JP2023095122A - Steering method and steering apparatus - Google Patents

Abstract

To reduce a feeling of physical disorder that a driver has as a response of vehicle behavior to steering operation is quick in a steering device that steers steering wheels with steering force based upon a difference between an actual steering angle and a target steering angle.SOLUTION: A steering method comprises: detecting the steering angle of a steering wheel (S1); detecting an actual steering angle which is the actual steering angle of steering wheels (S2); calculating a target steering angle of the steering wheels according to the detected steering angle (S3); calculating a steering force command value for letting the actual steering angle reach the target steering angle based upon a difference between the actual steering angle and target steering angle, and reducing a gain of the steering command value in a predetermined frequency band (S4, S5); and generating steering force for steering the steering wheels according to the steering force command value reduced in gain (S6).SELECTED DRAWING: Figure 6

Description

The present invention relates to a steering method and a steering device.

Patent Document 1 discloses a steering actuator that includes a steering member that steers a vehicle and a steering device that steers wheels, calculates a steering angle according to the steering angle, and calculates the steering angle based on the calculated steering angle. A steering angle control device for controlling the

JP 2019-43391 A

A target steering angle is set according to the steering angle of the steering wheel steered by the driver, and steering is performed based on the difference between the actual steering angle, which is the actual steering angle of the steered wheels, and the target steering angle. When the force is generated, the response of the vehicle behavior to the driver's steering operation becomes faster, so the driver may feel uncomfortable.
The present invention provides a steering device that steers steered wheels with a steering force based on a difference between an actual steering angle and a target steering angle, and provides a driver's steerage caused by a quick vehicle behavior response to a steering operation. The purpose is to reduce discomfort.

According to one aspect of the present invention, a steering method is provided for steering steerable wheels of a vehicle. In the steering method, the steering angle of the steering wheel is detected, the actual steering angle, which is the actual steering angle of the steered wheels, is detected, and the target steering angle of the steered wheels is determined according to the detected steering angle. Based on the difference between the actual turning angle and the target turning angle, a turning force command value for matching the actual turning angle with the target turning angle is calculated, and a turning force command value in a predetermined frequency band is calculated. The gain of the value is reduced, and a steering force for steering the steered wheels is generated according to the steering force command value with the reduced gain.

According to the present invention, in the steering device that steers the steered wheels with a steering force based on the difference between the actual steering angle and the target steering angle, the steering that occurs due to the quick response of the vehicle behavior to the steering operation. It is possible to reduce the discomfort of the person.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of an example of the steering apparatus of embodiment. 3 is a block diagram of a functional configuration example of a controller; FIG. (a) and (b) are explanatory diagrams of an example of vehicle behavior that occurs when the phase of the steering force command value is delayed with respect to the detected steering angle. It is a block diagram of an example of functional composition of a steering control part of a 1st embodiment. (a) and (b) are Bode diagrams showing an example of frequency response characteristics of a gain reduction unit. 4 is a flowchart of an example of a steering method according to the first embodiment; It is a block diagram of the functional structural example of the steering control part of a modification. It is a block diagram of an example of functional composition of a steering control part of a 2nd embodiment. It is a block diagram of an example of functional composition of a steering control part of a 3rd embodiment. It is a flow chart of an example of a steering method of a 3rd embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each drawing is schematic and may differ from the actual one. Further, the embodiments of the present invention shown below are examples of apparatuses and methods for embodying the technical idea of the present invention. are not specific to the following: Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

(First embodiment)
(composition)
FIG. 1 is a schematic configuration diagram of an example of a steering apparatus for a vehicle according to first to third embodiments. The steering device of the embodiment includes a steering unit 31 that receives a steering input from the driver, a steering unit 32 that steers left and right front wheels 34FL and 34FR, a backup clutch 33, and a controller 11.
This steering system employs a steer-by-wire (SBW) system in which the steering section 31 and the steering section 32 are mechanically separated when the backup clutch 33 is released. In the following description, the left and right front wheels 34FL and 34FR may be referred to as "steering wheels 34".

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

The steering wheel 31a of the steering unit 31 is rotated by receiving reaction torque from the reaction actuator 12 and steering torque input by the driver. In this specification, the reaction torque applied to the steering wheel by the actuator may be referred to as "steering reaction torque".
The column shaft 31b rotates integrally with the steering wheel 31a.

