Steer-by-wire system control apparatus and method

Abstract

A steer-by-wire system control device and method are proposed. The device includes: a torque superposition control module configured to determine a target steering angle using a torque command input from a lane keeping assist system; and an actuator control module configured to control the position of a rack according to the target steering angle, thereby controlling the vehicle's driving direction.

Description

Technical Field

[0001] Exemplary embodiments of this disclosure relate to steer-by-wire system control devices and methods, and more particularly to steer-by-wire system control devices and methods capable of generating a steering angle command corresponding to a torque command received from a lane keeping assist system and using the generated steering angle command to control the steering of a vehicle. Background Technology

[0002] Steer-by-wire (SBW) is a steering system in which the vehicle's steering wheel and front wheels are mechanically disconnected from each other.

[0003] The SBW system receives the rotation signal from the steering wheel as its input through the electronic control unit (ECU), and can steer the vehicle by operating the steering motor connected to the drive wheels based on the input rotation signal.

[0004] The mechanical connection structure used in the steering system in related technologies has been removed from the SBW system. Therefore, the SBW system offers advantages such as increased layout freedom depending on the steering system configuration, improved fuel efficiency, and suppression of reverse input disturbances from the wheels.

[0005] Lane Keeping Assist System (LKAS) is a system that uses sensors to detect the driving lane and generates torque commands based on the detected lane position information to prevent the vehicle from leaving its lane.

[0006] LKAS, a device that uses torque superposition, sends torque commands to the steering system. Upon receiving a torque command, the steering system adds that command to its output. The torque generated by this superposition is then used to change the vehicle's direction, thereby achieving control objectives such as staying within the driving lane.

[0007] Examples of related technologies are disclosed in Korean patent application No. 10-2020-0041399 (April 22, 2020), entitled "WHEEL ALIGNING METHOD AND SYSTEM FOR STEER BY WIRE SYSTEM". Summary of the Invention

[0008] In related technologies, the steering wheel of the steering force actuator (SFA) rotates in response to torque commands. The steering angle command of the rotating SFA is transmitted to the rack steering actuator (RSA), thereby changing the position of the rack and thus the vehicle's direction of travel. To change the rack position in this way, the SFA's steering wheel is first rotated, resulting in a time delay. The problem is that it is difficult to precisely control the rack position.

[0009] Various embodiments relate to steer-by-wire system control devices and methods that can generate steering angle commands corresponding to torque commands received from a lane keeping assist system, and use the generated steering angle commands to control the position of the rack of the RSA.

[0010] In one embodiment, the steer-by-wire system control device includes: 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 the position of a rack based on the target steering angle, thereby controlling the vehicle's direction of travel.

[0011] In this device, the steer-by-wire system control device may also include a steering wheel control module configured to control the steering reaction force of the steering wheel based on torque commands input from the lane keeping assist system.

[0012] In this device, both the steering wheel control module and the torque superposition control module can receive torque commands from the lane keeping assist system and can operate independently of each other.

[0013] In this device, the steering wheel control module can determine the 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 the reaction force drive unit based on the target steering reaction force.

[0014] In this device, the torque superposition control module may include: a set steering angle determination unit configured to determine a set steering angle using a 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 set steering angle determined by the set steering angle determination unit in the current steering angle.

[0015] In another embodiment, the steer-by-wire system control method includes: 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 the position of a rack by an actuator control module based on the target steering angle, thereby controlling the vehicle's driving direction.

[0016] In this method, the steer-by-wire system control method may further include controlling the steering reaction force of the steering wheel by a steering wheel control module based on a torque command input from the lane keeping assist system.

[0017] In this method, both the steering wheel control module and the torque superposition control module can receive torque commands from the lane keeping assist system and can operate independently of each other.

[0018] In this method, when controlling the steering reaction force of the steering wheel, the steering wheel control module can determine the 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 the reaction force drive unit according to the target steering reaction force.

[0019] In this method, determining the target steering angle may include: determining a set steering angle using a torque command input from the lane keeping assist system; and determining the target steering angle by reflecting the set steering angle in the current steering angle.

[0020] The SBW system control device and method provided according to one aspect of this disclosure can generate a steering angle command corresponding to a torque command received from a lane keeping assist system, and control the vehicle steering using the generated steering angle command. Therefore, the control accuracy and responsiveness of the rack position can be improved, and the performance and marketability of the lane keeping assist system can be enhanced. Attached Figure Description

[0021] Figure 1 This is a view showing an SBW system control device installed according to a first embodiment of the present disclosure.

