CN109733460B - Redundant electronic steering brake system - Google Patents
Redundant electronic steering brake system Download PDFInfo
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- CN109733460B CN109733460B CN201810150007.XA CN201810150007A CN109733460B CN 109733460 B CN109733460 B CN 109733460B CN 201810150007 A CN201810150007 A CN 201810150007A CN 109733460 B CN109733460 B CN 109733460B
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Abstract
The invention discloses a redundant electronic steering brake system, which comprises two electronic power steering units, a main brake unit and a slave brake unit; the two electronic power steering units are used for jointly controlling the steering of the vehicle; the main braking unit is used for receiving a control instruction from the automobile bus, resolving the control instruction and outputting an execution result; the slave brake unit is used for receiving a control command from the automobile bus, resolving the control command, and deciding whether to execute the output of the result or not based on the state signal of the master brake unit. The invention can meet the safety requirement of automatic driving.
Description
Technical Field
The invention belongs to the technical field of automatic driving of automobiles, and particularly relates to a redundant electronic steering brake system.
Background
With the development of modern technology and technology, people have higher requirements on vehicles, and on the basis of meeting the traditional driving, intelligent control of the vehicles, such as functions of unmanned automobiles, self-adaptive cruising, active safety of the vehicles, full-automatic parking and the like, are required. Among them, the electric power steering control system and the brake system are important parts in intelligent control, and reliability and safety are particularly important.
The existing electric power steering control system (EPS) is composed of a corner torque sensor, a vehicle speed sensor, a control unit processor, a power-assisted motor and the like. The basic working principle is as follows: the steering wheel torque signal and the vehicle speed signal measured by the steering angle torque sensor are transmitted to the control unit processor, and the steering angle signal and the vehicle speed signal are processed and calculated by the processor to determine the steering and the power-assisted current of the power-assisted motor, so that the steering power-assisted control is completed. However, the existing electric power steering control system is designed based on the steering improvement assistance of a driver, the functional safety level of the electric power steering control system can only reach KSIL-B, if each node is abnormal, the whole electric power steering control system will fail, serious consequences can be brought to safe driving, and the functional safety requirement of automatic driving cannot be met.
The existing braking system comprises a power CAN line, a central controller, a power supply, a braking unit and a wheel speed sensor, wherein the wheel speed sensor is connected with the braking unit, the power supply is respectively connected with the central controller and the braking unit to supply power to the central controller and the braking unit, the braking unit is connected with the central controller through the power CAN line, receives a control instruction sent by the central controller, and executes corresponding operation based on the control instruction. The existing braking system is simple in structure and does not have a system-level redundancy function, and in the automatic driving process, if the braking system fails, the automatic driving vehicle can lose the braking function and cause serious personal and property loss.
Therefore, there is a need to develop a redundant electric steering brake system.
Disclosure of Invention
The invention aims to improve a redundant electronic steering brake system so as to meet the safety requirement of automatic driving.
The redundant electronic steering brake system comprises two electronic power steering units, a main brake unit and a slave brake unit;
the two electronic power steering units are used for jointly controlling the steering of the vehicle; each electronic power steering unit comprises a processor, and a corner torque sensor and a motor which are respectively connected with the processor; the corner torque sensor is used for outputting an actual torque signal and an angle signal of the current steering wheel and sending the actual torque signal and the angle signal to a processor connected with the angle signal; the processor is used for acquiring a currently expected steering wheel angle signal from the automobile bus; the processor is also used for calculating a total torque value K which is required to be output currently of the whole system according to a currently expected steering wheel angle signal and an angle signal obtained from the angle torque sensor, and calculating torque values which are required to be output by the respective electronic power steering units according to a distribution mechanism; the processor also controls a motor correspondingly connected with the processor according to the torque value to control the vehicle to realize steering;
wherein, the allocation mechanism is as follows: when the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units work simultaneously, the corresponding motors are controlled to work according to the torque values required to be output respectively, the vehicles are controlled to realize steering together, and the torque values required to be output by the two electronic power-assisted steering units meet the following formula: a+b=k, and a is more than or equal to 0.3K and less than or equal to 0.7K, a is a torque value currently required to be output by one of the electronic power steering units, and b is a torque value currently required to be output by the other electronic power steering unit; when a processor in one of the electronic power steering units, or a corner torque sensor or a motor fails, the other normal electronic power steering unit takes over the system to independently control the vehicle to realize steering;
the main braking unit is used for receiving and resolving the control instruction and outputting an execution result; the slave braking unit is used for receiving and resolving the control instruction and deciding whether to execute the output of the result or not based on the state signal of the master braking unit; wherein: the master brake unit and the slave brake unit monitor each other whether the opposite side state signal indicates a fault; executing a result output by the main brake unit in response to the state signal of the main brake unit being normal, wherein the result output is not executed by the slave brake unit at this time; and executing result output by the slave brake unit when the state signal of the master brake unit indicates that a fault failure occurs.
