Control method and system for controlling the in-situ rotation mode of four-wheel independent steering type vehicles

Abstract

The present invention relates to a method and system for controlling a rotation mode in place that reduces driving anxiety and the risk of accidents by easily and conveniently operating the rotational behavior of a vehicle in place. The present invention introduces a method and system for controlling a rotation mode in place of a four-wheel independent steering vehicle, comprising a controller that, when the vehicle enters a rotation mode in place, steers the wheel to match the rotation mode in place; when the steering wheel is steered, calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel; and when an accelerator pedal input signal is applied, controls the vehicle to rotate in place by the target rotation angle.

Description

Technology Field

[0001] The present invention relates to a method and system for controlling a rotation mode of a four-wheel independent steering vehicle, which reduces driving anxiety and the risk of accidents by easily and conveniently operating the vehicle's rotational behavior in place. Background Technology

[0003] Conventional vehicles can be driven intuitively using only a few controls because they steer the wheels in only two modes (straight and left / right turns). In contrast, the 4-wheel independent steering system (4WS) can control each wheel independently, allowing for a variety of vehicle behaviors.

[0004] Referring to FIGS. 1a and 1b, in a normal front-wheel and rear-wheel driving mode, the wheel rotates as much as the steering wheel is turned, and the vehicle accelerates as much as the accelerator pedal is pressed, allowing the vehicle to rotate while driving forward. At this time, the reverse steering of the rear wheel relative to the front wheel can be determined based on the vehicle speed or steering angle, etc., which can help reduce the turning radius during a U-turn.

[0005] In addition, in the diagonal movement mode as shown in Fig. 1c, the rear wheels are controlled in phase with respect to the front wheels, so that yaw does not occur in the vehicle. This has advantages when changing lanes or overtaking a vehicle ahead.

[0006] In addition, in the parallel movement mode as shown in Fig. 1d, the front and rear wheels can rotate 90°, which is advantageous for parallel parking.

[0007] In addition, in a stationary rotation mode as shown in Fig. 1e, the front and rear wheels can rotate 45°, allowing the vehicle to make a U-turn in alleyways, etc.

[0009] Meanwhile, the stationary rotation mode is one of the most unique driving modes of 4WS, along with the parallel translation mode. As a unique mode, it differentiates itself from existing vehicles and can appeal to customers, but it has the following problems.

[0010] First, the stationary rotation mode is a mode in which only yaw motion occurs; however, since this type of yaw motion is unfamiliar to the driver, it can result in an unpleasant sensation of the vehicle's movement.

[0011] Secondly, in the stationary rotation mode, the direction of the vehicle's movement and the direction of the driver's line of sight do not coincide. Therefore, the driver must turn their entire body to secure a line of sight and drive in a state of anxiety regarding when to stop the rotation, which poses a problem of difficulty in driving maneuvers and a risk of accidents.

[0013] The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. Prior art literature

[0015] KR 10-0178945 B1 The problem to be solved

[0016] The present invention has been devised to solve the problems described above, and aims to provide a method and system for controlling a rotation mode of a four-wheel independent steering vehicle that reduces driving anxiety and the risk of accidents by easily and conveniently operating the vehicle's rotational behavior in place. means of solving the problem

[0018] The configuration of the present invention for achieving the above-mentioned purpose may be characterized by comprising: a wheel rotation step in which a controller steers and rotates a wheel in accordance with the rotation mode when the vehicle enters the rotation mode; a target rotation angle calculation step in which the controller calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel when the steering wheel is steered; and a rotation control step in which the controller controls the vehicle to rotate in place by the target rotation angle when an accelerator pedal input signal is applied.

[0019] In the above target rotation angle calculation step, the process is divided into steps according to the steering angle range of the steering wheel; and a target rotation angle can be set for each step.

[0020] The above steering angle range can be set by having a certain angle range continuously connected.

[0021] The above target rotation angle calculation step can be performed by operating a separately provided mechanism.

[0022] In the above target rotation angle calculation step, a separate step rotation mode button is provided on the side of the shift lever, and the target rotation angle can be calculated when the step rotation mode button is operated.

[0023] The above target rotation angle calculation step can calculate the target rotation angle when a specific button among the shift buttons is pressed a certain number of times or more, or pressed for a certain period of time or more.

