Corner signal safety redundancy measurement method with fault processing mechanism

Abstract

The invention provides a corner signal safety redundancy measurement method with a fault processing mechanism, and the method comprises the steps: forming a safety redundancy system through a plurality of corner signals obtained from a steering wheel; the multiple rotation angle signals are generated by a rotation angle sensor mechanical structure which is connected with a steering wheel and comprises a driving gear and at least three driven gears with different tooth numbers, and the generation method comprises the steps that the rotation angle sensor mechanical structure collects rotation angle signals of the driven gears through multiple Hall sensors arranged in the rotation angle sensor mechanical structure; the rotation angle of the driving gear connected with the steering wheel is independently calculated according to the rotation angle difference of any two driven gears, multi-channel independent steering wheel rotation angle signals are obtained, and multi-channel information sources capable of being verified in real time are formed, so that the accuracy of signals collected by a Hall sensor for obtaining steering wheel rotation angle data is guaranteed; according to the invention, multi-channel independent steering wheel angle signals can be formed, multi-channel information sources are verified in real time, and the accuracy of signal acquisition of the Hall sensor is ensured.

Description

Technical Field

[0001] This invention relates to the field of automotive steering control technology, and in particular to a method for measuring the safety redundancy of steering signals with a fault handling mechanism. Background Technology

[0002] Steering wheel sensors are a crucial component of automotive steering control systems. They detect the torque and angle of the steering wheel, providing steering data to the vehicle's electronic control unit (ECU) to obtain the vehicle's turning angle information. As the automotive industry continues to evolve towards intelligent technology, automakers and drivers are placing increasingly higher demands on vehicle handling and stability. In intelligent driving systems, the signals from steering wheel sensors directly impact path planning and decision-making; therefore, their reliability and accuracy are paramount.

[0003] Currently, significant progress has been made in the design of steering wheel sensors. Products from leading companies like Hella and Bosch primarily utilize technologies such as optical encoders, magnetic sensors, or the Hall effect. For example, a Hall effect-based automotive steering wheel angle sensor, as described in patent CN214875120, mainly consists of a drive wheel, driven wheels A and B, corresponding Hall effect sensing chips (mounted below the large and small gears respectively), and an MCU processor. The Hall effect sensing chip detects gear rotation and outputs a corresponding voltage signal to the processor. The processor receives the voltage signal and calculates the absolute steering angle of the steering wheel using a vernier algorithm. The structure is simple. These sensors provide basic steering angle measurement functions and are widely used in traditional vehicle steering systems. However, with the increasing prevalence of ADAS (Advanced Driver Assistance Systems) in the automotive field, its mandatory requirements for functional safety (ISO 26262) and signal redundancy have highlighted the limitations of traditional steering wheel sensor technology, primarily manifested in the following ways:

[0004] Traditional steering wheel angle sensors typically employ a single-stage gear coupling structure (one driving wheel and two driven wheels). The ratio between the rotation angle of the driving wheel and the steering wheel rotation angle is 1:1. The rotation angle of the driving wheel is derived from the angle difference and tooth count relationship between the two driven wheels. Most traditional sensors use a single-channel design. While this single-stage gear coupling structure adequately meets the accuracy requirements for current steering wheel angle measurements, it only provides a single steering wheel angle signal based on the angle difference between the two driven wheels, lacking hardware redundancy. In safety-critical scenarios such as high-speed driving and autonomous driving, if a channel malfunctions (e.g., a gear or Hall sensor fails, or electromagnetic interference occurs), providing an incorrect angle signal or failing to provide a backup angle signal, the system will lose its steering state perception capability, potentially leading to sudden failure of the steering control system and posing a serious safety hazard. Summary of the Invention

[0005] This invention proposes a safety redundancy measurement method for steering wheel angle signals with a fault handling mechanism. It can generate multi-channel independent steering wheel angle signals and perform real-time verification and timely fault diagnosis and processing of multiple information sources, ensuring the accuracy of the signals acquired by the Hall sensor and the accuracy of the steering wheel angle output signal. In scenarios with high safety requirements, such as autonomous driving, even if a Hall sensor fails or a mechanical malfunction causes an abnormal signal in that channel, the steering wheel sensor can still continuously output high-confidence measurement results through the fault handling mechanism.

[0006] The present invention adopts the following technical solution.

[0007] A safety redundancy measurement method for steering wheel angle signals with a fault handling mechanism is disclosed. The method uses multiple steering wheel angle signals acquired from the steering wheel to form a safety redundancy system. These multiple steering wheel angle signals are generated by a steering wheel angle sensor mechanical structure connected to the steering wheel, comprising one driving gear and at least three driven gears with different numbers of teeth. The generation method is as follows: the steering wheel angle sensor mechanical structure acquires the rotation angle signals of the driven gears through its built-in multi-channel Hall effect sensors; the rotation angle difference between any two driven gears is used to independently calculate the rotation angle of the driving gear connected to the steering wheel, thereby obtaining multi-channel independent steering wheel angle signals.

[0008] In the measurement method, the steering wheel system, based on the acquired multi-channel steering angle signals, continuously outputs high-confidence steering angle measurement results through a fault handling mechanism including multi-level fault-tolerant control. When some driven gear signals are detected to be abnormal, the steering wheel system reduces the weight of abnormal channels or removes them by comparing the dynamic relationship between the signal deviation between channels and the preset threshold in real time. When a fault occurs where only a single driven gear is available, the steering wheel system switches to emergency handling mode. By fusing the reference steering angle value in the historical measurement record of the steering angle signal and the relative steering angle change of the currently available channels, it continuously outputs an accurate absolute steering angle signal to ensure that normal steering control function can still be maintained under this fault condition.

