WO2020125249A1 - 基于线控转向双电机的主动容错和故障缓解***及其控制方法 - Google Patents

基于线控转向双电机的主动容错和故障缓解***及其控制方法 Download PDF

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Publication number
WO2020125249A1
WO2020125249A1 PCT/CN2019/116041 CN2019116041W WO2020125249A1 WO 2020125249 A1 WO2020125249 A1 WO 2020125249A1 CN 2019116041 W CN2019116041 W CN 2019116041W WO 2020125249 A1 WO2020125249 A1 WO 2020125249A1
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Prior art keywords
motor
torque
fault
compensation
yaw rate
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PCT/CN2019/116041
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English (en)
French (fr)
Inventor
赵万忠
王安
***
王春燕
陈莉娟
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南京航空航天大学
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Priority claimed from CN201811549717.6A external-priority patent/CN109733464B/zh
Application filed by 南京航空航天大学 filed Critical 南京航空航天大学
Priority to US17/258,378 priority Critical patent/US20210269087A1/en
Publication of WO2020125249A1 publication Critical patent/WO2020125249A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
    • B62D5/0484—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures for reaction to failures, e.g. limp home
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D15/00—Steering not otherwise provided for
    • B62D15/02—Steering position indicators ; Steering position determination; Steering aids
    • B62D15/021—Determination of steering angle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D3/00—Steering gears
    • B62D3/02—Steering gears mechanical
    • B62D3/12—Steering gears mechanical of rack-and-pinion type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/001—Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
    • B62D5/005—Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup means for generating torque on steering wheel or input member, e.g. feedback
    • B62D5/006—Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup means for generating torque on steering wheel or input member, e.g. feedback power actuated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0421—Electric motor acting on or near steering gear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
    • B62D5/0487—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures detecting motor faults
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/008—Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures

Definitions

  • the invention relates to the technical field of wire-controlled steering systems and fault-tolerant control systems, in particular to the function of switching working modes under different fault conditions of the wire-controlled steering dual motors, and to ensure good car driving performance and endurance.
  • System and its mode switching control method are known in the art.
  • a single active fault tolerance method cannot solve the problem of actuator failure.
  • a single hardware redundancy method or a combination of hardware redundancy and active fault tolerance method cannot solve the real-time optimization problem of automobile driving, which will cause the waste of faulty actuator resources.
  • the present invention proposes a new fault tolerance concept-fault mitigation, and based on this concept, it provides an active fault tolerance and fault link system and its mode based on the steering-by-wire dual-execution motor Switching method, on the basis of ensuring safety, through the combination of hardware redundancy and active fault tolerance and fault mitigation, the system's safety, reliability, and real-time superiority in performance are greatly improved, and the automobile is realized.
  • the perfect integration of safety and reliability solves the problem that the car cannot run or the performance drops sharply in the case of a single motor failure, and solves the problem of hardware redundancy and active fault tolerance technology that directly isolates the faulty motor, which is caused by too conservative methods.
  • the problem of wasted motor performance also solves the problem that the real-time optimized performance of the car cannot be achieved according to the type of car failure during the driving process.
  • the present invention provides an active fault tolerance and fault mitigation system based on a dual-motor with steering by wire.
  • the system includes: an acquisition unit, a steering wheel assembly, an ECU control module, and a dual-machine execution unit;
  • the acquisition unit is connected to the ECU control module, the steering wheel assembly, and the dual-machine execution unit; the acquisition unit includes a steering wheel angle sensor 4, a steering wheel torque sensor 5, a front wheel angle sensor 9, a front wheel torque sensor 12, The vehicle speed sensor 19, the yaw rate sensor collects the status of the vehicle; and transmits the collected signals or instructions to the ECU control module, steering wheel assembly, and dual-machine execution unit, specifically: the collection unit will drive the vehicle in real time In the process, the vehicle speed signal, the steering wheel angle signal, the rotation speed sensor obtains the rotation motor's rotation angle signal, the torque sensor obtains the torque motor's torque signal, and the vehicle's yaw rate signal obtained by the yaw rate sensor, the steering wheel's rotation angle signal, etc It is sent to the electronic control unit and the yaw rate calculation unit; the resistance, voltage, and current signals of the corner motor and torque motor are sent to the motor fault diagnosis unit; the instructions sent by the fault diagnosis unit are passed to the fault-tolerant control strategy unit
  • the ECU control module is connected to the acquisition unit, the dual-machine execution unit, and the steering wheel assembly, which mainly includes an arithmetic controller 7 and a fault-tolerant controller 18.
  • the arithmetic controller 7 includes a motor fault diagnosis unit and an electronic control unit;
  • the fault-tolerant controller 18 Fault-tolerant controller, including fault-tolerant control strategy unit, yaw rate calculation unit, stability control unit, dual-motor fault-tolerant compensation unit;
  • the ECU control module receives the signal from the acquisition unit, and after calculation, transmits the corresponding instructions to the dual-machine execution unit for action; specifically, the motor fault diagnosis unit is an adaptive Kalman filter to implement the corner motor and torque motor On-line identification of resistance, current, and voltage. It determines the state of the motor based on the real-time resistance, current, and voltage signals of the corner motor and torque motor transmitted by the acquisition unit, and transmits the actual voltage and current signals of the motor to the fault-tolerant controller.
  • the motor fault diagnosis unit is an adaptive Kalman filter to implement the corner motor and torque motor On-line identification of resistance, current, and voltage. It determines the state of the motor based on the real-time resistance, current, and voltage signals of the corner motor and torque motor transmitted by the acquisition unit, and transmits the actual voltage and current signals of the motor to the fault-tolerant controller.
  • the fault-tolerant controller carries out the corresponding fault-tolerant compensation control strategy for active fault tolerance and fault mitigation for different motor faults according to the signals transmitted by the motor fault diagnosis unit;
  • the signal calculates the ideal yaw rate signal, and then calculates the desired yaw rate difference according to the ideal yaw rate signal and the actual yaw rate signal, and transmits the yaw rate difference to the stability control Unit; the stability control unit comprehensively considers the influence of road surface disturbance, lateral wind, system friction, etc.
  • the compensation torque is obtained and transmitted to the dual-machine fault-tolerant compensation unit; the dual-machine fault-tolerant compensation unit receives the compensation torque signal transmitted by the stability control unit, and according to the fault-tolerant strategy of the fault-tolerant control strategy unit, through the torque motor controller 16 controls the action of the torque motor 13 to compensate the system, thereby achieving active fault tolerance or fault mitigation.
  • the steering wheel assembly includes a steering wheel 1, a steering column 2, a road sensor motor 3, a road sensor motor controller 6, a steering wheel 1 is connected to a road sensor motor 3 and a steering wheel angle sensor 4 through a steering column 2
  • the torque sensor 5 is installed on the steering column 2; the road sensor motor controller 6 connects the road sensor motor 3 and the steering wheel torque sensor 5 to control the operation of the road sensor motor 3.
  • the dual-machine execution unit includes a corner motor controller 8, a corner motor 10, a bipolar reducer 11, a torque motor controller 16, a torque motor 13, a reducer 14, a rack and pinion mechanism 15, and a front wheel 17 connected in sequence;
  • the angle motor 10 and the torque motor 13 and the bipolar reducer 11, the reducer 14 are connected to the rack and pinion steering gear 15, the front wheels 17 are installed on both sides of the rack and pinion steering gear 15, and the front wheel angle sensor 9 is installed with On the front wheel 17, the corner sensor 9 and the front wheel torque sensor 12 are connected to the Flexray bus, and the signals of the corner motor controller 8 and the torque motor controller 16 are input to the bus, and then transmitted to the fault-tolerant controller 18 through the bus;
  • the corner motor 10 and its reduction mechanism 11 are connected to the corner control unit 8, the corner motor control unit 8 controls the operation of the corner motor 10 and the bipolar reducer 11, the torque motor 13 and the reducer 14 are connected to the torque motor controller 16, and the torque motor control The controller 16 controls the operation of the torque motor 13 and
  • the present invention also provides a mode switching control method based on the active fault-tolerant and fault mitigation system of the above-mentioned wire-steering dual-motor.
  • the method includes the following steps:
  • Step 1 While the car is traveling, the acquisition unit transmits the corner motor R 2 and the torque motor resistance R 3 , and the current signals I 2 and I 3 to the motor fault diagnosis unit.
  • Step 2 The fault-tolerant control strategy unit receives the diagnosis result from the fault diagnosis unit, obtains the operating condition of the corner motor or torque motor, and compares the corner motor voltage U 2 and the torque motor voltage U 3 with the reference threshold U 0 , Decide to adopt active fault tolerance strategy 1, or active fault tolerance strategy 2, or fault mitigation strategy 1, or fault mitigation strategy 2;
  • Step 3 The yaw rate calculation unit calculates the real-time ideal yaw rate signal ⁇ r * based on the steering wheel angle signal ⁇ sw collected by the acquisition unit in real time, and the vehicle speed signal u according to the variable transmission ratio law, and then based on the ideal yaw rate signal ⁇ r * and the actual yaw rate signal ⁇ r calculate the desired yaw rate difference ⁇ r to be adjusted, and transmit the yaw rate difference ⁇ r to the stability control unit;
  • the yaw rate calculation unit inputs the vehicle's steering two-degree-of-freedom model based on the real-time vehicle speed u and the front wheel angle to obtain the actual yaw rate ⁇ r .
