Independent redundant wheel speed processing system and method

Abstract

An independent redundant wheel speed processing system, comprising four wheel speed sensors (1, 2, 3, 4) respectively provided on four wheels, the four wheel speed sensors (1, 2, 3, 4) being in communication connection to an MCU by means of four wheel speed signal processing units respectively. The four wheel speed signal processing units respectively perform diagnosis of driving anomalies and wheel speed signal anomalies of the four wheel speed sensors (1, 2, 3, 4) and send to the MCU diagnosis results. Thus, using the independent wheel speed signal processing units can ensure the function safety requirement and the function redundancy requirement of brake systems, thereby reducing the high cost of brake systems. Further provided is an independent redundant wheel speed processing method based on the independent redundant wheel speed processing system.

Description

Independent redundant wheel speed processing system and method Technical Field

[0001] The present invention belongs to the field of vehicle control, and more particularly, to an independent redundant wheel speed processing system and method. Background Art

[0002] In order to realize the vehicle's driving brake control, parking brake control and body stability control functions, the vehicle braking system's brake controller needs to detect the four wheel speed signals input by the vehicle's four wheel speed sensors. After processing and monitoring the input signals, each sub-functional module calculates the four wheel speeds, vehicle speed and slip rate results based on the input processed signals, and outputs drive actuators and signals to drive other actuators to operate.

[0003] To meet functional safety requirements, the wheel speed sensor detection circuit within the brake controller must meet functional safety requirements in terms of diagnostic coverage and hardware failure rate. Vehicles equipped with autonomous driving capabilities will require functional redundancy in the braking system, necessitating a redundant design for the wheel speed sensors as well.

[0004] The existing design uses a highly integrated wheel speed acquisition chip. Each highly integrated wheel speed acquisition chip collects four wheel speed signals from four wheel speed sensors. When the highly integrated wheel speed acquisition chip fails, the four wheel speed signals of the four wheel speed sensors connected to it cannot be obtained. In order to meet the requirements of functional redundancy, the vehicle uses two highly integrated wheel speed acquisition chips and arranges eight wheel speed sensors on the vehicle, with two wheel speed sensors on each wheel, as shown in Figure 1. By increasing hardware to meet functional safety and functional redundancy, the cost of the vehicle's braking system is greatly increased.

[0005] Summary of the Invention

[0006] The present invention provides an independent redundant wheel speed processing system, aiming to improve the above-mentioned problem.

[0007] The present invention is implemented as follows: an independent redundant wheel speed processing system, the system comprising:

[0008] Four wheel speed sensors are installed on each of the four wheels;

[0009] The four wheel speed sensors are connected to the MCU through four wheel speed signal processing units respectively;

[0010] The four wheel speed signal processing units diagnose the driving abnormalities and wheel speed signal abnormalities of the four wheel speed sensors respectively, and send the diagnosis results and the wheel speed signals output by the corresponding wheel speed sensors to the MCU.

[0011] Furthermore, the wheel speed signal processing unit includes: a drive diagnosis module for diagnosing drive abnormalities of the corresponding wheel speed sensor, the drive diagnosis module includes: a high-side drive diagnosis submodule and a low-side drive diagnosis submodule, wherein,

[0012] The high-side driver diagnosis submodule performs high-side driver fault diagnosis of the wheel speed sensor based on the high-side voltage;

[0013] The low-side driver diagnosis submodule performs fault diagnosis on the output signal of the wheel speed sensor based on the acquisition circuit. Each wheel sensor is equipped with an independent power supply circuit and acquisition circuit. The power supply circuit is used to power the wheel speed sensor, and the acquisition circuit is used to collect the wheel speed signal.

