Vehicle steering control device

Abstract

To provide a vehicle steering control device that can prevent a driver from starting to drive the vehicle without being able to steer it correctly when the power supply of the vehicle is turned on.SOLUTION: A vehicle fixation control unit 52 fixes a vehicle 10 while an operating wheel ECU 42 and a steerable wheel ECU 44 are correcting the steering angle θw of steerable wheels 32 to the target steering angle θt based on the steering angle θs of a steering wheel 22, and does not release the vehicle fixation by a vehicle fixing device 60 until the steering angle correction is complete, regardless of a vehicle fixation release request made by operation of a vehicle fixing device release operation switch 62. This makes it possible to prevent the driver from starting to drive the vehicle 10 without being able to steer it correctly when the power supply of the vehicle 10 is turned on.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a steer-by-wire type vehicle steering control device. [Background technology]

[0002] Steer-by-wire vehicle steering control devices are known in which the steering wheel and the steered wheels are mechanically separated and the steering angle of the steered wheels is changed by controlling a steering angle motor in accordance with the steering angle of the steering wheel. For example, the steering control device described in Patent Document 1 is one such device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-131351 Summary of the Invention [Problem to be solved by the invention]

[0004] A steer-by-wire vehicle steering control device controls the steering angle to track the steering wheel angle via communication of control signals, control information, and the like between a steering wheel control device and a steered wheel control device. That is, the steering wheel and the steered wheels are electrically connected and operate. However, when the vehicle power is turned off, the electrical connection is released. Therefore, if the steering wheel is turned while the power is off, the tracking between the steering angle and the steering wheel angle will be out of sync. Therefore, when the vehicle power is turned on, control is performed to correct the steering angle to an angle corresponding to the steering angle (steering angle correction). However, if the driver starts driving before the steering angle correction is complete, there is a risk that the driver will not be able to steer accurately and will lose control of the vehicle.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle steering control device that can prevent the driver from starting to drive without being able to steer accurately when the vehicle is turned on. [Means for solving the problem]

[0006] The gist of the present invention is (a) a steering control device for a vehicle in which a steering wheel and steerable wheels are mechanically separated, the steering angle of the steerable wheels is changed by controlling a steering angle motor in accordance with the steering angle of the steering wheel, and when the power of the vehicle is turned on, a steering angle correction is performed to correct the steering angle to an angle in accordance with the steering angle, and (b) a vehicle fixation control unit is provided which fixes the vehicle during the steering angle correction and does not release the fixation of the vehicle until the steering angle correction is completed, regardless of a vehicle fixation release request. [Effects of the Invention]

[0007] According to the vehicle steering control device of the present invention, the vehicle is fixed by the vehicle fixation control unit during the steering angle correction, and the fixation of the vehicle is not released until the steering angle correction is completed, regardless of a vehicle fixation release request. This makes it possible to prevent the driver from starting to drive without being able to steer accurately when the vehicle is powered on. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a vehicle steering control device to which the present invention is applied; [Figure 2] 2 is a time chart illustrating the main control operations of the vehicle steering control device of FIG. 1. [Figure 3] 2 is a flowchart illustrating a main part of the control operation of the vehicle steering control device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] 1, a vehicle 10 includes a steering mechanism 20 and a turning mechanism 30. The steering mechanism 20 and the turning mechanism 30 are mechanically separated from each other, and constitute a so-called steer-by-wire type steering device.

[0011] The steering mechanism 20 includes a steering wheel 22, a reaction force motor 24 that generates a steering reaction force on the steering wheel 22, and an operation angle sensor 26 that detects the steering angle θs of the steering wheel 22. A control signal to the reaction force motor 24 and a detection signal from the operation angle sensor 26 are connected to an operation wheel ECU 42, which will be described later.

[0012] The steering mechanism 30 includes a pair of steerable wheels 32 (for example, front wheels), a steering angle motor 34 that changes the steering angle θw of the steerable wheels 32, and a steering angle sensor 36 that detects the steering angle θw of the steerable wheels 32. A control signal to the steering angle motor 34 and a detection signal from the steering angle sensor 36 are connected to a steerable wheel ECU 44, which will be described later.

[0013] The vehicle 10 is equipped with a vehicle steering control device (hereinafter referred to as the steering control device) 40. The steering control device 40 is also equipped with an operating wheel ECU 42, a steered wheel ECU 44, and an electronic control device 50.