[0009] The steering wheel is a car steering wheel. When the car is operating in a scenario with high safety requirements for autonomous driving, if a Hall sensor fails or a mechanical fault causes an abnormal signal in that channel, the steering wheel's angle sensor mechanical structure will continuously output a steering wheel angle measurement result with high confidence through a fault handling mechanism.

[0010] The steering wheel is a car steering wheel. In the mechanical structure of the angle sensor, there are three or more driven gears, and the number of teeth of each driven gear is different and coprime.

[0011] The mechanical structure of the angle sensor includes a driving gear S and driven gears A, B, and C, with the tooth profiles of the driving gear and driven gears being consistent.

[0012] The driving gear S is connected to each driven gear through a gear structure. The driving gear rotates coaxially with the steering wheel, and the rotation angle of the driving gear is the rotation angle data detected by the original sensor of the steering wheel.

[0013] The driving gear is connected to the rotation shaft of the steering wheel through an inlaid injection molding structure, and the driven gear meshes with the driving gear.

[0014] The driven gear integrates a flat, circular magnet, and a Hall sensor is positioned below the magnet. The Hall sensor is used to detect the rotation angle of the driven gear, and the detection data is sent to the MCU of the safety redundancy system for processing in the form of an electrical signal.

[0015] The method includes a dynamic measurement method for multi-channel absolute angle signals, and also includes a fault handling mechanism. This mechanism is based on the multi-channel angle measurement results and achieves redundant signal output under abnormal scenarios through real-time signal verification and multi-level fault-tolerant dynamic control.

[0016] Based on the multi-channel absolute steering angle signal dynamic measurement method, the safety redundancy system monitors the multi-channel steering wheel angle signal in real time at the software level. The MCU processor compares and analyzes the steering angle signal of each channel in real time with the theoretical rotation verification angle of the driven gear detected by the Hall sensor and the actual rotation angle. When there are slight deviations between the signals of each channel but none exceed the preset threshold and the signal detected by the Hall sensor is consistent with the theoretical value, the system uses a weighted algorithm to process the signal, that is, outputs the weighted average value of the multi-channel steering angle signal to reduce the impact of random errors.

[0017] The fault handling mechanism is as follows: when the deviation of a certain channel from other channels exceeds the preset threshold or the Hall sensor detection signal is inconsistent with the theoretical value, the system immediately reduces the credibility weight of the abnormal channel or removes the abnormal channel, selects a reliable channel as the output source, and ensures the accuracy and reliability of the output signal. The preset threshold of the multi-channel absolute angle signal dynamic measurement method is based on the comprehensive calibration of sensor accuracy and system safety tolerance.

[0018] Let the number of teeth of the driving gear be N. S The number of teeth of driven gears A, B, and C are N respectively. A N B N C And assume that the number of teeth is coprime and N A >N B >N C The Hall sensor is used to detect the rotation angle θ between driven gear A and driven gear B. A θ BThis involves capturing the current angular position of the driven gear. Assuming there's a possibility the driven gear may have already rotated multiple times during data detection, the main processing chip (MCU) records the number of rotations, n. A n B The formula for calculating the actual rotation angles of driven gears A and B is as follows:

[0019] φ A =θ A +360n A

[0020] φ B =θ B +360n B

[0021] Based on the fundamental relationship of gear meshing transmission, it can be seen that the rotation angle of the driving gear S and driven gears A and B is inversely proportional to the number of teeth. The specific calculation formula is as follows:

[0022]

[0023] Assuming both the driven gear and the driving gear start rotating from the zero position, and the MCU records the number of rotations from the zero position, it can be seen from the formula that the relative rotation angle of the driving gear can be obtained through a single driven gear, i.e., the relative rotation angle. The specific calculation formula is as follows:

[0024]

[0025] However, the relative rotation angle of the drive gear can only reflect the amount of rotation starting from zero. In reality, due to different installation or vehicle postures, the angle of the steering wheel at the start is not necessarily at zero. If the absolute angle of the drive gear is not calculated, the system cannot determine the true starting position of the steering wheel, resulting in a lack of reference for subsequent steering angle data, which in turn affects the accuracy of steering control.

[0026] The Hall sensor collects the rotation angle signals of driven gear A and driven gear B as periodic analog voltage signals. Since the number of teeth of the driven gears is different, the period of their signals is also different. When the steering wheel is turned, the phase difference of the periodic signals of driven gears A and B will gradually accumulate. When the steering wheel rotation reaches the measurement limit, the phase difference accumulates to a complete cycle.