  • Step 4 The stability control unit receives the yaw rate difference ⁇ r input from the yaw rate control unit, and converts it into the corresponding compensation torque T 1 , the compensation torque T 2 formed by comprehensive road surface interference, and the compensation caused by the system friction Torque T 3 , taking into account the system stability control factors, using ⁇ integrated robust controller control, improve the system's ability to resist external interference, and transfer the compensation torque ⁇ T to the two-unit compensation unit;
  • ⁇ T makes the total compensation torque
  • ⁇ T 1 makes the compensation torque needed to make up the yaw rate difference
  • ⁇ T 2 makes the compensation torque caused by road disturbance
  • ⁇ T 3 makes the compensation torque caused by the system friction
  • Step 5 The fault-tolerant controller receives the compensation torque T from the stability control unit, selects the corresponding compensation strategy by receiving the fault-tolerant strategy from the fault-tolerant controller, and acts on the dual-machine execution unit and steering wheel assembly to ensure The car can have good yaw rate control effect and better stability.
  • step 1 a motor fault diagnosis unit in step 1, which can be designed by an adaptive Kalman filter Realize on-line identification of resistance, current and voltage of corner motor and torque motor:
  • x(k) Ax(k-1)+B(u(k)+w(k)) (4)
  • the system state at time k at x(k), the system state at time k-1 at x(k-1), A and B are system parameters, and u(k) is time k
  • w(k) is the process noise signal
  • v(k) is the measurement noise signal
  • y v (k) is the measured value of the system at time k
  • C is the matrix
  • the system state at time k at x(k), the system state at time k-1 at x(k-1), A, B, R are system parameters
  • C is a matrix
  • a T Is the transposed matrix of the A matrix
  • B T is the transposed matrix of the B matrix
  • C T is the transposed matrix of the C matrix
  • y e (k) is the output signal modified by the Kalman filter
  • P(k) is The covariance of the system at time k
  • P(k-1) is the covariance of the system at time k-1
  • En is the unit vector
  • Mn(k) is the intermediate variable
  • Equation (11) errcov(k) is the covariance of the system error, C is the matrix, C T is the transposed matrix of the C matrix, and P(k) is the covariance of the system at time k.
  • L is the torque motor inductance
  • R 3 is the torque motor resistance
  • k b3 is the electromotive force constant
  • u 3 is the input voltage of the torque motor
  • i a3 is the current of the torque motor
  • Is the angular acceleration of the torque motor
  • k b3 is the rigidity of the angular motor.
  • the adaptive Kalman filter transmits the voltage, current, and resistance signals of the corner motor and torque motor to the fault-tolerant control strategy unit.
  • active fault tolerance strategy 1, or active fault tolerance strategy 2, or fault mitigation strategy 1, or fault mitigation strategy 2 includes:
  • Step 2.1 The Kalman filter can determine that the corner motor or torque motor is faulty by monitoring the resistance fluctuation beyond the normal range.
  • the fault-tolerant strategy adopted in Step 2 includes:
  • m rack is the mass of the rack
  • y rack is the displacement of the rack
  • r L is the offset of the main pin
  • K L is the rigidity of the steering rod
  • B rack is the rack damping coefficient
  • F frrack is the inter-system Friction force
  • G is the reduction ratio of the double reducer mechanism
  • T g2 is the output torque of the steering motor 2
  • T g3 is the output torque of the steering motor 3
  • J w is the moment of inertia of the front wheel
  • T frkp is the friction torque
  • B kp is the damping coefficient of the kingpin.
  • the system carries out the fault mitigation strategy 1.
  • the corner motor mainly controls the vehicle yaw rate, and the torque motor compensates the compensation torque ⁇ T 1 returned by the yaw rate controller;
  • T 11 is the compensation torque required to compensate for the yaw rate difference
  • T 21 is the compensation torque caused by road disturbances
  • T 31 is the friction torque caused by the system friction
  • the fault mitigation strategy 2 is adopted.
  • the torque motor functions as the corner motor for main control, and the corner motor functions as the torque motor to compensate the compensation torque returned by the yaw rate controller ⁇ T 2 ;
  • T 12 is the compensation torque required to compensate for the yaw rate difference
  • T 22 is the compensation torque caused by road disturbances
  • T 32 is the compensation torque caused by the friction of the system
  • the active fault tolerance strategy 1 is used to cut off the torque motor current input and the corner motor is controlled separately to compensate the compensation torque ⁇ T 3 returned by the yaw rate controller;
  • ⁇ T 3 ⁇ T 13 + ⁇ T 23 + ⁇ T 33 (20)
  • ⁇ T 3 makes the total compensation torque
  • T 13 makes the compensation torque needed to make up the difference of yaw rate
  • T 23 makes the compensation torque caused by the road disturbance
  • T 33 makes the compensation torque caused by the friction of the system
  • ⁇ T 4 ⁇ T 14 + ⁇ T 24 + ⁇ T 34 (22)
  • ⁇ T 4 makes the total compensation torque
  • T 14 makes the compensation torque needed to make up the difference of yaw rate
  • T 24 makes the compensation torque caused by road disturbance
  • T 34 makes the compensation torque caused by the friction of the system
  • control framework of the ⁇ integrated robust controller includes:
  • the comprehensive robust controller must be able to quickly track the difference between the ideal yaw rate and the actual yaw rate under different fault-tolerant strategies, and it must have a good interference suppression for external disturbances such as ground disturbances and lateral wind disturbances, or Output the corresponding compensation torque and transmit the compensation torque ⁇ T to the dual-unit compensation unit;
  • ⁇ T is the total compensation torque
  • ⁇ T 1 is the compensation torque required to compensate for the yaw rate difference
  • ⁇ T 2 is the compensation torque due to road disturbances
  • ⁇ T 3 is the compensation torque due to system friction.
  • the fault-tolerant concept of fault mitigation is proposed relative to the traditional fault-tolerant concept.
  • the traditional research idea is to use hardware redundancy or software redundancy.
  • Hardware redundancy considers replacing the failed hardware with new hardware, separating the error hardware from the system, or using software redundancy.
  • Replace the hardware redundancy with software redundancy and calculate the data from other sensors or actuators through derivation to replace the data of the failed component. In the actual process, this is a more conservative fault-tolerant method, which is essentially a substitution relationship. Replace the faulty component with a new component, and replace the wrong data with other data.
  • the car can be called "disease-free work.”
  • the remaining functions of the faulty parts are not fully developed and wasted, and for example, the motor is not completely paralyzed after a fault. It is possible to use some functions to output a certain torque.
  • the faulty motor can be taken at the same time as the normal motor. Work, the car at this time can be called "work with illness”.
  • This application realizes real-time optimal control of automobiles through matching and comparison of faulty motors and normal motors. At the same time, it can ensure the car's better working ability and performance in extreme wild environments, and also provides a guarantee for the car to repair at the most advanced maintenance point.
  • FIG. 1 is a schematic diagram of the structural arrangement of a dual-motor steering-by-wire system of the present invention.
  • FIG. 2 is a schematic diagram of a control device of an active fault tolerance and fault mitigation fault tolerance system for a dual-motor steering-by-wire according to the present invention.
  • FIG. 3 is a general diagram of the control strategy of the active fault tolerance and fault mitigation fault tolerance system of the dual-motor steering-by-wire system of the present invention.
  • Fig. 4 is a block diagram of a vehicle stability control system with a fault-tolerant steer-by-wire dual-motor vehicle based on yaw rate feedback.
  • a layout diagram of an active fault-tolerant and fault mitigation system based on a steering-by-wire dual motor of the present invention on a vehicle body includes: an acquisition unit, a steering wheel assembly, and an ECU control module (model MT20U2, in specific In the implementation, you can also use M7 or MT20U), dual-machine execution unit;
  • the acquisition unit is connected to the ECU control module, the steering wheel assembly, and the dual-machine execution unit; the acquisition unit includes a steering wheel angle sensor 4, a steering wheel torque sensor 5, a front wheel angle sensor 9, a front wheel torque sensor 12, a vehicle speed sensor 19.
  • the yaw rate sensor and other sensors that collect the state of the vehicle obtains in real time the vehicle speed signal, steering wheel angle signal, speed sensor to obtain the rotation signal of the steering motor, and the torque sensor to obtain the torque signal of the torque motor and
  • the yaw rate signal obtained by the yaw rate sensor and the turn signal of the steering front wheel are transmitted to the electronic control unit and the yaw rate calculation unit;
  • the resistance, voltage and current signals of the corner motor and torque motor are sent to the motor fault diagnosis Unit;
  • the instructions sent by the fault diagnosis unit are transmitted to the fault-tolerant control strategy unit;
  • the difference between the ideal yaw rate and the actual yaw rate obtained by the yaw rate calculation unit and the road surface interference side wind interference signal are sent to the two machines Fault tolerance compensation control unit;
  • the ECU control module is connected to the acquisition unit, the dual-machine execution unit, and the steering wheel assembly, which mainly includes an arithmetic controller 7 and a fault-tolerant controller 18.
  • the arithmetic controller 7 includes a motor fault diagnosis unit and an electronic control unit;
  • the fault-tolerant controller 18 is Fault-tolerant controller, including fault-tolerant control strategy unit, yaw rate calculation unit, stability control unit, dual-motor fault-tolerant compensation unit;
  • the ECU control module receives the signal from the acquisition unit, and after calculation, transmits the corresponding instructions to the dual-machine execution unit for action; specifically, the motor fault diagnosis unit is an adaptive Kalman filter to implement the corner motor and torque motor On-line identification of resistance, current, and voltage. It determines the state of the motor based on the real-time resistance, current, and voltage signals of the corner motor and torque motor transmitted by the acquisition unit, and transmits the actual voltage and current signals of the motor to the fault-tolerant controller.
  • the motor fault diagnosis unit is an adaptive Kalman filter to implement the corner motor and torque motor On-line identification of resistance, current, and voltage. It determines the state of the motor based on the real-time resistance, current, and voltage signals of the corner motor and torque motor transmitted by the acquisition unit, and transmits the actual voltage and current signals of the motor to the fault-tolerant controller.