On the other hand, the steering gear 32b of the steered portion 32 meshes with the rack gear 32c, and steers the steered wheels 34 according to the rotation of the pinion shaft 32a. As the steering gear 32b, for example, a rack-and-pinion steering gear or the like may be employed.
Backup clutch 33 is provided between column shaft 31b and pinion shaft 32a. The backup clutch 33 mechanically disconnects the steering portion 31 and the steering portion 32 when in the disengaged state, and mechanically connects the steering portion 31 and the steering portion 32 when in the engaged state. The backup clutch 33 is normally in a disengaged state, such as when the vehicle is running or when the ignition switch is turned on. When the vehicle is turned off or when the ignition switch of the vehicle is turned off (for example, when the vehicle is parked), it is in the engaged state. Therefore, in the following description, the backup clutch 33 is in the released state, and the steering wheel 31a and the steered portion 32 are mechanically separated.

The torque sensor 16 detects steering torque Ts transmitted from the steering wheel 31a to the column shaft 31b.
The vehicle speed sensor 17 detects the wheel speed of the vehicle equipped with the steering device of the embodiment, and calculates the vehicle speed Vv based on the wheel speed.
The steering angle sensor 19 detects the column shaft rotation angle, that is, the steering angle θs (steering wheel angle) of the steering wheel 31a.
A steering angle sensor 35 detects an actual steering angle θt, which is the actual steering angle of the steered wheels 34 .

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

The storage device 21 may comprise a semiconductor storage device, a magnetic storage device and an optical storage device. The storage device 21 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory, and a RAM (Random Access Memory).
Note that the controller 11 may be realized by a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller 11 may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

FIG. 2 is a block diagram showing an example of the functional configuration of the controller 11. As shown in FIG. The controller 11 includes a reaction force control section 40 and a steering control section 41 . The functions of the reaction force control section 40 and the steering control section 41 may be realized by the processor 20 executing a computer program stored in the storage device 21 of the controller 11, for example.
The reaction force control unit 40 applies steering reaction force torque (rotational torque applied to the steering wheel 31a, hereinafter also referred to as reaction torque) to the steering wheel according to the steering angle θs detected by the steering angle sensor 19. A reaction force command value fs, which is a command value of , is calculated.

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.
The reaction force actuator 12 may be, for example, an electric motor. The reaction force actuator 12 has an output shaft arranged coaxially with the column shaft 31b.
The reaction force actuator 12 outputs 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. FIG. A steering reaction torque is generated in the steering wheel 31a by applying rotational torque.

The first drive circuit 13 generates a torque that matches the actual steering reaction force torque estimated from the drive current of the reaction force actuator 12 and the reaction force torque indicated by the reaction force command value fs output from the reaction force control unit 40. The command current output to the reaction force actuator 12 is controlled by feedback. Alternatively, the command current output to the reaction force actuator 12 may be controlled by current feedback that matches the drive current of the reaction force actuator 12 with the drive current corresponding to the reaction force command value fs.

The steering control unit 41 provides a steering torque command value for steering the steered wheels 34 based on the steering angle θs of the steering wheel 31a, the actual steering angle θt of the steered wheels 34, and the vehicle speed Vv. A steering force command value ft is calculated.
Specifically, the steering control unit 41 calculates a target steering angle θtr, which is a target value of the steering angle of the steered wheels 34, based on the steering angle θs.

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, according to at least the vehicle speed Vv. For example, when the vehicle speed Vv is low, the angle ratio Ra is set to a relatively large value to improve handling of the steering wheel 31a, and when the vehicle speed Vv is high, the angle ratio Ra is set to a relatively small value. You may improve steering stability.

The steering control unit 41 issues a steering force command for matching the actual steering angle θt with the target steering angle θtr based on the difference (θtr−θt) between the actual steering angle θt and the target steering angle θtr. Calculate the value ft. The steering force command value ft is calculated to increase as the difference (θtr−θt) between the actual steering angle θt and the target steering angle θtr increases. The steering force command value ft is calculated, for example, 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 is stored in advance as a steering force map, and based on the calculated (θtr-θt) The steering force command value ft may be calculated with reference to the steering force map.
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.
The steering actuator 14 may be, for example, an electric motor such as a brushless motor. An output shaft of the steering actuator 14 is connected to the rack gear 32c via a reduction gear.

