Steering system angle sensing method

Abstract

The application discloses a kind of steering system angle sensing method, solve the problem that single-sided SN bipolar magnet installation direction needs 0 ° magnetic field.Method includes setting magnetic angle sensor, the magnetic field angle of magnet on rotating element or driven gear is sensed and absolute angle value is output.Initialization records starting absolute angle, according to the relationship between current absolute angle and starting angle, calculate relative angle, and then judge rotating direction and number of turns.Combining relative angle, rotating direction and number of turns, the exact angle and direction of main rotating element or main gear are calculated.In addition, if rotating element is not 0 ° when system starts, the rotating information stored when last time is closed can be read, and offset compensation is carried out to correct the angle.This method does not need to consider the installation direction of magnet, and improves application flexibility.

Description

Technical Field

[0001] This invention relates to a steering system angle sensing method, and more particularly to a steering system angle sensing method that can convert absolute angles into relative angles, determine the direction of rotation and the cumulative number of rotations, and calculate the final angle between 0 and 360 degrees, or, based on the periodic definition of a generalized trigonometric function, not be limited to 360 degrees, but continuously maintain the cumulatively calculated steering angle. Background Technology

[0002] Steering angle sensors are widely used in vehicle steering systems to detect the steering angle of the car's steering wheel, enabling related systems (such as the body control module and electronic stability control system) to know the steering angle and then execute corresponding safety control strategies.

[0003] Specifically, the steering angle sensor utilizes a single-sided SN bipolar magnet embedded in at least one pinion. It senses the change in the magnetic field angle (ranging from 0° to 360°) during gear rotation and calculates the current steering wheel rotation angle based on the gear ratio between the main gear (steering column) and the two pinions. To ensure the initial steering angle of the steering wheel is 0° when the sensor is activated, it is crucial that the steering angle reading remains consistent after system startup. Therefore, the installation orientation of the single-sided SN bipolar magnet and its alignment with the gears are critical during sensor assembly. Besides ensuring the magnet's orientation is within the 0° magnetic field, the gear assembly must also ensure that the main gear's steering angle aligns with the steering wheel's steering angle. This assembly process significantly increases the difficulty of manufacturing the steering angle sensor and typically requires additional angle positioning tools and jigs to ensure installation accuracy, thus increasing production costs. To simplify the process and reduce errors during assembly, manufacturers of vehicle steering systems may choose to use more expensive angle sensors. These sensors have automatic zeroing correction capabilities and can handle the angle zeroing positioning problem entirely in hardware, but their development and production costs are also higher.

[0004] Therefore, with the increasing complexity of automotive electronic systems today, developing an economical and accurate angle sensing solution has become one of the important issues in the industry. Summary of the Invention

[0005] Therefore, the present invention mainly provides a steering system angle sensing method that does not require special calibration, does not require adjusting the installation direction of the single-sided SN bipolar magnet to 0 degrees during the production and assembly process, and can also ensure that the output angle of the steering element or driven gear is 0 degrees when it is in the corrected state, so as to provide an economical and accurate angle sensing solution.

[0006] This invention discloses a steering system angle sensing method for sensing the rotation of at least one rotating element in the steering system. Each rotating element has a magnet disposed on it. The steering system includes a main gear connected to a steering shaft; at least one driven gear meshing with the main gear; at least one magnet disposed on each driven gear; at least one magnetic angle sensor for sensing the angle of the magnetic field generated by the at least one magnet and outputting at least one absolute angle value; a processing unit; and a storage unit coupled to the processing unit, storing program code that instructs the processing unit to execute the steering system angle sensing method to sense the rotation of at least one rotating element or driven gear using at least one magnetic angle sensor. The steering system angle sensing method includes the following steps: recording at least one first set of any absolute angle values ​​between 0 and 360 degrees output by the at least one magnetic angle sensor after completing its initialization program. The system records at least one initial absolute angle; calculates at least one current relative angle value based on the relationship between at least one current absolute angle value measured by the at least one magnetic angle sensor and the at least one initial absolute angle value; determines the rotation direction of the at least one rotating element or the at least one driven gear based on the at least one current relative angle value and each of the at least one set of previous relative angle values; determines the number of rotations of the at least one rotating element or the at least one driven gear based on the positional changes of the at least one current relative angle value and each of the at least one set of previous relative angle values ​​relative to a plurality of default quadrants; and calculates and determines the actual rotation angle, direction, and number of rotations of the primary gear meshing with the at least one rotating element or the at least one driven gear based on at least one of the at least one current relative angle value, the rotation direction of the at least one rotating element or the at least one driven gear, and the number of rotations of the at least one rotating element or the at least one driven gear. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a steering angle sensing system according to an example of the present invention.

