CN117885805A

CN117885805A - Redundant electric power steering control system and control method for automatic driving vehicle

Info

Publication number: CN117885805A
Application number: CN202410302282.4A
Authority: CN
Inventors: 侯诗扬; 高峰; 吴立阳
Original assignee: Qingche Zhixing Suzhou Electronic Technology Co ltd
Current assignee: Qingche Zhixing Suzhou Electronic Technology Co ltd
Priority date: 2024-03-18
Filing date: 2024-03-18
Publication date: 2024-04-16
Anticipated expiration: 2044-03-18

Abstract

The invention discloses a redundant electric power steering control system and a control method of an automatic driving vehicle, wherein the system comprises a first control subsystem, a second control subsystem and a steering motor, and the output ends of the first control subsystem and the second control subsystem are respectively and electrically connected with the steering motor; the first control subsystem and the second control subsystem are configured with fault zone bits and different role zone bits so that one is a master system and the other is a slave system, and the fault zone bits of the first control subsystem and the second control subsystem are determined according to the running conditions of the first control subsystem and the second control subsystem; and determining a first steering torque instruction output by the main system to the steering motor and a second steering torque instruction output by the main system to the steering motor according to the target steering torque of the vehicle, and the role zone bit and the fault zone bit of the first control subsystem and the second control subsystem. The invention can reduce the overall failure rate of the electric power steering control system and improve the safety of the electric power steering control system.

Description

Redundant electric power steering control system and control method for automatic driving vehicle

Technical Field

The invention relates to the technical field of steering control of automobiles, in particular to a redundant electric power steering control system and a control method of an automatic driving vehicle.

Background

The intelligent and networking of automobiles is deeply developed, high-level assisted driving automobiles gradually start mass production application, automatic driving automobiles and intelligent networking automobiles start open road scene tests in a certain scale, mass production landing is expected, and more intelligent and safer automobiles are future development trends. The steering system is a key actuating mechanism for controlling and realizing the transverse movement of the vehicle, and compared with a traditional automobile, the automatic driving automobile has higher safety requirement on the steering system. Specifically, the core electric control system of the steering system is required to have a redundant backup design, so that the steering system still has the steering moment output capability when single-point faults occur, and the vehicle is in a controlled state before the driver takes over, so that the problems of steering incapability, unexpected steering and the like caused by immediately turning off the power-assisted output are avoided.

The electronic control unit (Electric Control Unit, ECU) of the traditional electric power steering (Electric Power Steering, EPS) only has a set of electric control system taking the micro control unit (Microcontroller Unit, MCU) as a core, redundancy-free backup is achieved, the fault processing mode after single-point fault is power-off, the power-assisted steering enters a fail-safe (fail-safe) safety mode, and the steering of the vehicle cannot be controlled through the electric control system, so that the traditional EPS system cannot meet the safety requirement of an automatic driving automobile. At present, a redundant EPS with a double-ECU system becomes a necessary configuration for automatic driving and high-level auxiliary driving of an automobile, and the redundant EPS electric control system is provided with two independent ECU subsystems and mutually independent signal inputs, when one of the two electronic subsystems has single-point faults, the ECU can judge the severity of the faults, if necessary, the fault subsystem is closed, and the normal subsystem provides moment output, so that the steering movement of the automobile between the occurrence of faults and the intervention of a driver is still controlled, namely 'failure-operation'.

Currently, there are few inventive approaches to focus redundant EPS control systems and methods, the disclosure focusing on controller circuit arrangements (as disclosed in the patent document with publication No. CN 214420543U), PCBA structures (as disclosed in the patent document with publication No. CN 219227946U), booster control devices (as disclosed in the patent document with publication No. CN 216185445U), control systems (as disclosed in the patent document with publication No. CN 215851452U), and steering systems (as disclosed in the patent document with publication No. CN 210912592U), with little disclosure of how to implement fail-operable control methods based on dual system redundancy. The Chinese patent with publication number CN114644036A proposes a control method of a highly redundant electric power steering system, 9 failure modes of a dual system, such as torque angle, steering motor rotation angle, MCU, CAN, communication and the like are designed, the power-assisted output ratio of two subsystems is determined according to specific parts which fail in each failure mode, the control strategy is simpler, the highest power-assisted output ratio in a failure state is 50%, and half power-assisted output capacity of the original system is reserved. The control method of the redundant electric power steering system has low utilization degree of the steering motor and limits the whole torque output capacity of the redundant EPS, so that the control capacity of the vehicle after the fault is insufficient.

The above disclosure of background art is only for aiding in understanding the inventive concept and technical solution of the present application, and it does not necessarily belong to the prior art of the present patent application, nor does it necessarily give technical teaching; the above background should not be used to assess the novelty and creativity of the present application in the event that no clear evidence indicates that such is already disclosed prior to the filing date of the present patent application.

Disclosure of Invention

The invention aims to provide a redundant electric power steering control system and a control method of an automatic driving vehicle, which can reduce the overall failure rate of the electric power steering control system and improve the safety of the electric power steering control system.

In order to achieve the above purpose, the invention adopts the following technical scheme:

A redundant electric power steering control system for an autonomous vehicle, comprising: the system comprises a first control subsystem, a second control subsystem and a steering motor, wherein the output ends of the first control subsystem and the second control subsystem are respectively and electrically connected with the steering motor;

The first control subsystem and the second control subsystem are configured with different role flags so that one is a master system and the other is a slave system, and the role flags comprise the master system and the slave system;

The first control subsystem and the second control subsystem are further configured with fault zone bits, the fault zone bits comprise no fault, slight fault, serious fault and ultimate fault, the fault zone bits of the first control subsystem are determined according to the running condition of the first control subsystem, and the fault zone bits of the second control subsystem are determined according to the running condition of the second control subsystem;

Determining a first steering torque instruction output by the main system to the steering motor and a second steering torque instruction output by the auxiliary system to the steering motor according to a target steering torque during running of the vehicle, and the role zone bit and the fault zone bit of the first control subsystem and the second control subsystem, wherein the first steering torque instruction corresponds to the output first steering torque of the steering motor, the second steering torque instruction corresponds to the output second steering torque of the steering motor, and the steering torque actually output by the steering motor is the sum of the first steering torque and the second steering torque.

Further, any one or a combination of the foregoing technical solutions, the role flags of the first control subsystem and the second control subsystem are configured by:

Presetting role zone bits of the first control subsystem and the second control subsystem so that one of the role zone bits is preset as a master system and the other role zone bit is preset as a slave system;

If the current fault zone bit of the master system is not higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem and the second control subsystem are unchanged;

If the current fault zone bit of the master system is higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem and the second control subsystem are exchanged;

the order of the fault zone bit from low to high is no fault, slight fault, serious fault and ultimate fault.

Further, the master system has a preset first allocation coefficient f _TrqFac and the slave system has a preset second allocation coefficient 1-f _TrqFac;

If the fault flag bits of the master system and the slave system have no faults, the first steering torque T ₁ is T _DMD×f_TrqFac, and the second steering torque T ₂ is T _DMD×(1-f_TrqFac), where T _DMD is the target steering torque.

If the failure zone bit of the master system is failure-free, the failure zone bits of the slave system are all light failures, the first steering torque T ₁ is T _DMD×f_TrqFac×f_sp, the second steering torque T ₂ is T _DMD×(1-f_TrqFac)_×f_sp, wherein T _DMD is a target steering torque, f _sp is a power-down protection coefficient, and f _sp is less than 1.

If the failure zone bit of the master system is failure-free, the failure zone bits of the slave system are all light failures, the first steering torque T ₁ is T _DMD×f_TrqFac, the second steering torque T ₂ is T _DMD×(1-f_TrqFac)_×f_sp, wherein T _DMD is a target steering torque, f _sp is a power-down protection coefficient, and f _sp is less than 1.

Further, in any one or a combination of the foregoing aspects, the power-reducing protection coefficient f _sp is not less than 0.6 and not more than 1; or alternatively

The power-down protection coefficient f _sp is 0.8 or 0.9.

If the failure flag bit of the master system is no failure and the failure flag bits of the slave systems are all serious failures, the second steering torque T ₂ is 0, and the first steering torque T ₁ satisfies the following formula:

Wherein T _DMD is the target steering torque, and T _MotCap is the maximum steering torque of the steering motor.

Further, any one or a combination of the foregoing, the first distribution coefficient f _TrqFac is 0.5 to 0.65; or alternatively

The first partition coefficient f _TrqFac is 0.5 or 0.6.

