STEERING DEVICE, STEERING METHOD AND STEERING SYSTEM

Abstract

Steering control device (200) comprising: a steering angle determination unit (220) that determines a current steering angle of a steering wheel (111) as a reference steering angle; a control unit (230) which controls a drive shaft to steer a road wheel (131) to the left or right within a first angular range (320) with respect to the reference steering angle; and a slip determination unit (210) which determines whether a vehicle is slipping, characterized by that in a steer-by-wire system in which a steering column device comprising the steering wheel and a steering column and a rack device comprising the road wheel (131) and a rack are not physically connected, when it is determined that the vehicle is slipping, the steering angle determination unit (220) determines the current steering angle of the steering wheel (111) as the reference steering angle and the control unit (230) controls the drive shaft to steer the road wheel (131) to the left or right within the first angle range (320), wherein the first angle range (320) is determined based on at least one of physical information about the vehicle, speed information about the vehicle, and gradient information about a road on which the vehicle is traveling.

Description

field of technology

[0001] The disclosure relates to a steering control apparatus and method, as well as a steering system for increasing traction by steering the road wheels to the left or right along the current steering direction when the vehicle is skidding. Technical background

[0002] When the vehicle is driving on a road surface with reduced friction, such as rain, snow, or sand, the vehicle may skid, making it difficult to drive the vehicle as intended by the driver or the autonomous driving system. If such skidding occurs, the driver may lose control of the vehicle, even on a slight incline or small protrusion.

[0003] In particular, 2WD (two-wheel drive) vehicles, which drive either only the front or only the rear axle, are vulnerable on low-friction roads, such as in rain or snow. Only some vehicles capable of switching to all-wheel drive (4WD) can avoid such slippage, and accordingly, there is a need for a method for increasing traction that can be generally used for various vehicle types, such as FF, FR, and all-wheel drive. Document DE 10 2015 224 760 A1 relates to a method for actively assisting the steering when a vehicle is stuck and shows a steering control device of this type. A vehicle control system for negotiating obstacles is the subject of document DE 10 2005 019 339 A1. Document GB 2 344 326 A proposes that, on soft terrain, a steering angle and optionally also a drive torque oscillate around a steering angle desired by a driver to improve traction. Detailed description of the inventionTechnical task

[0004] Against this background, the disclosure proposes a system for increasing traction that can be generally used for various vehicle types, such as FF, FR and 4WD. Technical solution

[0005] In one aspect of the disclosure, conceived in light of the above objects, a steering control device is provided, including a slip determination unit that determines whether a vehicle is skidding, a steering angle determination unit that determines a current steering angle of a steering wheel as a reference steering angle when it is determined that the vehicle is skidding, and a controller that controls a drive shaft to allow a road wheel to steer left or right within a first angular range with respect to the reference steering angle. This aspect is defined in claim 1. Individual embodiments of this aspect are apparent from the claims dependent on claim 1.

[0006] In another aspect of the disclosure, a steering control method is provided, including a slip determination step that determines whether a vehicle is skidding, a steering angle determination step that determines a current steering angle of a steering wheel as a reference steering angle when the vehicle is determined to be skidding, and a control step that controls a drive shaft to allow a road wheel to steer left or right within a first angular range with respect to the reference steering angle. This other aspect is defined in claim 8. Specific embodiments of this other aspect are apparent from the claims dependent on claim 8.

[0007] In another aspect of the disclosure, a steering system is provided that includes an input device that detects a steering angle of a steering wheel of a vehicle, an output device that drives a road wheel of the vehicle, and a control unit that determines whether the vehicle is skidding and, if it is determined that the vehicle is skidding, sets a current steering angle of the steering wheel as a reference steering angle and controls a drive shaft to allow the road wheel to steer left or right within a first angular range with respect to the reference steering angle. This further aspect is defined in claim 13. Beneficial effects

[0008] As described above, according to the disclosure, when the vehicle skids, the drive shaft is controlled to steer the road wheels to the left or right with respect to the current steering angle of the steering wheel, thereby increasing traction on the low-friction road surface such as a rainy or snowy road, thus enabling stable driving. Brief description of the drawings Fig. 1 is a view showing a configuration of a vehicle according to an embodiment of the disclosure. Fig. 2 is a view showing a configuration of a steering control device according to an embodiment of the disclosure. Fig. 3 is a view illustrating an embodiment in which a steering control device of the disclosure steers road wheels to the left or right. Fig. 4 is a view showing an embodiment of stopping feedback to a steering wheel when a steering control device of the disclosure steers road wheels to the left or right. Fig. 5 is a view illustrating an embodiment in which a steering control device of the disclosure steers the front road wheels and the rear road wheels to the left or right using different setting values. Fig. 6 is a view showing another embodiment in which a steering control device of the disclosure steers the front road wheels and the rear road wheels to the left or right using different setting values. Fig. 7 is a view illustrating an embodiment in which a steering control device of the disclosure enables the road wheels to follow the steering of a steering wheel when the turning angle of the steering wheel is changed. Fig. 8 is a flowchart showing a steering control method according to an embodiment of the disclosure. Fig. 9 is a flowchart illustrating one embodiment of determining slip of a vehicle in a steering control method of the disclosure. Fig. 10 is a flowchart illustrating one embodiment of controlling a drive shaft in a steering control method of the disclosure. Fig. 11 is a flowchart showing another embodiment of control of a drive shaft in a steering control method of the disclosure. Fig. 12 is a flowchart showing another embodiment of control of a drive shaft in a steering control method of the disclosure. Fig. 13 is a view showing a configuration of a steering system according to an embodiment of the disclosure. Best way to implement the invention

