Simulation method and system for mechanical steering of steering wheel of SBW vehicle

Abstract

The invention relates to a simulation method and system for mechanical steering of a steering wheel of an SBW vehicle. The simulation method comprises the following steps that S1, whether a rack reaches the final position or not is recognized; s2, in response to the fact that the rack arrives at the final position, soft stop resistance torque is provided, and the soft stop resistance torque is increased based on the steering speed of a steering wheel; s3, whether the rack returns to the neutral position or not is recognized; and S4, in response to the situation that the rack returns to the neutral position, soft stop resistance torque is provided, and the soft stop resistance torque is reduced based on the rotation speed of the steering wheel. And when the rack reaches the final position or the neutral position, the soft stop resistance torque is increased or decreased according to the steering speed and the rotation speed of the steering wheel, so that the steering wheel is prevented from over-steering, the rack crosses a mechanical stop point or the steering wheel is prevented from suddenly rotating. No additional mechanical device is needed, mechanical steering of a real steering wheel is simulated, operation is simple, and comfortable and safe driving hand feeling can be provided for a driver.

Description

Technical Field

[0001] The present invention relates to the technical field of SBW vehicles, and in particular to a simulation method and system for mechanical steering of a steering wheel of a SBW vehicle. Background Art

[0002] Electric power steering by wire (SBW) means that there is no direct mechanical connection between the steering wheel and the wheels, and the steering wheel controls the wheels through cables. Figure 1 As shown, the steering system of the SBW vehicle includes HWA and RWA, where HWA is a steering wheel actuator and RWA is a wheel actuator. Since there is no mechanical structure restriction between the two, the steering wheel in the SBW vehicle can rotate without restriction, but the steering wheel of a traditional car is directly connected to the wheel through a mechanical structure, so the steering wheel can only rotate within a range of 540° to 720°.

[0003] Therefore, the steering system of the SBW vehicle must also have the corresponding function to remind the driver. When the steering wheel is turned, HWA will provide a hand torque feedback to simulate the resistance torque transmitted to the steering wheel by the wheels of a traditional car when turning. When the driver turns the steering wheel and the rack that controls the steering of the wheels moves to the end position, HWA needs to generate a large hand torque feedback to remind the driver that the current rack has moved to the end position and warn the driver that the current vehicle's steering system is at the steering limit position.

[0004] However, when the rack reaches the end position, the hand torque feedback direction generated by the HWA is opposite to the torque direction of the driver turning the steering wheel, and this hand torque feedback is very large without restriction. Therefore, when the rack reaches the end position, if the driver suddenly releases his hands on the steering wheel or turns the steering wheel to the neutral position, the hand torque feedback may cause an obvious angular velocity on the steering wheel, causing the steering wheel to turn back quickly. This is a bad feeling and is also very unsafe. Therefore, necessary measures need to be taken to prevent this from happening. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the present disclosure provides a simulation method and system for mechanical steering of a steering wheel of a SBW vehicle.

[0006] According to the first aspect of an embodiment of the present disclosure, the present disclosure provides a simulation method for mechanical steering of a steering wheel of an SBW vehicle, comprising the following steps: Step S1: Identify whether the rack has reached the end position; Step S2: In response to the rack reaching the end position, increase the feedback resistance torque based on the steering speed of the steering wheel and the position of the rack; Step S3: Identify whether the rack will return to a neutral position; Step S4: In response to the rack returning to the neutral position, reduce the feedback resistance torque based on the rotation speed of the steering wheel and the position of the rack.

[0007] In some embodiments, in step S1 and step S3, whether the rack reaches the end position and the neutral position is identified based on the steering angle of the steering wheel and the position of the rack.

[0008] In some embodiments, in the step S2, it specifically includes: step S21, in response to the rack reaching the end position, establishing a torque gradient function of the rack position and the soft stop resistance torque; step S22, determining a reinforcement coefficient based on the steering speed of the steering wheel; step S23, increasing the soft stop resistance torque based on the reinforcement coefficient.

