A method for coordinated control of a dual-motor steering system and the steering system itself.

Abstract

This invention discloses a dual-motor steering system collaborative control method and steering system, belonging to the field of vehicle technology. The dual-motor steering system includes a first motor controller and a second motor controller. The method includes: acquiring a fault signal from the first motor controller; determining the operating mode of the first motor controller based on the fault signal; and determining the operating mode of the second motor controller based on the operating mode of the first motor controller. The operating modes of the motor controllers include rated power assist mode, power assist downgrade mode, no power assist mode, and power assist overload mode. This invention, by setting multiple operating modes for the motor controllers, determines the operating mode of the second motor controller based on the operating mode of the first motor controller when a fault occurs. This smooth switching of operating modes avoids sudden torque changes and improves the user's driving experience.

Description

Technical Field

[0001] This invention belongs to the field of vehicle technology, specifically relating to a dual-motor steering system cooperative control method and steering system. Background Technology

[0002] Dual-motor steering systems are equipped with two motors. If one motor fails, the other, which is functioning normally, can provide torque, thus meeting the power steering requirements through redundant control. However, in these technologies, a significant torque fluctuation can occur when a fault occurs, affecting the user's driving experience. Summary of the Invention

[0003] One objective of this invention is to provide a dual-motor steering system coordinated control method and steering system, which can solve the technical problem of large torque fluctuations when a fault occurs in the prior art.

[0004] According to a first aspect of the present invention, a method for coordinated control of a dual-motor steering system is provided, the dual-motor steering system comprising a first motor controller and a second motor controller, the method comprising:

[0005] Obtain the fault signal from the first motor controller;

[0006] The operating mode of the first motor controller is determined based on the fault signal of the first motor controller;

[0007] The operating mode of the second motor controller is determined based on the operating mode of the first motor controller.

[0008] The motor controller has four operating modes: rated assist mode, assist degraded mode, no assist mode, and assist overload mode. In the rated assist mode, the motor controller outputs assist according to the calibration parameters. In the assist degraded mode, the motor controller reduces the motor output assist value according to the attenuation curve. In the no assist mode, the motor controller does not output assist. In the assist overload mode, the motor controller outputs assist value exceeding the motor controller output assist value in the rated assist mode by a preset ratio.

[0009] Optionally, determining the operating mode of the first motor controller based on the fault signal of the first motor controller includes:

[0010] The fault status of the first motor controller is determined based on the fault signal of the first motor controller;

[0011] The operating mode of the first motor controller is determined based on the fault status of the first motor controller.

[0012] Optionally, the fault status includes a fault-free status, a fault diagnosis range without confirmation status, a fault confirmation status, and a normal signal range with fault not cleared status.

[0013] Optionally, determining the operating mode of the first motor controller based on the fault state of the first motor controller includes:

[0014] If the fault status of the first motor controller is fault-free, the operating mode of the first motor controller is determined to be rated assist mode.

[0015] If the fault status of the first motor controller is "entering the fault diagnosis range but the fault status is not confirmed", then the operating mode of the first motor controller is determined to be the assist degrade mode.

[0016] If the fault status of the first motor controller is either a fault confirmation state or a state where the fault has not been eliminated even after entering the normal signal range, the operating mode of the first motor controller is determined to be the no-assist mode.

[0017] Optionally, the fault signal includes a torque sensor fault signal, an angle sensor fault signal, and a motor drive circuit fault signal.

[0018] Optionally, determining the fault state of the first motor controller based on the fault signal of the first motor controller includes:

[0019] Determine the fault level for each fault signal;

[0020] The fault status of the first motor controller is determined based on the highest fault level.

[0021] Optionally, determining the operating mode of the second motor controller based on the operating mode of the first motor controller includes:

[0022] When the first motor controller is in the no-assist mode, the second motor controller enters the assist overload mode;

[0023] When the first motor controller is in the assist degrade mode, the second motor controller enters the assist overload mode. In the assist overload mode, the second motor controller enters the rated assist mode after meeting the preset conditions.

[0024] When the first motor controller is in rated assist mode, the second motor controller enters rated assist mode.

[0025] Optionally, the first motor controller and the second motor controller use two CAN signals for information exchange, including public CAN and private CAN;

[0026] The public CAN is used to transmit communication protocol content confirmed with the OEM.

[0027] The private CAN is used to transmit the fault status of the two motor controllers.

[0028] Optionally, the first motor controller and the second motor controller use independent power supplies and independent vehicle signals.

