Independent redundant wheel speed processing system and independent redundant wheel speed processing method

Abstract

The present invention provides an independent redundant wheel speed processing system. The system includes four wheel speed sensors (1, 2, 3, 4) installed on four wheels, each of which is connected to an MCU via four wheel speed signal processing units. The four wheel speed signal processing units diagnose the drive abnormalities and wheel speed signal abnormalities of the four wheel speed sensors (1, 2, 3, 4) and send the diagnosis results to the MCU. By adopting independent wheel speed signal processing units, the present invention can ensure the functional safety and functional redundancy requirements of the brake system while reducing the high cost of the brake system. The present invention also provides an independent redundant wheel speed processing method based on the independent redundant wheel speed processing system.

Description

[Technical Field]

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

[0002] In the vehicle brake system, to realize the vehicle's traveling brake control, parking brake control, and vehicle body stability control functions, the brake controller detects four wheel speed signals input from the vehicle's four wheel speed sensors, processes and monitors the input signals, and then each sub-function module calculates the four wheel speeds, vehicle speed, and slip ratio based on the input processed signals, and outputs signals based on the calculation results to drive and operate the brakes and other actuators.

[0003] To meet functional safety requirements, the wheel speed sensor detection circuit inside the brake controller must meet the functional safety requirements in terms of diagnostic coverage rate and hardware failure rate.Vehicles equipped with autonomous driving functions require functional redundancy in the brake system, and the wheel speed sensors also need to be designed with redundancy.

[0004] In conventional designs, highly integrated wheel speed sampling chips are used, with each chip sampling four wheel speed signals from four wheel speed sensors. However, if one of the highly integrated wheel speed sampling chips fails, the four wheel speed signals from the four connected wheel speed sensors cannot be sampled. To meet the requirement for functional redundancy, as shown in Figure 1, two highly integrated wheel speed sampling chips are used in a vehicle, resulting in eight wheel speed sensors throughout the vehicle, with two wheel speed sensors per wheel. While this increased hardware meets functional safety and functional redundancy requirements, it also significantly increases the cost of the vehicle's overall braking system. Summary of the Invention

[0005] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an independent and redundant wheel speed processing system.

[0006] The independent and redundant wheel speed processing system of the present invention includes four wheel speed sensors, one for each of the four wheels.

[0007] The four wheel speed sensors are connected to the MCU via four wheel speed signal processing units, respectively.

[0008] The four wheel speed signal processing units diagnose the four wheel speed sensors for drive abnormalities and wheel speed signal abnormalities, respectively, and send the diagnosis results and the wheel speed signals output from the corresponding wheel speed sensors to the MCU.

[0009] Furthermore, the wheel speed signal processing unit includes a driving diagnostic module for diagnosing driving abnormalities of the corresponding wheel speed sensor, and the driving diagnostic module includes a high-side driving diagnostic sub-module and a low-side driving diagnostic sub-module.

[0010] The high side drive diagnostic sub-module diagnoses high side drive failure of the wheel speed sensor based on the high side voltage.

[0011] The low-side driving diagnostic sub-module performs fault diagnosis on the output signals of the wheel speed sensors based on the sampling circuits, where each wheel speed sensor is provided with an independent power supply circuit and sampling circuit, the power supply circuit is used to supply power to the wheel speed sensor, and the sampling circuit is used to sample the wheel speed sensor signal.

[0012] Furthermore, an ADC sampling circuit is provided on the high side of each wheel speed sensor to sample the ADC value of the voltage of the corresponding wheel speed sensor.The operating voltage corresponding to the ADC value sampled by the ADC sampling circuit is compared with a reference voltage value output from the MCU to detect whether the current operating voltage of the wheel speed sensor is within a 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, thereby performing high side drive diagnosis.

[0013] The wheel speed signal processing unit further includes a wheel speed diagnosis module that diagnoses abnormalities in the wheel speed signal. An interface to which the wheel speed pulse is input is provided with an ADC sampling circuit that samples the wheel speed pulse signal output from the wheel speed sensor. The wheel speed signal is diagnosed by diagnosing the amplitude of the sampled wheel speed pulse signal and determining that the wheel speed signal output from the wheel speed sensor is valid if the amplitude of the wheel speed pulse signal is within a set amplitude range.

[0014] In addition, the MCU is integrated with a wheel speed signal verification module, which receives valid wheel speed signals sent from the four wheel speed signal processing units and verifies them against valid wheel speed signals.

[0015] Furthermore, valid wheel speed signals are read out during constant speed driving, and deviations of each wheel speed signal relative to other wheel speed signals are detected. If all deviations exceed a set deviation threshold, the wheel speed sensor signal corresponding to that wheel speed signal is determined to be invalid, thereby verifying the valid wheel speed signals.