[0024] In the above target rotation angle calculation step, the target rotation angle can be set by continuously changing in correspondence with the steering angle of the steering wheel.

[0025] In the above rotation control step, when the vehicle rotates in place, the steering wheel can be rotated in the opposite direction to the vehicle's rotation direction by an amount equal to the angle of rotation of the vehicle.

[0026] In the above rotation control step, the steering wheel is rotated in the opposite direction to the vehicle's rotation direction simultaneously with the vehicle's rotation and in accordance with the angle of rotation of the vehicle; and when the vehicle's rotation ends, the steering wheel is restored to the opposite direction by the angle of rotation of the vehicle to indicate the end point of rotation in place.

[0027] In the above rotation control step, when the vehicle rotates in place, the steering wheel can be rotated in the opposite direction to the vehicle's rotation direction by an amount equal to the steering angle at which the driver steers the steering wheel.

[0028] In the above rotation control step, the steering wheel is rotated in the opposite direction to the vehicle's rotation direction in accordance with the steering angle steered by the driver for the vehicle's rotation in place simultaneously with the vehicle's rotation; and when the vehicle's rotation ends, the steering wheel is restored to the opposite direction to the vehicle's rotation direction by the steering angle steered by the driver, thereby allowing the end point of the rotation in place to be recognized.

[0029] In the above rotation control step, when the steering wheel is additionally steered in the direction of vehicle rotation while the vehicle is rotating in place, the vehicle can be rotated further by an additional steering angle of the steering wheel.

[0030] In the above rotation control step, the rotation angle of the vehicle can be guided through a notification means.

[0031] The above notification means can display the vehicle's rotation angle on the cluster or provide voice guidance.

[0032] The above notification means can provide a warning sound at every certain angle of rotation while the vehicle is rotating in place.

[0033] The above notification means can provide a temporarily different steering sensation to the steering wheel at every certain angle of rotation while the vehicle is rotating in place.

[0034] In the above rotation control step, the rotational speed of the vehicle is determined according to the amount of acceleration pedal pressure, and the vehicle can be rotated.

[0035] In the above rotation control step, the rotational acceleration can be gradually increased within the range of accelerator pedal pressure during the initial rotation of the vehicle.

[0036] In the above rotation control step, the rotational acceleration can be gradually reduced before reaching the target rotation angle at the end of the vehicle's rotation.

[0037] In the above rotation control step, when the brake pedal is pressed while the vehicle is rotating, the rotation speed of the vehicle can be reduced.

[0038] The present invention may be characterized by including a controller that, when the vehicle enters a stationary rotation mode, steers the wheel in accordance with the stationary rotation mode, calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel when the steering wheel is steered, and controls the vehicle to rotate in place by the target rotation angle when an accelerator pedal input signal is applied. Effects of the invention

[0040] Through the above-described means for solving the problem, the present invention sets a target rotation angle equal to the amount of steering the driver operates the steering wheel, and causes the vehicle to rotate in place by the set target rotation angle. This not only accurately controls the rotation angle of the vehicle but also allows the driver to easily and comfortably operate the vehicle's rotation in place function, thereby reducing driving anxiety and preventing steering wheel operation errors caused by dizziness during rotation, thus having the effect of reducing the risk of accidents. Brief explanation of the drawing

[0042] FIGS. 1a to 1f are drawings for explaining the steering rotation of the wheels and the behavior of the vehicle for each driving mode of a four-wheel independent steering vehicle. FIG. 2 is a block diagram illustrating a control system of a four-wheel independent steering vehicle according to the present invention. FIG. 3 is a drawing for explaining the operation of a vehicle according to the present invention, wherein the rotation in place is set in 30° increments. FIG. 4 is a drawing for explaining the operation of a vehicle according to the present invention in which rotation in place is set in 45° increments. FIGS. 5 and 6 are drawings briefly illustrating a mode switching mechanism applied to a four-wheel independent steering vehicle according to the present invention. FIG. 7 is a diagram showing the rotational behavior of the steering wheel and the vehicle in stages during the rotation process of the vehicle in place according to the present invention. FIG. 8 is a diagram illustrating the operation of warning of the rotation angle in place through a change in the feel of operation in the present invention. FIG. 9 is a flowchart illustrating, in general, the control process of the rotational rotation mode of a four-wheel independent steering vehicle according to the present invention. Specific details for implementing the invention

[0043] A preferred embodiment of the present invention will be described in detail below with reference to the attached drawings.

