Apparatus for assisting steering of a vehicle and method of controlling the same

Abstract

The present invention relates to a device for assisting a vehicle in steering and a control method thereof, which can include a turning direction recognizer that recognizes a turning direction of a tire using a steering angle controlled by a handle, and a tire drive controller that determines a tire to which a first driving force is applied and a tire to which a second driving force is applied, and controls driving motors provided in each of the tires to generate the first driving force for generating a steering assist torque that assists the tire in turning in the recognized turning direction and the second driving force for canceling the first driving force to maintain a forward / backward force of the vehicle as 0, so that the tire can turn with a limit steering torque or more that can be generated by the driving motor.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0032227, filed on March 11, 2021, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates to a device for assisting vehicle steering and a control method thereof, the device being able to additionally provide the torque required to stop the vehicle steering from a drive motor. Background Technology

[0004] Typically, when a vehicle is steered using motor-driven power steering (MDPS), the steering torque applied to each tire for the desired steering angle varies depending on whether the vehicle is being driven or stopped.

[0005] In other words, the steering torque required when the vehicle is stationary is greater than the steering torque required when the coefficient of friction between the tires and the road surface is lower, and the required steering torque increases with the steering angle. Therefore, the maximum steering torque is required in the case of a full turn from a stationary position (where the steering angle is operated to the maximum extent).

[0006] Furthermore, in four-wheel independent steering wheels (where all four tires can be driven independently), there are space limitations in terms of increasing the capacity and size of steering torque because a drive motor for generating driving force on the tires and a steering motor for generating steering torque on the tires must be installed.

[0007] Therefore, there is a need for a device that can meet the steering torque required during a full turn while stationary (where the maximum steering torque is required during the turn, while minimizing the increase in the capacity of the steering motor).

[0008] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0009] Various aspects of the present invention are dedicated to providing an apparatus and control method for assisting vehicle steering, the apparatus comprising: a turning direction recognizer and a tire drive controller, the turning direction recognizer identifying the turning direction of the tires of the vehicle being steered using a steering angle controlled by a handle; the tire drive controller determining a tire to which a first driving force is applied to generate a steering assist torque to assist the tires in turning to the identified turning direction, and a tire to which a second driving force is applied to counteract the first driving force to keep the forward / reverse force of the vehicle at 0, and respectively controlling drive motors disposed on each tire to generate the first driving force and the second driving force, thereby enabling the tires to turn with a limit steering torque or greater that can be generated by the steering motors.

[0010] The technical problems solved by the present invention are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art to which the various exemplary embodiments of the present invention pertain from the following description.

[0011] According to various aspects of the present invention, an apparatus for assisting vehicle steering includes: a turning direction recognizer and a tire drive controller, the turning direction recognizer identifying the turning direction of the tires of the vehicle being steered using a steering angle controlled by a handle; the tire drive controller determining a tire to which a first driving force is applied to generate a steering assist torque to assist the tires in turning to the identified turning direction and a tire to which a second driving force is applied to counteract the first driving force to keep the forward / reverse force of the vehicle at 0, and respectively controlling drive motors disposed on each tire to generate the first driving force and the second driving force.

[0012] Furthermore, the device may further include a stop determiner that pre-determines whether the vehicle has stopped by utilizing the vehicle's wheel speed.

[0013] Furthermore, the tire drive controller can: as the tire to which a first driving force is applied, and based on the turning direction of the tire steering, determine the outer front wheel of the vehicle as the tire to which a positive (+) driving force is applied, and determine the inner front wheel of the vehicle as the tire to which a negative (-) driving force is applied.

[0014] Furthermore, the tire drive controller can: as the tire applying a second driving force, based on the turning direction of the tire steering, determine the inner rear wheel of the vehicle as the tire applying a positive (+) driving force, and determine the outer rear wheel of the vehicle as the tire applying a negative (-) driving force.

[0015] Furthermore, the tire drive controller can perform control to apply a positive (+) driving force as a first driving force to the right front wheel of the vehicle and a negative (-) driving force as a first driving force to the left front wheel of the vehicle when turning the vehicle from a stationary state to a left turn, and apply a positive (+) driving force as a second driving force to the left rear wheel of the vehicle and a negative (-) driving force as a second driving force to the right rear wheel of the vehicle.

[0016] Furthermore, the tire drive controller can perform control to apply a positive (+) driving force as a first driving force to the left front wheel and a negative (-) driving force as a first driving force to the right front wheel when turning a stationary vehicle to a right turn, and apply a positive (+) driving force as a second driving force to the right rear wheel and a negative (-) driving force as a second driving force to the left rear wheel.