[0027] The MCU obtains the periodic signal phase difference, i.e., the actual rotation angle difference φ, between driven gear A and driven gear B by detecting the voltage signal of the Hall sensor. AB The signal, specifically calculated using the following formula:

[0028]

[0029] Within the limit travel range of the steering wheel, the rotational angle difference φ between the two driven gears is measured. AB The absolute rotation angle φ of the driving gear is calculated. s1 The specific calculation formula is as follows:

[0030]

[0031] Similarly, the absolute rotation angle φ of the driving gear is calculated by combining the data of driven gear A and driven gear C, and driven gear B and driven gear C, respectively. s2 φ s3 The specific calculation formula is as follows:

[0032]

[0033] The theoretical rotation angle θ′ of the Hall sensor is calculated based on the absolute rotation angle of the drive gear. A , θ′ B , θ′ C And by the rotation angle θ detected by the Hall sensor A θ B θ C To determine if the sensor is faulty, a cross-verification process is performed. The specific calculation formula is as follows:

[0034]

[0035] The above method measures multiple active gear rotation angle signals based on multiple mutually verified information sources, thereby forming a multi-channel redundant rotation angle signal output;

[0036] If the sensor angle resolution is not higher than 0.1°, in order to ensure the accuracy of the final corner signal output and reduce the impact of random errors, the safety redundancy system sets a corner signal deviation threshold δ at the software level. The value of this threshold depends on the sensor angle resolution and system safety requirements.

[0037] When the deviation of the rotation angle signal of each channel is less than δ and the theoretical rotation angle verified by the Hall sensor is the same as the actual rotation angle, the MCU outputs the rotation angle signal using a weighted algorithm. The reliability of the rotation angle signal of each channel is judged by setting weights a, b, and c for each channel. The weight settings are based on the historical reliability and stability of each channel. The weight settings satisfy the condition that the sum of a, b, and c is 3. The specific calculation formula is as follows:

[0038]

[0039] in Calculate the angle deviation for each channel's corner signal. ω is the calibration deviation of the Hall sensor signal. iThe dynamic weighting adjustment coefficients are k1 and k2, which are adjustment coefficients and are linearly positively correlated with the set threshold. Through the above weighting process, the accuracy and reliability of the corner signal can be guaranteed.

[0040] If the threshold is set too high and each channel maintains a stable output, then set a=b=c=1 to distribute the weights evenly and reduce the amount of computation required by the processor.

[0041] When the deviation of the rotation angle signal of each channel is greater than δ or the Hall sensor rotation angle verification is incorrect, the MCU reduces the reliability of the faulty channel or forces a weight reduction, and selects a signal with higher consistency from the remaining reliable channels for output.

[0042] When a channel exceeds the set threshold three times consecutively, the corresponding weight is forcibly reduced and set to zero.

[0043] If the fault handling mechanism is based on the coordinated operation of multiple driven gears, the specific method is as follows: when the signal of a certain driven gear channel becomes unreliable due to mechanical structure or Hall sensor abnormality, if there are still multiple reliable driven gears, the safety redundancy system adjusts the output strategy, recalculates and outputs the rotation angle data of the driving gear based on the signals of the remaining driven gears; that is, the MCU processor recalculates the rotation angle of the driving gear based on the rotation angle difference between the remaining driven gears.

[0044] If the fault handling mechanism combines the reference value calculated by multiple channels during normal system operation with the calculation of the relative rotation angle of the driving gear obtained from a single driven gear, the specific method is as follows: When the steering angle sensor's mechanical structure only has a single driven gear providing relative rotation angle data, and the driving gear at the steering wheel can no longer output normal rotation angle data signals, the safety redundancy system uses the rotation angle reference value established by the MCU processor during normal operation, combined with the currently measured relative rotation angle, to calculate and output a complete absolute rotation angle signal. This allows the steering wheel sensor to maintain a stable steering signal output, improving the system's fault tolerance and robustness. That is, when only a single driven gear remains available, the steering wheel rotation angle data is calculated by combining the reference value calculated by multiple channels during normal system operation with the relative rotation angle of the driving gear obtained from a single driven gear. The specific formula is:

[0045]

[0046] φ S绝对 =φ S基准 +φ S相对

[0047] In the formula, it is assumed that the driven gear A is the only remaining reliable driven gear, and the number of rotations n′ A φ is the number of rotations of driven gear A recorded by the MCU from the moment driven gear B fails. s基准The absolute rotation angle of the driving gear is measured from the moment the driven gear B fails.

[0048] This invention designs a safe redundancy measurement method for steering angle signals with a fault handling mechanism. Based on a multi-driven wheel topology, it aims to acquire multiple information sources, achieve redundant output of steering angle signals, and improve the reliability and accuracy of the steering wheel sensor through real-time cross-verification of steering angle information. It has the following advantages:

[0049] 1. An absolute steering angle measurement method with cross-verification of multiple information sources. This invention designs a safe and redundant steering angle signal measurement method with a fault handling mechanism. Based on a redundant topology of a master-slave gear (three or more driven wheels with different numbers of teeth), it collects the rotation angle signals of the driven wheels through a designed multi-channel Hall sensor. The rotation angle of the master wheel is independently calculated from the difference in rotation angle between any two driven wheels, forming a multi-channel independent steering wheel angle signal. Furthermore, the multiple information sources are verified in real time to ensure the accuracy of the signals collected by the Hall sensors. In scenarios with high safety requirements, such as autonomous driving, even if a Hall sensor fails or a mechanical malfunction causes an abnormal signal in that channel, the steering wheel sensor can still continuously output high-confidence measurement results through the fault handling mechanism.