The steering actuator 14 outputs a steering torque for steering the steered wheels 34 to the steering rack 32 d according to the command current output from the second drive circuit 15 .
The second drive circuit 15 provides a torque that matches the actual steering torque estimated from the drive current of the steering actuator 14 and the steering torque indicated by the steering force command value ft output from the steering control section 41 . The command current output to the steering actuator 14 is controlled by feedback. Alternatively, the command current output to the steering actuator 14 may be controlled by current feedback that matches the drive current of the steering actuator 14 and the drive current corresponding to the steering force command value ft.

Thus, if a steering force is generated that matches the actual steering angle θt 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 driver can The response of the vehicle behavior to the steering operation is quick, and the driver may feel uncomfortable.
When servo control is performed so that the target steering angle .theta.tr calculated from the steering angle .theta.s and the actual steering angle .theta.t coincide with each other, the conventional steering apparatus transmits the steering torque to the steered wheels through the connection of the shaft. This is because the phase delay of the steering angle θt with respect to the steering angle θs is smaller than that.

For example, when the driver unconsciously slightly moves the steering wheel 31a or when a slight correction steering is generated, the driver may not anticipate when steering input including a relatively high steering frequency component is input. A yaw motion that does not occur may occur and the driver may feel uncomfortable.
In the following description, a phenomenon in which yaw motion unexpected by the driver occurs due to steering input including a relatively high steering frequency component is referred to as "picking".

Such jerking can be reduced by delaying the phase of the steering force command value ft with respect to the steering angle θs. However, if the phase of the steering force command value ft with respect to the steering angle θs is always delayed, the actual steering angle θt still increases after the driver stops rotating the steering wheel 31a to hold the steering. may occur.
In the following description, the phenomenon in which the actual turning angle θt still increases after the rotation of the steering wheel 31a stops and the steering wheel is maintained is referred to as "entanglement".

3(a) and 3(b) are explanatory diagrams of entrainment. The solid line in FIG. 3(a) indicates the target steering angle .theta.tr, and the dashed line indicates the actual steering angle .theta.t. The dashed line in FIG. 3(b) indicates the yaw rate expected by the driver, and the solid line indicates the actual yaw rate of the vehicle.
When the driver starts steering at time t0, the target steering angle θtr increases. By delaying the phase of the steering force command value ft with respect to the steering angle, the actual steering angle θt changes with a delay from the target steering angle θtr.

Please refer to FIG. At time t1, when the yaw rate of the vehicle reaches the yaw rate desired by the driver, the driver stops turning the steering wheel 31a. Therefore, as indicated by the solid line in FIG. 3A, the increase in the target steering angle θtr stops and the steering is held. However, as shown by the dashed line in FIG. 3(a), the actual steering angle θt continues to increase until time t2, so the yaw rate becomes higher than expected by the driver. Therefore, a steering-back operation (correction rudder) occurs as indicated by the solid line in FIG. 3(a).

Thus, if the phase of the steering force command value ft with respect to the steering angle θs is always delayed, a new problem of entrainment may occur.
Therefore, the steering control unit 41 of the embodiment reduces the picking by reducing the gain of the steering force command value ft only in a predetermined frequency band to delay the phase.
The steering frequency band of the steering input that causes the jerking is higher than the steering frequency band when the driver consciously steers the vehicle. For example, the former is about 3 Hz to 4 Hz, while the latter is about 1 Hz.

Therefore, by reducing the gain of the steering force command value ft only in a predetermined frequency band and delaying the phase, when steering including a relatively high steering frequency component that causes jerking is input. Since changes in the steering angle can be suppressed, occurrence of yaw motion unexpected by the driver can be suppressed. This can reduce picking.
On the other hand, in the steering frequency band of the steering input consciously performed by the driver, it is possible to avoid the decrease in the gain of the steering force command value ft and the phase delay. delay can be suppressed. This can suppress the occurrence of entanglement.