[0017] Furthermore, the device may further include: a torque arm calculator, which predetermines data representing the incremental relationship between the steering angle and the torque arm using vehicle specification characteristics, stores the data in a memory, and uses the steering angle to identify the length of the torque arm that changes when the tires turn using the memory, the vehicle specification characteristics including the mounting positions of the kingpin and the steering motor, and the offset of the motor shaft.

[0018] Furthermore, the device may further include: a steering assist determiner, which determines the magnitude of the required steering torque needed to turn the tires in the left or right direction when the vehicle is stationary, based on the magnitude of the steering angle, and determines a portion of the required steering torque to be assisted by a first driving force and a second driving force generated by a drive motor when the required steering torque is greater than the limit steering torque generated by the steering motor.

[0019] In addition, the steering assist determiner can determine the ratio of the steering torque generated by the steering motor to the steering assist torque generated by the drive motor in the required steering torque.

[0020] According to various aspects of the present invention, a method for controlling assisted vehicle steering includes: a turning direction identification step and a tire drive control step, wherein the turning direction identification step identifies the turning direction of the tires steering the vehicle by utilizing a steering angle controlled by a handle; the tire drive control step determines a tire to which a first driving force is applied to generate a steering assist torque to assist the tires to the identified turning direction and a tire to which a second driving force is applied to counteract the first driving force to keep the forward / reverse force of the vehicle at 0, and controls drive motors disposed on each tire to generate the first driving force and the second driving force respectively.

[0021] Furthermore, the method may further include a vehicle stop determination step, which determines whether the vehicle has stopped by utilizing the vehicle's wheel speed before identifying a change in steering angle in the turning direction identification step.

[0022] In addition, the tire drive control steps may include steps such as, as the tire that applies the first driving force, determining the outer front wheel of the vehicle as the tire that applies the positive (+) driving force, and the inner front wheel of the vehicle as the tire that applies the negative (-) driving force, based on the turning direction of the tire steering.

[0023] In addition, the tire drive control steps may include steps such as, as the tires applying a second driving force, determining the inner rear wheel of the vehicle as the tire applying a positive (+) driving force, and the outer rear wheel of the vehicle as the tire applying a negative (-) driving force, based on the turning direction of the tire steering.

[0024] Furthermore, the method may further include the step of determining, prior to the tire drive control step, the required steering torque needed to turn the tires in the left or right direction while the vehicle is stationary, based on the steering angle, and determining, when the required steering torque is greater than the limit steering torque generated by the steering motor, a portion of the required steering torque to be assisted by a first driving force and a second driving force generated by the drive motor.

[0025] In addition, the steering assist determination step may include a step of determining the ratio of the steering torque generated by the steering motor to the steering assist torque generated by the drive motor in the required steering torque.

[0026] The methods and apparatus of the present invention have other features and advantages, which will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0027] Figure 1 This is a block diagram of a vehicle steering assist device according to various exemplary embodiments of the present invention;

[0028] Figure 2A and Figure 2B This is an exemplary schematic diagram illustrating the change in the length of the torque arm when the vehicle is turning;

[0029] Figure 3 and Figure 4 These are exemplary plan views and rear views illustrating, according to various exemplary embodiments of the invention, the additional application of driving force to the tires of a four-wheel independent steering vehicle that is steering;

[0030] Figure 5A and Figure 5B This is an exemplary schematic diagram illustrating, according to various exemplary embodiments of the present invention, the additional driving force used to generate steering assist torque being applied to the tires of a four-wheel independent steering vehicle;

[0031] Figure 6 This is a schematic diagram of a method for controlling the steering of an assisted vehicle according to various exemplary embodiments of the present invention.

[0032] It is understood that the accompanying drawings are not drawn to scale, but rather are appropriately simplified depictions illustrating various features of the basic principles of the invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific environment in which they are intended for application and use.

[0033] Throughout these figures, the same reference numerals denote the same or equivalent parts of the invention. Detailed Implementation

[0034] Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings and described below. Although the invention will be described in conjunction with exemplary embodiments thereof, it should be understood that this specification is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments thereof, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. When adding reference numerals to components in each figure, it should be noted that the same reference numerals designate components even when the same or equivalent components are shown in other figures. Furthermore, in describing exemplary embodiments of the invention, detailed descriptions of well-known features or functions will be omitted to avoid unnecessarily obscuring the spirit of the invention.