[0050] 2. Features dynamic processing and output of multi-channel absolute angle signals. This invention performs real-time monitoring of multi-channel angle signals at the software level. The MCU processor compares and analyzes the angle signals of each channel in real time with the theoretical and actual rotation angles of the driven wheel detected by the Hall sensor. When there are slight deviations between the signals of each channel but none exceed a preset threshold (based on a comprehensive calibration of sensor accuracy and system safety tolerance), and the Hall sensor detection signal is consistent with the theoretical value, the system uses a weighted algorithm to dynamically adjust the weight coefficients using verifiable Hall sensor signals and angle signals to reduce the impact of random errors and faults. When the deviation of a channel from other channels exceeds a preset threshold or the Hall sensor detection signal is inconsistent with the theoretical value, the system immediately reduces the credibility weight of the abnormal channel or removes the abnormal channel, selecting a reliable channel as the output source to ensure the accuracy and reliability of the output signal.

[0051] 3. Fault Handling Mechanism. Based on the aforementioned measurement method and redundant output design, this invention provides a method for measuring steering angle signals under abnormal scenarios and redundant output to ensure the stability of the steering wheel sensor's output signal under abnormal conditions. Compared to traditional steering wheel designs, this invention leverages the advantage of the coordinated operation of multiple driven wheels. When a driven wheel channel malfunctions due to mechanical or electrical problems, the system can quickly adjust its output strategy, recalculating and outputting the steering angle data of the driving wheel based on the signals from the remaining driven wheels. Especially when only a single driven wheel can provide a relative steering angle, traditional steering wheels can no longer output a normal steering angle signal. This invention uses the rotation angle reference value established by the MCU processor during normal operation, combined with the currently measured relative steering angle, to calculate and output a complete absolute steering angle signal. This enables the steering wheel sensor to maintain a stable steering angle signal output, improving the system's fault tolerance and robustness.

[0052] 4. The redundancy measurement method and fault handling mechanism described in this invention can be extended to four or more driven wheels to achieve a safer redundancy effect.

[0053] 5. This invention proposes a method to compensate for the deficiency that a single driven wheel cannot directly provide an absolute steering angle by using the steering wheel angle reference value before failure. This method is also applicable to traditional steering wheel sensors. Attached Figure Description

[0054] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0055] Appendix Figure 1 This is a schematic diagram of the structural principle of the present invention;

[0056] Appendix Figure 2 This is a schematic diagram of the structure of the present invention integrated into the steering wheel;

[0057] Appendix Figure 3 This is a schematic diagram of the principle of the present invention;

[0058] Appendix Figure 4 This is a flowchart illustrating the present invention;

[0059] Appendix Figure 5 This is a schematic diagram of the structural principle of the present invention for measuring and redundantly outputting corner signals under abnormal scenarios;

[0060] Appendix Figure 6 This is a schematic diagram of the principle of the present invention for measuring and redundantly outputting corner signals under abnormal scenarios. Detailed Implementation

[0061] As shown in the figure, a safe redundancy measurement method for steering angle signals with a fault handling mechanism is proposed. This method acquires multiple steering angle signals from the steering wheel and performs real-time fault diagnosis and processing to form a safe redundancy measurement method. The multiple steering angle signals are generated by a steering angle sensor mechanical structure connected to the steering wheel, containing one driving gear and multiple driven gears. The generation method is as follows: the steering angle sensor mechanical structure collects the rotation angle signals of the driven gears through its built-in multi-channel Hall effect sensors. The rotation angle of the driving gear connected to the steering wheel is independently calculated from the rotation angle difference between any two driven gears, obtaining multi-channel independent steering wheel steering angle signals. This forms a multi-channel information source that can be verified in real time. The reliability of the steering angle signals is verified in real time through the fault handling mechanism, and faults are handled promptly, continuously outputting high-confidence steering angle measurement results to ensure the accuracy of the steering angle signal output. A safety redundancy measurement method for steering wheel angle signals with a fault handling mechanism is disclosed. This method uses multiple steering wheel angle signals acquired from the steering wheel to form a safety redundancy system. These multiple steering wheel angle signals are generated by a steering wheel angle sensor mechanical structure connected to the steering wheel, comprising one driving gear and at least three driven gears with different numbers of teeth. The generation method involves the steering wheel angle sensor mechanical structure acquiring the rotation angle signals of the driven gears through its built-in multi-channel Hall effect sensors. The rotation angle difference between any two driven gears is used to independently calculate the rotation angle of the driving gear connected to the steering wheel, thereby obtaining multi-channel independent steering wheel angle signals.

[0062] In the measurement method, the steering wheel system, based on the acquired multi-channel steering angle signals, continuously outputs high-confidence steering angle measurement results through a fault handling mechanism including multi-level fault-tolerant control. When some driven gear signals are detected to be abnormal, the steering wheel system reduces the weight of abnormal channels or removes them by comparing the dynamic relationship between the signal deviation between channels and the preset threshold in real time. When a fault occurs where only a single driven gear is available, the steering wheel system switches to emergency handling mode. By fusing the reference steering angle value in the historical measurement record of the steering angle signal and the relative steering angle change of the currently available channels, it continuously outputs an accurate absolute steering angle signal to ensure that normal steering control function can still be maintained under this fault condition.

[0063] The reference angle value in the historical measurement record of the angle signal is the factory setting value of the vehicle.

[0064] The steering wheel is a car steering wheel. When the car is operating in a scenario with high safety requirements for autonomous driving, if a Hall sensor fails or a mechanical fault causes an abnormal signal in that channel, the steering wheel's angle sensor mechanical structure will continuously output a steering wheel angle measurement result with high confidence through a fault handling mechanism.