  • the fault-tolerant controller carries out the corresponding fault-tolerant compensation control strategy for active fault tolerance and fault mitigation for different motor faults according to the signals transmitted by the motor fault diagnosis unit;
  • the signal calculates the ideal yaw rate signal, and then calculates the desired yaw rate difference according to the ideal yaw rate signal and the actual yaw rate signal, and transmits the yaw rate difference to the stability control Unit; the stability control unit comprehensively considers the influence of road surface disturbance, lateral wind, system friction, etc.
  • the compensation torque is obtained and transmitted to the dual-machine fault-tolerant compensation unit; the dual-machine fault-tolerant compensation unit receives the compensation torque signal transmitted by the stability control unit, and according to the fault-tolerant strategy of the fault-tolerant control strategy unit, through the torque motor controller 16 controls the action of the torque motor 13 to compensate the system, thereby achieving active fault tolerance or fault mitigation.
  • the steering wheel assembly is connected to the acquisition unit and the ECU control module respectively.
  • the steering wheel assembly includes a steering wheel 1, a steering column 2, a road-sensing motor 3, a road-sensing motor controller 6, and the steering wheel 1 is connected to the steering column 2
  • the road sensor motor 3 and its steering wheel angle sensor 4 are connected, and the steering wheel torque sensor 5 is installed on the steering column 2; the road sensor motor controller 6 connects the road sensor motor 3 and the steering wheel torque sensor 5 to control the road sensor motor 3 Running.
  • the dual-machine execution unit is connected to the acquisition unit and the ECU control module respectively.
  • the dual-machine execution unit includes a corner motor controller 8, a corner motor 10, a bipolar reducer 11, a torque motor controller 16, and a torque motor that are sequentially connected 13, reducer 14, gear rack mechanism 15, front wheel 17; corner motor 10 and torque motor 13 and bipolar reducer 11, reducer 14 is connected to the rack and pinion steering gear 15, the front wheel 17 is mounted on the gear On both sides of the rack steering gear 15, the front wheel angle sensor 9 is installed on the front wheel 17, the angle sensor 9 and the front wheel torque sensor 12 are connected to the Flexray bus, and the signals of the corner motor controller 8 and the torque motor controller 16 are input to In the bus, and then transmitted to the fault-tolerant controller 18 through the bus; the corner motor 10 and its speed reduction mechanism 11 are connected to the corner control unit 8, the corner motor control unit 8 controls the operation of the corner motor 10 and the bipolar speed reducer 11, the torque motor 13
  • the speed reducer 14 is connected to the torque motor controller 16, and the torque motor controller
  • FIGS 2 and 3 are the schematic diagram of the control device for the active fault tolerance and fault mitigation fault tolerance system of the dual-motor with steering-by-wire and the general diagram of the control strategy of the active fault tolerance and fault mitigation fault-tolerance system with the steering-by-wire dual motor.
  • the control flow of the present invention is as follows:
  • Step 1 While the car is traveling, the acquisition unit transmits the corner motor R 2 and the torque motor resistance R 3 , and the current signals I 2 and I 3 to the motor fault diagnosis unit.
  • the motor fault diagnosis unit includes an adaptive Kalman filter to realize the online identification of the resistance, current and voltage of the corner motor and torque motor:
  • x(k) Ax(k-1)+B(u(k)+w(k)) (4)
  • the system state at time k at x(k), the system state at time k-1 at x(k-1), A and B are system parameters, and u(k) is time k
  • w(k) is the process noise signal
  • v(k) is the measurement noise signal
  • y v (k) is the measured value of the system at time k
  • C is the matrix
  • the system state at time k at x(k), the system state at time k-1 at x(k-1), A, B, R are system parameters
  • C is matrix
  • B T is the transposed matrix of the B matrix
  • C T is the transposed matrix of the C matrix
  • y e (k) is the output signal modified by the Kalman filter
  • P(k) is The covariance of the system at time k
  • P(k-1) is the covariance of the system at time k-1
  • En is the unit vector
  • Mn(k) is the intermediate variable
  • Equation (11) errcov(k) is the covariance of the system error, C is the matrix, C T is the transposed matrix of the C matrix, and P(k) is the covariance of the system at time k.
  • L is the torque motor inductance
  • R 3 is the torque motor resistance
  • k b3 is the electromotive force constant
  • u 3 is the input voltage of the torque motor, Is the current of the torque motor, Is the angular acceleration of the torque motor
  • k b3 is the rigidity of the angular motor
  • Step 2 The fault-tolerant control strategy unit receives the diagnosis result from the fault diagnosis unit, obtains the operating condition of the corner motor or torque motor, and compares the corner motor voltage U 2 and the torque motor voltage U 3 with the reference threshold U 0 , Decide to adopt active fault tolerance strategy 1, or active fault tolerance strategy 2, or fault mitigation strategy 1, or fault mitigation strategy 2;
  • the process of the above active fault tolerance strategy 1, or active fault tolerance strategy 2, or fault mitigation strategy 1, or fault mitigation strategy 2 includes:
  • Step 2.1 The Kalman filter can determine that the corner motor or torque motor is faulty by monitoring the resistance fluctuation beyond the normal range.
  • the fault-tolerant strategy adopted in Step 2 includes:
  • m rack is the mass of the rack
  • y rack is the displacement of the rack
  • r L is the offset of the main pin
  • K L is the rigidity of the steering rod
  • B rack is the rack damping coefficient
  • F frrack is the inter-system Friction force
  • G is the reduction ratio of the double reducer mechanism
  • T g2 is the output torque of the steering motor 2
  • T g3 is the output torque of the steering motor 3
  • J w is the moment of inertia of the front wheel
  • T frkp is the friction torque
  • B kp is the damping coefficient of the kingpin.
  • the system carries out the fault mitigation strategy 1.
  • the corner motor mainly controls the vehicle yaw rate, and the torque motor compensates the compensation torque ⁇ T 1 returned by the yaw rate controller;
  • T 11 is the compensation torque required to compensate for the yaw rate difference
  • T 21 is the compensation torque caused by road disturbances
  • T 31 is the friction torque caused by the system friction
  • the fault mitigation strategy 2 is adopted.
  • the torque motor functions as the corner motor for main control, and the corner motor functions as the torque motor to compensate the compensation torque returned by the yaw rate controller ⁇ T 2;
  • T 12 is the compensation torque required to compensate for the yaw rate difference
  • T 22 is the compensation torque caused by road disturbances
  • T 32 is the compensation torque caused by the friction of the system
  • the active fault tolerance strategy 1 is used to cut off the torque motor current input and the corner motor is controlled separately to compensate the compensation torque ⁇ T 3 returned by the yaw rate controller;
  • ⁇ T 3 ⁇ T 13 + ⁇ T 23 + ⁇ T 33 (20)
  • ⁇ T 3 makes the total compensation torque
  • T 13 makes the compensation torque needed to make up the difference of yaw rate
  • T 23 makes the compensation torque caused by the road disturbance
  • T 33 makes the compensation torque caused by the friction of the system
  • ⁇ T 4 ⁇ T 14 + ⁇ T 24 + ⁇ T 34 (22)
  • ⁇ T 4 makes the total compensation torque
  • T 14 makes the compensation torque needed to make up the difference of yaw rate
  • T 24 makes the compensation torque caused by road disturbance
  • T 34 makes the compensation torque caused by the friction of the system
  • step 4 the control framework of the ⁇ integrated robust controller is shown in FIG. 4, and in FIG. 4, K
  • the disturbance input ⁇ r * of the system is the ideal yaw rate
  • the disturbance input is the ideal front wheel rotation angle ⁇ f *
  • the lateral wind disturbance F v and the disturbance torques of the road surface T r , W 1 , W 2 are
  • the weighting function is usually set as a high-pass filter.
  • W d is the interference weighting matrix
  • ⁇ G is the perturbation of unknown parameters
  • ⁇ I is the compensation current
  • z 1 and z 2 are the evaluation outputs.
  • control framework of the ⁇ integrated robust controller includes:
  • the comprehensive robust controller must be able to quickly track the difference between the ideal yaw rate and the actual yaw rate under different fault-tolerant strategies, and it must have a good interference suppression for external disturbances such as ground disturbances and lateral wind disturbances, or Output the corresponding compensation torque and transmit the compensation torque ⁇ T to the dual-unit compensation unit;
  • ⁇ T is the total compensation torque
  • ⁇ T 1 is the compensation torque required to compensate for the yaw rate difference
  • ⁇ T 2 is the compensation torque due to road disturbances
  • ⁇ T 3 is the compensation torque due to system friction
  • Step 3 The yaw rate calculation unit calculates the real-time ideal yaw rate signal ⁇ r * based on the steering wheel angle signal ⁇ sw collected by the acquisition unit in real time, and the vehicle speed signal u according to the variable transmission ratio law, and then based on the ideal yaw rate signal ⁇ r * and the actual yaw rate signal ⁇ r calculate the desired yaw rate difference ⁇ r to be adjusted, and transmit the yaw rate difference ⁇ r to the stability control unit;
  • the yaw rate calculation unit inputs the vehicle's steering two-degree-of-freedom model based on the real-time vehicle speed u and the front wheel angle to obtain the actual yaw rate ⁇ r .
  • Step 4 The stability control unit receives the yaw rate difference ⁇ r input from the yaw rate control unit, and converts it into the corresponding compensation torque T 1 , the compensation torque T 2 formed by comprehensive road surface interference, and the compensation caused by the system friction Torque T 3 , taking into account the system stability control factors, using ⁇ integrated robust controller control, improve the system's ability to resist external interference, and transfer the compensation torque ⁇ T to the two-unit compensation unit;
  • ⁇ T makes the total compensation torque
  • ⁇ T 1 makes the compensation torque needed to make up the yaw rate difference
  • ⁇ T 2 makes the compensation torque caused by road disturbance
  • ⁇ T 3 makes the compensation torque caused by the system friction
  • Step 5 The fault-tolerant controller receives the compensation torque T from the stability control unit, selects the corresponding compensation strategy by receiving the fault-tolerant strategy from the fault-tolerant controller, and acts on the rack mechanism to ensure that the car can have a good horizontal Swing angle speed control effect, and better stability.

