JP2015067218A - Vehicle steering device and self-excited vibration detection method of steering wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop a lead steer control more reliably and quickly.SOLUTION: A vehicle steering device comprises: a steering shaft 12 having a first shaft 11a connected to a steering wheel 10 and a second shaft 11b that comprises a pinion 18 engaging with a rack shaft 20; a steering angle ratio variable actuator 14 for changing a steering angle ratio by relatively rotating and driving the second shaft to the first shaft; a steering angle sensor 26; a torque sensor 27; and a steering controller 30 for controlling the steering angle ratio variable actuator 14 so as to perform execution and stop of a lead steer operation. During the execution of the lead steer operation, the steering controller 30 stops the lead steer operation when the steering wheel 10 is in a state of turning back, and when a direction of a rotation angular acceleration of the steering wheel 10 and a direction of a torque applied to the second shaft 11b are different from each other.

Description

  The present invention relates to a vehicle steering apparatus including steering angle ratio variable means for changing a transmission ratio (steering angle ratio) between a steering angle of a steering apparatus (hereinafter referred to as steering) and an actual steered wheel, and steering. The present invention relates to a method for detecting self-excited vibration of a wheel (steering wheel).

  Conventionally, it includes a motor-driven steering angle ratio variable mechanism that can change the transmission ratio (steering angle ratio) between the steering angle of the steered wheels and the steered wheels, and the steering wheel according to the vehicle speed and the steering angle. The turning angle of the steered wheel based on the motor drive is added to the steered angle of the steered wheel based on the operation of the steering wheel (also referred to as the steering wheel operation in the alias, but hereinafter referred to as the steered wheel operation). A vehicle steering apparatus having a so-called active steering function is known.

  In this type of vehicle steering device, the steering angle ratio variable mechanism has a motor control program set so that the steering angle responsiveness of the steered wheels when the driver is operating the steered wheels is improved. Yes. For this reason, when the driver performs a letting operation while the steering wheel is in the incision steering state, that is, by using the self-aligning torque that acts on the steered wheel, the driver tries to return the steered wheel to the neutral (straight) position. (Including a state in which a hand is attached but the vehicle is not substantially steered), as described in detail in “Mode for Carrying Out the Invention”, the phenomenon that the steering wheel vibrates in the rotation direction ( Self-excited vibration) occurs. Such self-excited vibration of the steered wheels does not impair the driving performance and safety of the vehicle, but may give the driver a sense of discomfort and anxiety.

  In recent years, as a technique for suppressing such self-excited vibration of a steering wheel, a vehicle steering apparatus as disclosed in Patent Document 1 has been proposed. In this vehicle steering device, it is determined whether or not a hand-off operation is being performed, and when the hand-off operation is being performed, a control (lead steer control) for adding the turning angle of the steered wheels by motor driving is performed. By stopping or changing the target turning angle, the occurrence of self-excited vibration of the steered wheels is suppressed. In this case, whether or not the hand-off operation is being performed is determined based on the output value (steering angle) of the steering angle sensor, the target turning angle (steering angle of the steered wheels) set based on the steering angle, etc., the steering angle Based on parameters such as the rotation angle of the motor of the ratio variable mechanism and the vehicle speed, the value of the parameter satisfies a predetermined condition, and whether or not the satisfaction state continues for a certain period of time is performed.

JP 2007-118645 A

  The conventional vehicle steering device is effective in suppressing the self-excited vibration of the steering wheel. However, since it is determined whether or not the hand-off operation is performed using many parameters, an error factor is determined. There are many. In addition, since it is necessary for the parameter to satisfy a predetermined condition for a certain period of time, a delay may occur in the processing for stopping the read steer control. Therefore, there is room for improvement in this respect.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for more quickly stopping lead steer control in order to suppress self-excited vibrations of a steered wheel caused by hand-off operation. And

  In order to solve the above-described problems, a vehicle steering apparatus according to the present invention includes a first shaft that is connected to a steering wheel and rotates integrally with the steering wheel, and a second shaft that includes a pinion that meshes with the steering rack. The steering wheel is interposed between the first shaft and the second shaft, and the second shaft is driven to rotate relative to the first shaft. Steering angle ratio variable means for changing the steering angle ratio, which is a ratio of turning angles, first detection means for detecting a physical quantity that changes with rotation of the steered wheels and the direction of the change, and the first shaft Based on the detection results of the second detection means for detecting the direction of the torque and the first and second detection means, the turning angle of the steered wheel based on the steered wheel operation is the same as the steered angle of the steered wheel. Rudder angle ratio by adding Control means for controlling the steering angle ratio varying means to execute and stop the lead steer operation to be changed, and the control means is in a state in which the steered wheels are switched back during execution of the lead steer operation. In addition, the lead steer operation is stopped when the physical quantity, that is, the rotational angular acceleration direction of the steering wheel and the direction of the torque applied to the second shaft are different from each other.

