The endpoint limit device and control method of the steer-by-wire system and its road feel simulator are related to the vehicle.

Abstract

This invention discloses a steer-by-wire system and its end-point limiting device and control method for a road feel simulator, belonging to the technical field of steer-by-wire. It includes a hollow frame with a first through hole and a second through hole on its top and bottom surfaces, respectively; a limiting nut, disposed within the frame with its threaded hole opposite to the first and second through holes, and a vertical limiting groove penetrating its top and bottom surfaces on its outer circumference; a limiting post located within the limiting groove, with both ends fixed to the frame, and the limiting nut slidably connected to the limiting post; two limiting blocks symmetrically disposed on both sides of the limiting nut, each limiting block having a concave isosceles trapezoidal shape on its side near the nut, with the opposite ends of the nut located between the upper and lower inclined surfaces of the two limiting blocks, and the limiting blocks slidably connected to the frame; and a drive assembly for driving the limiting blocks. This design helps improve the limiting effect and reduce costs.

Description

Technical Field

[0001] This invention relates to the technical field of steer-by-wire, specifically to a steer-by-wire system and its end-point limiting device and control method for a road feel simulator, and to a vehicle. Background Technology

[0002] As a future trend in steering technology and an essential component of autonomous driving, steer-by-wire is currently attracting significant investment from OEMs and steering component companies. The endpoint limit devices in steer-by-wire road feel simulators are currently fixed. To achieve endpoint limit at different speeds, the road feel simulator motor needs to provide a reaction torque greater than 30 Nm. This places high demands on the motor's output torque. On one hand, high-performance road feel simulator motors are expensive; on the other hand, the time required for the motor to provide such a large reaction torque is limited, resulting in wasted torque. During use, when the driver's operating force is excessive, the endpoint limit achieved through the road feel simulator motor is prone to failure, resulting in poor limiting performance. Summary of the Invention

[0003] To address at least one aspect of the above-mentioned problems, the present invention provides a steer-by-wire system and its road feel simulator, an endpoint limiting device and control method, and a vehicle.

[0004] In a first aspect, this application provides an end-point limiting device for a steer-by-wire road feel simulator, including a fixed frame, a limiting component, a drive component, and a control component; the fixed frame is a hollow structure, including a top surface and a bottom surface parallel to and opposite to the XY plane, and two side surfaces parallel to and opposite to the YZ plane, with both side surfaces disposed between the top and bottom surfaces; a first through hole and a second through hole are respectively opened at opposite locations in the middle regions of the top and bottom surfaces of the fixed frame; a bearing is fixedly connected in the second through hole; the limiting component is disposed within the fixed frame, and includes a limiting nut, a limiting post, and two limiting blocks; the limiting... The nut is set inside the fixed frame. The threaded hole of the limit nut is aligned with the first through hole and the second through hole. The threaded hole of the limit nut matches the steering shaft of the steer-by-wire system, so that when the steering shaft of the steer-by-wire system passes through the first through hole and the threaded hole of the limit nut in sequence and connects with the bearing, the steering shaft is threadedly connected to the limit nut. At least two limit grooves extending along the Z direction and penetrating its top and bottom surfaces are formed on the outer circumferential surface of the limit nut. The two limit grooves are aligned with each other. At least two limit posts are provided. The size of the limit posts matches the size of the limit grooves. The limit posts extend along the Z direction, and the two limit posts are located in the two limit grooves respectively. The top of the limit posts... The bottom and top ends are fixedly connected to the top and bottom surfaces of the fixed frame, respectively. The outer circumferential surface of the limiting nut is slidably connected to the limiting post along the Z direction through the limiting groove. Two limiting blocks are set inside the fixed frame and symmetrically arranged on both sides of the limiting nut along the X direction, respectively located between the limiting nut and the sides of the two fixed frames. The side of the limiting block near the limiting nut is a concave isosceles trapezoidal shape. The side of the limiting block near the limiting nut includes an upper inclined surface, a middle surface, and a lower inclined surface. The middle surface is parallel to the YZ plane. The top and bottom ends of the middle surface are connected to the bottom end of the upper inclined surface and the top end of the lower inclined surface, respectively. The angle between the upper inclined surface and the middle surface and the angle between the lower inclined surface and the middle surface are... The included angles of the intersecting surfaces are all obtuse angles; the two opposite ends of the limiting nut along the X direction are located between the upper and lower inclined surfaces of the two limiting blocks, respectively; the top and bottom surfaces of the limiting blocks are slidably connected to the top and bottom surfaces of the fixing frame along the X direction, approaching or moving away from the limiting nut; two sets of drive components are provided, respectively located on the two sides of the fixing frame and between the two limiting blocks, for driving the two limiting blocks to approach or move away from the limiting nut along the X direction; the output end of the control unit is connected to the two sets of drive components, and the input end of the control unit is used to connect to the vehicle's CAN line, for controlling the operation of the drive components according to the vehicle speed signal on the vehicle's CAN line.