[0014] The controlled wheel ECU 42 and the steered wheel ECU 44 perform steer-by-wire control to change the steering angle θw of the steered wheels 32 in accordance with the steering angle θs resulting from the steering operation of the steering wheel 22. The controlled wheel ECU 42 and the steered wheel ECU 44 are connected via a communication line 46 so as to be able to communicate signals with each other.

[0015] The operating wheel ECU 42 and the steerable wheel ECU 44 determine a target steering angle θt, which is an angle based on the steering angle θs of the steering wheel 22, from a preset relationship based on the rotation ratio when the steering wheel 22 and the steerable wheels 32 are mechanically linked, and drive the steering angle motor 34 to control the steering angle θw of the steerable wheels 32 so that the steering angle θw of the steerable wheels 32 follows the target steering angle θt, while controlling the reaction force motor 24 so as to apply to the steering wheel 22 a reaction force according to the road surface conditions, vehicle speed, and steering angle θw (resting angle) of the steerable wheels 32. The operating wheel ECU 42 and the steerable wheel ECU 44 do not necessarily have to be configured as separate entities, and may be configured as a single computer.

[0016] Furthermore, when the vehicle 10 is powered on, the operating wheel ECU 42 and the steerable wheel ECU 44 drive the steering angle motor 34 to control the steering angle θw of the steerable wheel 32 so that the steering angle θw of the steerable wheel 32 becomes the target steering angle θt. This is because, if the steering wheel 22 is turned while the power is off, the tracking ability between the steering angle θs and the steering angle θw becomes misaligned. This correction of the steering angle θw when the power is turned on is referred to as "steering angle correction" in this embodiment. When the steering angle correction is completed, the operating wheel ECU 42 and the steerable wheel ECU 44 transmit a steering angle correction completion signal Ce to the electronic control device 50. While FIG. 1 shows the steerable wheel ECU 44 transmitting the steering angle correction completion signal Ce, the signal may be transmitted from the operating wheel ECU 42, or a notification of the completion of the steering angle correction may be transmitted via a communication network within the vehicle 10.

[0017] The vehicle 10 is equipped with a vehicle immobilization device 60 that prevents rotation of the pair of steered wheels 32 and a pair of rear wheels (not shown) in accordance with commands from the electronic control device 50, thereby immobilizing the vehicle 10. The vehicle immobilization device 60 is configured, for example, with any one of a parking lock mechanism, a parking brake, an electric brake, a hydraulic brake, a shift system control, etc.

[0018] The electronic control device 50 is configured by, for example, a microcomputer, and controls the vehicle immobilization device 60 in accordance with a pre-stored program. The electronic control device 50 functionally includes a vehicle immobilization control section 52.

[0019] The vehicle fixation control unit 52 normally fixes the vehicle by the vehicle fixation device 60 and releases it from vehicle fixation in response to a release operation of the vehicle fixation device release operation switch 62. However, when the steering angle is being corrected, that is, until the steering angle correction completion signal Ce is transmitted from the turnable wheel ECU 44, the vehicle fixation control unit 52 continues to fix the vehicle 10 even if a release operation is performed to release the vehicle 10 from the fixed state by operating the vehicle fixation device release operation switch 62. When the steering angle correction completion signal Ce is transmitted from the turnable wheel ECU 44, the vehicle fixation control unit 52 releases the vehicle fixation by the vehicle fixation device 60 in response to an operation to release the fixation of the vehicle 10.

[0020] In vehicle 10, which is equipped as a shift operation device with a momentary shifter having an automatic return shift lever that automatically returns from D position, R position, or N position to H position (home position) and a P push button switch corresponding to vehicle fixation device release operation switch 62, when the steering angle is being corrected in the parking lock state, vehicle fixation control unit 52 does not accept an operation to release the parking lock using the P push button switch, or an operation to a traveling position (D position or R position where driving force is output) using the automatic return shift lever corresponding to vehicle fixation device release operation switch 62 when the power is on (powered on) in the N position.

[0021] Furthermore, in vehicle 10 equipped with a mechanical lever shifter as a shift operation device, which has a shift lever that is operated sequentially to P position, R position, N position, and D position, when the steering angle is being corrected in the parking lock state, vehicle fixation control unit 52 locks the shift lever with an electric lock pin so that the shift lever corresponding to vehicle fixation device release operation switch 62 does not move from the P position or the N position. Furthermore, while the shift lever itself can be operated during steering angle correction, vehicle fixation control unit 52 disables operation of the shift lever to a driving position (D position or R position where driving force is output)

[0022] In addition, in a vehicle 10 equipped with an electric parking brake, the vehicle fixing control unit 52 does not accept an operation to release the electric parking brake using the vehicle fixing device release operation switch 62 when the electric parking brake is in an activated state and a steering angle correction is being performed.

