Lower steering assembly, steering system and control method of steering system

Abstract

The invention discloses a lower steering assembly, a steering system and a control method of the steering system. The lower steering assembly comprises a rack which is in transmission connection with wheels, the rack can transversely move relative to a vehicle, an adapter is arranged on the peripheral face of the rack, and the adapter is provided with a first calibration position; the first detection piece is provided with a second calibration position, and the first detection piece comprises a magnet exciting coil and a plurality of induction coils; the processor is in signal connection with the first detection piece; when the rack moves, the excitation coil interacts with the adapter to excite a magnetic field signal, and the induction coil can receive the magnetic field signal and form a sinusoidal waveform signal pulse.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a lower steering assembly, a steering system and a control method of the steering system. Background Art

[0002] The upper and lower steering of the traditional steering system are connected through a mechanical transmission structure, and the rack movement distance can be converted from the angle output by the steering wheel angle sensor. In contrast, the upper and lower steering of the wire control system do not have a mechanical connection structure and are connected by signals instead. Because the lower steering needs to detect the rack displacement for feedback control, etc. Therefore, in the wire control system, the lower steering needs to be equipped with a sensor to detect the displacement of the rack.

[0003] Currently, in the wire control steering system, the steering wheel angle sensor used in the traditional steering system is still used to detect the rack displacement. However, this detection method has a complex structure. Summary of the invention

[0004] An object of the present invention is to provide a new technical solution for a lower steering assembly, a steering system and a control method for the steering system, by improving the structure of the lower steering assembly, so that the displacement of the rack can be detected in a simpler form.

[0005] On the one hand, a lower steering assembly is provided, including a rack connected to a wheel driving mechanism, the rack being capable of moving laterally of the vehicle, an adapter being provided on the outer peripheral surface of the rack, the adapter being provided with a first calibration position; a first detection member being provided with a second calibration position, the first detection member comprising an excitation coil and an induction coil; a processor being signal-connected to the first detection member; when the rack moves horizontally, the excitation coil interacts with the adapter to excite a magnetic field signal, the induction coil being capable of inducing the magnetic field signal and forming a signal pulse of a sinusoidal waveform, the processor being used to receive the sinusoidal waveform, thereby determining a moving distance of the first calibration position relative to the second calibration position.

[0006] During the movement of the rack, the first calibrated position moves relative to the second calibrated position, the excitation coil interacts with the adapter to excite a magnetic field signal, and the induction coil can receive the magnetic field signal and form a sinusoidal waveform signal pulse. The processor collects the pulse signal and forms a sinusoidal envelope through calculation. Multiple induction coils can form multiple sine waves, and the phase difference of the multiple sine waves is a fixed value, so that the displacement of the first calibrated position of the rack 2 relative to the second calibrated position can be determined.

[0007] By adopting the method described in the present invention, by providing an adapter on the rack and providing a first detection member on the support structure, when the rack moves in the horizontal direction of the vehicle, the first detection member and the adapter form a matching method, so that the displacement of the first calibration position relative to the second calibration position can be determined, thereby determining the displacement of the rack. In this way, in the process of detecting the displacement of the rack, there is no need to convert the horizontal movement of the rack into an angle before detecting it, but the horizontal displacement of the rack is directly detected by forming electromagnetic induction between the first detection member and the adapter provided on the rack, thereby effectively reducing the number of parts of the lower steering assembly and simplifying the structure of the lower steering assembly.

[0008] In a second aspect, a steering system including the above-mentioned lower steering assembly is provided.

[0009] In a third aspect, a control method based on the steering system is provided.

[0010] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0012] Figure 1 is a schematic structural diagram of a lower steering assembly in an embodiment of the present invention;

[0013] Figure 2 yes Figure 1 A schematic structural diagram of a first detection member and a rack of a lower steering assembly;

[0014] Figure 3 is a radial cross-sectional view of a rack in an embodiment of the present invention;

[0015] Figure 4 4 is a flow chart of a steering system control method in an embodiment of the present invention.