Further, in any one or a combination of the foregoing technical solutions, if the failure flag bit of the master system is a light failure and the failure flag bits of the slave systems are all light failures, the first steering torque T ₁ and the second steering torque T ₂ are both 0; and/or the number of the groups of groups,

If the fault zone bit of the master system is a slight fault and the fault zone bit of the slave system is a serious fault, the first steering torque T ₁ and the second steering torque T ₂ are both 0; and/or the number of the groups of groups,

If the fault zone bits of the master system and the slave system are all serious faults, the first steering moment T ₁ and the second steering moment T ₂ are both 0; and/or the number of the groups of groups,

If one of the fault flag bits in the master system and the slave system is an ultimate fault, the first steering torque T ₁ and the second steering torque T ₂ are both 0.

Further, in combination with any one or more of the foregoing aspects, a power-assisted control model and an angle control model are disposed in the first control subsystem and the second control subsystem, the power-assisted control model is configured to determine a power-assisted initial torque command according to a steering wheel angle, a hand torque and a vehicle speed in a manual driving mode to send the power-assisted initial torque command to the steering motor, and the angle control model is configured to determine a steering initial torque command according to the steering wheel angle and the vehicle speed in an automatic driving mode to send the power-assisted initial torque command to the steering motor.

Further, the system further comprises a vehicle-mounted power supply, a whole vehicle CAN network and a steering wheel torque angle sensor;

the first control subsystem is electrically connected with a vehicle-mounted power supply, a whole vehicle CAN network and a steering wheel torque angle sensor respectively, and the steering wheel torque angle sensor is configured to collect steering wheel torque signals and angle signals and transmit the steering wheel torque signals and angle signals to the first control subsystem;

the second control subsystem is electrically connected with the vehicle-mounted power supply, the whole vehicle CAN network and the steering wheel torque angle sensor respectively, and the steering wheel torque angle sensor is configured to collect steering wheel torque signals and angle signals and transmit the steering wheel torque signals and angle signals to the second control subsystem;

the first control subsystem and the second control subsystem determine a target steering torque of the vehicle based on the steering wheel torque signal and the angle signal.

Further, in combination with any one or more of the preceding claims, the first control subsystem includes a first central control unit, a first pre-drive unit, a first three-phase drive axle unit, a first current sampling unit, a first power management unit, a first drive axle temperature sensor, a first ambient temperature sensor, a first correlation breaking unit, a first CAN communication unit, and a first motor position sensor, wherein the first current sampling unit is configured to collect a current signal of the steering motor, the first drive axle temperature sensor is configured to monitor a temperature of the first three-phase drive axle unit, and the first ambient temperature sensor is configured to monitor an ambient temperature;

the input end of the first central control unit is electrically connected with the signal feedback end of the first pre-driving unit, the output end of the first power management unit, the output ends of the first drive axle temperature sensor and the steering wheel torque angle sensor, the output end of the first ambient temperature sensor and the bus port of the first CAN communication unit respectively, and the output ends of the first central control unit and the first power management unit are electrically connected with the steering motor;

the input end of the first pre-driving unit is electrically connected with the output ends of the first central control unit and the first current sampling unit and the signal feedback end of the first three-phase driving bridge unit, the output end of the first pre-driving unit is electrically connected with the input end of the first central control unit and the driving input end of the first three-phase driving bridge unit, and the first pre-driving unit is configured to drive the first three-phase driving bridge unit to control the working state of the steering motor;

The input end of the first three-phase drive axle unit is also electrically connected with the output feedback port of the first correlation breaking unit and the output end of the first current sampling unit, and the output end of the first three-phase drive axle unit is electrically connected with the input control port of the first correlation breaking unit and the input end of the first current sampling unit and is configured to control the working state of the steering motor;

the input end of the first power management unit is electrically connected with the output end of the first central control unit and the vehicle-mounted power supply;

The output end of the first correlation breaking unit is electrically connected with the input end of the steering motor and is configured to switch and control the connection between the first three-phase drive axle unit and the steering motor;

the first central control unit is in communication connection with the whole vehicle CAN network through the first CAN communication unit;

the first motor position sensor is configured to monitor a position of a rotor of the steer motor and transmit position information of the rotor of the steer motor to the first central control unit.

Further, in combination with any one or more of the preceding claims, the second control subsystem includes a second central control unit, a second pre-drive unit, a second three-phase drive axle unit, a second current sampling unit, a second power management unit, a second drive axle temperature sensor, a second ambient temperature sensor, a second phase shutdown unit, a second CAN communication unit, and a second motor position sensor, wherein the second current sampling unit is configured to collect a current signal of the steering motor, the second drive axle temperature sensor is configured to monitor a temperature of the second three-phase drive axle unit, and the second ambient temperature sensor is configured to monitor an ambient temperature;

The input end of the second central control unit is electrically connected with the signal feedback end of the second pre-driving unit, the output end of the second power management unit, the output ends of the second drive axle temperature sensor and the steering wheel torque angle sensor, the output end of the second environment temperature sensor and the bus port of the second CAN communication unit respectively, and the output ends of the second central control unit and the second power management unit are electrically connected with the steering motor;

the input end of the second pre-driving unit is electrically connected with the output ends of the second central control unit and the second current sampling unit and the signal feedback end of the second three-phase driving bridge unit, the output end of the second pre-driving unit is electrically connected with the input end of the second central control unit and the driving input end of the second three-phase driving bridge unit, and the second pre-driving unit is configured to drive the second three-phase driving bridge unit to control the working state of the steering motor;

The input end of the second three-phase drive axle unit is also electrically connected with the output feedback port of the second phase turn-off unit and the output end of the second current sampling unit, and the output end of the second three-phase drive axle unit is electrically connected with the input control port of the second phase turn-off unit and the input end of the second current sampling unit and is configured to control the working state of the steering motor;

the input end of the second power management unit is electrically connected with the output end of the second central control unit and the vehicle-mounted power supply;

The output end of the second phase turn-off unit is electrically connected with the input end of the steering motor and is configured to switch control on and off the connection between the second three-phase drive axle unit and the steering motor;

the second central control unit is in communication connection with the whole vehicle CAN network through the second CAN communication unit;

the second motor position sensor is configured to monitor a position of a rotor of the steer motor and transmit position information of the rotor of the steer motor to the second central control unit.

Further, in combination with any one or more of the foregoing aspects, the slight fault is a single point failure fault of a peripheral signal of a redundant electric power steering control system of the autonomous vehicle;

the serious fault is an internal fault of a central control unit of the first control subsystem or the second control subsystem;

the ultimate fault is a fault that causes the central control unit of the first control subsystem and/or the second control subsystem to fail in function due to the fact that the central control unit does not have normal control.

Further, the slight fault is one of a single-path signal fault, a single-path CAN signal fault, a single-path MPS signal fault, a single-path power supply fault and a single-path current sampling fault of the steering wheel torque angle sensor;

the serious fault is one of a single-path component fault, a single-phase motor three-phase fault, a single-path moment control or angle control fault and an inter-board communication fault of a central control unit of the first control subsystem or the second control subsystem;

The final fault is one or more of a peripheral signal double-point or multi-point failure of the redundant electric power steering control system of the autonomous vehicle, a double-point or multi-point failure inside a central control unit of the first control subsystem and/or the second control subsystem, and a double three-phase fault of the motor.

According to another aspect of the present invention, there is provided a redundant electric power steering control method of an autonomous vehicle, the redundant electric power steering control system of the autonomous vehicle being used to control a motor of the vehicle to control steering of the vehicle, the method comprising:

The role zone bits of the first control subsystem and the second control subsystem are preconfigured, so that one is a master system and the other is a slave system;

Determining fault zone bits of the first control subsystem and the second control subsystem at present;

Determining the role zone bit in the first control subsystem and the second control subsystem at present according to the role zone bit preset by the first control subsystem and the second control subsystem and the fault zone bit thereof;

and distributing steering torque command values of the first control subsystem and the second control subsystem according to target steering torque during running of the vehicle and role zone bits and fault zone bits of the first control subsystem and the second control subsystem, wherein the steering torque command values comprise a first steering torque command which is output by the main system to the steering motor and a second steering torque command which is output by the auxiliary system to the steering motor, the first steering torque command corresponds to the output first steering torque of the steering motor, and the second steering torque command corresponds to the output second steering torque of the steering motor.