[0009] Embodiments of the disclosure will now be described in detail with reference to the accompanying drawings. Terms such as "first," "second," "A," "B," "(A)," or "(B)" may be used herein to describe elements of the disclosure. These terms are not used to define the nature, order, sequence, or number of the elements, etc., but are used merely to distinguish the respective element from other elements. When a first element is referred to as "connected or coupled," "touching or overlapping," etc., a second element is referred to as "connecting or coupling," "touching or overlapping," etc., this is to be understood as meaning that not only can the first element be ‘directly connected or coupled’ to the second element, or ‘directly touch or overlap’ it, but also that a third element can be ‘interposed’ between the first and second elements, or that the first and second elements can be ‘connected or coupled’ to each other via a fourth element, or ‘touch or overlap’ it, etc.

[0010] In the disclosure, "vehicle" may be a term that includes automobiles and motorcycles. Furthermore, a vehicle may be a concept that includes all internal combustion engine vehicles with an engine as a power source, hybrid vehicles with an engine and an electric motor as power sources, and electric vehicles with an electric motor as a power source. The following description primarily refers to a car. In the following description, "forward" means a forward direction of travel of the vehicle, and "reverse" means a reverse direction of travel of the vehicle.

[0011] Fig. 1 is a view showing a configuration of a vehicle according to an embodiment of the disclosure. The vehicle of the disclosure may be equipped with a steer-by-wire (SBW) system. An example in which the steering control device of the disclosure is applied to an SBW system will be described below. However, vehicles to which the steering control device of the disclosure is applied are not limited to vehicles with an SBW system, but may also be applied to vehicles in which a steering column device and a rack device are mechanically connected.

[0012] Steer-by-wire (SBW) system refers to a device that detects the driver's operation of the steering wheel and generates a signal, or receives a signal from an autonomous driving device or system and controls the steering of the road wheels using the signal, instead of a mechanical structure connecting the steering wheel and the road wheels.

[0013] In electric power steering, the steering wheel, steering column, intermediate shaft (IMS) for the steering mechanism, rack, and road wheel are mechanically connected, so that the road wheels or rack and steering wheel always remain neutral. In other words, the road wheel or rack and steering wheel are physically connected and always synchronized.

[0014] In contrast, in the SBW system, an input side (steering column device) including the steering wheel and the steering column and an output side (rack device) including the road wheel and the rack are not physically connected and are controlled based on signals generated by the electronic control unit.

[0015] Referring to Fig. 1, a vehicle of the disclosure includes a steering column device 110 that receives a steering control signal for the vehicle from a driver of the vehicle, an autonomous driving device, or an autonomous driving system, a steering control device 120 that generates a steering control signal for a rack and pinion device 130 using information input from the steering column device 110, and the rack and pinion device 130 that controls a road wheel 131 of the vehicle according to the steering control signal.

[0016] Specifically, the steering column device 110 may include the steering wheel 111, a steering shaft, a steering angle sensor that detects the steering angle of the steering wheel, a torque sensor that detects the torque of the steering shaft of the steering wheel, and a reaction force motor that provides a reaction force torque corresponding to the rotation of the steering wheel. The rack device 130 may include the road wheel 131, a drive shaft 132, a steering output sensor capable of detecting the rotation angle of the road wheel, a steering motor that generates an assist force to enable the rotation of the road wheel, a steering motor position sensor that detects the position of the steering motor rotation shaft, and a rack position sensor that detects the position of the rack.The steering control device may also be a domain control unit (DCU) that controls a number of driver assistance systems or autonomous driving devices or systems, as well as the electronic control unit (ECU) or steering controller.

[0017] When the driver turns the steering wheel, the torque of the torsion bar and the rotation of the steering wheel detected by the autonomous driving device or the autonomous driving system or by the steering angle sensor and the torque sensor are transmitted to the steering control device, and the steering control device generates a current for steering control of the road wheel and outputs it to the steering motor, thereby steered the road wheel.

