Control device and control method for steer-by-wire

Abstract

The present application provides a kind of to be able to realize the control device and control method of steer-by-wire steering both comfort and safety.The present application is with the first motor (12) of the steering wheel (11) via FBA control and the second motor (13) of the steering angle of wheel via RWA control, and the control device (20) of steer-by-wire steering of bidirectional control first motor (12) and second motor (13) can be, it includes: basic SAT (21), which is based on the angle of first motor (12) and vehicle speed and finds out reference torque;And rack force estimation part (22), which is based on the steering angle of wheel and RWA and estimates as the rack force of reaction force.It has the first control mode of the reference torque of control first motor (12) and the second control mode of control first motor (12) based on the reaction force estimated by rack force estimation part (22), based on the output of basic SAT (21) and the output of rack force estimation part (22) switches the first control mode and the second control mode.

Description

Technical Field

[0001] This invention relates to a control device for a steering system, and particularly to a control device and method for steer-by-wire. Background Technology

[0002] In existing technology, the steering system mechanically connects the steering rack to the steering wheel. In this system, the reaction force generated in the tires due to interaction with the road surface is transmitted to the driver (driver) via the mechanical connection as a reaction force on the steering wheel. This reaction force is indispensable for the driver to safely control the vehicle under any road conditions.

[0003] For example, SAT (Self-aligning torque) and the interference of obstacles on steering can be cited as reaction forces.

[0004] Steer-by-wire (SBW) is a system that does not have a mechanical connection between the steering wheel and the steering rack, but instead uses communication and actuators. Therefore, the reaction force generated in the tires cannot be mechanically transmitted to the driver, so it is necessary to simulate the same steering system movements as before in manual driving mode. The actuator in the steering wheel, the feedback actuator (FBA), applies the simulated reaction force to the driver. The actuator connected to the steering rack, the road wheel actuator (RWA), provides the steering wheel with the force that moves the steering rack left and right. The FBA and RWA are controlled by an embedded computer, the Electronic Control Unit (ECU).

[0005] As a technology related to such SBW, for example, the technology described in Patent Document 1 is known. Patent Document 1 discloses a method for calculating the feedback torque of the steering wheel based on the deviation between the steering torque applied to the steering rack and the steering torque below the minimum torque.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: US Patent Publication No. 2020 / 0023894 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, the current SBW and the technology disclosed in Patent Document 1 primarily focus on reproducing existing steering systems. This includes the fact that reaction forces from road noise are always fed back to the driver, raising concerns about potentially uncomfortable steering feel.

[0011] Therefore, the present invention provides a control device and control method for steer-by-wire that can achieve both comfort and safety.

[0012] Methods for solving problems

[0013] To address the aforementioned issues, the steer-by-wire control device of the present invention is a steer-by-wire control device having a first motor that controls the steering wheel via a feedback actuator and a second motor that controls the steering angle of the wheels via a driving wheel actuator, and capable of bidirectional control of the first motor and the second motor. The device is characterized by comprising: a basic SAT torque unit that calculates the simulated feedback actuator torque based on the angle of the first motor and the vehicle speed; and a rack force calculation unit that calculates the rack force as a reaction force based on the steering angle of the wheels and the driving wheel actuator. This unit has a first control mode that controls the simulated feedback actuator torque of the first motor, and a second control mode that controls the first motor based on the reaction force calculated by the rack force calculation unit. The first control mode and the second control mode are switched based on the output of the basic SAT unit and the output of the rack force calculation unit.

[0014] Furthermore, the steer-by-wire control method of the present invention is a steer-by-wire control method having a first motor that controls the steering wheel via a feedback actuator and a second motor that controls the steering angle of the wheels via a driving wheel actuator, and capable of bidirectional control of the first motor and the second motor. The method is characterized in that: a basic SAT unit calculates the simulated feedback actuator torque based on the angle of the first motor and the vehicle speed; a rack force calculation unit calculates the rack force as a reaction force based on the steering angle of the wheels and the driving wheel actuator; and based on the output of the basic SAT unit and the output of the rack force calculation unit, switches between a first control mode that controls the simulated feedback actuator torque of the first motor and a second control mode that controls the first motor based on the reaction force calculated by the rack force calculation unit.

[0015] Invention Effects

[0016] According to the present invention, a control device and control method for steer-by-wire that can achieve both comfort and safety can be provided.