[0029] This embodiment introduces a steering gear, including a processor and a memory. The memory stores programs or instructions that can be executed by the processor. When the program or instructions are executed by the processor, they implement the steps of the dual-motor steering gear cooperative control method described in the first aspect of this invention.

[0030] The beneficial effects of the present invention are as follows: By setting multiple working modes of the motor controller, when a fault occurs, the working mode of the second motor controller is determined according to the working mode of the first motor controller. The smooth switching of working modes avoids sudden torque changes and improves the user's driving experience. Attached Figure Description

[0031] Figure 1 This is a flowchart of a dual-motor steering system collaborative control method according to the present invention. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0033] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0034] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0036] In the specification of this invention, the terms "first" and "second" may explicitly or implicitly include one or more of the same feature. In the description of this invention, unless otherwise stated, "multiple" means two or more. Furthermore, in the specification, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0037] like Figure 1 As shown in the figure, this embodiment introduces a dual-motor steering system collaborative control method. The dual-motor steering system includes a first motor controller and a second motor controller. The method includes steps 1100-1300.

[0038] Step 1100: Obtain the fault signal from the first motor controller.

[0039] The dual-motor steering system of this invention includes two motor controllers, namely a first motor controller and a second motor controller, which work together to output power assistance.

[0040] During operation, motor controllers may experience various types of faults. The specific fault is determined by acquiring fault signals. The first motor controller is the one that has failed. For example, in a dual-motor steering system, there are motor controllers A and B. If motor controller A fails, then motor controller A is the first motor controller. If motor controller B fails, then motor controller B is the first motor controller.

[0041] Step 1200: Determine the operating mode of the first motor controller based on the fault signal of the first motor controller.

[0042] The operating modes of the motor controller include rated assist mode, assist degraded mode, no assist mode, and assist overload mode.

[0043] In the rated assist mode, the motor controller outputs assist according to the calibration parameters. By pre-calibrating the parameters, the motor controller outputs assist according to the calibration parameters in the rated assist mode.

[0044] In the degraded assist mode, the motor controller reduces the motor's output assist value according to the attenuation curve. The attenuation curve is also pre-calibrated; in degraded assist mode, the assist value output by the motor controller decreases according to the attenuation curve. The assist value output by the motor controller in degraded assist mode is less than the assist value output by the motor controller in rated assist mode.

[0045] In the no-assist mode, the motor controller does not output assistance.

[0046] In the overload assist mode, the assist value output by the motor controller exceeds the assist value output by the motor controller in the rated assist mode by a preset ratio. For example, the assist value output by the motor controller in the overload assist mode is greater than the assist value output by the motor controller in the rated assist mode; in the overload assist mode, the motor controller outputs a 120% assist value.

[0047] When the motor controller experiences different types of faults, it will enter the corresponding operating mode based on the specific fault type.

[0048] Step 1300: Determine the operating mode of the second motor controller based on the operating mode of the first motor controller.

[0049] During the operation of the dual-motor steering system, the two motor controllers work together to provide power assistance. The steering torque is the sum of the driver's hand force, the power assistance output from the first motor controller, and the power assistance output from the second motor controller.

[0050] When the first motor controller malfunctions, its operating mode changes, causing a change in the power assist output. To avoid sudden changes in steering torque, the operating mode of the second motor controller needs to be adjusted, thus altering its power assist output.

[0051] This invention sets multiple operating modes for the motor controller. When a fault occurs, the operating mode of the second motor controller is determined based on the operating mode of the first motor controller. By smoothly switching between operating modes, sudden torque changes are avoided, thus improving the user's driving experience.

[0052] In this embodiment, step 1200 includes steps 1210-1220.

[0053] Step 1210: Determine the fault status of the first motor controller based on the fault signal of the first motor controller.

[0054] Specifically, the fault states include a fault-free state, a fault diagnosis range without confirmation state, a fault confirmation state, and a normal signal range without fault elimination state.

[0055] A fault-free status indicates that the motor controller has not malfunctioned.

[0056] Entering the fault diagnosis range without a confirmed fault status means that the system has detected abnormal signals, but has not yet made a final determination of a fault.

[0057] The fault confirmation status indicates that the system has confirmed that a fault has actually occurred.

[0058] Even if the signal has returned to normal and the fault has not been cleared when the signal enters the normal signal range, the system still remembers that the fault occurred until a specific reset condition is met. This method prevents the system from repeatedly fluctuating during intermittent faults, ensuring stability.