[0008] Figure 2 This is a schematic diagram of the steering angle sensing process in an example of the present invention.

[0009] Figure 3 This is a schematic diagram of the functional unit set of an example of the present invention.

[0010] Figure 4 This is a schematic diagram of a gear system according to an example of the present invention.

[0011] The reference numerals in the attached figures are explained as follows:

[0012] 10: Steering angle sensing system

[0013] 12: Rotating element

[0014] MG: Magnet

[0015] 14: Magnetic Angle Sensor

[0016] 16: Judgment Module

[0017] 160: Processing Unit

[0018] 162: Storage Unit

[0019] 20: Steering Angle Sensing Process

[0020] 200-212: Steps

[0021] 30: Functional Unit Set

[0022] 300: Initial absolute angle initialization unit

[0023] 302: Absolute angle to relative angle conversion unit

[0024] 304: Storage Unit

[0025] 306: Correction Unit

[0026] 308: Rotation Direction Determination Unit

[0027] 310: Rotation Count Determination Unit

[0028] 312: Calculation and judgment unit for actual rotation angle, direction, and number of revolutions

[0029] θ° abs Absolute angle value

[0030] θ° star_abs Starting absolute angle

[0031] ±θ° abs : Angle deviation value

[0032] θ° rel Relative angle value

[0033] GRD: Rotation Direction

[0034] ROT: Number of rotations

[0035] 40: Gear System

[0036] 42: Main gear

[0037] 44, 46: Driven gear Detailed Implementation

[0038] Certain terms are used in this specification and the claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and the claims do not distinguish components by differences in name, but by differences in function. The terms "comprising" and "including" used in this specification and the claims are open-ended and should be interpreted as "including but not limited to". "Substantially" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect. Furthermore, the term "coupled" here includes any direct and indirect, wired and wireless connection means.

[0039] To reduce the development or production cost of steering angle sensors, magnetic angle sensors based on the Tunnel Magnetoresistance (TMR) effect can be used. These sensors can output absolute angles from 0° to 360°, increasing or decreasing the angle according to the direction of rotation. After one full rotation (left or right), the absolute angle returns to 0°, and the angle sensing output cyclically increases or decreases again according to the direction of rotation. However, since TMR magnetic angle sensors only sense and output absolute angles, there is a problem with zeroing the angle during assembly production, and they cannot determine the direction and number of gear rotations. To address this, this invention proposes a steering system angle sensing method that effectively solves the problem of zeroing the angle during assembly production when the single-sided SN bipolar magnet must be installed in a 0° magnetic field. It converts the absolute angle into a relative angle and determines the direction and number of rotations to calculate the final steering angle of the steering system.

[0040] Please refer to Figure 1 , Figure 1This is a schematic diagram of a steering angle sensing system 10 according to an embodiment of the present invention. The steering angle sensing system 10 is used to sense the rotation of a rotating element 12. The rotating element 12 can be a gear or any rotatable component, and a magnet MG is disposed thereon. The steering angle sensing system 10 includes a magnetic angle sensor 14 and a determination module 16. The magnetic angle sensor 14 is preferably a sensor based on the tunneling magnetoresistance effect, used to sense the angle of the magnetic field generated by the magnet MG and output an absolute angle value. The determination module 16 includes a processing unit 160 and a storage unit 162. It can use the magnetic angle sensor 14 to sense the rotation of the rotating element 12, and the rotation of the rotating element 12 includes the rotation angle, the number of rotations, the rotation direction, etc. Specifically, the storage unit 162 can store program code 164, which can instruct the processing unit 160 to execute the steering angle sensing process 20 to convert the absolute angle value sensed by the magnetic angle sensor 14 into a relative angle value. At the same time, it can also determine the rotation direction and rotation angle of the rotating element 12 by using the absolute angle value and the relative angle value.

[0041] Please continue to refer to this. Figure 2 , Figure 2 This is a schematic diagram of the steering angle sensing process 20. The steering angle sensing process 20 includes the following steps:

[0042] Step 200: Begin.

[0043] Step 202: Record the first set of absolute angle values ​​between 0 and 360 degrees output by the magnetic angle sensor 14 after completing the initialization program as the starting absolute angle.

[0044] Step 204: Calculate the initial relative angle value based on the initial absolute angle obtained in step 202 using the relative angle conversion formula.

[0045] Step 206: Based on the absolute angle value obtained when the rotating element 12 rotates, which is converted into the current relative angle value and the initial relative angle value obtained in step 204, determine and obtain the rotation direction of the rotating element 12.