[0016] Description of reference numerals:

[0017] 1. Support structure;

[0018] 2. rack; 21. adapter; 211. connecting part; 212. sensing sheet;

[0019] 3. Steering motor; 31. Angle sensor;

[0020] 4. first detection member; 41. substrate; 42. excitation coil; 43. induction coil;

[0021] 5. Steering rod;

[0022] 6. Wheels. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] According to the technical solution of the present invention, a lower steering assembly in a wire-controlled steering system is provided. The steering system includes a rack 2, a steering motor 3, a processor and a first detection member 4. The rack 2 is arranged on a supporting structure 1.

[0025] like Figure 1 and Figure 2 As shown, the steering motor 3 is connected to the rack 2 provided on the support structure 1. The steering motor 3 can sense the rotation direction and angle of the steering wheel and output torque to drive the rack 2 to move left or right along the support structure 1 in the horizontal direction of the vehicle. The rack 2 is connected to at least one wheel 6 of the vehicle through a steering tie rod 5. When the rack 2 moves left or right, the direction of the wheel 6 can be changed.

[0026] In order to detect the displacement of the rack 2 , an adapter 21 capable of cooperating with the first detection member 4 is provided on the outer peripheral surface of the rack 2 , and the adapter 21 is provided with a first calibration position.

[0027] For example, Figure 3 As shown, the adapter 21 extends from the main body of the rack 2 and is T-shaped. The T-shaped adapter 21 includes a thin sheet-shaped sensing sheet 212, which extends in the horizontal direction. The sensing sheet 212 is calibrated as a first calibration position. The adapter 21 also includes a connecting portion 211, which is connected between the main body of the rack 2 and the sensing sheet 212, and the connecting portion 211 is arranged perpendicular to the sensing sheet 212.

[0028] It is understandable that the specific structure of the connecting portion 211 is not limited here, as long as it can support the sensing sheet portion 212 .

[0029] The first detection member 4 is provided with a second calibration position. The calibration method of the first calibration position and the second calibration position is:

[0030] When the wheel 6 is in the forward direction, that is, the vehicle is in a straight-ahead state, the second calibration position is calibrated on the first detection member 4, and the second calibration position can be selected by the technicians in this field. At this time, the adapter 21 of the rack 2 corresponding to the second calibration position is calibrated as the first calibration position. Of course, it is also possible to calibrate the first calibration position and the second calibration position when the wheel 6 has a set rotation angle; it is also possible to calibrate the first calibration position first, and then calibrate the corresponding second calibration position.

[0031] like Figure 2 As shown, the first detection member 4 includes a substrate 41, which is fixed to the support structure 1 and arranged opposite to the adapter 21. For example, the substrate 41 of the first detection member 4 is a PCB board, and the length of the PCB board is set so that the range of the first detection member 4 is a complete sinusoidal signal. Among them, the range of the first detection member 4 refers to: the range of left and right movement of the first calibration position that can be measured by the first detection member 4. Specifically, in the technical solution of the present invention, the envelope of the voltage difference collected during the movement from the head end to the end of the first calibration position in the complete range of the first detection member 4 is a sine wave. The horizontal coordinate of the sine wave corresponds to the displacement. Of course, the displacement value can also be converted into the corresponding angle of wheel rotation.

[0032] An excitation coil 42 and an induction coil 43 are constructed on the substrate 41. The excitation coil 42 is in a closed rectangular shape, and the induction coil 43 is arranged in an inner area surrounded by the excitation coil 42. The induction coil 43 is arranged in a plurality of rhombus shapes.

[0033] The excitation coil 42 and the induction coil 43 are arranged along the axial direction of the rack 2 and at least partially cover the moving range of the adapter 21 .

[0034] In order to verify the displacement of the first calibration position, the first detection member 4 includes a plurality of induction coils 43 , and the plurality of induction coils 43 are cross-staggered.