[0017] Specifically, the baseline SAT is calculated in analog feedback mode to provide comfortable steering and filter out all unwanted noise from the road surface. The Bilateral Control components (BLC) mode provides tactile feedback from the road surface to alert the driver when necessary (e.g., generating a stronger reaction force in FBA if the RWA cannot steer further due to the presence of an obstacle).

[0018] Other issues, structures, and effects not described above will be explained through the following description of the implementation methods. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the SBW system using the control device of the present invention.

[0020] Figure 2 This is a block diagram of the control device of Embodiment 1 of the present invention.

[0021] Figure 3 This is a flowchart of the SBW system of the control device in Application Example 1.

[0022] Figure 4 This is a timing diagram indicating when the BLC is ON / OFF.

[0023] Figure 5 This is a diagram showing the relationship between the reaction force observer and the friction model.

[0024] Figure 6 This is a block diagram of the control device of Embodiment 2, which is another embodiment of the present invention.

[0025] Figure 7 This is a block diagram of the control device of Embodiment 3, which is another embodiment of the present invention.

[0026] Figure 8 This is a block diagram of the control device of Embodiment 4, which is another embodiment of the present invention. Detailed Implementation

[0027] First, the SBW system of the steer-by-wire control device of the present invention will be described.

[0028] Figure 1 This is a schematic structural diagram of the SBW system using the control device of the present invention. Figure 1 As shown, the SBW system consists of a steering wheel (hereinafter sometimes referred to as steering wheel) 11, an FBA motor (first motor) 12, an RWA motor (second motor) 13, a ball screw 14, and a rack 15.

[0029] Steering wheel 11 is the steering wheel that the driver can grip, and the driver can input steering commands (steering torque) to indicate the angle of the rack. Mechanical connections are eliminated in the SBW method (there are no mechanical connections), whereas in existing steering methods, there is a mechanical connection between the steering wheel and the steering rack. The simulated reaction force is the force applied to the driver via steering wheel 11 to reproduce the feeling of resistance when steering an existing steering system. Rack 15 is the mechanical connection for steering the driving wheels. External axial force is the force introduced onto rack 15 from the external environment. FBA (first motor) 12 is an electric motor mounted on steering wheel 11 that applies simulated reaction force to the driver. RWA (second motor) 13 is an electric motor used to steering rack 15 according to commands received from FBA. Ball screw 14 is the connection that converts the rotational motion of RWA into the linear motion of rack 15.

[0030] Hereinafter, with the aid of the accompanying drawings, an embodiment of the steer-by-wire control device of the present invention applying the above-described SBW system will be described.

[0031] (Example 1)

[0032] Figure 2 This is a block diagram of the control device of Embodiment 1 of the present invention. Figure 2 As shown, the steer-by-wire control device 20 consists of a basic SAT 21 module, a rack force calculation 22 module, a gain K 23 module, an insensitivity zone 24 module, and a maximum element selection 25 module. Here, the steer-by-wire control device 20 is installed in the ECU. The basic SAT 21 module, rack force calculation 22 module, gain K 23 module, insensitivity zone 24 module, and maximum element selection 25 module are implemented, for example, using a processor such as a CPU (not shown), a ROM storing various programs, RAM temporarily storing data from the calculation process, or an external storage device. The processor reads and executes the various programs stored in the ROM, and saves the execution results, i.e., the calculation results, in the RAM or external storage device. Furthermore, the steer-by-wire control device 20 is not limited to being installed in an ECU; it can also be installed in other electronic control systems.

[0033] The FBA angle is the angle of the steering wheel 11 or the electric motor (FBA motor (first motor) 12) mounted on the steering wheel 11. Vehicle speed is the speed at which the vehicle moves relative to the ground. The basic SAT21 module takes the FBA angle and vehicle speed as input, and selects module 25 for the maximum element to output the FBA torque, which simulates the torque transmitted to the steering wheel by the SAT (Self-aligning torque) generated by the rotating driving wheels (wheels).

[0034] The RWA angle is the angle of the RWA motor (second motor) 13 mounted on the rack 15 or the driving wheel (wheel). The RWA torque is the torque generated by the RWA motor (second motor) 13 mounted on the rack 15 or the driving wheel (wheel). The rack force calculation module 22 is an algorithm used to calculate the direction and magnitude of the force within the rack 15. It takes the RWA angle and RWA torque as input and outputs the calculated rack force to the gain module K23.