[0065] The steering wheel is a car steering wheel. In the mechanical structure of the angle sensor, there are three or more driven gears, and the number of teeth of each driven gear is different and coprime.

[0066] The mechanical structure of the angle sensor includes a driving gear S and driven gears A, B, and C, with the tooth profiles of the driving gear and driven gears being consistent.

[0067] The driving gear S is connected to each driven gear through a gear structure. The driving gear rotates coaxially with the steering wheel, and the rotation angle of the driving gear is the rotation angle data detected by the original sensor of the steering wheel.

[0068] The driving gear is connected to the rotation shaft of the steering wheel through an inlaid injection molding structure, and the driven gear meshes with the driving gear.

[0069] The driven gear integrates a flat, circular magnet, and a Hall sensor is positioned below the magnet. The Hall sensor is used to detect the rotation angle of the driven gear, and the detection data is sent to the MCU of the safety redundancy system for processing in the form of an electrical signal.

[0070] The method includes a dynamic measurement method for multi-channel absolute angle signals, and also includes a fault handling mechanism. This mechanism is based on the multi-channel angle measurement results and achieves redundant signal output under abnormal scenarios through real-time signal verification and multi-level fault-tolerant dynamic control.

[0071] In the dynamic measurement method of multi-channel absolute steering angle signal, the safety redundancy system monitors the multi-channel steering wheel angle signal in real time at the software level. The MCU processor compares and analyzes the steering angle signal of each channel in real time with the theoretical rotation verification angle of the driven gear detected by the Hall sensor and the actual rotation angle. When there are slight deviations between the signals of each channel but none exceed the preset threshold and the signal detected by the Hall sensor is consistent with the theoretical value, the system uses a weighted algorithm to process the signal, that is, outputs the weighted average value of the multi-channel steering angle signal to reduce the influence of random error.

[0072] The fault handling mechanism is as follows: when the deviation of a certain channel from other channels exceeds the preset threshold or the Hall sensor detection signal is inconsistent with the theoretical value, the system immediately reduces the credibility weight of the abnormal channel or removes the abnormal channel, selects a reliable channel as the output source, and ensures the accuracy and reliability of the output signal. The preset threshold of the multi-channel absolute angle signal dynamic measurement method is based on the comprehensive calibration of sensor accuracy and system safety tolerance.

[0073] Let the number of teeth of the driving gear be N. S The number of teeth of driven gears A, B, and C are N respectively. A N B N C And assume that the number of teeth is coprime and N A >N B >N C ,

[0074] If there are cases where the number of teeth is reversed, the parameters in the formula can be interchanged. If there are cases where the number of teeth is the same, the driven gear with the same number of teeth is equivalent to a single driven gear, which cannot meet the redundancy requirement.

[0075] Hall effect sensors are used to detect the rotation angle θ between driven gear A and driven gear B. A θ B This involves capturing the current angular position of the driven gear. Assuming there's a possibility the driven gear may have already rotated multiple times during data detection, the main processing chip (MCU) records the number of rotations, n. A n B The formula for calculating the actual rotation angles of driven gears A and B is as follows:

[0076] φ A =θ A +360n A

[0077] φ B =θ B +360n B

[0078] Based on the fundamental relationship of gear meshing transmission, it can be seen that the rotation angle of the driving gear S and driven gears A and B is inversely proportional to the number of teeth. The specific calculation formula is as follows: Assuming both the driven gear and the driving gear start rotating from the zero position, and the MCU records the number of rotations from the zero position, it can be seen from the formula that the relative rotation angle of the driving gear can be obtained through a single driven gear, i.e., the relative rotation angle. The specific calculation formula is as follows:

[0079]

[0080] However, the relative rotation angle of the drive gear can only reflect the amount of rotation starting from zero. In reality, due to different installation or vehicle postures, the angle of the steering wheel at the start is not necessarily at zero. If the absolute angle of the drive gear is not calculated, the system cannot determine the true starting position of the steering wheel, resulting in a lack of reference for subsequent steering angle data, which in turn affects the accuracy of steering control.

[0081] The Hall sensor collects the rotation angle signals of driven gear A and driven gear B as periodic analog voltage signals. Since the number of teeth of the driven gears is different, the period of their signals is also different. When the steering wheel is turned, the phase difference of the periodic signals of driven gears A and B will gradually accumulate. When the steering wheel rotation reaches the measurement limit, the phase difference accumulates to a complete cycle.

[0082] The MCU obtains the periodic signal phase difference, i.e., the actual rotation angle difference φ, between driven gear A and driven gear B by detecting the voltage signal of the Hall sensor. ABThe signal, specifically calculated using the following formula:

[0083]

[0084] Within the limit travel range of the steering wheel, the rotational angle difference φ between the two driven gears is measured. AB The absolute rotation angle φ of the driving gear is calculated. s1 The specific calculation formula is as follows:

[0085]

[0086] Similarly, the absolute rotation angle φ of the driving gear is calculated by combining the data of driven gear A and driven gear C, and driven gear B and driven gear C, respectively. s2 φ s3 The specific calculation formula is as follows:

[0087]

[0088] The theoretical rotation angle θ′ of the Hall sensor is calculated based on the absolute rotation angle of the drive gear. A , θ′ B , θ′ C And by the rotation angle θ detected by the Hall sensor A θ B θ C To determine if the sensor is faulty, a cross-verification process is performed. The specific calculation formula is as follows:

[0089]

[0090] The above method measures multiple active gear rotation angle signals based on multiple mutually verified information sources, thereby forming a multi-channel redundant rotation angle signal output;

[0091] If the sensor angle resolution is not higher than 0.1°, in order to ensure the accuracy of the final corner signal output and reduce the impact of random errors, the safety redundancy system sets a corner signal deviation threshold δ at the software level. The value of this threshold depends on the sensor angle resolution and system safety requirements.

