JP2013095365A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress degradation of operability, and controllability and stability even when a vehicular speed sensor fails.SOLUTION: This steering device 10 includes: a right-side steering input part 20R; a left-side steering input part 20L; a vehicular speed sensor 40; a turning mechanism 12 for turning a steering wheel RW in accordance with a steering angle of at least one of the right-side steering input part 20R and the left-side steering input part 20L; and a steering ECU 30 for setting a steering angle ratio being a ratio of a turning angle of the steering wheel to the steering angle of at least one of the right-side steering input part 20R and the left-side steering input part 20L based on the vehicular speed detected by the steering ECU 30. When the vehicular speed sensor 40 fails, the steering ECU 30 sets a first steering angle ratio being a ratio of the turning angle of the steering wheel RW to the steering angle of the right-side steering input part 20R, and a second steering angle ratio being a ratio of the turning angle of the steering wheel RW to the steering angle of the left-side steering input part 20L at values different from each other.

Description

  The present invention relates to a steering device provided in a vehicle.

  A steering wheel is generally used as a steering input means in a steering apparatus for a vehicle such as an automobile. For example, as disclosed in Patent Document 1, two joysticks provided on the left and right sides of a driver's seat are used as steering input means. A steering device is known.

  In a joystick-type steering device, the ratio of the steering angle of the steered wheel to the steering angle of the joystick (hereinafter referred to as “steering angle ratio”) is much larger than that of the steering wheel. There is a problem that a driver accustomed to steering feels a sense of incongruity and poor operability, and the steering stability of the vehicle is likely to deteriorate due to excessive steering wheel breakage.

  Therefore, the steering device disclosed in Patent Document 1 is configured such that the steering angle ratio decreases as the vehicle speed detected by the vehicle speed sensor increases. As a result, while maintaining good steering sensitivity in the low vehicle speed range, it is possible to reduce the steering sensitivity in the high vehicle speed range to prevent the steering wheel from being cut too much and perform delicate steering. In addition, it is possible to improve the steering stability of the vehicle when traveling at high speed.

Japanese Patent Laid-Open No. 8-34353

  However, in the steering device disclosed in Patent Document 1, when the vehicle speed sensor fails, the steering angle ratio cannot be changed based on the vehicle speed, and operability and steering stability may be reduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a steering apparatus that can suppress a decrease in operability and steering stability even when a vehicle speed sensor fails. is there.

  In order to solve the above problems, a steering device according to an aspect of the present invention includes a first steering input unit, a second steering input unit, a vehicle speed sensor, at least one of a first steering input unit and a second steering input unit. A steering mechanism that steers the steering wheel according to the steering angle of the vehicle, and the turning of the steering wheel with respect to at least one steering angle of the first steering input unit and the second steering input unit based on the vehicle speed detected by the vehicle speed sensor. A setting unit that sets a rudder angle ratio that is a ratio of rudder angles. When the vehicle speed sensor fails, the setting unit is configured to rotate the steering wheel with respect to the first steering angle ratio, which is a ratio of the steering angle of the steering wheel to the steering angle of the first steering input unit, and the steering angle of the second steering input unit. The second steering angle ratio, which is the ratio of the steering angles, is set to a different value.

  When the vehicle speed sensor fails, the setting unit sets the first steering angle ratio to a predetermined high vehicle speed steering angle ratio, and sets the second steering angle ratio to a low vehicle speed steering angle ratio that is higher than the high vehicle speed steering angle ratio. May be set.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a vehicle speed sensor fails, the steering device which can suppress the fall of operativity and steering stability can be provided.

FIGS. 1A to 1C are diagrams showing a vehicle to which the steering device according to this embodiment can be applied. It is a schematic plan view for demonstrating the structure of the steering device which concerns on this embodiment. It is a schematic side view for demonstrating the structure of the steering device which concerns on this embodiment. It is a flowchart for demonstrating operation | movement of the steering device which concerns on this embodiment.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  1A to 1C show a vehicle to which the steering device according to the present embodiment can be applied.

  A vehicle 1 shown in FIG. 1A is a vehicle in which the front wheel FW and the rear wheel RW are located on a front-rear line passing through the center between the right wheel RSW and the left wheel LSW. In the vehicle 1, the front wheel FW is a steering wheel.