[0045] FIG. 2 is a diagram illustrating a driving mode switching control system of a four-wheel independent steering vehicle according to the present invention.

[0046] Referring to the drawings, the four-wheel steering system applicable to the present invention is configured to include a driving mode switching mechanism (10), a steering wheel (20), an accelerator pedal (30) and a brake pedal (40), an ECU (controller), corner modules (60a, 60b, 60c, 60d) that perform independent steering operation for each wheel, and a controller (50).

[0048] Specifically, the driving mode switching mechanism (10) can be implemented through a shift lever that is moved and operated within the shift gate as shown in FIG. 5, and can also be implemented through a shift button as shown in FIG. 6.

[0049] For example, in the case of the shift lever type of FIG. 5, a shift gate is formed along the movement path of the shift lever, and a general driving mode including a P mode (11), a D mode (12), and an R mode (13), and a special driving mode including a diagonal driving mode (14), a parallel movement mode (15), and a stationary rotation mode (16) are arranged along the movement path of the shift lever.

[0050] In addition, in the case of the shift button type of Fig. 6, it can be arranged in the form of buttons for each of the general driving mode and special driving mode.

[0051] In addition, referring to FIG. 2, a steering angle sensor (21) is connected to the steering wheel (20), thereby detecting the steering angle through the steering angle sensor (21) and transmitting it to the controller (50). For reference, a steering reaction force mechanism that generates the steering reaction force of the steering wheel (20) may be optionally added.

[0052] The accelerator pedal (30) is capable of operating the throttle valve, and the input signal of the accelerator pedal (30) is detected through the APS (31), and the detected signal is transmitted to the controller (50).

[0053] The brake pedal (40) is connected to a braking mechanism and can operate the braking mechanism. The brake pedal (40) also detects a step signal through the BPS (41), and the detected signal is transmitted to the controller (50).

[0054] The corner modules (60a, 60b, 60c, 60d) may utilize existing corner modules, but to maximize the utility of 4-wheel independent steering operations such as parallel parking and turning in place, the counter-steering angle corner modules (60a, 60b, 60c, 60d) that can be steered up to 90˚ to one side are suitable.

[0055] The counter-steering angle corner modules (60a, 60b, 60c, 60d) may be configured to include a suspension system capable of sufficiently moving through the gap with the wheel, a high-angle drive shaft or in-wheel system, and a steering actuator that provides operating force to independently steer the counter-steering angle corner modules (60a, 60b, 60c, 60d).

[0057] In particular, the controller (50) according to the present invention rotates the wheel in accordance with the rotation mode (16) of the vehicle when the vehicle enters the rotation mode, calculates the target rotation angle of the vehicle based on the steering angle of the steering wheel (20) when the steering wheel (20) is steered, and controls the vehicle to rotate in place by the target rotation angle when the accelerator pedal (30) is pressed signal is applied.

[0058] For reference, the controller (50) according to an exemplary embodiment of the present invention may be an ECU.

[0059] And, the controller (50) may be implemented through a non-volatile memory (not shown) configured to store data regarding an algorithm configured to control the operation of various components of the vehicle or software instructions for reproducing said algorithm, and a processor (not shown) configured to perform the operation described below using the data stored in said memory. Here, the memory and the processor may be implemented as separate chips. Alternatively, the memory and the processor may be implemented as a single chip integrated with each other. The processor may take the form of one or more processors.

[0061] Meanwhile, in the present invention, the method for controlling the rotation mode of a four-wheel independent steering vehicle using the controller (50) can be configured to include a wheel rotation step, a target rotation angle calculation step, and a rotation control step.

[0063] First, in the wheel rotation stage, the controller (50) steers and rotates the wheel in accordance with the rotation mode when the vehicle enters the rotation mode.

[0064] For example, when the driver selects the stationary rotation mode through the driving mode switching mechanism (10), the vehicle enters the stationary rotation mode, and when entering the stationary rotation mode, the front and rear wheels are steered and rotated using the corner modules (60a, 60b, 60c, 60d) to be suitable for stationary rotation.