[0016] Furthermore, the independent and redundant wheel speed processing system includes two MCUs, namely, a master MCU and a slave MCU. The output ends of the four wheel speed signal processing units are connected to the master MCU and the slave MCU, respectively. The master MCU and the slave MCU respectively calculate the wheel speed signals of the corresponding wheel speed sensors according to the valid wheel speed pulse signals output from the wheel speed signal verification module.

[0017] Furthermore, the slave MCU calculates the wheel speed signal of the corresponding wheel speed sensor based on the valid wheel speed pulse signal and sends it to the master MCU. If the wheel speed signals calculated by the master MCU and the slave MCU are consistent, it is determined that the master MCU is not faulty.

[0018] The independent redundant wheel speed processing method based on the independent redundant wheel speed processing system according to the present invention includes the following steps S1 to S4.

[0019] In step S1, the high-side voltage signals of the four wheel speed sensors and the output signals of the sampling circuits are sampled, and it is determined whether a high-side drive fault exists in the wheel speed sensors based on the high-side voltage signals, and whether a low-side drive fault exists in the sampling circuit based on the output signals of the sampling circuits.

[0020] In step S2, if a high-side drive failure and / or a low-side drive failure exists, it is determined that the corresponding wheel speed sensor has failed, and step S3 is executed for the wheel speed sensors that do not have a high-side drive failure or a low-side drive failure.

[0021] In step S3, it is detected whether the wheel speed information output from the wheel speed sensor is valid. If the detection result is YES, the process proceeds to step S4. If the detection result is NO, it is determined that the state and signal of the corresponding wheel speed sensor have failed.

[0022] In step S4, the MCU verifies the valid wheel speed information, detects an invalid wheel speed signal, and determines that a fault exists in the wheel speed sensor corresponding to the invalid wheel speed signal. [Effects of the Invention]

[0023] By adopting an independent wheel speed signal processing unit, the present invention can meet the functional safety and functional redundancy requirements of the brake system, and reduce the high costs incurred when using a highly integrated chip to achieve the functional safety and functional redundancy of the brake system. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram of the hardware architecture of a conventional wheel speed sensor interface in accordance with an embodiment of the present invention. [Figure 2] 1 is a structural schematic diagram of an independent and redundant wheel speed processing system using a single MCU according to an embodiment of the present invention; [Figure 3] 1 is a structural schematic diagram of an independent and redundant wheel speed processing system using dual MCUs according to an embodiment of the present invention; [Figure 4] 3 is a flowchart of an independent and redundant wheel speed processing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] DETAILED DESCRIPTION OF THE INVENTION In order to enable those skilled in the art to understand the inventive concepts and technical solutions of the present invention more completely, accurately and profoundly, specific embodiments of the present invention will be described in more detail below through examples with reference to the drawings.

[0026] 2 is a structural schematic diagram of an independent and redundant wheel speed processing system according to an embodiment of the present invention, and for the sake of explanation, only the relevant parts are shown. The independent and redundant wheel speed processing system includes four wheel speed sensors (i.e., wheel speed sensor 1, wheel speed sensor 2, wheel speed sensor 3, and wheel speed sensor 4) installed on four wheels, respectively, and the four wheel speed sensors are connected to the MCU via four wheel speed signal processing units, respectively.

[0027] The four wheel speed signal processing units diagnose the four wheel speed sensors for drive abnormalities and wheel speed signal abnormalities, respectively, and send the diagnosis results and the wheel speed signals output from the corresponding wheel speed sensors to the MCU.

[0028] In an embodiment of the present invention, the four wheel speed sensors correspond to four wheel speed signal processing units, and each wheel speed signal processing unit includes a driving diagnosis module and a wheel speed diagnosis module for diagnosing driving abnormalities and wheel speed signal abnormalities of the corresponding wheel speed sensor and uploading the diagnosis results to the MCU.

[0029] The driving diagnostic module includes a high-side driving diagnostic sub-module and a low-side driving diagnostic sub-module.

[0030] (1) The high-side drive diagnostic submodule diagnoses high-side drive of the wheel speed sensor based on the high-side voltage.

[0031] An ADC sampling circuit is provided on the high side of the wheel speed sensor, sampling the ADC value of the voltage of the corresponding wheel speed sensor. The operating voltage corresponding to the ADC value sampled by the ADC sampling circuit is compared with a reference voltage value output from the MCU to determine whether the current operating voltage of the wheel speed sensor is within a 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.

[0032] (2) The low-side drive diagnostic submodule diagnoses low-side drive failures of the wheel speed sensor based on the output information of the sampling circuit.

[0033] The system includes four power supply circuits for supplying power to the four wheel speed sensors and four sampling circuits for sampling the four wheel speed signals, and if one of the sampling circuits and / or power supply circuits fails, it does not affect the power supply to the other three wheel speed sensors or the sampling of the wheel speed signals.