Further, any one or a combination of the foregoing solutions, before determining the role flags of the first control subsystem and the second control subsystem, further includes:

A first power-assisted control model and a first angle control model are preset in the first control subsystem, a second power-assisted control model and a second angle control model are preset in the second control subsystem, the first power-assisted control model and the second power-assisted control model are configured to determine a power-assisted initial moment instruction and send the power-assisted initial moment instruction to the steering motor in a manual driving mode, and the first angle control model and the second angle control model are configured to determine a steering initial moment instruction and send the steering initial moment instruction to the steering motor in an automatic driving mode;

The first control subsystem and the second control subsystem respectively receive a starting signal, a steering wheel torque signal and an angle signal acquired by a steering wheel torque angle sensor, and a vehicle speed signal and a driving mode signal;

if the driving mode signal is a manual driving mode, the first control subsystem determines a first auxiliary initial moment instruction through the first auxiliary control model according to the steering wheel angle, the hand moment and the vehicle speed and sends the first auxiliary initial moment instruction to the steering motor, and the second control subsystem determines a second auxiliary initial moment instruction through the second auxiliary control model according to the steering wheel angle, the hand moment and the vehicle speed and sends the second auxiliary initial moment instruction to the steering motor;

if the driving mode signal is an automatic driving mode, the first control subsystem determines a first steering initial moment instruction according to the steering wheel angle and the vehicle speed through the first angle control model and sends the first steering initial moment instruction to the steering motor, and the second control subsystem determines a second steering initial moment instruction according to the steering wheel angle and the vehicle speed through the second angle control model and sends the second steering initial moment instruction to the steering motor;

The first control subsystem and the second control subsystem are used for detecting the fault condition of the system and the fault condition of other components of the redundant electric power steering control system of the automatic driving vehicle, and determining the fault sign of the first control subsystem as the fault sign bit of the second control subsystem according to the detection result.

Further, in any one or a combination of the foregoing aspects, after allocating the steering torque command values of the first control subsystem and the second control subsystem, the method further includes:

The first control subsystem judges whether moment protection is carried out according to the temperature and the voltage of the first pre-driving unit in the first control subsystem, corrects the first steering initial moment instruction according to the judging result, judges whether moment protection is carried out according to the temperature and the voltage of the first pre-driving unit in the first control subsystem, and corrects the second steering initial moment instruction according to the judging result.

The technical scheme provided by the invention has the following beneficial effects:

a. According to the invention, different role zone bits and different levels of fault zone bits are configured for the first control subsystem and the second control subsystem of the redundant EPS control system, the steering torque distribution values of the two subsystems are determined according to the target steering torque of the vehicle and the role zone bits and the fault zone bits of the two subsystems, so that the control of the redundant EPS control system is more reasonable, the overall failure rate of the EPS control system can be reduced, the safety of the EPS control system can be improved, and the two subsystems or one subsystem can completely enter a failure mode under the unnecessary condition is avoided;

b. the invention increases the failure operability of the EPS control system under the single point failure, and the peripheral single point failure does not affect the steering function of the vehicle, thereby further reducing the overall failure rate of the EPS control system and improving the functional safety of the EPS control system;

c. Compared with the existing redundant EPS control system and control method, the invention can realize the power-assisted output capability of more than 50% under the condition of single-point failure, realize the full utilization of the output performance of the steering motor, and is beneficial to improving the steering control capability of the whole vehicle under failure, thereby improving the overall safety of the vehicle;

d. Aiming at no fault of the main system and slight fault of the auxiliary system, the invention provides the auxiliary system which only carries out power reduction and assistance treatment on the slight fault, maintains the original output capability of the main system, and can further reduce the integral failure rate of the redundant EPS control system and improve the functional safety of the redundant EPS control system.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.

FIG. 1 is a hardware architecture diagram of an electric power steering control system provided in an exemplary embodiment of the present invention;

FIG. 2 is a signal transmission schematic diagram of an electric power steering control system according to an exemplary embodiment of the present invention;

Fig. 3 is a flowchart of an electric power steering control method according to an exemplary embodiment of the present invention.

Wherein, the reference numerals include: the system comprises a first control subsystem, a first central control unit, a first pre-driving unit, a first three-phase driving axle unit, a first current sampling unit, a first power management unit, a first driving axle temperature sensor, a first environment temperature sensor, a first related breaking unit, a first Controller Area Network (CAN) communication unit, a first motor position sensor, a second control subsystem, a second central control unit, a first power management unit, a second central control unit, a second pre-driving unit, a third driving axle unit, a second three-phase driving axle unit, a second current sampling unit, a third current sampling unit, a fourth driving axle unit, a second power management unit, a third driving axle unit, a fourth driving axle unit, a fifth driving axle unit, a sixth driving axle unit, a fourth driving axle temperature sensor, a fifth driving axle temperature sensor, a fourth driving axle temperature sensor, a third environment temperature sensor, a fourth driving axle temperature sensor, a fourth related breaking unit, a fourth driving axle temperature sensor, a third and a fourth vehicle power source, a fifth vehicle CAN network, a fourth driving axle, a 6-steering wheel torque angle sensor and a 7-flexible circuit board.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or device.

In one embodiment of the present invention, there is provided a redundant electric power steering control system of an autonomous vehicle, referring to fig. 1, the redundant electric power steering control system including: the system comprises a first control subsystem 1, a second control subsystem 2 and a steering motor 3, wherein the output ends of the first control subsystem 1 and the second control subsystem 2 are respectively and electrically connected with the steering motor 3;

The first control subsystem 1 and the second control subsystem 2 are configured with different role flags so that one is a master system and the other is a slave system, and the role flags comprise the master system and the slave system;

The first control subsystem 1 and the second control subsystem 2 are further configured with fault zone bits, wherein the fault zone bits comprise no fault, slight fault, serious fault and ultimate fault, the fault zone bits of the first control subsystem 1 are determined according to the operation conditions of the fault zone bits, and the fault zone bits of the second control subsystem 2 are determined according to the operation conditions of the fault zone bits;

Determining a first steering torque command output by the main system to the steering motor 3 and a second steering torque command output by the auxiliary system to the steering motor 3 according to a target steering torque during running of the vehicle and the role zone bit and the fault zone bit of the first control subsystem 1 and the second control subsystem 2, wherein the first steering torque command corresponds to a first steering torque output by the steering motor 3, the second steering torque command corresponds to a second steering torque output by the steering motor 3, and the steering torque actually output by the steering motor 3 is the sum of the first steering torque and the second steering torque.

In one embodiment of the present invention, the hardware architecture of the redundant electric power steering control system is shown in fig. 1, and includes two sets of independently operating controller subsystems, namely, the first control subsystem 1 and the second control subsystem 2, which are respectively two parts of the ECU1 and the ECU2 enclosed by a dashed line frame in fig. 1, and are specifically embodied as two independent PCBA circuit boards, each having independent signal input and output interfaces, and the boards are electrically connected through a flexible circuit board 7, so as to be used for communication and transmission of inter-board signals, namely, the first control subsystem 1 and the second control subsystem 2. The system also comprises a vehicle-mounted power supply 4, a whole vehicle CAN network 5, a steering wheel torque angle sensor 6 and a motor rotation angle sensor (MPS). The steering wheel torque angle sensor 6 is configured to acquire a steering wheel torque signal and an angle signal and transmit them to the first control subsystem 1 and the second control subsystem 2. The motor rotation angle sensor (MPS) is configured to acquire an angle and a rotation speed signal of the steering motor 3 and transmit the signals to the first control subsystem 1 and the second control subsystem 2.

The first control subsystem 1 includes a first central control unit 11, a first pre-driving unit 12, a first three-phase driving axle unit 13, a first current sampling unit 14, a first power management unit 15, a first driving axle temperature sensor 16, a first ambient temperature sensor 17, a first correlation breaking unit 18, a first CAN communication unit 19 and a first motor position sensor 110.

The first central control unit 11 comprises a dual-core MCU chip and its peripheral circuits, and its input end is electrically connected with the signal feedback end of the first pre-driving unit 12, the output end of the first power management unit 15, the output ends of the first drive axle temperature sensor 16 and the steering wheel torque angle sensor 6, the output end of the first ambient temperature sensor 17 and the bus port of the first CAN communication unit 19, respectively; the output of which is electrically connected to the enabling input of the first power management unit 15, to the input of the first pre-drive unit 12 and to the input of the steering motor 3. The first central control unit 11 is configured to control the operation state of the entire ECU1, drive the operation of the steering motor 3, and communicate with an external bus.