When both electronic power steering units are normal, the a satisfies: a is more than or equal to 0.4K and less than or equal to 0.6K.
When both electronic power steering units are normal, the a satisfies: a=0.5k; namely, the two electronic power steering units respectively output 0.5K; when the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units do work uniformly, so that the problem of excessive loss of one side is avoided; when any node in one electronic power steering unit fails, the output of the other electronic power steering unit can be quickly lifted from 0.5K to a target value K, and compared with the lifting from 0 to the target value, the response speed is faster, so that the system can meet the safety requirement of automatic driving.
The automobile bus comprises:
the two electronic power steering units, the master braking unit and the slave braking unit are connected with the first automobile bus;
the two electronic power steering units, the master braking unit and the slave braking unit are connected with the second automobile bus; the automobile buses are designed in a redundancy mode, and when one automobile bus fails, the other automobile bus can also ensure the normal operation of the system.
Further comprises:
the central controller is respectively connected with the first automobile bus and the second automobile bus, and is used for calculating a currently expected steering wheel angle signal, sending a control instruction, monitoring state signals of the master braking unit and the slave braking unit and respectively sending the currently expected steering wheel angle signal and the control instruction to the first automobile bus and the second automobile bus.
Further comprises:
the safety controller is respectively connected with the first automobile bus and the second automobile bus;
the safety controller is used for calculating a current expected steering wheel angle signal, and when the central controller is monitored to be not invalid, the current expected steering wheel angle signal is not sent to the two processors, or an invalid label is added to the current expected steering wheel angle signal, and the current expected steering wheel angle signal with the invalid label is sent to the two processors; when the failure of the central controller is monitored, the safety controller directly sends the calculated current expected steering wheel angle signal to a first automobile bus and a second automobile bus;
the control command is sent to the first automobile bus and the second automobile bus respectively, and the control command is used for sending the control command and monitoring the state signals of the master braking unit and the slave braking unit; that is, redundancy of the controllers is realized, and when one of the controllers fails, the other controller can also ensure normal operation of the system.
The power supply unit is also included;
the power supply unit comprises a main power supply and a secondary power supply;
the main power supply is electrically connected with the central controller, the main braking unit and one of the electronic power steering units respectively;
the secondary power supply is electrically connected with the safety controller, the secondary braking unit and the other electronic power steering unit respectively; the redundancy of the power supplies is realized, and when one power supply fails due to faults, the other power supply can also supply power to the slave brake unit and one path of electronic power steering unit, and the normal operation of the system or the normal operation in a short time can also be ensured.
The processors of the two electronic power steering units are also connected through one or two first communication lines; the two processors are subjected to information interaction through a first communication line, and the information interaction method is mainly used for mutual check sum monitoring and the like between the two processors; preferably, two first communication lines are adopted, namely redundancy of the first communication lines is realized, and when one of the first communication lines fails, the other first communication line can also ensure normal operation of the system;
the main braking unit and the auxiliary braking unit are also connected through one or two second communication lines and are used for data interaction between the main braking unit and the auxiliary braking unit; the main braking unit and the auxiliary braking unit are used for carrying out information interaction through a second communication line; preferably, two second communication lines are adopted, namely redundancy of the second communication lines is realized, and when one second communication line fails, the other second communication line can also ensure normal operation of the system;
the peak torque of the motor of each electronic power steering unit is 50% -100% of the maximum torque value B required by the vehicle (namely, the torque required by the vehicle to turn the steering wheel to a limit turning angle when the vehicle is at rest and is fully loaded), and when the vehicle is in a non-stationary state, even if one motor fails, the other motor can meet the steering requirement of the vehicle.
The peak torque of the motor of each electronic power steering unit is 50% of the maximum torque value B required by the vehicle respectively; the advantages are that: (1) When the two electronic power steering units are normal, the added capacity of the two electronic power steering units is B, so that the requirements of vehicle design can be met; (2) Experiments prove that under the condition of single-point failure, even if the peak torque of the motor is set to be 0.5B, a single electronic power-assisted steering unit can meet the steering requirement, except the power assistance required by the tail end of a static or ultra-low speed working condition, the automatic driving state belongs to a safe state when the vehicle is at a static or ultra-low speed, so that the system safety can be ensured by designing the peak torque of each motor to be 0.5B; (3) The higher the peak torque value of the motor is, the higher the cost configuration is, and the peak torque of each motor is designed to be 0.5B, so that the safety and the reliability of the system can be ensured, and the lowest cost configuration is realized; (4) if the peak torque of the two motors is different, for example; one peak torque is 0.3B and one peak torque is 0.7B, and when two motors with larger torques (such as 0.3B) are required to be simultaneously made, the motor with the peak torque of 0.3B needs to run at full load; while outputting a torque of 0.3B for a motor with a peak torque of 0.7B is very easy, this situation can lead to a motor with a peak torque of 0.3B being more prone to failure; in addition, if the motor with the peak torque of 0.7B fails, the motor with the peak torque of 0.3B cannot output the torque of 0.6B, so that when one single point fails, the system cannot ensure that the automatic driving is switched to the basic power assisting function of the human driving.