The steering control unit 41 will be further described below.
FIG. 4 is a block diagram of an example of the functional configuration of the steering control section 41 of the first embodiment. The steering control section 41 includes a steering angle setting section 50 , a gain reduction section 53 , an adder 54 and a steering angle control section 55 .
The steering angle setting unit 50 calculates the target steering angle θtr1 according to 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 θtr1.
The turning angle setting unit 50 may dynamically change the angle ratio Ra. For example, the turning angle setting unit 50 may change the angle ratio Ra according to at least the vehicle speed Vv.

For example, when the vehicle speed Vv is low, the angle ratio Ra is set to a relatively large value to improve handling of the steering wheel 31a, and when the vehicle speed Vv is high, the angle ratio Ra is set to a relatively small value. You may improve steering stability.
Alternatively, the target steering angle θtr1 for the steering angle θs is stored in advance as a steering angle map, and the target steering angle θtr1 is calculated by referring to the steering angle map based on the detected actual steering angle θs. good too. Further, by storing a plurality of turning angle maps according to the vehicle speed Vv, the relationship between the steering angle θs and the target turning angle θtr1 may be changed according to the vehicle speed Vv.

The gain reduction unit 53 reduces the gain in a predetermined frequency band of the target turning angle θtr1. That is, the predetermined frequency component of the target turning angle θtr1 is attenuated. The gain reduction unit 53 outputs to the adder 54 the target steering angle component θtr2 obtained by reducing the gain of the target steering angle θtr1 in the predetermined frequency band.
5A and 5B are Bode diagrams showing an example of the frequency response characteristic of the gain reduction section 53. FIG. For example, the gain reduction unit 53 attenuates the gain of the target steering angle θtr1 in the predetermined frequency band 60. FIG.

The predetermined frequency band 60 is a frequency band in which the null frequency, the lower limit frequency, and the upper limit frequency at which attenuation is maximized are f0, f1, and f2 [Hz], respectively. For example, the null frequency f0 may be set to a frequency within a predetermined range, which is the steering frequency of the steering input that causes jerking. Further, for example, the width of the predetermined frequency band 60 may be set so that the predetermined frequency band 60 does not include relatively low frequencies in the steering frequency band when the driver consciously steers the vehicle.
The gain reduction unit 53 gradually decreases the gain of the target steering angle θtr1 from the lower limit frequency f1 to the null frequency f0, and gradually increases the gain of the target steering angle θtr1 from the null frequency f0 to the upper limit frequency f2.
For example, the gain reduction section 53 may include a bandstop filter, or may include a notch filter with a narrow stopband, for example.

Please refer to FIG. The adder 54 adds the target steering angle θtr1 and the target steering angle component θtr2 whose gain is reduced in the predetermined frequency band by the gain reduction unit 53, and the sum of these is the target steering angle θtr=θtr2+θtr1. Output to the angle control unit 55 . Since the target steering angle θtr includes the target steering angle component θtr2, the gain of the target steering angle θtr in the predetermined frequency band is also reduced.

The turning angle control unit 55 matches the actual turning angle θt with the target turning angle θtr based on the difference between the target turning angle θtr whose gain is reduced in the predetermined frequency band and the actual turning angle θt. , the steering force command value ft is calculated.
In this way, the steering control unit 41 reduces the gain of the target steering angle θtr in the predetermined frequency band, thereby reducing the gain of the steering force command value ft calculated by the steering angle control unit 55 in the predetermined frequency band. to reduce

As a result, even if a steering frequency component of about a predetermined frequency band is input when the driver slightly moves the steering wheel 31a without being conscious of it, or when a minute correction steering is generated, the steering in this frequency band is detected. Since the gain of the force command value ft is reduced, yaw motion can be suppressed. This can reduce the occurrence of flickering.
In particular, even if the yaw resonance frequency of the vehicle increases as the vehicle speed Vv decreases and approaches the frequency (predetermined frequency band 60) of the steering frequency component included in the driver's unconscious steering input or minute steering correction. , the resonance of the vehicle due to these steering inputs can be suppressed, and the occurrence of jerking can be effectively reduced. Therefore, for example, the null frequency f0 of the predetermined frequency band 60 may be set to the yaw resonance frequency in a specific vehicle speed range. For example, the yaw resonance frequency may be set when the vehicle speed Vv is 30 km/h.