[0018] Fig. 2 is a view showing a configuration of a steering control device 200 according to an embodiment of the disclosure.

[0019] Referring to Fig. 2, the steering control device 200 of the disclosure may include a slip determination unit 210 that determines whether the vehicle is skidding, a steering angle determination unit 220 that determines the current steering angle of the steering wheel as a reference steering angle when it is determined that the vehicle is skidding, and a control unit 230 that controls the drive shaft to steer the road wheel left or right within a first angular range with respect to the reference steering angle.

[0020] The slip determination unit 210 of the disclosure may determine whether the vehicle is skidding. In one embodiment, the slip determination unit 210 may determine whether the vehicle is skidding by using information about whether the vehicle's drive shaft is slipping, information about the vehicle's speed, and / or information about the gradient of the road on which the vehicle is traveling.The slip determination unit 210 may determine whether the vehicle is skidding based on whether the drive shaft of the vehicle is slipping and / or based on the vehicle speed information and / or the slope information of the road on which the vehicle is traveling, or the slip determination unit 210 may determine a plurality of pieces of information about whether the vehicle is skidding based on whether the drive shaft of the vehicle is slipping, the vehicle speed information and / or the slope information of the road on which the vehicle is traveling in a predetermined order to thereby determine whether the vehicle is skidding.

[0021] In one embodiment, the slip determination unit 210 may determine whether the drive shaft of the vehicle is slipping, and if it is determined that the drive shaft is slipping, detect the slope of the road surface, determine whether the slope of the road surface is greater than a first slope threshold, if it is determined that the first slope of the road surface is the first slope threshold, determine whether the vehicle speed is less than a first threshold vehicle speed, and if it is determined that the vehicle speed is less than the first threshold vehicle speed, determine that the vehicle is skidding.

[0022] The inclination of the road surface can be detected, for example, using a vehicle-mounted inclination sensor. Or the vehicle receives map information, e.g., through navigation, and extracts information about the road on which the vehicle is located from the map information using the vehicle position information. In one embodiment, the vehicle speed can be detected using a vehicle-mounted speed sensor. In another embodiment, the vehicle speed can be received from another ECU or from an external device or infrastructure outside the vehicle via a communication unit, e.g., a V2X communication unit. The V2X communication unit performs wireless communication with a server or another vehicle or infrastructure device.In the present embodiment, the V2X communication entity means that the vehicle exchanges information with an entity such as another vehicle, a mobile device, or a road via a wired / wireless network or equivalent technology. The V2X communication entity may include the concepts of vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-nomadic device (V2N), and vehicle-to-pedestrian (V2P) communication. The V2X communication entity may be based on Dedicated Short Range Communication (DSRC) and use Wireless Access in Vehicular Environments (WAVE) of the American Institute of Electrical and Electronic Engineers (IEEE) or IEEE 802.11p communication technology using a 5.9 GHz band, but is not limited to these, but should be understood to include all inter-vehicle communications currently developed or to be developed in the future.

[0023] In one example, the slip determination unit 210 may determine whether slippage occurs on the drive shaft of the vehicle based on the vehicle speed information, the road wheel rotational speed information detected from the road wheel brake shaft, and the vehicle inertia sensor information.

[0024] In one example, the first slope threshold may be 10 degrees. If the slope of the road traveled by the vehicle is greater than 10 degrees, the slip determination unit 210 may determine that slippage is occurring in the vehicle's drive shaft. Information about the first slope threshold may have been previously stored in the vehicle.

[0025] In one example, the first threshold vehicle speed may be 20 km / h, and if the vehicle's traveling speed is less than 20 km / h, the slip determination unit 210 may determine that slippage is occurring on the vehicle's drive shaft. Information about the first threshold vehicle speed may have been previously stored in the vehicle.

[0026] The steering angle determination unit 220 of the disclosure may determine the current steering angle of the steering wheel as a reference steering angle when it is determined that the vehicle is skidding. The control unit 230 may control the drive shaft so that the road wheel can steer left or right within a first angular range with respect to the reference steering angle.

[0027] Fig. 3 is a view illustrating an embodiment in which a steering control device of the disclosure steers road wheels to the left or right. Referring to Fig. 3, when it is determined that the vehicle is skidding, the steering angle determination unit 220 can obtain information about the current steering angle from the steering wheel or the steering control unit controlling the steering wheel and determine the current steering angle of the steering wheel or the steering control unit as the reference steering angle. The control unit 230 can then control the drive shaft so that the road wheel can steer left or right with respect to the reference steering angle.

[0028] In other words, the control unit 230 can determine the current steering angle of the steering wheel as the direction of travel and steer the road wheel left or right with respect to the direction of travel corresponding to the current steering angle, i.e., a reference steering axis 310. The reference steering axis 310 corresponds to the reference steering angle determined by the steering angle determination unit. The control unit 230 can control the drive shaft such that the road wheel can steer left or right within a first angular range 320 with respect to the reference steering axis 310.