[0009] In some embodiments, the reinforcement coefficient is positively correlated with the steering speed of the steering wheel.

[0010] In some embodiments, the step S4 specifically includes: step S41, determining an attenuation coefficient based on the rotation speed of the steering wheel; step S42, reducing the soft stop resistance torque based on the attenuation coefficient.

[0011] In some embodiments, the attenuation coefficient is negatively correlated with the rotation speed of the steering wheel.

[0012] According to a second aspect of an embodiment of the present disclosure, the present disclosure provides a simulation system for mechanical steering of a steering wheel of an SBW vehicle, comprising: a first identification unit, configured to identify whether a rack has reached an end position; a first execution unit, configured to provide a soft stop resistance torque in response to the rack reaching the end position, and to increase the soft stop resistance torque based on the steering speed of the steering wheel; a second identification unit, configured to identify whether the rack has returned to a neutral position; and a second execution unit, configured to provide a soft stop resistance torque in response to the rack returning to a neutral position, and to reduce the soft stop resistance torque based on the rotation speed of the steering wheel.

[0013] In some embodiments, in the first recognition unit and the second recognition unit, whether the rack reaches an end position and a neutral position is recognized based on a steering angle of a steering wheel and a position of a rack.

[0014] In some embodiments, in the first execution unit, it is specifically configured to establish a torque gradient function of the rack position and the soft stop resistance torque in response to the rack reaching the end position, determine a reinforcement coefficient based on the steering speed of the steering wheel, and increase the soft stop resistance torque based on the reinforcement coefficient, wherein the reinforcement coefficient is positively correlated with the steering speed of the steering wheel.

[0015] In some embodiments, in the second execution unit, it is specifically configured to determine an attenuation coefficient based on the rotation speed of the steering wheel; based on the attenuation coefficient, reduce the soft stop resistance torque, wherein the attenuation coefficient is negatively correlated with the rotation speed of the steering wheel.

[0016] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: On the one hand, when the steering wheel controls the rack to move to the terminal position, the soft stop resistance torque can be increased according to the steering speed of the steering wheel to prevent the steering wheel from oversteering and causing the rack to cross the mechanical stop point. When the steering wheel controls the rack to move to the neutral position, the soft stop resistance torque can be reduced according to the rotation speed of the steering wheel to avoid sudden rotation of the steering wheel and improve driving safety. On the other hand, the present disclosure can simulate the real mechanical steering of the steering wheel without the need for additional mechanical devices, so that the driver has a better feel, is simple to operate, and has strong adaptability, and can provide the driver with a comfortable and safe feel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0018] Figure 1 It is a structural schematic diagram of a steering system of a SBW vehicle in the related art;

[0019] Figure 2 is a flow chart of a simulation method for mechanical steering of a steering wheel of a SBW vehicle according to an exemplary embodiment;

[0020] Figures 3 to 5 are three relationship diagrams of rack position and torque gradient function of soft stop feed resistance torque;

[0021] Figure 6 yes Figure 2 Another form of flow chart. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0023] In order to solve the above technical problems, the present disclosure provides a simulation method for mechanical steering of a steering wheel of a SBW vehicle, such as Figure 2 As shown, the following steps are included: Step S1: identifying whether the rack reaches the end position; Step S2: in response to the rack reaching the end position, providing a soft stop resistance torque, and increasing the soft stop resistance torque based on the steering speed of the steering wheel; Step S3: identifying whether the rack returns to the neutral position; Step S4: in response to the rack returning to the neutral position, providing a soft stop resistance torque, and reducing the soft stop resistance torque based on the rotation speed of the steering wheel.

[0024] The steering system of the SBW vehicle includes a steering wheel actuator HWA and a wheel actuator RMA, wherein the wheel actuator RWA includes a rack and a pull rod, wherein the rack is connected to the pull rod, the rack pulls the pull rod through linear motion, and the pull rod is connected to the wheel, thereby pulling the wheel to rotate and realizing the steering of the vehicle. Therefore, when the rack moves to the end position, it means that the wheel is in the extreme steering position, and when the rack moves to the neutral position, it means that the direction of the wheel is consistent with the longitudinal direction of the vehicle. There are two end positions of the rack, which are located at the left and right ends of the vehicle, respectively representing the left extreme steering position and the right extreme steering position.