[0014] Furthermore, the high-side driver diagnosis method is as follows:

[0015] An ADC sampling circuit is provided on the high side of each wheel speed sensor to sample the ADC value of the corresponding wheel speed sensor voltage. The operating voltage corresponding to the sampled ADC value is verified with the reference voltage value output by the MCU to detect whether the current operating voltage of the wheel speed sensor is within the valid operating voltage range. If the operating voltage of the wheel speed sensor is within the valid operating voltage range, it is determined that the high-side drive of the corresponding wheel speed sensor is normal.

[0016] Furthermore, the wheel speed signal processing unit includes a wheel speed diagnosis module for diagnosing abnormal wheel speed signals, wherein the wheel speed signal diagnosis method is specifically as follows:

[0017] An ADC acquisition circuit is set at the interface for inputting wheel speed pulses to collect the wheel speed pulse signal output by the wheel speed sensor, and the amplitude of the collected wheel speed pulse signal is diagnosed. If the amplitude of the wheel speed pulse signal is within the set amplitude range, the wheel speed signal output by the wheel speed sensor is deemed valid.

[0018] Furthermore, a wheel speed signal verification module is integrated into the MCU to receive the valid wheel speed signals sent by the four wheel speed signal processing units and perform verification based on the valid wheel speed signals.

[0019] Furthermore, the verification process of the effective wheel speed signal is as follows:

[0020] Read the effective wheel speed signals during uniform speed driving, detect the deviation of each wheel speed signal relative to other wheel speed signals, and if the deviation exceeds the set deviation threshold, the wheel speed sensor signal corresponding to the wheel speed signal is deemed invalid.

[0021] Furthermore, the system includes:

[0022] Two MCUs, namely a master MCU and a slave MCU, and the output ends of the four wheel speed signal processing units are connected to the master MCU and the slave MCU respectively;

[0023] Among them, the master MCU and the slave MCU calculate the wheel speed signal of the corresponding wheel speed sensor based on the valid wheel speed pulse signal output by the wheel speed signal verification module.

[0024] Furthermore, the slave MCU will calculate the wheel speed signal of the corresponding wheel speed sensor based on the valid wheel speed pulse signal and send it to the master MCU; if the wheel speed signals calculated by the master MCU and the slave MCU are the same, it is determined that the master MCU has no fault.

[0025] The present invention is implemented as follows: an independent redundant wheel speed processing method based on the above-mentioned independent redundant wheel speed processing system, the method comprising the following steps:

[0026] S1. Collect high-side voltage signals from four wheel speed sensors and output signals from an acquisition circuit. Detect whether the wheel speed sensors have a high-side driver fault based on the high-side voltage signals. Detect whether the acquisition circuit has a low-side driver fault based on the output signals from the acquisition circuit.

[0027] S2. If a high-side drive fault and / or a low-side drive fault exists, the corresponding wheel speed sensor is determined to be faulty. For wheel speed sensors that do not have a high-side drive fault or a low-side drive fault, step S3 is executed.

[0028] S3, detecting whether the wheel speed information output by the wheel speed sensor is valid. If the detection result is yes, proceeding to step S4; if the detection result is no, determining that the corresponding wheel speed sensor status and signal are faulty;

[0029] S4. The MCU verifies the valid wheel speed information, detects the invalid wheel speed signal, and determines that the wheel speed sensor corresponding to the invalid wheel speed signal is faulty.

[0030] The present invention adopts an independent and discrete wheel speed signal processing unit, which ensures the functional safety requirements and functional redundancy requirements of the braking system, while reducing the high cost of the braking system adopting a highly integrated chip to meet the functional safety and functional redundancy requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a block diagram of the hardware architecture of an existing wheel speed sensor interface provided by an embodiment of the present invention;

[0032] FIG2 is a schematic diagram of the structure of an independent redundant wheel speed processing system under a single MCU provided by an embodiment of the present invention;

[0033] FIG3 is a schematic diagram of the structure of an independent redundant wheel speed processing system under dual MCUs provided in an embodiment of the present invention;

