JP2013010479A - Vehicular steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular steering system capable of suppressing transmission of vibrations of a steering wheel to a steering member when a vehicle is driving on a pebbled road or the like.SOLUTION: A transmission ratio variable system 7 has a differential mechanism 13, which couples a first shaft 11 and a second shaft 12 so that differential rotation can be carried out, and a transmission ratio changing motor 14, which drives the differential mechanism 13. The transmission ratio changing motor 14 is subjected to feedback control so that an actual act angle θact calculated by an actual act angle calculating unit 76 is equal to a target act angle θact* calculated by a target act angle calculating unit 71. If it is determined by a disturbance determination unit 77 that disturbance has been input to the second shaft 12, a proportional gain Kused in feedback control of a transmission ratio changing motor 14 is reduced blow a normal one.

Description

  The present invention relates to a vehicle steering apparatus.

  2. Description of the Related Art A vehicle steering apparatus that includes a transmission ratio variable device that changes a ratio of a steered wheel turning angle to a steering angle of a steering member is known. A transmission ratio variable device includes: a differential mechanism that differentially connects a first shaft coupled to a steering member and a second shaft coupled to a steering mechanism; a transmission ratio changing motor that drives the differential mechanism; including. The transmission ratio variable device adds the rotation angle (act angle) of the second shaft based on the motor drive to the rotation angle of the first shaft based on the operation of the steering member, whereby the rotation angle of the first shaft (to the steering angle). The ratio of the rotation angle (corresponding to the turning angle) of the second shaft to the corresponding) is varied.

  The transmission ratio changing motor is controlled by a motor control device. For example, the motor control device calculates the target act angle according to the vehicle speed, the steering angle, etc., and transmits the actual act angle calculated from the actual rotation angle of the transmission ratio changing motor so as to be equal to the target act angle. Feedback control of the ratio changing motor.

JP 2009-51491 A JP 2003-291840 JP

In the above-described conventional vehicle steering apparatus, on a rough road such as a gravel road, the vibration of the steered wheels is transmitted to a steering member such as a steering wheel, so that the driver's steering feeling deteriorates. Further, when the vibration of the steered wheels is transmitted to the steering member in this way, the target act angle varies due to the variation of the steering angle, and the transmission ratio changing motor may be driven alternately in the forward and reverse directions. is there.
An object of the present invention is to provide a vehicle steering apparatus that can suppress transmission of vibrations of steered wheels to a steering member when the vehicle is traveling on a gravel road or the like.

  In order to achieve the above object, the invention according to claim 1 includes a first shaft (11) coupled to the steering member (2) and a second shaft (12) coupled to the steering mechanism (4). A differential mechanism (13) for connecting the rotation transmission ratio between the two shafts so that the transmission ratio can be changed, and for changing the transmission ratio for changing the rotation transmission ratio between the two shafts by driving the differential mechanism. Whether a disturbance is input to the second shaft via the motor (14), motor control means (71 to 76, 81, 82) for controlling the transmission ratio changing motor, and the steering mechanism. The disturbance input to the second shaft is transmitted to the first shaft when it is determined that the disturbance is input to the second shaft by the disturbance determining means (77) for determining and the disturbance determining means. In order to prevent Changing the control mode by the motor control means includes a control mode change means (78,71), a steering apparatus for a vehicle. In addition, although the alphanumeric character in parentheses represents a corresponding component in an embodiment described later, of course, the scope of the present invention is not limited to the embodiment. The same applies hereinafter.

According to the present invention, when the disturbance determining means determines that a disturbance is input to the second shaft, the motor is configured to suppress the disturbance input to the second shaft from being transmitted to the first shaft. The control mode of the control means is changed. Thereby, when the vehicle is traveling on a rough road such as a gravel road, it is possible to suppress the vibration of the steered wheels from being transmitted to the steering member.
The invention according to claim 2 includes rotation angle detection means (22) for detecting the rotation angle of the transmission ratio changing motor, wherein the motor control means is obtained from the rotation angle detected by the rotation angle detection means. The transmission ratio changing motor is feedback-controlled so that a feedback value (θact) is equal to a target value (θact ^* ) for controlling the rotation angle of the transmission ratio changing motor, The control mode changing means includes means (78) for reducing a control gain of feedback control in the motor control means when it is determined by the disturbance detection means that a disturbance is input to the second shaft. The vehicle steering apparatus according to Item 1.

