target steering angle θtr.

[0129] (Third Embodiment)

[0130] As described above, the vehicle behavior responds faster to the steering operation immediately after the actual steering angle θt starts to change. Therefore, it is preferred that the phase of the steering force command value ft is delayed relative to the steering angle θs immediately after the actual steering angle θt starts to change, and that the phase is not delayed otherwise.

[0131] Therefore, the steering control unit 41 of the third embodiment delays the phase of the steering force command value ft relative to the steering angle θs when the steering angle θs is smaller than a predetermined value, and does not delay the phase of the steering force command value ft relative to the steering angle θs when the steering angle θs is greater than or equal to the predetermined value.

[0132] Fig. 8A 1 is a block diagram showing an example of the functional configuration of the steering control unit 41 of the third embodiment. The steering control unit 41 of the third embodiment further includes a gain setting unit 70, multipliers 71 and 73, a subtractor 72, and an adder 74. In addition, the delay unit 52 may be a phase lag filter (delay filter) or the delay unit 52 of the second embodiment.

[0133] The gain setting unit 70 sets a gain G corresponding to the steering angle θs. The gain G is a gain that is not zero when the steering angle θs is less than a predetermined value, and is zero when the steering angle θs is greater than or equal to a predetermined value.

[0134] For example, the gain setting unit 70 may set the gain G according to the target steering angle θtr set based on the steering angle θs. As described above, the target steering angle θtr is the product of the steering angle θs and the angle ratio Ra.

[0135] Figure 8B : is an explanatory diagram of an example of the gain G. The value of the gain G is "1" when the target steering angle θtr is less than θ1, and is "0" when the target steering angle θtr is greater than θ2. When the target steering angle θtr is greater than θ1 and less than θ2, the gain G decreases from "1" to "0" as the target steering angle θtr increases.

[0136] The multipliers 71 and 73 , the subtractor 72 , and the adder 74 calculate a weighted sum (G×θtrd+(1−G)×θtr) of the target steering angle θtrd and the target steering angle θtr whose phases are delayed by the delay unit 52 .

[0137] The steering angle control unit 53 calculates the steering force command value ft for making the actual steering angle θt coincide with the weighted sum (G×θtrd+(1-G)×θtr) based on the difference between the weighted sum (G×θtrd+(1-G)×θtr) and the actual steering angle θt.

[0138] Therefore, when the target steering angle θtr is equal to or greater than θ2, the weighted sum (G×θtrd+(1-G)×θtr) becomes the target steering angle θtr without phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0139] On the other hand, when the target steering angle θtr is smaller than θ2, the weighted sum (G×θtrd+(1-G)×θtr) includes the delayed component of the target steering angle θtrd, and thus the phase is delayed relative to the steering angle θs. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0140] Thus, the steering force command value ft can be generated so that the phase of the steering force command value ft is delayed relative to the steering angle θs in the period immediately after the steering angle θs starts to change from the neutral position and the phase is not delayed in the other periods.

[0141] Fig.9A This is a block diagram showing an example of the functional configuration of a first modified example of the steering control unit 41 according to the third embodiment.

[0142] The steering control unit 41 of the first modified example delays the phase of the steering force command value ft relative to the steering angle θs when the angular velocity of the steering angle θs is less than a predetermined value, and does not delay the phase of the steering force command value ft relative to the steering angle θs when the angular velocity of the steering angle θs is greater than or equal to the predetermined value.

[0143] Thus, the phase of the steering force command value ft can be delayed relative to the steering angle θs not only immediately after the steering angle θs starts changing from the neutral position but also immediately after the steering angle θs starts changing from the state where the steering is maintained at a position other than the neutral position.

[0144] The gain setting unit 70 sets the gain G corresponding to the angular velocity of the steering angle θs. For example, the gain setting unit 70 may set the gain G to be non-zero when the angular velocity of the steering angle θs is less than a predetermined value, and to be zero when the angular velocity of the steering angle θs is greater than a predetermined value.