Further, when a processor in one of the electronic power steering units, or the corner torque sensor or the motor fails, the other normal electronic power steering unit controls the corresponding motor to work according to the total torque value K which is required to be output currently by the whole system.
The invention has the beneficial effects that:
(1) When the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units jointly control the vehicle to realize steering, and the peak torque of each motor does not need to reach the maximum torque required by the vehicle, so that the performance requirement on the motor can be properly reduced, and the cost of the vehicle can be reduced on the premise of meeting the automatic driving safety. In addition, when any one of two processors, two corner torque sensors and two motors in the system fails, the other electronic power steering unit which is in normal operation can also independently control the vehicle to realize steering, so that the safety requirement of automatic driving can be met.
(2) When one set of braking units fails, the other set of braking units can take over the system to ensure the normal running of the vehicle, so that a driver has enough reaction time to take over the vehicle, and the stability and the reliability of the vehicle braking system are improved;
(3) When the master braking unit and the slave braking unit receive the control instruction, as the master braking unit and the slave braking unit are both used for resolving the control instruction and mutually monitoring whether the other side has faults (such as the health state of the other side and the calculation result of the other side), if the other side is found to have faults and failures (such as the error of the calculation result of the other side or the unhealthy state of the other side is monitored), the non-failed side can quickly respond and is connected with the pipe system (the switching time is about 100 ms); namely, the two braking units are switched by adopting an internal coordination mode without being coordinated by an external controller, so that the response speed is high and smooth.
Drawings
FIG. 1 is a schematic block diagram of the present invention;
FIG. 2 is a control flow chart of two electronic power steering units according to the present invention;
FIG. 3 is a control flow chart of two brake units according to the present invention;
FIG. 4 is a control flow chart of the central controller and the safety controller according to the present invention;
FIG. 5 is a control flow chart of the master power supply and the slave power supply according to the present invention;
FIG. 6 is a control flow diagram of a first automotive bus and a second automotive bus according to the present invention;
FIG. 7 is a schematic block diagram of an electronic power steering unit according to the present invention;
in the figure: 1. the electronic power steering system comprises electronic power steering units Y,2, first communication lines, 3, electronic power steering units X,4, a second automobile bus, 5, a slave brake unit, 6, a second communication line, 7, a master brake unit, 8, a safety controller, 9, a central controller, 10, a power supply unit, 10a, a master power supply, 10b, a slave power supply, 11, a first automobile bus, 12, a first wheel speed sensor, 13 and a second wheel speed sensor.
Detailed Description
The redundant electric steering brake system of the present invention is described in detail below with reference to the accompanying drawings.
Example 1
As shown in fig. 1 and 4, the redundant electric power steering brake system according to the present invention includes two electric power steering units (i.e., an electric power steering unit X3 and an electric power steering unit Y1), a master brake unit 7, a slave brake unit 5, and a central controller 9. The central controller 9 is used for calculating and deciding an automatic driving function on the vehicle.
Two electronic power steering units (i.e., EPS systems) are used to jointly control the steering of the vehicle; each electronic power steering unit (namely EPS) comprises a processor, and a corner torque sensor and a motor which are respectively connected with the processor. The steering wheel comprises a steering wheel body, a steering wheel torque sensor, a processor, a steering wheel, a motor and a motor, wherein the steering wheel torque sensor is used for outputting current steering wheel actual torque signals and angle signals, and sending the current steering wheel actual torque signals and angle signals to the processor connected with the current steering wheel actual torque signals and the angle signals. The processor is configured to obtain a currently desired steering wheel angle signal from the vehicle bus. The processor is also used for calculating the total torque value K which is required to be output currently of the whole system according to the currently expected steering wheel angle signal and the angle signal obtained from the angle torque sensor, and calculating the torque values which are required to be output by the electronic power steering units respectively according to the distribution mechanism. And the processor also controls the motor correspondingly connected with the processor according to the torque value to control the vehicle to realize steering.