[0035] The gain module K23 converts the calculated rack force input from the rack force calculation module 22 into torque converted to the FBA axis and compares the gain with that of the basic SAT21 module. The insensitive band module 24 removes noise from the calculated rack force input from the rack force calculation module 22 and generates a zero output function within a specified region.

[0036] The Maximum Element Selection 25 module outputs a function of the maximum element input, which is either the simulated SAT input from the base SAT21 module, converted to the FBA torque (i.e., the reference torque) or the converted calculated rack force. The FBA torque is the output of the Maximum Element Selection 25 module and is the torque applied to the FBA and steering wheel 11.

[0037] Figure 3 This is a flowchart of the SBW system of the steer-by-wire control device 20 applied in this embodiment.

[0038] By turning the vehicle's ignition on, it begins Figure 3 The process is shown below. In step S101, the SBW system starts. For example, it checks the current FBA angle and RWA angle, and makes the FBA angle consistent with the RWA angle.

[0039] In step S102, the SBW starts working and detects the steering wheel 11 (reference). Figure 1 The angle (steering angle) is converted into a steering angle command for the RWA. In other words, the angle of the steering wheel 11 or the electric motor (FBA motor (first motor) 12) mounted on the steering wheel 11 is detected, i.e., the FBA angle (receiving FBA steering angle data), and the angle command is output from the FBA to the RWA.

[0040] In step S103, the RWA torque required to follow the angle command from the FBA is calculated.

[0041] In step S104, the RWA generates the torque calculated in step S103, and the operating status of the RWA and the vehicle is received. That is, the operating status of the RWA and the vehicle is monitored. In step S105, the rack force calculation 22 (refer to...) of the control device 20 constituting the steer-by-wire system is performed. Figure 2 ) Module calculation for rack 15 (reference) Figure 1The external axial force introduced is used to convert the calculated rack force into FBA torque. Additionally, in step S106, the base SAT21 (reference) Figure 2 The module uses FBA angle and vehicle speed to calculate the FBA torque (reference torque) that simulates the reaction torque caused by SAT.

[0042] In step S107, the converted calculated rack force is compared with the reference torque generated by the basic SAT21 module to determine whether to switch BLC to ON or OFF. Here, BLC is conceived, for example, as a case where FBA is the active controller and RWA is the passive controller. The steering angle (FBA angle) received from the active side FBA is sent as an angle command to the passive side RWA. The passive side RWA operates according to the received angle command. When the driving wheel (wheel) contacts an obstacle, the passive side RWA feeds back the detected force (tactile force) to the active side FBA. The active side FBA transmits the tactile force to the driver via the steering wheel 11. Thus, the two-way control between active and passive controllers is BLC (two-sided control).

[0043] In step S108, it is determined whether BLC is ON or OFF. In step S109, if BLC is ON, the calculated reaction force after conversion of FBA is output, and road tactile feedback is transmitted to the driver via steering wheel 11. On the other hand, in step S110, if BLC is OFF, the reference torque generated by FBA calculated by the basic SAT21 module is calculated, and the calculated reference torque is generated by FBA to provide the driver with a smooth and comfortable steering reaction force.

[0044] In step S111, it is confirmed whether the vehicle's ignition is still ON. That is, it is confirmed whether to continue the process described in steps S102 to S110. If the vehicle's ignition is still ON, the process returns to step S102 and executes the process described in steps S102 to S110. On the other hand, if the vehicle's ignition is OFF, the process ends.

[0045] Figure 4 This is a timing diagram indicating when the BLC is ON / OFF. Figure 4 In the G101, the G101 is based on the SAT 21 (reference). Figure 2 The module's output (reference torque) and the calculation from the rack force 22 (reference) Figure 2This is an example of the timing sequence for comparing the output of the SAT21 module with the calculated rack force. With time on the horizontal axis and force on the vertical axis, the solid line represents the output (reference torque) from the basic SAT21 module, and the dashed line represents the output (calculated rack force) from the rack force calculation 22 module. G102 represents the timing sequence for the BLC switching when the timing sequence for comparing the output (reference torque) from the basic SAT21 module with the output (calculated rack force) from the rack force calculation 22 module is G101. Figure 2 The maximum element selection shown is 25 (reference). Figure 2 The module compares the output (reference torque) from the base SAT21 module with the output (calculated rack force) from the rack force calculation 22 module, and takes the one with the greater value as the FBA torque output. When the calculated rack force is higher than the output (reference torque) from the base SAT21 module, the BLC is turned ON.