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Abstract

一种基于线控转向双电机的主动容错和故障缓解***及其模式切换控制方法，该***包含依次连接的采集单元、转向盘总成、ECU控制模块、前轮转向总成和容错控制器（18）；采集单元将采集到的汽车信号传递给ECU控制模块，再通过容错控制策略单元、横摆角速度计算单元、稳定性控制单元、双机补偿单元，选取对应的补偿策略，作用于齿轮齿条机构（15）；该***和方法可以依据故障电机（10、13）不同的故障工况，在主动容错及故障缓解模式中进行切换，实现汽车实时性能的最优控制，从而保证汽车在野外故障条件下的行驶性和较高的性能。

Description

基于线控转向双电机的主动容错和故障缓解***及其控制方法 技术领域
本发明涉及线控转向***及容错控制***技术领域，特别是在依据线控转向双电机不同故障工况下切换工作模式功能，并保证良好的汽车行驶性能和续航能力的线控转向双电机容错***及其模式切换控制方法。
背景技术
目前,关于汽车故障容错普遍采用硬件冗余和软件冗余两种方式。其中硬件冗余可以在汽车发生故障的时候采取替换的方式，用新的硬件替换掉故障的硬件，以此保证汽车的正常行驶；但硬件冗余方式将加大汽车的经济成本，没有考虑汽车实时的故障状况，不能实现汽车实时最优分配，是一种较为保守的容错方式。软件冗余是一种以软件冗余来减少硬件冗余开发成本的方式，软件冗余的核心方式是主动容错的方式，该方式通过其他组正确数据的辨识及推导，用推导出的近似正确的数据替换掉因传感器等失效测得的错误数据，这样可以解决因为某些传感器失效带来的连锁误差，可大大减少容错的开发成本。但有些执行器不适合完全用主动容错的方式替代，因为有些执行器的故障，不仅仅会造成数据的错误，更会直接影响汽车的执行效果。比如汽车线控转向的执行电机，单转向执行电机发生故障，只采用主动容错的方式无法替代转向电机失效带来的转向影响，不能保证野外工况下唯一执行器转向执行电机发生故障，汽车的正常行驶和最优控制。
单独的主动容错方式无法解决执行器故障问题，单独的硬件冗余方式或硬件冗余与主动容错方式结合无法解决汽车行驶实时最优化问题，会造成故障执行器资源的浪费。
发明内容
针对现有容错理念及现有技术的不足，本发明提出了一种新型容错理念-故障缓解，并基于此理念提供了一种基于线控转向双执行电机的主动容错和故障环节***及其模式切换方法，在保证安全性的基础上，通过硬件冗余和主动容错及故障缓解三者相结合的方式极大的提高了***的安全性、可靠性、以及性能的实时优越性，实现了汽车安全性与可靠性完美的融合，解决了在单电机故障的情况下，汽车无法运行或者性能急剧下降的问题，解决了硬件冗余与主动容错技术直接隔离故障电机，因方式过于保守造成的故障电机性能浪费的问题，更解决了汽车行驶过程中不能依据汽车故障类型实现汽车实时最优化性能的问题。
本发明是通过如下技术方案实现的：
首先，本发明提供了一种基于线控转向双电机的主动容错和故障缓解***，该***包括： 采集单元、转向盘总成、ECU控制模块、双机执行单元；
其中，采集单元分别与ECU控制模块、转向盘总成、双机执行单元连接；所述采集单元包括转向盘转角传感器4，转向盘力矩传感器5，前轮转角传感器9，前轮力矩传感器12，车速传感器19，横摆角速度传感器采集汽车状态的传感器；并将采集到的信号或指令分别转递给ECU控制模块、转向盘总成、双机执行单元，具体而言：采集单元实时将汽车行驶过程中车速信号、转向盘转角信号、转速传感器获得转向电机的转角信号、转矩传感器获得转矩电机的转矩信号以及横摆角速度传感器获得的汽车横摆角速度信号、转向前轮的转角信号等传给电子控制单元及横摆角速度计算单元；将转角电机与转矩电机的电阻、电压、电流信号发送给电机故障诊断单元；将故障诊断单元发送的指令传递给容错控制策略单元；将横摆角速度计算单元得出的理想横摆角速度与实际横摆角速度差值信号及路面干扰侧向风干扰等信号发送给双机容错补偿控制单元；
ECU控制模块分别与采集单元、双机执行单元、转向盘总成连接，其主要包括运算控制器7和容错控制器18，运算控制器7包括电机故障诊断单元、电子控制单元；容错控制器18即容错控制器，包括容错控制策略单元，横摆角速度计算单元，稳定性控制单元，双电机容错补偿单元；
ECU控制模块接收来自采集单元的信号，经过计算后把相应的指令传输给双机执行单元进行动作；具体而言，电机故障诊断单元为自适应的Kalman滤波器，以实现转角电机和转矩电机电阻，电流，电压的在线辨识，其根据采集单元传送的转角电机与转矩电机实时的电阻、电流、电压信号，判定电机的状态，并将电机的实际电压，电流信号传递给容错控制器。
容错控制器根据电机故障诊断单元传来的信号，对于不同的电机故障，通过主动容错及故障缓解的方式进行相应的容错补偿控制策略；横摆角速度计算单元根据采集单元传送的方向盘转角信号、车速信号计算出理想的横摆角速度信号，再根据理想的横摆角速度信号与实际的横摆角速度信号计算出所需调整的理想横摆角速度差值，并把横摆角速度差值传递给稳定性控制单元；稳定性控制单元根据横摆角速度计算单元传递的横摆角速度差值综合考虑路面干扰，侧向风，***摩擦等对汽车稳定的影响，从***鲁棒性出发，以保证汽车的稳定性为前提，得出补偿转矩并传递给双机容错补偿单元；双机容错补偿单元接收稳定性控制单元传递的补偿转矩信号,并且根据容错控制策略单元的容错策略，通过转矩电机控制器16控制转矩电机13动作，对***进行补偿，从而实现故障的主动容错或故障缓解。
转向盘总成包括转向盘1、转向柱2、路感电机3,路感电机控制器6,转向盘1通过转向杆柱2与路感电机3及其转向盘转角传感器4相连接，转向盘力矩传感器5安装在转向杆柱 2上；路感电机控制器6连接路感电机3及转向盘力矩传感器5，控制路感电机3的运行。
双机执行单元包括依次连接的转角电机控制器8，转角电机10，双极减速器11，转矩电机控制器16，转矩电机13，减速器14，齿轮齿条机构15，前轮17；转角电机10及转矩电机13及双极减速器11、减速器14与齿轮齿条转向器15相连接，前轮17安装在齿轮齿条转向器15的两侧，前轮转角传感器9安装与前轮17上，转角传感器9与前轮力矩传感器12连接Flexray总线，将转角电机控制器8及转矩电机控制器16信号输入到总线中，再通过总线传输到容错控制器18中；转角电机10及其减速机构11连接转角控制单元8，转角电机控制单元8控制转角电机10及双极减速器11的运行，转矩电机13及减速器14连接转矩电机控制器16，转矩电机控制器16控制转矩电机13及减速器14的运行；容错控制器18的输出端分别与路感电机控制器6的输入端和Flexray总线相连接；容错控制器18接收传入到Flexary的前轮力矩电机传感器12，前轮转角电机传感器9，转向盘力矩传感器5的信号及运算控制器7的信号，行鲁棒性控制及补偿策略的控制，并把指令输入Flexery总线，并将指令传送给转角电机控制器8及转矩电机控制器16使相应电机动作。
其次，本发明还提供了一种基于上述线控转向双电机的主动容错和故障缓解***的模式切换控制方法，该方法包括如下步骤：
步骤1：汽车在行驶途中，采集单元将转角电机R 2和转矩电机的电阻R 3，电流信号I 2和I 3传递给电机故障诊断单元，电机故障诊断单元根据电阻与电流的大小，判定电机状态，并且输出电机电流与转矩的关系T＝f(I)，并将指令传递给容错控制策略单元；
步骤2：容错控制策略单元接收到来自故障诊断单元的诊断结果，得到转角电机或者转矩电机运行状态工况，并且通过比较转角电机电压U 2和转距电机电压U 3与参考阈值U 0比较，决定采取主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2；
步骤3：横摆角速度计算单元根据采集单元实时采集的方向盘转角信号δ sw，车速信号u根据变传动比规律计算出实时的理想的横摆角速度信号ω r *，再根据理想的横摆角速度信号ω r *与实际的横摆角速度信号ω r计算出所需调整的理想横摆角速度差值Δω r，并把横摆角速度差值Δω r传递给稳定性控制单元；
横摆角速度计算单元根据汽车实时车速u和前轮转角输入整车转向二自由度模型得到实际横摆角速度ω r。
Figure PCTCN2019116041-appb-000001
Δω r＝ω r-ω r *         (2)
式(1)中：m为汽车质量；Iz为汽车绕z轴的转动惯量；k 1、k 2分别为前后车轮的侧偏刚度；δ f为前轮转角；a，b分别为前、后轴至车辆质心的距离；u为车辆前进速度；ω r为横摆角速度；β为质心侧偏角；
步骤4：稳定性控制单元接收来自横摆角速度控制单元输入的横摆角速度差值Δω r，转换成相应的补偿转矩T 1,综合路面干扰形成的补偿转矩T 2，***摩擦形成的补偿转矩T 3,考虑***稳定性控制因素，采用μ综合鲁棒控制器控制，提高***抵抗外界干扰的能力，并且把补偿转矩ΔT传递给双机补偿单元；
ΔT＝ΔT 1+ΔT 2+ΔT 3     (3)
ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩；
步骤5：容错控制器接收来自稳定性控制单元的补偿转矩T，通过接受到容错控制器传来的的容错策略，选取对应的补偿策略，作用于双机执行单元和转向盘总成，保证汽车能有好的横摆角速度控制效果，及较好的稳定性。
进一步的，在上述一种基于上述线控转向双电机的主动容错和故障缓解***的模式切换控制方法中，还包括在步骤1中构建电机故障诊断单元，可以通过设计一个自适应的Kalman滤波器实现转角电机和转矩电机电阻，电流，电压的在线辨识：
其中：对于离散线性***：
x(k)＝Ax(k-1)+B(u(k)+w(k))     (4)
y v(k)＝Cx(k)+v(k)       (5)
式(4)、(5)中，x(k)时k时刻的***状态，x(k-1)时k-1时刻的***状态，A，B是***参数，u(k)是k时刻对***的控制量，w(k)为过程噪声信号，v(k)为测量噪声信号，y v(k)是***k时刻的测量值，C是矩阵；
离散卡尔曼滤波递推算法为：
Mn(k)＝P(k)C T/[CP(k)C T+R]     (6)
P(k)＝AP(k-1)A T+BQB T      (7)
P(k)＝(En-Mn(k)C)P(k)      (8)