[0034] Sampling circuit failures are diagnosed by the low-side drive diagnostic sub-module. The four wheel speed sensors correspond to four low-side drive diagnostic sub-modules.

[0035] (3) Wheel speed signal diagnosis is performed by the wheel speed diagnostic module.

[0036] An ADC sampling circuit is provided at the interface to which the wheel speed pulse is input, and samples the wheel speed pulse signal output from the wheel speed sensor.The amplitude of the wheel speed pulse signal is diagnosed, and if the amplitude of the wheel speed pulse signal is within a set amplitude range, it is determined that the wheel speed signal output from the wheel speed sensor is valid and the pulse drive of the corresponding wheel speed sensor is normal.

[0037] In an embodiment of the present invention, a wheel speed signal verification module is integrated into the MCU to receive valid wheel speed signals sent from the four wheel speed signal processing units and verify whether the wheel speed signals are valid. The verification process is specifically as follows: valid wheel speed signals are read during constant speed driving, and the deviation of each wheel speed signal from the other wheel speed signals is detected. If all the deviations exceed a set deviation threshold, it is determined that the wheel speed sensor signal corresponding to the wheel speed signal is invalid (i.e., the wheel speed signal is not an actual sampled wheel speed signal but an invalid wheel speed signal).

[0038] FIG. 3 is a structural schematic diagram of an independent and redundant wheel speed processing system using dual MCUs according to an embodiment of the present invention, and for the sake of explanation, only the parts relevant to the embodiment of the present invention are shown.

[0039] The independent and redundant wheel speed processing system includes 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.

[0040] The master MCU calculates the wheel speed signal of the corresponding wheel speed sensor according to the valid wheel speed pulse signal output from the wheel speed signal verification module.

[0041] The slave MCU calculates the speed signal and speed direction of the corresponding wheel speed sensor based on the valid wheel speed pulse signal output from the wheel speed signal verification module, and sends the calculated speed signal and speed direction of the wheel speed sensor to the master MCU. The master MCU verifies the wheel speed signal, and if the wheel speed signals calculated by the master MCU and the slave MCU are consistent, it determines that the master MCU is not faulty.

[0042] In the embodiment of the present invention, since there is a lot of information about the speed direction, even if a failure occurs in the master MCU, as long as the slave MCU is normal, the slave MCU can still process the valid wheel speed pulse signals output from the wheel speed signal processing unit and output the processed wheel speed pulse signals to the electrical control units that require them via the CAN interface.

[0043] The independent and redundant wheel speed processing system of the present invention has the following beneficial technical effects:

[0044] (1) Instead of using a highly integrated chip, four independent wheel speed signal processing units sample the wheel speed signals, thereby meeting the requirements for validity and synchronization of wheel speed signals from a functional safety perspective. The wheel speed signals are diagnosed using a software algorithm, eliminating the correlation interference of the four individually designed wheel speed sensor signals and satisfying the independence requirement. This provides a safety mechanism design that meets functional safety requirements and improves the timeliness of wheel speed signal fault diagnosis. After function degradation, fault information is sent to the HMI, and finally, fault information is displayed on the instrument panel to warn the driver and transition the system to 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 sampling circuit fails, the validity of the three wheel speed sensor signals can be guaranteed. Even if a single MCU fails, the validity of the four wheel speed signals can be guaranteed. This meets the functional safety and functional redundancy requirements of the brake system while reducing the cost of the electric control unit in the vehicle's brake system.

[0045] FIG. 4 is a flowchart of an independent and redundant wheel speed processing method according to an embodiment of the present invention, which specifically includes the following steps S1 to S4.

[0046] In step S1, the high-side voltage signals of the four wheel speed sensors and the output signals of the sampling circuits are sampled, and it is determined whether a high-side drive fault exists in the wheel speed sensors based on the high-side voltage signals, and whether a low-side drive fault exists in the sampling circuit based on the output signals of the sampling circuits.

[0047] In step S2, if a high-side drive failure and / or a low-side drive failure exists, it is determined that the corresponding wheel speed sensor has failed, and step S3 is executed for the wheel speed sensors that do not have a high-side drive failure or a low-side drive failure.

[0048] In step S3, it is detected whether the wheel speed information output from the wheel speed sensor is valid. If the detection result is YES, the process proceeds to step S4. If the detection result is NO, it is determined that the state and signal of the corresponding wheel speed sensor have failed.

[0049] In step S4, the MCU verifies the valid wheel speed information, and if an invalid wheel speed signal is detected, determines that a fault exists in the wheel speed sensor corresponding to the invalid wheel speed signal.

[0050] Although the present invention has been described above as an illustrative example, it goes without saying that the specific implementation of the present invention is not limited to the above-mentioned embodiments, and various insubstantial improvements made by adopting the methods, concepts and technical solutions of the present invention, or direct application of the concepts and technical solutions of the present invention to other situations without improvements, are all within the scope of protection of the present invention.