[0036] In describing the components of various exemplary embodiments of the present invention, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are used only to distinguish one component from another, and they do not limit the nature, order, or sequence of the components. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various exemplary embodiments of the present invention pertain. These terms, as defined in commonly used dictionaries, should be understood to have a meaning equivalent to that in the context of the relevant technical field, and should not be understood to have an ideal or overly formal meaning, unless expressly defined as such in this application.

[0037] The following will refer to Figures 1 to 6 The embodiments of the present invention will be described in detail below.

[0038] Figure 1 This is a block diagram of an auxiliary vehicle steering device according to various exemplary embodiments of the present invention.

[0039] refer to Figure 1 According to various exemplary embodiments of the present invention, the device for assisting vehicle steering may include: a turning direction recognizer 200 and a tire drive controller 500, wherein the turning direction recognizer 200 uses a steering angle controlled by a handle to identify the turning direction of the tires steering the vehicle; the tire drive controller 500 determines the tires to which a first driving force is applied (which is used to generate a steering assist torque for the turning direction identified by the assist tire steering) and the tires to which a second driving force is applied (which is used to counteract the first driving force so that the forward / reverse force of the vehicle remains 0), and controls drive motors disposed in the tires to generate the first driving force and the second driving force, respectively.

[0040] The turning direction recognizer 200 can identify whether the tire is turning right or left based on changes in the steering angle of the control handle.

[0041] In other words, since the tires applying the first driving force and the tires applying the second driving force are determined differently by the tire drive controller 500 according to the turning direction, the turning direction recognizer 200 can identify whether the vehicle turns right first or left first.

[0042] Therefore, the present invention is configured to generate a steering assist torque by means of the driving force of the tires during steering operations in a parking state that requires a large steering torque, and may further include a stop determiner 100 that determines in advance whether the vehicle has stopped by utilizing the vehicle's wheel speed.

[0043] The stop determiner 100 can determine whether the vehicle is in a stopped state based on whether the wheel speed of the tires obtained from the wheel speed sensors installed on the vehicle is 0, or based on whether the gear information of the automatic transmission obtained from the vehicle's electronic control unit (ECU) corresponds to a parking state.

[0044] When steering is performed using electric assisted steering (MDPS), the steering motor must generate steering torque that causes the tires to turn at a turning angle, and must apply steering torque to the tires to turn in the steering direction.

[0045] Therefore, as Figure 3 and Figure 4 As shown, in order to generate the steering torque that turns the tire, a steering motor is installed on one side of the tire to generate the steering torque that turns the tire when the handle is moved.

[0046] therefore, Figure 3 and Figure 4 An example of a tire configured for a four-wheel independent steering vehicle (where all four tires can be independently steered and driven). Thus, each tire may be equipped with a steering motor 10 and a drive motor 20, the steering motor 10 generating a steering torque for turning the tire in the steering direction, and the drive motor 20 generating a forward / reverse driving force for the tire.

[0047] Figure 3 and Figure 4 The diagram shows a steering motor 10 located on one side of the tire and a drive motor 20 located inside the tire. Furthermore, a kingpin is obliquely connected to one side of the tire as a steering shaft for transmitting steering inputs from the handle to the tire. Therefore, since both the kingpin and the steering motor must be located on one side of the tire, there are space limitations in increasing the size of the steering motor itself to increase its capacity.

[0048] In the current method, because the kingpin and steering motor are tilted to one side of the tire, the steering torque applied to the tire when turning by steering varies depending on the steering angle the tire is turning. That is, as the steering angle increases, the steering torque that must be applied to make the tire turn also increases.

[0049] In other words, such as Figure 2A As shown, at a steering angle of 0 ° In the case of zero turning, the tire deforms due to the vertical moment "W" (which is applied when the vehicle's gross vehicle weight (GVW) is pressed against the ground) and the ground's reaction force "R", and a specific compressive deformation δ0 occurs.

[0050] In other words, such as Figure 2BAs shown, even in a full turn with the steering angle at its maximum, the tire deforms due to the vertical moment "W" (which is applied when the vehicle's total vehicle weight (GVW) is pressed against the ground) and the ground's reaction force "R", resulting in a specific compressive deformation δ1.

[0051] Therefore, as the vehicle's steering angle increases, the vertical torque "W" exerted by the tires on the ground increases. That is, the vertical torque "W" exerted by the tires on the ground during a full turn is greater than the vertical torque "W" exerted by the tires on the ground during a zero turn. Consequently, the compressive deformation caused by tire deformation also increases.

[0052] In addition, such as Figure 2A and Figure 2B As shown, since the length of the torque arm r1 from the kingpin to the center of the tire is longer in a full turn than the length of the torque arm r0 from the kingpin to the center of the tire in a zero turn, the vertical torque also increases, and the steering torque (or kingpin torque) required to steer the tire also increases.