[0065] At this time, it is preferable to steer the left front wheel and the right rear wheel 45° to the right and the right front wheel and the left rear wheel 45° to the left as in FIG. 1e, but they can also be steered in the form as in FIG. 1f, and the rotation angles of the front and rear wheels can be steered in various forms that allow for rotation in place.

[0067] In the target rotation angle calculation step, the controller (50) calculates the target rotation angle of the vehicle based on the steering angle of the steering wheel (20) when steering the steering wheel (20).

[0068] That is, when the driver steers the steering wheel (20) in the desired direction of rotation while in the stationary rotation mode, the target angle at which the vehicle rotates in place is calculated based on the steering angle detected by the steering angle sensor (21).

[0070] In the rotation control stage, the controller (50) can control the vehicle to rotate in place by the target rotation angle when the accelerator pedal (30) is pressed.

[0071] That is, after setting the target rotation angle, when the driver presses the accelerator pedal (30), driving force is applied to the drive wheel to perform rotation of the vehicle in place.

[0073] In this way, the present invention sets a target rotation angle equal to the amount of steering the driver operates the steering wheel (20), and the vehicle rotates in place by the set target rotation angle, thereby allowing the driver to easily and comfortably operate the vehicle's rotation function in place, thereby reducing driving anxiety and lowering the risk of accidents.

[0075] Meanwhile, in the step of calculating the target rotation angle of the present invention, the steps are divided according to the steering angle range of the steering wheel (20); and the target rotation angle can be set for each step.

[0076] That is, as a preferred embodiment for calculating the target rotation angle, the rotation angle of the vehicle can be set by recognizing it step by step according to the amount of steering the driver rotates the steering wheel (20).

[0077] For example, FIG. 3 is a drawing for explaining the operation of rotating a vehicle in place according to the present invention, in which the rotation is divided into 30° increments, and shows an example in which a 90° rotation angle is divided into three steps in 30° increments.

[0078] Accordingly, when the driver turns the steering wheel (20) between 30˚ and 60˚, the target rotation angle is set to 30˚, allowing the vehicle to rotate in place by only 30˚.

[0079] As another example, FIG. 4 is a drawing for explaining the operation of rotating a vehicle in place according to the present invention, in which the rotation is divided into 45° increments, and shows an example in which a rotation angle of 180° is divided into 4 steps in 45° increments.

[0080] Accordingly, when the driver turns the steering wheel (20) between 45˚ and 90˚, the target rotation angle is set to 45˚, allowing the vehicle to rotate in place by only 45˚.

[0081] As such, in the present invention, the steering angle range can be set by having a certain angle range continuously connected.

[0082] That is, as shown in Fig. 3, the steering angle range for each step can be set in 30° increments, and as shown in Fig. 4, the steering angle range for each step can be set in 45° increments.

[0083] Of course, the rotation angle and step exemplified in FIGS. 3 and 4 are merely examples for setting the target rotation angle step by step, and the rotation angle and step can be changed in various forms.

[0084] Therefore, the driver can accurately control the turning angle of the vehicle by rotating it by a preset angle without having to worry about the timing to stop the vehicle, and thereby prevents errors in operating the steering wheel (20) due to dizziness during rotation, thereby reducing the risk of accidents.

[0086] However, the target rotation angle setting method described above may not accurately reflect the rotation angle in place desired by the driver in the vehicle's rotation angle.

[0087] Accordingly, in the present invention, the step of calculating the target rotation angle step by step can be configured to be operated by a separate operation.

[0088] For example, in the case of a gear lever type, a separate step rotation mode button (17) is provided on the upper side of the gear lever so that when the driver operates the step rotation mode button (17), the target rotation angle can be calculated step by step.

[0089] As another example, in the case of a shift button type, the target rotation angle can be calculated step by step when the stationary rotation mode button is pressed two or more times consecutively or for a certain period of time.

[0090] For example, in the case of a concept of rotating the vehicle in 4 steps of 30°, even if the driver rotates the steering wheel (20) to rotate the vehicle by 100°, the target rotation angle becomes 90°, so the vehicle is rotated only 90°.

[0091] Therefore, by configuring the system to calculate the target rotation angle step by step only when the step rotation mode button is operated, the convenience of the vehicle's stationary rotation function can be enhanced, even if it does not accurately reflect the driver's intention.