The first pre-driving unit 12 includes a pre-driving chip and its peripheral circuit, the input end of the pre-driving chip is electrically connected to the output ends of the first central control unit 11 and the first current sampling unit 14, and the signal feedback end of the first three-phase driving bridge unit 13, the output end of the pre-driving unit is electrically connected to the input end of the first central control unit 11 and the driving input end of the first three-phase driving bridge unit 13, and the pre-driving unit is configured to drive the first three-phase driving bridge unit 13 to control the working state of the steering motor 3, so as to ensure the normal operation of the steering motor.

The first three-phase driving bridge unit 13 includes a motor driving circuit composed of six field effect transistors (mosfets), and an input end thereof is electrically connected to an output feedback port of the first correlation breaking unit 18 and an output end of the first current sampling unit 14, and an output end thereof is electrically connected to an input control port of the first correlation breaking unit 18 and an input end of the first current sampling unit 14, and is configured to control a working state of the steering motor 3, so as to ensure a normal operation of the steering motor.

The first current sampling unit 14 includes three resistors for phase current sampling, an input end of the three resistors is connected to an output end of the first three-phase drive bridge unit 13, an output end of the three resistors is connected to a current signal sampling port of the first pre-drive unit 12, and the three resistors are configured to collect three-phase current of the steering motor 3 in real time.

The first power management unit 15 includes a low dropout regulator (LDO) composed of a power chip and its peripheral circuits, an input terminal thereof is electrically connected to the output control terminal of the first central control unit 11 and the output terminal of the vehicle-mounted power supply 4, and an output terminal thereof is connected to the power input terminal of the first central control unit 11, and is configured to supply power to the ECU1 by using electrical components, so as to ensure the normal operation of the ECU 1.

The first drive axle temperature sensor 16 comprises a thermistor for measuring the temperature of the first three-phase drive axle unit 13, and its output port is connected to the AD sampling port of the first central control unit 11, and is configured to monitor the real-time temperature of the first three-phase drive axle unit 13.

The first ambient temperature sensor 17 comprises a thermistor for measuring ambient temperature, and an output port of the first ambient temperature sensor is connected with the AD sampling port of the first central control unit 11, and is used for monitoring the ambient temperature of the PCBA circuit board surface of the first central control unit 11 in real time and transmitting the ambient temperature to the first central control unit 11.

The first correlation breaking unit 18 comprises a phase cut-off protection circuit composed of three MOS transistors, and an output end thereof is electrically connected with an input end of the steering motor 3, and is configured to switch control on and off a connection between the first three-phase drive axle unit 13 and the steering motor 3.

The first CAN communication unit 19 includes a CAN transceiver chip and its peripheral circuits, and the first central control unit 11 is in communication connection with the whole vehicle CAN network 5 through the first CAN communication unit 19.

The first motor position sensor 110 includes a motor position sensor chip and its peripheral circuit, and its output port is connected to the SPI communication interface of the first central control unit 11, and is configured to monitor the rotor position of the steering motor, and feedback and output the monitored rotor position signal/information to the first central control unit 11.

The second control subsystem 2 includes a second central control unit 21, a second pre-driving unit 22, a second three-phase drive axle unit 23, a second current sampling unit 24, a second power management unit 25, a second drive axle temperature sensor 26, a second ambient temperature sensor 27, a second phase shutdown unit 28, a second CAN communication unit 29, and a second motor position sensor 210.

The input end of the second central control unit 21 is electrically connected to the signal feedback end of the second pre-driving unit 22, the output end of the second power management unit 25, the output ends of the second drive axle temperature sensor 26 and the steering wheel torque angle sensor 6, the output end of the second ambient temperature sensor 27 and the bus port of the second CAN communication unit 29, respectively, and the output ends thereof are electrically connected to the enabling input end of the second power management unit 25, the input end of the first pre-driving unit 12 and the input end of the steering motor 3. The second central control unit 21 is configured to control the operation state of the entire ECU2, drive the operation of the steering motor 3, and communicate with an external bus.

The input end of the second pre-driving unit 22 is electrically connected with the output ends of the second central control unit 21 and the second current sampling unit 24 and the signal feedback end of the second three-phase driving bridge unit 23, and the output end thereof is electrically connected with the input end of the second central control unit 21 and the driving input end of the second three-phase driving bridge unit 23, and is configured to drive the second three-phase driving bridge unit 23 to control the working state of the steering motor 3, so as to ensure the normal operation of the steering motor.

The second three-phase driving bridge unit 23 includes a motor driving circuit composed of six field effect transistors (mosfets), and an input end thereof is electrically connected to an output feedback port of the second phase shutdown unit 28 and an output end of the second current sampling unit 24, and an output end thereof is electrically connected to an input control port of the second phase shutdown unit 28 and an input end of the second current sampling unit 24, and is configured to control a working state of the steering motor 3, so as to ensure a normal operation of the steering motor.

The second current sampling unit 24 includes three resistors for phase current sampling, an input end of which is connected to an output end of the second three-phase drive bridge unit 23, and an output end of which is connected to a current signal sampling port of the second pre-drive unit 22, and is configured to collect three-phase current of the steering motor 3 in real time.

The second power management unit 25 includes a low dropout regulator (LDO) composed of a power chip and its peripheral circuits, an input terminal thereof is electrically connected to the output control terminal of the second central control unit 21 and the output terminal of the vehicle-mounted power supply 4, and an output terminal thereof is connected to the power input terminal of the second central control unit 21, and is configured to supply power to the electrical components of the ECU2, so as to ensure the normal operation of the ECU 2.

The second drive axle temperature sensor 26 comprises a thermistor for measuring the temperature of the second three-phase drive axle unit 23, and its output port is connected to the AD sampling port of the second central control unit 21, and is configured to monitor the real-time temperature of the second three-phase drive axle unit 23.

The second ambient temperature sensor 27 comprises a thermistor for measuring ambient temperature, and its output port is connected to the AD sampling port of the second central control unit 21, and is used for monitoring the ambient temperature of the PCBA circuit board surface of the second central control unit 21 in real time and transmitting the ambient temperature to the second central control unit 21.

The second phase turn-off unit 28 comprises a phase cut-off protection circuit composed of three MOS transistors, and an output end thereof is electrically connected with an input end of the steering motor 3, and is configured to switch control on and off connection between the second three-phase drive axle unit 23 and the steering motor 3.

The second CAN communication unit 29 includes a CAN transceiver chip and its peripheral circuits, and the second central control unit 21 is communicatively connected to the whole vehicle CAN network 5 through the second CAN communication unit 29.

The second motor position sensor 210 includes a motor position sensor chip and its peripheral circuit, and its output port is connected to the SPI communication interface of the second central control unit 21, and is configured to monitor the rotor position of the steering motor, and feedback and output the monitored rotor position signal to the second central control unit 21. The second motor position sensor 210 is configured to monitor the position of the rotor of the steer motor 3 and transmit position information of the rotor of the steer motor 3 to the second central control unit 21.

In this embodiment, the board-to-board communication between the first central control unit 11 and the second central control unit 21 is provided with three communication channels, namely a variable rate CAN communication protocol (CAN FD) channel, a Pulse Width Modulation (PWM) channel, and a high speed serial interface (HSCT) channel.

In this embodiment, the MCU chip sizes of the first central control unit 11 and the second central control unit 21 may be SAK-TC366DP-64F300S AA; the pre-driving chip model of the first pre-driving unit 12 and the second pre-driving unit 22 may be selected as TLE9183QK; the MOS transistor types of the first three-phase drive axle unit 13 and the second three-phase drive axle unit 23 may be IAUC120N04S6N006; the sampling resistor types of the first current sampling unit 14 and the second current sampling unit 24 can be selected as PSF4NTEBL F; the power chip types of the first power management unit 15 and the second power management unit 25 may be selected as TLF35585QUS01; the CAN transceiver model of the first CAN communication unit 19 and the second CAN communication unit 29 may be selected as TLE9255WLC; the model of the motor position sensor chip of the first motor position sensor 110 and the second motor position sensor 210 may be selected as TLE5014SP16D.

The steering wheel torque angle sensor 6 is configured to collect steering wheel torque signals and angle signals and transmit them to the first control subsystem 1 and the second control subsystem. Specifically, the output end of the steering wheel torque angle sensor 6 is electrically connected to the first central control unit 11 and the second central control unit 21, respectively. The first control subsystem 1 and the second control subsystem 2 determine a target steering torque of the vehicle from the steering wheel torque signal and the angle signal. And determining a first target steering torque distributed by the first control subsystem 1 and a second target steering torque distributed by the second control subsystem 1 according to the torque distribution proportion of the first control subsystem 1 and the second control subsystem 2, wherein the sum of the first target steering torque and the second target steering torque is the target steering torque.

