STEER-BY-WIRE SYSTEM CONTROL DEVICE AND METHOD

Abstract

Steer-by-wire system control device which features: a torque superposition control module (100) configured to determine a target steering angle based on a torque command input from a lane keeping assist system; and an actuator control module (300) that is configured to control a position of a rack (60) according to the target steering angle and thus to control a direction of travel of a vehicle.

Description

BACKGROUND

[0001] Exemplary embodiments of the present disclosure relate to a steer-by-wire system control device and method, and in particular to a steer-by-wire system control device and method capable of generating a steering angle command corresponding to a torque command received from a lane keeping assist system, and of controlling vehicle steering with the generated steering angle command. BACKGROUND DISCUSSION

[0002] A steer-by-wire (SBW) system is a steering system in which the steering wheel and the front wheel of a vehicle are mechanically separated from each other.

[0003] The SBW system receives a rotation signal from a steering wheel as an input signal via an electronic control unit (ECU) and can steer the vehicle by actuating a steering motor connected to a drive wheel based on the input rotation signal.

[0004] A mechanical linkage structure, which is used in prior art steering systems, is eliminated in the SBW system. Therefore, the SBW system offers advantages such as increased design freedom for steering system configurations, improved fuel consumption, and suppression of disturbances originating from a vehicle wheel in the opposite direction.

[0005] A Lane Keeping Assistance System (LKAS) is a system that detects a lane through a sensor, generates a torque command according to position information of the detected lane, and thus prevents the vehicle from leaving the lane.

[0006] The LKAS, a device that uses torque superposition, sends the torque command to a steering system. Upon receiving the torque command, the steering system adds an output corresponding to the torque command to one of its outputs. The torque resulting from this addition changes the vehicle's direction of travel, thus achieving the control objective, such as maintaining lane position.

[0007] An example of related prior art is disclosed in the Korean application publication KR 10 2020 0 041 399 A (22 April 2020) entitled “WHEEL ALIGNING METHOD AND SYSTEM FOR STEER BY WIRE SYSTEM”.

[0008] From DE 10 2019 208 395 A1, a method for influencing the lateral dynamics of a vehicle is known. The vehicle comprises a steering system with at least one steering actuator. The steering actuator is controlled in at least one operating state by a control signal from a driver assistance function. The control signal is limited situation-specifically depending on a steering speed parameter.

[0009] A steer-by-wire steering system with lane keeping support is known from DE 11 2010 003 977 B4.

[0010] In the prior art, a steering wheel of a steering force actuator (SFA) is rotated by a torque command. A steering angle command from the rotated SFA is transmitted to a rack and pinion steering actuator (RSA), thereby changing the position of a rack and pinion, thus changing the direction of travel of a vehicle. To change the position of a rack and pinion in this way, the steering wheel of the SFA is first rotated, resulting in a time delay. A problem arises in that precise control of the rack and pinion position is difficult to achieve.

[0011] Various embodiments relate to a steer-by-wire system control device and method suitable for generating a steering angle command corresponding to a torque command received from a lane keeping assist system and for controlling the position of a rack of an RSA with the generated steering angle command.

[0012] The solution to the aforementioned problem is provided by a steer-by-wire system control device with the features of claim 1 and a steer-by-wire control method with the features of claim 6. Advantageous further developments are set forth in the dependent claims.

[0013] In one embodiment, a steer-by-wire system control device comprises: a torque superposition control module configured to determine a target steering angle based on a torque command input from a lane keeping assist system; and an actuator control module configured to control a position of a rack according to the target steering angle, thereby controlling a vehicle's direction of travel.

[0014] The device may further include a steering wheel control module configured to control a steering wheel's steering response force based on the torque command input from the lane keeping assist system.

[0015] In the device, the steering wheel control module and the torque superposition control module can each receive the torque command from the lane keeping assist system and operate independently of each other.

[0016] In the device, the steering wheel control module can determine a target steering reaction force by reflecting the torque command input from the lane keeping assist system in the steering reaction force of the steering wheel, and can control a reaction force drive unit according to the target steering reaction force.

[0017] The device may include the torque superposition control module: an adjustment steering angle determination unit configured to determine an adjustment steering angle using the torque command input from the lane keeping assist system; and a target steering angle determination unit configured to determine a target steering angle by reflecting the adjustment steering angle determined by the adjustment steering angle determination unit into an actual steering angle.

[0018] In another embodiment, a steer-by-wire system control method comprises: determining a target steering angle by a torque superposition control module based on a torque command input from a lane keeping assist system; and controlling a position of a rack by an actuator control module in accordance with the target steering angle and thus a direction of travel of a vehicle.