[0093] In addition, as another example of the above-mentioned target rotation angle calculation step, the target rotation angle can be set to change continuously in correspondence with the steering angle of the steering wheel (20).

[0094] That is, when the steering wheel (20) is rotated 100°, the target rotation angle is also set to 100°, and the vehicle is rotated in place by 100°.

[0095] Therefore, the vehicle can rotate in place by accurately reflecting the driver's intention.

[0097] Meanwhile, FIG. 7 is a diagram showing the rotational behavior of the steering wheel (20) and the vehicle in stages during the rotation process of the vehicle in place according to the present invention.

[0098] Referring to the drawing, in the rotation control step, when the vehicle rotates in place, the steering wheel (20) can be rotated in the opposite direction to the vehicle's rotation direction by an angle of rotation of the vehicle.

[0099] Specifically, as the vehicle rotates, the steering wheel rotates in the opposite direction to the vehicle's rotation direction in accordance with the angle of rotation; and when the vehicle's rotation ends, the steering wheel returns to the opposite direction by the angle of rotation, thereby allowing the end point of the rotation in place to be recognized.

[0101] That is, when the vehicle enters the stationary rotation mode, if the driver rotates the steering wheel (20) clockwise, the vehicle rotates clockwise in place by the target rotation angle.

[0102] Accordingly, as the vehicle rotates in place, the steering wheel (20) is restored to a counterclockwise direction opposite to the vehicle's rotation direction by the angle of rotation, so that when the vehicle has completed rotation by the target rotation angle, the absolute angle of the steering wheel remains the same as the state before the vehicle's rotation.

[0103] Accordingly, by restoring the steering wheel (20) by the angle of rotation of the vehicle, the steering direction of the vehicle before rotation can be maintained, and the driver is notified of the point at which the vehicle's rotation in place is completed. This allows the driver to easily recognize the point at which the rotation in place operation is completed, thereby increasing the convenience of the rotation in place function and reducing the risk of accidents.

[0105] However, in the step of calculating the target rotation angle according to the present invention, when the target rotation angle is calculated step by step, the vehicle's rotation angle in place may be rotated less than the steering angle at which the driver steers the steering wheel, and thus the restoring rotation of the steering wheel may not be restored to the steering wheel position immediately before the vehicle's rotation in place.

[0106] Accordingly, the present invention can control the steering wheel to return to its original rotation in response to the steering angle of the steering wheel steered by the driver for rotation in place.

[0107] This can also be explained with reference to Fig. 7. In the rotation control step, when the vehicle rotates in place, the steering wheel can be rotated in the opposite direction to the vehicle's rotation direction by the steering angle at which the driver steers the steering wheel.

[0108] Specifically, simultaneously with the vehicle's rotation, the steering wheel rotates in the opposite direction to the vehicle's rotation direction in accordance with the steering angle steered by the driver for the vehicle's rotation in place; and when the vehicle's rotation ends, the steering wheel returns to a rotation in the opposite direction to the vehicle's rotation direction by the steering angle steered by the driver, thereby allowing the driver to recognize the end point of the rotation in place.

[0110] That is, when the vehicle enters the stationary rotation mode, if the driver rotates the steering wheel (20) clockwise, the vehicle rotates clockwise in place by the target rotation angle.

[0111] Accordingly, as the vehicle rotates in place, the steering wheel (20) is restored to a counterclockwise direction opposite to the vehicle's rotation direction by the steering angle set by the driver, so that when the vehicle has completed rotation by the target rotation angle, the absolute angle of the steering wheel remains in the same state as before the vehicle's rotation.

[0112] Accordingly, as the steering wheel (20) is restored to the same angle as the driver rotated the steering wheel (20), the steering direction of the vehicle before rotation can be maintained, and the driver is notified of the point at which the vehicle's rotation in place is completed. This allows the driver to easily recognize the point at which the rotation in place operation is completed, thereby increasing the convenience of the rotation in place function and reducing the risk of accidents.

[0114] In addition, in the above rotation control step, when the steering wheel (20) is additionally steered in the direction of rotation of the vehicle while the vehicle is rotating in place, the vehicle can be further rotated by an additional steering angle of the steering wheel (20).