  In this configuration, when a disturbance is input to the second shaft, the control gain of feedback control in the motor control unit is reduced. Thereby, since the responsiveness of the feedback control in the motor control means is lowered, it is possible to suppress the generation of torque from the transmission ratio changing motor for preventing the change in the rotation angle of the second shaft. As a result, the vibration of the second shaft is absorbed by the differential mechanism, and the vibration of the second shaft is hardly transmitted to the first shaft. Thereby, when the vehicle is traveling on a gravel road or the like, it is possible to suppress the vibration of the steered wheels from being transmitted to the steering member.

The invention according to claim 3 includes rotation angle detection means (22) for detecting the rotation angle of the transmission ratio changing motor, wherein the motor control means is obtained from the rotation angle detected by the rotation angle detection means. The transmission ratio changing motor is feedback-controlled so that a feedback value (θact) is equal to a target value (θact ^* ) for controlling the rotation angle of the transmission ratio changing motor, 2. The vehicle steering according to claim 1, wherein the control mode changing unit includes a unit that suppresses a change in the target value when it is determined by the disturbance detection unit that a disturbance is input to the second shaft. Device.

According to this configuration, since the change of the target value is suppressed at the time of disturbance input, it is possible to prevent the transmission ratio changing motor from being driven alternately in the forward and reverse directions at the time of disturbance input.
The invention according to claim 4 includes torque detection means for detecting a steering torque, and the disturbance detection means is configured such that the output signal of the torque detection means includes a frequency component higher than a predetermined frequency. The vehicle steering apparatus according to any one of claims 1 to 3, wherein the vehicle steering apparatus is configured to determine that a disturbance is input to the second shaft.

It is a mimetic diagram showing a schematic structure of a steering device for vehicles concerning one embodiment of this invention. It is a longitudinal cross-sectional view which shows the structural example of a transmission ratio variable apparatus. It is a block diagram which shows schematic structure of ECU for transmission ratio variable apparatuses. It is a block diagram which shows schematic structure of the other example of ECU for transmission ratio variable apparatuses.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus as a vehicle steering apparatus according to an embodiment of the present invention.
The electric power steering apparatus 1 includes a steering wheel 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers the steered wheels 3L and 3R in conjunction with the rotation of the steering wheel 2, and a driver. And a steering assist device 5 for assisting the steering.

The steering wheel 2 and the steering mechanism 4 are connected via a steering shaft 6, a transmission ratio variable device 7, a universal joint 8, an intermediate shaft 9, and a universal joint 10.
The steering shaft 6 includes a first shaft 11 and a second shaft 12 arranged coaxially with the first shaft 11. A steering wheel 2 is connected to one end of the first shaft 11 so as to be able to rotate together. The other end of the first shaft 11 and one end of the second shaft 12 are connected via a transmission ratio variable device 7 so as to be differentially rotatable. The other end of the second shaft 12 is connected to the intermediate shaft 9 via the universal joint 5.

  A rudder angle sensor 21 for detecting a steering angle θh, which is the rotation angle of the first shaft 11, is disposed around the first shaft 11. In this embodiment, the rudder angle sensor 21 detects the amount of rotation (rotation angle) of the first shaft 11 in both forward and reverse directions from the neutral position of the first shaft 11, and rotates rightward from the neutral position. The amount is output as a positive value, for example, and the amount of rotation from the neutral position to the left is output as a negative value, for example.

