Integrated system of vehicle redundant steer-by-wire and auxiliary drive and control method thereof

Abstract

The application provides a kind of vehicle redundant steer-by-wire steering and auxiliary drive integrated system and its control method, including steering mechanism, drive mechanism, steer-by-wire motor, auxiliary motor, first electromagnetic clutch, second electromagnetic clutch, energy storage mechanism, VCU, detection mechanism and steering shaft;The VCU is connected with steer-by-wire motor, auxiliary motor, drive motor, first electromagnetic clutch, second electromagnetic clutch and detection mechanism respectively, and the VCU monitors the running state of steer-by-wire motor and the driving torque demand Tr in real time, controls the connection or disconnection of first electromagnetic clutch and second electromagnetic clutch, to realize the switching of working mode.The application integrates steer-by-wire steering and drive system, and uses the coupling mode switching of auxiliary motor and electromagnetic clutch, solves the safety problem of traditional steer-by-wire steering system when steer-by-wire motor fails, can realize more safe and efficient vehicle steering and driving, and at the same time improves the energy utilization efficiency of vehicle under different working conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of redundant steer-by-wire and auxiliary drive integrated system, and particularly relates to a vehicle redundant steer-by-wire and auxiliary drive integrated system and a control method thereof. BACKGROUND

[0002] Traditional automobile steering systems usually use mechanical hydraulic assistance or full electronic assistance to achieve steering. However, with the development of electric vehicles and hybrid vehicles, the requirements for energy utilization efficiency and safety of vehicles are becoming higher and higher. Although the traditional steer-by-wire system can achieve precise steering control, when the steer-by-wire motor fails, it may cause the vehicle to lose steering ability, thereby endangering driving safety.

[0003] In addition, with the advancement of electric vehicle technology, how to improve energy utilization efficiency while ensuring vehicle power performance has become an important issue. During the braking and coasting process of the vehicle, the braking energy is converted into electrical energy and stored by the energy recovery system, which can effectively improve the cruising range of the vehicle. However, the existing energy recovery system still has some limitations in practical application, such as low energy recovery efficiency, high system complexity, and other problems. SUMMARY

[0004] In view of the above technical problems, the present application provides a vehicle redundant steer-by-wire and auxiliary drive integrated system and a control method thereof.

[0005] The vehicle redundant steer-by-wire and auxiliary drive integrated system of the present application uses the coupling mode switching of the auxiliary motor and the electromagnetic clutch to solve the safety problem of the traditional steer-by-wire system when the steer-by-wire motor fails, and optimizes the working mode of the drive motor and the auxiliary motor to improve the energy utilization efficiency under different driving conditions. In addition, the system can also realize braking and sliding energy recovery through the auxiliary motor, further improving the comprehensive utilization efficiency of energy.

[0006] Note that the description of these objects does not hinder the existence of other objects. One embodiment of the present application does not need to achieve all the above-mentioned purposes.

[0007] The present application achieves the above technical purposes through the following technical means.

[0008] A vehicle redundant steer-by-wire and auxiliary drive integrated system, comprising a steering mechanism, a drive mechanism, a steer-by-wire motor, an auxiliary motor, a first electromagnetic clutch, a second electromagnetic clutch, an energy storage mechanism, a VCU, a detection mechanism and a steering shaft;

[0009] The steer-by-wire motor is connected to the first steering reducer and the steering mechanism for rotating the wheels;

[0010] The driving mechanism comprises a driving motor, a main transmission shaft and a half shaft, the driving motor is connected with the input end of the main transmission shaft, the output end of the main transmission shaft is connected with the half shaft, and the two ends of the half shaft are respectively connected with the hubs of the two side wheels; the auxiliary motor is connected with the second steering reducer and the steering mechanism, the first electromagnetic clutch is installed between the auxiliary motor and the second steering reducer, and the first electromagnetic clutch is used for controlling the coupling of the auxiliary motor and the steering mechanism; the auxiliary motor is connected with the main transmission shaft through the planetary gear mechanism, the second electromagnetic clutch is installed between the auxiliary motor and the planetary gear mechanism, and the second electromagnetic clutch is used for controlling the coupling of the auxiliary motor and the driving motor;

[0011] The energy storage mechanism is connected with the auxiliary motor and the driving motor respectively;

[0012] The detection mechanism is connected with the output end of the steering shaft, is used for collecting the rotation angle signal and the torque signal, and transmits the rotation angle signal and the torque signal to the VCU, and the input end of the steering shaft is connected with the steering wheel;

[0013] The VCU is connected with the steer-by-wire motor, the auxiliary motor, the driving motor, the first electromagnetic clutch, the second electromagnetic clutch and the detection mechanism respectively, the VCU monitors the running state of the steer-by-wire motor and the driving torque demand Tr in real time, controls the connection or disconnection of the first electromagnetic clutch and the second electromagnetic clutch, and realizes the switching of the working mode.

