Steering feel assistance device for steer-by-wire system and method thereof

Abstract

The present disclosure relates to a steering assist apparatus of a steer-by-wire system and a method thereof. A steering feel assist apparatus of a steer-by-wire (SBW) system can include a disc configured to rotate together with a steering shaft, a cam coupled to an actuator and configured to receive a rotational force of the actuator to eccentrically rotate, and a brake arm configured to selectively come into frictional contact with an outer circumferential surface of the disc to provide a predetermined frictional force in a positive rotational direction of the disc when the brake arm rotates in conjunction with rotation of the cam.

Description

Technical Field

[0001] This invention relates to a steering feel assist device for a steer-by-wire (SBW) system, which can selectively assist the steering feel of the steering wheel. Background Technology

[0002] A steer-by-wire (SBW) system is a steering system in which the mechanical connection of the steering wheel is separated from the vehicle's drive wheels, and the rotation signal of the steering wheel is input through an electronic control unit (ECU), and the steering motor connected to the drive wheels operates based on the input rotation signal to steer the vehicle.

[0003] The steer-by-wire system can increase the degree of freedom in the layout depending on the configuration of the steering system, can improve the fuel ratio, and can eliminate disturbances from the reverse input of the wheels by removing the mechanical connection structure of the existing steering system.

[0004] At the same time, since the mechanical connection structure is interrupted and the steering information required by the driver cannot be properly fed back, additional safety elements are needed when preparing existing MDPS.

[0005] For example, representative features required for steering feel devices may include: a fault-tolerant function that allows operation of the steering feel device even when the steering angle sensor malfunctions; a function to prevent sudden loss of steering feel; and a function to prevent the steering wheel from rotating freely even when the system power is turned off.

[0006] In a more detailed description, since the system may fail to recognize the driver's steering input when the steering angle sensor fails, the vehicle may behave erroneously. Therefore, a fault operating system is required. Thus, a triple module redundancy or 2oo2 DFS scheme is used as one of the fault operating systems.

[0007] In terms of steering feel, this problem can be prevented because if the steering feel is suddenly lost when the driver makes a large steering input, the vehicle may become unstable (oversteering, etc.).

[0008] To achieve this, measures have been proposed to provide a fault operating system by adding redundancy to the steering feel motor (such as a dual-winding motor).

[0009] Furthermore, during vehicle power failure (starting), no force is applied to the steering wheel. Therefore, when the steering wheel rotates freely in the power-off state and its position differs significantly from that of the load-bearing wheels, the system will be activated (started), and the load-bearing wheels may suddenly move due to their arrangement.

[0010] Therefore, one approach has been mentioned that adds a stop device configured to prevent steering wheel rotation or inserts additional logic for arranging it during system engagement.

[0011] However, employing a fault-tolerant operating system configured to prevent the steering feel motor from losing its grip could be a solution, but this would significantly increase the cost of the components.

[0012] Furthermore, the need for additional devices to prevent the steering wheel from rotating during system power-off also contributes to increased manufacturing costs, and because the steering wheel rotation may be locked when this device malfunctions, fail-safe features to address this issue are also necessary.

[0013] The information included in the background section of this invention is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission of prior art known to those skilled in the art or as any form of advice. Summary of the Invention

[0014] Various aspects of the present invention are intended to provide steering feel assist devices for SBW systems that selectively assist the steering feel of the steering wheel.

[0015] According to one aspect of the invention, a steering feel aid for a steer-by-wire (SBW) system includes: a disc configured to rotate with a steering shaft; a cam engaged with an actuator and configured to receive rotational force from the actuator to rotate eccentrically; and a brake arm configured to selectively frictionally contact an outer peripheral surface of the disc to provide a predetermined frictional force in the forward rotation direction of the disc as the brake arm rotates in conjunction with the rotation of the cam.

[0016] The rotating shaft can be located at one end of the brake arm, and the cam can contact the middle of the brake arm, so that when the cam rotates eccentrically and selectively rubs against the outer peripheral surface of the disc, the second end of the brake arm rotates about the rotating shaft in a direction that approaches or moves away from the disc.

[0017] The steering feel aid may also include a pressure spring, mounted on the housing and configured to provide a spring force to the brake arm in the direction of rotation of the brake arm toward the disc at the second end of the brake arm.

[0018] The brake arm may include a first brake arm and a second brake arm respectively disposed on a first side and a second side of the cam. The rotation axis of one end of the first brake arm and one end of the second brake arm may be located in a direction opposite to the disk relative to the cam; and the opposite ends of the first brake arm and the opposite ends of the second brake arm are respectively located on one side and the opposite side of the disk.

[0019] The opposite ends of the brake arms can make frictional contact with any point of the cam's rotation radius, and the opposite ends of the brake arms contact the outer peripheral surface of the disc while drawing a tangent.

[0020] The disc can be coupled to the steering shaft, the cam can be mounted on one side of the disc, and the rotation axes of the disc, cam, and brake arm can be in the same direction and parallel to each other.

[0021] The brake arm can selectively make frictional contact with the disc in the eccentric direction of the cam; the second ends of the first brake arm and the second ends of the second brake arm can both release the frictional contact with the disc in the first eccentric direction, in which the cam is eccentric towards the first and second rotation axes in its entire rotating part; only the opposite ends of the first brake arm can make frictional contact with the disc in the second eccentric direction in which the cam is eccentric towards the second brake arm; only the opposite ends of the second brake arm can make frictional contact with the disc in the third eccentric direction in which the cam is eccentric towards the first brake arm; and the second ends of the first brake arm and the second ends of the second brake arm can both make frictional contact with the disc in the fourth eccentric direction in which the cam is eccentric towards the disc.