  According to this vehicle steering system, after the steering wheel is turned and steered, the self-aligning torque that acts on the steered wheel is used to release the steered wheel to the neutral (straight) position (by attaching the hand to the steered wheel). However, even if a self-excited vibration is generated in the steered wheel, this self-excited vibration can be quickly eliminated. That is, when the steering wheel is returned to the neutral (straight forward) position in this way, the steering shaft is rotated by the self-aligning torque, and the steering angle ratio varying means receives the rotation and rotationally drives the second shaft. Thus, the first shaft in the released state rotates (returns) in the reverse direction. This is the first wave of self-excited vibration generated in the steering wheel. If the steered wheel is gripped and steered, the steered wheel does not rotate in the reverse direction in this way, and the direction of the steering acceleration of the first shaft and the direction of the torque of the second shaft are the same, When the first shaft rotates (returns) in the reverse direction as described above, the direction of the steering acceleration of the first shaft and the direction of the torque of the second shaft are temporarily reversed. Therefore, a phenomenon in which the direction of the steering acceleration of the first shaft and the direction of the torque of the second shaft are different in this way is detected, and the lead steering operation is stopped based on the detection, so that the self-excited vibration is quickly eliminated. Thus, the continuation of the self-excited vibration is suppressed.

  In this vehicle steering apparatus, the control means turns off the steering wheel when the direction of the steering angle of the steering wheel that is the physical quantity is different from the direction of the rotation speed of the steering wheel that is the physical quantity. Judged to be in the return state.

  According to this configuration, it is possible to accurately detect that the steered wheels are in the switchback state.

  In the above-described vehicle steering apparatus, a torque sensor that detects the rotational torque of the first shaft, and an actuator that provides the steering rack with an assist torque corresponding to the detected torque of the torque sensor that accompanies the operation of the steering wheel. When the power steering means further includes: the second detection means is preferably the torque sensor.

  According to this configuration, since the torque sensor of the power steering means is shared as a means for detecting the direction of torque applied to the second shaft, the configuration is rational.

  On the other hand, the present invention provides a steering shaft having a first shaft connected to a steered wheel and rotating integrally with the steered wheel, and a second shaft provided with a pinion meshing with a steering rack, the first shaft, and the first shaft The steering angle ratio, which is the ratio of the turning angle of the steered wheels to the steered angle of the steered wheels, is changed by interposing between the two shafts and rotating the second shaft relative to the first shaft. A steering angle ratio variable means, and a lead steer operation for changing the steering angle ratio by adding a steering angle in the same direction as the steering direction of the steered wheel to the steered angle of the steered wheel based on the operation of the steered wheel. A method of detecting self-excited vibration of the steering wheel in a vehicle to be executed, wherein the steering wheel is detected to be switched back based on a steering angle direction of the steering wheel and a rotational speed direction of the steering wheel. Switch back state detection And a vibration detection step of detecting the presence or absence of self-excited vibration based on the direction of rotational angular acceleration of the steering wheel and the direction of torque applied to the second shaft when the steering wheel is in a switchback state. In the switchback state detecting step, the steering wheel is determined to be in the switchback state when the steering angle direction of the steering wheel is the same as the rotation speed direction of the steering wheel, and the vibration In the detecting step, it is determined that the self-excited vibration is generated when the direction of the rotational angular acceleration of the steering wheel and the direction of the torque applied to the second shaft are opposite to each other.

  According to this method, a steered wheel that is generated when a hand-off operation is performed to return the steered wheel to a neutral (straight forward) position by using self-aligning torque that acts on the steered wheel after turning steering of the steered wheel. It is possible to quickly detect the self-excited vibration.

  As described above, according to the present invention, it is possible to quickly detect the self-excited vibration of the steered wheel due to the hand-off operation and quickly stop the lead steer control.