The output end of the motor rotation angle sensor (MPS) is electrically connected to the first central control unit 11 and the second central control unit 21, respectively, and is configured to collect angle and rotation speed signals of the steering motor 3 and transmit the signals to the first central control unit 11 and the second central control unit 21.

In one embodiment of the invention, the steering motor 3 is a six-phase motor, the steering motor is a six-phase motor, and there are two independent three-phase windings, and the first control subsystem 1 and the second control subsystem 2 each control three phases thereof. The torque distribution ratio of the first control subsystem 1 and the second control subsystem 2 is 50%. I.e. the target steering torque allocated by the first control subsystem 1 and the second control subsystem 2 is half of the target steering torque of the vehicle.

The design scheme of the peripheral signals of the redundant electric power steering control system is shown in fig. 2, and the redundant EPS control system inputs two paths of CAN signals, two paths of power supply signals, two paths of starting signals (IG signals), four paths of steering wheel torque signals and two paths of steering wheel angle signals. The two CAN signals are respectively provided by two CAN wire harnesses, the two power supply signals are respectively provided by two power supply wires in parallel, and the four-way torque signal and the two-way angle signal of the steering wheel are provided by a steering wheel Torque Angle Sensor (TAS) with internal redundancy backup. The redundant EPS control system outputs PWM control signals to control the steering motor, namely the six-phase motor to output steering power-assisted torque.

Aiming at the redundant EPS control system with two control subsystems, the first control subsystem (A system shown in figure 2) inputs a first CAN signal, a first power supply signal, a first starting signal (IG signal), first and second steering wheel torque signals and a first angle signal, and outputs a PWM three-phase bridge control signal to control a first three-phase winding in a six-phase motor; the input signals of the second control subsystem (B system shown in fig. 2) comprise a second CAN signal, a second power supply signal, a second starting signal (IG signal), third and fourth steering wheel torque signals and a second angle signal, and a PWM three-phase bridge control signal is output to control a second three-phase winding in the six-phase motor. And two paths of steering wheel torque signals input by the first control subsystem 1 and the second control subsystem 2 are used for synchronous verification.

In one embodiment of the present invention, the role flags of the first control subsystem 1 and the second control subsystem 2 are configured by:

presetting role zone bits of the first control subsystem 1 and the second control subsystem 2 so that one of the role zone bits is preset as a master system and the other role zone bit is preset as a slave system;

If the current fault zone bit of the master system is not higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem 1 and the second control subsystem 2 are unchanged;

If the current fault zone bit of the master system is higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem 1 and the second control subsystem 2 are exchanged;

Wherein the light fault is a single point failure fault of a peripheral signal of the redundant electric power steering control system of the autonomous vehicle. The slight fault may be one of a steering wheel torque angle sensor 6 single-path signal fault, a single-path CAN signal fault, a single-path MPS signal fault, a single-path power supply fault, a single-path current sampling fault, and the like.

The catastrophic failure is an internal failure of the central control unit of the first control subsystem 1 or the second control subsystem 2. The serious fault may be one of a single-path component (such as an MCU, a pre-driver, a power chip, a CAN transceiver, a driving axle, etc.) fault of a central control unit of the first control subsystem 1 or the second control subsystem 2, a single three-phase fault of a steering motor, a single-path moment control or angle control fault, an inter-board communication fault, etc.

The ultimate failure is a failure that causes the central control unit of the first control subsystem 1 and/or the second control subsystem 2 to fail in function because of not having normal control. The ultimate fault is one or more of a double-or multi-point failure of a peripheral signal of a redundant electric power steering control system of the autonomous vehicle, a double-or multi-point failure inside a central control unit of the first control subsystem 1 and/or the second control subsystem 2, and a double three-phase fault of the steering motor.

The fault location is determined based on the TAS sensor information, CAN information, MPS information, power supply information, and torque command information collected by the first central control unit 11 and the second central control unit 21 and received by the second central control unit themselves, and if a large error occurs in the signal verification of the same component and the error exceeds a preset error threshold duration time by a preset time threshold, the fault of the corresponding component is determined.

In one embodiment of the invention, the fault flag bits are assigned to distinguish between different fault flag bits and their corresponding fault levels. When the subsystem works normally without faults, the fault flag bit is assigned to 0; when the subsystem has slight faults, the fault flag bit is assigned to be 1; when a subsystem has serious faults, the fault flag bit is assigned to be 2; when the subsystem has ultimate fault, the fault flag bit is assigned to 3.

Determining the role zone bit of the first control subsystem 1 (A system) and the second control subsystem 2 (B system), wherein a value 1 in the role zone bit is a master system, a value 0 in the role zone bit is a slave system, and reconfiguring the role zone bit of the first control subsystem 1 and the second control subsystem 2 by combining the current fault zone bit of the first control subsystem 1 and the second control subsystem 2 specifically comprises the following steps: (1) If the default master-slave flag bit of the A system is 1, the fault flag bit is 0, the default master-slave flag bit of the B system is 0, the A system is a master system, and the B system is a slave system; (2) If the default master-slave flag bit of the A system is 1, the fault flag bit is 0, the default master-slave flag bit of the B system is 0, and the fault flag bit is 1, the A system is a master system, and the B system is a slave system; (3) If the default master-slave flag bit of the A system is 1, the fault flag bit is 1, the default master-slave flag bit of the B system is 0, the A system is a slave system, and the B system is a master system; (4) If the default master-slave flag bit of the A system is 1, the fault flag bit is 1, the default master-slave flag bit of the B system is 0, and the fault flag bit is 1, the A system is a master system, and the B system is a slave system; (5) If the default master-slave flag bit of the A system is 1, the fault flag bit is 0, the default master-slave flag bit of the B system is 0, and the fault flag bit is 2, the A system is a master system, and the B system is a slave system; (6) If the default master-slave flag bit of the A system is 1, the fault flag bit is 2, the default master-slave flag bit of the B system is 0, the A system is a slave system, and the B system is a master system; (7) If the default master-slave flag bit of the A system is 1, the fault flag bit is 0, the default master-slave flag bit of the B system is 0, and the fault flag bit is 3, the A system is a master system, and the B system is a slave system; (8) If the default master-slave flag bit of the A system is 1, the fault flag bit is 3, the default master-slave flag bit of the B system is 0, the A system is a slave system, and the B system is a master system; (9) If A, B system fault zone bits are 2 or 3 at the same time, the system gradually turns off moment output, and the master-slave roles keep a default state; (10) If the default master-slave flag bit of the A system is 0, the fault flag bit is 0, the default master-slave flag bit of the B system is 1, and the fault flag bit is 0, the A system is a slave system, and the B system is a master system; (11) If the default master-slave flag bit of the A system is 0, the fault flag bit is 0, the default master-slave flag bit of the B system is 1, the A system is a master system, and the B system is a slave system; (12) If the default master-slave flag bit of the A system is 0, the fault flag bit is 1, the default master-slave flag bit of the B system is 1, and the fault flag bit is 0, the A system is a slave system, and the B system is a master system; (13) If the default master-slave flag bit of the A system is 0, the fault flag bit is 1, the default master-slave flag bit of the B system is 1, the A system is a slave system, and the B system is a master system; (14) If the default master-slave flag bit of the A system is 0, the fault flag bit is 0, the default master-slave flag bit of the B system is 1, and the fault flag bit is 2, the A system is a master system, and the B system is a slave system; (15) If the default master-slave flag bit of the A system is 0, the fault flag bit is 2, the default master-slave flag bit of the B system is 1, and the fault flag bit is 0, the A system is a slave system, and the B system is a master system; (16) If the default master-slave flag bit of the A system is 0, the fault flag bit is 0, the default master-slave flag bit of the B system is 1, and the fault flag bit is 3, the A system is a master system, and the B system is a slave system; (17) If the default master-slave flag bit of the A system is 0, the fault flag bit is 3, the default master-slave flag bit of the B system is 1, and the fault flag bit is 0, the A system is a slave system, and the B system is a master system.

After determining the role flags of the first control subsystem 1 and the second control subsystem 2 by the method described above, the torque command values allocated to the first control subsystem 1 and the second control subsystem 2 are further determined.

In one embodiment of the invention, the master system has a preset first distribution coefficient f _TrqFac and the slave system has a preset second distribution coefficient 1-f _TrqFac. The first partition coefficient f _TrqFac is preferably 0.5 to 0.65. For example, the first partition coefficient f _TrqFac is 0.5 or 0.6.