[0029] In one embodiment, the first angular range 320 may be determined based on physical information about the vehicle and / or information about the vehicle speed and / or information about the gradient of the road on which the vehicle is traveling. Here, the physical information of the vehicle may include information such as the length, width, and drive type (e.g., FF, FR, or 4WD) of the vehicle. Or, the first angular range 320 may be determined by a rated value. In one example, the first angular range may be five degrees.

[0030] In one embodiment, the control unit 230 can control the drive shaft so that the road wheel can steer left or right within a first angular range at a first frequency relative to the reference steering angle. The first frequency indicates the speed at which the control unit steers the road wheel left or right. The first frequency can be set to a pre-stored value or determined according to a pre-stored frequency pattern.

[0031] The pre-stored frequency pattern may include at least one of physical information about the vehicle, information about the vehicle speed, and information about the gradient of the road on which the vehicle is traveling. The control unit 230 may determine the frequency value corresponding to the at least one of physical information, vehicle speed information, and information about the gradient of the road on which the vehicle is traveling in the pre-stored frequency pattern as the first frequency and steer the road wheel at the corresponding frequency.

[0032] When the control unit 230 controls the drive shaft so that the road wheel can steer left or right within the first angle range 320 with respect to the reference steering angle, the control unit 230 may control so that the steering state information about the road wheel is not returned to the steering wheel.

[0033] In the SBW system, since an input side (steering column device), including the steering wheel and the steering column, and an output side (rack device), including the road wheel and the rack, are not physically connected and are controlled based on signals generated by the electronic control unit, the control unit 230 can transmit different control signals to the input and output sides. Accordingly, the control unit 230 can control the drive shaft for steering the road wheel while simultaneously controlling that the road wheel steering control information is not returned to the steering wheel.

[0034] Fig. 4 is a view showing an embodiment of stopping feedback to a steering wheel 111 when a steering control device 120 of the disclosure steers road wheels 131 to the left or right.

[0035] Referring to Fig. 4, the steering control device 120 controls the drive shaft 132 to allow the road wheel 131 to steer left or right within a first angular range 420 with respect to a reference steering angle 410 determined by the steering angle determination unit 220. In this case, the steering control device 120 does not send a control signal to impart a steering force to the steering wheel 111 when steering the road wheel 131. Since no steering force is applied to the steering wheel 111, no change in the steering wheel 111 occurs.

[0036] Since the steering wheel is not moved even when the steering control device 120 of the disclosure steers the road wheel to the left or right to increase traction, it is possible to increase driving stability without causing discomfort to the driver or passenger.

[0037] In one embodiment, the road wheels include front road wheels and rear road wheels. The control unit 230 can control the drive shaft so that the front road wheels can steer left or right within a second angular range with respect to the reference steering angle 410, and the rear road wheels can steer left or right within a third angular range with respect to the reference steering angle 410. In other words, the control unit 230 can control the front road wheels and the rear road wheels with different setting values.

[0038] Fig. 5 is a view illustrating an embodiment in which a steering control device 200 of the disclosure steers the front road wheels and the rear road wheels to the left or right using different setting values. As shown in Fig. 5, the control unit 230 can control the drive shaft so that the front road wheel can steer left or right within a second angular range 510 with respect to the reference steering angle. At the same time, the control unit 230 can control the drive shaft so that the rear road wheel can steer left or right within a third angular range 520 with respect to the reference steering angle. The second angular range 510 can be set smaller than the third angular range 520. For example, the ratio between the second angular range 510 and the third angular range 520 can be preset, and the control unit 230 can determine the second angular range 510 and the third angular range 520 according to the preset ratio.

[0039] Fig. Figure 6 is a view illustrating another embodiment in which a steering control device 200 of the disclosure steers the front road wheels and the rear road wheels to the left or right with different setting values. Likewise, the control unit 230 can steer the front road wheel and the rear road wheel, respectively, within a second angular range 610 and a third angular range 620 with respect to the reference steering angle. Fig. 6, the third angle range 620 can be set smaller than the second angle range 610.

[0040] Thus, the steering control device 200 can steer the front road wheel and the rear road wheel of the vehicle in different areas, thus efficiently increasing traction.

[0041] In one embodiment, the steering angle determination unit 220 determines whether the steering angle of the steering wheel is identical to the reference steering angle. If it is determined that the steering angle of the steering wheel does not match the reference steering angle, the control unit 230 may stop controlling the drive shaft to allow the road wheel to steer left or right within the first angle range and control the drive shaft to follow the steering angle of the steering wheel.