Claims

1. Four wheel speed sensors are provided on the four wheels, respectively; The four wheel speed sensors are connected to the MCU via four wheel speed signal processing units, respectively. The four wheel speed signal processing units diagnose drive abnormalities and wheel speed signal abnormalities of the four wheel speed sensors, respectively, and transmit the diagnosis results and the wheel speed signals output from the corresponding wheel speed sensors to the MCU.

2. The wheel speed signal processing unit includes a driving diagnostic module for diagnosing a driving abnormality of a corresponding wheel speed sensor, and the driving diagnostic module includes a high-side driving diagnostic sub-module and a low-side driving diagnostic sub-module; The high-side drive diagnostic sub-module diagnoses high-side drive failure of the wheel speed sensor based on the high-side voltage; The low-side driving diagnostic sub-module performs fault diagnosis on the output signal of the wheel speed sensor based on the sampling circuit; 2. The independent and redundant wheel speed processing system according to claim 1, wherein each wheel speed sensor is provided with an independent power supply circuit and sampling circuit, the power supply circuit being used to supply power to the wheel speed sensor, and the sampling circuit being used to sample the wheel speed sensor signal.

3. An ADC sampling circuit is provided on the high side of each wheel speed sensor to sample the ADC value of the voltage of the corresponding wheel speed sensor; 3. The independent redundant wheel speed processing system of claim 2, wherein the high side drive diagnosis is performed by comparing the operating voltage corresponding to the ADC value sampled by the ADC sampling circuit with a reference voltage value output from the MCU to detect whether the current operating voltage of the wheel speed sensor is within a valid operating voltage range, and if the operating voltage of the wheel speed sensor is within the valid operating voltage range, determining that the high side drive of the corresponding wheel speed sensor is normal.

4. The wheel speed signal processing unit includes a wheel speed diagnosis module for diagnosing an abnormality in the wheel speed signal; An ADC sampling circuit is provided in an interface to which the wheel speed pulse is input, and the ADC sampling circuit samples the wheel speed pulse signal output from the wheel speed sensor; 2. The independent redundant wheel speed processing system according to claim 1, wherein the wheel speed signal is diagnosed by diagnosing the amplitude of the wheel speed pulse signal sampled by the ADC sampling circuit, and determining that the wheel speed signal output from the wheel speed sensor is valid if the amplitude of the wheel speed pulse signal is within a set amplitude range.

5. The wheel speed signal verification module is integrated into the MCU.

2. The independent and redundant wheel speed processing system according to claim 1, wherein the wheel speed signal verification module receives valid wheel speed signals sent from the four wheel speed signal processing units and performs verification based on the valid wheel speed signals.

6. 6. The independent and redundant wheel speed processing system according to claim 5, wherein the valid wheel speed signals are verified by reading valid wheel speed signals during constant speed driving, detecting deviations of each wheel speed signal from other wheel speed signals, and determining that the wheel speed sensor signal corresponding to the wheel speed signal is invalid if all deviations exceed a preset deviation threshold.

7. It includes two MCUs, a master MCU and a slave MCU, The output terminals of the four wheel speed signal processing units are respectively connected to the master MCU and the slave MCU; 2. The independent and redundant wheel speed processing system according to claim 1, wherein the master MCU and the slave MCU respectively calculate the wheel speed signals of the corresponding wheel speed sensors based on the valid wheel speed pulse signals output from the wheel speed signal verification modules.

8. 8. The independent redundant wheel speed processing system according to claim 7, wherein the slave MCU calculates the wheel speed signal of the corresponding wheel speed sensor based on the valid wheel speed pulse signal and transmits it to the master MCU, and if the wheel speed signals calculated by the master MCU and the slave MCU are consistent, it is determined that the master MCU is not faulty.

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, comprising: Step S1: sampling the high-side voltage signals of the four wheel speed sensors and the output signals of the sampling circuits, and detecting whether a high-side drive fault exists in the wheel speed sensors based on the high-side voltage signals, and detecting whether a low-side drive fault exists in the sampling circuits based on the output signals of the sampling circuits; Step S2: if a high-side drive fault and / or a low-side drive fault exists, determining that the corresponding wheel speed sensor has failed, and executing step S3 for the wheel speed sensor that does not have a high-side drive fault and a low-side drive fault; Step S3: detecting whether the wheel speed information output from the wheel speed sensor is valid, and if the detection result is YES, proceeding to step S4; if the detection result is NO, determining that the state and signal of the corresponding wheel speed sensor are faulty; and (S4) the MCU verifies the valid wheel speed information, detects an invalid wheel speed signal, and determines that a fault exists in the wheel speed sensor corresponding to the invalid wheel speed signal.

Images