[0014] In the above scheme, the working mode comprises a redundant safe steering mode, an auxiliary driving mode and an energy recovery mode;

[0015] The VCU monitors the driving torque demand Tr and the self-checking data of the steer-by-wire motor in real time, and processes the data; the VCU judges whether the steer-by-wire motor fails or not;

[0016] If the steer-by-wire motor fails, the redundant safe steering mode is executed, the VCU controls the first electromagnetic clutch to be connected, the second electromagnetic clutch to be disconnected, and the auxiliary motor to execute the electric mode to provide the steering assist;

[0017] If the steer-by-wire motor does not fail, the driving torque demand Tr is determined preliminarily, if Tr>0, the auxiliary driving mode is executed, and if Tr≤0, the energy recovery mode is executed;

[0018] If the auxiliary drive mode is executed, the driving torque demand Tr is determined again, if Tr≤Ta, the uniform speed drive mode is executed, the VCU controls the first electromagnetic clutch to be disconnected, the second electromagnetic clutch to be disconnected, the VCU controls the auxiliary motor to stop working, and the driving motor provides the driving torque alone; if Tr>Ta, the acceleration drive mode is executed, the VCU controls the first electromagnetic clutch to be disconnected, the second electromagnetic clutch to be connected, the auxiliary motor executes the auxiliary drive mode, and the driving motor and the auxiliary motor cooperatively provide the driving torque.

[0019] If the energy recovery mode is executed, the VCU controls the first electromagnetic clutch to be disconnected, the second electromagnetic clutch to be connected, the VCU controls the auxiliary motor to be reversed to provide a reverse torque to realize power generation, and the VCU controls the driving motor to stop working.

[0020] In the above scheme, the driving mechanism further comprises a main reducer and a differential; the output end of the main transmission shaft is connected with the input end of the differential for transmitting the driving torque, and the output end of the differential is connected with the half shaft; and the main reducer is connected with the main transmission shaft.

[0021] In the above scheme, the steering mechanism comprises a trapezoidal arm, a steering tie rod, a first rack and pinion mechanism, and a second rack and pinion mechanism.

[0022] Both ends of the steering tie rod are connected with the trapezoidal arms respectively, and the trapezoidal arms are connected with the half shafts through steering knuckles respectively.

[0023] The steer-by-wire motor is connected with the input end of the first steering reducer and the first rack and pinion mechanism, the output end of the first rack and pinion mechanism is connected with the steering tie rod, the torque of the steer-by-wire motor is transmitted to the steering tie rod for rotating the wheels.

[0024] The auxiliary motor is connected with the input end of the second steering reducer and the second rack and pinion mechanism, the output end of the second rack and pinion mechanism is connected with the steering tie rod, the torque of the auxiliary motor is transmitted to the steering tie rod for rotating the wheels.

[0025] In the above scheme, the sun gear of the planetary gear mechanism is connected with the auxiliary motor, the planetary carrier is fixed, and the outer ring gear of the planetary gear mechanism is connected with the main transmission shaft through gear meshing.

[0026] In the above scheme, the energy storage mechanism comprises an inverter and a power supply; the inverter is arranged between the auxiliary motor and the power supply, the inverter is used for converting the alternating current generated during energy recovery into direct current and storing the direct current in the power supply, and the inverter is also connected with the driving motor for converting the direct current of the power supply into alternating current to supply the driving motor when needed.

[0027] A control method of the integrated system of vehicle redundant steer-by-wire and auxiliary drive, comprising the following steps:

[0028] The VCU monitors the running state of the steer-by-wire motor and the driving torque demand Tr in real time;

[0029] The VCU controls the connection or disconnection of the first electromagnetic clutch and the second electromagnetic clutch according to whether the steer-by-wire motor fails and the driving torque demand Tr to realize the switching of the redundant safe steering mode, the auxiliary drive mode and the energy recovery mode.

[0030] In the above scheme, the redundant safe steering mode comprises the following steps:

[0031] If the VCU judges that the steer-by-wire motor fails, the redundant safe steering mode is executed; the VCU controls the first electromagnetic clutch to be connected and the second electromagnetic clutch to be disconnected, and the auxiliary motor executes the electric mode to provide steering assistance.

[0032] In the above scheme, the auxiliary drive mode comprises the following steps:

[0033] If the VCU judges that the steer-by-wire motor does not fail, the driving torque demand Tr is initially determined, if Tr>0, the auxiliary drive mode is executed, and the driving torque demand Tr is determined again, if Tr≤Ta, the uniform speed drive mode is executed, the VCU controls the first electromagnetic clutch to be disconnected and the second electromagnetic clutch to be disconnected, the VCU controls the auxiliary motor to stop working, and the driving motor alone provides the driving torque; if Tr>Ta, the acceleration drive mode is executed, the VCU controls the first electromagnetic clutch to be disconnected and the second electromagnetic clutch to be connected, the auxiliary motor executes the auxiliary drive mode, and the driving motor and the auxiliary motor cooperatively provide the driving torque.

[0034] In the above scheme, the energy recovery mode comprises the following steps:

[0035] If Tr≤0, the energy recovery mode is executed; if the energy recovery mode is executed, the VCU controls the first electromagnetic clutch to be disconnected and the second electromagnetic clutch to be connected, the VCU controls the auxiliary motor to be reversed to provide a reverse torque to realize power generation, and the VCU controls the driving motor to stop working.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The application integrates steer-by-wire and drive systems, and uses the coupling mode switching of auxiliary motor and electromagnetic clutch to solve the safety problem of traditional steer-by-wire system when the steer-by-wire motor fails, and improve the energy utilization efficiency of the vehicle under different working conditions. When the steer-by-wire motor fails, the system can automatically switch to the redundant mode, and provide steering assistance through the auxiliary motor to ensure that the vehicle still has reliable steering capability. In addition, under different driving conditions, the system can optimize the working mode of the auxiliary motor according to the actual demand, and when additional torque or acceleration is needed, the auxiliary motor and the drive motor work together to improve the driving torque; and when uniform speed driving or low torque demand is needed, the auxiliary motor is out of work, saving energy. During the vehicle braking or coasting process, the system can realize brake energy recovery through the auxiliary motor, and store the brake energy into electric energy, further improving the comprehensive utilization rate of energy. The application can realize more safe and efficient vehicle steering and driving, and is suitable for the application requirements of modern electric vehicles.

