A dual-redundancy drive-by-wire steering redundant fault-tolerant control system

Abstract

The application discloses a dual-redundancy redundant fault-tolerant control system for steer-by-wire, which comprises a dual-redundancy steering controller, a state monitoring controller, dual-redundancy road feeling motors, dual-redundancy steering motors, a control circuit and a dual-redundancy control network. The dual-redundancy steering controller and the state monitoring controller jointly form a controller group of the dual-redundancy steer-by-wire control system. The target steering angle of the dual-redundancy road feeling motors is received through the dual-redundancy control network, and the road feeling control current is fed back. The dual-redundancy steering controller sends the current control signal to the steering motor according to the steering angle signal of the road feeling motor, and the current feedback of the steering motor is used for the torque signal of the road feeling motor. The state monitoring controller is responsible for monitoring the working state of the dual-redundancy steering controller and simultaneously serves as a bridge connecting the steering controller and the road feeling motor to ensure the system redundancy fault tolerance, so that the working safety of the steer-by-wire system can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile technology, and belongs to automobile active safety and control. BACKGROUND

[0002] With the development of intelligent vehicle systems, steer-by-wire (SBW) technology has attracted more and more attention. Steer-by-wire technology gets rid of the dependence on complex mechanical structures, and shifts the focus of technology to the design of active steering control strategy. The steering motion of the vehicle is controlled by a motor-driven steering system, and the steering wheel resistance torque during steering is also simulated by the motor to get rid of the restriction of mechanical connection of the traditional steering system, realizing the function of variable steering transmission ratio. The steering column and other structures are cancelled to avoid the damage to the driver caused by the steering column in the collision accident.

[0003] For example, the publication number is CN110325429A, the publication date is October 11, 2019, and the patent name is "operation method for steer-by-wire steering system, control unit for steer-by-wire steering system, steer-by-wire steering system and vehicle". The publication discloses an operation method for a steer-by-wire steering system. The steer-by-wire steering system is configured with a steering transmission mechanism module, a steering wheel module, and a bus connecting the steering transmission mechanism module and the steering wheel module. In the operation method, the actual position in the steering transmission mechanism module is detected, and the theoretical position in the steering wheel module is controlled relative to the actual position in the steering transmission mechanism module using the associated rules.

[0004] However, similar steer-by-wire systems have certain safety hazards. When the steering system fails, the connection pipe column between the steering wheel and the steering mechanism is cancelled, which does not meet the "failure safety" state defined in ISO26262 functional safety standard. In addition, the ISO21448 safety standard proposes the "failure operational" feature for the steering system under high-level auxiliary and automatic driving scenarios. SUMMARY

[0005] The technical problem to be solved by the present application is to realize a dual-redundancy steer-by-wire redundant fault-tolerant control system that improves the working safety of the steer-by-wire system.

[0006] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a dual-redundancy LKAS steering redundancy fault-tolerant control system, a road feel motor is installed at the end of a steering wheel, the road feel motor outputs an induction signal to a steering controller, the steering controller outputs a steering signal to a steering motor to execute a steering action, the road feel motor is a dual-redundancy road feel motor, the dual-redundancy road feel motor has two sets of independent windings for sensing a steering wheel steering angle, both sets of the windings output induction signals to the steering controller.

[0007] Both sets of the windings output induction signals to a state controller, the state controller is used for judging whether two induction signals are normal, and the state controller outputs a dual-redundancy road feel motor working condition signal to the steering controller.

[0008] The output signal of the dual-redundancy road feel motor is one main and one auxiliary, and the main and auxiliary signals are compared with each other as a fault reference signal, when a set of windings fails, an alarm is given, and then the signal of the other set of windings is taken as an input signal of the steering controller, and an alarm is given in the vehicle.

[0009] The steering controller is a dual-redundancy steering controller, has two sets of independent control circuits and chips, the two sets of control circuits and chips complementarily intervene each other, and independently receive and process the input signal of one set of windings of the dual-redundancy road feel motor.

[0010] The dual-redundancy steering controller is connected to and outputs a driving signal to the steering motor, the dual-redundancy steering controller is used for controlling a torque, a speed and a position of the steering motor, and the steering motor is used for feeding back a current and acting on the road feel motor to form a steering wheel road feel feedback.