[0053] Typically, when a vehicle is turning, the steering torque required to turn when the vehicle is stationary (when the vehicle is affected by the coefficient of static friction) is higher than the steering torque required to turn when the vehicle is moving (when the vehicle is affected by the coefficient of dynamic friction), and a higher steering torque is required to meet the steering torque requirement.

[0054] Therefore, the size of the steering motor must also be increased because the steering motor must be able to generate the steering torque required to turn the tires. This is because the steering motor must be able to generate the steering torque required for a full turn when the vehicle is stationary (at which point the maximum steering torque is required).

[0055] Considering that the steering motor does not always require the maximum amount of steering torque, the present invention only uses the steering torque generated by the steering motor 10 to provide the steering torque required for the steering operation of the vehicle. However, when a steering torque exceeding the limit steering torque that can be generated by the steering motor is required (for example, when making a left or right turn at the maximum steering angle while the vehicle is stationary, i.e., in a full turn), as shown in Equation 1, the insufficient steering torque is supplemented by the driving force generated by the drive motor 20 located on the tire.

[0056] [Equation 1]

[0057] Required steering torque = Steering torque + (Motor shaft offset × Driving force)

[0058] Therefore, as Figure 4As shown, the driving force generated by the drive motor 20 is applied at a position at a distance corresponding to the offset of the motor shaft from the rotary motor shaft of the steering motor 10. Equation 1 represents the steering assist torque that helps the tires to turn by the product of the "motor shaft offset" and the "driving force".

[0059] In this way, since the required steering torque for a portion of the tire turning is provided by the drive force of the drive motor 20 by performing control, the steering torque that must be generated by the steering motor 10 can be reduced without increasing the weight and cost of the steering motor. Furthermore, the installation space in the tire's internal area can be minimized due to the reduction in the size of the steering motor.

[0060] Furthermore, the tire drive controller 500 can determine the tire to which a first driving force is applied (which is used to generate a steering assist torque that causes the tire to turn in the direction of the turn identified by the turn direction recognizer 200), and can generate the first driving force to assist the tire in turning by controlling the drive motor 20 set on the determined tire.

[0061] like Figure 5A and Figure 5B As shown, the tire drive controller 500 can: as the tire to which a first driving force is applied, and with the turning direction of the tire steering as a reference, determine the outer front wheel of the vehicle as the tire to which a positive (+) driving force is applied, and determine the inner front wheel of the vehicle as the tire to which a negative (-) driving force is applied.

[0062] Accordingly, the positive (+) driving force generated by the drive motor 20 refers to the power that makes the tire rotate forward, and the negative (-) driving force refers to the power that makes the tire rotate backward.

[0063] Since the rotation center of the torque arm is generally located inside the vehicle, the positive (+) driving force applied to the tire causes positive toe-in, and the negative (-) driving force applied to the tire causes negative toe-in.

[0064] Accordingly, the outer front wheel must have positive toe-in relative to the turning direction, while the inner front wheel must have negative toe-in, in order to generate a steering assist torque to turn the tires in the turning direction. The drive controller can execute control to apply positive (+) driving force to the outer front wheel and negative (-) driving force to the inner front wheel.

[0065] Correspondingly, since the tire drive controller 500 only uses the driving force of the drive motor to assist a portion of the steering torque when the steering angle is large, such as in a full turn when the vehicle is stationary, the vehicle must remain stationary.

[0066] Accordingly, the tire drive controller 500 can determine the tire to which a second driving force is applied, the second driving force being used to keep the vehicle stationary by counteracting the first driving force applied to the tire to generate steering assist torque, and the tire drive controller 500 can generate a second driving force to keep the forward / reverse force of the vehicle at 0 by controlling the drive motor 20 set on the determined tire.

[0067] The tire drive controller 500 can: as the tire to which a second driving force is applied, based on the turning direction of the tire steering, determine the inner rear wheel of the vehicle as the tire to which a positive (+) driving force is applied, and determine the outer rear wheel of the vehicle as the tire to which a negative (-) driving force is applied.

[0068] Accordingly, such as Figure 5A As shown, when a stationary vehicle is to turn to the left, a positive (+) driving force can be applied to the right front wheel and a negative (-) driving force can be applied to the left front wheel as the first driving force to generate steering assist torque; a positive (+) driving force can be applied to the left rear wheel and a negative (-) driving force can be applied to the right rear wheel as the second driving force to counteract the first driving force so that the forward / reverse force remains 0.

