Vehicle control method

Abstract

To adjust a speed at the time of ultra-pivotal brake turn by change of the angle of a wheel.SOLUTION: A control method of a vehicle performing ultra-pivotal brake turn includes the steps of: performing ultra-pivotal brake turn in a state in which the angle of a wheel 11 is set at a first angle; and changing the angle of the wheel 11 to a second angle in which the resistance of the wheel 11 increases when the ultra-pivotal brake turn is performed compared to the state of the first angle, when the speed of the ultra-pivotal brake turn increases and reaches a predetermined speed. Thereby, when the speed of the ultra-pivotal brake turn reaches predetermined speed, the rise of the speed can be suppressed by changing the angle of the wheel to a non-optimal angle from an angle optimal for the ultra-pivotal brake turn.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vehicle control method.

Background Art

[0002] In recent years, vehicles that can perform highly maneuverable turning around the center of the vehicle body, having four independently steerable wheels and in-wheel motors, have been used. Patent Document 1 discloses the relationship between the movement of the steering during highly maneuverable turning and the braking command, and it is described that braking is applied when the steering is at 0°.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a vehicle that performs highly maneuverable turning, centrifugal force acts as the rotational speed increases. Therefore, when the driver adjusts the rotational speed of highly maneuverable turning by pedal operation or steering operation, the rotational speed may increase more than expected due to the influence of centrifugal force. In this case, the driver tends to hurriedly step on the brake pedal, and when the braking force is large, the shock and shaking on the reverse rotation side become large. Therefore, there has been a desire to facilitate the speed adjustment by the driver's operation of the brake pedal by adjusting the speed by changing the angle of the wheels when performing highly maneuverable turning.

[0005] The present disclosure provides a vehicle control method for adjusting the speed during highly maneuverable turning by changing the angle of the wheels.

Means for Solving the Problems

[0006] The vehicle control method according to the present disclosure includes a step of performing a super-creditable turn with the wheel angle in a first angle state, and when the speed of the super-creditable turn increases and reaches a predetermined speed, changing the wheel angle to a second angle at which the resistance of the wheel during the super-creditable turn increases compared to the state of the first angle. Thereby, when the speed of the super-creditable turn reaches a predetermined speed, by changing the wheel angle from an angle suitable for the super-creditable turn to an unsuitable angle, an increase in speed can be suppressed.

Effects of the Invention

[0007] According to the present disclosure, it is possible to provide a vehicle control method for adjusting the speed during a super-creditable turn by changing the wheel angle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Embodiment 1 Hereinafter, the vehicle control method according to the present embodiment will be described with reference to the drawings. FIGS. 1(a) to 1(e) are schematic views showing the state in which the vehicle 1 performs a super-creditable turn from an overhead perspective.

[0010] FIG. 1(a) is a diagram showing an example of the configuration of the vehicle 1. The vehicle 1 includes wheels 11, a driving force generation unit 12, a steering unit 13, a brake system 14, and a control unit 15. FIGS. 1(b) to 1(e) are diagrams of the vehicle 1 showing the state of the super-creditable turn of the vehicle 1, but for the sake of clarity of the drawings, the description of some component articles such as the driving force generation unit 12 is omitted.

[0011] Vehicle 1 is a vehicle having four wheels 11, and will be described as being capable of independently controlling each of the four wheels.

[0012] An accelerator pedal and a brake pedal are provided at the driver's feet in vehicle 1. In vehicle 1, the driver can increase the rotational speed of the wheels 11 by stepping on the accelerator pedal, and can decrease the rotational speed of the wheels 11 by stepping on the brake pedal.

[0013] As shown in Fig. 1(a), the wheels 11 are provided at four locations on the front left side, front right side, rear left side, and rear right side of vehicle 1. Here, the state where the rotation axis extends in a direction parallel to the left-right direction of the vehicle body is set as θ = 0°. That is, in normal operation, vehicle 1 can travel forward with each of the four wheels 11 in the state of θ = 0°. Here, the wheels 11 are tires.

[0014] Fig. 1(b) is an example of the initial state in which the direction of the wheels 11 is changed when vehicle 1 performs a super-low-speed turn. As shown in Fig. 1(b), the wheels 11 can be set to an appropriate angle (θ1) for performing a super-low-speed turn, with the front wheels on the toe-in side and the rear wheels on the toe-out side, in response to the operation of the steering unit 13 by the driver. Here, θ1 is defined as the first angle. In vehicle 1, in the state where the direction of the wheels 11 is changed in this way, vehicle 1 can perform a super-low-speed turn by rotating the wheels 11 provided on the left side and the right side of vehicle 1 in opposite directions, respectively. For example, θ1 is 45°.

