JP2015120405A - Vehicle steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle steering device capable of attaining a steering feel without making a drive feel fatigue when a vehicle turns right or left.SOLUTION: If a direction indicator of a vehicle outputs a direction indication signal Sind and the absolute value of a variation in a steering torque τ detected by a torque sensor is predetermined torque amount τ0 or larger, then it is determined that the vehicle enters a state of turning right or left and that a driver enters a state of turning a steering wheel sharply, and a gear transfer ratio is set to a maximum ratio. As a result, it is possible to maintain an appropriate steering feel without making a driver feel fatigue since the driver is hardly required to turn the steering wheel to the right or left when the vehicle turns right or left.

Description

  The present invention relates to a vehicle steering apparatus.

  Conventionally, there is a steering apparatus including a gear transmission ratio variable control system that varies a transmission ratio (gear ratio) of a steered wheel with respect to a steering angle (steering angle) of a steering wheel according to a vehicle state (see, for example, Patent Document 1). ).

JP 2002-240734 A

  However, in the transmission ratio variable control system mounted on such a steering device, the gear ratio is variable depending on the vehicle speed. Therefore, at low vehicle speeds, the tire can be greatly cut with a little steering, but at medium vehicle speeds or higher. If this happens, the steering wheel must also be increased in order to cut the tire largely. In particular, when turning right or left of the vehicle, it is necessary to turn the steering wheel greatly, so that the feeling of fatigue is increased and the steering feeling may be deteriorated.

  An object of the present invention is to provide a vehicle steering apparatus that can provide a steering feeling without fatigue when the vehicle turns left or right.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a vehicle speed detecting means for detecting the speed of the vehicle, and a first of the steered wheels based on the motor drive at the first rudder angle of the steered wheels based on the steering operation. A transmission ratio variable device that varies the gear transmission ratio between the steering wheel and the steered wheels by adding a steering angle of 2, control means for controlling the transmission ratio variable device, and the control means for detecting the vehicle speed A vehicle steering apparatus for starting control for varying the gear transmission ratio according to a vehicle speed detected from the means, wherein the torque detection means detects a steering torque, and the vehicle traveling direction instruction means instructs a traveling direction of the vehicle. And the control means outputs when the vehicle traveling direction instruction means outputs a right / left turn instruction and the absolute value of the change amount of the steering torque detected from the torque detection means is equal to or greater than a predetermined torque value. And summarized in that to maximize the gear transmission ratio.

  That is, when the vehicle traveling direction instruction means outputs a right / left turn instruction and the absolute value of the change amount of the steering torque detected from the torque detection means is equal to or greater than a predetermined torque value, the vehicle enters a right / left turn state. Judging that the driver has entered a state in which the steering wheel is largely turned, the gear transmission ratio is maximized. As a result, when the driver makes a right or left turn of the vehicle, it is not necessary to almost turn the steering wheel, so that a good steering feeling without fatigue can be maintained.

According to a second aspect of the present invention, there is provided a determination unit that determines whether or not the vehicle is in a straight traveling state, and the control unit maximizes the gear transmission ratio and then determines that the vehicle is in a straight traveling state. The gist is to change the gear transmission ratio from the maximum to the normal gear transmission ratio.
According to the above configuration, when the vehicle goes straight, the configuration is changed to the normal gear transmission ratio instead of the excessive gear transmission ratio, so that the driver does not feel uneasy or uncomfortable. Steering feeling can be maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the steering apparatus for vehicles which can obtain the steering feeling without a feeling of fatigue at the time of the left-right turn of a vehicle can be provided.

The schematic block diagram of the steering apparatus for vehicles. The control block diagram of the steering device for vehicles. The detailed control block diagram of a gear ratio variable control calculating part. (A) (b) Operation | movement explanatory drawing of transmission ratio variable control. The flowchart which shows the process sequence of gear ratio maximum control.

Hereinafter, an embodiment in which the present invention is embodied in a vehicle steering apparatus including an electric power steering apparatus (EPS) and a transmission ratio variable apparatus will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a vehicle steering apparatus 1 according to the present embodiment, FIG. 2 is a control block diagram thereof, FIG. 3 is a detailed view thereof, and FIGS. 4 (a) and 4 (b) are transmission ratio variable controls. FIG. As shown in FIG. 1, a steering shaft 3 to which a steering wheel 2 is fixed is connected to a rack shaft 5 via a rack and pinion mechanism 4, and the rotation of the steering shaft 3 accompanying the steering operation is performed by the rack and pinion mechanism. 4 is converted into a reciprocating linear motion of the rack shaft 5. Then, by changing the rudder angle of the steered wheels 6, that is, the steered angle, by the reciprocating linear motion of the rack shaft 5, the traveling direction of the vehicle is changed. That is, in the present embodiment, a steering transmission system that connects the steering 2 and the steered wheels 6 is configured by the steering shaft 3, the rack and pinion mechanism 4, and the rack shaft 5 (and tie rods and knuckle arms that are not described in detail). Yes.