[0042] The steering angle determination unit 220 may obtain the steering angle information of the steering wheel from a steering angle sensor in real time or at regular intervals. The steering angle determination unit 220 may determine that the vehicle is skidding and determine that the steering angle information of the steering wheel when the vehicle is skidding is the reference steering angle. Then, it may obtain the steering angle information of the steering wheel from the steering angle sensor and determine whether the obtained steering angle information of the steering wheel is identical to the reference steering angle. Determining that the steering angle of the steering wheel is not identical to the reference steering angle indicates that the driver has tampered with the steering wheel or that the autonomous driving device or system has controlled the steering. Thus, it may be determined that the driver or the autonomous driving device or system intends to steer.Thus, if it is determined that the steering angle of the steering wheel does not match the reference steering angle, the control unit 230 can no longer control the drive shaft in such a way that the road wheel can steer to the left or right within the first angle range, but rather in such a way that the drive shaft follows the steering angle of the steering wheel.

[0043] When the steering angle determination unit 220 determines that the steering angle of the steering wheel varies by a predetermined range or more, the control unit 230 may stop controlling the drive shaft to allow the road wheel to steer left or right within the first angle range and control the drive shaft to follow the steering angle of the steering wheel.

[0044] Fig. 7 is a view illustrating an embodiment in which a steering control device 120 of the disclosure allows the road wheels to follow the steering of a steering wheel when the turning angle of the steering wheel is changed.

[0045] Referring to Fig. 7, when the steering angle determination unit 220 determines that the steering wheel 111 is rotated by a predetermined range 730 or more, that is, when it determines that the steering angle of the steering wheel 111 varies by a predetermined threshold angle or more, the steering angle determination unit 220 may determine that the steering angle of the steering wheel 111 is not identical to a reference steering angle 710. If it is determined that the steering angle of the steering wheel 111 does not match the reference steering angle, the control unit stops controlling the drive shaft 132 to allow the road wheel 131 to steer left or right within the first angular range with respect to the reference steering angle. Further, the control unit 230 may output a steering control signal for the road wheel 131 to allow the road wheel 131 to conform to a range 720 corresponding to the steering angle of the steering wheel 111.

[0046] When the vehicle skids, the drive shaft is controlled by the steering control device 120 so that the road wheels are steered left or right with respect to the current steering angle of the steering wheel, thereby increasing traction on the low-friction road surface, such as a rainy or snowy road, and thus enabling stable driving.

[0047] Fig. 8 is a flowchart showing a steering control method according to an embodiment of the disclosure.

[0048] With reference to Fig. 8, a steering control method of the disclosure may include a slip determination step S810 that determines whether the vehicle is skidding, a steering angle determination step S820 that determines the current steering angle of the steering wheel as a reference steering angle when it is determined that the vehicle is skidding, and a control step S830 that controls the drive shaft to steer the road wheel left or right within a first angular range with respect to the reference steering angle.

[0049] First, the steering control device 200 applying the steering control method of the disclosure can determine whether the vehicle is skidding. Fig. 9 is a flowchart illustrating one embodiment of determining slip of a vehicle in a steering control method of the disclosure.

[0050] In the slip determination step S810 of one embodiment, the steering control device 200 may determine whether the vehicle is skidding by using information about whether the vehicle's drive shaft is slipping, information about the vehicle's speed, and / or information about the slope of the road on which the vehicle is traveling. The steering control device 200 may determine whether the vehicle is skidding by obtaining, in a predetermined order, a plurality of pieces of information about whether the vehicle's drive shaft is slipping, the vehicle speed information, and the slope information about the road on which the vehicle is traveling. The steering control device 200 may also determine whether the vehicle is skidding based on whether the vehicle's drive shaft is slipping, information about the vehicle's speed, and information about the slope of the road on which the vehicle is traveling.

[0051] In one embodiment, the steering control device 200 may determine whether the drive shaft of the vehicle is slipping, and if it is determined that the drive shaft is slipping, detect the inclination of the vehicle's road surface, determine whether the inclination of the vehicle's road surface is greater than a first inclination threshold, if it is determined that the first inclination of the vehicle's road surface is the first inclination threshold, determine whether the vehicle speed is less than a first vehicle speed threshold, and if it is determined that the vehicle speed is less than the first vehicle speed threshold, determine that the vehicle is skidding.

[0052] The inclination of the road surface can be detected, for example, using a vehicle-mounted inclination sensor. Or the vehicle receives map information, for example, through navigation, and extracts information about the road on which the vehicle is located from the map information using the vehicle position information. In one embodiment, the vehicle speed can be detected using a speed sensor mounted on the vehicle. In another embodiment, the vehicle speed can be received via another control unit or from an external device or infrastructure outside the vehicle via a communication unit, for example, a V2X communication unit. The V2X communication unit is a component that enables wireless communication, for example,with a server or other vehicle or infrastructure device, and their specific functions or implementation scheme may relate to what is described in connection with the steering control device of . Fig. 2 was described.