For the steering motor 3 described above, which is a six-phase motor with two independent three-phase windings, the first control subsystem 1 and the second control subsystem 2 each control three phases thereof. The torque split ratio of the first control subsystem 1 and the second control subsystem 2 is 50%, i.e. f _TrqFac =0.5. In the event of failure of both subsystems, the first steering torque T ₁ and the second steering torque T ₂, which are determined by the master and slave systems, respectively, are each half of the target steering torque T _DMD of the vehicle.

In this embodiment, if the failure flag bit of the master system is no failure, and the failure flag bits of the slave systems are all slightly failed, the first steering torque T ₁ is T _DMD×f_TrqFac×f_sp, the second steering torque T ₂ is T _DMD×(1-f_TrqFac)_×f_sp, where T _DMD is a target steering torque, f _sp is a power-down protection coefficient, and f _sp is less than 1. If one system fails in single point of peripheral signal (the fault flag bit is 1) and the other system fails in no fault (the fault flag bit is 0), the former system is judged as a master system, the latter system is judged as a slave system, the moment distribution coefficient judged by the master system for the master system and the slave system is f _TrqFacf_sp, namely, the two subsystems are subjected to power-down processing, wherein f _sp is a calibratable power-down protection coefficient, and preferably, the power-down protection coefficient f _sp is not less than 0.6 and not more than 1. For example, the power-down protection coefficient f _sp is 0.8 or 0.9. Taking a preset first distribution coefficient f _TrqFac as 0.5, the power-reducing protection coefficient f _sp as 0.8 as an example, the steering moment determined by the main system and the slave system is 0.4T _DMD, and the maximum output capacity of the system can reach 0.8T _DMD theoretically, namely the whole output proportion of the redundant EPS system is 80%, so that the whole failure rate of the EPS control system is reduced, and the functional safety of the EPS system is improved.

In this embodiment, if the failure flag bit of the master system is no failure and the failure flag bits of the slave systems are all severe failures, the second steering torque T ₂ is 0, and the first steering torque T ₁ satisfies the following formula:

Wherein T _DMD is a target steering torque, and T _MotCap is a maximum steering torque of the steering motor 3. Taking a preset first distribution coefficient f _TrqFac as an example, when the target steering torque T _DMD is not more than half of the maximum steering torque which can be output by the steering device, configuring the full output of the main system without faults, namely the first steering torque T ₁ is; when the target steering torque T _DMD is less than half of the maximum steering torque that the steering motor can output, the first steering torque T ₁ output by the fault-free main system is configured to be the product of the maximum steering torque of the steering motor and the distribution coefficient thereof.

In this embodiment, if the failure flag bit of the master system is a light failure and the failure flag bits of the slave systems are all light failures, the first steering torque T ₁ and the second steering torque T ₂ are both 0. If the fault flag bit of the master system is a slight fault and the fault flag bits of the slave systems are all serious faults, the first steering torque T ₁ and the second steering torque T ₂ are both 0. If the fault flag bits of the master system and the slave system are all severe faults, the first steering torque T ₁ and the second steering torque T ₂ are both 0. If one of the fault flag bits in the master system and the slave system is an ultimate fault, the first steering torque T ₁ and the second steering torque T ₂ are both 0.

In another embodiment of the present invention, if the failure flag of the master system is no failure and the failure flags of the slave systems are all slight failures, the first steering torque T ₁ is T _DMD×f_TrqFac, the second steering torque T ₂ is T _DMD×(1-f_TrqFac)_×f_sp, where T _DMD is a target steering torque, f _sp is a power-down protection coefficient, and f _sp is less than 1. In this embodiment, aiming at no fault of the main system, the slave system is slightly faulty, and only the slightly faulty slave system is subjected to power reduction and assistance treatment, so that the original output capability of the main system is reserved, the overall failure rate of the redundant EPS control system can be further reduced, and the functional safety of the EPS system is improved.

In another embodiment of the present invention, for the failure flag of the master system being no failure, the failure flag of the slave system being a serious failure, the first distribution coefficient f _TrqFac of the master system is not a preset value, but is determined according to the target steering torque T _DMD and the maximum steering torque T _MotCap of the steering motor 3, and the calculation formula of the first distribution coefficient f _TrqFac is as follows:

。

In another embodiment of the present invention, the first distribution coefficient f _TrqFac of the main system is a variable value. Specifically, when both subsystems are working normally, the first distribution coefficient f _TrqFac is 0.5. When there is a fault in one of the two subsystems, the severity of the fault does not result in simultaneous failure of both subsystems, the first partition coefficient f _TrqFac of the main system is configured to be greater than 0.5, such as 0.55 or 0.6. According to the embodiment, the first distribution coefficient of the main system under the fault condition is improved, so that the overall failure rate of the EPS control system can be further redundant, and the functional safety of the EPS system is improved.

In one embodiment of the present invention, a power-assisted control model configured to determine a power-assisted initial torque command according to a steering wheel angle, a hand torque, and a vehicle speed to transmit to the steering motor 3 in a manual driving mode and an angle control model configured to determine a steering initial torque command according to a steering wheel angle and a vehicle speed to transmit to the steering motor 3 in an automatic driving mode are provided in the first control subsystem 1 and the second control subsystem 2.

In one embodiment of the present invention, there is provided a redundant electric power steering control method of an autonomous vehicle for controlling a steering motor of the vehicle using the redundant electric power steering control system of the autonomous vehicle as described above, see fig. 3, the method comprising the steps of.

A first assistance control model and a first angle control model are preset in the first control subsystem 1 (a system in fig. 3), a second assistance control model and a second angle control model are preset in the second control subsystem 2 (B system in fig. 3), the first assistance control model is configured to determine a first assistance initial torque command in a manual driving mode and send the first assistance initial torque command to the steering motor 3, the second assistance control model is configured to determine a second assistance initial torque command in the manual driving mode and send the second assistance initial torque command to the steering motor 3, and the steering motor 3 determines an assistance initial torque required to be output according to the first assistance initial torque command and the second assistance initial torque command received by the second assistance control model. The first angle control model is configured to determine a first steering initial torque command and send it to the steering motor 3 in an automatic driving mode; the second angle control model is configured to determine a second steering initial torque command in an automatic driving mode and send it to the steering motor 3; the steering motor 3 determines the steering initial moment which needs to be output according to the received first steering initial moment instruction and the second steering initial moment instruction.

The first control subsystem 1 and the second control subsystem 2 respectively receive a starting signal, a steering wheel torque signal and an angle signal acquired by a steering wheel torque angle sensor, and a vehicle speed signal and a driving mode signal on a CAN (controller area network) of the whole vehicle. The driving mode signal includes a manual driving mode and an automatic driving mode.

If the driving mode signal is a manual driving mode, the first control subsystem 1 determines a first power-assisted initial moment instruction according to a steering wheel angle, a hand moment and a vehicle speed through the first power-assisted control model and sends the first power-assisted initial moment instruction to the steering motor 3, and the second control subsystem 2 determines a second power-assisted initial moment instruction according to the steering wheel angle, the hand moment and the vehicle speed through the second power-assisted control model and sends the second power-assisted initial moment instruction to the steering motor 3. The steering motor 3 determines the initial power-assisted moment which needs to be output according to the received first initial power-assisted moment command and the second initial power-assisted moment command.

If the driving mode signal is an automatic driving mode, the first control subsystem 1 determines a first steering initial moment instruction according to the steering wheel angle and the vehicle speed through the first angle control model and sends the first steering initial moment instruction to the steering motor 3, and the second control subsystem 2 determines a second steering initial moment instruction according to the steering wheel angle and the vehicle speed through the second angle control model and sends the second steering initial moment instruction to the steering motor 3. The steering motor 3 determines the steering initial moment which needs to be output according to the received first steering initial moment instruction and the second steering initial moment instruction.

The first control subsystem 1 and the second control subsystem 2 detect the fault condition of the system and the fault condition of other components of the redundant electric power steering control system of the automatic driving vehicle, and determine the fault sign of the first control subsystem 1 and the fault sign of the second control subsystem 2 according to the detection result. The first control subsystem 1 and the second control subsystem 2 transmit the role flag bit and the fault flag bit of each other to each other or to an independent controller through inter-board communication.