  The transmission ratio variable device 7 is for changing the ratio of the rotation angle (corresponding to the turning angle) of the second shaft 12 to the rotation angle (corresponding to the steering angle θh) of the first shaft 11. The transmission ratio variable device 7 includes a differential mechanism 13 that connects the first shaft 11 and the second shaft 12 so as to be differentially rotatable, and a transmission ratio changing motor 14 that drives the differential mechanism 13. The transmission ratio changing motor 14 is a three-phase brushless motor. In the vicinity of the transmission ratio changing motor 14, a rotation angle sensor 22 made of, for example, a resolver for detecting the rotation angle θd of the rotor of the transmission ratio changing motor 14 is disposed.

  The steering mechanism 4 includes a pinion shaft 15 connected to the universal joint 10, a rack shaft 16 having a rack 16 a that meshes with a pinion 15 a at the tip of the pinion shaft 15, and tie rods 17 </ b> L and 17 </ b> R at a pair of ends of the rack shaft 16. And knuckle arms 18L and 18R connected to each other. The rack shaft 16 extends in the left-right direction of the vehicle. A torque sensor 23 for detecting the steering torque Th is disposed around the pinion shaft 15.

  When the steering wheel 2 is steered (rotated), this rotation is transmitted to the steering mechanism 4 via the steering shaft 6 or the like. In the steering mechanism 4, the rotation of the pinion 15a is converted into the movement of the rack shaft 16 in the axial direction, and the corresponding knuckle arms 18L and 18R rotate through the tie rods 17L and 17R, respectively. Thereby, the corresponding steered wheels 3L and 3R connected to the knuckle arms 18L and 18R are respectively steered.

  The steering assist device 5 includes a steering assist motor 19 disposed coaxially with the rack shaft 16, and a ball screw mechanism (converting the output torque of the steering assist motor 19 into a motion in the rack axis direction and transmitting it to the rack shaft 16 ( (Not shown). The steering assist motor 19 is a three-phase brushless motor. A rotation angle sensor 24 made of, for example, a resolver for detecting the rotation angle θs of the rotor of the steering assist motor 19 is disposed in the vicinity of the steering assist motor 19. When the steering assist motor 19 is driven to rotate, this rotation is converted into an axial movement of the rack shaft 16 by the ball screw mechanism. Thereby, the steered wheels 3L and 3R are steered.

The electric power steering device 1 further includes a vehicle speed sensor 25 for detecting the vehicle speed V, a steering assist device ECU (ECU: electronic control unit) 31 for controlling the steering assist motor 19, and a transmission ratio change. And a transmission ratio variable device ECU 32 for controlling the motor 14.
The steering assist device ECU 31 receives the vehicle speed V detected by the vehicle speed sensor 25, the steering torque Th detected by the torque sensor 23, and the rotation angle θs of the rotor of the steering assist motor 19 detected by the rotation angle sensor 24. Is done. For example, the steering assist device ECU 31 determines the target assist amount using a map in which the relationship between the steering torque and the target assist amount is stored for each vehicle speed, and the assist force generated by the steering assist motor 19 becomes the target assist amount. The steering assist motor 19 is controlled to be equal.

  The transmission ratio variable device ECU 32 includes a vehicle speed V detected by the vehicle speed sensor 25, a steering angle θh detected by the steering angle sensor 21, and a rotation angle of the rotor of the transmission ratio changing motor 14 detected by the rotation angle sensor 22. θd and the output signal of the torque sensor 23 are input. The transmission ratio variable device ECU 32 controls the transmission ratio changing motor 14 based on the vehicle speed V, the steering angle θh, the rotation angle θd, and the output signal of the torque sensor 23 input to the transmission ratio variable device ECU 32.

FIG. 2 is a longitudinal sectional view showing a configuration example of the transmission ratio variable device 7.
The differential mechanism 13 includes a first sun gear 41 connected to the first shaft 11 so as to be able to rotate along with the first shaft 11, a second sun gear 42 connected so as to be able to rotate along with the second shaft 12, and first and second sun gears 41, 42, and a carrier 44 that holds the planetary gear 43 so as to be capable of rotating about its axis and revolving around the axes of the first and second sun gears 41 and 42.