1 is a system configuration diagram of a vehicle steering apparatus according to the present invention. It is a block diagram which shows the control system of the steering apparatus for vehicles. (A) is a lead steer control, (b) is explanatory drawing explaining the lead steer control which reduces a steering angle, respectively. It is a flowchart which shows the example of control of the steering controller for stopping lead steer control. It is a graph which shows the change of the steering angle, steering speed, steering acceleration, and pinion torque accompanying rotation of a steering wheel. It is explanatory drawing explaining the mechanism in which a self-excited vibration generate | occur | produces in a steering wheel, (a) is the state which hold | gripped the steering wheel and carried out cutting steering, (b) is the state which released the hand after cutting steering, (C) is a state in which the steering angle ratio variable actuator is operated in accordance with the rotation of the steering wheel (steering shaft) by the self-aligning torque, whereby the steering wheel is inverted, and (d) the steering angle ratio is in accordance with the inversion of the steering wheel. Each of the states where the variable actuator is activated is shown. It is a graph which shows the relationship between a steering angle, the required angle | corner of a lead steer control, and a steering torque.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a system configuration diagram showing a vehicle steering device (a vehicle steering device to which a self-excited vibration detection method for a steered wheel) according to the present invention is applied. In the figure, reference numeral 10 denotes a steered wheel steered by the driver. The steering wheel 10 is fixed to one end of a steering shaft 12 that is rotatably supported by the vehicle body. A pinion 18 is provided at the other end of the steering shaft 12, and this pinion 18 meshes with a rack shaft 20 (corresponding to the steering rack of the present invention) connected to the steered wheels. That is, the rotation of the steering shaft 12 due to the operation of the steering wheel 10 is converted into a reciprocating movement in the axial direction of the rack shaft 20 via the pinion 18. (Steering angle) is changed.

  The steering shaft 12 includes a steering angle ratio variable actuator 14 for changing a steering angle ratio (steering angle / steering angle) that is a ratio of a steering angle of the steered wheels 22 to a steering angle of the steered wheels 10 (the present invention). Corresponding to the steering angle ratio variable means). Specifically, the steering shaft 12 includes a first shaft 11 a to which the steering wheel 10 is fixed, and a second shaft 11 b having the pinion 18, and these shafts 11 a and 11 b are connected via a steering angle ratio variable actuator 14. Connected to each other. The steering angle ratio variable actuator 14 includes a differential mechanism 15a composed of, for example, a planetary gear mechanism that connects the shafts 11a and 11b to each other, and a motor 15b that drives the differential mechanism 15a. The rotation by the drive of the motor 15b is added to the accompanying rotation of the first shaft 11a to rotate the second shaft 11b. That is, the steering angle ratio variable actuator 14 turns the steered wheel 22 based on the driving of the motor 15b to the steered angle (STE steered angle θa) of the steered wheel 22 based on the operation of the steered wheel 10 (steering angle θs). The steering angle ratio is changed by adding (adjusting) the steering angle (ACT angle θb).

  Further, the vehicle steering apparatus includes an EPS (electric power steering) actuator 24 (corresponding to the power steering means of the present invention) that adds torque (assist torque) to the steering torque generated by the driver's operation of the steering wheel 10. I have. The EPS actuator 24 of this example is a so-called rack assist type actuator, and is steered by transmitting a driving force (assist torque) of a motor 25 (shown in FIG. 2) to the rack shaft 20 via a screw feed mechanism or the like. Assist torque.

  The vehicle steering apparatus further includes a steering controller 30 that controls the steering angle ratio variable actuator 14 and the EPS actuator 24 based on input signals from various sensors. The steering controller 30 is a control device based on a well-known microcomputer, and includes a central processing unit (CPU) that executes a program, a memory that stores programs and various data, such as ROM and RAM, and an electrical signal. And an input / output (I / O) bus.

  As shown in FIG. 2, the steering controller 30 includes a rotation angle calculation unit 32, a motor control unit 33, and a vibration detection unit 34 as a functional configuration for controlling the steering angle ratio variable actuator 14. In addition, as a functional configuration for controlling the EPS actuator 24, an assist torque calculation unit 36 and a motor control unit 38 are included.