[0046] Step 208: Based on the rotation direction obtained in step 206 and the positional change of the current relative angle value relative to multiple default quadrants, determine and obtain the number of rotations of the rotating element 12.

[0047] Step 210: Calculate the actual rotation angle of the main gear based on the relative angle value of the rotating element 12 obtained in step 204 and the ratio between the main gear meshing with the rotating element 12.

[0048] Step 212: End.

[0049] According to the steering angle sensing process 20, the determination module 16 records any absolute angle value between 0 and 360 degrees output by the magnetic angle sensor 14 after completing the initialization procedure as the initial absolute angle (step 202), which serves as the basic reference angle. Next, in step 204, the determination module 16 calculates the current initial relative angle value based on the initial absolute angle value detected in step 202 using a relative angle conversion method. The initial relative angle value is the main angle parameter for calculating the rotation of the rotating element 12. Specifically, in this example, if the current absolute angle value is greater than or equal to the initial absolute angle value and less than or equal to 360 degrees, the steering angle sensing process 20 determines that the current relative angle value is equal to the current absolute angle value minus the initial absolute angle value; conversely, if the current absolute angle value is less than the initial absolute angle value, the steering angle sensing process 20 determines that the current relative angle value is equal to the current absolute angle value plus 360 degrees and then minus the initial absolute angle value. For example, if the first set of absolute angle values ​​output by the magnetic angle sensor 14 after completing the initialization process is 45°, then according to the steering angle sensing process 20, the judgment module 16 sets the initial absolute angle to 45°. Next, if the magnetic angle sensor 14 subsequently detects four absolute angle values ​​of 45°, 46°, 47°, and 48°, then according to step 204, the judgment module 16 determines the corresponding relative angle values ​​to be 0°, 1°, 2°, and 3°; conversely, if the magnetic angle sensor 14 subsequently detects four absolute angle values ​​of 45°, 44°, 43°, and 42°, then according to step 204, the judgment module 16 determines the corresponding relative angle values ​​to be 0°, 359°, 358°, and 357°.

[0050] Next, in step 206, the determination module 16 determines the rotation direction of the rotating element 12 based on the currently calculated relative angle value and the previous relative angle value. For example, in one instance, if the current relative angle value is the same as the previous relative angle value, the determination module 16 can determine whether the rotating element 12 is in a stationary state when the system starts up and has not rotated, or whether the rotating element 12 has completed one rotation from any direction and returned to the initial absolute angle state. According to the definition of generalized trigonometric functions, counterclockwise (left turn) is an angle increase, and clockwise (right turn) is an angle decrease. If the current relative angle value is greater than the previous relative angle value, the determination module 16 determines that the rotating element 12 is rotating in the counterclockwise (left turn) direction; conversely, if the current relative angle value is less than the previous relative angle value, the determination module 16 determines that the rotating element 12 is rotating in the clockwise (right turn) direction.

[0051] In another example, the judgment module 16 can perform different judgment procedures based on the previous rotation direction state result; it can be determined according to the four-quadrant division of generalized trigonometric functions, namely the first quadrant (angle value from 0 to 90 degrees), the second quadrant (angle value from 90 to 180 degrees), the third quadrant (angle value from 180 to 270 degrees), and the fourth quadrant (angle value from 270 to 360 degrees). For example, when the previous rotation direction state is stationary, the judgment module 16 first compares the current absolute angle value with the initial absolute angle value. If the two are equal, it is determined that the rotating element 12 remains stationary. However, if the current absolute angle value is greater than the initial absolute angle value, and the calculated relative angle value falls between 0 and 90 degrees, it is determined that the rotating element 12 is rotating in the direction of the first quadrant (e.g., to the left). Conversely, if the current absolute angle value is less than the initial absolute angle value, and the calculated relative angle value falls between 270 and 359 degrees, it is determined that the rotating element 12 is rotating in the direction of the fourth quadrant (e.g., to the right).

[0052] Conversely, when the current rotation direction is not stationary, the judgment module 16 employs different judgment logic. In this case, if the current absolute angle value equals the initial absolute angle value, it is determined that the rotating element 12 has returned to its starting point, i.e., the initial absolute angle. Otherwise, the judgment module 16 determines the current rotation direction based on the previous rotation direction. Furthermore, while the rotating element 12 continues to rotate, the judgment module 16 can compare the current relative angle value with the previous (previously) relative angle value to determine whether the rotation direction has changed. Specifically, if the current rotation direction is to the left, and the current relative angle value equals the previous relative angle value, it indicates that the rotation angle of the rotating element 12 has returned to its initial position at startup, i.e., the relative angle is 0. This means that the rotating element 12 may have completed a full leftward rotation, or it may have reversed direction midway through the leftward rotation. Finally, the judgment module 16 records the current rotation direction state as the basis for the next judgment. Similarly, if the previous rotation direction was to the right and the current relative angle value is equal to the previous relative angle value, the judgment module 16 can determine that the rotating element 12 may have completed a full rotation to the right, or may have reversed direction during the rotation to the right, and record the current rotation direction state as the basis for the next judgment.

