Master-slave type dual-motor steering gear

Abstract

Compared with a traditional single-motor steering gear, the master-slave type double-motor steering gear is more reliable in structure, double assistance is provided, the steering assistance range is greatly enlarged, and the driving experience is improved; the power-assisted range of a single motor cannot meet the power-assisted requirement, double power-assisted can be provided by using a double-motor steering gear, and the requirement for power-assisted steering of a large-tonnage vehicle is met. In addition, the dual-motor steering gear provides backup schemes for the motors and the controller, at least half of assistance can be provided under the condition that one motor or controller breaks down, the situation that a vehicle cannot steer is avoided, the stability and reliability of the vehicle are improved, and the dual-motor steering gear is suitable for large-scale industrial use and popularization.

Description

Technical Field

[0001] The present invention belongs to the field of commercial vehicle steering systems, and particularly relates to a master-slave dual-motor steering gear. Background Art

[0002] With the development of vehicle intelligence and steering technology, the requirements for driving comfort and safety are getting higher and higher, which requires the steering gear to increase steering torque, functional safety, and redundant design.

[0003] The steering gears in the prior art usually still use single-motor steering gears. Although this setting method can complete power steering, the steering gear itself is a component with high safety requirements. If the steering gear fails during vehicle driving, resulting in the disappearance of power steering, there will be serious potential safety hazards. In addition, the power assistance effect of a single steering gear is also relatively insufficient.

[0004] Generally speaking, the steering gears in the prior art generally have problems of insufficient power assistance effect and stability. Summary of the Invention

[0005] The purpose of the present invention is to provide a master-slave dual-motor steering gear to solve the problems of insufficient power assistance effect and stability of the steering gears in the prior art.

[0006] To solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0007] A master-slave dual-motor steering gear includes sensors, a first controller, a second controller, and corresponding first and second motors. The first controller and the second controller are respectively connected to the vehicle's integrated power supply and vehicle control unit of the vehicle they are in; the first motor and the second motor are connected to the steering wheel of the vehicle they are in;

[0008] The first controller is connected to the second controller, and the first controller and the second controller are respectively connected to the first motor and the second motor;

[0009] The sensors are arranged at the steering wheel of the vehicle, and the sensors are respectively connected to the first controller and the second controller; the sensors are used to detect the angle information and torque information of the steering wheel, and transmit the detected angle and torque information to the first controller and the second controller respectively;

[0010] The first controller and the second controller are used for:

[0011] Determine the real-time angle and real-time torque according to the received angle information and torque information;

[0012] Determine the required power assistance torque of the steering wheel;

[0013] Allocate assist torque so that the first motor and the second motor output corresponding torques to the steering wheel respectively;

[0014] Take corresponding treatment measures according to different fault types.

[0015] The present invention also has the following features:

[0016] Further, the sensor adopts a dual-channel TAS sensor.

[0017] Further, the first controller and the second controller communicate through CAN2 private messages. The message IDs of the first controller and the second controller are different, the signal position definitions and parsing formats are the same, and the communication cycle is 5 ms.

[0018] Further, the first controller and the second controller respectively use the cursor algorithm to convert the angle information transmitted by the dual-channel TAS sensor into an angle signal; and use the angle signal as an initial value to determine the real-time angle;

[0019] Use the following formula to convert the torque information transmitted by the dual-channel TAS sensor into real-time torque:

[0020] T q = k * (TS 1 - TS 2 ) / 2

[0021] where, T q represents the real-time torque;

[0022] TS 1 and TS 2 respectively represent the PWM torque signals for the left turn and the right turn of the steering wheel, that is, the torque information transmitted by the dual-channel TAS sensor;

[0023] k represents the deformation coefficient of the steering wheel torsion bar.

[0024] Further, use the following formula to calculate the assist torque:

[0025] Assist torque = (basic assist torque - return torque - damping torque + friction torque compensation + inertia torque compensation) / transmission ratio.