[0019] In this procedure, the steer-by-wire system control method can further include controlling a steering response force of a steering wheel by a steering wheel control module based on the torque command input from the lane keeping assist system.

[0020] In this process, the steering wheel control module and the torque superposition control module can each receive a torque command from the lane keeping assist system and operate independently of each other.

[0021] In this method, the steering wheel control module can determine a target steering reaction force when controlling the steering wheel's steering reaction force by reflecting the torque command input from the lane keeping assist system into the steering wheel's steering reaction force, and can control a reaction force drive unit according to the target steering reaction force.

[0022] The procedure for determining the target steering angle may include: determining a setting steering angle using the torque command input from the lane keeping assist system; and determining a target steering angle by reflecting the setting steering angle in an actual steering angle.

[0023] The SBW system control device and method provided according to one aspect of the present disclosure are suitable for generating a steering angle command corresponding to a torque command received from a lane keeping assist system and for controlling the vehicle steering with the generated steering angle command. In this way, the accuracy of the rack position control and the responsiveness of the rack's control can be improved, as well as the performance and marketability of a lane keeping assist system. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a view showing that an SBW system control device is installed according to a first embodiment of the present disclosure. Fig. Figure 2 is a block diagram showing a configuration of the SBW system control device according to the first embodiment of the present disclosure. Fig. Figure 3 is a flowchart illustrating an SBW system control procedure according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE ILLUSTRATED EXECUTION FORMS

[0024] As is common in the relevant field, some exemplary embodiments may be represented in the drawings in the form of functional blocks, units, and / or modules. Those skilled in the art will know that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuits such as logic circuits, discrete components, processors, hard-wired circuits, memory elements, wiring connections, and the like. If the blocks, units, and / or modules are implemented by processors or similar hardware, they can be programmed and controlled by software (e.g., code) to perform various functions described herein. Alternatively, each block, unit, and / or module may be implemented by dedicated hardware or as a combination of dedicated hardware for performing some functions and a processor (e.g., a microcontroller).(one or more programmed processors and associated circuits) to execute other functions. Each block, unit, and / or module of some exemplary embodiments can be physically divided into two or more interacting and discrete blocks, units, and / or modules without this deviating from the scope of the inventive concept. Furthermore, blocks, units, and / or modules of some exemplary embodiments can be physically combined to form more complex blocks, units, and / or modules without this deviating from the scope of the inventive concept.

[0025] An SBW system control device and method according to a first and second embodiment of the present disclosure are described in detail below with reference to the accompanying drawings. For the sake of clarity and simplicity, the line thicknesses and sizes of individual elements in the drawings may be exaggerated. Furthermore, a term defined by considering the function of a component according to the present disclosure, to which the term is assigned, is used below and may vary depending on the user's or manager's intent or according to established technical practice. Therefore, the term should be defined in the context of the present description.

[0026] Fig. Figure 1 is a view showing that an SBW system control device is installed according to the first embodiment of the present disclosure. Fig. Figure 2 is a block diagram showing a configuration of the SBW system control device according to the first embodiment of the present disclosure.

[0027] The SBW system control device according to the first embodiment of the present disclosure receives, as input, a torque command from a lane keeping assist system (LKAS) (not shown), generates a steering reaction force according to the input torque command, makes the generated steering reaction force available to a steering wheel 10 and controls a direction of travel of a vehicle.

[0028] The LKAS is a device that uses torque superposition.

[0029] The LKAS detects a lane, generates a torque command according to position information of the detected lane, transmits the generated torque command to a steer-by-wire (SBW) system and thus prevents the vehicle from leaving the lane.

[0030] The SBW system is a steering system in which the steering wheel 10 and a front wheel W of the vehicle are mechanically separated from each other.

[0031] In relation to Fig. 1 The SBW system control device according to the first embodiment of the present disclosure comprises a torque superposition control module 100, a steering wheel control module 200 and an actuator control module 300.

[0032] In Fig. 1. Reference number 20 refers to a steering column.

[0033] The steering wheel control module 200 receives a torque command from the LKAS and uses this torque command to control a steering reaction force of the steering wheel 10.

[0034] When the steering wheel is turned, the steering wheel control module 200 provides the driver with a suitable reaction force via a reaction force drive unit 40, thus giving the driver the feeling of smooth steering.

[0035] In this case, the steering wheel control module 200 determines a target steering reaction force by reflecting the torque command input from the LKAS in the steering reaction force of the steering wheel 10 and controlling the reaction force drive unit 40 according to the target steering reaction force.