[0046] Figure 5 This is a diagram showing the relationship between the reaction force observer and the friction model. Figure 5 In the model, the reaction force observer (RFOB) uses an algorithm to calculate rack force without using a force sensor. The pinion angle is the angle of steering wheel 11 or the converted RWA angle of steering wheel 11. The pinion speed is the ratio of the rotation of the steering angle. Friction is the resistance generated by the object in contact with the object during motion within the RWA. The nominal RWA model is based on the pinion angle used to back-calculate the rack force (reference). Figure 1 The RWA friction model is a model of the forces acting on the rack. It is a nominal model used to calculate frictional forces to improve the accuracy of rack force estimation.

[0047] As described above, according to this embodiment, a steer-by-wire control device capable of achieving both comfort and safety can be provided.

[0048] (Example 2)

[0049] Figure 6 This is a block diagram of the control device of Embodiment 2, another embodiment of the present invention. In this embodiment, the steering-by-wire control device 30, instead of the insensitive band 24 module and the maximum element selection 25 module, has a deviation calculation 31 module, a relay 22 module, a delay 23 module, a switching 34 module, and a transition smoothing 35 module, which differs from Embodiment 1. The same reference numerals are used for the same components as in Embodiment 1, and descriptions that are repeated in Embodiment 1 are omitted.

[0050] like Figure 6As shown, the steer-by-wire control device 30 in this embodiment consists of a basic SAT 21 module, a rack force calculation 22 module, a gain K 23 module, a deviation calculation 31 module, a relay 22 module, a delay 23 module, a switching 34 module, and a transition smoothing 35 module. Here, the steer-by-wire control device 30 is installed in the ECU. The basic SAT 21 module, rack force calculation 22 module, gain K 23 module, deviation calculation 31 module, relay 22 module, delay 23 module, switching 34 module, and transition smoothing 35 module are implemented, for example, using a processor such as a CPU (not shown), a ROM storing various programs, RAM temporarily storing data from the calculation process, or an external storage device. The processor reads and executes the various programs stored in the ROM, and stores the execution result, i.e., the calculation result, in the RAM or external storage device. Furthermore, the steer-by-wire control device 30 is not limited to being installed in an ECU; it can also be installed in other electronic control systems. Additionally, the deviation calculation 31 module, relay 22 module, delay 23 module, and switching 34 module can also be implemented in hardware.

[0051] The deviation calculation module 31 is a subtraction module used to compare or extract the difference between the outputs from the basic SAT21 module and the rack force calculation module 22. The relay module 22 is an anti-sway mechanism used to avoid unnecessary switching between the basic SAT21 module and the rack force calculation module 22. The delay module 23 has the capability to delay even without adjusting the rack 15 (reference). Figure 1 The system introduces external force and continuously selects the BLC mode. Switching module 34 has the function of selecting one of the following outputs: the output from the base SAT21 module (the base torque generated by the FBA), the output from the rack force calculation 22 module (the value that converts the calculated rack force into torque for the FBA), and the output (signal) from the delay 23 module, and outputting it to the conversion smoothing module 35. The conversion smoothing module 35 has the function of reducing sharp value changes (abrupt value changes) when switching the FBA torque from the rack force calculation 22 module to the base SAT21 module, thus avoiding driver confusion.

[0052] According to this embodiment, in addition to the effects of Embodiment 1, a smoother transition from BLC mode to basic SAT mode is possible.

[0053] (Example 3)

[0054] Figure 7 This is a block diagram of the control device of Embodiment 3, another embodiment of the present invention. In this embodiment, the steering-by-wire control device 40 does not have the insensitive band 24 module, which differs from Embodiment 1. The same reference numerals are used for the same components as in Embodiment 1, and descriptions repeated in Embodiment 1 are omitted.

[0055] like Figure 7 As shown, the steer-by-wire control device 30 in this embodiment consists of a basic SAT21 module, a rack force calculation 22 module, a gain K23 module, and a maximum element selection 25 module. Here, the steer-by-wire control device 40 is installed in the ECU. The basic SAT21 module, rack force calculation 22 module, gain K23 module, and maximum element selection 25 module are implemented, for example, using a processor such as a CPU (not shown), a ROM storing various programs, RAM temporarily storing data from the calculation process, or an external storage device. The processor reads and executes the various programs stored in the ROM, and stores the execution result, i.e., the calculation result, in the RAM or external storage device. Furthermore, the steer-by-wire control device 40 is not limited to being installed in the ECU; it can also be installed in other electronic control systems.