[0025] Furthermore, in step S1 and step S3, based on the steering angle of the steering wheel and the position of the rack, it is identified whether the rack reaches the end position and the neutral position.

[0026] The steering angle of the steering wheel and the position of the rack are measured by the sensor, and the signal measured by the sensor is transmitted to the vehicle control center, which then identifies whether the steering wheel moves from the neutral position to the end position or from the end position to the neutral position. When it is identified that the steering wheel moves from the neutral position to the end position, and based on the steering angle of the steering wheel and the specific position of the rack, it is identified that the rack reaches the end position or the neutral position, the wheel actuator RWA provides a soft stop resistance torque.

[0027] Further, step S2 specifically includes: step S21, in response to the rack reaching the end position, such as Figures 3 to 5As shown, a torque gradient function of the rack position and the soft stop resistance torque is established, and a soft stop resistance torque is provided; step S22, determining a reinforcement coefficient based on the steering speed of the steering wheel; step S23, increasing the soft stop resistance torque based on the reinforcement coefficient.

[0028] Among them, Figures 3 to 5 It can be seen from the displayed torque gradient function that before the rack reaches the left end position and the right end position (shown on the horizontal axis), the soft stop resistance torque (shown on the vertical axis) is displayed as 0, but it does not mean that when the rack is between the left end position and the right end position, the actual resistance torque provided by the motor is 0. In fact, when the rack is between the left end position and the right end position, the motor always provides resistance torque to simulate the real mechanical resistance of the steering wheel and improve the driving feel of the driver, but it is not within the scope of protection of the present disclosure and is therefore omitted. The present disclosure only discusses the soft stop resistance torque provided by the motor when the rack reaches the left end position and the right end position.

[0029] When the rack reaches the left end position or the right end position, the relationship between the rack position and the soft stop resistance torque can be linear (such as Figure 3 ), or it can be nonlinear (as shown in Figure 4 and Figure 5 The linear or nonlinear relationship between the rack position and the soft stop resistance torque can be adjusted according to the driver's specific feel or habits when gripping the steering wheel.

[0030] In step S22, the steering speed of the steering wheel is the rotation speed of the steering wheel when it rotates from the neutral position to the end position. In one embodiment, the relationship between the enhancement coefficient and the steering speed of the steering wheel is shown in Table 1 below.

[0031] 0rpm 100rpm 200rpm 300rpm 400rpm 1 1.1 1.2 1.3 1.4

[0032] The first row in Table 1 represents the steering speed of the steering wheel, and the steering speed of the steering wheel is represented by a positive number; the second row in Table 1 represents the reinforcement coefficient. It can be seen from Table 1 that the reinforcement coefficient is positively correlated with the steering speed of the steering wheel, that is, the greater the steering speed of the steering wheel, the greater the reinforcement coefficient. The reinforcement coefficient is multiplied by Figures 3 to 5 The soft stop resistance torque corresponding to the middle vertical coordinate can increase the soft stop resistance torque when the steering wheel turns quickly.

[0033] Furthermore, step S4 specifically includes: step S41, determining the attenuation coefficient based on the rotation speed of the steering wheel; step S42, reducing the soft stop resistance torque based on the attenuation coefficient.

[0034] In step S42, the rotation speed of the steering wheel is the rotation speed of the steering wheel when it rotates from the end position to the neutral position. In one embodiment, the relationship between the attenuation coefficient and the steering speed of the steering wheel is shown in Table 2 below.