[0026] Further, use the following steps to calculate the basic assist torque:

[0027] Step a1, the first controller and the second controller respectively perform frequency separation on the real-time torque to obtain a high-frequency part and a low-frequency part;

[0028] Step a2, according to the results obtained in step a1, calculate the high-frequency assist torque and the low-frequency assist torque, and use the sum of the high-frequency assist torque and the low-frequency assist torque as the intermediate assist torque;

[0029] Step a3: Calculate the filter poles ATFLfPole using one-dimensional table interpolation, and determine the compensation filter factors CFlt1 and CFlt2;

[0030] Step a4: Use the following formula to calculate the compensation coefficients A 0 , A 1 and A 2 corresponding to the low frequency, medium frequency, and high frequency of the intermediate assist torque respectively:

[0031] A x = (A x _Slope × ATFLfPole) + A x _Bias

[0032] where, A x represents any one of the compensation coefficients;

[0033] A x _Slope represents the ratio of the selected compensation coefficient;

[0034] A x _Bias represents the bias of the selected compensation coefficient;

[0035] Step a5: According to the three compensation coefficients obtained in step a4, use the following formula to calculate the basic assist torque:

[0036] CFResult = (AssitTorq × A 0 + CFIt1 × A 1 + CFIt2 × A 2 )

[0037] where, CFResult represents the basic assist torque.

[0038] Furthermore, both the first controller and the second controller include a torque coordination module;

[0039] The first controller and the second controller distribute the assist torque according to the actual torque requirements of the first motor and the second motor through the torque coordination module.

[0040] Furthermore, the control identifiers of the first controller and the second controller are different;

[0041] The first controller and the second controller can mutually convert the master-slave control relationship.

[0042] Furthermore, the different fault types include the first controller fault, the second controller fault, and the common fault of both controllers;

[0043] The first controller described above is the main controller, and the second controller is the slave controller;

[0044] The faults of the first controller include: vehicle message loss, steering wheel information loss, first motor fault, and second controller loss;

[0045] The corresponding handling measures when the above-mentioned faults occur in the first controller are as follows:

[0046] The second controller switches to the main controller;

[0047] The second controller switches to the main controller;

[0048] The first controller disconnects, and the second controller controls the second motor to provide assist torque;

[0049] The first controller controls the first motor to output half of the assist torque, and the demand torque of the second motor is 0;

[0050] The faults of the second controller include: vehicle message loss, steering wheel information loss, second motor fault, and first controller loss;

[0051] The corresponding handling measures when the above-mentioned faults occur in the second controller include:

[0052] Do not handle;

[0053] Do not handle;

[0054] The second controller disconnects, and the first motor controls the first motor to provide assist torque;

[0055] The second controller switches to the main controller and controls the second motor to output half of the assist torque, and the demand torque of the first motor is 0;

[0056] The common faults of the dual controllers include: vehicle message loss, steering wheel information loss, and common fault of the dual motor steering gear;

[0057] The corresponding handling measures when the common faults of the dual controllers occur include:

[0058] The first controller and the second controller jointly provide a fixed assist that can ensure the minimum steering function of the vehicle;

[0059] The first controller and the second controller jointly provide a fixed assist that can ensure the minimum steering function of the vehicle;

[0060] Disconnect the first motor and the second motor, and do not output torque.

[0061] Compared with the prior art, the present invention has the following technical effects:

[0062] Compared with the traditional single-motor steering gear, the master-slave dual-motor steering gear of the present invention has a more reliable structure, provides double boost, greatly increases the steering boost range, and improves the driving experience. As the vehicle tonnage and load increase, the required steering boost also becomes larger. The boost range of a single motor can no longer meet the boost requirements. Using a dual-motor steering gear can provide double boost, solving the need for steering boost for large-tonnage vehicles.

[0063] In addition, the dual-motor steering gear of the present invention provides backup solutions for both the motor and the controller. In the case of a failure of one motor or controller, at least half of the boost can still be provided, preventing the vehicle from being unable to steer and improving the stability and reliability of the vehicle, making it suitable for large-scale industrial use and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is the control block diagram of the master-slave dual-motor steering gear of the present invention;

[0065] Figure 2 is the master-slave controller conversion logic diagram of the master-slave dual-motor steering gear of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0066] It should be noted that all components in the present invention, unless otherwise specified, are all components known in the prior art. For example, the vehicle power supply, vehicle control unit, controller, and motor steering gear are all units or devices known to exist in the prior art.

[0067] All methods in the present invention, unless otherwise specified, are methods known in the prior art or content that those skilled in the art can directly obtain based on existing knowledge. For example, CAN communication is known in the prior art, and the torque coordination module is a module that those skilled in the art can implement.