[0005] Preferably, the connection between the top surface of the limiting nut and the outer peripheral surface located between the upper and lower inclined surfaces of the limiting block is a first inclined surface parallel to the upper inclined surface, and the connection between the bottom surface of the limiting nut and the outer peripheral surface located between the upper and lower inclined surfaces of the limiting block is a second inclined surface parallel to the lower inclined surface.

[0006] Preferably, the drive assembly includes a motor, a lead screw, and a nut; the motor is fixedly connected to the side of the fixed frame; the nut is a ball nut, and the nut is coaxially fixedly connected to the rotor of the motor; the lead screw is a ball screw, which extends along the X direction, passes through the nut, and cooperates with the nut; the first end of the lead screw is fixedly connected to a limit block.

[0007] Preferably, the control unit includes two controllers, which are respectively fixedly connected to the motors in the two sets of drive assemblies or both are fixedly connected to the mounting bracket. The two controllers are electrically connected to the motors in the two sets of drive assemblies to control the operation of the motors. Both controllers are connected to the vehicle's CAN bus.

[0008] Preferably, shock-absorbing pads are fixedly laid on the sides of both limiting blocks near the limiting nuts.

[0009] Preferably, sliders are fixedly connected to both the top and bottom surfaces of the limiting block; a sliding groove extending along the X direction is provided on both sides of the first through hole on the top surface of the fixing frame, and a sliding groove extending along the X direction is provided on both sides of the second through hole on the bottom surface of the fixing frame; the slider on the top surface of the limiting block is located in the sliding groove on the top surface of the fixing frame, and the slider on the bottom surface of the limiting block is located in the sliding groove on the bottom surface of the fixing frame, and the slider and the sliding groove are slidably connected along the X direction.

[0010] Preferably, the fixing frame is a hollow rectangular tube structure formed by its top surface, bottom surface and two side surfaces. The top ends of the two side surfaces of the fixing frame are fixedly connected to the two ends of the top surface of the fixing frame along the X direction, and the bottom ends of the two side surfaces of the fixing frame are fixedly connected to the two ends of the bottom surface of the fixing frame along the X direction.

[0011] Secondly, this application provides a control method for an endpoint limit device of a steer-by-wire road feel simulator, used in the control component of any of the aforementioned endpoint limit devices for a steer-by-wire road feel simulator, comprising the following steps: receiving current vehicle speed information from the vehicle's CAN bus; obtaining the current ideal transmission ratio based on the current vehicle speed information and a preset vehicle speed-ideal transmission ratio curve; calculating the current ideal position of the limit block based on the ideal transmission ratio, the design parameters of the current vehicle steer-by-wire system, and the design parameters of the endpoint limit device of the current vehicle steer-by-wire system road feel simulator; and sending the current ideal position of the limit block to the drive component, causing the drive component to drive the limit block to the current ideal position.

[0012] Preferably, when the limiting nut has a first inclined surface and a second inclined surface, the formula for calculating the current ideal position of the limiting block is:

[0013] ,

[0014] Where d represents the current ideal position of the limit block, and the position of the limit block is set to 0 at the minimum distance from the upper inclined surface to the lower inclined surface of the limit nut; i represents the ideal transmission ratio; α represents the maximum turning angle of the inner wheel of the current vehicle, β represents the maximum turning angle of the outer wheel of the current vehicle, and α and β are defined according to the vehicle type; k represents the thread pitch of the thread at the connection between the limit nut and the steering shaft. The angle between the upper inclined face and the middle face in the endpoint limit device of the road feel simulator.