  The vehicle steering apparatus 1 of the present embodiment includes a gear ratio variable actuator 7 as a transmission ratio variable device that varies the transmission ratio (gear ratio) of the steered wheels 6 with respect to the steering angle (steering angle) of the steering 2, and a variable gear ratio. And an IFSECU 8 for controlling the operation of the actuator 7.

  More specifically, the steering shaft 3 includes a first shaft 9 to which the steering 2 is connected and a second shaft 10 to be connected to the rack and pinion mechanism 4. The variable gear ratio actuator 7 includes the first shaft 9 and the first shaft 9. A differential mechanism 11 for connecting the two shafts 10 and an IFS motor 12 for driving the differential mechanism 11 are provided. Then, the gear ratio variable actuator 7 adds the rotation based on the motor drive to the rotation of the first shaft 9 accompanying the steering operation and transmits it to the second shaft 10, thereby inputting the same to the rack and pinion mechanism 4. The rotation of the second shaft 10 is increased (or decelerated).

  That is, as shown in FIGS. 4 (a) and 4 (b), the gear ratio variable actuator 7 has the steered wheels 6 based on the motor drive to the first steered angle (steer steered angle θts) of the steered wheels 6 based on the steering operation. By adding the second steering angle (ACT angle θta), a transmission ratio variable device that varies the ratio of the steering angle θt of the steered wheels 6 to the steering angle θs of the steering wheel 2, that is, the gear transmission ratio, is configured. The IFSECU 8 (control means) controls the gear ratio variable actuator 7 through the supply of driving power to the IFS motor 12, thereby controlling the gear transmission ratio between the steering angle θs and the turning angle θt (transmission). Variable ratio control).

In this case, “addition” is defined to include not only addition but also subtraction, and so on. Further, when the “gear ratio of the steering angle θt to the steering angle θs” is expressed as an overall gear ratio (steering angle θt / steering angle θs), the ACT angle θta in the same direction as the steering angle θts is added. As a result, the overall gear ratio is increased (the steering angle θs is small, see FIG. 4A). Then, by adding the ACT angle θta in the reverse direction, the overall gear ratio becomes smaller (large steering angle θs, see FIG. 4B). In this embodiment, the steer turning angle θts constitutes the first steering angle,
The ACT angle θta constitutes the second steering angle.

  As shown in FIG. 1, the vehicle steering device 1 controls an EPS actuator 17 as an electric power steering device that applies an assist force for assisting a steering operation to the steering system, and the operation of the EPS actuator 17. EPS ECU 18 is provided.

  The EPS actuator 17 of the present embodiment is a rack assist type EPS actuator in which an EPS motor 22 as a driving source is provided on the rack shaft 5, and the assist torque generated by the EPS motor 22 is generated by a ball screw mechanism ( (Not shown) is transmitted to the rack shaft 5. The EPS ECU 18 controls the assist force applied to the steering system by controlling the assist torque generated by the EPS motor 22 (power assist control).

  In the present embodiment, the IFSECU 8 that controls the gear ratio variable actuator 7 and the EPSECU 18 that controls the EPS actuator 17 are connected via an in-vehicle network (such as CAN) 23. A plurality of sensors for detecting the amount are connected.

  Specifically, the in-vehicle network 23 includes a steering sensor 24, a torque sensor 25 (torque detection means), a vehicle speed sensor 26 (vehicle speed detection means), a left front wheel speed sensor 60, a right front wheel speed sensor 61, and a left rear wheel speed sensor. 62, a right rear wheel speed sensor 63, a yaw rate sensor 64, and a direction indicator 65 (vehicle traveling direction indicating means) are connected. The steering angle θs, the steering torque τ, the vehicle speed V, the left front wheel speed Wfl, the right front wheel speed Wfr, the left rear wheel speed Wrl, the right rear wheel speed Wrr, the yaw rate γ, and the direction indicator signal detected by these sensors. Sind is input to the IFSECU 8 and the EPSECU 18 via the in-vehicle network 23.