[0015] The driving force generation unit 12 is a motor that generates a driving force for independently changing the rotational direction and rotational speed of each wheel 11. Typically, an in-wheel motor (IWM) can be used for the driving force generation unit 12. Also, as shown in Fig. 1(a), the driving force generation unit 12 is provided for each of the wheels 11.

[0016] The steering unit 13 is a steering unit that can be operated by the driver. For example, the angle of each wheel 11 can be changed according to the movement and angle change of the steering.

[0017] The brake system 14 has a sensor that senses the brake pedal input, such as a pedal switch, the amount of pedal stroke, or the amount of depression force, for the brake pedal that can be operated by the driver, and can output the sensor value to the control unit 15.

[0018] The control unit 15 is a control unit that comprehensively controls each of the wheels 11, the driving force generation unit 12, the steering unit 13, and the brake system 14, and is typically an ECU (Electronic Control Unit) is. Here, for example, the vehicle 1 has an operation screen, buttons, levers, a steering wheel, switches, etc. that can be operated by the driver, and the control unit 15 controls the vehicle 1 to perform a predetermined operation according to these operations of the driver.

[0019] The control unit 15 also controls the angle of each wheel 11 and the vehicle body speed according to the operation amount of the steering unit 13 by the driver and inputs such as the accelerator pedal and the brake pedal. Note that the control unit 15 is assumed to acquire the speed of the vehicle 1 during extremely sharp turning.

[0020] Also, as will be described later, when the speed of the vehicle 1 reaches a predetermined speed while performing an extremely sharp turn, the control unit 15 can perform control to automatically change the angle of the wheel 11 from the angle θ1 to the angle θ2. For example, θ2 is 30°.

[0021] Next, a control method for the vehicle 1 will be described with reference to FIGS. 1(b) to 1(e), FIG. 2, and FIG. 3. In the following description of the operations, although the driving force generated by the driving force generation unit 12 is transmitted to the operations of the wheels 11, etc., for the sake of easier understanding, the description of the transmission of the driving force by the driving force generation unit 12 will be omitted. Here, FIGS. 1(b) to 1(e) are diagrams showing the states of the vehicle 1 performing a super-low-speed turn, FIG. 2 is a diagram showing the flow of the process related to the control of the vehicle, and each step of FIG. 2 will be described below.

[0022] Also, FIG. 3 is a diagram showing the change in the turning speed and the change in the angle of the wheels 11 when performing a super-low-speed turn controlled by the control unit 15. Here, the angle of the wheels 11 in FIG. 3 refers to the angle of one of the four wheels 11, and for any of the wheels 11, the front wheels are in the toe-in direction and the rear wheels are in the toe-out direction.

[0023] First, as shown in FIG. 1(b), the control unit 15 operates the wheels 11 so that the front wheels among the wheels 11 are in the toe-in state and the rear wheels are in the toe-out state according to the operation by the driver (step S11). This time is set as T0. As shown in FIGS. 1(b) and 3, in this case, the speed of the super-low-speed turn is 0, and the angles of the front wheels of the wheels 11 facing in the toe-in direction and the rear wheels facing in the toe-out direction are each set as θ1.

[0024] As shown in FIG. 1(c), the vehicle 1 performs a super-low-speed turn by rotating the wheels 11 (step S12). At this time, as shown in FIG. 3, until the time T1 when the speed of the vehicle 1 reaches the predetermined speed V1, the rotation speed of the wheels 11 is accelerated while keeping the angle θ of the wheels 11 in the state of θ1.

[0025] As shown in FIG. 3, when the speed of the over-reliance turning of the vehicle 1 reaches a predetermined speed V1, the control unit 15 performs control to change the angle of the wheels 11 so that the speed of the over-reliance turning decreases compared to the state where the wheels 11 are at the optimal angle (step S13). That is, as shown in FIG. 1(d), the control unit 15 performs control to change the angle of the wheels 11 to θ2, which is an angle between 0° and θ1. Note that the angle θ2 is a predetermined angle determined in advance and is the second angle.