[0069] Accordingly, such as Figure 5B As shown, when a stationary vehicle is to turn to the right, a positive (+) driving force can be applied to the left front wheel and a negative (-) driving force can be applied to the right front wheel as the first driving force to generate steering assist torque; a positive (+) driving force can be applied to the right rear wheel and a negative (-) driving force can be applied to the left rear wheel as the second driving force to counteract the first driving force so that the forward / reverse force remains 0.

[0070] Furthermore, the length of the torque arm varies depending on the steering angle at which the tire is turning. When the steering torque generated by the steering motor is applied to the tire as it turns, the torque produced varies with the change in the length of the torque arm.

[0071] Accordingly, the present invention may further include: a torque arm calculator 300, which uses the magnitude of the steering angle of the operating handle to determine the length of the torque arm that changes as the tire turns.

[0072] The torque arm calculator 300 can predetermine data representing the incremental relationship between steering angle and torque arm by utilizing the vehicle's specification characteristics (including the mounting positions of the kingpin and steering motor, as well as the offset of the motor shaft), and can store this data in a storage unit such as a memory.

[0073] Accordingly, when the steering angle increases by maneuvering the steering, the torque arm calculator can identify the length of the torque arm that matches the steering angle based on data stored in memory or the like.

[0074] Furthermore, the present invention may further include: a steering assist determiner 400, which determines, based on the size of the steering angle, the magnitude of the required steering torque needed to turn the tires in the left or right direction when the vehicle is stationary, and when the required steering torque is greater than the limit steering torque generated by the steering motor, the steering assist determiner 400 determines to use the driving force generated by the drive motor to assist a portion of the required steering torque.

[0075] When turning left or right by manipulating the steering wheel while the vehicle is stationary, both the length of the torque arm and the vertical torque can increase, thus increasing the steering torque required for the vehicle's wheels to turn. Therefore, the required steering torque may need to exceed the limit steering torque that can be generated by the steering motor.

[0076] Accordingly, when the required steering torque exceeds the limit steering torque, the steering assist determiner 400 can determine a portion of the required steering torque that can be handled by the tire drive controller 500. In this way, when the steering assist determiner 400 determines that a portion of the required steering torque should be handled by the drive motor, the tire drive controller 500 can generate steering assist torque.

[0077] Furthermore, the steering assist determiner 400 can determine the ratio of the steering torque generated by the steering motor 10 to the steering assist torque generated by the drive motor 20 in the required steering torque.

[0078] Accordingly, the proportion of steering assist torque generated by the drive motor can be increased, but the steering assist torque generated by the driving force of the drive motor is generated in a secondary manner, so the drive motor does not bear an excessive proportion of the required steering torque.

[0079] Accordingly, the steering assist determiner 400 can be configured such that the proportion of the steering assist torque generated by the drive motor is less than 10% of the total required steering torque needed to turn the tire.

[0080] Furthermore, as the steering angle increases, the steering assist determiner 400 can match the required steering torque needed to steer the tires to the right or left while stationary with the steering angle. The matching result can be stored in a memory, and the required steering torque can be determined from the memory using the steering angle.

[0081] Furthermore, by storing the ratio and magnitude of the steering torque generated by the drive motor together with the required steering torque in the memory via the tire drive controller, the steering assist determiner 400 can control the steering torque generated by the steering motor and the steering assist torque generated by the drive motor by simply recognizing the magnitude of the steering angle.

[0082] Next, we will refer to Figure 6 Methods for controlling the steering of an assisted vehicle according to various exemplary embodiments of the present invention are described.

[0083] Figure 6 This is a schematic diagram of a method for controlling the steering of an assisted vehicle according to various exemplary embodiments of the present invention.

[0084] refer to Figure 6 According to various exemplary embodiments of the present invention, a method for controlling assisted vehicle steering may include: a turning direction identification step S200 and a tire drive control step S500, wherein the turning direction identification step S200 identifies the turning direction of the tires steering the vehicle by using a steering angle controlled by a handle; and the tire drive control step S500 determines the tires to which a first driving force (which is used to generate a steering assist torque for the turning direction identified by the assisted tire steering) is applied and the tires to which a second driving force (which is used to counteract the first driving force so that the forward / reverse force of the vehicle remains 0) is applied, and controls the drive motors provided on each tire to generate the first driving force and the second driving force respectively.

[0085] The turning direction recognition step S200 may include a step that identifies whether the turning direction of the tire is a right turn or a left turn based on the change in the steering angle of the control handle.