[0022] The steering assist device may also include a return spring mounted on the housing and engaged with the cam, and configured to provide a spring force in the eccentric direction in which the cam rotates toward the disk.

[0023] The friction brush can be individually coupled to the second end of the brake arm to make frictional contact with the outer peripheral surface of the disc, and a friction pattern can be formed on the friction surface of the disc.

[0024] The steering feel assist device may further include: a steering angle sensor configured to detect the steering angle of the steering shaft; a steering feel motor configured to provide steering feel to the steering shaft; a steering motor coupled to a rack and configured to provide steering force to the rack; and a controller electrically connected to the steering angle sensor, the steering feel motor, the steering motor, and the actuator, and configured to selectively provide steering feel in the positive rotation direction of the steering shaft by controlling the operation of the steering feel motor or actuator based on the steering angle and the torque value of the steering motor.

[0025] When the absolute value of the target torque of the steering motor is equal to or greater than the absolute value of the threshold torque and the derivative of the absolute value of the target torque is greater than 0, or when the absolute value of the steering angle reaches the absolute value of the constraint angle corresponding to the endpoint of the steering angle, the controller can limit the rotation of the steering shaft by generating the maximum repulsive force in the steering motor.

[0026] After the steering motor generates maximum torque, the controller can maintain the absolute value of the target torque above the absolute value of the threshold torque, and determine the rotation direction of the disc when the absolute value of the steering angle is maintained above the absolute value of the constraint angle, wherein a predetermined friction force is provided; and the friction force can be provided by controlling the rotation of the cam through the actuator to make the disc rotate forward or backward through the brake arm.

[0027] When the target friction direction of the disc is opposite to its direction, the first brake arm can be made to rub against the disc by controlling the rotation of the cam, and the second brake arm can be released from friction contact with the disc in order to rub against the disc in the opposite direction of the disc rotation; and when the target constraint direction of the disc is positive, the second brake arm can be made to rub against the disc by controlling the rotation of the cam, and the first brake arm can be released from friction contact with the disc in order to rub against the disc in the positive direction of the disc rotation.

[0028] The controller can perform control to maintain the maximum repulsive force of the steering feel motor while providing frictional force to the steering wheel via the brake arm.

[0029] The controller can be configured to release the frictional contact with the disc by controlling the first brake arm and the second brake arm after the steering motor generates the maximum repulsive force, when the absolute value of the target torque is less than the absolute value of the threshold torque and the absolute value of the steering angle is less than the absolute value of the constraint angle.

[0030] The controller can perform control to cause the first and second brake arms to make frictional contact with the disc by controlling the rotation of the cam during vehicle start-up, thereby providing frictional force in the positive rotation direction of the disc.

[0031] Through these solutions, and various exemplary embodiments of the invention, additional steering feel is provided only for the direction of steering rotation, which is selectively limited by the disc frictional contact based on the change in the rotation angle of the cam, as controlled by the actuator.

[0032] Therefore, when the driver wants to feel a high load, the missing torque can be additionally provided to the steering feel motor, and when the driver suddenly performs a reverse operation of the steering wheel while the wheel is in a state of limiting unidirectional rotation, the reverse locking phenomenon of the steering wheel can be removed by allowing the steering wheel to rotate.

[0033] Furthermore, since steering sensitivity can be reduced by immediately providing friction to the driver and preventing sudden steering in the event of a steering motor malfunction during vehicle operation, it provides the driver with handling and driving safety, and can prevent excessive bidirectional rotation of the steering wheel without additional configuration or voltage application in the starting state.

[0034] The methods and apparatus of the present invention have other features and advantages, which will be more apparent from or set forth in more detail in the accompanying drawings, which are incorporated herein and in the following detailed description, and together serve to explain certain principles of the invention. Attached Figure Description

[0035] Figure 1This is an illustrative diagram showing the configuration of an SBW system according to various exemplary embodiments of the present invention, in which steering feel assistive devices are installed;

[0036] Figure 2 This is a diagram illustrating the configuration of a steering angle constraint device according to various exemplary embodiments of the present invention;

[0037] Figure 3 This is an illustrative diagram showing an operational state that provides frictional force to reverse the rotation of the steering shaft according to various exemplary embodiments of the present invention;

[0038] Figure 4 This is an illustrative diagram showing, by way of example, the operational state of providing frictional force to rotate the steering shaft in the positive direction according to various exemplary embodiments of the present invention;

[0039] Figure 5 This is an illustrative diagram showing, by way of example, the operational state of providing frictional force that causes bidirectional rotation of the steering shaft according to various exemplary embodiments of the present invention;

[0040] Figure 6 These are illustrations of configurations for mounting and removing friction brushes from and from the brake arm, and for forming friction patterns on the surface of the disc, according to various exemplary embodiments of the present invention; and

[0041] Figure 7 This is a flowchart illustrating the control process for limiting the steering angle according to various exemplary embodiments of the present invention.

[0042] It should be understood that the accompanying drawings are not necessarily drawn to scale and present slightly simplified representations of various features illustrating the basic principles of the invention. Specific design features of the invention as included herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific intended application and environment of use.