[0015] Thirdly, this application provides a steer-by-wire system, including an endpoint limiting device for a steer-by-wire road feel simulator as described above, wherein the steering shaft passes through the first through hole and the threaded hole of the limiting nut in sequence and is connected to the bearing, and the steering shaft is threadedly connected to the limiting nut; the fixing bracket is fixedly connected to the deceleration mechanism of the steer-by-wire system.

[0016] Fourthly, this application provides a vehicle including the aforementioned steer-by-wire system, wherein the control unit is connected to the vehicle's CAN bus.

[0017] The steer-by-wire system, its road feel simulator, endpoint limiting device, and control method of the present invention, along with the vehicle, have the following beneficial effects:

[0018] This application designs a mechanical end-point limiting device that changes its limit according to vehicle speed. Specifically, it designs limiting blocks with concave isosceles trapezoidal shapes on both sides of the limiting nut. When the steering shaft of the linear steering system drives the limiting nut upwards or downwards until the opposite ends of the limiting nut abut against the upper or lower inclined surfaces of the two limiting blocks, restricting the movement of the limiting nut and thus limiting the rotation of the steering shaft, achieving the end-point limiting function. The control components and drive assembly dynamically adjust the position of the limiting blocks according to vehicle speed, i.e., adjusting the distance between the limiting blocks and the limiting nut in the x-direction, thereby adjusting the movable distance of the limiting nut in the z-direction between the upper and lower inclined surfaces of the limiting blocks. This allows the end-point limit to change with vehicle speed, reducing the requirements for the road feel simulation motor, lowering the component cost of the steer-by-wire road feel simulator, and improving the limiting effect. Attached Figure Description

[0019] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0020] Figure 1A schematic diagram of the end-point limiting device for a steer-by-wire road feel simulator according to an embodiment of the present invention is shown;

[0021] Figure 2 An exploded view of an end-point limiting device for a road feel simulator with steer-by-wire according to an embodiment of the present invention is shown;

[0022] Figure 3 A schematic diagram illustrating the operating principle of the end-point limiting device for a steer-by-wire road feel simulator according to an embodiment of the present invention is shown.

[0023] Figure 4 A graph showing the preset vehicle speed versus the ideal transmission ratio is presented for the control method of the endpoint limit device for a steer-by-wire road feel simulator according to an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Fixing bracket; 11. First through hole; 12. Second through hole; 13. Slide groove; 2. Bearing; 3. Limiting nut; 31. Threaded hole; 32. Limiting groove; 33. First inclined surface; 34. Second inclined surface; 4. Limiting post; 5. Limiting block; 51. Upper inclined surface; 52. Middle surface; 53. Lower inclined surface; 54. Sliding block; 55. Shock absorber; 61. Motor; 611. Fixing bolt; 62. Lead screw; 71. First buckle; 72. Second buckle; 73. Third buckle; 8. Controller; 9. Steering shaft. Detailed Implementation

[0026] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0027] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0028] To at least partially address one or more of the aforementioned problems and other potential issues, embodiments of this disclosure provide an end-point limiting device for a steer-by-wire road feel simulator, such as... Figures 1 to 3 As shown, it includes a fixed frame 1, a limiting assembly, a driving assembly, and a control component.

[0029] like Figure 2 As shown, the fixing frame 1 is a hollow structure. The fixing frame 1 includes a top surface and a bottom surface parallel to the XY plane and arranged opposite each other, and two side surfaces parallel to the YZ plane and arranged opposite each other. Both side surfaces of the fixing frame 1 are located between its top surface and bottom surface. The X direction is the length direction of the fixing frame 1, the Y direction is the width direction of the fixing frame 1, and the Z direction is the height direction of the fixing frame 1. Specifically, the fixing frame 1 is a hollow closed structure or a hollow structure with openings at both ends along the Y direction. The cross-section of the fixing frame 1 along the XZ plane is a rectangle, octagon, or other polygon. Alternatively, the fixing frame 1 has two side surfaces arranged parallel to each other, and the two side surfaces are perpendicular to its top surface and bottom surface, respectively. The connection between its top surface and side surface and its bottom surface and side surface is an arc transition structure. Preferably, the fixing frame 1 is a hollow rectangular tube structure enclosed by its top surface, bottom surface, and two side surfaces. The top ends of the two side surfaces of the fixing frame 1 are fixedly connected to the two ends of the top surface of the fixing frame 1 along the X direction, respectively. The bottom ends of the two side surfaces of the fixing frame 1 are fixedly connected to the two ends of the bottom surface of the fixing frame 1 along the X direction, respectively. A first through hole 11 and a second through hole 12 are respectively provided at the opposite positions of the middle area of ​​the top surface and the middle area of ​​the bottom surface of the fixing frame 1; a bearing 2 is fixedly connected in the second through hole 12. Specifically, the bearing 2 is preferably a needle roller bearing 2, and the bearing 2 is pressed into the second through hole 12 by interference fit.