[0011] The steering motor is a dual-redundancy steering motor, has two independent motors outputting driving forces to a steering actuator of a vehicle, and two output paths of the dual-redundancy steering controller are respectively connected to the two independent motors of the dual-redundancy steering motor.

[0012] The dual-redundancy steering controller is provided with two independent CPUs, each of the CPUs is provided with an independent driver, both of the drivers are connected to and output driving signals to the two independent motors of the dual-redundancy steering motor, the two CPUs communicate with each other, and both of the CPUs communicate with a state monitor.

[0013] When the state monitor works normally, the data collected from the redundancy network is processed, the operation of multiple CPUs is monitored and coordinated, and then the operation of the driver is controlled to generate a sine wave to control the rotation of the dual-redundancy motor; when the state monitor works abnormally, the two CPUs communicate with each other to complete mutual monitoring, and the CPUs are used for monitoring the working state of the connected driver.

[0014] The CPU and the state monitor jointly send heartbeat messages to the redundancy network, and the working state of the target device is determined through the heartbeat messages; when one of the CPUs does not work normally, the sending of the heartbeat messages is stopped; the working state of the CPU is determined by the state monitor according to whether the heartbeat messages are received; the state monitor also sends heartbeat messages to the CPU while receiving the heartbeat messages from the CPU; and the working state of the state monitor is determined by the CPU according to whether the heartbeat messages are received.

[0015] The system is provided with two sets of independent control networks, and the two sets of windings are in communication with the steering controller and the state controller through the independent control networks.

[0016] The motor of the system is composed of multiple windings without neutral point isolation; when one of the windings fails during operation, the model of the motor after the failure is reconfigured from a six-phase motor model to a five-phase motor model.

[0017] The double-redundancy steering controller and the state monitoring controller jointly constitute a controller group of the double-redundancy steer-by-wire steering machine control system, receive the target steering angle from the double-redundancy road feeling motor of the steering machine through the redundancy control network, and simultaneously feed back the road feeling control current; the double-redundancy steering controller sends the current control signal to the steering motor according to the steering angle signal of the road feeling motor, and the feedback current of the steering motor is used for the torque signal of the road feeling motor; the state monitoring controller is responsible for monitoring the working state of the double-redundancy steering controller and simultaneously serves as a bridge connecting the steering controller and the road feeling motor to ensure the redundancy fault tolerance of the system. BRIEF DESCRIPTION OF DRAWINGS

[0018] The content expressed by each of the drawings in the specification of the present application is briefly described as follows:

[0019] Figure 1 It is a principle block diagram of the double-redundancy steer-by-wire redundancy fault tolerance control system;

[0020] Figure 2 It is a principle block diagram of the controller redundancy fault tolerance of the double-redundancy steer-by-wire redundancy fault tolerance control system;

[0021] Figure 3 It is a principle block diagram of the motor redundancy fault tolerance of the double-redundancy steer-by-wire redundancy fault tolerance control system. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application are further described in detail below with reference to the drawings and by describing the embodiments, the shape, structure, mutual position and connection relationship between the parts, the action and working principle of each part, the manufacturing process and the operation and use method of each component involved in the specific embodiments of the present application are described in further detail, to help the technical personnel in the field to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present application.

[0023] The system comprises a double-redundancy steering controller, a state controller, a double-redundancy road feeling motor, a double-redundancy steering motor, a control circuit and a double-redundancy control network, the double-redundancy steering controller and the state controller jointly constitute a controller group of the double-redundancy steer-by-wire steering machine control system, the double-redundancy road feeling motor and the double-redundancy steering motor also have a redundant fault-tolerant function, when a set of windings fails, the motor can still continue to complete the corresponding work instruction. The system cancels the connecting rod structure of the traditional steering direction machine steering wheel and chassis steering execution mechanism, installs the double-redundancy road feeling motor at the end of the steering wheel, and installs the double-redundancy steering motor on the chassis steering execution mechanism instead of the steering column mechanism to control the vehicle steering.

[0024] The double-redundancy control network is used for mutual communication between the redundant steering controller and the state controller, and for sending a torque signal to the double-redundancy road feeling motor and receiving an angle signal.