[0043] In the accompanying drawings, reference numerals throughout the various figures refer to the same or equivalent parts of the invention. Detailed Implementation

[0044] 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 in the appended claims.

[0045] Various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0046] The steering feel assist device of the SBW system according to various exemplary embodiments of the present invention includes a disc 10, a cam 20 and a brake arm 30.

[0047] Reference Figure 1 In the detailed description of the present invention, firstly, the disk 10 rotates together with the steering shaft 11, and for example, the disk 10 is assembled and coupled to the steering shaft 11, and rotates together with the steering shaft 11 in a constrained state. The steering shaft 11 may be a cylindrical shaft that rotates together with the steering wheel 12.

[0048] The cam 20 receives the rotational force of the actuator 21 to rotate eccentrically and can be positioned on one side of the disk 10.

[0049] Furthermore, when the brake arm 30 rotates in conjunction with the rotation of the cam 20, the brake arm 30 selectively engages in frictional contact with the outer peripheral surface of the disc 10 to provide a predetermined frictional force in the positive rotational direction of the disc 10. Here, the predetermined frictional force can be a torque of approximately 5 Nm.

[0050] The brake arm 30 extends along its longitudinal direction, and a rotating shaft 31 is disposed at one end thereon. The cam 20 contacts the middle of the brake arm 30. Thus, when the cam 20 rotates, the opposite ends of the brake arm 30 rotate about the rotating shaft 31 in a direction in which the opposite ends of the brake arm 30 approach or move away from the disc 10. Therefore, the opposite ends of the brake arm 30 contact or release contact with the outer peripheral surface of the disc 10.

[0051] In a more detailed description of the configuration of the brake arm 30, the brake arm 30 includes a first brake arm 30a disposed on one side of the cam 20 and a second brake arm 30b disposed on the opposite side of the cam 20.

[0052] The rotation axis 31 of the first brake arm 30a and the rotation axis 31 of the second brake arm 30b are positioned relative to the cam 20 in a direction opposite to the disc 10, and the opposite ends of the first brake arm 30a and the opposite ends of the second brake arm 30b are located on one side and opposite side of the disc 10.

[0053] Therefore, the rotation shaft 31 of the first brake arm 30a and the rotation shaft 31 of the second brake arm 30b can be installed independently, and the axial direction of the rotation shaft 31 can be the same as the axial direction of the disc 10 and the cam 20 so as to be parallel to each other.

[0054] Furthermore, when the disc 10 rotates from the opposite end of the brake arm 30 to one end of the brake arm 30, the rotation of the disc 10 must be restricted, and when the disc 10 rotates from one end of the brake arm 30 to the opposite end of the brake arm 30, the rotation of the disc 10 must be permitted.

[0055] Therefore, it is necessary to adjust the position of the disc 10 in frictional contact with the opposite ends of the brake arm 30 to a specific position, and in various exemplary embodiments of the present invention, the opposite ends of the brake arm 30 may rub against a point on the outer peripheral surface of the disc 10 facing the cam 20.

[0056] More specifically, in various exemplary embodiments of the invention, the opposing ends of the brake arms 30 must make frictional contact with any point on the radius of rotation of the cam 20, and these opposing ends contact the outer peripheral surface of the disc 10 while drawing a tangent. Therefore, a steering feel can be provided while the opposing ends of the brake arms 30 are in more secure frictional contact with the outer peripheral surface of the disc 10.

[0057] That is, such as Figure 3 As shown, when the cam 20 is eccentrically rotated to the right, the opposite end of the left first brake arm 30a is in frictional contact with the outer peripheral surface of the disc 10, and frictional force is applied to the disc 10 in the opposite direction (counterclockwise), making it difficult for the steering wheel 12 to pivot in the opposite direction. However, in the current situation, because the friction for the forward rotation of the disc 10 is not high, the steering wheel 12 can easily rotate in the forward direction when the driver suddenly turns forward.

[0058] Similarly, such as Figure 4 As shown, when the cam 20 is eccentrically rotated to the left, the opposite end of the right second brake arm 30b is in frictional contact with the outer peripheral surface of the disc 10, and frictional force is applied to the positive direction (clockwise) of the disc 10, making it difficult for the steering wheel 12 to pivot in the forward direction. However, in the current situation, because the friction for the reverse rotation of the disc 10 is not high, the steering wheel 12 can easily rotate in the reverse direction if the driver suddenly reverses the steering.

[0059] Therefore, the present invention can selectively provide friction in the positive rotation direction of the steering shaft 11 by using a plurality of brake arms 30 disposed outside the disc 10, and the steering shaft 11 can easily rotate in the opposite direction when the friction is applied to the specific rotation direction of the steering shaft 11, and even if the driver suddenly performs a reverse steering operation, the steering wheel 12 will not lock because it can still rotate.

[0060] In addition, the present invention may also include a pressure spring 40, which is mounted on the housing 45 and provides elastic force to the opposite end of the brake arm 30 in the direction of rotation of the disc 10.

[0061] For example, since the pressure springs 40 are connected between the first brake arm 30a and the vehicle body and between the second brake arm 30b and the vehicle body respectively, if the cam 20 rotates eccentrically, the opposite ends of the brake arms 30 are pushed toward the disc 10 by the tension of the pressure springs 40, and thus the opposite ends of the brake arms 30 spaced apart from the disc 10 come into frictional contact with the disc 10, thereby restricting the unidirectional rotation of the disc 10.