[0068] The following gives specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solution of the present application fall within the protection scope of the present invention.

[0069] A master-slave dual-motor steering gear, including a vehicle, the vehicle includes a vehicle power supply and a vehicle control unit, characterized in that a first controller and a second controller and corresponding first and second motors are provided inside the vehicle;

[0070] The first controller is the master controller, and the second controller is the slave controller;

[0071] The first controller and the second controller are respectively connected to the vehicle power supply and the vehicle control unit of the vehicle where they are located;

[0072] The first controller is connected to the second controller, and the first controller and the second controller are respectively connected to the first motor and the second motor;

[0073] A sensor is provided at the steering wheel of the vehicle, and the sensor is respectively connected to the first controller and the second controller;

[0074] The sensor is used to detect the angle information and torque information of the steering wheel, and transmits the detected angle and torque information to the first controller and the second controller respectively;

[0075] The first controller and the second controller are used for:

[0076] Determine the real-time angle and real-time torque according to the received angle information and torque information;

[0077] Determine the assist torque required by the steering wheel according to the real-time torque data;

[0078] Allocate the assist torque so that the first motor and the second motor respectively output corresponding torques to the steering wheel;

[0079] Take corresponding handling measures according to different fault types.

[0080] As a preferred solution, the sensor uses a dual-channel TAS sensor.

[0081] During actual operation, the angle and hand torque of the steering wheel are input into the first controller and the second controller through the dual-channel TAS sensor. Each channel of the dual-channel TAS sensor is independently powered, and each channel provides an independent torque signal and rotation angle signal. If one channel has a problem, the other channel can still work independently without mutual influence.

[0082] As a preferred solution, the first controller and the second controller communicate through CAN2 private messages to exchange torque control and fault information; the message IDs of the first controller and the second controller are different, the signal position definitions and parsing formats are the same, and the communication cycle is 5 ms to ensure that the signals are not delayed.

[0083] The following gives the main information:

[0084] 1. Master-slave controller identification: The master controller is 1, and the slave controller is 0.

[0085] 2. Torque and motor control interface: Request torque, system ready.

[0086] 3. Fault information: Motor fault, sensor fault, motor angle fault, controller lost.

[0087] In order to realize the redundant design of master-slave controllers and the master-slave switching function and ensure the safety of the system, the slave controller serves as a partial backup of the master controller and can replace the master controller to perform functions under certain conditions. Therefore, most of the software functions of the master and slave controllers are the same.

[0088] However, the master and slave controllers share a calibration and flashing CAN line and need to communicate with each other to exchange information. There are also differences between active control motors and passive control motors, and the software of the master and slave controllers cannot be exactly the same. Specifically, the software of the master and slave controllers has the following differences:

[0089] 1. Different master-slave identification: The master-slave identification is the unique identification of the master and slave controllers. It not only needs to be sent from the interactive message to identify its own master-slave positioning, but also is the identification of the source of the motor demand torque inside the controller software. The motor demand torque of the master controller comes from the calculation of the torque module and the allocated torque of the torque coordination module, and the motor demand torque of the slave controller comes from the torque request received from the interactive message of the master controller. The master-slave controller switch only switches the master-slave identification.

[0090] 2. The master-slave interaction message IDs are different: The master and slave controllers exchange messages on a CAN line, which inevitably requires different message IDs on the CAN line. The underlying software configuration of the master and slave controllers' receiving and sending IDs is opposite, that is, controller A sends id1 and receives id2, controller B sends id2 and receives id1. The interaction ID is only related to the default master-slave controller and does not change with the master-slave controller switch.

[0091] 3. The target addresses of the physical addressing messages of the diagnostic protocol are different, and the response source addresses are different: the master and slave controller software are flashed separately, and the diagnostic request and response message IDs are different to ensure correct flashing, and there will be no mistakes in the master and slave software flashing; the diagnostic tool can also read the diagnostic information, software versions, etc. of the master and slave controllers separately. The diagnostic ID does not change with the switching of the master and slave controllers.

[0092] 4. Different calibration protocol IDs: The master and slave controllers can be calibrated separately to avoid ID conflicts on a CAN line, which will not switch with the master-slave switch.