[0023] In addition, in a vehicle 10 equipped with a manual parking brake, when the manual parking brake is activated and a steering angle correction is being performed, the vehicle fixing control unit 52 locks the manual parking brake with an electric lock pin to prevent it from moving to the unlocking side, thereby disabling the release operation of the manual parking brake.

[0024] Furthermore, in the vehicle 10 equipped with a hydraulic brake that brakes the rotation of the wheels using brake hydraulic pressure generated by operating the brake pedal, when the hydraulic brake is in operation and the steering angle is being corrected, the vehicle fixation control unit 52 executes control to maintain the brake hydraulic pressure so that the hydraulic brake is not released even if the brake pedal corresponding to the vehicle fixation device release operation switch 62 is released.

[0025] Fig. 2 is a time chart explaining the main parts of the control operation of the electronic control device 50 provided in the steering control device 40. Fig. 3 is a flowchart explaining the main parts of the control operation of the electronic control device 50 provided in the steering control device 40. Hereinafter, the control operation of the electronic control device 50 will be explained in accordance with the processing steps of Fig. 3 and with reference to Fig. 2.

[0026] First, in step S1 (hereinafter, "step" will be omitted) in Fig. 3, it is determined whether or not a power-on (power ON) operation has been performed when starting the system while the vehicle 10 is fixed (stopped) by the vehicle fixing device 60 (see time t1 in Fig. 2). If the determination in S1 is negative, the routine is terminated, but if the determination is positive, in S2, even if a release operation is performed to release the vehicle 10 from the fixed state by operating the vehicle fixing device release operation switch 62, the release of the vehicle fixing device 60 is prohibited, and the fixing of the vehicle 10 continues. In Fig. 2, this state is shown from time t1 to time t2.

[0027] In S3, it is determined whether the steering angle correction is completed. This determination is made based on whether the steering angle correction completion signal Ce is transmitted from the steered wheel ECU 44. If the determination in S3 is negative, the execution of S3 is repeated. However, if the determination in S3 is positive, in S4, the release of vehicle fixation by the vehicle fixation device 60 is permitted. If the vehicle fixation device release operation switch 62 is released, the vehicle fixation by the vehicle fixation device 60 is released, and this routine is terminated (see time t2 in FIG. 2).

[0028] As described above, according to the vehicle steering control device 40 of this embodiment, the vehicle 10 is fixed by the vehicle fixation control unit 52 during the steering angle correction, and the vehicle fixation by the vehicle fixation device 60 is not released until the steering angle correction is completed, regardless of a request to release the vehicle fixation by operating the vehicle fixation device release operation switch 62. This makes it possible to prevent the driver from starting to drive the vehicle 10 without being able to steer accurately when the power to the vehicle 10 is turned on.

[0029] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0030] For example, the steering control device 40 in the above-described embodiment was composed of the operating wheel ECU 42, the steered wheel ECU 44, and the electronic control device 50, but these do not necessarily have to be composed separately, and may be composed as control units for each device within a single computer.

[0031] For example, the vehicle 10 in the above-described embodiment may be any of a vehicle equipped with an engine as a power source, a BEV vehicle equipped with an electric motor as a power source, an HEV vehicle equipped with an engine and an electric motor as power sources, a PHEV vehicle, an FCEV vehicle, etc.

[0032] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0033] 10: vehicle, 22: steering wheel, 32: steered wheels, 34: steering angle motor, 40: steering control device (vehicle steering control device), 52: vehicle fixed control unit, θs: steering angle, θw: steering angle

Claims

[Claim 1] The steering wheel and the steered wheels are mechanically separated, and the steering angle of the steered wheels is changed by controlling a steering angle motor in accordance with the steering angle of the steering wheel, A steering control device for a vehicle, which performs a steering angle correction to correct the steering angle to an angle corresponding to the steering angle when a power source of the vehicle is turned on, a vehicle fixation control unit that fixes the vehicle during the steering angle correction and does not release the fixation of the vehicle until the steering angle correction is completed, regardless of a vehicle fixation release request; A vehicle steering control device characterized by:

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