[0062] In the present manner, in various exemplary embodiments of the invention, the brake arm 30 is configured to selectively engage with the disc 10 in an eccentric direction relative to the cam 20.

[0063] For example, such as Figure 2 As shown, because the opposite ends of the first brake arm 30a and the opposite ends of the second brake arm 30b both release frictional contact with the disc 10 in the first eccentric direction, in the first eccentric direction, the cam 20 is eccentric to the rotation axis 31 in the entire rotating part of the cam 20, and the disc 10 rotates freely clockwise or counterclockwise, thereby the steering wheel 12 can pivot to the left and to the right.

[0064] In addition, such as Figure 3 As shown, in the second eccentric direction connected to the first eccentric direction and cam 20 eccentric towards the second brake arm 30b, only the opposite ends of the first brake arm 30a are in frictional contact with the disc 10, and thus, the counterclockwise rotation of the disc 10 is restricted, and the clockwise rotation of the disc 10 is allowed to restrict the leftward pivoting of the steering wheel 12.

[0065] In addition, such as Figure 5 As shown, in the fourth eccentric direction connected to the second eccentric direction and the cam 20 is eccentric towards the disc 10, the opposite ends of the first brake arm 30a and the opposite ends of the second brake arm 30b are in frictional contact with the disc 10, thereby restricting the clockwise and counterclockwise rotation of the disc 10 to restrict the leftward and rightward pivoting of the steering wheel 12.

[0066] In addition, such as Figure 4 As shown, in the third eccentric direction, which connects the first eccentric direction and the fourth eccentric direction and is eccentric to the first brake arm 30a, only the opposite end of the second brake arm 30b is in frictional contact with the disc 10; thus, clockwise rotation of the disc 10 is restricted, and counterclockwise rotation of the disc 10 is allowed to restrict rightward pivoting of the steering wheel 12.

[0067] In addition, the invention may also include a return spring 22, which is mounted on the housing 45 and provides elastic force to the cam 20 in the rotational direction eccentric to the disk 10.

[0068] For example, the return spring 22 can be a torsion spring, and with the return spring 22 mounted on the shaft of the cam 20, one end of the return spring 22 is coupled to the end of the cam 20 and the opposite end of the return spring 22 is fixed to the vehicle body, thus providing a spring force such that the cam 20 is located in the direction of the cam 20 eccentric towards the disc 10, i.e., the fourth eccentric direction.

[0069] In other words, when the voltage is not applied to either the steering motor 14 or the actuator 21, the cam 20 is eccentric in the fourth eccentric direction of the disc 10 by the elastic force of the return spring 22. Therefore, since the opposite ends of the first brake arm 30a and the opposite ends of the second brake arm 30b are in frictional contact with the disc 10, the leftward and rightward pivoting of the steering wheel 12 is restricted.

[0070] Of course, when the actuator 21 is operating normally, the operating force of the actuator 21 is higher than the spring force of the return spring 22, and therefore the eccentric direction of the cam 20 can be controlled according to the operation of the actuator 21.

[0071] At the same time, such as Figure 6 As shown, in various exemplary embodiments of the present invention, friction brushes 32 are respectively coupled to opposite ends of brake arms 30 to make frictional contact with the outer peripheral surface of the disc.

[0072] Furthermore, a friction pattern is formed on the outer peripheral surface of the disk 10. This friction pattern can have various shapes, such as grid shapes, wave shapes, and sawtooth shapes.

[0073] That is, when the friction surface of the friction brush 32 is worn and the friction force is reduced, only the friction brush 32 can be replaced for use, and the steering feel above the predetermined value can be maintained conveniently at low cost, and the friction force between the disk 10 and the friction brush 32 can be increased by forming a friction pattern on the outer peripheral surface of the disk 10.

[0074] Meanwhile, in various exemplary embodiments of the present invention, additional steering feel is generated by controlling the operation of the actuator 21 and the steering feel motor 14 by the controller 50 and providing frictional force in the steering rotation direction of the steering wheel 12.

[0075] To achieve this, in addition to the steering motor 14, the present invention may also include a steering angle sensor 13, a steering motor 16, and a controller 50.

[0076] The controller 50 according to various exemplary embodiments of the present invention can be implemented by an algorithm configured to control the operation of various components of a vehicle, a non-volatile memory configured to store data on software instructions for reproducing the algorithm, and a processor configured to perform the operations described below using the data stored in the memory. Here, the memory and processor can be implemented by separate chips. Alternatively, the memory and processor can be implemented by an integrated single chip. The processor can take the form of one or more processors.

[0077] Reference Figure 1 and Figure 2 In the detailed description, the steering angle sensor 13 is installed in the steering shaft 11 to detect the steering angle of the steering shaft 11, the steering feel motor 14 is installed to provide steering feel to the steering shaft 11, and the steering motor 16 is installed to provide steering force to the rack 15.

[0078] Furthermore, the torque values ​​(current values) of the steering angle sensor 13 and the steering motor 16 are input through the controller 50, and the operation of the steering feel motor 14 or actuator 21 is controlled based on the input steering angle and the torque value of the steering motor 16 to selectively provide steering feel in the positive rotation direction of the steering shaft 11.

[0079] For example, when the target torque T of the steering motor 16 target The absolute value is greater than or equal to the threshold torque T threshold The absolute value and the target torque T target The derivative of the absolute value is greater than 0, or the absolute value of the steering angle θ reaches the constraint angle θ corresponding to the endpoint of the steering angle. limit When the absolute value of the torque is reached, the controller 50 is configured to limit the rotation of the steering shaft 11 by generating a maximum repulsive force (soft lock) in the steering feel motor 14. Soft lock can be the maximum torque that can be output by the steering feel motor 14 to constrain the rotation of the steering shaft 11.