Further, as shown in FIG. 5B, in frequency bands other than the predetermined frequency band 60, the phase delay due to the gain reduction section 53 is small. Therefore, since the phase delay with respect to the steering at the steering frequency when the driver consciously steers the vehicle is small, the entrainment described with reference to FIGS. 3A and 3B can be prevented. can be reduced.

(motion)
Next, an example of the steering method of the first embodiment will be described with reference to FIG.
In step S1, the steering angle sensor 19 detects the steering angle θs of the steering wheel 31a.
In step S<b>2 , the turning angle sensor 35 detects the actual turning angle θt of the steered wheels 34 .
In step S3, the steering angle setting unit 50 calculates the target steering angle θtr1 according to the steering angle θs.

In step S4, the gain reduction unit 53 reduces the gain of the target steering angle θtr1 in the predetermined frequency band to obtain the target steering angle θtr.
In step S5, the steering angle control unit 55 calculates a steering force command value ft based on the difference between the target steering angle θtr with reduced gain in the predetermined frequency band and the actual steering angle θt.
In step S6, the second drive circuit 15 drives the steering actuator 14 based on the steering force command value ft. Processing then ends.

(Modification)
FIG. 7 is a block diagram of a functional configuration example of the steering control section 41 of the modification. The yaw resonance frequency of the vehicle increases as the vehicle speed Vv decreases. Therefore, when the vehicle speed Vv is in the low speed range, the yaw resonance frequency becomes close to the frequency (predetermined frequency band 60) of the steering frequency component included in the slight movement of the steering wheel 31a that the driver is not aware of or in the slight steering correction.
Therefore, the steering control unit 41 of the modified example reduces the gain of the steering force command value ft in the predetermined frequency band only when the vehicle speed Vv is in the low speed range.

The steering control unit 41 of the modified example has a configuration similar to that of the steering control unit 41 shown in FIG. 4 . Identical or similar components are therefore denoted with the same reference numerals. The steering controller 41 includes a phase compensation controller 56 , vehicle speed sensitive gain multipliers 57 a and 57 b , and an adder 58 .
The phase compensation control unit 56 calculates a delay compensation turning angle component θtr3 for compensating for the phase lag that occurs from the steering wheel 31a to the steered wheels 34, based on the linear model of the vehicle.

Vehicle speed sensitive gain multipliers 57a and 57b multiply the delay compensation turning angle component θtr3 and the target turning angle component θtr2 by vehicle speed sensitive gains Kv1 and Kv2 corresponding to the vehicle speed Vv, respectively.
The vehicle speed sensitive gain Kv1 is a vehicle speed sensitive gain that is "0" in the low speed range and "1" in the high speed range. For example, the vehicle speed sensitive gain Kv1 becomes "0" when the vehicle speed Vv is 10 km/h or less, becomes "1" when the vehicle speed Vv is 20 km/h or more, and changes from "0" when the vehicle speed Vv increases from 10 km/h to 20 km/h. May be incremented to "1".

The vehicle speed sensitive gain Kv2 is a vehicle speed sensitive gain that is "1" in the low speed range and "0" in the high speed range. For example, the vehicle speed sensitive gain Kv2 becomes "1" when the vehicle speed Vv is 30 km/h or less, becomes "0" when the vehicle speed Vv is 40 km/h or more, and changes from "1" when the vehicle speed Vv increases from 30 km/h to 40 km/h. May be reduced to "0".
The adders 54 and 58 output the sum obtained by adding the outputs of the vehicle speed sensitive gain multipliers 57a and 57b to the target turning angle θtr1 to the turning angle control unit 55 as the target turning angle θtr=θtr1+Kv1×θtr3+Kv2×θtr2. do.

(Second embodiment)
FIG. 8 is a block diagram of a functional configuration example of the steering control section 41 of the second embodiment. The steering control unit 41 of the second embodiment sets a predetermined frequency band for reducing the gain of the steering force command value ft according to the vehicle speed Vv.
A steering control unit 41 of the second embodiment has a configuration similar to that of the steering control unit 41 of the first embodiment shown in FIG. Identical or similar components are therefore denoted with the same reference numerals.