[0030] The limiting component is set inside the fixed frame 1. The limiting component includes a limiting nut 3, a limiting post 4, and two limiting blocks 5. The limiting nut 3 is set inside the fixed frame 1. The axial direction of the limiting nut 3 is Z. The dimension of the limiting nut 3 along the Z direction is smaller than the distance between the top and bottom surfaces of the fixed frame 1. The threaded hole 31 of the limiting nut 3 is opposite to the first through hole 11 and the second through hole 12. The threaded hole 31 of the limiting nut 3 matches the steering shaft 9 of the steer-by-wire system. When the steering shaft 9 of the steer-by-wire system passes through the first through hole 11 and the threaded hole 31 of the limiting nut 3 and connects to the bearing 2, the steering shaft 9 is threadedly connected to the limiting nut 3. Preferably, a first buckle 71 is connected to the area of ​​the steering shaft 9 that extends out of the bearing 2 to prevent the steering shaft 9 from coming out. At least two limiting grooves 32 extending along the Z direction and passing through its top and bottom surfaces are opened on the outer peripheral surface of the limiting nut 3. The two limiting grooves 32 are opposite to each other.

[0031] At least two limiting posts 4 are provided. The size of the limiting posts 4 matches the size of the limiting grooves 32. The limiting posts 4 extend along the Z direction. The two limiting posts 4 are located in the two limiting grooves 32 respectively. The top and bottom ends of the limiting posts 4 are fixedly connected to the top and bottom surfaces of the fixing frame 1 respectively through the second buckle 72. The outer circumferential surface of the limiting nut 3 is slidably connected to the limiting posts 4 along the Z direction through the limiting grooves 32.

[0032] Both limiting blocks 5 are set inside the fixing frame 1 and symmetrically arranged on both sides of the limiting nut 3 along the X direction, respectively located between the limiting nut 3 and the sides of the two fixing frames 1; the cross-section of the side of the limiting block 5 near the limiting nut 3 along the XZ plane is a concave isosceles trapezoidal shape. The side of the limiting block 5 near the limiting nut 3 includes an upper inclined surface 51, a middle surface 52, and a lower inclined surface 53. The middle surface 52 is parallel to the YZ plane. The top and bottom ends of the middle surface 52 are connected to the bottom end of the upper inclined surface 51 and the top end of the lower inclined surface 53, respectively. The angles between the upper inclined surface 51 and the middle surface 52, and between the lower inclined surface 53 and the middle surface 52, are both obtuse angles. Figure 3 As shown in γ, preferably, the angle between the upper inclined surface 51 and the middle surface 52 and the angle between the lower inclined surface 53 and the middle surface 52 are equal; in a preferred embodiment, shock-absorbing pads 55 are fixedly laid on the sides of the two limiting blocks 5 near the limiting nut 3. The two opposite ends of the limiting nut 3 along the X direction are respectively located between the upper inclined part 51 and the lower inclined part 53 of the two limiting blocks 5; the top surface and bottom surface of the limiting block 5 are slidably connected to the top surface and bottom surface of the fixing frame 1 along the X direction, close to or away from the limiting nut 3. Specifically, sliders 54 are fixedly connected to the top surface and bottom surface of the limiting block 5; the top surface of the fixing frame 1 has grooves 13 extending along the X direction on both sides of the first through hole 11, and the bottom surface of the fixing frame 1 has grooves 13 extending along the X direction on both sides of the second through hole 12; the sliders 54 on the top surface of the limiting block 5 are located in the grooves 13 on the top surface of the fixing frame 1, and the sliders 54 on the bottom surface of the limiting block 5 are located in the grooves 13 on the bottom surface of the fixing frame 1. The sliders 54 and the grooves 13 are slidably connected along the X direction.