  Various information is input to the steering controller 30 from a plurality of sensors provided in the vehicle. Referring to FIG. 1, the steering angle sensor 26 detects the steering angle of the steering shaft 12, more specifically, the steering angle of the first shaft 11a. A torque sensor 27 for detecting the rotational torque (referred to as pinion torque) of the steering shaft 12 (second shaft 11b) in the vicinity of the pinion 18 and a vehicle speed sensor 28 for detecting the traveling speed of the vehicle. The signals from these sensors 26 to 28 are input to the steering controller 30 via an in-vehicle network such as a CAN (Controller Area Network).

  The rotation angle calculation unit 32 is based on the information from the steering angle sensor 26 (steering angle) and the information from the vehicle speed sensor 28 (vehicle speed), and the target amount of addition of the turning angle by the steering angle ratio variable actuator 14. A value is calculated.

  Here, the addition (adjustment) of the turning angle by the steering angle ratio variable actuator 14 will be described in detail. In this vehicle steering device, in order to improve the operability and running stability of the vehicle, the steered angle (STE steered wheel) of the steered wheels 22 based on the driver's operation of the steered wheels 10 according to the vehicle speed and the steering speed. Control for adding the turning angle (ACT angle θb) of the steered wheels 22 based on the driving of the motor 15b (steering angle ratio variable actuator 14) to the angle θa), that is, the steering angle ratio (steering angle / steering angle). The steering controller 30 executes control for changing the above.

  In this case, as shown in FIG. 3A, by adding the ACT turning angle θb in the same direction as the steering direction to the STE turning angle θa based on the operation of the steering wheel 10 (steering angle θs), Control that changes the ratio (steering angle ratio) of the turning angle θt of the steered wheels 22 to the steering angle θs of the steered wheels 10 is lead steer control. The lead steer control is mainly executed to improve vehicle operability at low and medium speeds.

  On the contrary, as shown in FIG. 3B, the ACT turning angle θb opposite to the steering direction is added to the STE turning angle θa, that is, the ACT turning angle θb is subtracted. By doing so, it is also possible to perform control to change the ratio (steering angle ratio) of the turning angle θt of the steered wheels 22 to the steering angle θs of the steered wheels 10. The lead steer control for reducing the rudder angle is mainly executed to prevent the vehicle behavior from shifting to an unstable region at a high speed.

  When the steered wheel 10 is operated, the rotation angle calculation unit 32 performs ACT steering to be added by the steering angle ratio variable actuator 14 based on information from the steering angle sensor 26 and the vehicle speed sensor 28 (vehicle speed and steering angle). A target value of the angle θb (target ACT turning angle θbt) is calculated, and the result is output to the motor control unit 33. Specifically, a steering speed (steering angular speed) is obtained by differentiating the steering angle, and based on the steering speed and the vehicle speed, a target ACT turning angle θbt is obtained from a predetermined map or the like, and its direction (+ / −), That is, whether to perform general lead steer control or lead steer control to reduce the steering angle is determined, and the result is output to the motor control unit 33.

  The motor control unit 33 outputs a control signal corresponding to the target ACT turning angle θbt based on the calculation result of the rotation angle calculating unit 32 (target ACT turning angle θbt), thereby the motor 15b (steering angle ratio). The variable actuator 14) is feedback-controlled.

  The vibration detection unit 34 calculates the steering speed and the steering acceleration (steering angular acceleration) based on the information (steering angle) from the steering angle sensor 26, the steering angle, the steering speed and the steering acceleration, and the information from the torque sensor 27. Based on (pinion torque), the following self-excited vibration of the steering wheel 10 is detected, and a signal is output to the rotation angle calculation unit 32 to stop the lead steer control. When there is a signal input from the vibration detection unit 34, the rotation angle calculation unit 32 executes a process of stopping the read steer control. Specifically, it is determined whether or not the current vehicle speed is a speed range in which lead steer control is executed (referred to as a lead steer control speed range), and the current vehicle speed corresponds to the lead steer control speed range. The target ACT turning angle θbt is set to “0”. This substantially stops the read steer control. Note that the steering acceleration is obtained by differentiating the steering speed obtained from the steering angle sensor 26 in the vibration detection unit 34. That is, in this example, the steering angle, the steering speed, and the steering acceleration correspond to the physical quantities of the present invention, and the steering angle sensor 26 and the vibration detection unit 34 correspond to the first detection means of the present invention. The torque sensor 27 corresponds to the second detection means of the present invention.