A gain reduction unit 53 of the second embodiment sets a predetermined frequency band for reducing the gain of the target turning angle θtr1 according to the vehicle speed Vv. For example, a higher predetermined frequency band is set when the vehicle speed Vv is lower than when the vehicle speed Vv is high.
For example, the gain reduction section 53 of the second embodiment may estimate the yaw resonance frequency according to the vehicle speed Vv. The gain reduction unit 53 of the second embodiment may set the predetermined frequency band 60 so that the null frequency f0 in FIGS. 5A and 5B becomes the yaw resonance frequency.

For example, if the gain reduction unit 53 includes a notch filter, the notch filter may be set so that the center frequency is the yaw resonance frequency. For example, the gain reduction unit 53 may set a predetermined frequency band according to the vehicle speed Vv by setting tap coefficients of a notch filter implemented by a digital filter according to the vehicle speed Vv.

(Third Embodiment)
The steering control unit 41 of the first and second embodiments described above delays the phase of the steering force command value ft in a predetermined frequency band by reducing the gain of the target steering angle θtr.
Instead of this, the steering control unit 41 of the fourth embodiment reduces the gain of the steering force command value itself output by the steering angle control unit 55, so that the steering force command value ft in the predetermined frequency band Reduce gain. As a result, the same effects as those of the steering control section 41 of the first embodiment and the second embodiment are obtained.

FIG. 9 is a block diagram of a functional configuration example of the steering control section 41 of the third embodiment.
The turning angle control unit 55 matches the actual turning angle θt with the target turning angle θtr based on the difference between the target turning angle θtr1 set by the turning angle setting unit 50 and the actual turning angle θt. , the steering force command value ft1 is calculated.

The gain reduction unit 53 reduces the gain of the steering force command value ft1 in a predetermined frequency band. That is, the predetermined frequency component of the steering force command value ft1 is attenuated. The gain reduction unit 53 outputs to the adder 54 a steering force command value component ft2 obtained by reducing the gain of the steering force command value ft1 in the predetermined frequency band.
The adder 54 adds the steering force command value ft1 and the steering force command value component ft2 whose gain is reduced in the predetermined frequency band by the gain reduction section 53, and the sum of these is the steering force command value ft=ft2+ft1. output as

FIG. 10 is a flowchart of an example of a steering method according to the third embodiment.
The processing of steps S11 to S13 is the same as the processing of steps S1 to S3 in FIG.
In step S14, the steering angle control unit 55 calculates a steering force command value ft1 based on the difference between the target steering angle θtr1 and the actual steering angle θt.
In step S15, the gain reduction unit 53 reduces the gain of the steering force command value ft1 in the predetermined frequency band to obtain the steering force command value ft.
In step S16, the second drive circuit 15 drives the steering actuator 14 based on the steering force command value ft with reduced gain in the predetermined frequency band. Processing then ends.

(Effect of Embodiment)
(1) The steering angle sensor 19 detects the steering angle of the steering wheel 31a. The steering angle sensor 35 detects the actual steering angle, which is the actual steering angle of the steered wheels. The controller 11 calculates a target steering angle of the steered wheels according to the detected steering angle, and adjusts the actual steering angle to the target steering angle based on the difference between the actual steering angle and the target steering angle. A steering force command value for matching is calculated, and the gain of the steering force command value in a predetermined frequency band is reduced. The second drive circuit 15 and the steering actuator 14 generate a steering force for steering the steered wheels 34 according to the steering force command value with the reduced gain.

For example, the controller 11 may reduce the gain of the turning force command value in a predetermined frequency band by reducing the gain of the target turning angle. Further, for example, the controller 11 reduces the gain of the turning force command value in a predetermined frequency band by reducing the gain of the turning force command value calculated based on the difference between the actual turning angle and the target turning angle. may
As a result, even if steering including a steering frequency component in a predetermined frequency band is input when the driver slightly moves the steering wheel 31a unconsciously or when a minute correction steering is generated, Since the gain of the steering force command value is reduced, the yaw motion can be suppressed. This can reduce the occurrence of flickering.
On the other hand, in the steering frequency band of the steering input consciously performed by the driver, it is possible to avoid the decrease in the gain gain and the phase delay of the steering force command value. delay can be suppressed. This can suppress the occurrence of entanglement.