[0092] When the deviation of the rotation angle signal of each channel is less than δ and the theoretical rotation angle verified by the Hall sensor is the same as the actual rotation angle, the MCU outputs the rotation angle signal using a weighted algorithm. The reliability of the rotation angle signal of each channel is judged by setting weights a, b, and c for each channel. The weight settings are based on the historical reliability and stability of each channel. The weight settings satisfy the condition that the sum of a, b, and c is 3. The specific calculation formula is as follows:

[0093]

[0094] in Calculate the angle deviation for each channel's corner signal. ω is the calibration deviation of the Hall sensor signal. i The dynamic weight adjustment coefficients are k1 and k2, which are adjustment coefficients and are linearly positively correlated with the threshold. Through the above weighting process, the accuracy and reliability of the corner signal can be guaranteed.

[0095] If the threshold is set too high and each channel maintains a stable output, then set a=b=c=1 to distribute the weights evenly and reduce the amount of computation required by the processor.

[0096] When the deviation of the rotation angle signal of each channel is greater than δ or the Hall sensor rotation angle θ is incorrectly verified, the MCU reduces the reliability of the faulty channel or forces a weight reduction, and selects a signal with higher consistency from the remaining reliable channels for output.

[0097] When a channel exceeds the limit three times consecutively, the corresponding weight is forcibly reduced and set to zero.

[0098] If the fault handling mechanism is based on the coordinated operation of multiple driven gears, the specific method is as follows: when the signal of a certain driven gear channel becomes unreliable due to mechanical structure or Hall sensor abnormality, if there are still multiple reliable driven gears, the safety redundancy system adjusts the output strategy, recalculates and outputs the rotation angle data of the driving gear based on the signals of the remaining driven gears; that is, the MCU processor recalculates the rotation angle of the driving gear based on the rotation angle difference between the remaining driven gears.

[0099] If the fault handling mechanism combines the reference value calculated by multiple channels during normal system operation with the calculation of the relative rotation angle of the driving gear obtained from a single driven gear, the specific method is as follows: When the steering angle sensor's mechanical structure only has a single driven gear providing relative rotation angle data, and the driving gear at the steering wheel can no longer output normal rotation angle data signals, the safety redundancy system uses the rotation angle reference value established by the MCU processor during normal operation, combined with the currently measured relative rotation angle, to calculate and output a complete absolute rotation angle signal. This allows the steering wheel sensor to maintain a stable steering signal output, improving the system's fault tolerance and robustness. That is, when only a single driven gear remains available, the steering wheel rotation angle data is calculated by combining the reference value calculated by multiple channels during normal system operation with the relative rotation angle of the driving gear obtained from a single driven gear. The specific formula is:

[0100]

[0101] φ S绝对 =φ S基准 +φ S相对

[0102] In the formula, it is assumed that the driven gear A is the only remaining reliable driven gear, and the number of rotations n′A φ is the number of rotations of driven gear A recorded by the MCU from the moment driven gear B fails. s基准 The absolute rotation angle of the driving gear is measured from the moment the driven gear B fails.

[0103] This example proposes a safe redundancy measurement method for steering angle signals with a fault handling mechanism. The aim is to acquire multiple information sources based on a multi-driven wheel topology, realize redundant measurement of steering angle signals, and verify steering angle information in real time through a fault handling mechanism, thereby improving the reliability and accuracy of steering wheel sensors.

[0104] This example uses a three-driven wheel (driven gear) as a detailed illustration. This method can be extended to four or more driven wheels to create more measurement channels, obtain more angle signals from these channels, and achieve a safer redundancy effect. The mechanical structure of the angle sensor designed in this invention includes one driving wheel (driving gear) S and three driven wheels A, B, and C. The driving wheel S is connected to each driven wheel via a gear structure and rotates coaxially with the steering wheel; therefore, the rotation angle of the driving wheel is the rotation angle of the steering wheel. The driving wheel engages with the steering wheel sensor through injection molding. The driven wheels mesh with the driving wheel via gears and are integrated into a flat, circular magnet. A Hall sensor is positioned below the magnet to detect the rotation angle of the driven wheels and send it to the MCU for processing in the form of an electrical signal.

[0105] To meet mechanical design requirements and ensure calculation consistency, the tooth profiles of the driving and driven gears must be identical. The number of teeth on the driving gear is specified as N. S The number of teeth of driven gears A, B, and C are N respectively. A N B N C And assume that the number of teeth is coprime and N A >N B >N C If there are cases where the number of teeth is reversed, the parameters in the formula can be interchanged. If there are cases where the number of teeth is the same, the driven gear with the same number of teeth is equivalent to a single driven gear, which cannot meet the redundancy requirement.