[0033] In a preferred embodiment, the connection between the top surface of the limiting nut 3 located between the upper inclined portion 51 and the lower inclined portion 53 of the limiting block 5 and the outer peripheral surface is a first inclined surface 33 parallel to the upper inclined portion 51, and the connection between the bottom surface of the limiting nut 3 located between the upper inclined portion 51 and the lower inclined portion 53 of the limiting block 5 and the outer peripheral surface is a second inclined surface 34 parallel to the lower inclined portion 53.

[0034] During the rotation of the steering shaft 9, the limiting nut 3 is driven to move upward or downward along the Z direction. When the two ends of the limiting nut 3 abut against the upper inclined part 51 or the lower inclined part 53 of the two limiting blocks 5, the limiting nut 3 stops moving upward or downward, restricting the axial shaft from continuing to rotate in the same direction, thus achieving the end-point limiting function.

[0035] Two sets of drive components are provided, which are respectively set between the two sides of the fixed frame 1 and the two limit blocks 5. They are used to drive the two limit blocks 5 to move closer to or further away from the limit nut 3 along the X direction, thereby adjusting the movable distance of the limit nut 3 in the Z direction between the upper inclined part 51 and the lower inclined part 53 of the limit block 5, so as to realize the adjustment of the end limit. Specifically, the drive assembly includes a motor 61, a lead screw 62, and a nut; the motor 61 is fixedly connected to the side of the mounting bracket 1 by a fixing bolt 611; the nut is a ball screw nut, which is coaxially fixedly connected to the rotor of the motor 61; the lead screw 62 is a ball screw 62, which extends along the X direction, passes through the nut, and cooperates with the nut; the first end of the lead screw 62 is fixedly connected to the limiting block 5 through the shoulder of the lead screw 62 and the third buckle 73, and the second end of the lead screw 62 passes through the side of the mounting bracket 1. The rotor of the motor 61 drives the nut to rotate, and the nut drives the lead screw 62 to make a linear movement along the X direction, thereby driving the limiting block 5 to move closer to or away from the limiting nut 3 along the X direction.

[0036] In the design of the device of this application, the lead screw has a stroke of 62. The calculation process is as follows:

[0037] because ,and ,but ,in, Represents the ideal transmission ratio. Represents the total steering wheel angle. This represents the maximum steering angle of the inner wheel of the vehicle at present. This represents the maximum steering angle of the outer wheel of the vehicle at present. and Defined according to vehicle type. This represents the total number of turns of the steering wheel.

[0038] like Figure 4 As shown, based on the curve relationship between vehicle speed and ideal transmission ratio defined by the vehicle model, it can be known that... and Therefore, it can be known and .

[0039] because ,in This represents the distance the limiting nut 3 travels from the upper inclined surface 51 to the lower inclined surface 53 of the limiting block 5. This represents the thread pitch at the connection between the limit nut 3 and the steering shaft 9. Therefore, , , This represents the maximum distance that the limiting nut 3 can move from the upper inclined surface 51 to the lower inclined surface 53 of the limiting block 5. This represents the minimum distance that the limiting nut 3 travels from the upper inclined surface 51 to the lower inclined surface 53 of the limiting block 5.

[0040] According to geometric relations, we know Then the lead screw has a stroke of 62. ,in The angle between the upper inclined surface 51 and the middle surface 52 in the end-point limiting device of the road feel simulator. According to Design the length of each groove.

[0041] The output of the control unit is connected to two sets of drive components, and the input of the control unit is connected to the vehicle's CAN bus. It controls the operation of the drive components based on the vehicle speed signal on the CAN bus, thereby adjusting the endpoint limit according to the vehicle speed. Specifically, the control unit includes two controllers 8. Each controller 8 is fixedly connected to a motor 61 in one of the two sets of drive components, or both are fixedly connected to a mounting bracket 1. The two controllers 8 are electrically connected to the motors 61 in the two sets of drive components to control the operation of the motors 61. Both controllers 8 are connected to the vehicle's CAN bus to receive the vehicle speed signal from the CAN bus.