[0038] Note that the description of these effects does not preclude the presence of other effects. One embodiment of the present application does not necessarily have all of the effects described above. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a vehicle redundant steer-by-wire and auxiliary drive integrated system structure top view of an embodiment of the application;

[0040] Figure 2 is a vehicle redundant steer-by-wire and auxiliary drive integrated system structure front view of an embodiment of the application;

[0041] Figure 3 is a vehicle redundant steer-by-wire and auxiliary drive integrated system control method control architecture of an embodiment of the application.

[0042] In the figure, 1, wheel; 2, hub; 3, trapezoidal arm; 4, steering tie rod; 5, first electromagnetic clutch; 6, auxiliary motor; 7, second electromagnetic clutch; 8, planetary gear mechanism; 9, inverter; 10, power supply; 11, drive motor; 12, VCU; 13, detection mechanism; 14, steering shaft; 15, steering wheel; 16, main drive shaft; 17, main reducer; 18, steer-by-wire motor; 19, first steering reducer; 20, half shaft; 21, first rack and pinion mechanism; 22, differential; 23, second rack and pinion mechanism; 24, second steering reducer; 25, steering knuckle. DETAILED DESCRIPTION

[0043] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below are exemplary and are intended to explain the present application, and are not to be understood as limiting the present application.

[0044] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "front", "back", "left", "right", "up", "down", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0045] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] Figure 1 and 2 A preferred embodiment of the integrated system of the vehicle redundant steer-by-wire and auxiliary drive according to the present application is shown, which comprises a steering mechanism, a driving mechanism, a steer-by-wire motor 18, an auxiliary motor 6, a first electromagnetic clutch 5, a second electromagnetic clutch 7, an energy storage mechanism, a VCU 12, a detection mechanism 13 and a steering shaft 14;

[0047] The steer-by-wire motor 18 is connected to the steering mechanism through a first steering reducer 19, and is used to rotate the wheel 1;

[0048] The driving mechanism comprises a driving motor 11, a main transmission shaft 16 and a half shaft 20, the driving motor 11 is connected with the input end of the main transmission shaft 16, the output end of the main transmission shaft 16 is connected with the half shaft 20, and the two ends of the half shaft 20 are respectively connected with the hubs 2 of the two side wheels 1;

[0049] The auxiliary motor 6 is connected with the steering mechanism through a second steering speed reducer 24 and a steering mechanism, a first electromagnetic clutch 5 is installed between the auxiliary motor 6 and the second steering speed reducer 24, the first electromagnetic clutch 5 is used for controlling the coupling of the auxiliary motor 6 and the steering mechanism; the auxiliary motor 6 is connected with the main transmission shaft 16 through a planetary gear mechanism 8, and the torque is adjusted through the planetary gear mechanism 8, so that the auxiliary motor 6 and the driving motor 11 cooperatively provide a driving torque in a required working condition, a second electromagnetic clutch 7 is installed between the auxiliary motor 6 and the planetary gear mechanism 8, and the second electromagnetic clutch 7 is used for controlling the coupling of the auxiliary motor 6 and the driving motor 11;

[0050] The energy storage mechanism is connected with the auxiliary motor 6 and the driving motor 11 respectively;

[0051] The detection mechanism 13 is connected with the output end of the steering shaft 14, is used for collecting a steering angle signal and a torque signal, and transmits the signals to the VCU 12, and the input end of the steering shaft 14 is connected with the steering wheel 15;

[0052] The VCU 12 is connected with the steer-by-wire motor 18, the auxiliary motor 6, the driving motor 11, the first electromagnetic clutch 5, the second electromagnetic clutch 7 and the detection mechanism 13 respectively, the VCU 12 monitors the running state of the steer-by-wire motor 18 and the driving torque demand Tr in real time, controls the connection or disconnection of the first electromagnetic clutch 5 and the second electromagnetic clutch 7, and realizes the switching of the working mode.

[0053] The working mode comprises a redundant safe steering mode, an auxiliary driving mode and an energy recovery mode;

[0054] The VCU 12 monitors the driving torque demand Tr and the self-checking data of the steer-by-wire motor 18 in real time, and processes the data; the VCU 12 judges whether the steer-by-wire motor 18 fails;

[0055] If the steer-by-wire motor 18 fails, the redundant safe steering mode is executed, the VCU 12 controls the first electromagnetic clutch 5 to be connected, the second electromagnetic clutch 7 to be disconnected, and the auxiliary motor 6 to execute an electric mode to provide steering assistance;

[0056] If the steer-by-wire motor 18 does not fail, the driving torque demand Tr is preliminarily judged, if Tr>0, the auxiliary driving mode is executed, and if Tr≤0, the energy recovery mode is executed;

[0057] If the auxiliary drive mode is executed, the driving torque demand Tr is determined again, if Tr <= Ta, the uniform speed drive mode is executed, the VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be disconnected, the VCU 12 controls the auxiliary motor 6 to stop working, and the driving motor 11 provides the driving torque alone; if Tr > Ta, the acceleration drive mode is executed, the VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be connected, the auxiliary motor 6 to execute the auxiliary drive mode, and the driving motor 11 and the auxiliary motor 6 cooperatively provide the driving torque;

[0058] If the energy recovery mode is executed, the VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be connected, the VCU 12 controls the auxiliary motor 6 to be reversed to provide a reverse torque to realize power generation, and the VCU 12 controls the driving motor 11 to stop working.