[0145] For example, the gain setting unit 70 may set the gain G based on the steering angular velocity ω obtained by differentiating the target steering angle θtr.

[0146] The steered steering control unit 41 according to the first modified example includes a differentiator 75 that differentiates the target steered angle θtr to calculate the steered angular velocity ω.

[0147] The gain setting unit 70 sets a gain G corresponding to the steering angular velocity ω.

[0148] Fig. 9B: is an explanatory diagram of an example of the gain G. The value of the gain G is "1" when the steering angular velocity ω is equal to or less than ω1, and is "0" when the steering angular velocity ω is equal to or greater than ω2.

[0149] When the steering angular velocity ω is greater than ω1 and less than ω2, the value decreases from “1” to “0” as the steering angular velocity ω increases.

[0150] Therefore, when the steering angular velocity ω is equal to or greater than ω2, the value of the weighted sum (G×θtrd+(1-G)×θtr) becomes the target steering angle θtr, and there is no phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0151] On the other hand, when the steering angular velocity ω is less than ω2, the weighted sum (G×θtrd+(1-G)×θtr) includes a component of the target steering angle θtrd whose phase is delayed, and therefore the phase is delayed relative to the steering angle θs. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0152] Thus, the steering force command value ft can be generated so that the phase of the steering force command value ft is delayed relative to the steering angle θs after the steering angle θs starts to change from the state where the steering wheel 31a is stationary, and the phase is not delayed while the steering angle θs changes.

[0153] Fig. 10A This is a block diagram showing an example of the functional configuration of a second modified example of the steering control unit 41 according to the third embodiment.

[0154] The steering control unit 41 of the first modified example described above may delay the phase of the steering force command value ft with respect to the steering angle θs during the transition from the state where the steering angle θs is changing to the steering holding state where the steering wheel 31a is stationary, even if it is not the period immediately after the steering angle θs starts to change. This is because the angular velocity of the steering angle θs decreases during the transition to the steering holding state.

[0155] Therefore, the steering control unit 41 of the second variant delays the phase of the steering force command value ft relative to the steering angle θs when the angular acceleration of the steering angle θs is less than a specified value, and does not delay the phase of the steering force command value ft relative to the steering angle θs when the angular acceleration of the steering angle θs is greater than the specified value.

[0156] Thus, even if the angular velocity of the steering angle θs decreases during the transition to the steering holding state, the angular acceleration of the steering angle θs can be detected, and the phase delay of the steering force command value ft can be suppressed.

[0157] The gain setting unit 70 sets the gain G corresponding to the angular acceleration of the steering angle θs. For example, the gain setting unit 70 may set the gain G to be non-zero when the angular acceleration of the steering angle θs is less than a predetermined value, and to be zero when the angular acceleration of the steering angle θs is greater than a predetermined value.

[0158] For example, the gain setting unit 70 may set the gain G based on the steering angle acceleration α obtained by performing a second-order differentiation on the target steering angle θtr.

[0159] The steered steering control unit 41 of the second modified example includes a differentiator 76 that differentiates the steered steering angular velocity ω of the target steered angle θtr to calculate the steered steering angular acceleration α.

[0160] The gain setting unit 70 sets a gain G corresponding to the steering angular acceleration α. Fig. 10B 2 is an explanatory diagram of an example of the gain G. The value of the gain G is "1" when the steering angular acceleration α is equal to or less than α1, and is "0" when the steering angular acceleration α is equal to or greater than α2.

[0161] When the steering angular acceleration α is greater than α1 and less than α2, the value decreases from “1” to “0” as the steering angular acceleration α increases.