[0036] This means that the steering wheel control module 200 adds a reaction force to the steering reaction force of the steering wheel 10, which corresponds to the torque command of the LKAS. This increases the torque of the steering wheel 10 in a direction in which the vehicle can remain in its lane.

[0037] The steering wheel control module 200 can be a steering force actuator (SFA) of the SBW system.

[0038] The torque superposition control module 100 determines a target steering angle using the torque command input from the LKAS and transmits the determined target steering angle to the actuator control module 300. In this case, the actuator control module 300 controls a rack and pinion drive unit 50 according to the target steering angle input from the torque superposition control module 100 and thus controls a position of a rack 60, thereby controlling the direction of travel of the vehicle.

[0039] The steering wheel control module 200 and the torque superposition control module 100 each receive the torque command from the LKAS and operate independently of each other.

[0040] This means that the steering wheel control module 200 and the torque superposition control module 100 each receive the torque command from the LKAS. In this case, the steering wheel control module 200, as described above, uses the torque command to control the steering reaction force of the steering wheel 10, and the torque superposition control module 100 generates the target steering angle and transmits the generated target steering angle to the actuator control module 300.

[0041] In the prior art, the steering wheel 10 is rotated by the steering wheel control module 200, and the actuator control module 300 controls the position of the rack 60 with the rotation of the steering wheel 10. This results in a problem in that precise control of the position of the rack 60 is difficult.

[0042] As described above, the steering wheel control module 200 and the torque superposition control module 100 each receive the torque command from the LKAS and operate independently. Therefore, the degree of accuracy of the rack 60 position control and the responsiveness of the control can be improved, and the performance and marketability of the LKAS can be enhanced.

[0043] The torque superposition control module 100 comprises a setting steering angle determination unit 110 and a target steering angle determination unit 120.

[0044] The steering angle setting unit 110 determines a steering angle setting using the torque command entered by the LKAS.

[0045] A lookup table or equation can be created to determine a steering angle setting using the torque command entered by the LKAS.

[0046] When the torque command is entered by the LKAS, the steering angle setting unit 110 can look up the steering angle setting that corresponds to the torque command in the lookup table or determine the steering angle setting by inserting the torque command into the equation.

[0047] The target steering angle determination unit 120 determines the target steering angle by mirroring the set steering angle determined by the setting steering angle determination unit 110 into a current steering angle. The target steering angle determination unit 120 transmits the determined target steering angle to the actuator control module 300.

[0048] In this case, the target steering angle determination unit 120 determines the target steering angle by adding the setting steering angle determined by the adjustment steering angle determination unit 110 to the current steering angle.

[0049] The current steering angle can be measured by a steering angle sensor 30 and is not limited to measurement by the steering angle sensor 30.

[0050] The actuator control module 300 controls the rack and pinion drive unit 50 connected to the front wheel W on the basis of a rotation signal from the steering wheel 10 in such a way that the vehicle is steered.

[0051] In this case, the actuator control module 300 controls the rack and pinion drive unit 50 according to the target steering angle determined by the target steering angle determination unit 120 and thus regulates the vehicle steering.

[0052] A transmission comprises a gear unit that receives a rotational force from a universal joint and a rack and pinion on which the rack 60, with which the gear unit engages, is formed. As the gear unit rotates, the rack 60 moves the rack and pinion in a straight line in a left-right direction. At this point, a force generated by the linear movement of the rack and pinion in the left-right direction is transmitted to the front wheel W via a tie rod and a ball joint. This changes the direction of travel of the vehicle.

[0053] The actuator control module 300 can be a rack and pinion steering actuator (RSA) or a road wheel actuator (RWA) of the SBW system.

[0054] An SBW system control method according to a second embodiment of the present disclosure is described below with reference to Fig. 3 described in detail.

[0055] Fig. Figure 3 is a flowchart illustrating the SBW system control procedure according to the second embodiment of the present disclosure.

[0056] With reference to Fig. 3. The LKAS first recognizes a lane and then generates the torque command according to position information of the recognized lane.

[0057] The LKAS transmits the generated torque command to the steering wheel control module 200 and the torque superposition control module 100 (S10).

[0058] The steering wheel control module 200 determines the target steering force by adding a steering reaction force to the steering reaction force of the steering wheel 10 according to the torque command received from the LKAS (S20).

[0059] Subsequently, the steering wheel control module 200 controls the reaction force drive unit 40 according to the determined target steering reaction force and consequently controls the steering reaction force of the steering wheel 10 (S30).

[0060] The steering angle setting unit determines the steering angle setting using the torque command (S40) entered by the LKAS.