[0053] In one example, the steering control device 200 may determine whether slippage occurs on the vehicle's drive shaft based on the vehicle speed information, the road wheel rotational speed information detected by the road wheel brake shaft, and the vehicle inertia sensor information.

[0054] In one example, the first slope threshold may be 10 degrees, and if the slope of the road being traveled by the vehicle is greater than 10 degrees, the steering control device may determine that slippage is occurring on the vehicle's drive shaft.

[0055] In one example, the first vehicle speed threshold may be 20 km / h, and when the vehicle's ground speed is below 20 km / h, the steering controller may determine that slippage is occurring on the vehicle's drive shaft.

[0056] The steering control device 200 of the disclosure may determine the current steering angle of the steering wheel as the reference steering angle when it is determined that the vehicle is skidding (S820). The steering control device may control the drive shaft so that the road wheel can steer left or right within a first angular range with respect to the reference steering angle (S830).

[0057] In one embodiment, the first angular range may be determined based on at least one of the physical information about the vehicle, the information about the vehicle speed, and the information about the gradient of the road on which the vehicle is traveling. Here, the physical information of the vehicle may include information such as the length, width, and drive type (e.g., FF, FR, or 4WD) of the vehicle. Or, the first angular range may be determined by a rated value. In one example, the first angular range may be five degrees.

[0058] In one embodiment, the steering control device can control the drive shaft so that the road wheel can steer left or right within a first angular range at a first frequency relative to the reference steering angle. The first frequency indicates the speed at which the control unit steers the road wheel left or right. The first frequency can, for example, be set to a pre-stored value or determined according to a pre-stored frequency pattern.

[0059] Fig. 10 is a flowchart illustrating one embodiment of controlling a drive shaft in a steering control method of the disclosure. When the drive shaft is controlled so that the road wheel can steer left or right within the first angular range 420 with respect to the reference steering angle 410, the steering control device 120 of the disclosure may be controlled so that the steering state information about the road wheel is not returned to the steering wheel.

[0060] In the SBW system, since an input side (steering column device) including the steering wheel and steering column and an output side (steering rack device) including the road wheel and rack are not physically connected and are controlled based on signals generated by the electronic control unit, the steering control device 120 can transmit different control signals to the input side and the output side. Accordingly, the steering control device can control the drive shaft to steer the road wheel while simultaneously controlling that steering control information about the road wheel is not fed back to the steering wheel. In other words, the steering control device does not transmit a control signal to impart steering force to the steering wheel when steering the road wheel. Therefore, since no steering force is applied to the steering wheel, no changes occur in the steering wheel.

[0061] Since the steering wheel is not moved even when the steering control device 120 of the disclosure steers the road wheel to the left or right to increase traction, it is possible to increase driving stability without causing discomfort to the driver or passenger.

[0062] Fig. 11 is a flowchart showing another embodiment of controlling a drive shaft in a steering control method of the disclosure. The road wheels include front road wheels and rear road wheels. In one embodiment, the steering control device 200 may control the drive shaft so that the front road wheels can steer left or right within a second angular range 510 with respect to the reference steering angle, and so that the rear road wheels can steer left or right within a third angular range 520 with respect to the reference steering angle. In other words, in one embodiment, the front road wheels and the rear road wheels may be controlled with different setting values.

[0063] In one example, the second angular range 510 may be set smaller than the third angular range 520. In another example, the second angular range 610 may be set larger than the third angular range 620. Or, the ratio of the second angular range to the third angular range may be preset, and the steering control device 200 may determine the second angular range and the third angular range according to the preset ratio. The steering control device 200 may steer the front road wheel and the rear road wheel of the vehicle in different ranges, thus efficiently increasing traction.

[0064] Fig. 12 is a flowchart illustrating another embodiment of controlling a drive shaft in a steering control method of the disclosure. In one embodiment, the steering control device 120 may determine whether the steering angle of the steering wheel is identical to the reference steering angle. If it is determined that the steering angle of the steering wheel does not match the reference steering angle, the steering control device 120 may stop controlling the drive shaft so that the road wheel can steer left or right within the first angle range and may control the drive shaft to follow the steering angle of the steering wheel.

[0065] Specifically, the steering control device 120 may receive steering angle information about the steering wheel from the steering angle sensor or another control unit or an external device outside the vehicle via the communication unit, e.g., the V2X communication unit, in real time or at regular intervals. The steering control device 120 may determine that the vehicle is skidding and, when the vehicle is skidding, determine that the steering angle information about the steering wheel is the reference steering angle 710, and then determine whether the steering angle information about the steering wheel obtained from the sensor is identical to the reference steering angle 710. Determining that the steering angle of the steering wheel is not identical to the reference steering angle 710 means that the driver has controlled the steering wheel or that the autonomous driving device or system has controlled the steering.This allows the driver or autonomous driving device or system to determine that they intend to steer. Therefore, if it is determined that the steering angle of the steering wheel does not match the reference steering angle, the steering control device 200 can stop controlling the drive shaft to allow the road wheel to steer left or right within the first angle range and control the drive shaft to follow the steering angle of the steering wheel.