[0106] This example can be used to modify the traditional steering wheel angle sensor structure. The traditional steering wheel angle sensor structure uses a single-stage gear coupling structure (one driving wheel and two driven wheels). The ratio between the rotation angle of the driving wheel and the steering wheel rotation angle is 1:1. The rotation angle of the driving wheel needs to be obtained from the angle difference and tooth count relationship between the two driven wheels. The specific calculation formula is as follows:

[0107]

[0108] In the traditional steering wheel angle sensor structure, φ sφ is the rotation angle of the driving wheel. AB The difference in rotation angle between the two driven wheels is determined by a Hall sensor, N. S N A N B These represent the number of teeth on the driving gear, the number of teeth on driven gear A, and the number of teeth on driven gear B, respectively (assuming N). A Greater than N B If N A Less than N B Then the formula parameters need to be swapped. If N A equals N B The function of two driven wheels is equivalent to that of a single driven wheel.

Claims

1. A method for measuring the safety redundancy of corner signals with a fault handling mechanism, characterized in that: The measurement method uses multiple steering angle signals acquired from the steering wheel to form a safety redundancy system. These multiple steering angle signals are generated by a steering angle sensor mechanical structure connected to the steering wheel, which includes a driving gear and at least three driven gears with different numbers of teeth. The generation method is as follows: the steering angle sensor mechanical structure collects the rotation angle signals of the driven gears through its built-in multi-channel Hall sensors, and independently calculates the rotation angle of the driving gear connected to the steering wheel from the rotation angle difference between any two driven gears, thereby obtaining multi-channel independent steering wheel steering angle signals. In the measurement method, the steering wheel system, based on the acquired multi-channel steering angle signals, continuously outputs high-confidence steering wheel angle measurement results through a fault handling mechanism including multi-level fault-tolerant control. When some driven gear signals are detected to be abnormal, the steering wheel system reduces the weight of abnormal channels or removes abnormal channels by comparing the dynamic relationship between the signal deviation between channels and the preset threshold in real time. When a fault occurs where only a single driven gear is available, the steering wheel system switches to emergency processing mode, continuously outputting accurate absolute steering wheel angle signals by fusing the reference steering angle value in the historical measurement record of the steering angle signal and the relative steering angle change of the currently available channels.

2. The method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 1, characterized in that: The steering wheel is a car steering wheel. When the car is operating in a scenario with high safety requirements for autonomous driving, if a Hall sensor fails or a mechanical fault causes an abnormal signal in that channel, the steering wheel's angle sensor mechanical structure will continuously output a steering wheel angle measurement result with high confidence through a fault handling mechanism.

3. The method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 1, characterized in that: The steering wheel is a car steering wheel. In the mechanical structure of the angle sensor, there are three or more driven gears, and the number of teeth of each driven gear is different and coprime.

4. The method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 3, characterized in that: The mechanical structure of the angle sensor includes a driving gear S and driven gears A, B, and C, with the tooth profiles of the driving gear and driven gears being consistent. The driving gear S is connected to each driven gear through a gear structure. The driving gear rotates coaxially with the steering wheel, and the rotation angle of the driving gear is the rotation angle data detected by the original sensor of the steering wheel. The drive gear is connected to the rotation shaft of the steering wheel, and the driven gear meshes with the drive gear. The driven gear integrates a flat circular magnet, and a Hall sensor is arranged below the magnet. The Hall sensor is used to detect the rotation angle of the driven gear, and the detection data is sent to the MCU of the safety redundancy system for processing in the form of an electrical signal.

5. The method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 3, characterized in that: The method includes a dynamic measurement method for multi-channel absolute angle signals, and also includes a fault handling mechanism. This mechanism is based on the multi-channel angle measurement results and achieves redundant signal output under abnormal scenarios through real-time signal verification and multi-level fault-tolerant dynamic control.

6. The method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 5, characterized in that: Based on the multi-channel absolute steering angle signal dynamic measurement method, the safety redundancy system monitors the multi-channel steering wheel angle signal in real time at the software level. The MCU processor compares and analyzes the steering angle signal of each channel in real time with the theoretical rotation verification angle of the driven gear detected by the Hall sensor and the actual rotation angle. When there are slight deviations between the signals of each channel but none exceed the preset threshold and the signal detected by the Hall sensor is consistent with the theoretical value, the system uses a weighted algorithm to process the signal, that is, outputs the weighted average value of the multi-channel steering angle signal to reduce the impact of random errors. The fault handling mechanism is as follows: when the deviation of a certain channel from other channels exceeds the preset threshold or the Hall sensor detection signal is inconsistent with the theoretical value, the system immediately reduces the credibility weight of the abnormal channel or removes the abnormal channel, selects a reliable channel as the output source, and ensures the accuracy and reliability of the output signal. The preset threshold of the multi-channel absolute angle signal dynamic measurement method is based on the comprehensive calibration of sensor accuracy and system safety tolerance.