x(k)＝Ax(k-1)+Mn(k)(y v(k)-CAx(k-1))       (9)
y e(k)＝Cx(k)        (10)
式(6)-(10)中x(k)时k时刻的***状态，x(k-1)时k-1时刻的***状态，A，B，R 是***参数，C是矩阵，A T是A矩阵的转置矩阵，B T是B矩阵的转置矩阵，C T是C矩阵的转置矩阵，y e(k)是经过卡尔曼滤波器修正后的输出信号，P(k)是***k时刻的协方差，P(k-1)是***k-1时刻的协方差,En是单位向量,Mn(k)是中间变量
En为单位向量，则***误差的协方差errcov(k)为：
errcov(k)＝CP(k)C T        (11)
式(11)中，errcov(k)是***误差的协方差，C是矩阵,C T是C矩阵的转置矩阵,P(k)是***k时刻的协方差。
根据基尔霍夫电压定律，构建转角电机与转矩电机的回路模型：
转角电机电学方程为：
Figure PCTCN2019116041-appb-000002
式(12)中：L为转向电机电感；R 2为转向电机电阻；k b2为电动势常数；u 2是转角电机的输入电压，
Figure PCTCN2019116041-appb-000003
是转角电机的电流，
Figure PCTCN2019116041-appb-000004
是转角电机转角加速度，k b2是转角电机的刚度。
转矩电机电学方程为：
Figure PCTCN2019116041-appb-000005
式中：L为转矩电机电感；R 3为转矩电机电阻；k b3为电动势常数；u 3是转矩电机的输入电压，i a3是转矩电机的电流，
Figure PCTCN2019116041-appb-000006
是转矩电机转角加速度，k b3是转角电机的刚度。
自适应的Kalman滤波器将转角电机，转矩电机的电压，电流，电阻信号传递给容错控制策略单元。
进一步的，所述步骤2中形成的四种实时容错控制策略，主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2的流程包括：
步骤2.1：Kalman滤波器通过监测电阻波动超出正常范围，可以判定转角电机或转矩电机故障。从电机性能最优化考虑，当电机的输出最大电压大于安全裕度电压即U>＝0.5U max,U 0＝0.5U max时，即可以认为电机可发挥电机部分功能，输出一定的转矩，转矩T＝f(I)，这是故障缓解策略的前提，较高的输出电压能力也是电机可以进行补偿工作的保证；
从安全性考虑，为了防止转角电机或者转矩电机不能够及时输出足够的转矩，当电机的最大电压小于安全裕度即U<＝0.5U max,U 0＝0.5U max时,即可认为故障电机不可发挥功能，故障电机不能完成补偿工作，此时***隔离故障电机，并进行主动容错策略的控制；
步骤2.2：定义0表示转角电机正常运行，1表示转角电机半正常运行，2代表转角电机不能运行，全故障，定义3表示转矩电机正常运行，4表示转矩电机半正常运行，5表示转矩电机不能运行，全故障；半正常运行表示U 2>＝U 0或者U 3>＝U 0；按照转角电机与转矩电机故障情 况形成故障向量表，该故障向量表包括转角电机与转矩电机的运行状态和对应的故障情况；所述故障向量表如下：
故障向量表
故障向量 故障情况
03 两个电机正常
25 两个电机全故障
04 转角电机正常，转矩电机半正常
13 转角电机半正常，转矩电机正常
05 转角电机正常，转矩电机全故障
23 转角电机全故障，转矩电机正常
15 转角电机半正常，转矩电机全故障
24 转角电机全故障，转矩电机半正常
14 转角电机半正常，转矩半正常
步骤2采取的容错策略具体包括：
1)当转角电机与转矩电机全部正常工作时，两个电机共同作用，控制前轮转角，以及汽车横摆角速度，此时无需容错策略；两个电机正常工作下，齿条运动分析如下：
齿条的运动微分方程为：
Figure PCTCN2019116041-appb-000007
式中：m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
Figure PCTCN2019116041-appb-000008
为齿条加速度，
Figure PCTCN2019116041-appb-000009
为齿条的运动速度；
车轮的运动微分方程为：
Figure PCTCN2019116041-appb-000010
式(15)中：J w为前轮的转动惯量；T frkp为摩擦力矩；B kp主销的阻尼系数。
Figure PCTCN2019116041-appb-000011
转向前轮的转角加速度，
Figure PCTCN2019116041-appb-000012
为转向前轮角速度，M Z为车轮的回正力矩；
2)当转角电机正常，转矩电机半正常，***进行故障缓解策略1，转角电机主要进行汽车横摆角速度控制，而转矩电机补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 1；
对综合ΔT 1＝ΔT 11+ΔT 21+ΔT 31      (16)
其中ΔT 1使总的补偿转矩，T 11使弥补横摆角速度差值所需的补偿转矩，T 21路面干扰形成的补偿转矩,T 31***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000013
式(17)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
3)当转角电机半正常，转矩电机正常，采用故障缓解策略2，转矩电机充当转角电机功能进行主要控制，转角电机充当转矩电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 2；
对综合ΔT 2＝ΔT 12+ΔT 22+ΔT 32      (18)
其中ΔT 2使总的补偿转矩，T 12使弥补横摆角速度差值所需的补偿转矩，T 22路面干扰形成的补偿转矩,T 32***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000014
4)当转角电机正常，转矩电机全故障，采用主动容错策略1，切断转矩电机电流输入，转角电机单独控制，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 3；
对其综合ΔT 3＝ΔT 13+ΔT 23+ΔT 33      (20)
其中ΔT 3使总的补偿转矩，T 13使弥补横摆角速度差值所需的补偿转矩，T 23路面干扰形成的补偿转矩,T 33***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000015
式(21)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
5)当转角电机全故障，转矩电机正常，采用主动容错策略2，切断转角电机电流输入，转矩电机单独控制，转矩电机充当转角电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 4；
对其综合ΔT 4＝ΔT 14+ΔT 24+ΔT 34      (22)
其中ΔT 4使总的补偿转矩，T 14使弥补横摆角速度差值所需的补偿转矩，T 24路面干扰形成的补偿转矩,T 34***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000016
6)当两个电机正常的时候，不需要应用容错策略，当两个电机都有故障(半正常，或者全故障)，几率很小，不在本申请讨论范围之内。
进一步，上述基于线控转向双电机的主动容错和故障缓解***的模式切换控制方法中，所述步骤4中，μ综合鲁棒控制器的控制框架包括：
a)横摆角速度跟踪,||Z 1|| 2＝||W 1(ω r *-ω r)|| 2    (24)
其中，W 1为加权函数，通常设置成低通滤波器W 1＝k 1(as+b)/(cs+d)   (25)
式(24)(25)中||Z 1|| 2式被控对象的评价输出的2范数，ω r *是理想横摆角速度值，ω r是实际汽车横摆角速度值，W 1为加权函数，a,s,b,a,d是低通滤波器的参数。
μ综合鲁棒控制器要能够快速的跟踪不同容错策略下的理想横摆角速度与实际横摆角速度差值，又要对外界干扰如地面干扰，侧向风干扰有一个较好的干扰抑制，或者输出相应的补偿扭矩并且把补偿转矩ΔT传递给双机补偿单元；
b)补偿反馈，稳定性控制：ΔT＝ΔT 1+ΔT 2+ΔT 3       (26)
其中ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩。
本发明中，故障缓解的容错理念是相对于传统容错理念提出的。传统的研究思路是采用硬件冗余或者软件冗余的方式，硬件冗余考虑的是用新的硬件替代发生故障的硬件，将发生错误的硬件从***中分离出来，或者采用软件冗余的方式，用软件冗余代替硬件冗余，通过其他传感器或者执行器的计算数据通过推导，代替发生故障的部件的数据。而在实际过程中这是较为保守的容错方式，本质上就是替代关系，用新的部件代替故障的部件，用其他数据替代错误的数据，而此时的汽车可以称作“无病工作”。然而故障部件的剩余功能没有得到充分开发而浪费，而比如电机发生故障后并没有完全瘫痪，是可以使用一部分功能输出一定的扭矩，针对电机不同故障工况，可以采取故障电机与正常的电机同时工作，此时的汽车可以称作“带病工作”。本申请通过故障电机与正常电机的匹配与比较实现汽车实时最优控制。并且同时可以保证汽车在极端野外环境下较好的工作能力与性能，也为汽车到最进的维修点修理提供了保证。
与现有即使相比，通过本发明的线控转向双电机***及其容错模式切换控制方法，在汽 车线控转向***中实现了多种转向模式功能，依据汽车转向执行双电机不同的故障进行转向模式的切换，实现汽车实时的最优控制，是线控转向汽车经济性与灵活性的统一，并且充分利用故障部件的剩余功能，节省资源，具有广阔的市场应用前景。
附图说明
图1为本发明线控转向双电机***的结构布置简图。
图2为本发明线控转向双电机主动容错与故障缓解容错***控制装置原理图。
图3为本发明线控转向双电机主动容错与故障缓解容错***控制策略总图。