[0080] In other words, when it is determined that the steering wheel 12 is fully turned to either side and reaches the end of the steering angle, or when the tire steering angle cannot be further increased when the tire contacts the curb, only when the target current of the steering motor 16 increases to a value greater than the allowable current, the maximum current that may be output through the steering feel motor 14 is generated, thereby limiting the rotation of the steering shaft 11 (soft lock).

[0081] Furthermore, after the steering feel motor 14 generates maximum torque, the controller 50 sets the target torque T. target The absolute value remains at the threshold torque T threshold The absolute value is above and when the absolute value of the steering angle θ remains at the constraint angle θ limit When the absolute value is greater than or equal to the value of the friction force, the rotation direction of the disk 10 to which friction force is to be provided is determined.

[0082] Furthermore, by controlling the rotation of the cam 20 by the actuator 21, frictional force for the forward or reverse rotation of the disc 10 can be provided by the brake arm 30.

[0083] In detail, when the target constraint direction of the disc 10 is opposite to its direction, the rotation operation of the cam 20 is controlled to make the first brake arm 30a frictionally contact the disc 10, and the frictional contact between the second brake arm 30b and the disc 10 is released, thereby providing a steering feel of more than a predetermined value to make the disc 10 rotate in the opposite direction.

[0084] Furthermore, when the target constraint direction of the disc 10 is its positive direction, the second brake arm 30b is made to rub against the disc 10 by controlling the rotation operation of the cam 20, and the first brake arm 30a is released from the frictional contact with the disc 10, thereby providing a steering feel of more than a predetermined value to make the disc 10 rotate in the positive direction.

[0085] In other words, after the soft lock that first restricts the rotation of the steering shaft 11 by the steering feel motor 14, when the state of the end point of the steering angle is maintained or the target current of the steering motor 16 is further increased, the forward or reverse rotation of the wheel 10 is restricted by the rotation operation of the first brake arm 30a or the second brake arm 30b, thereby providing additional steering feel in the left or right pivoting direction of the steering wheel 12.

[0086] Meanwhile, while providing friction through the rotation of the brake arm 30 and the steering wheel 10, the controller 50 can perform control to maintain the maximum torque of the steering feel motor 14.

[0087] In other words, the driver is certain that it is difficult to rotate the steering angle by maintaining a soft-lock operation performed by the steering feel motor 14 while the steering feel is provided by applying friction to the disc 10 through the operation of the brake arm 30.

[0088] In addition, the controller 50 can control the rotation of the cam 20 during vehicle start-up to limit the forward and reverse rotation of the disc 10 when the first brake arm 30a and the second brake arm 30b are in frictional contact with the disc 10.

[0089] That is, when the vehicle is running, there needs to be a function to prevent the steering wheel 12 from rotating easily, and such as Figure 5 As shown, the cam 20 is operated such that the opposite ends of the first brake arm 30a and the opposite ends of the second brake arm 30b both come into frictional contact with the outer peripheral surface of the disc and the frictional force is increased, thereby preventing the steering wheel 12 from rotating easily.

[0090] In addition, the controller 50 monitors for faults in the steering motor 14 and actuator 21 during vehicle startup. When a fault is detected in the monitoring results of the steering motor 14 and actuator 21, the voltage applied to the steering motor 14 and actuator 21 is interrupted, and the fault is notified to the driver via voice or display to warn the driver.

[0091] Therefore, if the voltage applied to the steering feel motor 14 and actuator 21 is interrupted, the eccentric direction of the cam 20 rotates eccentrically in the direction facing the disc 10 by the spring force of the return spring 22. When the friction brushes 32 of the two brake arms 30 come into frictional contact with the outer peripheral surface of the disc 10, the frictional force increases, thereby limiting the rotation of the steering wheel 12.

[0092] At the same time, in reference Figure 7 In describing the process of providing steering feel to the steering wheel 12 using the steering feel assist device of the SBW system of the present invention, firstly, as Figure 5 As shown, when the vehicle is started and the power to the motor and actuator is cut off, both the first brake arm 30a and the second brake arm 30b are in frictional contact with the disc 10, and the bidirectional rotation of the disc 10 is restricted (S100).

[0093] However, when the vehicle's power is on and the power to the steering motor 14 and actuator 21 is on, it is determined whether a soft-lock operation of the steering angle is required by using the steering angle θ and the torque value of the steering motor 16 (S10).

[0094] That is, the controller 50 is configured to determine the target torque T of the steering motor 16. target The absolute value is greater than or equal to the threshold torque T threshold The absolute value and the target torque T target The derivative of the absolute value of the angle θ is greater than 0, or the absolute value of the steering angle θ is the constraint angle θ. limit When the absolute value exceeds the limit, the rotation of the steering shaft 11 is restricted by generating the maximum repulsive force (soft lock) in the steering feel motor 14 (S20).

[0095] Simultaneously, if the condition is not met in the determination result of step S10, a steering feel is generated with a torque less than the maximum repulsive force of the steering feel motor 14 and provided to the steering shaft 11 (S90). Therefore, the rotation of the disc 10 is controlled to be unrestricted by both the first brake arm 30a and the second brake arm 30b being spaced apart from the disc 10.