[0035] For example, during the movement of the rack 2, the first calibration position moves relative to the second calibration position, the excitation coil 42 interacts with the sensing sheet 212 to excite a magnetic field signal, and the induction coil 43 can receive the magnetic field signal and form a sinusoidal waveform signal pulse. The processor collects the pulse signal and forms a sinusoidal envelope through calculation. Figure 2 The first detection member 4 includes a first induction coil U1, a second induction coil U2 and a third induction coil U3. By detecting the sine waves sensed by the three induction coils 43, at least two phase differences can be formed to determine the displacement of the first detection position relative to the second detection position. The phase difference of the multiple sine waves is a fixed value. If a non-fixed value occurs, an error is reported.

[0036] Of course, the number of the induction coils 43 may be 4 or 5. There is no limitation on the specific number of the induction coils 43 as long as a phase difference can be formed.

[0037] Optionally, in order to increase the strength of the signal, a plurality of adapters 21 are provided, and the plurality of adapters 21 are sequentially spaced apart along the axial direction of the rack 2 .

[0038] In one example, the adapter 21 and the rack 2 are an integral structure. Of course, the rack 2 can also be connected to the adapter 21 by bonding, welding, etc. However, it is obvious that the rack 2 and the adapter 21 are an integral structure, which has higher strength and fewer parts. The adapter 21 is separately connected to the rack 2, and the processing is relatively simple.

[0039] In some embodiments of the present invention, a wire-controlled steering system is also provided, which includes an upper steering assembly and the aforementioned lower steering assembly, the upper steering assembly and the lower steering assembly are signal-connected. The upper steering assembly includes a steering wheel and a second detection member, and the second detection member is used to detect the displacement of the steering wheel.

[0040] The steering motor 3 in the lower steering assembly is also equipped with an angle sensor 31 for detecting the rotation angle of the output end of the steering motor 3. The angle sensor 31 is, for example, a resolver, a Hall sensor, a magnetoresistive sensor, and the like.

[0041] The angle sensor 31 is connected to the processor signal. After the angle sensor 31 detects the rotation angle of the steering motor 3, the processor converts the rotation angle of the steering motor 3 into the number of rotations of the steering motor.

[0042] In the above embodiment, based on the above steering system, the present invention also provides a control method of the steering system.

[0043] like Figure 4 As shown, the method includes:

[0044] S1. Detection of the displacement of the first calibrated position of the rack 2;

[0045] S2. Determine whether the first calibration position is moved outside the range of the first detection member;

[0046] S3. When the judgment result is yes, the total displacement of the first calibrated position is determined by the rotation angle of the steering motor 3;

[0047] The total displacement includes the sum of the displacement of the first calibrated position within the measuring range of the first detection member and the displacement after exceeding the measuring range.

[0048] There are many ways to determine whether the first calibration position moves outside the range of the first detection member 4. For example, the processor determines by a sudden change in the induced voltage of the first detection member 4, or by calculating in advance the rotation angle of the steering motor 3 when the first calibration position is within the range, and then determining by detecting the actual rotation angle of the steering motor 3.

[0049] In a specific embodiment, the processor receives the sinusoidal waveform emitted by the induction coil to calculate the phase difference of multiple sinusoidal waveforms, thereby detecting the displacement of the first calibration position. The processor determines whether the first calibration position moves outside the range of the first detection member 4. If the processor detects that the induced voltage of the first detection member 4 changes suddenly, it is determined that the first calibration position moves outside the range of the first detection member 4.

[0050] In a specific embodiment, step S3 also includes:

[0051] L=K*D+n*K*360°+sign*(LL).

[0052] Wherein, L is the total displacement of the first calibration position, sign is the direction of movement of the first calibration position, K is the coefficient between the angle of rotation of the steering motor 3 and the displacement of the first calibration position, D is the difference between the angle of the steering motor 3 and the angle of the steering motor 3 when the first detection member 4 is at the maximum range, n is the number of turns of the steering motor 3 after it exceeds the range at the first calibration position, and LL is the absolute value of the range of the first detection member 4.

[0053] In a specific example, K can be calculated by a fixed transmission ratio between the steering motor 3 and the rack 2, for example, the motor rotates 800° and the rack 2 moves 1 mm, that is, K=1 / 800 (unit: mm / °). Those skilled in the art can set the value of K as needed.