7. A method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 6, characterized in that: Let the number of teeth of the driving gear be N. S The number of teeth of driven gears A, B, and C are N respectively. A N B N C And assume that the number of teeth is coprime and N A >N B >N C The Hall sensor is used to detect the rotation angle θ between driven gear A and driven gear B. A ,θ B This involves capturing the current angular position of the driven gear. Assuming there's a possibility the driven gear may have already rotated multiple times during data detection, the main processing chip (MCU) records the number of rotations, n. A n B The formula for calculating the actual rotation angle of driven gears A and B is: φ A =θ A +360n A f B =θ B +360n B Based on the fundamental relationship of gear meshing transmission, it can be seen that the rotation angle of the driving gear S and driven gears A and B is inversely proportional to the number of teeth. The specific calculation formula is as follows: Assuming both the driven gear and the driving gear start rotating from the zero position, and the MCU records the number of rotations from the zero position, it can be seen from the formula that the relative rotation angle of the driving gear can be obtained through a single driven gear, i.e., the relative rotation angle. The specific calculation formula is as follows: The Hall sensor collects the rotation angle signals of driven gear A and driven gear B as periodic analog voltage signals. Since the number of teeth of the driven gears is different, the period of their signals is also different. When the steering wheel is turned, the phase difference of the periodic signals of driven gears A and B will gradually accumulate. When the steering wheel rotation reaches the measurement limit, the phase difference accumulates to a complete cycle. The MCU obtains the periodic signal phase difference, i.e., the actual rotation angle difference φ, between driven gear A and driven gear B by detecting the voltage signal of the Hall sensor. AB The signal, specifically calculated using the following formula: Within the limit travel range of the steering wheel, the rotational angle difference φ between the two driven gears is measured. AB The absolute rotation angle φ of the driving gear is calculated. s1 The specific calculation formula is as follows: The absolute rotation angle φ of the driving gear is calculated by combining the data of driven gear A and driven gear C, and driven gear B and driven gear C respectively. s2 φ s3 The specific calculation formula is as follows: The theoretical rotation angle θ′ of the Hall sensor is calculated based on the absolute rotation angle of the drive gear. A , θ′ B , θ′ C And by the rotation angle θ detected by the Hall sensor A ,θ B ,θ C To determine if the sensor is faulty, a cross-verification process is performed. The specific calculation formula is as follows: The above method measures multiple active gear rotation angle signals based on multiple mutually verified information sources, thereby forming a multi-channel redundant rotation angle signal output.

8. A method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 7, characterized in that: If the sensor angle resolution is not higher than 0.1°, in order to ensure the accuracy of the final corner signal output and reduce the impact of random errors, the safety redundancy system sets a corner signal deviation threshold δ at the software level. The value of this threshold depends on the sensor angle resolution and system safety requirements. When the deviation of the rotation angle signal of each channel is less than δ and the theoretical rotation angle verified by the Hall sensor is the same as the actual rotation angle, the MCU outputs the rotation angle signal using a weighted algorithm. The reliability of the rotation angle signal of each channel is judged by setting weights a, b, and c for each channel. The weight settings are based on the historical reliability and stability of each channel. The weight settings satisfy the condition that the sum of a, b, and c is 3. The specific calculation formula is as follows: in Calculate the angle deviation for each channel's corner signal. ω is the calibration deviation of the Hall sensor signal. i The dynamic weighting adjustment coefficients are k1 and k2, which are adjustment coefficients and are linearly positively correlated with the set threshold. Through the above weighting process, the accuracy and reliability of the corner signal can be guaranteed. If the threshold is set too high and each channel maintains a stable output, then set a=b=c=1 to distribute the weights evenly and reduce the amount of computation required by the processor. When the deviation of the rotation angle signal of each channel is greater than δ or the Hall sensor rotation angle verification is incorrect, the MCU reduces the reliability of the faulty channel or forces a weight reduction, and selects a signal with higher consistency from the remaining reliable channels for output. When a channel exceeds the set threshold three times consecutively, the corresponding weight is forcibly reduced and set to zero.

9. A method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 7, characterized in that: If the fault handling mechanism is based on the coordinated operation of multiple driven gears, the specific method is as follows: when the signal of a certain driven gear channel becomes unreliable due to mechanical structure or Hall sensor abnormality, if there are still multiple reliable driven gears, the safety redundancy system adjusts the output strategy, recalculates and outputs the rotation angle data of the driving gear based on the signals of the remaining driven gears; that is, the MCU processor recalculates the rotation angle of the driving gear based on the rotation angle difference between the remaining driven gears.

10. A method for measuring the safety redundancy of corner signals with a fault handling mechanism according to claim 7, characterized in that: If the fault handling mechanism combines the reference value calculated by multiple channels during normal system operation with the calculation of the relative rotation angle of the driving gear obtained from a single driven gear, the specific method is as follows: When the steering angle sensor's mechanical structure only has a single driven gear providing relative rotation angle data, and the driving gear at the steering wheel can no longer output normal rotation angle data signals, the safety redundancy system uses the rotation angle reference value established by the MCU processor during normal operation, combined with the currently measured relative rotation angle, to calculate and output a complete absolute rotation angle signal. This allows the steering wheel sensor to maintain a stable steering signal output, improving the system's fault tolerance and robustness. That is, when only a single driven gear remains available, the steering wheel rotation angle data is calculated by combining the reference value calculated by multiple channels during normal system operation with the relative rotation angle of the driving gear obtained from a single driven gear. The specific formula is: f S绝对 =φ S基准 +φ S相对 In the formula, it is assumed that the driven gear A is the only remaining reliable driven gear, and the number of rotations n′ A φ is the number of rotations of driven gear A recorded by the MCU from the moment driven gear B fails. s基准 The absolute rotation angle of the driving gear is measured from the moment the driven gear B fails.

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