[0042] This application also provides a control method for an end-point limiting device in a steer-by-wire road feel simulator, used in the control component of any of the aforementioned end-point limiting devices for a steer-by-wire road feel simulator, comprising the following steps: receiving current vehicle speed information from the vehicle's CAN bus; obtaining the current ideal transmission ratio based on the current vehicle speed information and a preset vehicle speed-ideal transmission ratio curve, specifically, the preset vehicle speed-ideal transmission ratio curve is defined according to the vehicle model, such as... Figure 4 As shown, the horizontal axis represents vehicle speed, and the vertical axis represents the ideal transmission ratio. Based on the ideal transmission ratio, the design parameters of the current vehicle steer-by-wire system, and the design parameters of the endpoint limit device of the current vehicle steer-by-wire system road feel simulator, the current ideal position of the limit block 5 is calculated. The current ideal position of the limit block 5 is sent to the drive component, so that the drive component drives the limit block 5 to reach the current ideal position.

[0043] In a preferred embodiment, when the limiting nut 3 has a first inclined surface 33 and a second inclined surface 34, the formula for calculating the current ideal position of the limiting block 5 is as follows:

[0044] ,

[0045] Where d represents the current ideal position of the limit block 5, and the position of the limit block 5 is set to 0 at the minimum distance from the upper inclined part 51 to the lower inclined part 53 of the limit nut 3; i represents the ideal transmission ratio; α represents the maximum turning angle of the inner wheel of the current vehicle, β represents the maximum turning angle of the outer wheel of the current vehicle, and α and β are defined according to the vehicle type; k represents the thread pitch of the thread at the connection between the limit nut 3 and the steering shaft 9. The angle between the upper inclined surface 51 and the middle surface 52 in the end-point limiting device of the road feel simulator, such as Figure 3 As shown.

[0046] This application also provides a steer-by-wire system, including an endpoint limiting device for a steer-by-wire road feel simulator as described above. The steering shaft 9 passes through the first through hole 11 and the threaded hole 31 of the limiting nut 3 in sequence and is connected to the bearing 2. The steering shaft 9 is threadedly connected to the limiting nut 3. Preferably, the steering shaft 9 passes through the bearing 2, and a first buckle 71 is connected at the area where the steering shaft 9 extends out of the bearing 2 to prevent the steering shaft 9 from coming out. The fixing frame 1 is fixedly connected to the deceleration mechanism of the steer-by-wire system.

[0047] This application also provides a vehicle including the above-described steer-by-wire system, wherein the control unit is connected to the vehicle CAN bus, specifically, both controllers 8 are connected to the vehicle CAN bus.

[0048] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand this document.

Claims

1. An end-point limiting device for a steer-by-wire road feel simulator, characterized in that: The system includes a fixed frame, a limiting assembly, a drive assembly, and control components. The fixed frame is a hollow structure with a first through hole and a second through hole at opposite locations on its top and bottom surfaces, respectively. A bearing is fixedly connected within the second through hole. The limiting assembly is located within the fixed frame and includes a limiting nut, a limiting post, and two limiting blocks. The threaded hole of the limiting nut is aligned with the first and second through holes and matches the steering shaft of the steer-by-wire system. A limiting groove extending along the Z-direction and penetrating the top and bottom surfaces of the limiting nut is formed on its outer circumference. The limiting post is located within the limiting groove, with its two ends fixedly connected to the top and bottom surfaces of the fixed frame, respectively. The limiting nut is slidably connected to the limiting post along the Z-direction via the limiting groove. Two limiting blocks are symmetrically arranged within the limiting nut. The limiting nuts are located on both sides along the X-direction; the sides of the limiting blocks near the limiting nuts are concave isosceles trapezoidal shapes, including an upper inclined surface, a middle surface, and a lower inclined surface. The middle surface is parallel to the YZ plane, and the angles between the upper inclined surface and the middle surface, and between the lower inclined surface and the middle surface, are both obtuse angles; the two ends of the limiting nuts along the X-direction are located between the upper and lower inclined surfaces of the two limiting blocks, respectively; the top and bottom surfaces of the limiting blocks are slidably connected to the top and bottom surfaces of the fixing frame along the direction of approaching or moving away from the limiting nuts, respectively; the drive assembly is used to drive the two limiting blocks to approach or move away from the limiting nuts along the X-direction, respectively; the control unit is connected to the drive assembly and the vehicle CAN line, and is used to control the operation of the drive assembly according to the vehicle speed signal of the vehicle CAN line.