[0096] Simultaneously, after step S30, it is determined whether additional steering feel operation of the steering wheel is required by using the steering angle θ and the torque value of the steering motor 16 (S30).

[0097] In other words, the target torque T of the steering motor 16 is determined. target The absolute value is less than the threshold torque T threshold The absolute value of the steering angle θ is less than the absolute value of the constraint angle θ. limit The absolute value of.

[0098] Therefore, in the determination result of step S30, when it is determined that additional steering feel operation is required due to the failure of the above conditions, the rotation direction requiring steering feel operation is determined by determining whether the differential value of the absolute value of the steering angle is greater than 0 and whether the differential value of the steering angle is greater than 0 (S40).

[0099] In the determination result of step S40, when it is necessary to limit the rotation of disk 10 in its counterclockwise direction, such as Figure 3 As shown, the cam 20 rotates eccentrically in the second eccentric direction, causing the first brake arm 30a to make frictional contact with the outer peripheral surface of the disc 10, thereby providing additional steering feel for the counterclockwise rotation of the disc 10 and thus limiting the counterclockwise rotation of the steering wheel 12 (S50).

[0100] Meanwhile, in the determination result of step S40, when it is necessary to limit the rotation of disk 10 in its clockwise direction, such as Figure 4 As shown, the cam 20 rotates eccentrically in the third eccentric direction, causing the second brake arm 30b to make frictional contact with the outer peripheral surface of the disc 10, thereby providing additional steering feel for the clockwise rotation of the disc 10 and thus limiting the clockwise rotation of the steering wheel 12 (S60).

[0101] Because the steering motor 14 maintains maximum torque during the process of limiting the rotation of the disc 10 in steps S50 and S60, the driver is more certain that the steering angle cannot be rotated in the corresponding direction of rotation (S70).

[0102] Subsequently, the target torque T of the steering motor 16 was determined. target Is the absolute value less than the threshold torque T? threshold The absolute value of the steering angle θ and whether the absolute value of the steering angle θ is less than the constraint angle θ. limit The absolute value (S80).

[0103] In the determination result of step S80, when the above conditions are met, such as Figure 2 As shown, bidirectional rotation of the steering wheel is allowed by eccentrically rotating the cam 20 in the first eccentric direction, so that both the first brake arm 30a and the second brake arm 30b release their frictional contact with the outer peripheral surface of the disc 10 (S90).

[0104] Meanwhile, if a fault is detected in the steering motor 14 or actuator 21 during vehicle start-up (S110), its power is interrupted, and the brake arm 30 returns to the starting position (initial position) to provide the driver with a predetermined level (e.g., 5 Nm) of friction (S120).

[0105] Therefore, since friction is provided even when the steering feel function is lost due to a malfunction of the steering feel motor 14, steering sensitivity is reduced and safe driving is possible.

[0106] For reference, the function of identifying the steering angle and sending the rack target position can be converted into a dual function (fully redundant angle sensor / auxiliary controller 52) on the controller 50 (ECU), which is a basic function that requires fault operation.

[0107] Furthermore, the main functions of the steering sensing device (such as the control of the steering sensing motor and actuator) can be performed by the main controller 51 in the controller 50.

[0108] As described above, due to the selective frictional contact between the disc 10 constrained by the steering shaft 11 and the cam 20, controlled by the actuator 21 according to the change in the rotation angle of the cam 20, additional steering feel is provided only in the rotational direction to be restricted.

[0109] Therefore, when the driver wants to feel a high load (e.g., the feeling of the end of the steering angle), the torque missing in the steering feel motor can be additionally provided, and when the driver performs a reverse operation of the steering wheel 12 while the unidirectional rotation of the wheel 10 is restricted, the steering wheel 12 can rotate, thereby eliminating the reverse locking phenomenon of the steering wheel 12.

[0110] Furthermore, when the steering motor malfunctions while the vehicle is in motion, it reduces steering sensitivity by immediately providing friction to the driver and preventing sudden steering, thereby providing the driver with handling and driving safety.

[0111] In addition, when the engine is running, it can prevent the steering wheel from rotating excessively in both directions without any additional configuration or voltage application.

[0112] Furthermore, the term "controller" refers to a hardware device including 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 controller according to an exemplary embodiment of the invention may 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, and a processor configured to perform the aforementioned operations using the data stored in the memory. The memory and processor may be separate chips. Alternatively, the memory and processor may be integrated into a single chip. The processor may be implemented as one or more processors.

[0113] The controller may be at least one microprocessor operated by a predetermined program, which may include a series of commands for performing methods according to various exemplary embodiments of the present invention.

[0114] The foregoing invention can also be embodied as computer-readable code on a computer-readable recording medium. This computer-readable recording medium is any data storage device capable of storing 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 such as carrier waves (e.g., transmission over the Internet).

[0115] For ease of interpretation and accurate definition of the appended claims, the terms “upper,” “lower,” “inner,” “outer,” “on,” “under,” “upward,” “downward,” “front,” “back,” “rear,” “inner,” “external,” “inward,” “outer,” “internal,” “external,” “forward,” and “backward” are used to describe features of exemplary embodiments with reference to the positions of features shown in the accompanying drawings. It will be further understood that the term “connection” or its derivatives refer to both direct and indirect connections.