[0022] Figure 2 This is a block diagram illustrating the configuration of an SBW system control device according to a first embodiment of the present disclosure.

[0023] Figure 3 This is a flowchart illustrating an SBW system control method according to a second embodiment of the present disclosure. Detailed Implementation

[0024] As is customary in the relevant art, some exemplary embodiments may be illustrated in the accompanying drawings as functional blocks, units, and / or modules. Those skilled in the art will understand that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuitry, such as logic circuits, discrete components, processors, hardwired circuitry, memory elements, wiring connections, etc. When blocks, units, and / or modules are implemented by processors or similar hardware, they can be programmed and controlled using software (e.g., code) to perform the various functions discussed herein. Alternatively, each block, unit, and / or module may be implemented by dedicated hardware or a combination of dedicated hardware to perform some functions, and by a processor (e.g., one or more programming processors and associated circuitry) to perform other functions. Without departing from the scope of the inventive concept, each block, unit, and / or module of some exemplary embodiments may actually be divided into two or more interacting and separate blocks, units, and / or modules. Furthermore, blocks, units, and / or modules of some exemplary embodiments may be physically combined into more complex blocks, units, and / or modules without departing from the scope of the inventive concept.

[0025] The SBW system control apparatus and method according to the first and second embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. For clarity and convenience, the thickness of lines and the dimensions of component elements may be exaggerated in the drawings. Furthermore, terms defined by consideration of the function of the component elements according to the present disclosure will be used below, and these terms may vary according to the intent of the user or administrator or practice in the art. Therefore, the terminology should be defined in the context of this specification.

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

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

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

[0029] LKAS detects the driving lane and generates a torque command based on the detected lane position information. The generated torque command is then transmitted to the steer-by-wire (SBW) system to prevent the vehicle from leaving its driving lane.

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

[0031] refer to Figure 1 According to the first embodiment of the present disclosure, the SBW system control device includes a torque superposition control module 100, a steering wheel control module 200, and an actuator control module 300.

[0032] exist Figure 1 In the attached diagram, reference numeral 20 indicates the steering column.

[0033] The steering wheel control module 200 receives torque commands from LKAS and uses these torque commands to control the 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 an appropriate reaction force through the reaction force drive unit 40, thereby providing the driver with a smooth steering feel.

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

[0036] That is, the steering wheel control module 200 applies a reaction force consistent with the torque command from LKAS to the steering reaction force of the steering wheel 10. Therefore, the torque of the steering wheel 10 increases in the direction in which the vehicle can stay in its lane.

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

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

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

[0040] That is, both the steering wheel control module 200 and the torque superposition control module 100 receive torque commands from the LKAS. In this case, the steering wheel control module 200 controls the steering reaction force of the steering wheel 10 using the torque command as described above, and the torque superposition control module 100 generates a 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 via the steering wheel control module 200, and as the steering wheel 10 rotates, the actuator control module 300 controls the position of the rack 60. Therefore, there is a problem that it is difficult to accurately control the position of the rack 60.

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

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

[0044] The steering angle setting unit 110 determines the steering angle using a torque command input from LAKS.

[0045] You can create a lookup table or equation to determine the set steering angle using torque commands input from LKAS.

[0046] Therefore, when a torque command is input from LKAS, the steering angle setting unit 110 can look up the steering angle corresponding to the torque command in the lookup table or determine the steering angle by substituting the torque command into the equation.

[0047] The target steering angle determination unit 120 determines the target steering angle by reflecting the set steering angle determined by the set steering angle determination unit 110 in the 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 set steering angle determined by the set steering angle determination unit 110 to the current steering angle.

[0049] The current steering angle can be measured by the steering angle sensor 30, but is not limited to being measured by the steering angle sensor 30.

[0050] The actuator control module 300 drives the rack drive unit 50 connected to the front wheel W according to the rotation signal of the steering wheel 10, so as to steer the vehicle.