[0056] According to this embodiment, it is more efficient than embodiment 1 and can simplify the structure of the steer-by-wire control device 40.

[0057] (Example 4)

[0058] Figure 8 This is a block diagram of the control device of Embodiment 4, another embodiment of the present invention. In this embodiment, the steer-by-wire control device 50 includes a switching module 34a, which inputs the setting of the manual control feedback mode, the output from the maximum element selection module 25, and the output from the rack force calculation module 22 (which converts the calculated rack force into a torque value for FBA), and selects and outputs one of them, which is different from Embodiment 1.

[0059] The same symbols are added to the same constituent elements as in Example 1, and descriptions that are repeated in Example 1 are omitted.

[0060] like Figure 8As shown, the steer-by-wire control device 50 of this embodiment consists of a basic SAT21 module, a rack force calculation 22 module, a gain K23 module, an insensitive zone 24 module, a maximum element selection 25 module, and a switching 34a module. Here, the steer-by-wire control device 20 is installed in the ECU. The basic SAT21 module, rack force calculation 22 module, gain K23 module, insensitive zone 24 module, maximum element selection 25 module, and switching 34a module are implemented, for example, using a processor such as a CPU (not shown), a ROM storing various programs, RAM temporarily storing data from the calculation process, or an external storage device. The processor reads and executes the various programs stored in the ROM, and stores the execution result, i.e., the calculation result, in the RAM or external storage device. Furthermore, the steer-by-wire control device 50 is not limited to being installed in an ECU; it can also be installed in other electronic control systems. Additionally, the switching 34a module can also be implemented in hardware.

[0061] The manual control feedback mode input to the switching 34a module of the control device 50 constituting this embodiment can be set, including whether the driver selects FBA torque feedback or active BLC and always uses rack force calculation feedback.

[0062] The steer-by-wire control device 50 in this embodiment is not limited to... Figure 8 The structure shown. For example, it can also be replaced with... Figure 8 The diagram shows a structure with the insensitive band 24 module and the maximum element selection 25 module, and includes the deviation calculation 31 module, relay 22 module, delay 23 module, switching 34 module, and conversion smoothing 35 module described in Embodiment 2 above. Furthermore, a structure without these modules can also be used. Figure 8 The structure shown is insensitive with 24 modules.

[0063] According to this embodiment, in addition to the effects of embodiments 1 to 3 above, if the driver feels that the comfort of automatically selecting BLC is impaired, comfort can be obtained by switching to manual control feedback mode.

[0064] Alternatively, the structure referred to as a "module" in Embodiments 1 to 4 above can also be referred to as a "section". Specifically, for example, the "basic SAT21 module" can be referred to as the "basic SAT section 21", and the "rack force calculation 22 module" can be referred to as the "rack force calculation section 22". The same applies to other constituent elements.

[0065] Furthermore, the present invention is not limited to the above embodiments, but includes various modifications.

[0066] For example, the above embodiments are described in detail for ease of understanding of the present invention and are not limited to having all the structures described. Furthermore, a portion of the structure of one embodiment can be replaced with the structure of another embodiment, and it is also possible to add structures of other embodiments to the structure of one embodiment.

[0067] Explanation of reference numerals in the attached figures

[0068] 1… Steer-by-wire system

[0069] 11… Steering wheel

[0070] 12…FBA motor (Motor No. 1)

[0071] 13…RWA motor (second motor)

[0072] 14…ball screw

[0073] 15… rack and pinion

[0074] 20, 30, 40, 50… control devices

[0075] 21…Basic SAT

[0076] 22…Rack and pinion force calculation

[0077] 23… Gain K

[0078] 24…Insensitive belt

[0079] 25…Maximum Element Selection

[0080] 31… Deviation Calculation

[0081] 32…relay

[0082] 33…delay

[0083] Switching between 34, 34a...

[0084] 35… Smooth transition.