As shown in fig. 2, the allocation mechanism is:
when the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units work simultaneously, the corresponding motors are controlled to work according to the torque values required to be output respectively, the vehicles are controlled to realize steering together, and the torque values required to be output by the two electronic power-assisted steering units meet the following formula: a+b=k, and a is more than or equal to 0.3K and less than or equal to 0.7K, a is a torque value currently required to be output by one of the electronic power steering units, and b is a torque value currently required to be output by the other electronic power steering unit.
When a processor in one of the electronic power steering units, or the steering angle torque sensor, or the motor fails, the other normal electronic power steering unit takes over the system to independently control the vehicle to realize steering.
The central controller 9 is used for calculating the current expected steering wheel angle signal and sending the signal to the bus.
The advantages of this allocation mechanism are:
(1) The mechanism that the central controller 9 and the EPS system are mutually isolated is characterized in that the central controller 9 only sends an overall steering angle target to the EPS system, the dual processors in the EPS system mutually negotiate, the torque task distribution based on the overall steering angle target does not need to consider the task division of the EPS system in the stage of the central controller 9, the isolation of the respective operation functions of the EPS system and the central controller 9 in the intelligent automobile field is realized, and the seamless connection of the other system can be realized when the central controller 9 or the EPS system needs to be respectively upgraded.
(2) Considering the driving safety of intelligent automobiles, the redundancy of important EPS must be realized, in the prior art, an electronic steering system is designed into a double redundancy system, namely two sets of electronic steering power assisting units, and under normal conditions, only one set of electronic steering power assisting unit is in a working state, and the other set of redundant electronic steering power assisting unit is called only after the default electronic steering unit fails. In this embodiment, when the two electric power steering units are normal, the two electric power steering units jointly control the vehicle to steer, so that the effective resource utilization of the redundant electric power steering system can be realized.
(3) When the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units jointly control the vehicle to realize steering, and the peak torque of each motor does not need to reach the maximum torque required by the vehicle, so that the configuration requirement on the motor can be properly reduced, and the cost of the vehicle can be reduced on the premise of meeting the automatic driving safety.
(4) When any node (such as a processor, or a corner torque sensor, or a motor) in one electronic power steering unit fails, the other electronic power steering unit can also ensure driving safety under non-special working conditions.
As an example, when both the corner torque sensors, the two processors, and the two motors are normal, if the distribution mechanism is that the electronic power steering unit X3 outputs 0.3K, the electronic power steering unit Y1 outputs 0.7K, the electronic power steering unit X3 outputs a torque of 0.3K, and the electronic power steering unit Y1 outputs a torque of 0.7K.
As another example, when both the corner torque sensors, the two processors, and the two motors are normal, if the distribution mechanism is that the electronic power steering unit X3 outputs 0.7K, the electronic power steering unit Y1 outputs 0.3K, the electronic power steering unit X3 outputs 0.7K of torque, and the electronic power steering unit Y1 outputs 0.3K of torque.
As yet another example, when both the corner torque sensors, the two processors, and the two motors are normal, if the distribution mechanism is that the electronic power steering unit X3 outputs 0.4K, the electronic power steering unit Y1 outputs 0.6K, the electronic power steering unit X3 outputs 0.4K of torque, and the electronic power steering unit Y1 outputs 0.6K of torque.
As yet another example, when both the corner torque sensors, the two processors, and the two motors are normal, if the distribution mechanism is that the electronic power steering unit X3 outputs 0.6K, the electronic power steering unit Y1 outputs 0.4K, the electronic power steering unit X3 outputs 0.6K of torque, and the electronic power steering unit Y1 outputs 0.4K of torque.
As yet another example, when both of the steering angle torque sensors, the two processors, and the two motors are normal, if the distribution mechanism is that the two electric power steering units are equally distributed, the electric power steering unit X3 outputs a torque of 0.5K, and the electric power steering unit Y1 outputs a torque of 0.5K.
The advantages of each motor output of 0.5K are:
(1) When the two electronic power-assisted steering units are normal, each motor only outputs 0.5K, and the two electronic power-assisted steering units uniformly do work;
(2) When any one point in one electronic power steering unit fails, the other electronic power steering unit can be quickly lifted to the target value K by 0.5K, and the response speed is faster compared with that of lifting from 0 to the target value K, so that the system can ensure the driving safety of a vehicle.
When a processor in one of the electronic power steering units, or the steering angle torque sensor, or the motor fails, the other normal electronic power steering unit takes over the system to independently control the vehicle to realize steering.
As an example, when the processor in the electronic power steering unit Y1 fails, at this time, the system is taken over by the electronic power steering unit X3, and the vehicle is controlled individually to achieve steering.
As another example, when the steering angle torque sensor in the electronic power steering unit Y1 fails, at this time, the vehicle is controlled individually to achieve steering by the electronic power steering unit X3 taking over the system.