[0116] For purposes of illustration and description, the foregoing description of specific exemplary embodiments of the invention has been given. These are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it will be apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and its practical application, enabling others skilled in the art to make and utilize various exemplary embodiments of the invention and their various alternatives and modifications. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A steering feel assist apparatus of a steer-by-wire system, the steering feel assist apparatus comprising: a disc connected to a steering shaft and configured to rotate together with the steering shaft; a cam engaged to an actuator and configured to receive a rotational force of the actuator to eccentrically rotate; and a brake arm configured to selectively come into frictional contact with an outer circumferential surface of the disc to provide a predetermined frictional force in a positive rotational direction of the disc when the brake arm rotates together with the rotation of the cam; a steering angle sensor configured to detect a steering angle of the steering shaft; a steering feel motor configured to provide a steering feel to the steering shaft; a steering motor coupled to a rack and configured to provide a steering force to the rack; and a controller electrically connected to the steering angle sensor, the steering feel motor, the steering motor, and the actuator, and configured to selectively provide a steering feel in the positive rotational direction of the steering shaft by controlling an operation of the steering feel motor or the actuator according to the steering angle and a torque value of the steering motor, wherein the controller is configured to limit the rotation of the steering shaft by generating a maximum repulsive force in the steering feel motor when an absolute value of a target torque of the steering motor is equal to or greater than an absolute value of a threshold torque and a differential value of the absolute value of the target torque is greater than 0, to maintain the absolute value of the target torque above the absolute value of the threshold torque and determine that an additional steering feel operation is required when an absolute value of the steering angle is maintained above an absolute value of a constraint angle corresponding to an end point of the steering angle after the steering feel motor generates the maximum repulsive force, to determine a rotational direction in which a steering feel operation is required by determining whether a differential value of the absolute value of the steering angle is greater than 0 and whether a differential value of the steering angle is greater than 0, and to provide the predetermined frictional force in the rotational direction. A rotational shaft is provided at a first end portion of the brake arm, and the cam is in contact with a middle portion of the brake arm, such that when the cam eccentrically rotates and selectively comes into frictional contact with the outer circumferential surface of the disc, a second end portion of the brake arm rotates about the rotational shaft in a direction in which the second end portion of the brake arm approaches or is distanced from the disc.

2. The turning sense aid apparatus according to claim 1, wherein 3.The steering feel assist apparatus of claim 2, further comprising: a pressure spring installed on a housing and configured to provide an elastic force to the brake arm in a rotational direction of the disc in which the second end portion of the brake arm faces. 4.The steering feel assist apparatus of claim 2, wherein the brake arm includes a first brake arm and a second brake arm provided at a first side and a second side of the cam, respectively, wherein wherein a first rotational shaft formed on a first end portion of the first brake arm and a second rotational shaft formed on a first end portion of the second brake arm are located in a direction opposite to the disc with respect to the cam, and wherein a second end portion of the first brake arm and a second end portion of the second brake arm are located at a first side of the disc and a second side of the disc, respectively. ​ 5. The turning sense aid of claim 4, wherein One or both of the second ends of the first and second brake arms are in frictional contact with a point of a radius of rotation of the cam, and one or both of the second ends of the first and second brake arms are in contact with an outer circumferential surface of the disc while drawing a tangent.

6. The steering feel assist apparatus according to claim 4, wherein, the disc is coupled to the steering shaft by a shaft, wherein the cam is mounted on one side of the disc, and wherein axial lines of rotation axes of the disc, the cam, and the first and second brake arms are parallel to each other in the same direction.

7. The steering feel assist apparatus according to claim 4, wherein, the first and second brake arms are selectively in frictional contact with the disc in an eccentric direction of the cam; wherein the second ends of the first and second brake arms release the frictional contact with the disc in a first eccentric direction in which the cam is eccentric toward the first and second rotation axes over an entire rotation portion of the cam; wherein the second end of the first brake arm is in frictional contact with the disc in a second eccentric direction in which the cam is eccentric toward the second brake arm; wherein the second end of the second brake arm is in frictional contact with the disc in a third eccentric direction in which the cam is eccentric toward the first brake arm; and wherein the second ends of the first and second brake arms are in frictional contact with the disc in a fourth eccentric direction in which the cam is eccentric toward the disc.

8. The steering feel assist apparatus according to claim 2, further comprising: a return spring mounted on the housing and engaged with the cam, and the return spring is configured to provide an elastic force to the cam in a direction in which the cam is eccentric toward the disc.

9. The steering feel assist apparatus according to claim 2, wherein, a friction brush is individually coupled to the second end of the brake arm to be in frictional contact with the outer circumferential surface of the disc, and wherein a friction pattern is formed on the outer circumferential surface of the disc.

10. The turning sense aid apparatus according to claim 1, wherein the controller: provides a frictional force to a forward rotation or a reverse rotation of the disc by the brake arm by controlling the rotation of the cam by the actuator.

11. The steering feel assist apparatus according to claim 10, wherein the brake arm includes a first brake arm and a second brake arm disposed on a first side and a second side of the cam, respectively, wherein when the target restraint direction of the disc is a reverse direction, the first brake arm is brought into frictional contact with the disc by controlling the rotation of the cam, and the second brake arm releases the frictional contact with the disc so as to be in frictional contact with the disc for a reverse rotation of the disc; and wherein when the target restraint direction of the disc is a forward direction, the second brake arm is brought into frictional contact with the disc by controlling the rotation of the cam, and the first brake arm releases the frictional contact with the disc so as to be in frictional contact with the disc for a forward rotation of the disc.