  The assist torque calculator 36 calculates a target assist torque by the EPS actuator 24 based on information (pinion torque) from the torque sensor 27 and information (vehicle speed) from the vehicle speed sensor 28, and the result is calculated by a motor controller. The motor control unit 38 feedback-controls the motor 25 (EPS actuator 24) by outputting a control signal corresponding to the target assist torque obtained by the assist torque calculation unit 36. .

  Next, the control of the steering controller 30 for stopping the lead steer control will be described in detail. Here, the necessity of stopping the lead steer control will be described before the specific control of the steering controller 30 is described.

  In the lead steer control, as described above, when the driver operates the steered wheel 10, the STE steered angle θa by the steering is added to the ACT steered angle θb in the same direction as the steered direction of the steered wheel 10. The steering angle ratio variable actuator 14 is based on the premise that the driver is holding the steered wheel 10, and the second shaft 11b is relative to the first shaft 11a by the ACT steering angle θb. To rotate. For this reason, when the driver performs a letting operation while the steered wheel 10 is in the cut-in steering state, that is, the steered wheel 10 is moved to the neutral (straight) position using the self-aligning torque (SAT) acting on the steered wheel 22. When a hand-off operation (including a state in which the hand is attached to the steered wheel 10 but is not substantially steered) is performed, the phenomenon that the steered wheel 10 vibrates in the rotational direction (self-excited vibration) occurs. Get up.

  The generation mechanism of this self-excited vibration will be described with reference to FIGS. For example, as shown in FIG. 6A, when the driver cuts and steers the steering wheel 10 to the right during low speed traveling and then releases the hand from the steering wheel 10 (at time t11 in FIG. 7), the steered wheel 22 S. acting on A. Due to T, as shown in FIG. 6B, the steering wheel 10 (steering shaft 12) rotates counterclockwise toward the neutral position. When the steered wheel 10 rotates, the target ACT turning angle θb is obtained based on the input from the steering angle sensor 26, and the steered angle ratio variable actuator 14 is actuated as indicated by a broken line arrow in FIG. 6B. That is, the rudder angle ratio variable actuator 14 applies a counterclockwise driving force to the second shaft 11 b on the side opposite to the steered wheel 10 of the steering shaft 12. Therefore, as shown in FIG. 6C, the steering wheel 10 in the released state is returned in the reverse direction (clockwise) together with the first shaft 11a (mainly from the time t12 to the time t13 in FIG. 7). When the steered wheel 10 rotates clockwise as described above, the target ACT turning angle θb is obtained based on this rotation, and the steered angle ratio variable actuator 14 is operated as indicated by a broken line arrow in FIG. That is, this time, the steering angle ratio variable actuator 14 is operated so as to rotate the second shaft 11b clockwise, and as a result, the steering wheel 10 in the released state is returned counterclockwise (mainly in FIG. 7). t14 to t15). Thereafter, the steering wheel 10 is returned to the neutral position while the phenomenon that the rotation direction of the steering wheel 10 is switched in a short time is repeated. In short, this phenomenon is the above self-excited vibration.

  Such vibration of the steered wheels 10 may give the driver a sense of discomfort and anxiety, and needs to be resolved quickly.

  The vibration detection unit 34 outputs a stop signal to the rotation angle calculation unit 32 to stop the lead steer control based on detection of such self-excited vibration generated in the steering wheel 10.

  FIG. 4 is a flowchart illustrating an example of control executed by the vibration detection unit 34 in order to stop the lead steer control. This control starts, for example, when an IGN (ignition) switch of the vehicle is turned on.

  When this control is started, the vibration detector 34 starts reading signals from the steering angle sensor 26 and the torque sensor 27 (step S1), and first determines whether or not the steered wheel 10 is being switched back (step S1). S3 / corresponds to the switching back state detection step of the present invention).

  Specifically, based on the steering angle and the steering speed, the vibration detection unit 34 determines that the steered wheel 10 is turned back when these directions are different.

  For example, FIG. 5 shows the steering angle, steering speed, steering acceleration, and pinion torque when the steering wheel 10 is turned to the right from the neutral position and then turned back at the time t1 (when turned to the left). The broken line in the figure shows the change when the driver is still steering the steered wheel 10 after the turning steering, and the solid line is released by the driver after the turning steering. The change when driving is shown. As shown in the figure, when the steering wheel 10 is switched back, the steering wheel 10 is steered to the right from the neutral position, and the steering direction is leftward, so that the steering angle and the steering speed direction. Is different. This is because the S.I. A. The same applies to the case where the steered wheels 10 are turned back by T. Therefore, the vibration detector 34 determines whether or not the steered wheel 10 is being switched back by monitoring the steering angle and the steering speed in this way.