  A vehicle 2 shown in FIG. 1B is a vehicle that includes two wheels, a right wheel RSW and a left wheel LSW, at the front of the vehicle and one rear wheel RW at the rear of the vehicle. In the vehicle 2, the rear wheel RW is a steering wheel.

  A vehicle 3 shown in FIG. 1C is a vehicle that includes two wheels, a right front wheel FRW and a left front wheel FLW, in front of the vehicle and two wheels, a right rear wheel RRW and a left rear wheel RLW, in the rear of the vehicle. In the vehicle 3, the right front wheel FRW and the left front wheel FLW are often used as steering wheels.

  Below, the case where the steering apparatus which concerns on this embodiment is applied to the vehicle 2 shown in FIG.1 (b) is demonstrated. The steering apparatus according to the present embodiment is a steer-by-wire steering apparatus that electrically performs a steering operation.

  FIG. 2 is a schematic plan view for explaining the configuration of the steering device 10 according to the present embodiment. FIG. 3 is a schematic side view for explaining the configuration of the steering device 10 according to the present embodiment.

  As shown in FIGS. 2 and 3, the steering device 10 includes a steering mechanism 12 for turning a rear wheel RW (hereinafter referred to as “steered wheel RW”), and a driver's seat (not shown) of the vehicle. Steering based on the right steering input unit 20R and the left steering input unit 20L provided on both sides of the vehicle, the vehicle speed sensor 40 for detecting the vehicle speed of the vehicle, the operation amount of the right steering input unit 20R, the left steering input unit 20L, and the vehicle speed. And a steering ECU 30 that controls the turning angle of the wheel RW.

  The steered mechanism 12 includes a support member 15 that supports the steered wheels RW, a kingpin shaft 16 that is fixed to the support member 15, a steered motor 17, and a driving force from the steered motor 17. And a turning angle sensor 19 for detecting the rotation angle of the kingpin shaft, that is, the turning angle of the steered wheel RW.

  The right steering input unit 20R and the left steering input unit 20L respectively control the operation levers 21R and 21L, the lever holding units 22R and 22L that rotatably hold the operation levers 21R and 21L, and the rotation angles of the operation levers 21R and 21L. Steering angle sensors 23R and 23L to be detected, and motors 27R and 27L for rotating the operation levers 21R and 21L are provided.

  The operation levers 21R and 21L are generally L-shaped, and have rotation shafts 24R and 24L and operation shafts 25R and 25L orthogonal to the rotation shafts 24R and 24L, respectively. Grips 26R and 26L are provided at the distal ends of the operation shafts 25R and 25L, respectively. The operation levers 21R and 21L are held by the lever holding portions 22R and 22L so as to be rotatable around the axis S in a posture in which the rotary shafts 24R and 24L extend in the front-rear direction of the vehicle. The rotary shafts 24R and 24L are connected to the motors 27R and 27L, and can be rotated by a command from the steering ECU 30.

  The driver holds the grip 26R with the right hand and the grip 26L with the left hand, and rotates the operation levers 21R and 21L around the axis S. The position where the operation shafts 25R, 25L provided with the grips 26R, 26L extend in the vertical direction of the vehicle is the neutral position. In a state where the operation levers 21R and 21L are in the neutral position, the vehicle is in a straight traveling state, and the turning angle of the steered wheels RW becomes 0 degrees.

  The steering ECU 30 detects the steering angle of the operation levers 21R, 21L detected by the steering angle sensors 23R, 23L, the turning angle of the steered wheels RW detected by the turning angle sensor 19, and the vehicle speed sensor 40. The vehicle speed is input.

  During normal times, the steering ECU 30 sets the ratio of the steered angle of the steered wheels RW to the steered angles of the right steering input unit 20R and the left steering input unit 20L (steering angle ratio) based on the input vehicle speed. Specifically, the steering ECU 30 sets the steering angle ratio to be smaller as the vehicle speed is higher. Thereby, in the low speed region, the steered wheels RW can be quickly steered from the moment when the right steering input unit 20R and the left steering input unit 20L are started to be operated, and the operability can be improved. In addition, since the operation sensitivity of the right steering input unit 20R and the left steering input unit 20L is reduced in the high speed range, the steering wheel RW is prevented from being excessively cut, and the operability and steering stability can be improved.