Claims

1. A steer-by-wire control device comprising a first motor controlling a steering wheel via a feedback actuator and a second motor controlling the steering angle of the wheels via a drive wheel actuator, and capable of bidirectional control of the first motor and the second motor, the steer-by-wire control device being characterized in that it includes: The basic SAT section calculates the analog feedback actuator torque based on the angle of the first motor and the vehicle speed. and The rack force calculation unit calculates the rack force as a reaction force based on the steering angle of the wheel and the actuator of the traveling wheel. The steer-by-wire control device has a first control mode that controls the torque of the analog feedback actuator of the first motor, and a second control mode that controls the first motor based on the reaction force calculated by the rack force calculation unit. The first control mode and the second control mode are switched based on the output of the basic SAT unit and the output of the rack force calculation unit.

2. The steer-by-wire control device as described in claim 1, characterized in that: It includes a maximum element selection unit, which compares the simulated feedback actuator torque obtained by the basic SAT unit with the calculated rack force calculated by the rack force calculation unit, and selects the maximum output as the feedback actuator torque output.

3. The steer-by-wire control device as described in claim 2, characterized in that: It includes an insensitive band section that removes noise contained in the calculated rack force derived by the rack force calculation section.

4. The steer-by-wire control device as described in claim 1, characterized in that, include: The subtraction unit subtracts the calculated rack force calculated by the rack force calculation unit from the analog feedback actuator torque obtained by the basic SAT unit. and The switching unit selects one of the following: the output of the subtraction unit, the calculated rack force derived by the rack force calculation unit, and the analog feedback actuator torque calculated by the basic SAT unit. The output of the switching unit determines the torque of the feedback actuator.

5. The steer-by-wire control device as described in claim 4, characterized in that: It includes a conversion smoothing unit that reduces the sharp value change that occurs when switching the feedback actuator torque from the calculated rack force calculated by the rack force calculation unit to the simulated feedback actuator torque calculated by the basic SAT unit.

6. The steer-by-wire control device as described in claim 1, characterized in that: It includes a switching unit that selects one of the following: the calculated rack force calculated by the rack force calculation unit, the analog feedback actuator torque obtained by the basic SAT unit, and the setting of the manual control feedback mode. The manual control feedback mode is set by using the calculated rack force derived by the rack force calculation unit or the simulated feedback actuator torque obtained by the basic SAT unit as the feedback actuator torque.

7. A steer-by-wire control method comprising a first motor controlling a steering wheel via a feedback actuator and a second motor controlling the steering angle of the wheels via a drive wheel actuator, and capable of bidirectional control of the first motor and the second motor, characterized in that: The basic SAT unit calculates the analog feedback actuator torque based on the angle of the first electric motor and the vehicle speed. The rack force calculation unit calculates the rack force as a reaction force based on the steering angle of the wheel and the actuator of the traveling wheel. Based on the output of the basic SAT unit and the output of the rack force calculation unit, the system switches between a first control mode that controls the torque of the analog feedback actuator of the first motor and a second control mode that controls the first motor based on the reaction force calculated by the rack force calculation unit.

8. The steer-by-wire control method as described in claim 7, characterized in that: The simulated feedback actuator torque calculated by the basic SAT unit is compared with the calculated rack force calculated by the rack force calculation unit, and the output with the larger value is selected as the feedback actuator torque output.

9. The steer-by-wire control method as described in claim 8, characterized in that: The insensitive section removes the noise contained in the calculated rack force derived by the rack force calculation section.

10. The steer-by-wire control method as described in claim 7, characterized in that: The subtraction unit subtracts the calculated rack force calculated by the rack force calculation unit from the analog feedback actuator torque obtained by the basic SAT unit. The switching unit selects one of the following: the output of the subtraction unit, the calculated rack force derived by the rack force calculation unit, and the analog feedback actuator torque calculated by the basic SAT unit. The output of the switching unit determines the torque of the feedback actuator.

11. The steer-by-wire control method as described in claim 10, characterized in that: The conversion smoothing unit reduces the sharp value change that occurs when switching the feedback actuator torque from the calculated rack force calculated by the rack force calculation unit to the simulated feedback actuator torque obtained by the basic SAT unit.

12. The steer-by-wire control method as described in claim 7, characterized in that: The switching unit selects one of the following: the calculated rack force calculated by the rack force calculation unit, the analog feedback actuator torque obtained by the basic SAT unit, and the setting of the manual control feedback mode. The manual control feedback mode is set by using the calculated rack force derived by the rack force calculation unit or the simulated feedback actuator torque obtained by the basic SAT unit as the feedback actuator torque.

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