[0059] By acquiring the fault code corresponding to the fault signal and pre-configuring different fault states of the motor controller corresponding to different fault codes, the fault state of the first motor controller is determined based on the fault code of the fault signal and the above correspondence.

[0060] Step 1220: Determine the operating mode of the first motor controller based on the fault status of the first motor controller.

[0061] Specifically, step 1220 includes steps 1221-1223.

[0062] Step 1221: If the fault status of the first motor controller is fault-free, determine that the operating mode of the first motor controller is rated assist mode.

[0063] When the first motor controller is functioning correctly, its fault status is "fault-free". Under these conditions, the first motor controller operates normally in rated assist mode, outputting assist according to the calibrated parameters.

[0064] Step 1222: If the fault status of the first motor controller is "entering the fault diagnosis range but not confirmed", determine that the working mode of the first motor controller is the assist degrade mode.

[0065] If the fault diagnosis is entered but the fault status is not confirmed, it means that the system has detected an abnormal signal, but it has not yet been determined whether it is a fault. To ensure safety, the first motor controller is put into assist degrade mode, reducing the assist output of the first motor controller.

[0066] Step 1223: If the fault status of the first motor controller is either fault confirmation status or fault not cleared within the normal signal range, determine that the working mode of the first motor controller is non-assisted mode.

[0067] After confirming that the first motor controller has malfunctioned, the first motor controller is put into a no-assist mode to stop outputting assist.

[0068] In this embodiment, the fault signals include torque sensor fault signals, angle sensor fault signals, and motor drive circuit fault signals.

[0069] Specifically, step 1210 includes steps 1211-1212.

[0070] Step 1211: Determine the fault level of each fault signal.

[0071] Step 1212: Determine the fault status of the first motor controller based on the highest fault level.

[0072] The fault signal is classified into four levels, corresponding to four fault states. Level 1 is a fault-free state; Level 2 is a state where the fault is not confirmed within the fault diagnosis range; Level 3 is a state where the fault is confirmed; and Level 4 is a state where the fault is not eliminated within the normal signal range.

[0073] Since there are multiple fault signals, each with a different fault level, the highest fault level is used as the basis for determining the fault status of the first motor controller. For example, if the torque sensor fault signal is level one, the angle sensor signal is level three, and the motor drive circuit fault signal is level two, then the highest fault level is level three. In this case, the fault status of the first motor controller is determined to be a fault confirmation state.

[0074] In this embodiment, step 1300 includes steps 1310-1330.

[0075] Step 1310: When the first motor controller is in the no-assist mode, the second motor controller enters the assist overload mode.

[0076] When the first motor controller is in no-assist mode, the second motor controller enters assist overload mode, outputting 120% assist to ensure vehicle steering. Compared to normal conditions, the assist output of the power steering system is reduced.

[0077] Step 1320: When the first motor controller is in the assist degrade mode, the second motor controller enters the assist overload mode. In the assist overload mode, the second motor controller enters the rated assist mode after meeting the preset conditions.

[0078] When the first motor controller is in assist degrade mode, the assist output of the first motor controller is reduced, so the assist output of the second motor controller needs to be increased to allow the second motor controller to enter assist overload mode.

[0079] In the power steering degrade mode, the first motor controller reduces the power steering assist value according to the attenuation curve. Once the second motor controller fully takes over the power steering function, it enters the rated power steering mode.

[0080] Step 1330: When the first motor controller is in rated assist mode, the second motor controller enters rated assist mode.

[0081] Under normal circumstances, that is, when there is no fault, both the first motor controller and the second motor controller are in rated assist mode.

[0082] When the first motor controller malfunctions, its operating mode changes, resulting in a change in the output assist of the first motor controller. Consequently, the output assist of the second motor controller needs to be adjusted.

[0083] In this embodiment, the first motor controller and the second motor controller communicate using two CAN (Controller Area Network) signals, including a public CAN and a private CAN. The public CAN is used to transmit communication protocol content confirmed with the OEM. The private CAN is used to transmit the fault status of the two motor controllers.

[0084] The public CAN bus interacts with other vehicle systems, such as the body domain controller and the autonomous driving domain controller. The private CAN bus, however, is a direct communication channel between the two motor controllers and does not communicate with any other vehicle nodes. This isolation ensures the real-time and reliable transmission of critical safety information, preventing it from being blocked or interfered with by other less important vehicle communications. Information on the private CAN bus (such as fault status and torque commands) is safety-critical and requires millisecond or even microsecond-level responses. The public CAN bus may transmit a large amount of vehicle information (such as multimedia and door status); if mixed on a single network, safety-critical information may be delayed. This separation design ensures deterministic secure communication.