[0093] Specifically, the dual-channel TAS sensor design itself defines a fixed relationship between the two angle signals output by the sensor under normal working conditions, and calculates the angle by taking the combined relationship of the large angle signal and the small angle signal. The cursor algorithm is a known algorithm in the prior art, and the two signals can be converted into angle signals through the cursor algorithm.

[0094] When the steering wheel speed is fast, the angle calculated by the cursor algorithm is used as the initial value, the periodic changes of the small angle signal are collected, and the real-time angle is calculated accordingly.

[0095] As a further explanation of the dual-channel TAS sensor, the dual-channel TAS sensor sends two PWM angle signals, and the duty cycle increases from 12.5% to 87.5% cyclically as the steering wheel rotates. Among them, the small-angle signal cycles every 40 degrees, and the large-angle signal cycles every 296 degrees. The least common multiple of the two cycles, 1480, is the maximum angle that the dual-channel TAS sensor can measure, with 740 degrees on each side.

[0096] Furthermore, since the angle magnetic ring of the dual-channel TAS sensor can be rotated arbitrarily during installation, the zero angle of the steering wheel may be any angle of this original angle signal. After the steering system is installed, it is necessary to self-learn the angle of the vehicle driving straight as the zero angle. This part of the content is only for further explanation of the usage scenario of the dual-channel TAS sensor and does not fall within the scope of discussion of this embodiment. Those skilled in the art are capable of implementing the above content, and thus it will not be elaborated here.

[0097] The first controller and the second controller use the cursor algorithm to convert the angle information transmitted by the dual-channel TAS sensor into an angle signal; taking the angle signal as the initial value, the real-time angle is determined;

[0098] Using the following formula, the torque information transmitted by the dual-channel TAS sensor is converted into real-time torque:

[0099] T q = k*(TS 1 -TS 2 ) / 2

[0100] where T q represents the real-time torque;

[0101] TS 1 and TS 2 respectively represent the PWM torque signals of the steering wheel turning left and right, that is, the angle information transmitted by the dual-channel TAS sensor;

[0102] k represents the deformation coefficient of the steering wheel torsion bar, and this coefficient can be directly obtained.

[0103] Among them, the steering wheel torque is expressed as the PWM torque signals of two-way difference. When the signals are both 50%, the torsion bar is in the unloaded and relaxed state, that is, zero torque. When the steering wheel turns left, TS 1 i.e., the duty cycle increases, and TS 2 the duty cycle decreases.

[0104] Furthermore, the assist torque includes basic assist torque, return torque, damping torque, friction torque compensation, and inertia torque compensation;

[0105] The following method is used to calculate the assist torque:

[0106] Assist torque = (basic assist torque - return torque - damping torque + friction torque compensation + inertia torque compensation) / transmission ratio.

[0107] Among them, the return torque, damping torque, friction torque compensation, and inertia torque compensation can all be directly obtained by those skilled in the art, or can be obtained by known methods in the art in combination with the actual conditions of the vehicle and road conditions. The following briefly describes the principles of the return torque, damping torque, friction torque compensation, and inertia torque compensation.

[0108] Return torque: The greater the absolute value of the steering wheel angular displacement, the greater the initial value of the return torque; the higher the vehicle speed, the smaller the initial value of the return torque. Using the absolute value of the steering wheel hand torque and the absolute value of the steering wheel angular velocity as inputs, interpolate to calculate the return torque coefficient. The final return torque = initial return torque × return torque coefficient × steering wheel angular displacement sign. The initial return torque, return torque coefficient, and steering wheel angular displacement sign can all be directly obtained by those skilled in the art, or can be obtained by known methods in the art in combination with the actual conditions of the vehicle and road conditions

[0109] Damping torque: Prevent the steering wheel from shaking at high vehicle speeds. The greater the absolute value of the steering wheel angular velocity, the greater the absolute value of the damping torque; the higher the vehicle speed, the greater the absolute value of the damping torque.

[0110] Friction torque compensation: The friction compensation torque is equal to the initial friction compensation torque multiplied by the friction compensation torque coefficient. Perform a first-order low-pass filter on the input motor speed. The greater the absolute value of the low-frequency part of the motor speed, the greater the initial value of the friction compensation torque. The friction compensation torque coefficient is calculated by interpolation according to the vehicle speed.