The carrier 44 has a cylindrical shape whose upper and lower open ends are closed. A through hole is formed in the center of the upper surface wall of the carrier 44, and the lower end portion of the first shaft 11 passes through the through hole so as to be rotatable. Further, a through hole is formed in the center of the lower wall of the carrier 44, and the upper end portion of the second shaft 12 passes through the through hole so as to be rotatable.
The first sun gear 41 is connected to the lower end portion of the first shaft 11, and the second sun gear 42 is connected to the upper end portion of the second shaft 12. A plurality (two in this embodiment) of planetary gears 43 are arranged at equal intervals in the circumferential direction of the steering shaft 6. Each planetary gear 43 meshes with both the first and second sun gears 41 and 42.

  The transmission ratio changing motor 14 is for rotating the carrier 43 around the axis of the steering shaft 6. The transmission ratio changing motor 14 is arranged coaxially with the steering shaft 6. The transmission ratio changing motor 14 includes a rotor 51 connected to the carrier 43 so as to be able to rotate along with the carrier 43, and a stator 52 that surrounds the rotor 51 and is fixed to the housing 50.

  When the first shaft 11 is rotated by the operation of the steering wheel 2, the second shaft 12 rotates at the same speed as the first shaft 11 through the first sun gear 41, the planetary gear 43 and the second sun gear 42. When the transmission ratio changing motor 14 is driven, the carrier 44 rotates, and the second shaft 12 rotates at a higher speed through the planetary gear 43 and the second sun gear 42.

  In other words, when the transmission ratio changing motor 14 is rotationally driven, the second angle based on the motor driving is set to the rotational angle of the first shaft 11 based on the operation of the steering wheel 2 (equal to the steering angle θh in this embodiment). By adding the rotation angle of the shaft 12 (hereinafter referred to as “act angle θact”), the ratio θr of the rotation angle θr (θr = θh + θact) of the second shaft 12 to the steering angle θh, which is the rotation angle of the first shaft 11. / Θh is varied. Note that “addition” includes not only addition but also subtraction. On the other hand, when the transmission ratio changing motor 14 is not driven, the act angle θact is 0, so the ratio θr / θh is 1.

FIG. 3 is a block diagram showing a schematic configuration of the transmission ratio variable device ECU 32.
The transmission ratio variable device ECU 32 includes a microcomputer 61 and a drive circuit (three-phase inverter circuit) 62 that is controlled by the microcomputer 61 and supplies power to the transmission ratio changing motor 14. The microcomputer 61 includes a CPU and a memory (ROM, RAM, etc.), and functions as a plurality of function processing units by executing a predetermined program.

The plurality of function processing units include a target act angle calculation unit 71, an angle deviation calculation unit 72, a proportional control unit 73, an instruction voltage generation unit 74, a PWM control unit 75, and an actual act angle calculation unit 76. A disturbance determining unit 77 and a proportional gain setting unit 78 are included.
The target act angle calculation unit 71 calculates a target act angle θact ^* based on detection values of various vehicle running states that affect steering. In this embodiment, the target act angle calculator 71 calculates the target act angle θact ^* based on the steering angle θh detected by the steering angle sensor 21 and the vehicle speed V detected by the vehicle speed sensor 25. For example, the target act angle calculation unit 71 increases the ratio of the rotation angle θr of the second shaft 12 to the rotation angle θh of the first shaft 11 as the target act angle θact ^* increases as the vehicle speed decreases and the absolute value of the steering angle decreases. The target act angle θact ^* is calculated so that θr / θh increases. Note that the target act angle calculation unit 71 may calculate the target act angle θact ^* in consideration of the steering speed which is a time differential value of the steering angle θh in addition to the steering angle θh and the vehicle speed V.

The actual act angle calculator 76 calculates the actual act angle (actual act angle θact) based on the rotation angle θd of the rotor of the transmission ratio changing motor 20 detected by the rotation angle sensor 22.
The angle deviation calculator 72 is a deviation (angle deviation Δθact (= θact ^* − ⁾ between the target act angle θact ^* calculated by the target act angle calculator 71 and the actual act angle θact calculated by the actual act angle calculator 76. θact)) is calculated.