(2) The predetermined frequency band may be set to a frequency band near the yaw resonance frequency of the vehicle.
As a result, even if the yaw resonance frequency becomes close to the frequency of the steering frequency component included in steering input that the driver is not conscious of or due to minute steering correction, it is possible to suppress the vehicle from resonating due to such steering input. can effectively reduce the occurrence of

(3) The controller 11 gradually decreases the gain of the steering force command value from the lower limit frequency of the predetermined frequency band to the null frequency, and gradually increases the gain of the steering force command value from the null frequency to the upper limit frequency of the frequency band. You may let
For example, the controller 11 may reduce the gain of the steering force command value in a predetermined frequency band using a bandstop filter.
As a result, it is possible to reduce the gain of the steering force command value in the predetermined frequency band and to avoid gain reduction and phase delay in frequency bands other than the predetermined frequency band.

(4) The vehicle speed sensor 17 may detect the vehicle speed. The controller 11 may set a higher predetermined frequency band when the vehicle speed is low than when the vehicle speed is high.
As a result, the yaw resonance frequency of the vehicle increases as the vehicle speed Vv decreases, and even if the yaw resonance frequency approaches the frequency of the steering frequency component included in the steering input that the driver is not aware of or in the minute steering correction. , the resonance of the vehicle due to these steering inputs can be suppressed, and the occurrence of jerking can be effectively reduced.

DESCRIPTION OF SYMBOLS 11... Controller, 12... Reaction 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 gear 32d Steering rack 33 Backup clutch 34 Steering wheel 34FL Left and right front wheels 34FR Left and right front wheels 35 Turning angle sensor 40 Reaction force control unit 41 Turning control unit 50 Turning angle setting unit 51 Coefficient multiplying unit , 52... Subtractor 53... Gain reduction unit 54, 58... Adder 55... Turning angle control unit 56... Phase compensation control unit 57a, 57b... Vehicle speed sensitive gain multiplier 58... Adder

Claims (8)

A steering method for steering a steerable wheel of a vehicle,
detecting the steering angle of the steering wheel,
detecting an actual steering angle, which is the actual steering angle of the steerable wheels;
calculating a target steering angle of the steerable wheels according to the detected steering angle;
calculating a steering force command value for matching the actual steering angle with the target steering angle based on the difference between the actual steering angle and the target steering angle;
reducing the gain of the steering force command value in a predetermined frequency band,
generating a steering force for steering the steered wheels according to the steering force command value with the reduced gain;
A steering method characterized by: 2. The steering method according to claim 1, wherein the gain of the steering force command value in the predetermined frequency band is reduced by reducing the gain of the target steering angle. Reducing the gain of the turning force command value in the predetermined frequency band by reducing the gain of the turning force command value calculated based on the difference between the actual turning angle and the target turning angle. The steering method according to claim 1, characterized by: The steering method according to any one of claims 1 to 3, wherein the predetermined frequency band is a frequency band near a yaw resonance frequency of the vehicle. Gradually decreasing the gain of the steering force command value from the lower limit frequency of the predetermined frequency band to the null frequency, and gradually increasing the gain of the steering force command value from the null frequency to the upper limit frequency of the frequency band. The steering method according to any one of claims 1 to 4, characterized by: 6. The steering method according to claim 5, wherein a bandstop filter is used to reduce the gain of said steering force command value in said predetermined frequency band. detecting the vehicle speed of the vehicle;
setting the predetermined frequency band higher when the vehicle speed is lower than when the vehicle speed is high;
The steering method according to any one of claims 1 to 6, characterized in that: A steering device for steering a steerable wheel of a vehicle,
a first sensor that detects the steering angle of the steering wheel;
a second sensor that detects an actual steering angle that is the actual steering angle of the steerable wheels;
an actuator that generates a steering force for steering the steerable wheels;
A target steering angle of the steered wheels is calculated according to the steering angle detected by the first sensor, and the actual steering angle is calculated based on a difference between the actual steering angle and the target steering angle. A steering force command value for matching with the target steering angle is calculated, and a gain reduction means is provided for reducing a gain of the steering force command value in a predetermined frequency band, and the steering with the reduced gain. a controller that drives the actuator according to the force command value;
A steering device comprising:

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