[0059] The steering mechanism comprises a trapezoidal arm 3, a steering tie rod 4, a first gear rack mechanism 21 and a second gear rack mechanism 23; the two ends of the steering tie rod 4 are respectively connected with the trapezoidal arms 3, and the trapezoidal arms 3 are respectively connected with the half shafts 20 through steering knuckles 25; the steer-by-wire motor 18 is connected with the input end of the first steering reducer 19 and the input end of the first gear rack mechanism 21, the output end of the first gear rack mechanism 21 is connected with the steering tie rod 4, the torque of the steer-by-wire motor 18 is transmitted to the steering tie rod 4, and the steering tie rod 4 is used to rotate the wheels 1; the auxiliary motor 6 is connected with the input end of the second steering reducer 24 and the input end of the second gear rack mechanism 23, the output end of the second gear rack mechanism 23 is connected with the steering tie rod 4, the torque of the auxiliary motor 6 is transmitted to the steering tie rod 4, and the steering tie rod 4 is used to rotate the wheels 1.

[0060] The system relies on multiple key components to work together to realize the integrated control of redundant steer-by-wire and auxiliary drive.

[0061] The wheels 1 are the final execution components of the system, which realize the steering and driving of the vehicle after receiving the steering and driving torque. The hub 2 provides a mounting and transmission basis for steering and driving. The trapezoidal arms 3, the steering knuckles 25 and the steering tie rods 4 are mechanical structural components for transmitting the torque generated by steering to the wheels 1. One end of the trapezoidal arm 3 is connected with the steering knuckle 25, and the other end is connected with the trapezoidal arm 3 on the other side of the vehicle through the steering tie rod 4, so as to ensure that the steering torque can be smoothly transmitted to the wheels 1 on both sides.

[0062] The steer-by-wire motor 18 is one of the core components of the system, which is responsible for the output of the steering torque under normal conditions. The steer-by-wire motor 18 transmits the torque to the steering tie rod 4 through the first steering reducer 19 and the first gear rack mechanism 21, and finally rotates the wheels 1.

[0063] The auxiliary motor 6 takes over the steering work when the online control steering motor 18 fails, and cooperates with the drive motor 11 to provide driving torque for the vehicle in some working conditions. In addition, the auxiliary motor 6 also has the function of energy recovery, which converts kinetic energy into electrical energy during coasting or braking.

[0064] The first electromagnetic clutch 5 and the second electromagnetic clutch 7 are respectively used to couple the auxiliary motor 6 with the steering mechanism or the drive mechanism, ensuring that the system can dynamically switch between different modes. Specifically, the first electromagnetic clutch 5 is used to control the coupling of the auxiliary motor 6 with the steering mechanism, and the second electromagnetic clutch 7 is used to control the coupling of the auxiliary motor 6 with the drive mechanism.

[0065] Preferably, the planetary gear mechanism 8 includes a sun gear, a planet gear, a planet carrier, and an outer ring gear. The sun gear is connected with the auxiliary motor 6, the planet carrier is fixed, and the outer ring gear is connected with the main drive shaft 16 through gear meshing. In this way, the output speed and driving torque can be flexibly adjusted.

[0066] The VCU 12 is the central control unit of the entire system, responsible for real-time monitoring of vehicle status and coordinated control of each subsystem. The VCU 12 controls the connection or disconnection of the electromagnetic clutch to realize the switching of different working modes.

[0067] The inverter 9 converts the alternating current generated during energy recovery into direct current and stores it in the power supply 10. Conversely, when needed, it converts the direct current into alternating current to supply the drive motor 11, ensuring efficient and stable electrical energy management of the system.

[0068] The rotor of the drive motor 11 is connected with the input end of the main drive shaft 16, which is used to provide the main driving torque.

[0069] The drive mechanism also includes a main reducer 17 and a differential 22. The output end of the main drive shaft 16 is connected with the input end of the differential 22 for transmitting driving torque, and the output end of the differential 22 is connected with the half shaft 20. The main reducer 17 is connected with the main drive shaft 16, mainly responsible for reducing the speed and increasing the driving torque. The differential 22 allows the wheels 1 to rotate at different speeds when turning, while reasonably distributing the driving torque to the wheels 1 to improve the maneuverability and stability of the vehicle.

[0070] The sun gear of the planetary gear mechanism 8 is connected with the auxiliary motor 6, and the planet carrier is fixed. The outer ring gear of the planetary gear mechanism 8 is connected with the main drive shaft 16 through gear meshing.