[0034] FIG4 is a flow chart of an independent redundant wheel speed processing method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The specific implementation methods of the present invention will be further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0036] FIG2 is a schematic diagram of the structure of an independent redundant wheel speed processing system provided by an embodiment of the present invention. For the purpose of illustration, only the parts relevant to the embodiment of the present invention are shown. The system includes:

[0037] Four wheel speed sensors are respectively provided on the four wheels, including wheel speed sensor 1, wheel speed sensor 2, wheel speed sensor 3 and wheel speed sensor 4. The four wheel speed sensors are respectively connected to the MCU through four wheel speed signal processing units;

[0038] The four wheel speed signal processing units diagnose the driving abnormalities and wheel speed signal abnormalities of the four wheel speed sensors respectively, and send the diagnosis results and the wheel speed signals output by the corresponding wheel speed sensors to the MCU.

[0039] In an embodiment of the present invention, four wheel speed sensors correspond to four wheel speed signal processing units. Each wheel speed signal processing unit includes: a drive diagnostic module and a wheel speed diagnostic module, which are respectively used to diagnose drive abnormalities and wheel speed signal abnormalities of the corresponding wheel speed sensors, and upload the diagnostic results to the MCU.

[0040] The driver diagnosis module includes a high-side driver diagnosis submodule and a low-side driver diagnosis submodule, wherein:

[0041] (1) High-side driver diagnosis submodule: performs high-side driver diagnosis of the wheel speed sensor based on the high-side voltage;

[0042] An ADC sampling circuit is designed on the high side of the wheel speed sensor to sample the ADC value of the corresponding wheel speed sensor voltage. The operating voltage corresponding to the sampled ADC value is verified with the reference voltage value output by the MCU to detect whether the current operating voltage of the wheel speed sensor is within the valid operating voltage range. If the operating voltage of the wheel speed sensor is within the valid operating voltage range, it is determined that the high-side drive of the corresponding wheel speed sensor is normal.

[0043] (2) Low-side drive diagnosis submodule: performs low-side drive fault diagnosis of the wheel speed sensor based on the output information of the acquisition circuit;

[0044] The system includes: four power supply circuits for four wheel speed sensors, and four acquisition circuits for collecting four wheel speed signals. When one of the acquisition circuits and / or power supply circuits fails, it will not affect the power supply and wheel speed signal collection of the other three wheel speed sensors.

[0045] The acquisition circuit fault is diagnosed through the low-side driver diagnosis submodule. The four wheel speed sensors correspond to four low-side driver diagnosis submodules.

[0046] (3) Wheel speed signal diagnosis based on wheel speed diagnosis module

[0047] An ADC acquisition circuit is designed at the interface of the wheel speed pulse input to collect the wheel speed pulse signal output by the wheel speed sensor and diagnose the amplitude of the wheel speed pulse signal. If the amplitude of the wheel speed pulse signal is within the set amplitude range, the wheel speed signal output by the wheel speed sensor is deemed valid and the corresponding wheel speed sensor pulse drive is deemed normal.

[0048] In an embodiment of the present invention, a wheel speed signal verification module is integrated in the MCU, which receives the valid wheel speed signals sent by the four wheel speed signal processing units and verifies the valid wheel speed signals. The verification process is as follows: the valid wheel speed signals during uniform speed driving are read, and the deviation of each wheel speed signal relative to other wheel speed signals is detected. If the deviation exceeds the set deviation threshold, the wheel speed sensor signal corresponding to the wheel speed signal is deemed invalid, that is, the wheel speed signal is deemed not the actually collected wheel speed signal and is an invalid wheel speed signal.