  The steering device 10 according to the present embodiment is configured such that the steered wheels RW are steered when at least one of the right steering input unit 20R and the left steering input unit 20L is operated. Here, a case where the right steering input unit 20R is operated will be described as an example.

  When the right steering input unit 20R is operated by the driver, the steering angle θ1 is detected by the steering angle sensor 23R. The detected steering angle θ1 is sent to the steering ECU 30. The steering ECU 30 determines a target turning angle δ * based on the input steering angle θ1 and the set steering angle ratio R, and drives the steering motor 17 to drive the steering wheel to the target turning angle δ *. Steer RW. When the steered wheel RW is steered, feedback control using the actual steered angle δ detected by the steered angle sensor 19 is performed.

  Simultaneously with the steering wheel RW being steered, the steering ECU 30 may control the motor 27L so that the steering angle θ2 of the left steering input portion 20L is the same as the steering angle θ1. Thereby, the operating lever 21L moves in the same manner as the operating lever 21R. When the operation lever 21L is moved, feedback control is performed using a value detected by the steering angle sensor 23L.

  The operation when the right steering input unit 20R is operated has been described above, but the same operation is performed when the left steering input unit 20L is operated.

  Next, the operation when the vehicle speed sensor 40 fails will be described. When the vehicle speed sensor 40 fails, the steering ECU 30 cannot acquire the vehicle speed information, and thus cannot set the steering angle ratio based on the vehicle speed as in normal times. In this case, a method of appropriately determining a provisional vehicle speed and setting the steering angle ratio based on the vehicle speed is conceivable. However, in such a method, for example, when the set temporary vehicle speed is high but the actual vehicle speed is low, the operation sensitivity of the steering input unit is low and the operability is deteriorated. For example, when the set temporary vehicle speed is low but the actual vehicle speed is high, the operation sensitivity of the steering input unit is high, and the operability and steering stability are deteriorated.

  Therefore, in the steering apparatus 10 according to the present embodiment, the steering ECU 30 is the first rudder that is the ratio of the turning angle δ of the steered wheels RW to the steering angle θ1 of the right steering input portion 20R when the vehicle speed sensor 40 fails. The angle ratio R1 and the second steering angle ratio R2 that is the ratio of the turning angle δ of the steered wheels RW to the steering angle θ2 of the left steering input portion 20L are set to different values.

  For example, the steering ECU 30 sets the first steering angle ratio R1 of the right steering input unit 20R to a predetermined high vehicle speed steering angle ratio RH, and sets the second steering angle ratio R2 of the left steering input unit 20L to the high vehicle speed steering angle. A low vehicle speed steering angle ratio RL higher than the ratio RH is set.

  The high vehicle speed steering angle ratio RH is a steering angle ratio suitable for high-speed traveling (for example, 60 km / h or more), and is a steering angle ratio lower than a standard steering angle ratio. Here, the standard rudder angle ratio is a rudder angle ratio set when the vehicle has an average vehicle speed (for example, 40 km / h).

  The low vehicle speed steering angle ratio RL is a steering angle ratio suitable for low speed traveling (for example, 20 km / less), and is a steering angle ratio higher than the standard steering angle ratio.

  The appropriate values for the high vehicle speed steering angle ratio RH and the low vehicle speed steering angle ratio RL vary depending on the type of vehicle and the like, and may be set as appropriate through experiments and simulations.

  When the first steering angle ratio R1 of the right steering input unit 20R and the second steering angle ratio R2 of the left steering input unit 20L are set as described above, the driver can operate the two left and right operation input units according to the speed of the vehicle. You can select and operate the appropriate one.

  For example, when the vehicle is traveling at a high speed, the driver operates the right steering input unit 20R with the right hand. Thereby, for example, even when the vehicle speed sensor 40 fails during traveling, it is possible to prevent or at least alleviate deterioration in operability and steering stability.

  On the other hand, when the vehicle is traveling at a low speed, the driver operates the left steering input unit 20L with the left hand. Thereby, for example, even when the vehicle speed sensor 40 fails during traveling, a decrease in operability can be prevented or at least mitigated.