As yet another example, when the motor in the electric power steering unit X3 fails, at this time, the system is taken over by the electric power steering unit Y1, and the vehicle is controlled individually to achieve steering.
In this embodiment, the main braking unit 7 is configured to receive a control command from the bus, calculate the control command, and output a result. The slave brake unit 5 is configured to receive a control command from the bus and to calculate the control command, and to decide whether to execute the output of the result based on the status signal of the master brake unit 7.
As shown in fig. 3, the central controller 5 is further configured to issue control instructions, such as: a target deceleration signal and a target deceleration valid signal.
The main braking unit 7 is used for receiving and resolving the control command sent by the central controller 5, and executing the output of the result.
The slave brake unit 5 is configured to receive and interpret a control command issued from the central controller 5, and determine whether to execute the output of the result based on a status signal of the master brake unit 7.
Wherein: the master brake unit 7 and the slave brake unit 5 monitor each other whether the state signal of the other side indicates a failure (the manner of monitoring whether the other side is healthy is divided into passive monitoring and active monitoring, wherein the passive monitoring means that the failure information of the other side is received passively, and the active monitoring means that the failure information of the other side is acquired actively). In response to the state signals of the master brake unit 7 and the slave brake unit 5 being normal, the result output is performed by the master brake unit 7, and at this time, the slave brake unit 5 does not perform the result output. In response to monitoring that the status signal of the service brake unit 7 indicates that a failure has occurred (failure refers only to an unrecoverable failure occurring in the current ignition cycle, excluding a recoverable failure), a result output is performed by the slave brake unit 5. The output of the result is performed by the master brake unit 7 in response to monitoring that the status signal of the slave brake unit 5 indicates that a fault has occurred.
Example two
As shown in fig. 1, the redundant electric steering brake system also achieves redundancy of the automobile bus. The automobile buses comprise a first automobile bus 11 and a second automobile bus 4; the first automobile bus 11 is used for transmitting control instructions and feedback of state signals; the first car bus 11 is also used for transmitting currently desired steering wheel angle signals. The second bus 4 is used for transmitting the control command and feedback of the status signal synchronously with the first bus 11, and the second bus 4 is also used for transmitting the currently expected steering wheel angle signal.
The two electric power steering units, the master brake unit 7 and the slave brake unit 5 are each connected to a first motor vehicle bus 11.
The two electric power steering units, the master brake unit 7 and the slave brake unit 5 are also each connected to the second motor vehicle bus 4.
As shown in fig. 6, when one of the automobile buses fails, the other automobile bus can also ensure the normal operation of the system.
For the braking portion:
when the second car bus 4 fails in communication failure, the main brake unit 7 continues to maintain the brake control function, while a failure signal of the second car bus 4 will be sent to the central controller.
When the first car bus 11 fails in communication failure, the main brake unit 7 continues to maintain the brake control function, and at the same time will send a first car bus 11 failure signal to the central controller.
For the turning portion:
when a communication fault failure occurs on the first bus 11, the two electronic power steering units acquire the currently expected steering wheel angle signal from the second bus 4. While a first car bus 11 fault signal will be sent to the central controller.
When the second bus 4 fails in communication, the two electronic power steering units acquire the currently desired steering wheel angle signal from the first bus 11. And will send a second car bus 4 fault signal to the central controller.
The remainder is the same as in embodiment one.
Example III
As shown in fig. 1, the redundant electric steering brake system further includes a safety controller 8, i.e., redundancy of the controller is achieved.
The central controller 9 is respectively connected with the first automobile bus 11 and the second automobile bus 4, and the central controller 9 is used for calculating a current expected steering wheel angle signal, sending a control command, monitoring the working states of the master braking unit 7 and the slave braking unit 5, and respectively sending the current expected steering wheel angle signal and the control command to the first automobile bus 11 and the second automobile bus 4.
The safety controller 8 is respectively connected with the first automobile bus 11 and the second automobile bus 4; the safety controller 8 is configured to calculate a current desired steering wheel angle signal, and when it is detected that the central controller 9 is not disabled, not send the current desired steering wheel angle signal to the two processors, or add an invalid tag to the current desired steering wheel angle signal, and send the current desired steering wheel angle signal with the invalid tag to the two processors, so as to ensure that only one of the signals received by the two electronic power steering units is a valid signal. When the central controller 9 is monitored to be invalid, the safety controller 8 directly transmits the calculated current expected steering wheel angle signal to the first automobile bus 11 and the second automobile bus 4, so that when the central controller 9 is invalid, the two electronic power-assisted steering units can also receive the effective current expected steering wheel angle signal. The safety controller 8 is also used for sending control commands and monitoring the working states of the master brake unit 7 and the slave brake unit 5, and sending the control commands to the first automobile bus 11 and the second automobile bus 4 respectively.