[0049] FIG3 is a schematic diagram of the structure of an independent redundant wheel speed processing system under dual MCUs according to an embodiment of the present invention. For the sake of illustration, only the parts related to the embodiment of the present invention are shown. The system includes:

[0050] Two MCUs, namely a master MCU and a slave MCU, and the output ends of the four wheel speed signal processing units are connected to the master MCU and the slave MCU respectively;

[0051] Among them, the main MCU calculates the wheel speed signal of the corresponding wheel speed sensor based on the valid wheel speed pulse signal output by the wheel speed signal verification module;

[0052] The slave MCU calculates the speed signal of the corresponding wheel speed sensor based on the effective wheel speed pulse signal output by the wheel speed signal verification module, and at the same time calculates the speed direction, and sends the detected speed signal and speed direction of the wheel speed sensor to the main MCU to verify the wheel speed signal. When the wheel speed signals calculated by the two are the same, it is determined that the main MCU has no fault.

[0053] In the embodiment of the present invention, since there is a lot of speed direction information

[0054] When the master MCU fails, if the slave MCU is normal, the slave MCU can still process the valid wheel speed pulse signal output by the wheel speed signal processing unit and output it to the required electronic control unit through the CAN interface.

[0055] The independent redundant wheel speed processing system provided by the present invention has the following beneficial technical effects:

[0056] (1) The design of four independent wheel speed signal processing units replaces the high-integration chip to collect wheel speed signals. From the perspective of functional safety, the wheel speed signal validity and synchronization are met. The wheel speed signal is diagnosed through software algorithms, and the four-way discrete design filters out the correlation interference of the wheel speed sensor signal to meet the independence requirements. A set of safety mechanism designs that meet functional safety is provided, and the timeliness of wheel speed signal fault diagnosis is improved. After executing functional degradation, the fault information will be sent to the HMI, and finally the fault information will be displayed on the instrument to warn the driver and the system enters a safe state. (2) From the perspective of functional redundancy, the four wheel speed sensor interfaces use four independent sensor interface circuits and two MCUs for redundant signal processing. Even if a single wheel speed sensor or acquisition circuit fails, the validity of the three-way wheel speed sensor signal can still be guaranteed. Even if a single MCU fails, the validity of the four-way wheel speed signal can still be guaranteed. After meeting the requirements of the braking system for functional safety and functional redundancy, the cost of the vehicle's brake electronic control unit system is reduced.

[0057] FIG4 is a flow chart of an independent redundant wheel speed processing method according to an embodiment of the present invention. The method specifically includes the following steps:

[0058] S1. Collect high-side voltage signals from four wheel speed sensors and output signals from an acquisition circuit. Detect whether the wheel speed sensors have a high-side driver fault based on the high-side voltage signals. Detect whether the acquisition circuit has a low-side driver fault based on the output signals from the acquisition circuit.

[0059] S2. If a high-side drive fault and / or a low-side drive fault exists, the corresponding wheel speed sensor is determined to be faulty. For wheel speed sensors that do not have a high-side drive fault or a low-side drive fault, step S3 is executed.

[0060] S3, detecting whether the wheel speed information output by the wheel speed sensor is valid. If the detection result is yes, proceeding to step S4; if the detection result is no, determining that the corresponding wheel speed sensor status and signal are faulty;

[0061] S4. The MCU verifies the valid wheel speed information, detects the invalid wheel speed signal, and determines that the wheel speed sensor corresponding to the invalid wheel speed signal is faulty.

[0062] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. An independent redundant wheel speed processing system, characterized in that: The system comprises: Four wheel speed sensors are respectively arranged on four wheels; The four wheel speed sensors are respectively connected to the MCU through four wheel speed signal processing units; The four wheel speed signal processing units diagnose the driving abnormalities and wheel speed signal abnormalities of the four wheel speed sensors respectively, and send the diagnosis results and the wheel speed signals output by the corresponding wheel speed sensors to the MCU.