[0115] That is, when the driver rotates the steering wheel (20) clockwise and the vehicle rotates clockwise in the process, if the driver further rotates the steering wheel (20) clockwise, which is the rotation direction of the vehicle, the vehicle rotates clockwise further by the rotation angle of the steering wheel (20), thereby allowing the driver to rotate the vehicle by the desired rotation angle.

[0117] Meanwhile, in the rotation control step of the present invention, the rotation angle of the vehicle can be guided through a notification means.

[0118] For example, as a preferred embodiment of the above notification means, the rotation angle of the vehicle can be displayed on the cluster or provided as voice guidance.

[0119] When displayed on the cluster, it can provide guidance on the smooth operation of the accelerator pedal (30) along with the angle at which the vehicle rotates in place.

[0121] In addition, as another embodiment of the above notification means, a warning sound can be provided at every certain angle of rotation while the vehicle is rotating in place.

[0122] For example, as shown in Fig. 4, if the vehicle rotates by 30° at each step, a warning sound can be provided every 30°.

[0124] In addition, as another embodiment of the above notification means, it can be configured to provide a temporarily different operating sensation to the steering wheel (20) at every certain rotation angle while the vehicle is rotating in place.

[0125] For example, FIG. 8 is a diagram illustrating an operation to warn of the rotation angle in place through a change in the feel of the operation in the present invention. When the vehicle rotates by 30° at each step, it can be configured to provide a catching sensation to the steering wheel (20) every 30°.

[0127] Meanwhile, in the rotation control step, the present invention allows the vehicle's rotational speed to be determined according to the amount of pressure applied to the accelerator pedal (30), thereby enabling the vehicle to rotate in place.

[0128] For example, in the case of a vehicle where the driving means (70) is an engine, the throttle opening amount is adjusted to the extent that the driver presses the accelerator pedal (30) to rotate the vehicle, and in the case of a vehicle where the driving means (70) is a motor, the output of the motor is determined to the extent that the driver presses the accelerator pedal (30) to rotate the vehicle.

[0130] However, in the above rotation control step, the rotational acceleration can be gradually increased within the range of the amount of pressure applied to the accelerator pedal (30) at the beginning of the vehicle's rotation.

[0131] That is, if the driver presses the accelerator pedal (30) excessively during the initial rotation in place, problems such as dizziness due to the sudden turn of the vehicle, instability of the vehicle's movement, and shortening of the lifespan of related chassis parts may occur.

[0132] Accordingly, by slowly increasing the yaw speed within the range of the amount of acceleration pedal (30) pressed by the driver at the beginning of the vehicle's rotation, smooth rotational acceleration is achieved, thereby preventing sudden acceleration at the start of the vehicle's rotation, providing a smooth ride, and enabling the vehicle to be rotated safely. Of course, such control of rotational acceleration can also be achieved by adjusting the throttle opening amount or adjusting the motor output.

[0134] In addition, in the above rotation control step, the rotational acceleration can be gradually reduced before reaching the target rotation angle at the end of the vehicle's rotation.

[0135] In other words, by gradually reducing the yaw speed to enable smooth deceleration not only at the beginning of the turn but also at the end, sudden deceleration is prevented, thereby providing a smooth ride.

[0136] In particular, when controlling rotational acceleration at the end of a vehicle turn, acceleration control can be made simpler because braking is not performed by the driver's will, but rather the vehicle is controlled to stop automatically at the target rotation angle.

[0138] However, in the present invention, when the driver presses the brake pedal (40) while the vehicle is turning, the vehicle must be able to stop.

[0139] To this end, in the above rotation control step, when the brake pedal (40) is pressed while the vehicle is rotating, the rotation speed of the vehicle is reduced.

[0140] That is, when the driver presses the brake pedal (40) while the vehicle is turning, the vehicle is decelerated when the brake pedal (40) signal is applied, because the driver perceives internal / external danger to the vehicle and intends to stop the vehicle.

[0142] FIG. 9 is a flowchart illustrating the entire process of controlling the rotational mode of a four-wheel independent steering vehicle according to the present invention.

[0143] Referring to the drawing, when the driver selects the stationary rotation mode by operating the gear lever or gear button, it is determined whether the absolute value of the steering angle exceeds β° (within 2 degrees) (S10).