As shown in fig. 4, the redundant electronic steering brake system realizes the redundancy of the controller, and when the central controller fails, the safety controller can also ensure the normal operation of the system.
The rest is the same as the embodiment
Example IV
As shown in fig. 1, the redundant electric steering brake system further includes a power supply unit 10; the power supply unit 10 includes a master power supply 10a and a slave power supply 10b. The main power supply 10a is electrically connected with the central controller 9, the main brake unit 7 and the electronic power steering unit X3 respectively; the secondary power supply 10b is electrically connected to the safety controller 8, the secondary brake unit 5 and the electronic power steering unit Y1, respectively, that is, redundancy of power supply is realized.
As shown in fig. 5, when the main power supply 10a fails, i.e., the network where the main brake unit 7 and the electronic power steering unit X3 are located is powered off, the slave brake unit 5 and the electronic power steering unit Y1 take over the system at this time, the brake and steering control functions are maintained, and a main power failure signal is sent to the safety controller.
When the slave power supply 10b fails, i.e. the network where the slave brake unit 5 and the electronic power steering unit Y1 are located is powered off, the system is taken over by the master brake unit 7 and the electronic power steering unit X3, the brake and steering control functions are maintained, and a slave power supply failure signal is sent out at the same time.
The rest is the same as the examples.
As shown in fig. 1, in the first to fourth embodiments, two processors are further connected through one or two first communication lines 2, and the two processors perform information interaction through the first communication lines 2, which is mainly used for mutual verification and fault monitoring of the calculation results between the two processors. Preferably, two first communication lines 2 are adopted, namely, redundancy of the first communication lines 2 is realized, and when one first communication line 2 fails, the other first communication line 2 can also ensure normal operation of the EPS system.
As shown in fig. 1, the master brake unit 7 and the slave brake unit 5 are also connected by a second communication line 6 for data interaction between the master brake unit 7 and the slave brake unit 5. The two monitor whether the other side fails (including the information of the health state and the calculation result) through the data interacted by the second communication line 6, if one brake unit fails, the other brake unit can find the failure in time and connect the system, so that the stability and reliability of the whole brake system are improved. The master brake unit 7 and the slave brake unit 5 may also be connected by two second communication lines 6, such as a proprietary CAN. The second communication lines 6 are redundant, and when one second communication line 6 fails, the other second communication line 6 can also ensure the normal operation of the brake system.
In the first to fourth embodiments, the main brake unit 7 includes a conventional brake system, an electronic stability program control system (i.e., ESP), an auxiliary deceleration control (i.e., CDD), an electronic hand brake control system (i.e., EPB), an automatic emergency brake (i.e., AEB), and an active brake assist system (i.e., BAS).
In the first to fourth embodiments, the slave brake unit 3 of the slave brake unit 5 is composed of a conventional brake system, a brake antilock brake system, an automatic emergency brake, and an auxiliary deceleration Control (CDD). The slave brake unit 5 may also consist of a conventional brake system, a brake anti-lock braking system (ABS) and an auxiliary deceleration control. Since the slave brake unit 5 is of a redundant design, it is only necessary to meet the basic braking requirements.
In the first to fourth embodiments, the first and second automobile buses 11 and 4 are both CAN buses, and Flexray buses may be used.
In the first to fourth embodiments, as shown in fig. 1, the brake control system for an autonomous vehicle further includes a first wheel speed sensor 12 and a second wheel speed sensor 13, the first wheel speed sensor 12 being connected to the master brake unit 7, and the second wheel speed sensor 13 being connected to the slave brake unit 5. Namely, the wheel speed sensors are also designed in a redundancy way, and when one wheel speed sensor fails, the other wheel speed sensor can also ensure the normal operation of the braking part.
In the first to fourth embodiments, the unrecoverable failure for the braking portion includes: braking pressure build-up failure, sensor signal interruption, system power failure and the like; recoverable failures include control commands, occasional frame loss of sensor data, short-time data verification errors, and the like.
In the first to fourth embodiments, the peak torque of each motor is 50% to 100% of the maximum torque B required for the vehicle (i.e., the torque required for turning the steering wheel to the limit turning angle when the vehicle is stationary) respectively, and when the vehicle is in a non-stationary state, even if one electric power steering unit fails, the other electric power steering unit can meet the steering requirement of the vehicle.