[0025] The double-redundancy steering controller is composed of multiple independent control circuits and chip sets, the control circuits complementarily intervene each other, and are uniformly controlled by respective chips, when part of the circuits or chips have problems, the other circuits and chips can still ensure the normal operation of the double-redundancy steer-by-wire steering redundant fault-tolerant control system.

[0026] The state controller is the core of the double-redundancy steer-by-wire steering redundant fault-tolerant control system, is used for processing information from the double-redundancy steering controller, judging whether the controller normally works, performing fault-tolerant processing when part of the circuits have faults, ensuring the normal operation of the steering system, adjusting the work of the multiple circuits and chip sets of the double-redundancy steering controller to prevent interference and control the coordinated operation of the steering system, receiving information from the redundancy network for processing, obtaining a target torque of the road feeling motor through current feedback of the steering motor, and obtaining a target position, a target current and a target speed of the steering motor through target angle speed calculation of the road feeling motor feedback.

[0027] The redundancy network is responsible for mutual communication between various functional devices of the steer-by-wire steering system, through the redundancy network, each device receives the control information required by itself for next step control, and sends the feedback information required by itself to the redundancy network. The control circuit connects the power supply circuit of the double-redundancy steering controller, the double-redundancy road feeling motor of the direction machine and the double-redundancy steering motor. The double-redundancy steering controller is subjected to circuit redundancy and chip redundancy, the controller has multiple control circuits, master control chips and driving circuits, the circuits and chips work redundantly, when a circuit or a chip has a fault, the circuit stops working and is replaced by other circuits. Each control chip sends a heartbeat message to other control chips to inform the working state of itself, when a control chip has a fault or the circuit where the control chip is located has a fault, an error state is sent to other control chips to inform that the control chip and the circuit where the control chip is located cannot normally work.

[0028] The state controller monitors the normal operation of each function, receives heartbeat messages of each functional device through the redundancy network to determine whether each functional device is normally operating, and sends heartbeat messages of the state controller to let each functional device determine whether the state controller is normally working. When the state controller is normally working, each functional device works under the scheduling of the state controller, and each functional redundancy works. When the function cannot work, an error state is sent, the state controller acquires the error state, and schedules the work to other circuit fault tolerance. When the state controller stops working, an error state is sent, the controller receives the error state, stops the state controller for function scheduling, and the controller operates according to the priority order, the high-priority device works, and the low-priority device is in a dormant state. When the high-priority device sends a fault, an error state is sent to stop working, and the second high-priority device works.

[0029] As shown in Figure 1 , the dual-redundancy LIN steer redundant fault-tolerant control system includes a dual-redundancy road feel motor, a dual-redundancy steering controller, a state controller, and a dual-redundancy steering motor. The dual-redundancy road feel motor connects a steering wheel and receives a torque signal fed back to the driver through the redundancy network as a road feel torque. The angle value of the road feel motor is sent to the redundancy network, the state controller receives the position signal of the road feel motor, calculates the road feel motor current with the feedback value of the angle sensor, and sends the road feel motor current to the dual-redundancy controller to control the motor to work to a target position.

[0030] As shown in Figure 2 , the redundant fault-tolerant scheme of the dual-redundancy LIN steer redundant fault-tolerant control system is to design multiple sets of circuits with the same function in the dual-redundancy steering controller. When part of the circuits in all drivers fail, other circuits can be used to ensure the normal operation of the dual-redundancy LIN steer redundant fault-tolerant control system. Multiple CPUs and the state monitor communicate with each other to ensure the normal operation of the function. The CPU and the state controller can communicate individually or through the redundancy network. When the state monitor works normally, the data collected from the redundancy network is processed, the operation of multiple CPUs is monitored and coordinated, and the operation of the driver is controlled to generate a sine wave to control the rotation of the dual-redundancy motor. When the state monitor works abnormally, the CPU communicates with another CPU, and there is a CPU working priority at this time. When the high-priority CPU works normally, the high-priority CPU is used. When the high-priority CPU is abnormal, the second high-priority CPU is used. The failure diagnosis of the driver circuit is diagnosed by the CPU, and the driver circuit also has a priority selection sequence when the state monitor fails.