2. The endpoint limiting device for a steer-by-wire road feel simulator according to claim 1, characterized in that: The connection between the top surface and the outer peripheral surface of the limiting nut located between the upper and lower inclined surfaces of the limiting block is a first inclined surface parallel to the upper inclined surface, and the connection between the bottom surface and the outer peripheral surface of the limiting nut located between the upper and lower inclined surfaces of the limiting block is a second inclined surface parallel to the lower inclined surface.

3. The endpoint limiting device for a steer-by-wire road feel simulator according to claim 1, characterized in that: The drive assembly includes a motor, a lead screw, and a nut; the motor is fixedly connected to the side of the fixed frame; the nut is a ball nut, and the nut is coaxially and fixedly connected to the rotor of the motor; the lead screw is a ball screw, which extends along the X direction, passes through the nut, and cooperates with the nut; the first end of the lead screw is fixedly connected to a limit block.

4. The endpoint limiting device for a steer-by-wire road feel simulator according to claim 1, characterized in that: Both of the aforementioned limiting blocks have shock-absorbing pads fixedly laid on their sides near the limiting nuts.

5. The endpoint limiting device for a steer-by-wire road feel simulator according to claim 1, characterized in that: The limiting block has sliders fixedly connected to both its top and bottom surfaces; the top surface of the fixing frame has sliding grooves extending along the X direction on both sides of the first through hole, and the bottom surface of the fixing frame has sliding grooves extending along the X direction on both sides of the second through hole; the slider on the top surface of the limiting block is located in the sliding groove on the top surface of the fixing frame, and the slider on the bottom surface of the limiting block is located in the sliding groove on the bottom surface of the fixing frame, and the slider and the sliding groove are slidably connected along the X direction.

6. The endpoint limiting device for a steer-by-wire road feel simulator according to claim 1, characterized in that: The fixing frame is a hollow rectangular tube structure formed by its top surface, bottom surface and two side surfaces. The top ends of the two side surfaces of the fixing frame are fixedly connected to the two ends of the top surface of the fixing frame along the X direction, and the bottom ends of the two side surfaces of the fixing frame are fixedly connected to the two ends of the bottom surface of the fixing frame along the X direction.

7. A control method for an end-point limiting device in a steer-by-wire road feel simulator, used in the control element of the end-point limiting device for a steer-by-wire road feel simulator as described in any one of claims 1 to 6, characterized in that: Includes the following steps: Receive current vehicle speed information from the vehicle's CAN bus; Based on the current vehicle speed information, and using the preset vehicle speed and ideal transmission ratio curve, the current ideal transmission ratio is obtained. Based on the ideal transmission ratio, the design parameters of the current vehicle steer-by-wire system, and the design parameters of the endpoint limit device of the current vehicle steer-by-wire system road feel simulator, the current ideal position of the limit block is calculated. Send the current ideal position of the limit block to the driving component, so that the driving component drives the limit block to the current ideal position.

8. The control method for an end-point limit device in a steer-by-wire road feel simulator according to claim 7, characterized in that: When the limiting nut has a first inclined surface and a second inclined surface, the formula for calculating the current ideal position of the limiting block is: ， Where d represents the current ideal position of the limit block, and the position of the limit block is set to 0 at the minimum distance from the upper inclined surface to the lower inclined surface of the limit nut; i represents the ideal transmission ratio; α represents the maximum turning angle of the inner wheel of the current vehicle, β represents the maximum turning angle of the outer wheel of the current vehicle, and α and β are defined according to the vehicle type; k represents the thread pitch of the thread at the connection between the limit nut and the steering shaft. The angle between the upper inclined face and the middle face in the endpoint limit device of the road feel simulator.

9. A steer-by-wire system, characterized in that: The device includes an end-point limiting device for a steer-by-wire road feel simulator as described in any one of claims 1 to 6, wherein the steering shaft passes through the first through hole and the threaded hole of the limiting nut in sequence and is connected to the bearing, and the steering shaft is threadedly connected to the limiting nut; the fixing frame is fixedly connected to the deceleration mechanism of the steer-by-wire system.

10. A vehicle, characterized in that: The system includes a steer-by-wire system as described in claim 9, wherein the control unit is connected to the vehicle's CAN bus.

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