  In the present embodiment, a known twin resolver type is adopted as the torque sensor 25, and the torque sensor 25 is provided on the second shaft 10 (pinion shaft) near the rack and pinion mechanism 4. . The IFSECU 8 and EPSECU 18 perform the transmission ratio variable control and the power assist control in an integrated manner by performing mutual communication via the in-vehicle network 23.

Next, the electrical configuration and control mode of the vehicle steering apparatus of this embodiment will be described.
As shown in FIG. 2, the IFSECU 8 includes an IFS microcomputer 31 that outputs a motor control signal, and an IFS drive circuit 32 that supplies drive power to the IFS motor 12 based on the motor control signal. Each control block shown in the figure is realized by a computer program executed by the IFS microcomputer 31 (EPS microcomputer 41) provided in the IFSECU 8 (EPSECU 18).

  The IFS microcomputer 31 includes a gear ratio variable control calculation unit 33 and a differential steer control calculation unit 34. The gear ratio variable control calculation unit 33 includes a steering angle θs, a vehicle speed V, a steering torque τ, and a left front wheel speed Wfl. A right front wheel speed Wfr, a left rear wheel speed Wrl, a right rear wheel speed Wrr, a yaw rate γ, and a direction indicator signal Sind indicating a right / left turn instruction are input.

  On the other hand, the steering speed ωs obtained by passing the vehicle speed V and the steering angle θs through the differentiator 30 is input to the differential steer control calculation unit 34. The gear ratio variable control calculation unit 33 calculates a gear ratio variable command angle θgr * that is a control target component for changing the gear transmission ratio according to the vehicle speed V, and the differential steer control calculation unit 34 calculates the steering speed. A differential steer command angle θls *, which is a control target component for improving the responsiveness of the vehicle, is calculated according to ωs.

  The gear ratio variable command angle θgr * and the differential steer command angle θls * calculated by the gear ratio variable control calculation unit 33 and the differential steer control calculation unit 34 are input to the adder 35. The adder 35 calculates the ACT command angle θta * by superimposing the gear ratio variable command angle θgr * and the differential steer command angle θls *.

  Further, the motor rotation angle θmvg output from the IFS rotation angle sensor 36 provided in the IFS motor 12 is input to the IFS microcomputer 31, and the ACT command angle calculated by the adder 35 is input. θta * is input to the position control calculation unit 38 together with the ACT angle θta calculated based on the motor rotation angle θmvg. Then, the position control calculation unit 38 calculates the current command Icmd by feedback calculation based on the deviation between the ACT command angle θta * and ACTθta, which is a command value, and outputs the current command Icmd to the IFS motor control signal output unit 39.

  The IFS motor control signal output unit 39 outputs the motor control signal generated based on the current command Icmd to the IFS drive circuit 32, and the drive power based on the motor control signal is supplied to the IFS motor 12. Thus, the operation of the IFS motor 12, that is, the gear ratio variable actuator 7 is controlled.

  On the other hand, the EPSECU 18 also includes an EPS microcomputer 41 that outputs a motor control signal and an EPS drive circuit 42 that supplies drive power to the EPS motor 22 based on the motor control signal, like the IFSECU 8.

  The EPS microcomputer 41 includes an assist force calculator 43 that calculates a current command value Iq * as a control target of the assist force applied to the steering system. The assist force calculator 43 includes the torque sensor 25 and the vehicle speed. The steering torque τ and the vehicle speed V detected by the sensor 26 are input. Then, the assist force calculation unit 43 calculates a current command value Iq * that is a control target of power assist control based on the steering torque τ and the vehicle speed V.

  Further, the EPS microcomputer 41 includes an actual current value Ips supplied to the EPS motor 22 detected by the current sensor 44 and a motor rotation angle output from the EPS rotation angle sensor 45 provided in the EPS motor 22. θmps is input, and the current command value Iq * calculated by the assist force calculation unit 43 is input to the EPS motor control signal output unit 46 together with the actual current value Ips and the motor rotation angle θmps. The The EPS motor control signal output unit 46 generates a motor control signal by performing current feedback control so that the detected actual current value Ips of the EPS motor 22 follows the current command value Iq *.

  In the present embodiment, the EPS motor 22 employs a brushless motor that is rotated by three-phase (U, V, W) driving power, and the current sensor 44 has a current value (Iu) for each phase. , Iv, Iw) is output to the EPS motor control signal output unit 46 as the actual current value Ips. The EPS motor control signal output unit 46 converts the detected phase current values (Iu, Iv, Iw) into d and q axis current values in the d / q coordinate system (d / q conversion). The current feedback control is performed.