[0071] The energy storage mechanism comprises an inverter 9 and a power supply 10; the inverter 9 is arranged between the auxiliary motor 6 and the power supply 10, the inverter 9 is used for converting the alternating current generated during energy recovery into direct current and storing the direct current in the power supply 10, the inverter 9 is also connected with the driving motor 11, and is used for converting the direct current of the power supply 10 into alternating current to supply the driving motor 11 when needed, so as to facilitate ensuring that the power management of the system is efficient and stable, meanwhile, power regulation, frequency and phase synchronization are ensured, and overload and short circuit protection are provided, thereby improving the efficiency of energy recovery and the safety of the system.

[0072] The detection mechanism (13) comprises a rotation angle sensor and a torque sensor, the rotation angle sensor is used for detecting a rotation angle signal of the steering shaft, and the torque sensor is used for detecting a torque signal of the steering shaft.

[0073] The application also provides a control method of the integrated system of vehicle redundant steer-by-wire and auxiliary driving, which can switch multiple working modes according to the electronic device fault condition and driving torque demand, and the working modes and switching principles are as follows:

[0074] (1) The control method of the integrated system of vehicle redundant steer-by-wire and auxiliary driving comprises an overall system control architecture based on control mode switching.

[0075] The overall content of the overall system control architecture based on control mode switching is as follows:

[0076] As shown in Figure 3 The control method of the integrated system of vehicle redundant steer-by-wire and auxiliary driving comprises an overall mode switching control architecture, which covers a redundant safe steering mode, an auxiliary driving mode and an energy recovery mode.

[0077] The integrated system of vehicle redundant steer-by-wire and auxiliary driving is centrally controlled by the VCU 12, the VCU 12 monitors the running state of each subsystem in real time, such as whether the steer-by-wire motor 18 is faulty and the driving torque demand Tr, and selects a suitable running mode according to different working conditions.

[0078] When the steer-by-wire motor 18 is faulty, the VCU 12 gives priority to safety and immediately switches to the redundant safe steering mode, so as to ensure that the vehicle can continue to realize the steering function.

[0079] In the normal steering condition, i.e. the steer-by-wire motor 18 is not faulty, the VCU 12 makes a decision on the auxiliary drive mode or the energy recovery mode according to the actual driving state of the vehicle. After the decision on the auxiliary drive mode or the energy recovery mode is made, the state switching in the form of the electromagnetic clutch connection and disconnection is used, and meanwhile, the dynamic switching between the uniform speed drive mode, the acceleration drive mode and the coasting energy recovery mode, the braking energy recovery mode is realized according to the driving torque demand or the acceleration state of the vehicle.

[0080] Specifically, the control method of the integrated system of the vehicle redundant steer-by-wire and auxiliary drive includes the following steps:

[0081] The VCU 12 monitors the running state of the steer-by-wire motor 18 and the driving torque demand Tr in real time, collects the self-checking data of the steer-by-wire motor 18 and processes the data according to the driving torque demand Tr calculated by the VCU 12;

[0082] The VCU 12 realizes the switching of the redundant safe steering mode, the auxiliary drive mode and the energy recovery mode by controlling the connection or disconnection of the first electromagnetic clutch 5 and the second electromagnetic clutch 7 according to whether the steer-by-wire motor 18 is faulty and the driving torque demand Tr.

[0083] (II) The control method of the integrated system of the vehicle redundant steer-by-wire and auxiliary drive includes the redundant safe steering mode. The redundant safe steering mode includes the following steps:

[0084] If the VCU 12 judges that the steer-by-wire motor 18 is faulty, the redundant safe steering mode is executed; the VCU 12 controls the first electromagnetic clutch 5 to be connected, the second electromagnetic clutch 7 to be disconnected, and the auxiliary motor 6 to execute the electric drive mode to provide the steering assist.

[0085] Specifically, when the VCU 12 detects that the steer-by-wire motor 18 is faulty, the system automatically enters the redundant safe steering mode, and the working process of the system in the redundant safe steering mode is as follows:

[0086] (1) The VCU 12 detects the fault of the steer-by-wire: The VCU 12 monitors the working state of the steer-by-wire motor 18 in real time. Once the motor is found to be abnormal or invalid, the VCU 12 immediately starts the redundant safe steering mode.

[0087] (2) The electromagnetic clutch switching: The VCU 12 controls the first electromagnetic clutch 5 to be connected, so as to couple the auxiliary motor 6 with the second steering reducer 24. At the same time, the second electromagnetic clutch 7 is disconnected, so as to ensure that the auxiliary motor 6 is only used for steering and does not participate in driving.

[0088] (3) The auxiliary motor 6 provides steering assist: in the redundant safety steering mode, the auxiliary motor 6 transmits the steering torque through the second steering reducer 24 and the second rack and pinion mechanism 23, replacing the failed steer-by-wire motor 18, ensuring that the vehicle can still steer normally in an emergency.

[0089] (4) Steering torque transmission: the steering torque generated by the auxiliary motor 6 is transmitted to the steering tie rod 4 through the second rack and pinion mechanism 23, and then to the wheels 1 through the trapezoidal arm 3 and the steering knuckle 25, realizing the rotation of the wheels 1.

[0090] (Three) The control method of the vehicle redundant steer-by-wire and auxiliary drive integrated system of the application includes an auxiliary drive mode. When the steer-by-wire motor 18 is working normally without failure, the system determines whether to enter the auxiliary drive mode and energy recovery mode. When the steer-by-wire motor 18 is working normally without failure and the vehicle driving torque demand is greater than or equal to 0, it is determined that the vehicle is in the auxiliary drive mode.