[0144] Accordingly, when the absolute value of the steering angle exceeds β°, the front and rear wheels are steered by 45° using corner modules (60a, 60b, 60c, 60d) (S20).

[0145] Next, it is determined whether the step rotation mode is selected (S30).

[0146] If the step rotation mode button is selected as a result of the judgment in step S30, the steering angle is detected and the target rotation angle is set according to the steering angle range.

[0147] For example, if three steps of rotation are set in 30° increments, determine whether the absolute value of the steering angle exceeds 90° (S31), and if it exceeds 90°, set the target rotation angle (α) to 90° (S32).

[0148] On the other hand, if the absolute value of the steering angle does not exceed 90°, determine whether the absolute value of the steering angle exceeds 60° (S33), and if it exceeds 60°, set the target rotation angle (α) to 60° (S34).

[0149] Then, if the absolute value of the steering angle does not exceed 60°, determine whether the absolute value of the steering angle exceeds 30° (S35), and if it exceeds 30°, set the target rotation angle (α) to 30° (S36).

[0150] However, if the step rotation mode button is not selected as a result of the judgment in step S30, the steering angle is detected and the target rotation angle is set corresponding to the steering angle.

[0151] That is, when the absolute value of the steering angle is 100°, the target rotation angle (α) is set to 100° (S37).

[0152] Next, it is determined whether the accelerator pedal (30) signal is turned on (S40), and when the accelerator pedal (30) signal is turned on, it is determined whether the steering angle is greater than 0° (S50), and the direction of rotation of the steering wheel (20) is determined.

[0153] For example, if the steering angle is greater than 0°, it is determined that the steering wheel (20) is in a right-hand turn situation, and the driving means (70) for turning the vehicle is rotated in the forward direction to rotate the vehicle clockwise in place (S51).

[0154] On the other hand, if the steering angle is not greater than 0°, it is determined that the steering wheel (20) is in a left-turning state, and the driving means (70) for rotating the vehicle is rotated in the reverse direction to rotate the vehicle in place in a counterclockwise direction (S52).

[0155] Next, it is determined whether the brake pedal (40) signal is turned on (S60), and if the brake pedal (40) signal is not turned on, it is determined whether the absolute value of the vehicle rotation angle matches the previously set target rotation angle to determine whether the rotation in place has been achieved as intended by the driver (S70).

[0156] Then, determine whether the stationary rotation speed has become 0 (S80), and if it has become 0, terminate the control.

[0157] And, as a result of the judgment in step S60, even if the brake pedal (40) signal is applied, move to step S80 to determine whether the stationary rotation speed has become 0, and if it has become 0, terminate the control.

[0159] As described above, the present invention sets a target rotation angle equal to the amount of steering the driver operates the steering wheel (20), and the vehicle rotates in place by the set target rotation angle. This not only accurately controls the rotation angle of the vehicle, but also allows the driver to easily and comfortably operate the vehicle's rotation function in place, thereby reducing driving anxiety and preventing errors in operating the steering wheel (20) due to dizziness during rotation, thereby reducing the risk of accidents.

[0161] Meanwhile, although the present invention has been described in detail only with respect to the specific examples mentioned above, it is obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical spirit of the invention, and it is natural that such modifications and variations fall within the scope of the appended claims. Explanation of the symbols

[0163] 10: Driving mode switching mechanism 20: Steering wheel 21: Steering angle sensor 30 : Accelerator pedal 31 : APS 40 : Brake pedal 41 : BPS 50 : Controller 60a, 60b, 60c, 60d: Corner modules 70 : Driving means