  That is, the assist force calculation unit 43 outputs the current command value Iq * as the q-axis current command value to the EPS motor control signal output unit 46, and the EPS motor control signal output unit 46 sets the q-axis current command value to the q-axis current command value. Each phase voltage command value (Vu *, Vv *, Vw *) is calculated by performing feedback control calculation to follow the q-axis current value calculated by the d / q conversion. Then, the EPS motor control signal output unit 46 outputs the motor control signal generated based on each phase voltage command value to the EPS drive circuit 42, and the drive power based on the motor control signal is supplied to the EPS motor 22. By being supplied, the operation of the EPS motor 22, that is, the EPS actuator 17 is controlled.

(Maximum gear ratio control)
Next, the aspect of the maximum gear ratio control in the vehicle steering apparatus of the present embodiment will be described.
As shown in FIG. 3, in this embodiment, the gear ratio variable control calculation unit 33 includes a gear ratio determination unit 53 that determines the normal gear ratio control and the maximum gear ratio control, and the variable gear ratio used during the normal gear ratio control. A map 50, and a gear ratio variable maximum map 52 used in the gear ratio maximum control;
A gear ratio switch 51 that switches the gear ratio by a gear ratio maximum flag FLGgr that is an output signal from the gear ratio determination unit 53 is provided.

  More specifically, when gear ratio normal control is selected, first, the gear ratio grr is output based on the vehicle speed V input to the gear ratio variable map 50. Next, the output gear ratio grr is integrated with the input steering angle θs by the integrator 54. Then, the steering angle θs is further added to the accumulated grr * θs state quantity by the adder 55, and a gear ratio variable command angle θgr * for normal gear ratio control is output.

  On the other hand, when the maximum gear ratio control is selected, first, the maximum gear ratio grrmax is output from the gear ratio variable maximum map 52. Next, the output maximum gear ratio grrmax is integrated with the input steering angle θs by the integrator 56. Then, the steering angle θs is further added to the accumulated grrmax * θs state quantity by the adder 57, and a gear ratio variable command angle θgr * for maximum gear ratio control is output.

  In the present embodiment, the gear ratio determination unit 53 is supplied with a direction indicator signal Sind indicating a right / left turn instruction and a steering torque τ, and the gear ratio determination unit 53 receives the input right When the direction indicator signal Sind indicating a left turn instruction is in an ON state and the absolute value of the change amount of the steering torque τ is larger than a predetermined steering torque value, the vehicle enters an intersection or the like and performs a left / right turn operation. It is determined that it has started, and the maximum gear ratio control is executed.

  In the present embodiment, the gear ratio determination unit 53 receives the yaw rate γ, the left front wheel speed Wfl, the right front wheel speed Wfr, the left rear wheel speed Wrl, and the right rear wheel speed Wrr. Then, the gear ratio determination unit 53 has the absolute value of the input yaw rate γ equal to or smaller than the predetermined yaw rate value, the absolute value of the difference between the left front wheel speed Wfl and the right front wheel speed Wfr is equal to or smaller than the predetermined speed value, and When the absolute value of the difference between the rear wheel speed Wrl and the right rear wheel speed Wrr is equal to or less than a predetermined speed value, it is determined that the vehicle has been in a straight traveling state (determination means), and gear ratio normal control is executed.

  More specifically, in this embodiment, when the gear ratio determination unit 53 determines that the vehicle state needs to execute the maximum gear ratio control, the gear ratio determination unit 53 sends the gear ratio switcher 51 to the gear ratio switcher 51. The input gear ratio maximum flag FLGgr signal is turned on. As a result, the gear ratio switching unit 51 connects the contact 51c and the contact 51b, calculates the gear ratio variable maximum value from the gear ratio variable maximum map 52, and outputs the gear ratio variable command angle θgr *.

  On the other hand, in the present embodiment, when the gear ratio determination unit 53 determines that the vehicle state does not need to execute the maximum gear ratio control, the gear ratio determination unit 53 inputs the gear ratio switching unit 51. The maximum gear ratio flag FLGgr is turned off. As a result, the gear ratio switching unit 51 connects the contact 51c and the contact 51a, calculates the gear ratio according to the vehicle speed V from the gear ratio variable map 50, and outputs the gear ratio variable command angle θgr *.