图4为基于横摆角速度反馈的带有容错功能的线控转向双电机汽车车辆稳定性控制***框图。
图中，1、转向盘；2、转向柱；3、路感电机；4、转向盘转角传感器；5、转向盘力矩传感器；6、路感电机控制器；7、运算控制器；8、转角电机控制器；9、前轮转角传感器；10、转角电机；11、双极减速器；12、前轮力矩传感器；13、转矩电机；14、减速器；15、齿轮齿条机构；16、转矩电机控制器；17、前轮；18、容错控制器；19、车速传感器。
具体实施方式
为了便于本领域技术人员的理解，下面结合实例与附图对本发明作进一步的说明，实施方式提及的内容并非对本发明的限定。
参照图1所示本发明的一种基于线控转向双电机的主动容错和故障缓解***在车体上的布置图，包括：采集单元、转向盘总成、ECU控制模块(型号MT20U2，在具体实施中，也可以使用M7或MT20U)、双机执行单元；
其中，采集单元与ECU控制模块、转向盘总成、双机执行单元分别连接；采集单元包括转向盘转角传感器4，转向盘力矩传感器5，前轮转角传感器9，前轮力矩传感器12，车速传感器19，横摆角速度传感器等采集汽车状态的传感器；采集单元实时将汽车行驶过程中车速信号、转向盘转角信号、转速传感器获得转向电机的转角信号、转矩传感器获得转矩电机的转矩信号以及横摆角速度传感器获得的汽车横摆角速度信号、转向前轮的转角信号等传给电子控制单元及横摆角速度计算单元；将转角电机与转矩电机的电阻、电压、电流信号发送给电机故障诊断单元；将故障诊断单元发送的指令传递给容错控制策略单元；将横摆角速度计算单元得出的理想横摆角速度与实际横摆角速度差值信号及路面干扰侧向风干扰等信号发送给双机容错补偿控制单元；
ECU控制模块与采集单元、双机执行单元、转向盘总成分别连接，主要包括运算控制器7和容错控制器18，运算控制器7包括电机故障诊断单元、电子控制单元；容错控制器18即 容错控制器，包括容错控制策略单元，横摆角速度计算单元，稳定性控制单元，双电机容错补偿单元；
ECU控制模块接收来自采集单元的信号，经过计算后把相应的指令传输给双机执行单元进行动作；具体而言，电机故障诊断单元为自适应的Kalman滤波器，以实现转角电机和转矩电机电阻，电流，电压的在线辨识，其根据采集单元传送的转角电机与转矩电机实时的电阻、电流、电压信号，判定电机的状态，并将电机的实际电压，电流信号传递给容错控制器。
容错控制器根据电机故障诊断单元传来的信号，对于不同的电机故障，通过主动容错及故障缓解的方式进行相应的容错补偿控制策略；横摆角速度计算单元根据采集单元传送的方向盘转角信号、车速信号计算出理想的横摆角速度信号，再根据理想的横摆角速度信号与实际的横摆角速度信号计算出所需调整的理想横摆角速度差值，并把横摆角速度差值传递给稳定性控制单元；稳定性控制单元根据横摆角速度计算单元传递的横摆角速度差值综合考虑路面干扰，侧向风，***摩擦等对汽车稳定的影响，从***鲁棒性出发，以保证汽车的稳定性为前提，得出补偿转矩并传递给双机容错补偿单元；双机容错补偿单元接收稳定性控制单元传递的补偿转矩信号,并且根据容错控制策略单元的容错策略，通过转矩电机控制器16控制转矩电机13动作，对***进行补偿，从而实现故障的主动容错或故障缓解。
转向盘总成与采集单元、ECU控制模块分别连接，所述转向盘总成包括转向盘1、转向柱2、路感电机3,路感电机控制器6,转向盘1通过转向杆柱2与路感电机3及其转向盘转角传感器4相连接，转向盘力矩传感器5安装在转向杆柱2上；路感电机控制器6连接路感电机3及转向盘力矩传感器5，控制路感电机3的运行。
双机执行单元与采集单元、ECU控制模块分别连接，所述双机执行单元包括依次连接的转角电机控制器8，转角电机10，双极减速器11，转矩电机控制器16，转矩电机13，减速器14，齿轮齿条机构15，前轮17；转角电机10及转矩电机13及双极减速器11、减速器14与齿轮齿条转向器15相连接，前轮17安装在齿轮齿条转向器15的两侧，前轮转角传感器9安装与前轮17上，转角传感器9与前轮力矩传感器12连接Flexray总线，将转角电机控制器8及转矩电机控制器16信号输入到总线中，再通过总线传输到容错控制器18中；转角电机10及其减速机构11连接转角控制单元8，转角电机控制单元8控制转角电机10及双极减速器11的运行，转矩电机13及减速器14连接转矩电机控制器16，转矩电机控制器16控制转矩电机13及减速器14的运行；容错控制器18的输出端分别与路感电机控制器6的输入端和Flexray总线相连接；容错控制器18接收传入到Flexary的前轮力矩电机传感器12，前轮转角电机传感器9，转向盘力矩传感器5的信号及运算控制器7的信号，行鲁棒性控制及 补偿策略的控制，并把指令输入Flexery总线，并将指令传送给转角电机控制器8及转矩电机控制器16使相应电机动作。
图2、3为线控转向双电机主动容错与故障缓解容错***控制装置原理图和线控转向双电机主动容错与故障缓解容错***控制策略总图，本发明的控制流程如下：
步骤1：汽车在行驶途中，采集单元将转角电机R 2和转矩电机的电阻R 3，电流信号I 2和I 3传递给电机故障诊断单元，电机故障诊断单元根据电阻与电流的大小，判定电机状态，并且输出电机电流与转矩的关系T＝f(I)，并将指令(转矩电机的电压，电流，电阻信号)传递给容错控制策略单元；
所述电机故障诊断单元包括自适应的Kalman滤波器实现转角电机和转矩电机电阻，电流，电压的在线辨识：
其中：对于离散线性***：
x(k)＝Ax(k-1)+B(u(k)+w(k))      (4)
y v(k)＝Cx(k)+v(k)       (5)
式(4)、(5)中，x(k)时k时刻的***状态，x(k-1)时k-1时刻的***状态，A，B是***参数，u(k)是k时刻对***的控制量，w(k)为过程噪声信号，v(k)为测量噪声信号，y v(k)是***k时刻的测量值，C是矩阵；
离散卡尔曼滤波递推算法为：
Mn(k)＝P(k)C T/[CP(k)C T+R]     (6)
P(k)＝AP(k-1)A T+BQB T       (7)
P(k)＝(En-Mn(k)C)P(k)       (8)
x(k)＝Ax(k-1)+Mn(k)(y v(k)-CAx(k-1))       (9)
y e(k)＝Cx(k)        (10)
式(6)-(10)中x(k)时k时刻的***状态，x(k-1)时k-1时刻的***状态，A，B，R是***参数，C是矩阵，A T是A矩阵的转置矩阵，B T是B矩阵的转置矩阵，C T是C矩阵的转置矩阵，y e(k)是经过卡尔曼滤波器修正后的输出信号，P(k)是***k时刻的协方差，P(k-1)是***k-1时刻的协方差,En是单位向量,Mn(k)是中间变量
En为单位向量，则***误差的协方差errcov(k)为：
errcov(k)＝CP(k)C T      (11)
式(11)中，errcov(k)是***误差的协方差，C是矩阵,C T是C矩阵的转置矩阵,P(k)是***k时刻的协方差。
根据基尔霍夫电压定律，构建转角电机与转矩电机的回路模型：
转角电机电学方程为：
Figure PCTCN2019116041-appb-000017
式(12)中：L为转向电机电感；R 2为转向电机电阻；k b2为电动势常数；u 2是转角电机的输入电压，
Figure PCTCN2019116041-appb-000018
是转角电机的电流，
Figure PCTCN2019116041-appb-000019
是转角电机转角加速度，k b2是转角电机的刚度。
转矩电机电学方程为：
Figure PCTCN2019116041-appb-000020
式中：L为转矩电机电感；R 3为转矩电机电阻；k b3为电动势常数；u 3是转矩电机的输入电压，
Figure PCTCN2019116041-appb-000021
是转矩电机的电流，
Figure PCTCN2019116041-appb-000022
是转矩电机转角加速度，k b3是转角电机的刚度；
步骤2：容错控制策略单元接收到来自故障诊断单元的诊断结果，得到转角电机或者转矩电机运行状态工况，并且通过比较转角电机电压U 2和转距电机电压U 3与参考阈值U 0比较，决定采取主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2；
上述主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2的流程包括：
步骤2.1：Kalman滤波器通过监测电阻波动超出正常范围，可以判定转角电机或转矩电机故障。从电机性能最优化考虑，当电机的输出最大电压大于安全裕度电压即U>＝0.5U max,U 0＝0.5U max时，即可以认为电机可发挥电机部分功能，输出一定的转矩，转矩T＝f(I)，这是故障缓解策略的前提，较高的输出电压能力也是电机可以进行补偿工作的保证；
从安全性考虑，为了防止转角电机或者转矩电机不能够及时输出足够的转矩，当电机的最大电压小于安全裕度即U<＝0.5U max,U 0＝0.5U max时,即可认为故障电机不可发挥功能，故障电机不能完成补偿工作，此时***隔离故障电机，并进行主动容错策略的控制；
步骤2.2：定义0表示转角电机正常运行，1表示转角电机半正常运行，2代表转角电机不能运行，全故障，定义3表示转矩电机正常运行，4表示转矩电机半正常运行，5表示转矩电机不能运行，全故障；半正常运行表示U 2>＝U 0或者U 3>＝U 0；按照转角电机与转矩电机故障情况形成故障向量表，该故障向量表包括转角电机与转矩电机的运行状态和对应的故障情况；所述故障向量表如下：
故障向量表
故障向量 故障情况
03 两个电机正常
25 两个电机全故障
04 转角电机正常，转矩电机半正常
13 转角电机半正常，转矩电机正常
05 转角电机正常，转矩电机全故障
23 转角电机全故障，转矩电机正常
15 转角电机半正常，转矩电机全故障
24 转角电机全故障，转矩电机半正常
14 转角电机半正常，转矩半正常
步骤2采取的容错策略具体包括：
1)当转角电机与转矩电机全部正常工作时，两个电机共同作用，控制前轮转角，以及汽车横摆角速度，此时无需容错策略；两个电机正常工作下，齿条运动分析如下：
齿条的运动微分方程为：
Figure PCTCN2019116041-appb-000023