[0035] -400rpm -300rpm -200rpm -100rpm 0rpm 0.6 0.7 0.8 0.9 1

[0036] The first row in Table 2 represents the rotation speed of the steering wheel, and the rotation speed of the steering wheel is represented by a negative number; the second row in Table 2 represents the attenuation coefficient. It can be seen from Table 2 that the attenuation coefficient is negatively correlated with the rotation speed of the steering wheel, that is, the greater the rotation speed of the steering wheel, the smaller the attenuation coefficient. The attenuation coefficient is multiplied by Figures 3 to 5 The soft stop resistance torque corresponding to the middle vertical coordinate can reduce the soft stop resistance torque when the steering wheel is turned quickly.

[0037] In summary, through the method disclosed in the present invention, when the steering wheel is turned and the rack is controlled to move toward the terminal position, the soft stop resistance torque can be increased according to the steering speed of the steering wheel to prevent the rack from crossing the mechanical stop point due to the transition of the steering wheel. When the steering wheel is turned to control the rack to move toward the neutral position, the soft stop resistance torque can also be reduced according to the rotation speed of the steering wheel to avoid sudden rotation of the steering wheel and improve driving safety. In addition, the present invention can simulate the real mechanical steering of the steering wheel without the need for additional mechanical devices, so that the driver has a better feel, simple operation, strong adaptability, and can provide the driver with a comfortable and safe driving feel.

[0038] It should be noted that the corresponding relationship between the steering speed of the steering wheel and the reinforcement coefficient in Table 1, and the corresponding relationship between the rotation speed of the steering wheel and the attenuation coefficient in Table 2 are only exemplary and are not intended to limit the protection scope of the present disclosure. In some other embodiments, the reinforcement coefficient corresponding to the steering speed of the steering wheel, and the attenuation coefficient corresponding to the rotation speed of the steering wheel, can be calibrated and adjusted according to the specific feel, and are not specifically limited here.

[0039] Based on the same inventive concept, the present disclosure provides a simulation system for steering wheel mechanical steering of an SBW vehicle, comprising: a first identification unit, configured to identify whether the rack has reached the end position; a first execution unit, configured to provide a soft stop resistance torque in response to the rack reaching the end position, and to provide the soft stop resistance torque based on the steering speed of the steering wheel; a second identification unit, configured to identify whether the rack returns to a neutral position; a second execution unit, configured to provide a soft stop resistance torque in response to the rack returning to the neutral position, and to reduce the soft stop resistance torque based on the rotation speed of the steering wheel.

[0040] In some embodiments, in the first recognition unit and the third recognition unit, based on the steering angle of the steering wheel and the rack position, it is recognized whether the rack reaches the end position and the neutral position.

[0041] In some embodiments, in the first execution unit, a torque gradient function of the rack position and the soft stop resistance torque is established in response to the rack reaching the end position, a reinforcement coefficient is determined based on the steering speed of the steering wheel, and the soft stop resistance torque is adjusted based on the reinforcement coefficient, wherein the reinforcement coefficient is positively correlated with the steering speed of the steering wheel.

[0042] In some embodiments, in the second execution unit, a specific configuration is to determine an attenuation coefficient based on the rotation speed of the steering wheel; based on the attenuation coefficient, reduce the soft stop resistance torque, wherein the attenuation coefficient is negatively correlated with the rotation speed of the steering wheel.

[0043] The specific methods of implementing the functions in the simulation system for mechanical steering of the steering wheel for SBW vehicles in the above-mentioned embodiment have been described in detail in the embodiment of the simulation method for mechanical steering of the steering wheel for SBW vehicles, and will not be elaborated here.

[0044] It is to be understood that in the present disclosure, "plurality" refers to two or more than two, and other quantifiers are similar. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The singular forms "a", "the" and "the" are also intended to include plural forms, unless the context clearly indicates other meanings.

[0045] It is further understood that the terms "first", "second", etc. are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from each other, and do not indicate a specific order or importance. In fact, the expressions "first", "second", etc. can be used interchangeably. For example, without departing from the scope of the present disclosure, a first structure can also be referred to as a second structure, and similarly, a second structure can also be referred to as a first structure.