[0026] Here, as shown in FIG. 3, it is assumed that the angle θ of the wheels 11 is gradually changed from time T1 to time T2 and becomes θ2 at time T2. Also, the speed of the over-reliance turning of the vehicle 1 is decelerated after once reaching the speed peak from time T1 to time T2 due to the braking effect that makes it difficult to turn by changing the angle of the wheels 11 and the operation of the driver's brake pedal or the like.

[0027] At this time, in the vehicle 1, by changing the angle θ of the wheels 11 from the optimal angle θ1 to θ2, the resistance of the wheels 11 during turning can be increased compared to the case of performing over-reliance turning in the state of θ1. That is, in the vehicle 1, the increase in speed during over-reliance turning is suppressed by the increase in the resistance of the wheels 11.

[0028] As shown in FIG. 3, after time T2, the vehicle 1 decreases the speed of the over-reliance turning while keeping the angle of the wheels 11 in the state of θ2 (step S14). At this time, in the vehicle 1, it is possible to accelerate or decelerate according to the operation of the driver's accelerator pedal or brake pedal, but here it is assumed that deceleration is performed by operating the brake pedal. Thereby, the vehicle 1 performs over-reliance turning while decelerating until it reaches the direction intended by the driver, and then stops.

[0029] In FIG. 3, the angle θ2 of the wheels is set to a constant angle, but it may be variable. Also, for example, in the control unit 15, since a value corresponding to the operation of the brake pedal is acquired, it is also possible to change the value of the angle θ2 of the wheels after the speed of the super high-g turn reaches a predetermined speed according to the acquired value, that is, the state of the operation by the driver.

[0030] As a result, in the vehicle 1, when the speed of the super high-g turn reaches a predetermined speed, by changing the direction of the wheels 11, the resistance of the wheels 11 can be increased to generate a braking force and suppress acceleration. That is, in the vehicle 1, by changing the angle of the wheels 11 executed by the control unit 15, the sudden acceleration during the super high-g turn can be suppressed, making it easier for the driver to adjust the speed.

[0031] Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist. That is, the above description has been appropriately omitted and simplified for clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiment within the scope of the present invention.

[0032] For example, in the above, all four wheels 11 were described as drive wheels that receive the driving force generated by the driving force generation unit 12 and operate, but for example, a two-wheel drive vehicle in which the front wheels are drive wheels and the rear wheels are driven wheels may also be used.

[0033] Also, in the above, for all four wheels 11, the angle θ1 optimal for the super high-g turn was set until time T1, and it was described that the angle is changed to θ2 at time T2, but it is not limited to this. As an example, the control unit 15 controls to change the angle of the wheels to θ2 at time T2 in a combination of the front left side and the rear right side, or the front right side and the rear left side, which are arranged at diagonal positions among the four wheels 11, thereby reducing the speed of the super high-g turn.

[0034] Similarly, for at least one of the four wheels 11, by changing the angle of the wheel from the state of θ1 that is optimal for extremely sharp turning to θ2, it is possible to reduce the speed of extremely sharp turning.

[0035] Also, regarding θ2 which is the angle of the wheel at time T2, although it was described as being an angle between 0° and the optimal angle θ1, the angle of θ2 may be an angle larger than θ1, that is, an angle between θ1 and 90°. As an example, θ1 can be 45° and θ2 can be 60°.

[0036] In addition, in the above description, the case where the vehicle 1 is equipped with four wheels 11 was explained, but the number of wheels 11 is not limited to four and can be arbitrarily changed.

[0037] In the above, it was assumed that the angle θ1 of the wheel when the vehicle 1 starts extremely sharp turning is the optimal angle when performing extremely sharp turning, but it does not necessarily have to be the optimal angle. In other words, in the vehicle 1, until it starts extremely sharp turning and reaches a predetermined speed, the wheels 11 are set at a predetermined angle θ1 at which extremely sharp turning is possible, and after reaching the predetermined speed, as long as the wheels 11 can be changed to an angle θ2 that is not suitable for extremely sharp turning compared to before reaching the predetermined speed. For example, θ1 can be 40° and θ2 can be 25°.

Explanation of symbols

[0038] 1 Vehicle 11 Wheels 12 Driving force generation unit 13 Steering unit 14 Brake system 15 Control unit

Claims

【Claim 1】 A step of performing a super-sticky turn with the wheel angle in a first angle state; When the speed of the super-sticky turn increases and reaches a predetermined speed, changing the wheel angle to a second angle at which the resistance of the wheel during the super-sticky turn increases compared to the state of the first angle. And, A method for controlling a vehicle.

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