[0066] When the vehicle skids, the drive shaft is controlled to steer the road wheels left or right with respect to the current steering angle of the steering wheel, increasing traction on the low-friction road surface, such as a rainy or snowy road, and thus ensuring stable handling.

[0067] Fig. 13 is a view showing a configuration of a steering system 1300 according to an embodiment of the disclosure.

[0068] Referring to Fig. 13, the steering system of the disclosure may include an input device 1310 that detects a steering angle of a steering wheel of a vehicle, an output device 1330 that drives a road wheel of the vehicle, and a control unit 1320 that determines whether the vehicle is skidding, determines the current steering angle of the steering wheel as a reference steering angle when it is determined that the vehicle is skidding, and controls a drive shaft to steer the road wheel left or right within a first angular range with respect to the reference steering angle.

[0069] The input device 1310 may receive a steering control signal for the vehicle from the driver of the vehicle or an autonomous driving device or system, and the output device 1330 may control the road wheel of the vehicle according to the steering control signal received from the input device.

[0070] The input device 1310, i.e., a steering column unit, may specifically include the steering wheel, a steering shaft, a steering angle sensor that detects the steering angle of the steering wheel, a torque sensor that detects the torque of the steering wheel steering shaft, and a reaction force motor that supplies the torque of the reaction force corresponding to the rotation of the steering wheel. The output device 1330 may include the road wheel, the rack, and a steering output sensor that can detect the rotation angle of the road wheel, a steering motor that generates an assist force to rotate the road wheel, a steering motor position sensor that detects the position of the steering motor rotation shaft, and a rack position sensor that detects the position of the rack.

[0071] The control unit 1330 may be implemented in hardware with at least one electrical component capable of processing data and performing other functions, such as controllers, microcontrollers, and microprocessors (e.g., computers).

[0072] The control unit 1330 determines whether the vehicle is skidding, and if it is determined that the vehicle is skidding, it determines the current steering angle of the steering wheel as the reference steering angle and controls the drive shaft so that the road wheel can steer left or right within a first angle range with respect to the reference steering angle. The configuration of the control unit 1330 may be the configuration of the steering control device of Fig. 2. Accordingly, in describing the control unit 1330 of the steering system of the disclosure, reference may be made to the description of the steering control device of Fig. 2 to 7 are referred to.

[0073] The terms "system," "processor," "controller," "component," "module," "interface," "model," and "unit" described above can generally refer to computer-related hardware, a combination of hardware and software, software, or executing software. The components described above can include, but are not limited to, processes controlled by a processor, processors, controllers, control processors, entities, threads of execution, programs, and / or computers. For example, both an application executed by a control unit or processor and the control unit or processor can be the components. One or more components can be located in a process and / or thread of execution, and the components can be located in one system or distributed across two or more systems.

[0074] When an element "comprises," "includes," or "has" another element, the element may further include, but not exclude, the other element, and the terms "comprise," "include," and "have" should be construed as not precluding the possibility that one or more features, numbers, steps, operations, elements, parts, or combinations thereof may be present or added. All scientific and technical terms used herein may have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined.It is further understood that terms, such as those defined in dictionaries, should be interpreted so that their meaning is consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless expressly defined herein.

[0075] The above description has been presented to enable a person skilled in the art to implement and utilize the technical spirit of the present disclosure and has been provided in the context of a specific application and its requirements. Various modifications, additions, and substitutions of the described embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the independent claims.