[0085] The first and second motor controllers use independent power supplies and independent vehicle signals. Allowing the two motor controllers to operate independently ensures that both can output power assistance under normal conditions, and also ensures that a failure in one motor controller will not affect the output of the other, thus improving safety.

[0086] This embodiment introduces a steering gear, including a processor and a memory. The memory stores programs or instructions that can be executed by the processor. When the program or instructions are executed by the processor, they implement the steps of a dual-motor steering gear cooperative control method according to any embodiment of the present invention.

[0087] While specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention.

[0088] Those skilled in the art will recognize that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0089] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and equipment can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0090] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0091] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0092] In addition, the functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0093] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0094] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0095] It should be understood that the sequence numbers of the steps in the invention's content and embodiments do not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The foregoing description of embodiments of this disclosure has been provided for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this disclosure to the exact form disclosed. Various modifications and variations may exist based on the foregoing teachings, or various modifications and variations may be derived from the practice of this disclosure. These embodiments were chosen and described to illustrate the principles of this disclosure and its practical application, so that those skilled in the art can utilize this disclosure in various implementations and modifications suitable for the specific purpose of the concept.

Claims

1. A dual-motor steering gear cooperative control method, characterized by, The dual-motor steering gear comprises a first motor controller and a second motor controller, and the method comprises: acquiring a fault signal of the first motor controller; determining a working mode of the first motor controller according to the fault signal of the first motor controller; determining a working mode of the second motor controller according to the working mode of the first motor controller; wherein the working mode of the motor controller comprises a rated assist mode, an assist degradation mode, a no-assist mode and an assist overload mode, in the rated assist mode, the motor controller outputs assist force according to a calibration parameter, in the assist degradation mode, the motor controller reduces the output assist force value of the motor according to a decay curve, in the no-assist mode, the motor controller does not output assist force, and in the assist overload mode, the assist force value output by the motor controller exceeds the assist force value output by the motor controller in the rated assist mode by a preset proportion; the determination of the working mode of the first motor controller according to the fault signal of the first motor controller comprises: determining a fault state of the first motor controller according to the fault signal of the first motor controller; determining the working mode of the first motor controller according to the fault state of the first motor controller; the fault state comprises a no-fault state, an entering-fault-diagnosis-range non-confirmed-fault state, a fault-confirmed state and an entering-normal-signal-range fault-non-eliminated state; the determination of the working mode of the first motor controller according to the fault state of the first motor controller comprises: in the case that the fault state of the first motor controller is the no-fault state, determining that the working mode of the first motor controller is the rated assist mode; in the case that the fault state of the first motor controller is the entering-fault-diagnosis-range non-confirmed-fault state, determining that the working mode of the first motor controller is the assist degradation mode; in the case that the fault state of the first motor controller is the fault-confirmed state or the entering-normal-signal-range fault-non-eliminated state, determining that the working mode of the first motor controller is the no-assist mode.

2. The method of claim 1, wherein, the fault signal comprises a torque sensor fault signal, an angle sensor fault signal and a motor drive circuit fault signal.

3. The method of claim 2, wherein, the determination of the fault state of the first motor controller according to the fault signal of the first motor controller comprises: determining a fault level of each fault signal; determining the fault state of the first motor controller according to the highest fault level.

4. The method of claim 1, wherein, the determination of the working mode of the second motor controller according to the working mode of the first motor controller comprises: in the case that the working mode of the first motor controller is the no-assist mode, the second motor controller enters the assist overload mode; in the case that the working mode of the first motor controller is the assist degradation mode, the second motor controller enters the assist overload mode, and in the assist overload mode, the second motor controller enters the rated assist mode after satisfying a preset condition; In the case that the working mode of the first motor controller is the rated power assisting mode, the second motor controller enters the rated power assisting mode.

5. The method of claim 1, wherein, The first motor controller and the second motor controller exchange information by two-way CAN signals, including public CAN and private CAN; The public CAN is used to transmit the communication protocol content confirmed by the host factory; The private CAN is used to transmit the fault status of the two-way motor controllers.

6. The method of claim 1, wherein, The first motor controller and the second motor controller adopt independent power supply and independent vehicle signals.

7. A diverter characterized by, A processor and a memory, the memory stores programs or instructions which can be executed by the processor, and the programs or instructions are executed by the processor to realize the steps of the double-motor steering gear cooperative control method in any one of claims 1-6.

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