[0054] The value processor of sign can be determined by integrating the forward and reverse rotation of the steering motor 3. Specifically, when the steering motor 3 rotates 360° in the forward direction or 360° in the reverse direction, the angle value changes from 0° to 360° to 0° and then to 360°. When rotating in the reverse direction, the angle value of the steering motor 3 changes from 360° to 0° to 360° and then to 0°. Such a numerical change process will form a sudden change in the rotation angle of the steering motor 3. By sampling the rotation speed of the steering motor 3, the sudden change of the angle is identified, and then according to the change of the sampled angle, it can be judged whether the steering motor 3 rotates from 360° to 0° or from 0° to 360°, and then it can be judged whether the steering motor 3 rotates forward or reverse.

[0055] When the steering motor 3 passes through its angle zero point, the value of n is calculated by the following formula: n=n'±1.

[0056] Specifically, n' is the number of revolutions of the steering motor 3 at the previous moment recorded by the vehicle ECU, and the positive or negative value of 1 is determined by identifying whether the steering motor 3 is rotating forward or reverse through the angle change, thereby obtaining the value of n.

[0057] The measuring range of the first detection member 4 is, for example, ±50 mm with the second calibration position as the zero point, wherein when the first calibration position moves to the left relative to the second calibration position, it is a negative value, and when the first calibration position moves to the right relative to the second calibration position, it is a positive value.

[0058] If at this time, the first calibration position of the rack 2 moves to the right to +50mm and then continues to move, it will exceed the measuring range of the first detection member 4, so that the first detection member 4 cannot measure the moving position of the rack 2. At this time, the angle sensor 31 detects that after the first calibration position exceeds the measuring range of the first detection member 4, the steering motor 3 rotates another 800°. That is, LL=50mm, n=2, D=80°. That is, the total displacement of the first calibration position is L=1 / 800*80+2*360*1 / 800+1*(50)=51mm. Among them, the value of n can be calculated by software.

[0059] In some embodiments, the control method further includes:

[0060] S4. Before the vehicle is ignited, the first calibration position is returned to the range of the first detection member 4;

[0061] S5. Determine whether the homing is successful;

[0062] S6. If the homing is unsuccessful, the first calibration position is returned to the range of the first detection member 4 after the vehicle is ignited;

[0063] S7. Determine again whether the homing is successful.

[0064] S8. If homing is unsuccessful, a fault is reported.

[0065] After the processor determines that the first calibration position of the rack 2 exceeds the range, the displacement of the first calibration position is determined by the angle sensor 31 and the first detection member 4. Before the vehicle is ignited, the processor controls the steering motor 3 to drive the rack 2 to move in the reverse direction to within the range of the first detection member 4.

[0066] In order to determine whether the first calibration position is successfully returned, a return flag is stored in the processor, wherein the processor is the vehicle's ECU (Electronic Control Unit), and when the first calibration position of the rack 2 moves to the flag, it is considered to be successfully returned.

[0067] Specifically, the first calibration position returns to be aligned with the second calibration position, or the first calibration position moves to a specific set position within the range of the first detection member 4. Those skilled in the art can set it as needed.

[0068] When the first calibration position automatically returns to be aligned with the second calibration position, the wheel 6 automatically returns to the straight-ahead position, that is, the rotation angle of the wheel 6 is 0° at this time.

[0069] For example, if the steering motor 3 of the vehicle fails, the wheel 6 is stuck, or the lower steering assembly has a mechanical failure, the rack 2 cannot be returned to its original position before the vehicle is ignited. When the rack 2 cannot be returned to its original position before the vehicle is ignited, the steering motor 3 drives the rack 2 to return to its original position again after the vehicle is ignited. If it returns to its original position normally, the vehicle runs normally. If it still cannot return to its original position, a fault is reported.

[0070] Optionally, in another embodiment, step S2 further includes:

[0071] S21. When the vehicle is turned off, determine whether the first calibration position exceeds the range.

[0072] When the judgment result is no, the vehicle is turned off.

[0073] When the judgment result is yes, before the vehicle is ignited, the first calibration position is returned to within the measuring range of the first detection member.