[0091] The auxiliary drive mode includes the following steps:

[0092] If the VCU 12 determines that the steer-by-wire motor 18 has no failure, it initially determines the driving torque demand Tr. If Tr>0, the auxiliary drive mode is executed, and the driving torque demand Tr is determined again. If Tr≤Ta, the constant speed drive mode is executed. The VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be disconnected, the auxiliary motor 6 to stop working, and the driving motor 11 to provide driving torque alone. If Tr>Ta, the acceleration drive mode is executed. The VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be connected, and the auxiliary motor 6 to execute the auxiliary drive mode. The driving motor 11 and the auxiliary motor 6 cooperatively provide driving torque.

[0093] Specifically, in the auxiliary drive mode, the main task of the auxiliary motor 6 in this mode is to provide additional driving torque cooperatively with the driving motor 11, especially when the vehicle needs high torque or acceleration. The detailed working process of the auxiliary drive mode is as follows:

[0094] (1) The VCU 12 initially determines the driving torque demand: the VCU 12 detects that the steer-by-wire motor 18 has no failure, and then initially determines the driving torque demand Tr. If Tr>0, the auxiliary drive mode is executed.

[0095] (2) The VCU 12 determines the driving torque demand again: the VCU 12 determines whether the auxiliary motor 6 needs to participate in driving according to the driving torque demand Tr of the vehicle and the maximum output torque Ta of the driving motor 11.

[0096] (3) Constant speed drive mode:

[0097] When Tr ≤ Ta, the driving motor 11 can independently meet the driving force demand of the vehicle, the system enters the uniform speed driving mode, the first electromagnetic clutch 5 and the second electromagnetic clutch 7 are disconnected, the auxiliary motor 6 does not work, the driving motor 11 provides the driving torque through the main transmission shaft 16 and the differential 22 alone, and the vehicle is driven forward.

[0098] (4) Acceleration driving mode:

[0099] When Tr > Ta, the driving motor 11 cannot independently provide sufficient driving force, the system enters the acceleration driving mode, the VCU 12 controls the second electromagnetic clutch 7 to be connected, the auxiliary motor 6 is coupled with the planetary gear mechanism 8, the torque is adjusted through the planetary gear mechanism 8, the auxiliary motor 6 and the driving motor 11 jointly provide the driving torque, so as to meet the high-torque demand working condition such as vehicle starting or sudden acceleration.

[0100] (5) Driving torque transmission: in the acceleration driving mode, the auxiliary motor 6 and the driving motor 11 work cooperatively, the driving force is transmitted to the differential 22 through the main transmission shaft 16, the differential 22 reasonably distributes the driving force to the half shaft 20, and finally the wheel hub 2 drives the wheel 1 to rotate.

[0101] (4) The control method of the integrated system of the vehicle redundancy steer-by-wire and auxiliary driving described in the application comprises an energy recovery mode. When the steer-by-wire motor 18 is normally working without failure, the system determines the auxiliary driving mode and the energy recovery mode. When the steer-by-wire motor 18 is failure-free and the vehicle driving torque demand is less than or equal to 0, it is determined that the vehicle is in the energy recovery mode.

[0102] The energy recovery mode comprises the following steps:

[0103] If Tr ≤ 0, the energy recovery mode is executed; if the energy recovery mode is executed, the VCU 12 controls the first electromagnetic clutch 5 to be disconnected, the second electromagnetic clutch 7 to be connected, the VCU 12 controls the auxiliary motor 6 to be reversed to provide a reverse torque to realize power generation, and the VCU 12 controls the driving motor 11 to stop working.

[0104] Specifically, in the energy recovery mode, the auxiliary motor 6 recovers energy when the vehicle is sliding or braking, and converts kinetic energy into electrical energy stored in the power supply 10. The working process of the energy recovery mode is as follows:

[0105] When the vehicle is in a sliding state (i.e., the driver releases the accelerator pedal, but does not step on the brake pedal), the driving torque demand Tr ≤ 0, and the system automatically enters the sliding energy recovery mode.

[0106] (1) VCU12 judges the driving torque demand: VCU12 monitors the driving torque demand of the vehicle in real time, and determines that the vehicle is in the coasting state when Tr≤ 0 and no brake signal is detected.

[0107] (2) Electromagnetic clutch control:

[0108] VCU12 controls the first electromagnetic clutch 5 to be disconnected, ensuring that the auxiliary motor 6 is separated from the steering system and does not affect steering operation. At the same time, the second electromagnetic clutch 7 is connected, ensuring that the auxiliary motor 6 is coupled with the planetary gear mechanism 8, and the driving motor 11 stops working to avoid driving torque output.

[0109] (3) Auxiliary motor 6 reverse power generation: During coasting, the auxiliary motor 6 operates in reverse through the planetary gear mechanism 8, generating power using the inertia of the vehicle. The kinetic energy of the wheels is transmitted to the auxiliary motor 6 through the transmission system, and the auxiliary motor 6 converts the kinetic energy into electrical energy.

[0110] (4) Electrical energy storage: The generated electrical energy is converted into direct current by the inverter 9 and stored in the vehicle's power supply 10 system for future use.