The proportional control unit 73 calculates the command current value by multiplying the angular deviation Δθact by the proportional gain K _P. The command voltage generation unit 74 generates U-phase, V-phase, and W-phase command voltages (three-phase command voltage) based on the command current value obtained by the proportional control unit 73. The PWM control unit 75 has a duty ratio U-phase PWM control signal, V-phase PWM control signal, and W-phase PWM control signal corresponding to the U-phase, V-phase, and W-phase command voltages calculated by the command voltage generation unit 74, respectively. Is supplied to the drive circuit 62.

The drive circuit 62 includes a three-phase inverter circuit corresponding to the U phase, the V phase, and the W phase. The power element constituting the three-phase inverter circuit is controlled by the PWM control signal supplied from the PWM control unit 75 so that the voltage corresponding to the three-phase indicating voltage is transferred to the transmission ratio changing motor. 14 applied to the stator windings of each phase.
The angle deviation calculation unit 72 and the proportional control unit 73 constitute feedback control means. By this action of the feedback control means, the actual act angle θact is controlled to be equal to the target act angle θact ^* .

  The disturbance determination unit 77 determines whether or not a disturbance is input to the second shaft 12 via the steered wheels 3L and 3R, the steering mechanism 4 and the intermediate shaft 9. In this embodiment, the disturbance determination unit 77 determines that a disturbance is input to the second shaft 12 when the output signal of the torque sensor 23 includes a frequency component higher than a predetermined frequency. The predetermined frequency is set to 10 Hz, for example. When the vehicle is traveling on a rough road such as a gravel road, the frequency component higher than the predetermined frequency is included in the output signal of the torque sensor 23, so that the disturbance determination unit 77 causes the second shaft 12 to be included. It is determined that a disturbance is input.

The proportional gain setting unit 78 sets the proportional gain K _P in the proportional control unit 73. The proportional gain setting unit 78 includes a first gain setting unit 78A, a second gain setting unit 78B, a first multiplication unit 78C, and a second multiplication unit 78D. The first gain setting unit 78A sets the first gain G1 (0 <G1 ≦ 1) based on the determination result of the disturbance determination unit 77. Specifically, when it is determined by the disturbance determination unit 77 that no disturbance is input to the second shaft 12, the first gain setting unit 78A sets the first gain G1 to 1. On the other hand, when the disturbance determining unit 77 determines that a disturbance is input to the second shaft 12, the first gain setting unit 78A sets the first gain G1 to a predetermined value smaller than 1, for example, 0.5. Set to.

The second gain setting unit 78B sets the second gain G2 (0 <G2 ≦ 1) based on the vehicle speed V detected by the vehicle speed sensor 25. Specifically, the second gain setting unit 78B sets the second gain G2 to a larger value as the vehicle speed V increases. This is because, by increasing the proportional gain K _P when the vehicle speed V which accuracy of the steering is required is high, because to increase the responsiveness of the feedback control.

The first multiplier 78C multiplies the first gain G1 and the second gain G2. The second multiplier unit 78D is the base proportional gain K _PO is a predetermined basic value of the proportional gain K _P, multiplies the calculation result of the first multiplication portion 78C. Computation result of the second multiplication section _{78D (G1 · G2 · K PO} ) is, as a proportional gain _{K P,} is set to proportional control unit 73.
If the disturbances to the second shaft 12 by the disturbance determination section 77 is judged not to be inputted, the first gain G1 is set to 1, the proportional gain K _P is set to a relatively large value . On the other hand, when the disturbance determining unit 77 determines that a disturbance is input to the second shaft 12, the first gain G1 is set to a predetermined value smaller than 1, so that the proportional gain K _P is relatively low. Set to a small value.