[0031] When the dual-redundancy steer-by-wire system is working, multiple CPUs and a state monitor jointly send heartbeat messages to a redundancy network to determine whether target devices are working normally. When CPU1 is not working normally, CPU1 stops sending heartbeat messages, the state monitor cannot receive the heartbeat messages from CPU1, determines that CPU1 is not working normally, and stops the work of CPU1, which is completed by other CPUs. The state monitor also sends heartbeat messages to the CPUs while receiving the heartbeat messages from the CPUs. The CPUs receive the heartbeat messages from the state monitor to determine that the state monitor is working normally, otherwise, a fault mode is determined. When the state monitor is determined to be not working normally, the CPUs receive the heartbeat messages from other CPUs in the redundancy network and work according to priorities.

[0032] As shown in Figure 3 The dual-redundancy motor of the dual-redundancy steer-by-wire redundant fault-tolerant control system is composed of multiple neutral-point non-isolated windings. When one of the windings fails, the model of the motor after the failure is reconfigured from a normal six-phase motor model to a five-phase motor model.

[0033] The above describes the present application with reference to the drawings, and it is obvious that the specific implementation of the present application is not limited to the above-described manner. Any non-essential improvement or direct application of the concept and technical solution of the present application to other occasions without improvement is within the protection scope of the present application.

Claims

1. A dual-redundancy redundant fault-tolerant control system for steer-by-wire, a road feel motor is mounted at the end of a steering wheel, the road feel motor outputs an induction signal to a steering controller, the steering controller outputs a steering signal to a steering motor to perform a steering action, characterized in that: The road feeling motor is a double-redundancy road feeling motor, which has two sets of independent windings for sensing the steering wheel steering angle, and both of the windings output sensing signals to a steering controller; Both of the windings output sensing signals to a state controller, which is used for judging whether the two sensing signals are normal, and outputs a double-redundancy road feeling motor working condition signal to the steering controller; The steering controller is a double-redundancy steering controller, which is connected to and outputs a driving signal to a steering motor, and is used for controlling the torque, speed and position of the steering motor, which is used for feeding back current and acting on the road feeling motor to form a steering wheel road feeling feedback. The steering motor is a double-redundancy steering motor, which has two independent motors outputting driving force to the steering actuator of the vehicle, and two outputs of the double-redundancy steering controller are connected to the two independent motors of the double-redundancy steering motor. The double-redundancy steering controller is provided with two independent CPUs, each of which is provided with an independent driver, both of which are connected to and output driving signals to the two independent motors of the double-redundancy steering motor, and the two CPUs communicate with each other and with a state monitor. When the state monitor works normally, the data collected from the redundancy network is processed, the operation of multiple CPUs is monitored and coordinated, and the operation of the driver is controlled to generate a sine wave to control the rotation of the double-redundancy motor; when the state monitor works abnormally, the two CPUs communicate with each other to monitor each other, and the CPU is used to monitor the working state of the connected driver. The CPU and the state monitor jointly send and receive heartbeat messages to the redundancy network, and determine whether the target device works normally through the heartbeat messages; when one of the CPUs does not work normally, the heartbeat messages are stopped, and the state monitor determines the working state of the CPU according to whether the heartbeat messages are received; the state monitor also sends heartbeat messages to the CPU while receiving the heartbeat messages from the CPU, and the CPU determines the working state of the state monitor according to whether the heartbeat messages are received. The system is provided with two independent control networks, and the two sets of windings are connected to the steering controller and the state controller through the independent control networks.

2. The dual-redundancy steer-by-wire redundant fault-tolerant control system of claim 1, wherein: The output signals of the double-redundancy road feeling motor are primary and secondary, and the primary and secondary signals are compared with each other as a fault reference signal; when one set of windings fails, an alarm is given, and the signal of the other set of windings is used as the input signal of the steering controller, and an alarm is given in the vehicle.

3. The dual-redundancy steer-by-wire redundant fault-tolerant control system of claim 2, wherein: The double-redundancy steering controller has two independent control circuits and chips, and the two control circuits and chips complementarily intervene with each other and independently receive and process the input signals of one set of windings of the double-redundancy road feeling motor.

4. The dual-redundancy steer-by-wire redundant fault-tolerant control system according to claim 1, 2 or 3, characterized in that: The motor of the system is composed of multiple neutral point non-isolated windings, and when one of the windings fails, the model of the motor after failure is reconstructed from a six-phase motor model to a five-phase motor model.

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