[0162] Therefore, when the steering angular acceleration α is equal to or greater than α2, the weighted sum (G×θtrd+(1-G)×θtr) becomes the target steering angle θtr without phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0163] On the other hand, when the steering angular acceleration α is less than α2, the weighted sum (G×θtrd+(1-G)×θtr) includes a component of the target steering angle θtrd whose phase is delayed, so the phase is delayed relative to the steering angle θs. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0164] Thus, the steering angle θs starts to change from the state where the steering wheel 31a is stationary. In the initial period when the angular acceleration is still small right after the steering angle θs starts to change, the phase of the steering force command value ft can be delayed relative to the steering angle θs.

[0165] Furthermore, during the transition from the state where the steering angle θs changes to the state where the steering wheel 31a is stationary and the steering is maintained, even if the angular velocity of the steering angle θs decreases, the angular acceleration of the steering angle θs can be detected, and the phase delay of the steering force command value ft can be suppressed.

[0166] Fig.11A This is a block diagram showing an example of the functional configuration of a third modified example of the steering control unit 41 of the third embodiment.

[0167] The steering control unit 41 of the third variant delays the phase of the steering force command value ft relative to the steering angle θs when the steering torque Ts applied to the steering wheel 31a is less than a specified value, and does not delay the phase of the steering force command value ft relative to the steering angle θs when the steering torque Ts is greater than the specified value.

[0168] The steerage control unit 41 of the third modified example achieves the same effects as those of the steerage control unit 41 of the second modified example.

[0169] The gain setting unit 70 sets a gain G corresponding to the steering torque Ts. Fig. 11B 2 is an explanatory diagram of an example of the gain G. The value of the gain G is "1" when the steering torque Ts is equal to or less than T1, and is "0" when the steering torque Ts is equal to or greater than T2.

[0170] When the steering torque Ts is larger than T1 and smaller than T2, the value decreases from "1" to "0" as the steering torque Ts increases.

[0171] Therefore, when the steering torque Ts is equal to or greater than T2, the value of the weighted sum (G×θtrd+(1-G)×θtr) becomes the target steering angle θtr without phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0172] On the other hand, when the steering torque Ts is less than T2, the weighted sum (G×θtrd+(1-G)×θtr) includes the delayed component of the target steering angle θtrd, so the phase is delayed relative to the steering angle θs. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0173] Fig. 12A This is a block diagram showing an example of the functional configuration of a fourth modified example of the steering control unit 41 of the third embodiment.

[0174] The steering control unit 41 of the fourth variant delays the phase of the steering force command value ft relative to the steering angle θs when the time change j of the steering torque Ts is less than a specified value, and does not delay the phase of the steering force command value ft relative to the steering angle θs when the time change j of the steering torque Ts is greater than a specified value.

[0175] The time variation j of the steering torque Ts may be replaced by the steering angle jump (steering angle jerk, steering angle impulse jump) of the steering angle θs.

[0176] Thus, the steering angle θs starts to change from the state where the steering wheel 31a is stationary. In the initial period when the steering angle jump is still small right after the steering angle θs starts to change, the phase of the steering force command value ft can be delayed relative to the steering angle θs.

[0177] Furthermore, during the transition from the state where the steering angle θs changes to the steering hold state where the steering wheel 31a is stationary, the phase delay of the steering force command value ft can be suppressed until the moment when the steering angle jump becomes small just before the transition to the steering hold state.

[0178] The steering control unit 41 according to the fourth modified example includes a differentiator 75 that differentiates the steering torque Ts to calculate a time change j of the steering torque Ts.

[0179] The gain setting unit 70 sets the gain G corresponding to the time change j. Fig. 12B : is an explanatory diagram of an example of the gain G. The value of the gain G is "1" when the time change j is less than or equal to j1, and is "0" when the time change j is greater than or equal to j2.

[0180] When the time change j is greater than j1 and less than j2, it decreases from "1" to "0" as the time change j increases.