[0111] (5) System recovery: After the coasting ends, if the vehicle needs to be driven again (for example, the driver steps on the accelerator pedal), the system automatically exits the coasting energy recovery mode, the auxiliary motor 6 stops generating power, and the driving motor 11 resumes normal operation mode.

[0112] When the vehicle is in the braking state (i.e., the driver steps on the brake pedal), the system enters the braking energy recovery mode.

[0113] (1) VCU12 judges the braking state: VCU12 determines that the vehicle is in the braking state when it detects that the driving torque demand Tr≤ 0 and there is a brake signal. The system automatically switches to the braking energy recovery mode.

[0114] (2) Electromagnetic clutch control:

[0115] VCU12 controls the first electromagnetic clutch 5 to be disconnected, ensuring that the auxiliary motor 6 is separated from the steering system, and the second electromagnetic clutch 7 remains connected, ensuring that the auxiliary motor 6 is coupled with the planetary gear mechanism 8. The driving motor 11 stops working in this state.

[0116] (3) Auxiliary motor 6 reverse power generation: During braking, the deceleration of the vehicle causes the kinetic energy of the wheels to be transmitted to the auxiliary motor 6 through the transmission system. The auxiliary motor 6 operates in reverse under the control of VCU12 to generate power and convert the kinetic energy into electrical energy.

[0117] (4) Electric energy storage: the electric energy generated by the auxiliary motor 6 is converted into direct current by the inverter 9 and stored in the power supply 10 system. This process effectively recovers the braking energy and reduces the mechanical energy loss of the brake system.

[0118] (5) After braking: when the vehicle stops braking or needs to accelerate again, the VCU 12 control system exits the braking energy recovery mode, the auxiliary motor 6 stops generating electricity, and the drive motor 11 resumes the normal driving mode.

[0119] The application integrates the steer-by-wire and drive-by-wire systems, and uses the coupling mode switching of the auxiliary motor and the electromagnetic clutch to solve the safety problem of the traditional steer-by-wire system when the steer-by-wire motor fails, and can realize safer and more efficient vehicle steering and driving, while improving the energy utilization efficiency of the vehicle under different working conditions.

[0120] It should be understood that although the present specification is described in terms of various embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

[0121] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the application, and are not intended to limit the protection scope of the application, and any equivalent embodiments or changes made without departing from the spirit of the application should be included in the protection scope of the application.

Claims

1. An integrated system of vehicle redundant steer-by-wire and auxiliary drive, characterized by, The steering mechanism, the driving mechanism, the steer-by-wire motor (18), the auxiliary motor (6), the first electromagnetic clutch (5), the second electromagnetic clutch (7), the energy storage mechanism, the VCU (12), the detection mechanism (13) and the steering shaft (14) are included. The steer-by-wire motor (18) is connected with the first steering reducer (19) and the steering mechanism, and is used to rotate the wheel (1). The driving mechanism includes the driving motor (11), the main transmission shaft (16) and the half shaft (20), the driving motor (11) is connected with the input end of the main transmission shaft (16), the output end of the main transmission shaft (16) is connected with the half shaft (20), and the two ends of the half shaft (20) are respectively connected with the hubs (2) of the wheels (1) on the two sides. The auxiliary motor (6) is connected with the second steering reducer (24) and the steering mechanism, the first electromagnetic clutch (5) is installed between the auxiliary motor (6) and the second steering reducer (24), the first electromagnetic clutch (5) is used to control the coupling of the auxiliary motor (6) and the steering mechanism, the auxiliary motor (6) is connected with the main transmission shaft (16) through the planetary gear mechanism (8), the second electromagnetic clutch (7) is installed between the auxiliary motor (6) and the planetary gear mechanism (8), and the second electromagnetic clutch (7) is used to control the coupling of the auxiliary motor (6) and the driving motor (11). The energy storage mechanism is connected with the auxiliary motor (6) and the driving motor (11) respectively. The detection mechanism (13) is connected with the output end of the steering shaft (14), is used to collect the rotation angle signal and the torque signal, and transmits the rotation angle signal and the torque signal to the VCU (12), and the input end of the steering shaft (14) is connected with the steering wheel (15). The VCU (12) is connected with the steer-by-wire motor (18), the auxiliary motor (6), the driving motor (11), the first electromagnetic clutch (5), the second electromagnetic clutch (7) and the detection mechanism (13) respectively, the VCU (12) monitors the running state of the steer-by-wire motor (18) and the driving torque demand Tr in real time, controls the connection or disconnection of the first electromagnetic clutch (5) and the second electromagnetic clutch (7), and realizes the switching of the working mode. The working mode includes the redundant safe steering mode, the auxiliary driving mode and the energy recovery mode. The VCU (12) monitors the driving torque demand Tr and the self-checking data of the steer-by-wire motor (18) in real time, processes the data, and judges whether the steer-by-wire motor (18) fails. If the steer-by-wire motor (18) fails, the redundant safe steering mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be connected, the second electromagnetic clutch (7) to be disconnected, and the auxiliary motor (6) to execute the electric mode to provide the steering assist; If the steer-by-wire motor (18) does not fail, the driving torque demand Tr is determined preliminarily, if Tr>0, the auxiliary driving mode is executed, and if Tr≤0, the energy recovery mode is executed. If the auxiliary drive mode is executed, the driving torque demand Tr is determined again, if Tr≤Ta, the uniform speed drive mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected, the second electromagnetic clutch (7) to be disconnected, the VCU (12) controls the auxiliary motor (6) to stop working, the driving motor (11) provides the driving torque alone; if Tr>Ta, the acceleration drive mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected, the second electromagnetic clutch (7) to be connected, the auxiliary motor (6) executes the auxiliary drive mode, the driving motor (11) and the auxiliary motor (6) cooperatively provide the driving torque; If the energy recovery mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected, the second electromagnetic clutch (7) to be connected, the VCU (12) controls the auxiliary motor (6) to be reversed, to provide a reverse torque, to realize power generation; the VCU (12) controls the driving motor (11) to stop working.