[0061] In this case, the steering angle setting unit 110 can look up the steering angle setting in the lookup table according to the torque command entered by the LKAS, or determine the steering angle setting by inserting the torque command into the corresponding equation.

[0062] In addition, the target steering angle determination unit 120 receives a steering angle (S50) measured by the steering angle sensor 30.

[0063] The target steering angle determination unit 120 then determines the target steering angle by adding the setting steering angle determined by the adjustment steering angle determination unit 110 to the current steering angle measured by the steering angle sensor 30 (S60).

[0064] The target steering angle determination unit 120 inputs the target steering angle into the actuator control module 300.

[0065] The actuator control module 300 controls the position of the rack 60 according to the target steering angle determined by the target steering angle determination unit 120 and thus controls the direction of travel of the vehicle (S70).

[0066] In this way, the SBW system control device and method according to the first and second embodiments of the present disclosure are able to generate the steering angle command in accordance with the torque command received from the LKAS and to control the vehicle steering with the generated steering angle command. In this way, the accuracy of the control of the position of the rack 60 and the responsiveness of its control can be improved, and the performance and marketability of the LKAS can be enhanced.

[0067] One way of realizing the technical idea of ​​the present disclosure, as described in this specification, may be, for example, in the form of a method, a process, a device, a software program, a data stream, or a signal. Although the feature described above is only mentioned in connection with realization in a single form (e.g., only in the form of a method), it may also be realized in another form (e.g., in the form of a device or a program). The device may be realized in the form of suitable hardware, software, firmware, or the like. The method may, for example, be realized in a device such as a computer, a microprocessor, or a processor, which generally refers to a processing device such as an integrated circuit or a programmable logic device.The devices also include a computer that facilitates the communication of information between end users, a mobile phone, a portable / personal information terminal (a personal digital assistant ("PDA"), and other communication devices.

Claims

[1] Steer-by-wire system control device comprising: a torque superposition control module (100) configured to determine a target steering angle based on a torque command input from a lane keeping assist system; and an actuator control module (300) that is configured to control a position of a rack (60) according to the target steering angle and thus to control a direction of travel of a vehicle. [2] Steer-by-wire system control device according to claim 1, characterized by , that the steer-by-wire system control device further features: a steering wheel control module (200) configured to control a steering response force of a steering wheel (10) based on the torque command input from the lane keeping assist system. [3] Steer-by-wire system control device according to claim 2, characterized by, that the steering wheel control module (200) and the torque superposition control module (100) each receive the torque command from the lane keeping assist system and operate independently of each other. [4] The steer-by-wire system control device according to claim 2 or 3, characterized by , that the steering wheel control module (200) determines a target steering reaction force by reflecting the torque command input from the lane keeping assist system in the steering reaction force of the steering wheel (10) and controlling a reaction force drive unit (40) according to the target steering reaction force. [5] Steer-by-wire system control device according to any one of claims 1 to 4, characterized by , that the torque superposition control module (100) has: a steering angle setting unit (110) configured to determine a steering angle setting using the torque command input from the lane keeping assist system; and a target steering angle determination unit (120) configured to determine a target steering angle by reflecting the setting steering angle determined by the target steering angle determination unit (120) into an actual steering angle. [6] Steer-by-wire system taxation procedure, which includes: Determining a target steering angle by a torque superposition control module (100) based on a torque command input from a lane keeping assist system; and Control of a position of a rack (60) by an actuator control module (300) according to the target steering angle and thus a direction of travel of a vehicle. [7] Steer-by-wire system control method according to claim 6, characterized by , that the steer-by-wire system includes the following tax procedures: Control of a steering reaction force of a steering wheel (10) by a steering wheel control module (200) on the basis of the torque command input from the lane keeping assist system. [8] Steer-by-wire system control method according to claim 7, characterized by , that the steering wheel control module (200) and the torque superposition control module (100) each receive a torque command from the lane keeping assist system and operate independently of each other. [9] Steer-by-wire system control method according to claim 7 or 8, characterized by , that when controlling the steering reaction force of the steering wheel (10), the steering wheel control module (200) determines a target steering reaction force by reflecting the torque command input from the lane keeping assist system in the steering reaction force of the steering wheel (10) and controlling a reaction force drive unit (40) according to the target steering reaction force. [10] Steer-by-wire system control method according to any one of claims 6 to 9, characterized by , that includes determining the target steering angle: Determining a steering angle setting using the torque command input from the lane keeping assist system; and Determining a target steering angle by reflecting the set steering angle into the current steering angle.

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