12. The steering feel assist apparatus according to claim 11, the first and second brake arms are selectively in frictional contact with the disc in an eccentric direction of the cam; wherein the second ends of the first and second brake arms release the frictional contact with the disc in a first eccentric direction in which the cam is eccentric toward the first and second rotation axes over an entire rotation portion of the cam; wherein the second end of the first brake arm is in frictional contact with the disc in a second eccentric direction in which the cam is eccentric toward the second brake arm; wherein the second end of the second brake arm is in frictional contact with the disc in a third eccentric direction in which the cam is eccentric toward the first brake arm; and wherein the second ends of the first and second brake arms are in frictional contact with the disc in a fourth eccentric direction in which the cam is eccentric toward the disc.

13. The steering feel assist apparatus according to claim 12, a return spring mounted on the housing and engaged with the cam, and the return spring is configured to provide an elastic force to the cam in a direction in which the cam is eccentric toward the disc.

14. The steering feel assist apparatus according to claim 12, a friction brush is individually coupled to the second end of the brake arm to be in frictional contact with the outer circumferential surface of the disc, and wherein a friction pattern is formed on the outer circumferential surface of the disc.

15. The steering feel assist apparatus according to claim 14, the controller: provides a frictional force to a forward rotation or a reverse rotation of the disc by the brake arm by controlling the rotation of the cam by the actuator.

12. The turning sense aid of claim 10, wherein, the controller is configured to perform control to maintain the maximum repulsive force of the steering feel motor during a process in which the brake arms provide the frictional force to the disc.

13. The steering feel assisting apparatus according to claim 1, wherein the brake arms include a first brake arm and a second brake arm disposed on a first side and a second side of the cam, respectively, and wherein the controller is configured to control the first brake arm and the second brake arm to release the frictional contact with the disc when an absolute value of the target torque is smaller than an absolute value of the threshold torque and an absolute value of the steering angle is smaller than an absolute value of a constraint angle corresponding to an end of the steering angle after the steering feel motor generates the maximum repulsive force.

14. The steering feel assisting apparatus according to claim 12, wherein the brake arms include a first brake arm and a second brake arm disposed on a first side and a second side of the cam, respectively, and wherein the controller is configured to control the first brake arm and the second brake arm to release the frictional contact with the disc when an absolute value of the target torque is smaller than an absolute value of the threshold torque and an absolute value of the steering angle is smaller than an absolute value of the constraint angle after the steering feel motor generates the maximum repulsive force.

15. The steering feel assisting apparatus according to claim 1, wherein the brake arms include a first brake arm and a second brake arm disposed on a first side and a second side of the cam, respectively, and wherein the controller is configured to perform control to bring the first brake arm and the second brake arm into frictional contact with the disc by controlling rotation of the cam during startup of the vehicle, thereby providing a frictional force in a forward rotation direction and a reverse rotation direction of the disc.

16. A method of controlling a steering sense assist device, the steering sense assist device comprising: a disc connected to a steering shaft and configured to rotate together with the steering shaft; a cam engaged to an actuator and configured to receive a rotational force of the actuator to rotate eccentrically; a first brake arm and a second brake arm configured to selectively come into frictional contact with an outer circumferential surface of the disc to provide a predetermined frictional force in a forward rotation direction of the disc when the first brake arm and the second brake arm rotate together with rotation of the cam; a steering feel motor configured to provide a steering feel to the steering shaft; and a steering motor coupled to a rack and configured to provide a steering force to the rack, the method comprising: selectively providing a steering feel in the forward rotation direction of the steering shaft by controlling operation of the steering feel motor or the actuator according to a steering angle and a torque value of the steering motor by a controller electrically connected to the steering feel motor, the actuator, and the steering motor, restricting rotation of the steering shaft by generating a maximum repulsive force in the steering feel motor by the controller when an absolute value of a target torque of the steering motor is equal to or greater than an absolute value of a threshold torque and a differential value of the absolute value of the target torque is greater than 0, and determining, by the controller, that an additional steering feel operation is required after the steering feel motor generates the maximum repulsive force while maintaining the absolute value of the target torque above the absolute value of the threshold torque and while maintaining the absolute value of the steering angle above the absolute value of the constraint angle corresponding to the end point of the steering angle; determining the rotational direction in which the steering feel operation is required by determining whether the differential value of the absolute value of the steering angle is greater than 0 and whether the differential value of the steering angle is greater than 0; and providing a predetermined frictional force in the rotational direction; and controlling, by the controller, the first brake arm and the second brake arm to release the frictional contact with the disc after the steering feel motor generates the maximum repulsive force while the absolute value of the target torque is less than the absolute value of the threshold torque and the absolute value of the steering angle is less than the absolute value of the constraint angle.

17. The method of claim 16, controlling, by the controller, the rotation of the cam to provide a frictional force to the positive rotation or the reverse rotation of the disc by the first brake arm and the second brake arm when the rotation of the cam is controlled by the control of the actuator.

18. The method of claim 17, wherein controlling, by the controller, the rotation of the cam to bring the first brake arm into frictional contact with the disc and to release the second brake arm from the frictional contact with the disc when the target constraint direction of the disc is the reverse direction, so as to be in frictional contact with the disc for the reverse rotation of the disc; and wherein, when the target constraint direction of the disc is the positive direction, the rotation of the cam is controlled by the controller to bring the second brake arm into frictional contact with the disc and to release the first brake arm from the frictional contact with the disc, so as to be in frictional contact with the disc for the positive rotation of the disc.

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