Next, the processing procedure of the maximum gear ratio control in this embodiment will be described.
As shown in the flowchart of FIG. 5, the IFS microcomputer 31 uses, as sensor values, the steering angle θs, the steering torque τ, the vehicle speed V, the left front wheel speed Wfl, the right front wheel speed Wfr, the left rear wheel speed Wrl, and the right rear wheel speed. A direction indicator signal Sind indicating Wrr, yaw rate γ, and right / left turn instruction is acquired from the in-vehicle network 23 (step S101).

  Subsequently, the IFS microcomputer 31 determines whether or not the direction indicator signal Sind indicating the right / left turn instruction is on (step S102). When the IFS microcomputer 31 determines that the direction indicator signal Sind indicating the right / left turn instruction is on (step S102: YES), the IFS microcomputer 31 subsequently changes the amount of change in the steering torque τ. It is determined whether or not the absolute value of is greater than or equal to a predetermined torque value τ0 (step S103).

  If the absolute value of the change amount of the steering torque τ is equal to or larger than the predetermined torque value τ0 (step S103: YES), the IFS microcomputer 31 subsequently sets the gear ratio maximum flag FLGgr. (Step S104). Then, the IFS microcomputer 31 performs maximum gear ratio control (step S105).

  Next, the IFS microcomputer 31 determines that the absolute value of the yaw rate γ is equal to or smaller than the predetermined yaw rate γ0, the absolute value of the difference between the left front wheel speed Wfl and the right front wheel speed Wfr is equal to or smaller than the predetermined wheel speed difference ε0, and the left rear wheel speed. It is determined whether or not the absolute value of the difference between Wrl and the right rear wheel speed Wrr is equal to or smaller than a predetermined wheel speed difference ε0 (step S106).

  The IFS microcomputer 31 determines that the absolute value of the yaw rate γ is equal to or smaller than the predetermined yaw rate γ0, the absolute value of the difference between the left front wheel speed Wfl and the right front wheel speed Wfr is equal to or smaller than the predetermined wheel speed difference ε0, and the left rear wheel speed Wrl. And the absolute value of the difference between the right rear wheel speed Wrr is equal to or less than the predetermined wheel speed difference ε0 (step S106: YES), the determination means determines that the vehicle is traveling straight and resets the maximum gear ratio flag FLGgr. (Step S107). Next, the IFS microcomputer 31 executes normal gear ratio control (step S108) and ends the process.

  On the other hand, the IFS microcomputer 31 determines that the absolute value of the yaw rate γ is equal to or smaller than the predetermined yaw rate γ0, the absolute value of the difference between the left front wheel speed Wfl and the right front wheel speed Wfr is equal to or smaller than the predetermined wheel speed difference ε0, and the left rear wheel speed Wrl. If the absolute value of the difference between the right rear wheel speed Wrr is not equal to or less than the predetermined wheel speed difference ε0 (step S106: NO), the determination unit determines that the vehicle is not in the straight traveling state, and returns to step S105. Further, the IFS microcomputer 31 determines that the absolute value of the change amount of the steering torque τ is smaller than the predetermined torque value τ0 (step S103: NO) or the direction indicator signal Sind indicating the right / left turn instruction is not on (step S103). In S102: NO), normal gear ratio control is executed (step S108), and the process is terminated.

As described above, according to the present embodiment, the following operations and effects can be obtained.
When the direction indicator 65 outputs a direction indicator signal Sind indicating a right / left turn instruction and the absolute value of the change amount of the steering torque τ detected from the torque sensor 25 is equal to or greater than a predetermined torque value τ0, the vehicle The gear transmission ratio is maximized by judging that the driver has entered a state of turning right and left, and that the driver has entered a state of turning the steering wheel. As a result, when the driver makes a right or left turn of the vehicle, it is not necessary to almost turn the steering wheel, so that a good steering feeling without fatigue can be maintained.

  After the gear transmission ratio is maximized, the gear transmission ratio is changed from the maximum to the normal gear transmission ratio when the determination means determines that the vehicle travels straight. As a result, when the vehicle goes straight, it is changed to a normal gear transmission ratio instead of an excessive gear transmission ratio, so that a good steering feeling that does not give the driver anxiety or discomfort is maintained. can do.

In addition, you may change this embodiment as follows.
In the present embodiment, the torque sensor 25 is provided on the second shaft 10 (pinion shaft) in the vicinity of the rack and pinion mechanism 4. However, the present invention is not limited to this, and the torque sensor 25 may be provided at other locations such as a column shaft. Well, the format is not limited to the twin resolver type.