[0181] Therefore, when the time change j is equal to or greater than j2, the value of the weighted sum (G×θtrd+(1-G)×θtr) becomes the target steering angle θtr without phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0182] On the other hand, when the time change j is less than j2, the weighted sum (G×θtrd+(1-G)×θtr) includes the component of the target steering angle θtrd whose phase is delayed, so the phase is delayed relative to the steering angle θs. Therefore, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0183] In addition, any multiple variations of the first to fourth variations may be combined. For example, when the values ​​of multiple variables of the steering angle velocity, steering angle acceleration, or steering angle jump of the steering angle θs are all less than the threshold value, the phase of the steering force command value ft may be delayed relative to the steering angle θs. The steering angle acceleration and steering angle jump of the steering angle θs may be replaced by the steering torque Ts or the time change j of the steering torque Ts.

[0184] (Effects of the Third Embodiment)

[0185] The steering control unit 41 delays the phase of the steering force command value ft relative to the steering angle θs when the steering angle θs, the steering angular velocity, the steering angular acceleration, or the steering angle jump of the steering angle θs, the steering torque Ts applied to the steering wheel 31a, or the time change j of the steering torque Ts is smaller than a prescribed value.

[0186] Thus, the phase of the steering force command value ft can be delayed relative to the steering angle θs in the period immediately after the steering angle θt starts to change when the vehicle behavior becomes more responsive to the steering operation, while the phase delay can be suppressed in the other periods.

[0187] (Fourth Embodiment)

[0188] The steered steering control unit 41 of the first embodiment described above delays the phase of the target steered angle θtr to thereby delay the phase of the steered force command value ft with respect to the steering angle θs.

[0189] Instead, the steerage control unit 41 of the fourth embodiment delays the phase of the steerage force command value outputted from the steerage angle control unit 53 to thereby delay the phase of the steerage force command value ft with respect to the steering angle θs.

[0190] This produces the same effects as those of the steering control unit 41 of the first embodiment.

[0191] Fig.13 It is a block diagram showing an example of the functional configuration of the steering control unit 41 according to the fourth embodiment.

[0192] The steer angle control unit 53 calculates a reference steer force command value ft0 for making the actual steer angle θt coincide with the target steer angle θtr based on the difference between the target steer angle θtr set by the steer angle setting unit 50 and the actual steer angle θt.

[0193] The delay unit 52 delays the phase of the reference steering force command value ft0 outputted from the steering angle control unit 53, and outputs the resultant as the steering force command value ft. The delay unit 52 may be, for example, a phase delay filter (delay filter).

[0194] Next, refer to Fig.14 An example of the steering method according to the fourth embodiment will be described.

[0195] The processing of steps S11 to S13 is Figure 5 The processing of steps S1 to S3 is the same.

[0196] In step S14 , the steer angle control unit 53 calculates a reference steer force command value ft0 for making the actual steer angle θt coincide with the target steer angle θtr based on the difference between the target steer angle θtr set by the steer angle setting unit 50 and the actual steer angle θt.

[0197] In step S15 , the delay unit 52 delays (retards) the phase of the reference steering force command value ft0 outputted from the steering angle control unit 53 , and outputs the phase-delayed steering force command value ft.

[0198] The processing of step S16 is Figure 5 The processing of step S7 is the same as that of step S7.

[0199] Fig.15 It is a block diagram showing an example of the functional configuration of a modified example of the steering control unit 41 according to the fourth embodiment.

[0200] The steering control unit 41 of the fourth embodiment is the same as the steering control unit 41 of the third embodiment. When the steering angle θs is less than a specified value, the phase of the steering force command value ft is delayed relative to the steering angle θs, and when the steering angle θs is greater than the specified value, the phase of the steering force command value ft is not delayed relative to the steering angle θs.

[0201] Therefore, the steering control unit 41 of the modified example includes a gain setting unit 70 , multipliers 71 and 73 , a subtractor 72 , and an adder 74 , similarly to the steering control unit 41 of the third embodiment.

[0202] The gain setting unit 70 sets the gain G corresponding to the steering angle θs similarly to the gain setting unit 70 of the third embodiment. The gain G is not zero when the steering angle θs is less than a predetermined value, but becomes zero when the steering angle θs is greater than or equal to a predetermined value.