[0074] In a specific embodiment, when the vehicle is turned off, the processor determines whether the first calibration position is returned to within the range of the first detection member 4. When the determination result of the processor is yes, the vehicle is turned off.

[0075] If the judgment result is negative, the first calibration position is returned to within the measuring range of the first detection member before the vehicle is ignited.

[0076] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A lower steering assembly, characterized in that: include: A rack is drivingly connected to the wheel, the rack can move laterally relative to the vehicle, an adapter is provided on the outer peripheral surface of the rack, and the adapter is provided with a first calibration position; A first detection member is provided with a second calibration position, wherein the first detection member comprises an excitation coil and a plurality of induction coils; A processor, connected to the first detection element by signal; When the rack moves, the excitation coil interacts with the adapter to excite a magnetic field signal, the induction coil can receive the magnetic field signal and form a signal pulse, and the processor determines the movement distance of the first calibrated position relative to the second calibrated position based on the signal pulse.

2. The lower steering assembly according to claim 1, characterized in that: The excitation coil is rectangular; The induction coil is arranged inside the area surrounded by the excitation coil, each of the induction coils is arranged in a plurality of rhombuses, and a plurality of the induction coils are arranged in a staggered manner.

3. The lower steering assembly according to claim 2, characterized in that: It comprises a plurality of the adapters, which are spaced apart in sequence along the axial direction of the rack, and the first calibration position is calibrated at one of the adapters.

4. The lower steering assembly according to any one of claims 1 to 3, characterized in that: The adapter and the rack are an integrated structure.

5. The lower steering assembly according to claim 4, characterized in that: The adapter extends from the main body of the rack into a T-shape, and the T-shaped adapter includes a thin sensing sheet, and the sensing sheet is used to cooperate with the excitation coil; The adapter also includes a connecting portion connected between the rack main body and the sensing piece.

6. A steering system, characterized in that: include: Upper steering assembly; The lower steering assembly according to any one of claims 1 to 5, wherein the upper steering assembly is signal-connected to the lower steering assembly; The lower steering assembly also includes a steering motor, which is used for drivingly connecting with the rack to drive the rack to move laterally along the vehicle; An angle sensor is connected to the processor signal and is used to detect the rotation angle of the steering motor.

7. A control method for a steering system according to claim 6, characterized in that: include: When the rack moves, the excitation coil interacts with the adapter to excite a magnetic field signal; The induction coil is capable of receiving the magnetic field signal and forming a signal pulse; The processor determines a movement distance of the first calibrated position relative to the second calibrated position according to the signal pulse.

8. The control method according to claim 7, characterized in that: Also includes: determining whether the first calibration position is moved outside the measuring range of the first detection member; When the judgment result is yes, determining the total displacement of the first calibration position according to the rotation angle of the steering motor; The total displacement includes the sum of the displacement of the first calibrated position within the measuring range of the first detection member and the displacement beyond the measuring range.

9. The control method according to claim 8, characterized in that: The total displacement of the first calibration position is obtained by the following formula: L=K*D+n*K*360°+sign*(LL); Among them, L is the total displacement of the first calibration position, sign is the direction of movement of the first calibration position, K is the coefficient between the rotation angle of the steering motor and the displacement of the first calibration position, D is the difference between the current angle of the steering motor and the angle of the steering motor when the first detection member is at the maximum range, n is the number of turns of the steering motor after the rack exceeds the range, and LL is the absolute value of the range of the first detection member.

10. The control method according to claim 9, characterized in that: Also includes: Before the vehicle is ignited, the first calibration position is returned to within the measuring range of the first detection member; Determine whether homing is successful; If the judgment result is negative, returning the first calibration position to within the measuring range of the first detection member after the vehicle is ignited; Determine again whether the homing is successful. If the judgment result is no, a fault is reported.

11. The control method according to claim 10, characterized in that: The step of determining whether the first calibration position has moved out of the measuring range of the first detection member further includes: When the vehicle is turned off, it is determined whether the first calibration position exceeds the measuring range of the first detection member.

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