[0111] Inertia torque compensation: The inertia compensation torque is equal to the initial inertia compensation torque multiplied by the inertia compensation torque coefficient. First, calculate the change rate of the motor speed, and perform one-dimensional table interpolation according to the change rate of the motor speed to calculate the initial value of the inertia compensation torque. The inertia compensation torque coefficient is calculated according to the vehicle speed.

[0112] Furthermore, perform frequency separation on the real-time torque. The low-frequency part reflects the actual hand torque of the driver and is used to calculate the basic assist torque. The high-frequency part reflects the road surface excitation and will cause the phase to lead, which is used to maintain the road feel and improve the sensitivity of the assist. The higher the vehicle speed, the smaller the high-frequency and low-frequency assist torques; the greater the absolute value of the high-frequency and low-frequency hand torques of the steering wheel, the greater the high-frequency and low-frequency assist torques. Add the calculated high-frequency assist torque and low-frequency assist torque to obtain the intermediate assist torque.

[0113] Among them, those skilled in the art know the specific ranges defined by "high frequency" and "low frequency". In addition, those skilled in the art can also limit the frequency ranges of high frequency and low frequency by known methods according to the actual conditions of the vehicle and road conditions. The same applies to "low frequency, medium frequency, and high frequency" in the following text.

[0114] Calculate the basic assist torque using the following steps:

[0115] Step a1, the first controller and the second controller respectively perform frequency separation on the real-time torque to obtain the high-frequency part and the low-frequency part;

[0116] Step a2, calculate the high-frequency assist torque and the low-frequency assist torque, and take the sum of the high-frequency assist torque and the low-frequency assist torque as the intermediate assist torque;

[0117] Step a3, use one-dimensional table interpolation to calculate the filter pole ATFLfPole, and determine the compensation filter factors CFlt1 and CFlt2;

[0118] Step a4, use the following formula to calculate the compensation coefficients A 0 , A 1 and A 2 corresponding to the low-frequency, intermediate-frequency, and high-frequency of the intermediate assist torque respectively:

[0119] A x =(A x _Slope×ATFLfPole)+A x _Bias

[0120] where A x represents any one of the compensation coefficients;

[0121] A x _Slope represents the ratio of the selected compensation coefficient and can be directly obtained;

[0122] A x _Bias represents the bias of the selected compensation coefficient and can be directly obtained;

[0123] Step a5, according to the three compensation coefficients, use the following formula to calculate the basic assist torque:

[0124] CFResult=(AssitTorq×A 0 +CFIt1×A 1 +CFIt2×A 2 )

[0125] where CFResult represents the basic assist torque.

[0126] Furthermore, both the first controller and the second controller include a torque coordination module; the control block diagram of the master-slave dual-motor steering gear is as Figure 1 shown.

[0127] The first controller and the second controller distribute the assist torque according to the actual torque requirements of the first motor and the second motor through the torque coordination module.

[0128] Furthermore, the control software built into the first controller and the second controller is the same, but the control identifiers are different; for fault information, the master and slave controllers can be switched, that is, the slave controller is switched to the master controller, and the master controller is switched to the slave controller.

[0129] The slave controller acts as the master controller to calculate the system demand torque for torque distribution.

[0130] Specifically, different fault types include the first controller fault, the second controller fault, and the common fault of the dual controllers;

[0131] The first controller fault includes: loss of vehicle messages, loss of steering wheel information, first motor fault, and loss of the second controller;

[0132] The corresponding handling measures when the first controller has the above faults include:

[0133] The second controller switches to the master controller;

[0134] The second controller switches to the master controller;

[0135] The first controller is disconnected, and the second motor provides the assist torque;

[0136] The first controller controls the first motor to output half of the assist torque, and the demand torque of the second motor is 0;

[0137] The second controller fault includes: loss of vehicle messages, loss of steering wheel information, second motor fault, and loss of the first controller;

[0138] The corresponding handling measures when the second controller has the above faults include:

[0139] Do not process;

[0140] Do not process;

[0141] The second controller is disconnected, and the first motor controls the first motor to provide the assist torque;

[0142] The second controller switches to the master controller and controls the second motor to output half of the assist torque, and the demand torque of the first motor is 0;

[0143] The common fault of the dual controllers includes: loss of vehicle messages, loss of steering wheel information, and common fault of the dual motor steering gear;

[0144] The corresponding handling measures when the common fault of the dual controllers occurs include:

[0145] The first controller and the second controller jointly provide a fixed assist that can ensure the minimum steering function of the vehicle;

[0146] The first controller and the second controller jointly provide a fixed boost that can ensure the minimum steering function of the vehicle;

[0147] Disconnect the first motor and the first motor, and do not output torque.