[0203] The multipliers 71 and 73, the subtractor 72 and the adder 74 calculate a weighted sum (G×ft1+(1-G)×ft0) of the reference turning force command value ft0 and the turning force command value ft1 after the phase of the reference turning force command value ft0 is delayed by the delay unit 52 as the turning force command value ft.

[0204] Therefore, when the steering angle θs is equal to or greater than a predetermined value, the steering force command value ft becomes a reference steering force command value ft0 that does not include a phase delay. Therefore, there is no phase delay of the steering force command value ft relative to the steering angle θs.

[0205] On the other hand, when the steering angle θs is smaller than the predetermined value, the weighted sum (G×ft1+(1-G)×ft0) includes the component of the steering force command value ft1 whose phase is delayed. Therefore, similarly to the third embodiment, the phase of the steering force command value ft is delayed relative to the steering angle θs.

[0206] Furthermore, the gain setting unit 70 of the fourth embodiment may calculate gains corresponding to the steering angular velocity ω, the steering angular acceleration α, the steering torque Ts, and the time variation of the steering torque Ts, similarly to the gain setting unit 70 of the first to fourth modified examples of the third embodiment.

[0207] Therefore, the steering control unit 41 of the fourth embodiment may not delay the phase of the steering force command value ft relative to the steering angle θs when the steering angular velocity, steering angular acceleration, steering angle jump, steering torque Ts applied to the steering wheel 31a, or the time change j of the steering force Ts of the steering angle θs is greater than a specified value, but may delay the phase of the steering force command value ft when the steering angular velocity, steering angular acceleration, steering angle jump, steering torque Ts, or the time change j of the steering torque Ts is less than a specified value.

[0208] (Effects of the Fourth Embodiment)

[0209] The steerage control unit 41 may delay the phase of the steerage force command value ft with respect to the steering angle θs by delaying the phase of the steerage force command value ft calculated based on the difference between the actual steerage angle θt and the target steerage angle θtr.

[0210] This can suppress the vehicle behavior from responding too quickly to the steering force applied by the driver, thereby reducing the driver's discomfort.

[0211] All examples and terms of conditions recorded herein are intended to help readers understand the present invention and the concepts given by the inventor for the advancement of technology. They are intended to be educational terms and should be interpreted as not limited to the examples and conditions specifically recorded above, and the examples in this specification that represent the superiority and inferiority of the present invention. Although the embodiments of the present invention are described in detail, it should be understood that various changes, substitutions and modifications can be made to them without departing from the spirit and scope of the present invention.

[0212] Explanation of symbols

[0213] 11: controller; 12: reaction force actuator; 13: first drive circuit; 14: steering actuator; 15: second drive circuit; 16: torque sensor; 17: vehicle speed sensor; 19: steering angle sensor; 20: processor; 21: storage device; 31: steering unit; 31a: steering wheel; 31b: column shaft; 32: steering unit; 32a: pinion shaft; 32b: steering gear; 32c: rack; 32d: steering rack; 33: standby clutch Clutch; 34: Steering wheel; 34FL: Left front wheel; 34FR: Right front wheel; 35: Steering angle sensor; 40: Reaction force control unit; 41: Steering control unit; 50: Steering angle setting unit; 52: Delay unit; 53: Steering angle control unit; 60: Gain multiplication unit; 61: Delay element; 62, 64, 74: Adder; 63: Limiter; 65, 72: Subtractor; 70: Gain setting unit; 71, 73: Multiplier; 75, 76: Differentiator

Claims

1. A steering method for steering a steering wheel of a vehicle, characterized in that: Detect the steering angle of the steering wheel; Detecting the actual steering angle of the steering wheel, that is, the actual steering angle; Calculating the target steering angle of the steering wheel according to the detected steering angle, calculating a steering force command value for making the actual steering angle coincide with the target steering angle based on a difference between the actual steering angle and the target steering angle, The phase of the target steering angle is delayed by adding an integral term of the target steering angle calculated based on the detected steering angle to a proportional term of the target steering angle. By delaying the phase of the target steering angle calculated based on the detected steering angle, the phase of the steering force command value is delayed relative to the detected steering angle. A steering force for steering the steered wheel is generated based on the steering force command value whose phase is delayed.