In the present embodiment, the gear ratio variable actuator 7 constituting the transmission ratio variable device is installed on the intermediate shaft. However, the gear ratio variable actuator 7 is not limited to this, as long as it is provided in the middle of the steering transmission system. The installation location is not limited.

In the present embodiment, the absolute value of the yaw rate γ is a predetermined yaw rate value γ0 or less, the absolute value of the difference between the left front wheel speed Wfl and the right front wheel speed Wfr is a predetermined speed value ε0 or less, and the left rear wheel speed Wrl When the absolute value of the difference between the right wheel speed Wrr and the right rear wheel speed Wrr is equal to or less than the predetermined speed value ε0, it is determined that the vehicle is in a straight traveling state, but the straight traveling state may be determined only by the wheel speeds of the four wheels. .

1: Steering device for vehicle, 2: Steering,
3: Steering shaft, 4: Rack and pinion mechanism, 5: Rack shaft,
6: steered wheel, 7: variable gear ratio actuator, 8: IFSECU (control means),
9: first shaft, 10: second shaft, 11: differential mechanism,
12: IFS motor, 17: EPS actuator, 18: EPSECU,
22: EPS motor, 23: In-vehicle network (CAN, etc.),
24: steering sensor, 25: torque sensor (torque detection means),
26: Vehicle speed sensor (vehicle speed detection means), 30: Differentiator,
31: IFS microcomputer, 32: IFS drive circuit,
33: Variable gear ratio control calculation unit 34: Differential steer control calculation unit 35: Adder
36: IFS rotation angle sensor, 38: Position control calculation unit,
39: IFS motor control signal output unit,
41: EPS microcomputer, 42: EPS drive circuit,
43: assist force calculation unit, 44: current sensor, 45: rotation angle sensor for EPS,
46: EPS motor control signal output unit, 50: Gear ratio variable map,
51: Gear ratio switcher, 51a, 51b, 51c: Contacts
52: Gear ratio variable maximum map, 53: Gear ratio determination unit,
54, 56: integrator, 55, 57: adder,
60: Front left wheel speed sensor, 61: Front right wheel speed sensor,
62: Left rear wheel speed sensor, 63: Right rear wheel speed sensor,
64: Yaw rate sensor, 65: Direction indicator (vehicle traveling direction instruction means),
θs: steering angle, θt: steering angle,
θts: Steer turning angle, θta: ACT angle,
τ: steering torque, V: vehicle speed, ωs: steering speed,
grr: gear ratio, grrmax: maximum gear ratio, θgr *: gear ratio variable command angle,
θls *: differential steering command angle, θta *: ACT command angle,
θmvg: motor rotation angle, Icmd: current command,
Iq *: current command value, Ips: actual current value,
θmps: Motor rotation angle,
Iu, Iv, Iw: current value of each phase,
Vu *, Vv *, Vw *: Voltage command values for each phase,
τ0: predetermined torque value,
Wfl: front left wheel speed, Wfr: front right wheel speed,
Wrl: left rear wheel speed, Wrr: right rear wheel speed, ε0: predetermined wheel speed difference,
γ: Yaw rate, γ0: Predetermined yaw rate, Sind: Direction indicator signal,
FLGgr: Maximum gear ratio flag

Claims (2)

Vehicle speed detection means for detecting the speed of the vehicle;
A transmission ratio variable device that varies the gear transmission ratio between the steering wheel and the steered wheel by adding the second rudder angle of the steered wheel based on the motor drive to the first steered angle of the steered wheel based on the steering operation. When,
Control means for controlling the transmission ratio variable device;
The control means is a vehicle steering device that starts control to vary the gear transmission ratio according to the vehicle speed detected from the vehicle speed detection means,
Torque detecting means for detecting steering torque;
Vehicle traveling direction indicating means for instructing the traveling direction of the vehicle;
The control means outputs the gear transmission when the vehicle traveling direction instruction means outputs a right / left turn instruction and the absolute value of the change amount of the steering torque detected from the torque detection means is equal to or greater than a predetermined torque value. Maximizing the ratio,
A vehicle steering apparatus characterized by the above. The vehicle steering apparatus according to claim 1,
A determination means for determining whether or not the vehicle is in a straight traveling state;
The control means, after maximizing the gear transmission ratio, changing the gear transmission ratio from the maximum to a normal gear transmission ratio when the determination means determines that the vehicle is traveling straight;
A vehicle steering apparatus characterized by the above.

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