Claims

Claim 1 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle, comprising: a wheel rotation step in which a controller rotates a wheel in accordance with the stationary rotation mode when the vehicle enters the stationary rotation mode; a target rotation angle calculation step in which a controller calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel when the steering wheel is steered; and a rotation control step in which a controller controls the vehicle to rotate in place by the target rotation angle when an accelerator pedal input signal is applied; wherein the target rotation angle calculation step is characterized by having a separate step rotation mode button provided on the side of the gear shift lever, and calculating the target rotation angle when the step rotation mode button is operated. Claim 2 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, wherein the target rotation angle calculation step is divided into steps according to the steering angle range of the steering wheel; and a target rotation angle is set for each step. Claim 3 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 2, characterized in that the steering angle range is set by a continuous series of angle ranges. Claim 4 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 2, wherein the step of calculating the target rotation angle is performed according to the operation of a separately provided mechanism. Claim 5 delete Claim 6 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle, comprising: a wheel rotation step in which a controller rotates a wheel in accordance with the stationary rotation mode when the vehicle enters the stationary rotation mode; a target rotation angle calculation step in which a controller calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel when the steering wheel is steered; and a rotation control step in which a controller controls the vehicle to rotate in place by the target rotation angle when an accelerator pedal input signal is applied; wherein the target rotation angle calculation step is characterized by calculating the target rotation angle when a specific button among the gear shift buttons is pressed a certain number of times or more, or pressed for a certain period of time or more. Claim 7 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, characterized in that, in the step of calculating the target rotation angle, the target rotation angle is continuously changed and set in correspondence with the steering angle of the steering wheel. Claim 8 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, wherein in the rotation control step, when the vehicle rotates in place, the steering wheel is rotated in a direction opposite to the direction of rotation of the vehicle by an angle of rotation of the vehicle. Claim 9 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 8, wherein, in the rotation control step, the steering wheel is rotated in the opposite direction to the vehicle's rotation direction in accordance with the angle of rotation of the vehicle simultaneously with the vehicle's rotation; and when the vehicle's rotation ends, the steering wheel is restored to the opposite direction by the angle of rotation of the vehicle to recognize the end point of the stationary rotation. Claim 10 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, wherein in the rotation control step, when the vehicle rotates in place, the steering wheel is rotated in a direction opposite to the vehicle's rotation direction by an amount of the steering angle at which the driver steers the steering wheel. Claim 11 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 10, wherein, in the rotation control step, the steering wheel is rotated in the opposite direction to the vehicle's rotation direction in accordance with the steering angle steered by the driver for stationary rotation of the vehicle simultaneously with the vehicle's rotation; and when the vehicle's rotation ends, the steering wheel is restored to the opposite direction to the vehicle's rotation direction by the steering angle steered by the driver to recognize the end point of stationary rotation. Claim 12 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, wherein in the rotation control step, when the steering wheel is additionally steered in the direction of rotation of the vehicle while the vehicle is rotating in place, the vehicle is further rotated by an additional steering angle of the steering wheel. Claim 13 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, wherein the rotation control step is characterized by guiding the rotation angle of the vehicle through a notification means. Claim 14 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 13, wherein the notification means displays the rotation angle of the vehicle on a cluster or provides voice guidance. Claim 15 A method for controlling a rotation mode of a four-wheel independent steering vehicle according to claim 13, wherein the notification means provides a warning sound at every certain rotation angle during rotation of the vehicle. Claim 16 A method for controlling a rotation mode of a four-wheel independent steering vehicle according to claim 13, wherein the notification means provides a temporarily different operating sensation to the steering wheel at each rotation angle during rotation of the vehicle. Claim 17 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, characterized in that, in the rotation control step, the rotational speed of the vehicle is determined according to the amount of acceleration pedal application and the vehicle is rotated. Claim 18 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, characterized in that, in the rotation control step, the rotational acceleration is gradually increased within the range of the amount of acceleration pedal pressure applied at the beginning of the vehicle's rotation. Claim 19 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, characterized in that, in the rotation control step, the rotational acceleration is gradually reduced before reaching a target rotation angle at the end of the vehicle's rotation. Claim 20 A method for controlling a stationary rotation mode of a four-wheel independent steering vehicle according to claim 1, characterized in that, in the rotation control step, the rotation speed of the vehicle is reduced when the brake pedal is pressed during the rotation of the vehicle. Claim 21 A control system for a stationary rotation mode of a four-wheel independent steering vehicle, comprising: a controller that, when the vehicle enters a stationary rotation mode, steers the wheel in accordance with the stationary rotation mode, calculates a target rotation angle of the vehicle based on the steering angle of the steering wheel when the steering wheel is steered, and controls the vehicle to rotate in place by the target rotation angle when an accelerator pedal input signal is applied; and a separate step rotation mode button provided on the side of the gear lever, wherein the target rotation angle is calculated when the step rotation mode button is operated.

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