Preferably, the peak torque of each motor is 50% of the maximum torque value B required by the vehicle; the advantages are that: (1) When the whole braking system is normal, the added capacity of the two is B, so that the requirement of vehicle design can be met; (2) Experiments prove that under the condition of single-point failure, even if the peak torque of the motor is set to be 0.5B, a single electronic power-assisted steering unit can meet the steering requirement, except the power assistance required by the tail end of a static or ultra-low speed working condition, the automatic driving state belongs to a safe state when the vehicle is at a static or ultra-low speed, so that the system safety can be ensured by designing the peak torque of each motor to be 0.5B; (3) The higher the peak torque value of the motor is, the higher the cost configuration is, and the peak torque of each motor is designed to be 0.5B, so that the safety and the reliability of the system can be ensured, and the lowest cost configuration is realized; (4) if the peak torque of the two motors is different, for example; one peak torque is 0.3B and one peak torque is 0.7B, and when two motors with larger torques (such as 0.3B) are required to be simultaneously made, the motor with the peak torque of 0.3B needs to run at full load; while outputting a torque of 0.3B for a motor with a peak torque of 0.7B is very easy, this situation can lead to a motor with a peak torque of 0.3B being more prone to failure; in addition, if the motor with the peak torque of 0.7B fails, the motor with the peak torque of 0.3B cannot output the torque of 0.6B, so that when one single point fails, the system cannot ensure that the automatic driving is switched to the basic power assisting function of the human driving.
Claims (17)
1. A redundant electric steering brake system, characterized by comprising two electric power steering units, a master brake unit (7) and a slave brake unit (5);
the two electronic power steering units are used for jointly controlling the steering of the vehicle; each electronic power steering unit comprises a processor, and a corner torque sensor and a motor which are respectively connected with the processor; the corner torque sensor is used for outputting an actual torque signal and an angle signal of the current steering wheel and sending the actual torque signal and the angle signal to a processor connected with the angle signal; the processor is used for acquiring a currently expected steering wheel angle signal from the automobile bus; the processor is also used for calculating a total torque value K which is required to be output currently of the whole system according to a currently expected steering wheel angle signal and an angle signal obtained from the angle torque sensor, and calculating torque values which are required to be output by the respective electronic power steering units according to a distribution mechanism; the processor also controls a motor correspondingly connected with the processor according to the torque value to control the vehicle to realize steering;
wherein, the allocation mechanism is as follows: when the two electronic power-assisted steering units are normal, the two electronic power-assisted steering units work simultaneously, the corresponding motors are controlled to work according to the torque values required to be output respectively, the vehicles are controlled to realize steering together, and the torque values required to be output by the two electronic power-assisted steering units meet the following formula: a+b=k, and a is more than or equal to 0.3K and less than or equal to 0.7K, a is a torque value currently required to be output by one of the electronic power steering units, and b is a torque value currently required to be output by the other electronic power steering unit; when a processor in one of the electronic power steering units, or a corner torque sensor or a motor fails, the other normal electronic power steering unit takes over the system to independently control the vehicle to realize steering;
the main braking unit (7) is used for receiving and resolving the control instruction and outputting an execution result;
the slave brake unit (5) is used for receiving and resolving the control instruction and deciding whether to execute the output of the result or not based on the state signal of the master brake unit (7);
wherein: the main braking unit (7) and the auxiliary braking unit (5) monitor each other whether the opposite side state signal represents faults; in response to the state signal of the main brake unit (7) being normal, performing a result output by the main brake unit (7), at which time no result output is performed from the brake unit (5); and in response to the state signal of the main braking unit (7) being a fault failure, executing a result output by the auxiliary braking unit (5).
2. The redundant electric steering brake system of claim 1, wherein: when both electronic power steering units are normal, the a satisfies: a is more than or equal to 0.4K and less than or equal to 0.6K.
3. The redundant electric steering brake system of claim 2, wherein: when both electronic power steering units are normal, the a satisfies: a=0.5k.
4. A redundant electric steering brake system according to any one of claims 1 to 3, wherein: the automobile bus comprises:
the first automobile bus (11), the two electronic power steering units, the main braking unit (7) and the auxiliary braking unit (5) are connected with the first automobile bus (11);
and the second automobile bus (4), and the two electronic power steering units, the master braking unit (7) and the slave braking unit (5) are connected with the second automobile bus (4).
5. The redundant electric steering brake system of claim 4, further comprising:
the central controller (9) is respectively connected with the first automobile bus (11) and the second automobile bus (4), and the central controller (9) is used for calculating a current expected steering wheel angle signal, sending a control command, monitoring state signals of the master braking unit (7) and the slave braking unit (5) and sending the current expected steering wheel angle signal and the control command to the first automobile bus (11) and the second automobile bus (4) respectively.