2. The steering method according to claim 1, characterized in that: The integral term is calculated by integrating only the variation component of the target steering angle, or the integral term is limited by a limit value corresponding to the target steering angle.

3. A steering method for steering a steering wheel of a vehicle, characterized in that: Detect the steering angle of the steering wheel; Detecting the actual steering angle of the steering wheel, that is, the actual steering angle; Calculating the target steering angle of the steering wheel according to the detected steering angle, calculating a steering force command value for making the actual steering angle coincide with the target steering angle based on a difference between the actual steering angle and the target steering angle, When the detected steering angle, the steering angle velocity, the steering angle acceleration, or the steering angle jump of the steering angle, the steering force applied to the steering wheel, or the time change of the steering force is smaller than a predetermined value, the phase of the steering force command value is delayed relative to the detected steering angle, A steering force for steering the steered wheel is generated based on the steering force command value whose phase is delayed.

4. The steering method according to claim 3, characterized in that: By delaying the phase of the target steering angle calculated based on the detected steering angle, the phase of the steering force command value is delayed with respect to the detected steering angle.

5. The steering method according to claim 3, characterized in that: By delaying the phase of the steering force command value calculated based on the difference between the actual steering angle and the target steering angle, the phase of the steering force command value is delayed with respect to the detected steering angle.

6. The steering method according to any one of claims 3 to 5, characterized in that: Use a delay filter to delay the phase.

7. The steering method according to claim 4, characterized in that: The phase of the target steering angle is delayed by adding an integral term of the target steering angle calculated based on the detected steering angle to a proportional term of the target steering angle.

8. The steering method according to claim 7, characterized in that: The integral term is calculated by integrating only the variation component of the target steering angle, or the integral term is limited by a limit value corresponding to the target steering angle.

9. A steering device for steering a steering wheel of a vehicle, characterized in that: have: a first sensor that detects a steering angle of a steering wheel; A second sensor, which detects the actual steering angle of the steering wheel, that is, the actual steering angle; an actuator that generates a steering force for steering the steering wheel; a controller that calculates a target steering angle of the steering wheel based on the steering angle detected by the first sensor, calculates a steering force command value for making the actual steering angle consistent with the target steering angle based on a difference between the actual steering angle and the target steering angle, and has a delay unit that delays a phase of the steering force command value relative to the detected steering angle, and drives the actuator based on the steering force command value whose phase is delayed by the delay unit, The delay unit delays the phase of the target steering angle by adding an integral term of the target steering angle calculated based on the detected steering angle to a proportional term of the target steering angle, and delays the phase of the steering force command value relative to the detected steering angle by delaying the phase of the target steering angle calculated based on the detected steering angle.

10. A steering device for steering a steering wheel of a vehicle, characterized in that: have: a first sensor that detects a steering angle of a steering wheel; A second sensor, which detects an actual steering angle of the steering wheel, that is, an actual steering angle; an actuator that generates a steering force for steering the steering wheel; A controller, which calculates a target steering angle of the steering wheel based on the steering angle detected by the first sensor, calculates a steering force command value for making the actual steering angle consistent with the target steering angle based on a difference between the actual steering angle and the target steering angle, and has a delay unit for delaying the phase of the steering force command value relative to the detected steering angle when the detected steering angle, or the steering angular velocity, steering angular acceleration, or steering angle jump of the steering angle, the steering force applied to the steering wheel, or the time variation of the steering force is less than a specified value, and the controller drives the actuator based on the steering force command value after the phase is delayed by the delay unit.

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