When the vehicle is traveling on a rough road such as a gravel road, the steered wheels 3L and 3R vibrate, and this vibration is transmitted to the second shaft 12. In this case, if the proportional gain K _P is set to a large value, the feedback control response is high, and the transmission ratio changing motor 14 changes the turning angle of the steered wheels 3L and 3R (actual act angle). Torque is generated in a direction that hinders (change in θact). As a result, even if the vibration of the second shaft 12 is transmitted to the planetary gear 43 via the second sun gear 42, the carrier 44 does not rotate, so that the vibration of the second shaft 12 causes the second sun gear 42, the planetary gear 43, and It is transmitted to the first shaft 11 via the first sun gear 41. For this reason, the steering wheel 2 connected to the first shaft 11 vibrates, and the driver's steering feeling deteriorates. Further, when the steering wheel 2 vibrates, the target act angle θact ^* varies, and the transmission ratio changing motor 14 may be driven alternately in the forward and reverse directions.

In this embodiment, when the vehicle is traveling on a rough road such as a gravel road, it is determined that the disturbance is input to the second shaft 12 by the disturbance determination unit 77, and the proportional gain setting unit 78 determines the proportional gain. K _P is set to a value smaller than the normal value. Thereby, since the responsiveness of the feedback control is lowered, torque for preventing a change in the turning angle of the steered wheels 3L, 3R (change in the rotation angle of the second shaft 12) is generated from the transmission ratio changing motor 14. Can be suppressed. As a result, when the vibration of the second shaft 12 is transmitted to the planetary gear 43 via the second sun gear 42, the carrier 44 rotates. Thereby, the vibration of the second shaft 12 is absorbed by the differential mechanism 13, and the vibration of the second shaft 12 is hardly transmitted to the first shaft 11. For this reason, it can suppress that a driver | operator's steering feeling deteriorates, and can suppress that the transmission ratio change motor 14 is driven by the forward / reverse direction alternately.

FIG. 4 is a block diagram showing a schematic configuration of another example of the ECU for variable transmission ratio device.
4, the same components as those shown in FIG. 3 are denoted by the same reference numerals as those in FIG.
The microcomputer 61A in the transmission ratio variable device ECU 32A further includes a differential control unit 81, a subtraction unit 82, and a differential gain setting unit 79. The differential control unit 81 and the subtraction unit 82 are provided to reduce overshoot when the transmission ratio changing motor 14 is stopped. Differential gain setting unit 79 is provided for setting the derivative gain K _D in the differential control unit 81.

Differential control unit 81, the actual act angle θact computed by the actual act angle calculation unit 76, by multiplying the s · K _D, calculates a current correction value. s is a differential operator, and _KD is a differential gain.
The subtracting unit 82 corrects the command current value calculated by the proportional control unit 73 by subtracting the current correction value calculated by the differentiation control unit 81 from the command current value calculated by the proportional control unit 73. The command voltage generation unit 74 generates a command voltage based on the corrected command current value.

  The differential gain setting unit 79 includes a third gain setting unit 79A, a fourth gain setting unit 79B, a third multiplication unit 79C, and a fourth multiplication unit 79D. The third gain setting unit 79A sets the third gain G3 (1 ≦ G3 <2) based on the determination result of the disturbance determination unit 77. Specifically, when it is determined by the disturbance determination unit 77 that no disturbance is input to the second shaft 12, the third gain setting unit 79A sets the third gain G3 to 1. On the other hand, when it is determined by the disturbance determination unit 77 that a disturbance is input to the second shaft 12, the third gain setting unit 79A sets the third gain G3 to a value greater than 1, for example, 1.5. Set.

The fourth gain setting unit 79B sets a fourth gain G4 (0 <G4 ≦ 1) based on the vehicle speed V detected by the vehicle speed sensor 25. Specifically, the fourth gain setting unit 79B sets the fourth gain G4 to a larger value as the vehicle speed V increases. This is because, when the vehicle speed V is high accuracy of the steering is required, by increasing the derivative gain K _D, in order to enhance the effect of reducing the overshoot at stopping of the transmission ratio changing motor 14.