6. The redundant electric steering brake system of claim 5, further comprising:
the safety controller (8) is respectively connected with the first automobile bus (11) and the second automobile bus (4);
the safety controller (8) is used for calculating a current expected steering wheel angle signal, and when the central controller (9) is monitored to be not invalid, the current expected steering wheel angle signal is not sent to the two processors, or an invalid label is added to the current expected steering wheel angle signal, and the current expected steering wheel angle signal with the invalid label is sent to the two processors; when the failure of the central controller (9) is monitored, the safety controller (8) directly transmits the calculated current expected steering wheel angle signal to the first automobile bus (11) and the second automobile bus (4);
and for transmitting control commands and monitoring status signals of the master brake unit (7) and the slave brake unit (5) and for transmitting the control commands to the first vehicle bus (11) and the second vehicle bus (4), respectively.
7. The redundant electric steering brake system of claim 6, further comprising a power supply unit (10);
the power supply unit (10) includes a master power supply (10 a) and a slave power supply (10 b);
the main power supply (10 a) is respectively and electrically connected with the central controller (9), the main braking unit (7) and one of the electronic power steering units;
the secondary power supply (10 b) is electrically connected with the safety controller (8), the secondary braking unit (5) and the other electronic power steering unit respectively.
8. The redundant electric steering brake system of claim 1 or 2 or 3 or 5 or 6 or 7, wherein:
the processors of the two electronic power steering units are also connected through one or two first communication lines (2);
the master brake unit (7) and the slave brake unit (5) are also connected by one or two second communication lines (6).
9. The redundant electric steering brake system of claim 8, wherein: the peak torque of the motor of each electronic power steering unit is 50% -100% of the maximum torque value B required by the vehicle respectively.
10. The redundant electric steering brake system of claim 1 or 2 or 3 or 5 or 6 or 7, wherein: the peak torque of the motor of each electronic power steering unit is 50% -100% of the maximum torque value B required by the vehicle respectively.
11. The redundant electric steering brake system of claim 4, wherein: the peak torque of the motor of each electronic power steering unit is 50% -100% of the maximum torque value B required by the vehicle respectively.
12. The redundant electric steering brake system of claim 8, wherein: the peak torque of the motor of each electric power steering unit is 50% of the maximum torque value B required for the vehicle, respectively.
13. The redundant electric steering brake system of claim 1 or 2 or 3 or 5 or 6 or 7 or 9, wherein: the peak torque of the motor of each electric power steering unit is 50% of the maximum torque value B required for the vehicle, respectively.
14. The redundant electric steering brake system of claim 4, wherein: the peak torque of the motor of each electric power steering unit is 50% of the maximum torque value B required for the vehicle, respectively.
15. The redundant electric steering brake system of claim 1 or 2 or 3 or 5 or 6 or 7 or 9 or 14, wherein: when a processor in one of the electronic power steering units, or the corner torque sensor or the motor fails, the other normal electronic power steering unit controls the corresponding motor to work according to the total torque value K which is required to be output currently by the whole system.
16. The redundant electric steering brake system of claim 8, wherein: when a processor in one of the electronic power steering units, or the corner torque sensor or the motor fails, the other normal electronic power steering unit controls the corresponding motor to work according to the total torque value K which is required to be output currently by the whole system.
17. The redundant electric steering brake system of claim 4, wherein: when a processor in one of the electronic power steering units, or the corner torque sensor or the motor fails, the other normal electronic power steering unit controls the corresponding motor to work according to the total torque value K which is required to be output currently by the whole system.
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| KR102167906B1 (en) * | 2019-06-20 | 2020-10-20 | 주식회사 만도 | Apparatus for controlling steering and System for assisting steering including it |
| CN110712677B (en) * | 2019-11-29 | 2024-02-27 | 吉林大学 | Redundant electric power steering system of automatic driving vehicle and control method thereof |
| CN111038480B (en) * | 2019-12-12 | 2021-05-18 | 苏州智加科技有限公司 | Automatic driving execution system and automatic driving control command execution method |
| CN113460152B (en) * | 2020-03-31 | 2023-03-03 | 华为技术有限公司 | Electric power steering device and control method thereof |
| CN111762260B (en) * | 2020-06-22 | 2021-11-19 | 北京汽车股份有限公司 | Power-assisted steering system redundancy control system and method based on calibrated vehicle speed and vehicle |
| EP4257453A1 (en) * | 2020-12-25 | 2023-10-11 | Huawei Technologies Co., Ltd. | Control method, monitoring method, electronic control units, controller and control system |
| CN112896128A (en) * | 2021-02-08 | 2021-06-04 | 一汽解放汽车有限公司 | Braking system |
| CN113459832A (en) * | 2021-08-13 | 2021-10-01 | 爱思盟汽车科技(重庆)有限公司 | Circuit system of vehicle power chassis |
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