2. The independent redundant wheel speed processing system according to claim 1, characterized in that: The wheel speed signal processing unit includes: a drive diagnosis module for diagnosing drive abnormalities of the corresponding wheel speed sensor, the drive diagnosis module includes: a high-side drive diagnosis submodule and a low-side drive diagnosis submodule, wherein: The high-side driver diagnosis submodule performs high-side driver fault diagnosis of the wheel speed sensor based on the high-side voltage; The low-side drive diagnosis submodule performs fault diagnosis on the output signal of the wheel speed sensor based on the acquisition circuit, wherein each wheel sensor is configured with an independent power supply circuit and an acquisition circuit. The power supply circuit is used to power the wheel speed sensor, and the acquisition circuit is used to acquire the wheel speed signal.

3. The independent redundant wheel speed processing system as claimed in claim 2, characterized in that: The high-side driver diagnosis method is as follows: An ADC sampling circuit for sampling the ADC value of the corresponding wheel speed sensor voltage is provided on the high side of each wheel speed sensor. The working voltage corresponding to the sampled ADC value is verified with the reference voltage value output by the MCU to detect whether the current working voltage of the wheel speed sensor is within the valid working voltage range. If the working voltage of the wheel speed sensor is within the valid working voltage range, it is determined that the high side drive of the corresponding wheel speed sensor is normal.

4. The independent redundant wheel speed processing system according to claim 1, characterized in that: The wheel speed signal processing unit includes a wheel speed diagnosis module for diagnosing abnormal wheel speed signals, wherein the wheel speed signal diagnosis method is specifically as follows: An ADC acquisition circuit for collecting the wheel speed pulse signal output by the wheel speed sensor is set at the interface of the input wheel speed pulse, and the amplitude of the collected wheel speed pulse signal is diagnosed. If the amplitude of the wheel speed pulse signal is within the set amplitude range, the wheel speed signal output by the wheel speed sensor is deemed valid.

5. The independent redundant wheel speed processing system according to claim 1, characterized in that: The MCU is integrated with a wheel speed signal verification module, which receives the valid wheel speed signals sent by the four wheel speed signal processing units and verifies the valid wheel speed signals.

6. The independent redundant wheel speed processing system as claimed in claim 5, characterized in that: The verification process of the effective wheel speed signal is as follows: The effective wheel speed signal during uniform speed driving is read, and the deviation of each wheel speed signal relative to other wheel speed signals is detected. If the deviation exceeds the set deviation threshold, the wheel speed sensor signal corresponding to the wheel speed signal is deemed invalid.

7. The independent redundant wheel speed processing system according to claim 1, characterized in that: The system includes: Two MCUs, namely a master MCU and a slave MCU, and output ends of four wheel speed signal processing units are connected to the master MCU and the slave MCU respectively; The master MCU and the slave MCU calculate the wheel speed signal of the corresponding wheel speed sensor based on the effective wheel speed pulse signal output by the wheel speed signal verification module.

8. The independent redundant wheel speed processing system as claimed in claim 7, characterized in that: The slave MCU will calculate the wheel speed signal of the corresponding wheel speed sensor based on the effective wheel speed pulse signal and send it to the master MCU; if the wheel speed signals calculated by the master MCU and the slave MCU are the same, it is determined that the master MCU has no fault.

9. An independent redundant wheel speed processing method based on the independent redundant wheel speed processing system according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: S1. Collect high-side voltage signals of four wheel speed sensors and output signals of the acquisition circuit, detect whether the wheel speed sensor has a high-side drive fault based on the high-side voltage signal, and detect whether the acquisition circuit has a low-side drive fault based on the output signal of the acquisition circuit; S2. If there is a high-side drive fault and / or a low-side drive fault, the corresponding wheel speed sensor is determined to be faulty. For the wheel speed sensor that does not have a high-side drive fault and a low-side drive fault, step S3 is executed; S3, detecting whether the wheel speed information output by the wheel speed sensor is valid, if the detection result is yes, proceeding to step S4, if the detection result is no, determining that the corresponding wheel speed sensor state and signal failure; S4. MCU verifies the valid wheel speed information, detects the failed wheel speed signal, and determines that the wheel speed sensor corresponding to the failed wheel speed signal is faulty.

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