  Of course, regarding the left and right steering input units, the setting of the steering angle ratio RH at the high vehicle speed and the steering angle ratio RL at the low vehicle speed may be reversed. That is, the first steering angle ratio R1 of the right steering input unit 20R is set to the low vehicle speed steering angle ratio RL, and the second steering angle ratio R2 of the left steering input unit 20L is set to the high vehicle speed steering angle ratio RH. Also good.

  At the same time when the steering wheel RW is steered, the steering ECU 30 may control the motor so that the steering angle of the steering input unit that is not operated becomes the same as the steering angle of the operated steering input unit. .

  FIG. 4 is a flowchart for explaining the operation of the steering apparatus 10 according to the present embodiment. The control flow shown in FIG. 4 is executed at predetermined time intervals.

  First, the steering ECU 30 determines whether or not the vehicle speed sensor 40 is normal (S10).

  When the speed sensor is normal (Y in S10), the steering ECU 30 receives vehicle speed information from the speed sensor (S12).

  Next, the steering ECU 30 sets the steering angle ratio R according to the vehicle speed (S14). Specifically, the steering angle ratio R is set to be smaller as the vehicle speed is higher.

  Next, the steering ECU 30 determines whether one of the right steering input unit 20R and the left steering input unit 20L has been operated (S16). This determination can be made by looking at changes in the steering angle received from the right steering input unit 20R and the left steering input unit 20L. If it is not operated (N in S16), it waits for execution of the operation.

  When one of the right steering input unit 20R and the left steering input unit 20L is operated (Y in S16), the steering ECU 30 performs steering control of the steered wheels RW at the steering angle ratio R set in S14 (S18). ), And ends the control flow.

  On the other hand, when the vehicle speed sensor 40 has failed (N in S10), the steering ECU 30 sets the first steering angle ratio R1 of the right steering input unit 20R to the high vehicle speed steering angle ratio RH, and the left steering input unit 20L. The second steering angle ratio R2 is set to the low vehicle speed steering angle ratio RL (S20). Here, the high vehicle speed steering angle ratio RH <the low vehicle speed steering angle ratio RL.

  Next, the steering ECU 30 determines whether or not the right steering input unit 20R has been operated (S22).

  When the right steering input unit 20R is operated (Y in S22), the steering ECU 30 performs the steering control of the steered wheels RW at the first steering angle ratio R1 set to the high vehicle speed steering angle ratio RH (S24). The control flow is terminated.

  When the right steering input unit 20R is not operated (N in S22), the steering ECU 30 determines whether or not the left steering input unit 20L is operated (S26). When the left steering input unit 20L is not operated (N in S26), the process returns to S22 and waits for the operation of the steering input unit.

  When the left steering input unit 20L is operated (Y in S26), the steering ECU 30 performs the steering control of the steered wheels RW at the second steering angle ratio R2 set to RL as the steering angle at the low vehicle speed (S28). The control flow is terminated.

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Steering device, 12 Steering mechanism, 16 King pin shaft, 17 Steering motor, 19 Steering angle sensor, 20R Right steering input part, 20L Left steering input part, 30 Steering ECU, 40 Vehicle speed sensor

Claims (2)

A first steering input unit;
A second steering input unit;
A vehicle speed sensor,
A steering mechanism that steers a steered wheel according to a steering angle of at least one of the first steering input unit and the second steering input unit;
A setting unit that sets a steering angle ratio that is a ratio of a steering angle of a steered wheel to a steering angle of at least one of the first steering input unit and the second steering input unit based on the vehicle speed detected by the vehicle speed sensor. And comprising
When the vehicle speed sensor fails, the setting unit has a first steering angle ratio that is a ratio of a steering angle of a steered wheel to a steering angle of the first steering input unit, and a steering angle of the second steering input unit. A steering apparatus, wherein a second steering angle ratio, which is a ratio of steering angles of steered wheels, is set to a different value.   When the vehicle speed sensor fails, the setting unit sets the first steering angle ratio to a predetermined high vehicle speed steering angle ratio, and the second steering angle ratio is lower than the high vehicle speed steering angle ratio. The steering device according to claim 1, wherein the steering angle ratio is set to a vehicle speed steering angle ratio.

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