[0086] In this way, based on the turning direction of the tire identified in the turning direction identification step S200, the tire applying the first driving force and the tire applying the second driving force can be determined in the tire drive control step S500.

[0087] Accordingly, the present invention may further include a vehicle stop determination step S100, which determines whether the vehicle has stopped by utilizing the vehicle's wheel speed before identifying a change in steering angle in the turning direction identification step S200. In other words, the present invention is applicable to supplementing steering torque during steering in a stopped state requiring large steering torque, and first determining whether the vehicle has stopped.

[0088] Furthermore, the tire drive control step S500 may include steps such as determining a tire to which a first driving force (which is used to generate a steering assist torque that causes turning in the turning direction identified by the turning direction recognizer) is applied, and generating the first driving force to assist the tire in turning by controlling a drive motor provided on the determined tire.

[0089] The tire drive control step S500 may include the step of determining the inner rear wheel of the vehicle as the tire applying a second driving force, based on the turning direction of the tire steering, as the tire applying a positive (+) driving force, and determining the outer rear wheel of the vehicle as the tire applying a negative (-) driving force.

[0090] Accordingly, when a positive (+) driving force is applied to the outer front wheel, the outer front wheel has positive toe-in, and when a negative (-) driving force is applied to the inner front wheel, the inner front wheel has negative toe-in, thereby generating a steering assist torque that makes the tire turn in the direction the tire wants to turn.

[0091] Furthermore, the tire drive control step S500 may include steps such as determining a tire to which a second driving force (which is used to counteract the first driving force applied to the tire to generate steering assist torque and keep the vehicle stationary) is applied so that the vehicle remains stationary even when the tire is turning, and controlling the drive motor set on the determined tire to keep the overall forward / reverse force of the vehicle at 0.

[0092] To achieve this, the tire drive control step S500 may include the step of determining the inner rear wheel of the vehicle as the tire applying a second driving force, based on the turning direction of the tire steering, as the tire applying a positive (+) driving force, and the outer rear wheel of the vehicle as the tire applying a negative (-) driving force.

[0093] Accordingly, such as Figure 5A and Figure 5B As shown, when the vehicle is stationary, since the driving force applied to the tires to generate steering assist torque is applied in opposite directions to the front and rear wheels on the same side, the forward / reverse force applied to the entire vehicle can be kept at 0, thus keeping the vehicle stationary during steering.

[0094] Furthermore, the present invention may further include: a torque arm calculation step S300, which, after the turning direction identification step S200, determines the length of the torque arm that changes when the tire turns by utilizing the size of the steering angle.

[0095] The torque arm calculation step S300 may include steps such as pre-determining data representing the incremental relationship between the steering angle and the torque arm by utilizing the vehicle's specification feature values ​​(including the mounting positions of the kingpin and the steering motor, as well as the offset of the motor shaft), storing the data in a storage unit such as a memory, and determining and identifying the length of the torque arm that matches the size of the steering angle based on the data stored in the memory, etc.

[0096] Furthermore, the present invention may further include: a steering assist determination step S400, which determines the magnitude of the required steering torque needed to turn the tires in the left or right direction when the vehicle is stationary, based on the magnitude of the steering angle, and determines to use the driving force generated by the drive motor to assist a portion of the required steering torque when the required steering torque is greater than the limit steering torque generated by the steering motor.

[0097] Accordingly, the steering assist determination step S400 may include a step of determining a portion of the required steering torque that can be handled by the tire drive control step S500 when the required steering torque exceeds the limit steering torque.

[0098] In this way, when a portion of the required steering torque to be borne by the drive motor is determined in the steering assist determination step S400, steering assist torque can be generated in the tire drive control step S500.

[0099] In addition, the steering assist determiner S400 may include a step of determining the ratio of the steering torque generated by the steering motor to the steering assist torque generated by the drive motor in the required steering torque.

[0100] Furthermore, the steering assist determination step S400 may include the following steps: as the steering angle increases, matching the required steering torque needed to steer the tires to the right or left in a stationary state with the steering angle, storing the matching result in a memory, and determining the required steering torque by utilizing the steering angle through the memory.

[0101] Furthermore, the steering assist determination step S400 may include a step in which the ratio and magnitude of the steering torque generated by the drive motor are stored in a memory along with the desired steering torque by the tire drive controller, so that the steering torque generated by the steering motor and the steering assist torque generated by the drive motor can be controlled by simply identifying the magnitude of the steering angle.

[0102] The present invention can control the steering torque so that it can be supplemented and provided by the driving force of the drive motor to make the tire turn, thereby without increasing the steering torque that must be generated by the steering motor, thereby reducing the increase in weight and cost of the steering motor.