Claims

[1] Steering control device (200) comprising: a steering angle determination unit (220) that determines a current steering angle of a steering wheel (111) as a reference steering angle; a control unit (230) which controls a drive shaft to steer a road wheel (131) to the left or right within a first angular range (320) with respect to the reference steering angle; and a slip determination unit (210) which determines whether a vehicle is slipping, characterized by , that in a steer-by-wire system in which a steering column device comprising the steering wheel and a steering column and a rack device comprising the road wheel (131) and a rack are not physically connected, when it is determined that the vehicle is slipping, the steering angle determination unit (220) determines the current steering angle of the steering wheel (111) as the reference steering angle and the control unit (230) controls the drive shaft to steer the road wheel (131) to the left or right within the first angle range (320), wherein the first angle range (320) is determined based on at least one of physical information about the vehicle, speed information about the vehicle, and gradient information about a road on which the vehicle is traveling. [2] Steering control device according to claim 1, characterized bythat the control unit (230) controls such that the steering state information about the road wheel (131) is not returned to the steering wheel (111) when the drive shaft is controlled such that the road wheel (131) is steered to the left or right within the first angular range (320) with respect to the reference steering angle. [3] Steering control device according to claim 1 or 2, characterized by in that the slip determination unit (210) is configured to determine whether slippage occurs on the drive shaft of the vehicle using vehicle speed information, information on a rotational speed of the road wheel detected by a road wheel brake shaft, and information detected by a vehicle inertia sensor. [4] Steering control device according to one of claims 1-3, characterized bythat the control unit (230) controls the drive shaft so that the road wheel (131) is steered to the left or right within the first angular range (320) at a first frequency with respect to the reference steering angle. [5] Steering control device according to claim 4, characterized by that the first frequency is set to a pre-stored value or is determined according to a pre-stored frequency pattern. [6] Steering control device according to one of claims 1-5, characterized by in that the road wheel (131) comprises a front road wheel and a rear road wheel, and wherein the control unit (230) controls the drive shaft to enable the front road wheel to steer left or right within a second angular range with respect to the reference steering angle, and to enable the rear road wheel to steer left or right within a third angular range with respect to the reference steering angle. [7] Steering control device according to one of claims 1-6, characterized by that the steering angle determination unit (220) determines whether the steering angle of the steering wheel (111) is identical to the reference steering angle, and wherein, if it is determined that the steering angle of the steering wheel (111) is not identical to the reference steering angle, the control unit (230) stops controlling the drive shaft to allow the road wheel (131) to steer to the left or right within the first angle range (320) with respect to the reference steering angle, and controls the drive shaft to allow the drive shaft to follow the steering angle of the steering wheel (111). [8] Steering control method comprising: a steering angle determination step (S820) that determines a current steering angle of a steering wheel (111) as a reference steering angle; a control step (S830) that controls a drive shaft to steer a road wheel (131) to the left or right within a first angular range (320) with respect to the reference steering angle; and a slip determination step (S810) for determining whether a vehicle is slipping; characterized by , that in a steer-by-wire system in which a steering column device comprising the steering wheel and a steering column and a rack device comprising the road wheel (131) and a rack are not physically connected, when it is determined that the vehicle is slipping, the current steering angle of the steering wheel (111) is determined as the reference steering angle in the steering angle determination step (S820) and the drive shaft is controlled in the control step (S830) to steer the road wheel (131) to the left and right within the first angle range (S820), wherein the first angular range (320) is determined based on physical information about the vehicle and / or speed information about the vehicle and / or gradient information about a road on which the vehicle is moving. [9] The steering control method according to claim 8, wherein the control step (S830) controls that the steering state information about the road wheel (131) is not returned to the steering wheel (111) when the drive shaft is controlled so that the road wheel (131) is steered to the left or right within the first angular range (320) with respect to the reference steering angle. [10] The steering control method according to claim 8 or 9, wherein the control step (S830) controls the drive shaft so that the road wheel (131) is steered to the left or right within the first angular range (320) at a first frequency with respect to the reference steering angle. [11] The steering control method according to any one of claims 8 to 10, wherein the road wheel (131) comprises a front road wheel and a rear road wheel, and wherein the control step (S830) controls the drive shaft to allow the front road wheel to steer left or right within a second angular range with respect to the reference steering angle and to allow the rear road wheel to steer left or right within a third angular range with respect to the reference steering angle. [12] A steering control method according to any one of claims 8 to 11, wherein the steering angle determining step (S820) determines whether the steering angle of the steering wheel (111) is identical to the reference steering angle, and when it is determined that the steering angle of the steering wheel (111) is not identical to the reference steering angle, the control step (S830) for controlling the drive shaft to allow the road wheel (131) to steer to the left or right within the first angle range (320) with respect to the reference steering angle stops, and the drive shaft is controlled so that the drive shaft can follow the steering angle of the steering wheel (111). [13] Steering system (1300), comprising: an input device (1310) that detects the steering angle of a steering wheel of a vehicle; an output device (1330) that drives a wheel (131) of the vehicle; and a control unit (1320) which determines a current steering angle of the steering wheel (111) as a reference steering angle and controls a drive shaft to thereby steer the road wheel (131) to the left or right within a first angular range (320) with respect to the reference steering angle; characterized byin that the control unit (1320) further determines whether the vehicle is skidding, wherein, in a steer-by-wire system in which a steering column device comprising the steering wheel and a steering column, and a rack device comprising the road wheel (131) and a rack are not physically connected, when it is determined that the vehicle is skidding, determines the current steering angle of the steering wheel (111) as a reference steering angle, and controls the drive shaft to thereby steer the road wheel (131) to the left or right within the first angular range (320) with respect to the reference steering angle, wherein the first angular range (320) is determined based on at least one of physical information about the vehicle, speed information about the vehicle, and slope information about a road on which the vehicle is traveling.

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