[0148] For further convenience of understanding, this embodiment gives the fault information comparison table 1:

[0149]

[0150] Table 1 Fault Information Comparison Table

[0151] Among them, the "fixed boost for the minimum steering function of the vehicle" is the content that those skilled in the art can directly obtain according to different vehicle conditions, which does not fall within the scope of discussion of this embodiment and will not be elaborated here.

[0152] The following combines Figure 2 Describe the conversion logic of the main control controller. When a fault occurs and the master and slave controllers need to be converted with each other, the conversion logic is as follows:

[0153] By default, the A controller is the master controller and the B controller is the slave controller.

[0154] When the communication between the A and B controllers is normal, if there are problems with the vehicle information and steering wheel information received by the A controller, the A controller is converted into the slave controller and the B controller is converted into the master controller;

[0155] When the A and B cannot communicate normally, both the A and B are master controllers and control their respective motors to work.

[0156] The master-slave dual-motor cooperative control of this embodiment has the following advantages:

[0157] Compared with the traditional single-motor steering gear, the master-slave dual-motor steering gear has a more complex structure, with one more motor and controller added, the cost has increased, and the cooperative control is more complex than the original one-to-one control method of the controller and the motor.

[0158] After using the method proposed in this embodiment to solve the problem of cooperative control, the master-slave dual-motor steering gear solves the technical problems that the single-motor steering gear cannot solve and demonstrates its unique advantages, mainly including the following two points:

[0159] Provide double boost, greatly increase the steering boost range, and improve the driving experience: As the vehicle tonnage and load increase, the boost required for steering becomes greater and greater. The boost range of a single motor can no longer meet the boost requirements. Using a dual-motor steering gear can provide double boost, solve the demand for steering boost of large-tonnage vehicles, and improve the driving experience.

[0160] Need for functional safety: Once a motor or controller fails in a single-motor steering gear, it cannot provide power steering. Since the steering gear is a safety component of the vehicle, this can cause the vehicle to become inoperable. In contrast, a dual-motor steering gear provides a backup solution for both the motor and the controller. In the event of a failure of one motor or controller, it can still provide at least half of the power assistance, preventing the vehicle from losing its ability to steer and enhancing the safety and reliability of the vehicle.

[0161] In addition, a cooperative control module is added on the basis of the control of the traditional single-motor steering gear. The cooperative control module includes functions such as master-slave identification conversion, torque distribution, message control, fault classification, and safety response handling. The underlying software changes the communication, diagnostic, and calibration message IDs of the slave controller to distinguish them from those of the master controller. This enables the management and control of the dual-motor steering gear, allowing the two motors to work together to achieve the power steering function, enhancing the steering ability and safety reliability of the steering component. It has been applied in the software development process of the master-slave dual-motor steering gear and has passed the tests on the prototype vehicle.

Claims

1. A master-slave dual-motor steering gear, characterized in that: It includes a sensor, a first controller, a second controller, and corresponding first and second motors, wherein the first and second controllers are respectively connected to a vehicle power supply and a vehicle control unit of the vehicle in which they are located; the first and second motors are connected to the steering wheels of the vehicles in which they are located; The first controller is connected to the second controller, and the first controller and the second controller are connected to the first motor and the second motor respectively; The sensor is arranged at the steering wheel of the vehicle, and the sensor is connected to the first controller and the second controller respectively; the sensor is used to detect the angle information and torque information of the steering wheel, and transmit the detected angle and torque information to the first controller and the second controller respectively; The first controller and the second controller are used for: Determine the real-time angle and the real-time torque according to the received angle information and torque information; Determine the steering wheel assist torque required; Distributing the assist torque so that the first motor and the second motor respectively output corresponding torques to the steering wheel; Take corresponding measures according to different fault types.