  If it is determined in step S3 that the steered wheel 10 is being switched back, the vibration detection unit 34 determines whether a twist relationship has occurred between the first shaft 11a and the second shaft 11b. (Step S5 / corresponds to the vibration detection step of the present invention). Specifically, the vibration detection unit 34 is based on the steering acceleration and the pinion torque, and when these directions are different, a twist relationship is generated between the first shaft 11a and the second shaft 11b. Then, it is determined that self-excited vibration has occurred in the steering wheel 10.

  More specifically, if the driver continues to steer the steered wheel 10 after the turning steering, as shown by the broken line in FIG. 5, the steered wheel 10 returns to the neutral position during the switchback period of the steered wheel 10 (see FIG. 5). The direction of the steering acceleration of the steered wheel 10 and the direction of the pinion torque applied to the second shaft 11b are the same. However, S. A. When the steered wheel 10 is switched back by T, a unique phenomenon as shown in FIG. 6C occurs after the start of switching back. Specifically, as described above, a counterclockwise driving force (rotational torque) is applied to the second shaft 11b by the steering angle ratio variable actuator 14, and the first shaft 11a is returned in the reverse direction (clockwise) accordingly. Phenomenon occurs. As a result, as shown at time t2 in FIG. 5, the direction of the steering acceleration of the first shaft 11a based on the input from the steering angle sensor 26 and the direction of the pinion torque of the second shaft 11b based on the input from the torque sensor 27 Is temporarily reversed. That is, a twisted relationship is generated between the first shaft 11a and the second shaft 11b.

  In step S5, the vibration detection unit 34 determines whether or not a torsional relationship has occurred between the first shaft 11a and the second shaft 11b. If it is determined that it has occurred, the vibration detection unit 34 stops the lead steer control. Is output to the rotation angle calculator 32 (step S7), and the control based on this flowchart is terminated. That is, the torsion between the first shaft 11a and the second shaft 11b is basically due to the first wave of the self-excited vibration, and the vibration detecting unit 34 detects the steering acceleration of the first shaft 11a and the second vibration. The twist is detected by monitoring the direction of the pinion torque of the two shafts 11b, thereby detecting the occurrence of self-excited vibration. Based on this detection, the stop signal is output to the rotation angle calculation unit 32 to stop the read steer control.

  The vehicular steering apparatus according to the present invention has been described above. According to such a vehicular steering apparatus, after the driver cuts and steers the steered wheel 10, the S.P. A. Even if a self-excited vibration is generated in the steering wheel 10 by releasing the hand to return the steering wheel 10 to the neutral position by using T, the lead steer control is immediately stopped. Therefore, the self-excited vibration is prevented from continuing for a long time until the steered wheel 10 returns to the neutral position.

  In particular, according to this vehicle steering apparatus, as described above, the lead steer control is stopped based on detection of the twist between the first shaft 11a and the second shaft 11b caused by the first wave of the self-excited vibration. In short, since the lead steer control is stopped based on detection of the first wave of the self-excited vibration, the self-excited vibration is generated but is eliminated very quickly. Therefore, the driver hardly feels the self-excited vibration, and the substantial generation of the self-excited vibration can be suppressed. Therefore, the driver is A. Even when the driver uses the T to release the steering wheel 10 to return it to the neutral position, the driver can be prevented from feeling uncomfortable or uneasy.

  Moreover, according to this vehicle steering apparatus, first, it is determined whether or not the steered wheel 10 is being switched back based on the directions of the steering angle and the steering speed of the steered wheel 10, and the steered wheel 10 is being switched back. In this case, it is further determined whether or not self-excited vibration has occurred based on the steering acceleration of the steering wheel 10 (first shaft 11a) and the direction of the torque of the pinion 18 (second shaft 11b). Therefore, the lead steer control can be stopped by detecting the occurrence of self-excited vibration with a very simple logic and with high accuracy. Therefore, there is an advantage that the control load of the steering controller 30 is light.