2. The integrated system of redundant steer-by-wire and auxiliary drive for a vehicle of claim 1, wherein, The driving mechanism further comprises a main reducer (17) and a differential (22); The output end of the main transmission shaft (16) is connected with the input end of the differential (22), for transmitting the driving torque, and the output end of the differential (22) is connected with the half shaft (20); The main reducer (17) is connected with the main transmission shaft (16).

3. The integrated system of redundant steer-by-wire and auxiliary drive for a vehicle of claim 1, wherein, The steering mechanism comprises a trapezoidal arm (3), a steering tie rod (4), a first rack and pinion mechanism (21) and a second rack and pinion mechanism (23); The two ends of the steering tie rod (4) are respectively connected with the trapezoidal arms (3), and the trapezoidal arms (3) are respectively connected with the half shafts (20) through steering knuckles (25); The steer-by-wire motor (18) is connected with the input end of the first steering reducer (19) and the first rack and pinion mechanism (21), the output end of the first rack and pinion mechanism (21) is connected with the steering tie rod (4), the torque of the steer-by-wire motor (18) is transmitted to the steering tie rod (4), for rotating the wheels (1); The auxiliary motor (6) is connected with the input end of the second steering reducer (24) and the second rack and pinion mechanism (23), the output end of the second rack and pinion mechanism (23) is connected with the steering tie rod (4), the torque of the auxiliary motor (6) is transmitted to the steering tie rod (4), for rotating the wheels (1).

4. The integrated system of redundant steer-by-wire and auxiliary drive for a vehicle of claim 1, wherein, The sun gear of the planetary gear mechanism (8) is connected with the auxiliary motor (6), and the planetary carrier is fixed, the outer gear ring of the planetary gear mechanism (8) is connected with the main transmission shaft (16) through gear meshing.

5. The integrated system of redundant steer-by-wire and auxiliary drive for a vehicle of claim 1, wherein, The energy storage mechanism comprises an inverter (9) and a power supply (10); the inverter (9) is arranged between the auxiliary motor (6) and the power supply (10), the inverter (9) is used for converting the alternating current generated during energy recovery into direct current and storing it in the power supply (10), the inverter (9) is also connected with the driving motor (11), for converting the direct current of the power supply (10) into alternating current and supplying it to the driving motor (11) when needed.

6. A control method of the integrated system of the vehicle redundant steer-by-wire and auxiliary drive according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: The VCU (12) monitors the running state of the steer-by-wire motor (18) and the driving torque demand Tr in real time; The VCU (12) switches the redundant safe steering mode, the auxiliary driving mode and the energy recovery mode by controlling the connection or disconnection of the first electromagnetic clutch (5) and the second electromagnetic clutch (7) according to whether the steer-by-wire motor (18) fails and the driving torque demand Tr.

7. The control method of the integrated system of vehicle redundant steer-by-wire and auxiliary drive according to claim 6, characterized in that, The redundant safe steering mode includes the following steps: If the VCU (12) determines that the steer-by-wire motor (18) fails, the redundant safe steering mode is executed; the VCU (12) controls the first electromagnetic clutch (5) to be connected and the second electromagnetic clutch (7) to be disconnected, and the auxiliary motor (6) executes the electric mode to provide steering assistance.

8. The control method of the integrated system of vehicle redundant steer-by-wire and auxiliary drive according to claim 7, characterized in that, The auxiliary driving mode includes the following steps: If the VCU (12) determines that the steer-by-wire motor (18) does not fail, the driving torque demand Tr is initially determined, if Tr>0, the auxiliary driving mode is executed, and the driving torque demand Tr is determined again, if Tr≤Ta, the constant speed driving mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected and the second electromagnetic clutch (7) to be disconnected, the VCU (12) controls the auxiliary motor (6) to stop working, and the driving motor (11) provides driving torque alone; if Tr>Ta, the acceleration driving mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected and the second electromagnetic clutch (7) to be connected, the auxiliary motor (6) executes the auxiliary driving mode, and the driving motor (11) and the auxiliary motor (6) cooperatively provide driving torque.

9. The control method of the integrated system of vehicle redundant steer-by-wire and auxiliary drive according to claim 8, characterized in that, The energy recovery mode includes the following steps: If Tr≤0, the energy recovery mode is executed; if the energy recovery mode is executed, the VCU (12) controls the first electromagnetic clutch (5) to be disconnected and the second electromagnetic clutch (7) to be connected, the VCU (12) controls the auxiliary motor (6) to be reversed to provide a reverse torque to realize power generation, and the VCU (12) controls the driving motor (11) to stop working.

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