And determining the role zone bit in the first control subsystem 1 and the second control subsystem 2 at present according to the role zone bit preset by the first control subsystem 1 and the second control subsystem 2 and the fault zone bit thereof. The updating of the role flag bit can be completed by the first control subsystem 1 and the second control subsystem 2 through judgment, or the controller independent of the first control subsystem 1 and the second control subsystem 2 can judge and reconfigure the role flag bit of the first control subsystem 1 and the second control subsystem 2. The current role flags of the first control subsystem 1 and the second control subsystem 2 are determined by the method in the embodiment of the redundant EPS control system, and are not described in detail.

The method comprises the steps of distributing steering torque command values of the first control subsystem 1 and the second control subsystem 2 according to target steering torque during vehicle driving and role zone bits and fault zone bits of the first control subsystem 1 and the second control subsystem 2, wherein the steering torque command values comprise a first steering torque command which is output by a main system to the steering motor 3 and a second steering torque command which is output by a slave system to the steering motor 3, the first steering torque command corresponds to the output first steering torque of the steering motor 3, and the second steering torque command corresponds to the output second steering torque of the steering motor 3.

The first control subsystem 1 judges whether to perform torque protection according to the temperature and the voltage of the first pre-driving unit 12 inside the first control subsystem, and corrects the first steering initial torque command according to the judging result to obtain a protected torque command value. The second control subsystem 1 judges whether to perform torque protection according to the temperature and the voltage of the first pre-driving unit 22 inside the second control subsystem, and corrects the second steering initial torque command according to the judging result to obtain a protected torque command value.

The angle and rotation speed signals of the steering motor are acquired through a motor rotation angle sensor MPS and are transmitted to a central control unit MCU of the first control subsystem 1 and the second control subsystem 2, and the MCU performs current closed-loop control and rotation speed closed-loop control based on a preset motor control model according to the actual phase current and the target phase current of the motor, the actual rotation speed and the target rotation speed and outputs respective three-phase drive axle PWM control signals.

The central control units MCU of the first control subsystem 1 and the second control subsystem 2 transmit respective PWM signals to respective pre-driving units, and the pre-driving units of the two subsystems control the opening or closing of a plurality of MOS tubes in a drive axle module, so that the steering motor outputs corresponding torque, and the steering function of the electric power steering control system is realized.

It should be noted that, in the present invention, the embodiment of the redundant electric power steering control method for an autonomous vehicle and the embodiment of the redundant electric power steering control system for an autonomous vehicle described above belong to the same inventive concept, and all embodiments of the redundant electric power steering control system for an autonomous vehicle are incorporated into the embodiment of the method by reference.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely illustrative of the embodiments of this application and it will be appreciated by those skilled in the art that variations and modifications may be made without departing from the principles of the application, and it is intended to cover all modifications and variations as fall within the scope of the application.

Claims

1. A redundant electric power steering control system for an autonomous vehicle, comprising: the system comprises a first control subsystem (1), a second control subsystem (2) and a steering motor (3), wherein the output ends of the first control subsystem (1) and the second control subsystem (2) are respectively and electrically connected with the steering motor (3);

the first control subsystem (1) and the second control subsystem (2) are configured with different role flags so that one is a master system and the other is a slave system, and the role flags comprise the master system and the slave system;

The first control subsystem (1) and the second control subsystem (2) are further configured with fault zone bits, the fault zone bits comprise no fault, slight fault, serious fault and ultimate fault, the fault zone bits of the first control subsystem (1) are determined according to the operation conditions of the fault zone bits, and the fault zone bits of the second control subsystem (2) are determined according to the operation conditions of the fault zone bits;

Determining a first steering torque instruction output by the main system to the steering motor (3) and a second steering torque instruction output by the auxiliary system to the steering motor (3) according to a target steering torque during running of the vehicle, the role zone bit and the fault zone bit of the first control subsystem (1) and the second control subsystem (2), wherein the first steering torque instruction corresponds to the output first steering torque of the steering motor (3), the second steering torque instruction corresponds to the output second steering torque of the steering motor (3), and the steering torque actually output by the steering motor (3) is the sum of the first steering torque and the second steering torque.

2. Redundant electric power steering control system for autonomous vehicles according to claim 1, characterized by the fact that the role flags of said first (1) and second (2) control subsystem are configured by:

Presetting role zone bits of the first control subsystem (1) and the second control subsystem (2) so that one of the role zone bits is preset as a master system and the other role zone bit is preset as a slave system;

If the current fault zone bit of the master system is not higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem (1) and the second control subsystem (2) are unchanged;

if the current fault zone bit of the master system is higher than the fault zone bit of the slave system, the role zone bits of the first control subsystem (1) and the second control subsystem (2) are exchanged;

3. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein said master system has a preset first split coefficient f _TrqFac and said slave system has a preset second split coefficient 1-f _TrqFac;

4. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein said master system has a preset first split coefficient f _TrqFac and said slave system has a preset second split coefficient 1-f _TrqFac;

5. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein said master system has a preset first split coefficient f _TrqFac and said slave system has a preset second split coefficient 1-f _TrqFac;

6. The redundant electric power steering control system of an autonomous vehicle of claim 4 or 5, wherein the step-down power protection factor f _sp is not less than 0.6 and not more than 1; or alternatively

The power-down protection coefficient f _sp is 0.8 or 0.9.

7. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein said master system has a preset first split coefficient f _TrqFac and said slave system has a preset second split coefficient 1-f _TrqFac;

；

Wherein T _DMD is a target steering torque, and T _MotCap is a maximum steering torque of the steering motor (3).

8. The redundant electric power steering control system of an autonomous vehicle of claim 3 or 4 or 5 or 7, wherein said first split coefficient f _TrqFac is 0.5 to 0.65; or alternatively

The first partition coefficient f _TrqFac is 0.5 or 0.6.

9. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein if the failure flag of the master system is a light failure and the failure flags of the slave systems are both light failures, then the first steering torque T ₁ and the second steering torque T ₂ are both 0; and/or the number of the groups of groups,

10. Redundant electric power steering control system of an autonomous vehicle according to claim 1, characterized in that a power steering control model configured to determine a power steering initial torque command to send to the steering motor (3) as a function of steering wheel angle, hand torque and vehicle speed in manual driving mode and an angle control model configured to determine a steering initial torque command to send to the steering motor (3) as a function of steering wheel angle and vehicle speed in autonomous driving mode are provided within both the first control subsystem (1) and the second control subsystem (2).

11. The redundant electric power steering control system of an autonomous vehicle according to claim 1, characterized in that it further comprises an onboard power supply (4), an overall CAN network (5) and a steering wheel torque angle sensor (6);

The first control subsystem (1) is electrically connected with a vehicle-mounted power supply (4), a whole vehicle CAN network (5) and a steering wheel torque angle sensor (6), wherein the steering wheel torque angle sensor (6) is configured to collect steering wheel torque signals and angle signals and transmit the steering wheel torque signals and angle signals to the first control subsystem (1);

the second control subsystem (2) is electrically connected with the vehicle-mounted power supply (4), the whole vehicle CAN network (5) and the steering wheel torque angle sensor (6) respectively, and the steering wheel torque angle sensor (6) is configured to collect steering wheel torque signals and angle signals and transmit the steering wheel torque signals and angle signals to the second control subsystem (2);

The first control subsystem (1) and the second control subsystem (2) determine a target steering torque of the vehicle according to a steering wheel torque signal and an angle signal.