The third multiplication unit 79C multiplies the third gain G3 and the fourth gain G4. The fourth multiplier unit 79D is a preset basic value of the differential gain _{K D} (basic differential gain _{K DO),} multiplying the calculation result of the third multiplying unit 79C. The operation result of the fourth multiplier unit 79D is a derivative gain _{K D,} is set to the differential control unit 81.
In this modification, since the derivative control unit 81 and the subtraction unit 82 are provided, it is possible to reduce overshoot when the transmission ratio changing motor 14 is stopped. Further, the differential gain K _D of differential control unit 81, if it is determined that the disturbance to the second shaft 12 by the disturbance determination unit 77 is input, since is set to a value larger than usual, subtraction The corrected command current value obtained by the unit 82 can be further reduced. For this reason, when the disturbance is input into the 2nd shaft 12, the responsiveness of feedback control can be reduced more. Thereby, it is possible to more effectively suppress the vibration of the steered wheels 3L and 3R from being transmitted to the steering wheel 2 when a disturbance is input to the second shaft 12.

As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above-described embodiment, if it is determined that the disturbance to the second shaft 12 by the disturbance determination unit 77 is input, but the proportional gain K _P are reduced than normal, instead of this In addition to this, a change in the target act angle θact ^* output from the target act angle calculation unit 71 may be suppressed. Specifically, as shown by broken lines in FIGS. 3 and 4, the determination result of the disturbance determination unit 77 is given to the target act angle calculation unit 71. When it is determined by the disturbance determination unit 77 that a disturbance is input to the second shaft 12, the target act angle calculation unit 71 holds the target act angle θact ^* that is currently set without being changed. . In this way, since the target act angle θact ^* can be prevented from fluctuating at the time of disturbance input, it is possible to prevent the transmission ratio changing motor from being driven alternately in the forward and reverse directions at the time of disturbance input.

  In addition, various design changes can be made within the scope of matters described in the claims.

  DESCRIPTION OF SYMBOLS 2 ... Steering member, 4 ... Steering mechanism, 7 ... Transmission ratio variable apparatus, 11 ... 1st shaft, 12 ... 2nd shaft, 13 ... Differential mechanism, 14 ... Transmission ratio change motor, 32, 32A ... Transmission ratio ECU for variable device, 71 ... target act angle calculation unit, 72 ... angle deviation calculation unit, 73 ... proportional control unit, 76 ... actual act angle calculation unit, 77 ... disturbance determination unit, 78 ... proportional gain setting unit

Claims (4)

A differential mechanism that couples a first shaft coupled to the steering member and a second shaft coupled to the steering mechanism such that the transmission ratio of rotation between the two shafts can be changed;
A transmission ratio changing motor that changes the transmission ratio of rotation between the two shafts by driving the differential mechanism;
Motor control means for controlling the transmission ratio changing motor;
Disturbance determination means for determining whether a disturbance is input to the second shaft via the steering mechanism;
The motor is configured to suppress the disturbance input to the second shaft from being transmitted to the first shaft when the disturbance determination unit determines that the disturbance is input to the second shaft. A vehicle steering apparatus, comprising: control mode changing means for changing a control mode by the control means. A rotation angle detecting means for detecting a rotation angle of the transmission ratio changing motor;
The motor control means is configured to change the transmission ratio so that a feedback value obtained from the rotation angle detected by the rotation angle detection means becomes equal to a target value for controlling the rotation angle of the transmission ratio changing motor. It is configured to feedback control the motor,
The control mode changing means includes means for reducing a control gain of feedback control in the motor control means when it is determined by the disturbance detection means that a disturbance is input to the second shaft. The vehicle steering device according to claim 1. A rotation angle detecting means for detecting a rotation angle of the transmission ratio changing motor;
The motor control means is configured to change the transmission ratio so that a feedback value obtained from the rotation angle detected by the rotation angle detection means becomes equal to a target value for controlling the rotation angle of the transmission ratio changing motor. It is configured to feedback control the motor,
The vehicle control device according to claim 1, wherein the control mode changing unit includes a unit that suppresses a change in the target value when it is determined by the disturbance detection unit that a disturbance is input to the second shaft. Steering device. Including torque detection means for detecting steering torque;
The disturbance detection unit is configured to determine that a disturbance is input to the second shaft when the output signal of the torque detection unit includes a frequency component higher than a predetermined frequency. The vehicle steering device according to any one of claims 1 to 3.

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