[0103] Furthermore, the present invention can utilize the steering torque of the steering motor, which is generated by the cooperation of the steering motor with the drive motor, to turn the tire, thereby minimizing the increase in weight and volume of the steering motor, and thus allowing for a margin when designing the encapsulation of the tire's internal area.

[0104] Furthermore, the present invention can provide various effects that can be directly or indirectly identified.

[0105] The above description is a simple example of the technical spirit of the present invention, and those skilled in the art can make various corrections and modifications to the present invention without departing from its basic characteristics, based on the various exemplary embodiments thereof.

[0106] Furthermore, terms relating to control devices, such as "controller," "control unit," "control device," or "control module," refer to hardware devices including a memory and a processor configured to execute one or more steps interpreted as an algorithmic structure. The memory stores the algorithmic steps, and the processor executes these steps to perform one or more processes of methods according to various exemplary embodiments of the invention. A control device according to an exemplary embodiment of the invention can be implemented using non-volatile memory and a processor configured to store algorithms for controlling the operation of various components of a vehicle or data regarding software commands for executing the algorithms, the processor being configured to perform the aforementioned operations using the data stored in the memory. The memory and processor can be separate chips. Alternatively, the memory and processor can be integrated into a single chip. The processor can be implemented as one or more processors. The processor can include various logic and arithmetic circuits, can process data according to a program provided from the memory, and can generate control signals based on the processing results.

[0107] The control device may be at least one microprocessor operated by a predetermined program, which may include a series of commands for performing the methods disclosed in the various exemplary embodiments of the present invention described above.

[0108] The invention described above can also be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium is any data storage device that can store data that can subsequently be read by a computer system. Examples of computer-readable recording media include hard disk drives (HDDs), solid-state drives (SSDs), silicon disk drives (SDDs), read-only memory (ROM), random access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and implementations as carrier waves (e.g., transmission over the Internet).

[0109] In various exemplary embodiments of the present invention, each of the above steps may be performed by a control device, and the control device may be configured by multiple control devices or an integrated single control device.

[0110] In various exemplary embodiments of the present invention, the control device may be implemented in hardware or software, or in a combination of hardware and software.

[0111] For ease of interpretation and precise definition of the appended claims, the terms “upper,” “lower,” “inner,” “outer,” “above,” “below,” “upward,” “downward,” “front,” “back,” “inner,” “outer,” “inward,” “outer,” “internal,” “external,” “inner side,” “outer side,” “forward,” and “backward” are used with reference to the positions of these features shown in the accompanying drawings to describe features of the exemplary embodiments. It will be further understood that the term “connection” or its derivatives refer to both direct and indirect connections.

[0112] The foregoing description of specific exemplary embodiments of the invention is for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many changes and variations are possible in accordance with the foregoing teachings. The exemplary embodiments were chosen and described to explain the specific principles of the invention and its practical application, thereby enabling others skilled in the art to implement and utilize various exemplary embodiments of the invention, as well as their various alternatives and modifications. The scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A device for assisting vehicle steering, the device comprising: A turning direction recognizer, configured to identify the turning direction of the tires of a vehicle by using the steering angle controlled by a control handle; and A tire drive controller is configured to: determine a tire to which a first driving force is applied and a tire to which a second driving force is applied, and control drive motors provided on each tire to generate a first driving force and a second driving force, wherein the first driving force is used to generate a steering assist torque to assist the tire to turn to the identified turning direction, and the second driving force is used to counteract the first driving force to keep the forward / reverse force of the vehicle at 0. The tire drive controller is configured as follows: As the tires that apply the first driving force, the outer front tires of the vehicle are defined as the tires that apply the positive (+) driving force, and the inner front tires of the vehicle are defined as the tires that apply the negative (-) driving force, based on the turning direction of the tires. As the tires that apply the second driving force, the inner rear tires of the vehicle are designated as the tires that apply the positive (+) driving force, and the outer rear tires of the vehicle are designated as the tires that apply the negative (-) driving force, based on the turning direction of the tires.

2. The device for assisting vehicle steering according to claim 1, further comprising: A stop determinant is configured to determine in advance whether the vehicle has stopped by utilizing the vehicle's wheel speed.

3. The device for assisting vehicle steering according to claim 1, wherein, The tire drive controller is configured to perform control to apply a positive (+) driving force as a first driving force to the right front wheel of the vehicle and a negative (-) driving force as a first driving force to the left front wheel of the vehicle when turning the vehicle from a stopped state to a left turn, and to apply a positive (+) driving force as a second driving force to the left rear wheel of the vehicle and a negative (-) driving force as a second driving force to the right rear wheel of the vehicle.