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

[0052] The gearbox includes a pinion that receives rotational force from a universal joint and a rack rod on which the pinion meshes with a rack 60. When the pinion rotates, the rack 60 causes the rack rod to move linearly in the left-right direction. The force generated by the linear motion of the rack rod in the left-right direction is then transmitted to the front wheel W through a tie rod and a ball joint. This changes the vehicle's direction of travel.

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

[0054] The following will refer to Figure 3 The SBW system control method according to the second embodiment of the present disclosure is described in detail.

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

[0056] refer to Figure 3 LKAS first detects the driving lane, and then generates a torque command based on the detected driving lane position information.

[0057] 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 reaction force by adding the steering reaction force consistent with the torque command received from LKAS to the current steering reaction force of the steering wheel 10 (S20).

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

[0060] The steering angle setting unit 110 determines the setting steering angle using the torque command input from LKAS (S40).

[0061] In this case, the steering angle determination unit 110 can look up the steering angle corresponding to the torque command input from LKAS in the lookup table or determine the steering angle by substituting the torque command into the corresponding equation.

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

[0063] Subsequently, the target steering angle determination unit 120 determines the target steering angle by adding the set steering angle determined by the set 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 based on the target steering angle determined by the target steering angle determination unit 120, thereby controlling the driving direction of the vehicle (S70).

[0066] In this way, the SBW system control device and method according to the first and second embodiments of this disclosure can generate a steering angle command corresponding to the torque command received from the LKAS, and use the generated steering angle command to control the vehicle steering. Therefore, the control accuracy and control responsiveness of the rack 60 position can be improved, and the performance and marketability of the LKAS can be enhanced.

[0067] The technical ideas of this disclosure described herein can be implemented in the form of, for example, methods, processes, apparatus, software programs, data streams, or signals. While the above features are described only in the context of implementation in a single form (e.g., described as implemented only as a method), they can also be implemented in different forms (e.g., as an apparatus or a program). The apparatus can be implemented in the form of suitable hardware, software, firmware, etc. For example, the method can be implemented in an apparatus such as a computer, microprocessor, or processor, which generally refers to a processing device such as an integrated circuit or programmable logic device. The apparatus also includes computers, cellular phones, portable / personal information terminals (personal digital assistants, "PDAs"), and other communication devices that facilitate information communication between end users.

Claims

1. A control device for a steer-by-wire system, comprising: The torque superposition control module is configured to determine the target steering angle based on the torque command input from the lane keeping assist system; An actuator control module is configured to control the position of the rack according to the target steering angle, thereby controlling the driving direction of the vehicle; and A steering wheel control module configured to control the steering reaction force of the steering wheel based on the torque command input from the lane keeping assist system.

2. The steer-by-wire system control device according to claim 1, wherein Both the steering wheel control module and the torque superposition control module receive the torque command from the lane keeping assist system and operate independently of each other.

3. The steer-by-wire system control device according to claim 1, wherein The steering wheel control module determines the target steering reaction force by reflecting the torque command input from the lane keeping assist system into the steering reaction force of the steering wheel, and controls the reaction force drive unit based on the target steering reaction force.

4. The steer-by-wire system control device according to claim 1, wherein The torque superposition control module includes: A steering angle determination unit is configured to determine a set steering angle using the torque command input from the lane keeping assist system; and A target steering angle determination unit is configured to determine a target steering angle by reflecting the set steering angle determined by the set steering angle determination unit in the current steering angle.

5. A control method for a steer-by-wire system, comprising: The torque superposition control module determines the target steering angle based on the torque command input from the lane keeping assist system; The actuator control module controls the position of the rack according to the target steering angle, thereby controlling the vehicle's driving direction; and The steering wheel control module controls the steering reaction force of the steering wheel based on the torque command input from the lane keeping assist system.

6. The steer-by-wire system control method according to claim 5, wherein Both the steering wheel control module and the torque superposition control module receive torque commands from the lane keeping assist system and operate independently of each other.

7. The steer-by-wire system control method according to claim 5, wherein When controlling the steering reaction force of the steering wheel, the steering wheel control module determines the target steering reaction force by reflecting the torque command input from the lane keeping assist system into the steering reaction force of the steering wheel, and controls the reaction force drive unit according to the target steering reaction force.

8. The steer-by-wire system control method according to claim 5, wherein The determination of the target steering angle includes: The set steering angle is determined using a torque command input from the lane keeping assist system; and The target steering angle is determined by reflecting the set steering angle in the current steering angle.

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