[0046] It can be further understood that, unless otherwise specified, “connection” includes a direct connection without other components between the two, and also includes an indirect connection with other components between the two.

[0047] It is further understood that, although the operations are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood as requiring the operations to be performed in the specific order shown or in a serial order, or requiring the execution of all the operations shown to obtain the desired results. In certain environments, multitasking and parallel processing may be advantageous.

[0048] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following scope of rights.

[0049] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the scope of the appended claims.

Claims

1. A method for simulating mechanical steering of a steering wheel of a SBW vehicle, characterized in that: The following steps are involved: Step S1: Identify whether the rack reaches the end position; Step S2: in response to the rack reaching the end position, providing a soft stop resistance torque, and increasing the soft stop resistance torque based on the steering speed of the steering wheel; Step S3: Identify whether the rack returns to the neutral position; Step S4: In response to the rack gear returning to the neutral position, providing a soft stop resistance torque, and reducing the soft stop resistance torque based on the rotation speed of the steering wheel.

2. The method for simulating mechanical steering of a steering wheel for a SBW vehicle according to claim 1, characterized in that: In the step S1 and the step S3, whether the rack reaches the end position and the neutral position is identified based on the steering angle of the steering wheel and the rack position.

3. The method for simulating mechanical steering of a steering wheel for a SBW vehicle according to claim 1, characterized in that: In the step S2, it specifically includes: Step S21, in response to the rack reaching the end position, establishing a torque gradient function of the rack position and the soft stop resistance torque; Step S22, determining a reinforcement coefficient based on the steering speed of the steering wheel; Step S23: increasing the soft stop resistance torque based on the reinforcement coefficient.

4. The method for simulating mechanical steering of a steering wheel for a SBW vehicle according to claim 3, characterized in that: The reinforcement coefficient is positively correlated with the steering speed of the steering wheel.

5. The method for simulating mechanical steering of a steering wheel for a SBW vehicle according to claim 1, characterized in that: In the step S4, it specifically includes: Step S41, determining the attenuation coefficient based on the rotation speed of the steering wheel; Step S42: reducing the soft stop resistance torque based on the attenuation coefficient.

6. The method for simulating mechanical steering of a steering wheel for a SBW vehicle according to claim 5, characterized in that: The attenuation coefficient is negatively correlated with the rotation speed of the steering wheel.

7. A simulation system for mechanical steering of a steering wheel of a SBW vehicle, characterized in that: include: A first recognition unit configured to recognize whether the rack reaches an end position; a first execution unit configured to provide a soft stop resistance torque in response to the rack reaching an end position, and to increase the soft stop resistance torque based on a steering speed of the steering wheel; a second identification unit configured to identify whether the rack returns to a neutral position; The second actuator is configured to provide a soft-stop resistance torque in response to the rack returning to a neutral position, and reduce the soft-stop resistance torque based on a rotation speed of the steering wheel.

8. The simulation system for mechanical steering of a steering wheel of a SBW vehicle according to claim 7, characterized in that: In the first recognition unit and the second recognition unit, whether the rack reaches an end position and a neutral position is recognized based on a steering angle of a steering wheel and a rack position.

9. The simulation system for mechanical steering of a steering wheel of a SBW vehicle according to claim 7, characterized in that: In the first execution unit, it is specifically configured to establish a torque gradient function of the rack position and the soft stop resistance torque in response to the rack reaching the end position, determine a reinforcement coefficient based on the steering speed of the steering wheel, and increase the soft stop resistance torque based on the reinforcement coefficient, wherein the reinforcement coefficient is positively correlated with the steering speed of the steering wheel.

10. The simulation system for mechanical steering of a steering wheel of a SBW vehicle according to claim 7, characterized in that: In the second execution unit, it is specifically configured to determine an attenuation coefficient based on the rotation speed of the steering wheel; and reduce the soft stop resistance torque based on the attenuation coefficient, wherein the attenuation coefficient is negatively correlated with the rotation speed of the steering wheel.

Images