4. The device for assisting vehicle steering according to claim 1, wherein, The tire drive controller is configured to perform control to apply a positive (+) driving force as a first driving force to the left front wheel of the vehicle and a negative (-) driving force as a first driving force to the right front wheel of the vehicle when turning the vehicle from a stationary state to a right turn, and to apply a positive (+) driving force as a second driving force to the right rear wheel of the vehicle and a negative (-) driving force as a second driving force to the left rear wheel of the vehicle.

5. The device for assisting vehicle steering according to claim 1, further comprising: The torque arm calculator is configured to: pre-determine data representing the incremental relationship between steering angle and torque arm using vehicle specification characteristics, store the data in a memory, and use the steering angle to identify the length of the torque arm that changes when the tires turn using the memory. The vehicle specification characteristics include the mounting positions of the kingpin and steering motor, as well as the offset of the motor shaft.

6. The device for assisting vehicle steering according to claim 1, further comprising: The steering assist determiner is configured to: determine the required steering torque needed to turn the tires in the left or right direction when the vehicle is stationary, based on the steering angle; and when the required steering torque is greater than the limit steering torque generated by the steering motor, determine a portion of the required steering torque to be assisted by a first driving force and a second driving force generated by the drive motor.

7. The device for assisting vehicle steering according to claim 6, wherein, The steering assist determiner is configured to determine the ratio of the steering torque generated by the steering motor to the steering assist torque generated by the drive motor in the required steering torque.

8. A method for controlling the steering of an assisted vehicle, the method comprising: The turning direction recognition step uses the steering angle controlled by the handle to identify the turning direction of the vehicle's tires. The tire drive control step identifies the tire to which a first driving force is applied and the tire to which a second driving force is applied, and controls the drive motors provided on each tire to generate the first driving force and the second driving force respectively. The first driving force is used to generate a steering assist torque to assist the tire to turn to the identified turning direction, and the second driving force is used to counteract the first driving force so that the forward / reverse force of the vehicle remains at 0. The tire drive control steps include: As the tires that apply the first driving force, the outer front tires of the vehicle are defined as the tires that apply the positive (+) driving force, and the inner front tires of the vehicle are defined as the tires that apply the negative (-) driving force, based on the turning direction of the tires. As the tires that apply the second driving force, the inner rear tires of the vehicle are designated as the tires that apply the positive (+) driving force, and the outer rear tires of the vehicle are designated as the tires that apply the negative (-) driving force, based on the turning direction of the tires.

9. The method of claim 8, further comprising: The vehicle stop determination step determines whether the vehicle has stopped by utilizing the vehicle's wheel speed before identifying a change in steering angle in the turning direction recognition step.

10. The method of claim 8, further comprising: The steering assist determination step, prior to the tire drive control step, determines the required steering torque needed to turn the tires in the left or right direction while the vehicle is stationary, based on the steering angle. When the required steering torque exceeds the limit steering torque generated by the steering motor, a portion of the required steering torque is determined to be assisted by the first and second driving forces generated by the drive motor.

11. The method according to claim 10, wherein, The steering assist determination step includes: Determine the ratio of the steering torque generated by the steering motor to the steering assist torque generated by the drive motor in the required steering torque.

12. The method of claim 8, further comprising: The control is executed such that when turning a stationary vehicle to turn left, a positive (+) driving force as a first driving force is applied to the right front wheel of the vehicle and a negative (-) driving force as a first driving force is applied to the left front wheel of the vehicle, and a positive (+) driving force as a second driving force is applied to the left rear wheel of the vehicle and a negative (-) driving force as a second driving force is applied to the right rear wheel of the vehicle.

13. The method of claim 8, further comprising: The control is executed such that when turning a stationary vehicle to turn right, a positive (+) driving force as a first driving force is applied to the left front wheel of the vehicle and a negative (-) driving force as a first driving force is applied to the right front wheel of the vehicle, and a positive (+) driving force as a second driving force is applied to the right rear wheel of the vehicle and a negative (-) driving force as a second driving force is applied to the left rear wheel of the vehicle.

14. The method of claim 8, further comprising: By pre-determining data representing the incremental relationship between steering angle and torque arm using the vehicle's specification characteristics, the data is stored in a memory, and the length of the torque arm that changes when the tires turn is identified through the memory using the size of the steering angle. The vehicle's specification characteristics include the mounting positions of the kingpin and steering motor, as well as the offset of the motor shaft.

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