式中：m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
Figure PCTCN2019116041-appb-000024
为齿条加速度，
Figure PCTCN2019116041-appb-000025
为齿条的运动速度；
车轮的运动微分方程为：
Figure PCTCN2019116041-appb-000026
式(15)中：J w为前轮的转动惯量；T frkp为摩擦力矩；B kp主销的阻尼系数。
Figure PCTCN2019116041-appb-000027
转向前轮的转角加速度，
Figure PCTCN2019116041-appb-000028
为转向前轮角速度，M Z为车轮的回正力矩；
2)当转角电机正常，转矩电机半正常，***进行故障缓解策略1，转角电机主要进行汽车横摆角速度控制，而转矩电机补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 1；
对综合ΔT 1＝ΔT 11+ΔT 21+ΔT 31       (16)
其中ΔT 1使总的补偿转矩，T 11使弥补横摆角速度差值所需的补偿转矩，T 21路面干扰形成的补偿转矩,T 31***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000029
式(17)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉 杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
3)当转角电机半正常，转矩电机正常，采用故障缓解策略2，转矩电机充当转角电机功能进行主要控制，转角电机充当转矩电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 2；
对综合ΔT 2＝ΔT 12+ΔT 22+ΔT 32       (18)
其中ΔT 2使总的补偿转矩，T 12使弥补横摆角速度差值所需的补偿转矩，T 22路面干扰形成的补偿转矩,T 32***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000030
4)当转角电机正常，转矩电机全故障，采用主动容错策略1，切断转矩电机电流输入，转角电机单独控制，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 3；
对其综合ΔT 3＝ΔT 13+ΔT 23+ΔT 33      (20)
其中ΔT 3使总的补偿转矩，T 13使弥补横摆角速度差值所需的补偿转矩，T 23路面干扰形成的补偿转矩,T 33***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000031
式(21)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
5)当转角电机全故障，转矩电机正常，采用主动容错策略2，切断转角电机电流输入，转矩电机单独控制，转矩电机充当转角电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 4；
对其综合ΔT 4＝ΔT 14+ΔT 24+ΔT 34        (22)
其中ΔT 4使总的补偿转矩，T 14使弥补横摆角速度差值所需的补偿转矩，T 24路面干扰形成的补偿转矩,T 34***摩擦形成的补偿转矩；
Figure PCTCN2019116041-appb-000032
6)当两个电机正常的时候，不需要应用容错策略，当两个电机都有故障(半正常，或者全故障)，几率很小，不在本申请讨论范围之内。
进一步，上述基于线控转向双电机的主动容错和故障缓解***的模式切换控制方法中，所述步骤4中，μ综合鲁棒控制器的控制框架图如图4所示，图4中，K为控制器，***的扰动输入ω r *为理想的横摆角速度，干扰输入为理想的前轮转角δ f *，侧向风干扰F v以及路面的干扰力矩T r，W 1，W 2为加权函数，通常设置成高通滤波器。W d为干扰加权矩阵，ΔG为未知参数摄动，ΔI是补偿电流，z 1，z 2为评价输出。
具体而言，μ综合鲁棒控制器的控制框架包括：
a)横摆角速度跟踪,||Z 1|| 2＝||W 1(ω r *-ω r)|| 2        (24)
其中，W 1为加权函数，通常设置成低通滤波器W 1＝k 1(as+b)/(cs+d)    (25)
式(24)(25)中||Z 1|| 2式被控对象的评价输出的2范数，ω r *是理想横摆角速度值，ω r是实际汽车横摆角速度值，W 1为加权函数，a,s,b,a,d是低通滤波器的参数。
μ综合鲁棒控制器要能够快速的跟踪不同容错策略下的理想横摆角速度与实际横摆角速度差值，又要对外界干扰如地面干扰，侧向风干扰有一个较好的干扰抑制，或者输出相应的补偿扭矩并且把补偿转矩ΔT传递给双机补偿单元；
b)补偿反馈，稳定性控制：ΔT＝ΔT 1+ΔT 2+ΔT 3    (26)
其中ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩；
步骤3：横摆角速度计算单元根据采集单元实时采集的方向盘转角信号δ sw，车速信号u根据变传动比规律计算出实时的理想的横摆角速度信号ω r *，再根据理想的横摆角速度信号ω r *与实际的横摆角速度信号ω r计算出所需调整的理想横摆角速度差值Δω r，并把横摆角速度差值Δω r传递给稳定性控制单元；
横摆角速度计算单元根据汽车实时车速u和前轮转角输入整车转向二自由度模型得到实际横摆角速度ω r。
Figure PCTCN2019116041-appb-000033
Δω r＝ω r-ω r *      (2)
式(1)中：m为汽车质量；Iz为汽车绕z轴的转动惯量；k 1、k 2分别为前后车轮的侧偏刚度；δ f为前轮转角；a，b分别为前、后轴至车辆质心的距离；u为车辆前进速度；ω r为横摆角速度；β为质心侧偏角；
步骤4：稳定性控制单元接收来自横摆角速度控制单元输入的横摆角速度差值Δω r，转换成相应的补偿转矩T 1,综合路面干扰形成的补偿转矩T 2，***摩擦形成的补偿转矩T 3,考虑***稳定性控制因素，采用μ综合鲁棒控制器控制，提高***抵抗外界干扰的能力，并且把补偿转矩ΔT传递给双机补偿单元；
ΔT＝ΔT 1+ΔT 2+ΔT 3       (3)
ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩；
步骤5：容错控制器接收来自稳定性控制单元的补偿转矩T，通过接受到容错控制器传来的的容错策略，选取对应的补偿策略，作用于齿条机构，保证汽车能有好的横摆角速度控制效果，及较好的稳定性。
本发明具体应用途径很多，以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，再不脱离本发明原理的前提下，还可以做出若干改进，这些改进也应视为本发明的保护范围。

Claims (5)

  1. 一种基于线控转向双电机的主动容错和故障缓解***，其特征在于，所述***包括采集单元、转向盘总成、ECU控制模块、双机执行单元；
    其中，采集单元与ECU控制模块、转向盘总成及双机执行单元分别连接；所述采集单元包括转向盘转角传感器(4)，转向盘力矩传感器(5)，前轮转角传感器(9)，前轮力矩传感器(12)，车速传感器(19)，横摆角速度传感器；
    ECU控制模块与采集单元、双机执行单元、转向盘总成分别连接，所述ECU控制模块包括运算控制器(7)和容错控制器(18)，运算控制器(7)包括电机故障诊断单元、电子控制单元；容错控制器(18)包括容错控制策略单元，横摆角速度计算单元，稳定性控制单元，双电机容错补偿单元；
    转向盘总成包括转向盘(1)、转向柱(2)、路感电机(3),路感电机控制器(6),转向盘(1)通过转向杆柱(2)与路感电机(3)及转向盘转角传感器(4)相连接，转向盘力矩传感器(5)安装在转向杆柱(2)上，路感电机控制器(6)连接路感电机(3)及转向盘力矩传感器(5)，控制路感电机(3)的运行；
    双机执行单元包括转角电机控制器(8)，转角电机(10)，双极减速器(11)，转矩电机控制器(16)，转矩电机(13)，减速器(14)，齿轮齿条机构(15)，前轮(17)；
    齿轮齿条机构(15)与转角电机(10)、转矩电机(13)、双极减速器(11)、减速器(14)分别连接，前轮(17)安装在齿轮齿条机构(15)的两侧，前轮转角传感器(9)安装在前轮(17)上，前轮转角传感器(9)与前轮力矩传感器(12)连接总线，将转角电机控制器(8)及转矩电机控制器(16)的信号输入到总线中，再通过总线传输到容错控制器(18)中；转角电机(10)及双极减速器(11)分别连接转角电机控制器(8)；容错控制器(18)与路感电机控制器(6)及总线相连接；容错控制器(18)接收前轮力矩传感器(12)，前轮转角传感器(9)，转向盘力矩传感器(5)，运算控制器(7)传递的信号，并将指令传送给转角电机控制器(8)及转矩电机控制器(16)。
  2. 如权利要求1所述基于上述线控转向双电机的主动容错和故障缓解***的模式切换控制方法，其特在在于，具体步骤如下：
    步骤1：汽车在行驶途中，采集单元将转角电机R 2和转矩电机的电阻R 3，电流信号I 2和I 3传递给电机故障诊断单元，电机故障诊断单元根据电阻与电流的大小，判定电机状态，并且输出电机电流与转矩的关系T＝f(I)，并将指令传递给容错控制策略单元；
    步骤2：容错控制策略单元接收到来自故障诊断单元的诊断结果，得到转角电机或者转矩电机运行状态工况，并且通过比较转角电机电压U 2和转距电机电压U 3与参考阈值U 0比较， 决定采取主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2；
    步骤2.1：当电机的输出最大电压大于安全裕度电压，即U>＝0.5U max,U 0＝0.5U max时，即可以认为电机可发挥电机部分功能，输出一定的转矩，转矩T＝f(I)；当电机的最大电压小于安全裕度，即U<＝0.5U max,U 0＝0.5U max时,认为故障电机不可发挥功能，故障电机不能完成补偿工作，此时***隔离故障电机，并进行主动容错策略的控制；