12. The redundant electric power steering control system of an autonomous vehicle according to claim 11, wherein said first control subsystem (1) comprises a first central control unit (11), a first pre-drive unit (12), a first three-phase drive axle unit (13), a first current sampling unit (14), a first power management unit (15), a first drive axle temperature sensor (16), a first ambient temperature sensor (17), a first correlation breaking unit (18), a first CAN communication unit (19) and a first motor position sensor (110), wherein said first current sampling unit (14) is configured to collect current signals of said steering motor (3), a first drive axle temperature sensor (16) is configured to monitor the temperature of said first three-phase drive axle unit (13), said first ambient temperature sensor (17) is configured to monitor ambient temperature;

The input end of the first central control unit (11) is electrically connected with the signal feedback end of the first pre-driving unit (12), the output end of the first power management unit (15), the output ends of the first drive axle temperature sensor (16) and the steering wheel torque angle sensor (6), the output end of the first environment temperature sensor (17) and the bus port of the first CAN communication unit (19) respectively, and the output ends of the first central control unit and the first environment temperature sensor are electrically connected with the steering motor (3);

The input end of the first pre-driving unit (12) is electrically connected with the output ends of the first central control unit (11) and the first current sampling unit (14) and the signal feedback end of the first three-phase driving bridge unit (13), the output end of the first pre-driving unit is electrically connected with the input end of the first central control unit (11) and the driving input end of the first three-phase driving bridge unit (13), and the first pre-driving unit is configured to drive the first three-phase driving bridge unit (13) to control the working state of the steering motor (3);

The input end of the first three-phase drive axle unit (13) is also electrically connected with the output feedback port of the first correlation breaking unit (18) and the output end of the first current sampling unit (14), and the output end of the first three-phase drive axle unit is electrically connected with the input control port of the first correlation breaking unit (18) and the input end of the first current sampling unit (14) and is configured to control the working state of the steering motor (3);

The input end of the first power management unit (15) is electrically connected with the output end of the first central control unit (11) and the vehicle-mounted power supply (4);

The output end of the first correlation breaking unit (18) is electrically connected with the input end of the steering motor (3) and is configured to switch the connection between the first three-phase drive axle unit (13) and the steering motor (3);

The first central control unit (11) is in communication connection with the whole vehicle CAN network (5) through the first CAN communication unit (19);

the first motor position sensor (110) is configured to monitor a position of a rotor of the steering motor (3) and to transmit position information of the rotor of the steering motor (3) to the first central control unit (11).

13. The redundant electric power steering control system of an autonomous vehicle according to claim 11, wherein said second control subsystem (2) comprises a second central control unit (21), a second pre-drive unit (22), a second three-phase drive axle unit (23), a second current sampling unit (24), a second power management unit (25), a second drive axle temperature sensor (26), a second ambient temperature sensor (27), a second phase shutdown unit (28), a second CAN communication unit (29) and a second motor position sensor (210), wherein said second current sampling unit (24) is configured to collect current signals of said steering motor (3), a second drive axle temperature sensor (26) is configured to monitor the temperature of said second three-phase drive axle unit (23), said second ambient temperature sensor (27) is configured to monitor ambient temperature;

The input end of the second central control unit (21) is electrically connected with the signal feedback end of the second pre-driving unit (22), the output end of the second power management unit (25), the output ends of the second drive axle temperature sensor (26) and the steering wheel torque angle sensor (6), the output end of the second environment temperature sensor (27) and the bus port of the second CAN communication unit (29) respectively, and the output ends of the second central control unit and the second power management unit are electrically connected with the steering motor (3);

The input end of the second pre-driving unit (22) is electrically connected with the output ends of the second central control unit (21) and the second current sampling unit (24) and the signal feedback end of the second three-phase driving axle unit (23), the output end of the second pre-driving unit is electrically connected with the input end of the second central control unit (21) and the driving input end of the second three-phase driving axle unit (23), and the second pre-driving unit is configured to drive the second three-phase driving axle unit (23) to control the working state of the steering motor (3);

The input end of the second three-phase drive axle unit (23) is also electrically connected with the output feedback port of the second phase shutdown unit (28) and the output end of the second current sampling unit (24), and the output end of the second three-phase drive axle unit is electrically connected with the input control port of the second phase shutdown unit (28) and the input end of the second current sampling unit (24) and is configured to control the working state of the steering motor (3);

The input end of the second power management unit (25) is electrically connected with the output end of the second central control unit (21) and the vehicle-mounted power supply (4);

An output of the second phase shutdown unit (28) is electrically connected with an input of the steering motor (3), which is configured to switch control of a connection between a second three-phase drive axle unit (23) and the steering motor (3);

the second central control unit (21) is in communication connection with the whole vehicle CAN network (5) through the second CAN communication unit (29);

The second motor position sensor (210) is configured to monitor a position of a rotor of the steering motor (3) and to transmit position information of the rotor of the steering motor (3) to the second central control unit (21).

14. The redundant electric power steering control system of an autonomous vehicle of claim 1, wherein the light fault is a single point failure fault in a peripheral signal of the redundant electric power steering control system of the autonomous vehicle;

the critical fault is an internal fault of a central control unit of the first control subsystem (1) or the second control subsystem (2);

The ultimate fault is a fault that causes the central control unit of the first control subsystem (1) and/or the second control subsystem (2) to have no normal control and cause functional failure.

15. The redundant electric power steering control system of an autonomous vehicle of claim 14, wherein said light fault is one of a steering wheel torque angle sensor (6) single-pass signal fault, a single-pass CAN signal fault, a single-pass MPS signal fault, a single-pass power supply fault, and a single-pass current sampling fault;

the serious fault is one of a single-path component fault, a single-phase motor three-phase fault, a single-path torque control or angle control fault and an inter-board communication fault of a central control unit of the first control subsystem (1) or the second control subsystem (2);

The final fault is one or more of a peripheral signal double-point or multi-point failure of a redundant electric power steering control system of the automatic driving vehicle, a double-point or multi-point failure inside a central control unit of the first control subsystem (1) and/or the second control subsystem (2), and a double three-phase fault of the motor.

16. A redundant electric power steering control method of an autonomous vehicle, characterized by controlling a motor of the vehicle to control steering of the vehicle using a redundant electric power steering control system of an autonomous vehicle according to any one of claims 1 to 13, the method comprising:

the role zone bits of the first control subsystem (1) and the second control subsystem (2) are preconfigured, so that one is a master system and the other is a slave system;

determining fault zone bits of the first control subsystem (1) and the second control subsystem (2) at present;

Determining the role zone bit in the first control subsystem (1) and the second control subsystem (2) at present according to the role zone bit preset by the first control subsystem (1) and the second control subsystem (2) and the fault zone bit thereof;

According to the target steering torque during the running process of the vehicle and the role zone bit and fault zone bit of the first control subsystem (1) and the second control subsystem (2), the steering torque command values of the first control subsystem (1) and the second control subsystem (2) are distributed, and the method comprises the steps of determining a first steering torque command output by the main system to the steering motor (3) and a second steering torque command output by the main system to the steering motor (3), wherein the first steering torque command corresponds to the output first steering torque of the steering motor (3), and the second steering torque command corresponds to the output second steering torque of the steering motor (3).

17. The method of redundant electric power steering control of an autonomous vehicle of claim 16, further comprising, prior to determining the current role flags of said first (1) and second (2) control subsystems:

-presetting a first assistance control model and a first angle control model within the first control subsystem (1), -presetting a second assistance control model and a second angle control model within a second control subsystem (2), the first assistance control model and the second assistance control model being configured to determine an assistance initial torque command and to send to the steering motor (3) in a manual driving mode, the first angle control model and the second angle control model being configured to determine a steering initial torque command and to send to the steering motor (3) in an automatic driving mode;

The first control subsystem (1) and the second control subsystem (2) respectively receive a starting signal, a steering wheel torque signal and an angle signal acquired by a steering wheel torque angle sensor, and a vehicle speed signal and a driving mode signal;

If the driving mode signal is a manual driving mode, the first control subsystem (1) determines a first power-assisted initial moment instruction according to a steering wheel angle, a hand moment and a vehicle speed through the first power-assisted control model and sends the first power-assisted initial moment instruction to the steering motor (3), and the second control subsystem (2) determines a second power-assisted initial moment instruction according to the steering wheel angle, the hand moment and the vehicle speed through the second power-assisted control model and sends the second power-assisted initial moment instruction to the steering motor (3);

If the driving mode signal is an automatic driving mode, the first control subsystem (1) determines a first steering initial moment instruction through the first angle control model according to the steering wheel angle and the vehicle speed and sends the first steering initial moment instruction to the steering motor (3), and the second control subsystem (2) determines a second steering initial moment instruction through the second angle control model according to the steering wheel angle and the vehicle speed and sends the second steering initial moment instruction to the steering motor (3);

the first control subsystem (1) and the second control subsystem (2) detect the fault condition of the system and the fault condition of other components of the redundant electric power steering control system of the automatic driving vehicle, and determine the fault sign of the first control subsystem (1) as well as the fault sign of the second control subsystem (2) according to the detection result.

18. The method of redundant electric power steering control of an autonomous vehicle according to claim 16, characterized by further comprising, after assigning steering torque command values of said first (1) and second (2) control subsystems:

The first control subsystem (1) judges whether moment protection is carried out according to the temperature and the voltage of the first pre-driving unit (12) in the first control subsystem, and corrects the first steering initial moment instruction according to the judging result, and the second control subsystem (1) judges whether moment protection is carried out according to the temperature and the voltage of the first pre-driving unit (22) in the first control subsystem, and corrects the second steering initial moment instruction according to the judging result.