  Further, according to the vehicle steering apparatus, parameters (steering angle, steering speed, steering acceleration, pinion torque) necessary for detecting self-excited vibration are controlled by the steering angle ratio variable actuator 14 and the EPS actuator 24. Is obtained based on information from the steering angle sensor 26 and the torque sensor 27 used in the above. Therefore, there is an advantage that the occurrence of self-excited vibration can be detected with a rational configuration using information obtained from existing sensors (steering angle sensor 26 and torque sensor 27) mounted on the vehicle.

  The vehicle steering device described above is an exemplification of a preferred embodiment of the vehicle steering device of the present invention, and its specific configuration can be appropriately changed without departing from the gist of the present invention.

  Furthermore, even if the steered wheel has a non-circular shape having a pair of arc-shaped gripping portions used in recent years in sports cars or the like, it can be changed as appropriate without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Steering wheel 11a 1st shaft 11b 2nd shaft 12 Steering shaft 14 Steering angle ratio variable actuator (steering angle ratio variable means)
22 steered wheels 20 rack shaft (steering rack)
24 EPS actuator (power steering means)
26 Steering angle sensor (first detection means)
27 Torque sensor (second detection means)
28 Vehicle speed sensor 30 Steering controller (control means)
32 Rotation angle calculation unit 33, 38 Motor control unit 34 Vibration detection unit 36 Assist torque calculation unit

Claims (4)

A steering shaft having a first shaft connected to the steering wheel and rotating integrally with the steering wheel, and a second shaft having a pinion meshing with the steering rack;
By interposing between the first shaft and the second shaft and rotating the second shaft relative to the first shaft, the ratio of the turning angle of the steered wheel to the steering angle of the steered wheel is Rudder angle ratio variable means for changing a certain rudder angle ratio;
First detection means for detecting a physical quantity that changes as the steering wheel rotates and a direction of the change;
Second detection means for detecting a direction of torque applied to the first shaft;
A lead that changes the steering angle ratio by adding a turning angle in the same direction as the steering direction of the steered wheel to the steered angle of the steered wheel based on the operation of the steered wheel based on the detection result of the first and second detection means. Control means for controlling the steering angle ratio variable means to perform the steering operation and stop the steering operation,
The control means is configured such that, during execution of the lead steer operation, the steering wheel is in a state of switching back and the physical quantity is the direction of rotational angular acceleration of the steering wheel and the direction of torque applied to the second shaft. A steering apparatus for a vehicle, characterized in that said lead steer operation is stopped when a different state occurs. The vehicle steering apparatus according to claim 1,
The control means determines that the steered wheel is in a switchback state when the direction of the steering angle of the steered wheel that is the physical quantity is different from the direction of the rotational speed of the steered wheel that is the physical quantity. A vehicle steering apparatus characterized by that. The vehicle steering apparatus according to claim 1,
A power steering means further comprising: a torque sensor that detects a rotational torque of the first shaft; and an actuator that applies an assist torque to the steering rack according to a detected torque of the torque sensor accompanying an operation of a steered wheel,
The vehicle steering apparatus, wherein the second detection means is the torque sensor. A steering shaft having a first shaft connected to the steering wheel and rotating integrally with the steering wheel and a second shaft having a pinion meshing with the steering rack, and between the first shaft and the second shaft A steering angle ratio variable means for changing a steering angle ratio, which is a ratio of a turning angle of a steered wheel to a steering angle of the steered wheel, by intervening and rotating the second shaft relative to the first shaft; The steering in a vehicle that performs a lead steer operation in which the steering angle ratio is changed by adding a steering angle in the same direction as the steering direction of the steered wheel to the steered angle of the steered wheel based on the operation of the steered wheel A method for detecting self-excited vibration of a ring,
Based on the direction of the steering angle of the steered wheel and the direction of the rotational speed of the steered wheel, a switchback state detecting step for detecting that the steered wheel is in a switchback state, and the steering wheel is in a switchback state A vibration detecting step of detecting presence or absence of self-excited vibration based on the direction of rotational angular acceleration of the steered wheel and the direction of torque applied to the second shaft,
In the switchback state detection step, when the steering angle direction of the steered wheel is different from the rotation speed direction of the steered wheel, it is determined that the steered wheel is in a switchback state;
In the vibration detection step, it is determined that self-excited vibration is generated when the direction of rotational angular acceleration of the stearin is different from the direction of torque applied to the second shaft. Self-excited vibration detection method.

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