    步骤2.2：定义0表示转角电机正常运行，1表示转角电机半正常运行，2代表转角电机不能运行，全故障，定义3表示转矩电机正常运行，4表示转矩电机半正常运行，5表示转矩电机不能运行，全故障；半正常运行表示U 2>＝U 0或者U 3>＝U 0；
    步骤3：横摆角速度计算单元根据采集单元实时采集的方向盘转角信号δ sw，车速信号u根据变传动比规律计算出实时的理想的横摆角速度信号ω r *，再根据理想横摆角速度信号ω r *与实际的横摆角速度信号ω r计算出所需调整的理想横摆角速度差值Δω r，并把横摆角速度差值Δω r传递给稳定性控制单元；
    横摆角速度计算单元根据汽车实时车速u和前轮转角输入整车转向二自由度模型得到实际横摆角速度ω r：
    Figure PCTCN2019116041-appb-100001
    Δω r＝ω r-ω r *    (2)
    式(1)中：m为汽车质量；Iz为汽车绕z轴的转动惯量；k 1、k 2分别为前后车轮的侧偏刚度；δ f为前轮转角；a，b分别为前、后轴至车辆质心的距离；u为车辆前进速度；ω r为横摆角速度；β为质心侧偏角；
    步骤4：稳定性控制单元接收来自横摆角速度控制单元输入的横摆角速度差值Δω r，转换成相应的补偿转矩T 1,综合路面干扰形成的补偿转矩T 2，***摩擦形成的补偿转矩T 3,考虑***稳定性控制因素，采用μ综合鲁棒控制器控制，并且把补偿转矩ΔT传递给双机补偿单元；
    ΔT＝ΔT 1+ΔT 2+ΔT 3    (3)
    ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩；
    步骤5：容错控制器接收来自稳定性控制单元的补偿转矩T，通过接受到容错控制器传来的的容错策略，选取对应的补偿策略，作用于双机执行单元。
  3. 根据权利要求2所述的方法，其特在在于，步骤1中，所述电机故障诊断单元，包括通过Kalman滤波器实现转角电机和转矩电机电阻，电流，电压的在线辨识：
    其中：对于离散线性***：
    x(k)＝Ax(k-1)+B(u(k)+w(k))    (4)
    y v(k)＝Cx(k)+v(k)    (5)
    式(4)、(5)中，x(k)为k时刻的***状态，x(k-1)为k-1时刻的***状态，A，B是***参数，u(k)是k时刻对***的控制量，w(k)为过程噪声信号，v(k)为测量噪声信号，y v(k)是***k时刻的测量值，C是矩阵；
    离散卡尔曼滤波递推算法为：
    Mn(k)＝P(k)C T/[CP(k)C T+R]   (6)
    P(k)＝AP(k-1)A T+BQB T    (7)
    P(k)＝(En-Mn(k)C)P(k)   (8)
    x(k)＝Ax(k-1)+Mn(k)(y v(k)-CAx(k-1))   (9)
    y e(k)＝Cx(k)    (10)
    式(6)-(10)中x(k)时k时刻的***状态，x(k-1)时k-1时刻的***状态，A，B，R是***参数，C是矩阵，A T是A矩阵的转置矩阵，B T是B矩阵的转置矩阵，C T是C矩阵的转置矩阵，y e(k)是经过卡尔曼滤波器修正后的输出信号，P(k)是***k时刻的协方差，P(k-1)是***k-1时刻的协方差,En是单位向量,Mn(k)是中间变量；
    En为单位向量，则***误差的协方差errcov(k)为：
    errcov(k)＝CP(k)C T   (11)
    式(11)中，errcov(k)是***误差的协方差，C是矩阵,C T是C矩阵的转置矩阵,P(k)是***k时刻的协方差；
    根据基尔霍夫电压定律，构建转角电机与转矩电机的回路模型：
    转角电机电学方程为：
    Figure PCTCN2019116041-appb-100002
    式(12)中：L为转向电机电感；R 2为转向电机电阻；k b2为电动势常数；u 2是转角电机的输入电压，
    Figure PCTCN2019116041-appb-100003
    是转角电机的电流，
    Figure PCTCN2019116041-appb-100004
    是转角电机转角加速度，k b2是转角电机的刚度。
    转矩电机电学方程为：
    Figure PCTCN2019116041-appb-100005
    式中：L为转矩电机电感；R 3为转矩电机电阻；k b3为电动势常数；u 3是转矩电机的输入 电压，i a3是转矩电机的电流，
    Figure PCTCN2019116041-appb-100006
    是转矩电机转角加速度，k b3是转角电机的刚度。
  4. 根据权利要求3所述的方法，其特征在于，步骤2中形所述主动容错策略1，或主动容错策略2，或故障缓解策略1，或故障缓解策略2的流程包括：
    1)当转角电机与转矩电机全部正常工作时，两个电机共同作用，控制前轮转角，以及汽车横摆角速度，此时无需容错策略；两个电机正常工作下，齿条运动分析如下：
    齿条的运动微分方程为：
    Figure PCTCN2019116041-appb-100007
    式中：m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
    Figure PCTCN2019116041-appb-100008
    为齿条加速度，
    Figure PCTCN2019116041-appb-100009
    为齿条的运动速度；
    车轮的运动微分方程为：
    Figure PCTCN2019116041-appb-100010
    式(15)中：J w为前轮的转动惯量；T frkp为摩擦力矩；B kp主销的阻尼系数。
    Figure PCTCN2019116041-appb-100011
    转向前轮的转角加速度，
    Figure PCTCN2019116041-appb-100012
    为转向前轮角速度，M Z为车轮的回正力矩；
    2)当转角电机正常，转矩电机半正常，***进行故障缓解策略1，转角电机主要进行汽车横摆角速度控制，而转矩电机补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 1；
    对综合ΔT 1＝ΔT 11+ΔT 21+ΔT 31    (16)
    其中ΔT 1使总的补偿转矩，T 11使弥补横摆角速度差值所需的补偿转矩，T 21路面干扰形成的补偿转矩,T 31***摩擦形成的补偿转矩；
    Figure PCTCN2019116041-appb-100013
    式(17)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
    3)当转角电机半正常，转矩电机正常，采用故障缓解策略2，转矩电机充当转角电机功能进行主要控制，转角电机充当转矩电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 2；
    对综合ΔT 2＝ΔT 12+ΔT 22+ΔT 32     (18)其中ΔT 2使总的补偿转矩，T 12使弥补横摆角速度差值所需的补偿转矩，T 22路面干扰形成的补偿转矩,T 32***摩擦形成的补偿转矩；
    Figure PCTCN2019116041-appb-100014
    4)当转角电机正常，转矩电机全故障，采用主动容错策略1，切断转矩电机电流输入，转角电机单独控制，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 3；
    对其综合ΔT 3＝ΔT 13+ΔT 23+ΔT 33    (20)其中ΔT 3使总的补偿转矩，T 13使弥补横摆角速度差值所需的补偿转矩，T 23路面干扰形成的补偿转矩,T 33***摩擦形成的补偿转矩；
    Figure PCTCN2019116041-appb-100015
    式(21)中，m rack为齿条的质量；y rack为齿条的位移；r L为主销轴的偏置；K L为转向拉杆刚度；B rack为齿条阻尼系数；F frrack为***间的摩擦力,G为双减速器机构的减速比；T g2是转向电机2的输出转矩；T g3是转向电机3的输出转矩；
    5)当转角电机全故障，转矩电机正常，采用主动容错策略2，切断转角电机电流输入，转矩电机单独控制，转矩电机充当转角电机功能，进行补偿横摆角速度控制器反馈回来的补偿扭矩ΔT 4；
    对其综合ΔT 4＝ΔT 14+ΔT 24+ΔT 34   (22)
    其中ΔT 4使总的补偿转矩，T 14使弥补横摆角速度差值所需的补偿转矩，T 24路面干扰形成的补偿转矩,T 34***摩擦形成的补偿转矩；
    Figure PCTCN2019116041-appb-100016
  5. 根据权利要求3所述的方法，其特征在于，步骤4中，所述μ综合鲁棒控制器的控制框架包括：
    a)横摆角速度跟踪,||Z 1|| 2＝||W 1(ω r *-ω r)|| 2  (24)
    其中，W 1为加权函数，通常设置成低通滤波器W 1＝k 1(as+b)/(cs+d)  (25)
    式(24)(25)中，||Z 1|| 2式被控对象的评价输出的2范数，ω r *是理想横摆角速度值，ω r是实际汽车横摆角速度值，W 1为加权函数，a,s,b,a,d是低通滤波器的参数；
    μ综合鲁棒控制器输出相应的补偿扭矩并且把补偿转矩ΔT传递给双机补偿单元；
    b)补偿反馈，稳定性控制：ΔT＝ΔT 1+ΔT 2+ΔT 3    (26)
    其中ΔT使总的补偿转矩，ΔT 1使弥补横摆角速度差值所需的补偿转矩，ΔT 2路面干扰形成的补偿转矩,ΔT 3***摩擦形成的补偿转矩。
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