2. The master-slave dual-motor steering gear according to claim 1 is characterized in that: The sensor adopts a dual-path TAS sensor.

3. The master-slave dual-motor steering gear according to claim 2, characterized in that: The first controller and the second controller communicate with each other via CAN2 private messages. The message IDs of the first controller and the second controller are different, the signal position definition and parsing format are the same, and the communication cycle is 5ms.

4. The master-slave dual-motor steering gear according to claim 2, characterized in that: The first controller and the second controller respectively use a cursor algorithm to convert the angle information transmitted by the dual-path TAS sensor into an angle signal; and use the angle signal as an initial value to determine the real-time angle; Use the following formula to convert the torque information transmitted by the dual-path TAS sensor into real-time torque: T q =k*(TS1-TS2) / 2 Among them, T q Indicates real-time torque; TS1 and TS2 represent the PWM torque signals for left and right steering wheel turns, respectively, i.e., the torque information transmitted by the dual-channel TAS sensors; k represents the deformation coefficient of the steering wheel torsion bar.

5. The master-slave dual-motor steering gear according to claim 4, characterized in that: The assist torque is calculated using the following formula: Assist torque = (basic assist torque - return torque - damping torque + friction torque compensation + inertia torque compensation) / transmission ratio.

6. The master-slave dual-motor steering gear according to claim 5, characterized in that: Use the following steps to calculate the base assist torque: Step a1, the first controller and the second controller perform frequency separation on the real-time torque to obtain a high-frequency part and a low-frequency part; Step a2, according to the result obtained in step a1, the high-frequency assist torque and the low-frequency assist torque are calculated, and the sum of the high-frequency assist torque and the low-frequency assist torque is used as the intermediate assist torque; Step a3, using a one-dimensional table to interpolate and calculate the filter pole ATFLfPole, and determining the compensation filter factor CFlt1 and the factor CFlt2; Step a4, using the following formula, calculate the compensation coefficients A0, A1 and A2 corresponding to the low frequency, medium frequency and high frequency of the intermediate assist torque respectively: THE x =(A x _Slope×ATFLfPole)+A x _Bias Among them, A x represents any compensation coefficient; A x _Slope represents the ratio of the selected compensation coefficient; A x _Bias represents the bias of the selected compensation coefficient; Step a5, according to the three compensation coefficients obtained in step a4, use the following formula to calculate the basic assist torque: CFResult=(AssitTorq×A0+CFIt1×A1+CFIt2×A2) Among them, CFResult represents the basic assist torque.

7. The master-slave dual-motor steering gear according to claim 6, characterized in that: The first controller and the second controller both include a torque coordination module; The first controller and the second controller distribute the assist torque according to the actual torque requirements of the first motor and the second motor through the torque coordination module.

8. The master-slave dual-motor steering gear according to claim 7, characterized in that: The control identifiers of the first controller and the second controller are different; The first controller and the second controller can switch between master-slave control relationships.

9. The master-slave dual-motor steering gear according to claim 8, characterized in that: The different fault types include first controller fault, second controller fault and dual controller common fault; The first controller is a master controller, and the second controller is a slave controller; The first controller failure includes: vehicle message loss, steering wheel information loss, first motor failure and second controller loss; When the first controller has the above faults, the corresponding processing measures are as follows: The second controller switches to the main controller; The second controller switches to the main controller; The first controller is disconnected, and the second controller controls the second motor to provide assist torque; The first controller controls the first motor to output half of the assist torque, and the required torque of the second motor is 0; The second controller failure includes: vehicle message loss, steering wheel information loss, second motor failure and first controller loss; When the second controller has the above faults, the corresponding processing measures include: No treatment; No treatment; The second controller is disconnected, and the first motor is controlled by the first motor to provide assist torque; The second controller switches to the main controller, controls the second motor to output half of the assist torque, and the required torque of the first motor is 0; The common faults of the dual controllers include: vehicle message loss, steering wheel information loss and dual motor steering gear common faults; The one-to-one corresponding processing measures when a common failure of the dual controllers occurs include: The first controller and the second controller jointly provide a fixed power assist capable of ensuring a minimum steering function of the vehicle; The first controller and the second controller jointly provide a fixed power assist capable of ensuring a minimum steering function of the vehicle; The first motor and the second motor are disconnected and no torque is output.

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