[0053] The above examples take into account the previous rotation state and adopt different judgment criteria according to different situations, which can more accurately reflect the actual motion state of the rotating element 12, especially in the process of transition between stationary and moving, thus providing more accurate motion state information.

[0054] Next, in step 208, the determination module 16 determines the number of rotations of the rotating element 12 based on the current relative angle value and the positional changes of the previous relative angle value relative to multiple default quadrants. In this example, the default quadrants are defined based on the converted relative angle values, and may include the first quadrant (relative angle value from 0 to 90 degrees), the second quadrant (relative angle value from 90 to 180 degrees), the third quadrant (relative angle value from 180 to 270 degrees), and the fourth quadrant (relative angle value from 270 to 360 degrees). That is, the determination module 16 can obtain two different quadrant definition systems to track the rotation of the rotating element 12: the first is the absolute quadrant, defined based on the absolute angle value directly output by the TMR magnetic angle sensor 14; the second is the relative quadrant, defined based on the converted relative angle value. Both quadrant systems follow the four-quadrant division method of generalized trigonometric functions, extending left, right, up, and down to form four regions with the center point of the rotating element 12 as the origin. In a preferred embodiment, the determination module 16 continuously monitors changes in the relative angle value within these preset quadrants, thereby accurately calculating the number of rotations of the rotating element 12. This method not only accurately tracks rotation but also adapts to different installation conditions, providing reliable angle sensing results. Furthermore, in another embodiment, the number of rotations includes both left and right rotations, and the determination module 16 can clear both left and right rotation counts when the left rotation count equals the right rotation count.

[0055] In short, compared to other sensing methods, this invention uses a quadrant-based method to determine the number of rotations. This method effectively solves the misjudgment problem caused by the rotating element 12 reversing mid-rotation. Furthermore, in this example, the determination module 16 tracks the motion path of the rotating element 12 based on the quadrant definition of generalized trigonometric functions. When the rotating element 12 rotates left or right, its angular position sequentially passes through four quadrants. The determination module 16 continuously tracks and records the current quadrant position of the rotating element 12, using this information as motion path parameters.

[0056] Specifically, firstly, the judgment module 16 determines and selects the next rotation direction—whether to turn left or right—based on the current rotation direction and the comparison between the current relative / absolute angle and the previous set of relative / absolute angles. It also uses the absolute and relative angle values ​​to determine the quadrant position of the current angle and updates the quadrant status in real time. Simultaneously, the judgment module 16 records the traversed quadrant paths in the motion path parameters. Notably, when processing right rotation, the judgment module 16 subtracts 360 degrees from the relative angle value obtained and converted from the magnetic angle sensor 14, ensuring it falls within the range of -1 to -359 degrees. This processing method conforms to the definition of positive and negative angle values ​​in generalized trigonometric functions: counterclockwise (left turn) is positive, and clockwise (right turn) is negative.

[0057] When the judgment module 16 detects that the motion path parameter is equal to the path parameter for a complete rotation, it means that the rotating element 12 has completely passed through all four quadrants. At this time, the system will decide whether to accumulate the number of left rotations or right rotations based on the direction of rotation. In particular, when the number of left rotations and the number of right rotations are not zero and their values ​​are equal, it means that the rotating element 12 has returned to the relative zero-degree angle position at the initial start-up, indicating that the rotating element 12 has completely returned to center and there is no angular deviation.

[0058] The above-mentioned method of calculating the number of revolutions based on the relative limits of the rotating element 12 can not only accurately track the number of revolutions of the rotating element 12, but also correctly handle the case of reverse motion, providing a reliable and accurate steering angle monitoring solution.

[0059] Finally, in step 210, the judgment module 16 calculates the actual rotation angle of the main gear and determines the actual rotation direction and number of rotations of the main gear by taking the relative angle value, rotation direction, and number of rotations obtained from the rotating element 12 and comparing them with the ratio of the number of teeth between the main gear meshing with the rotating element 12. This calculation and judgment using comprehensive rotation information obtained from the rotating element 12 provides more complete motion state information of the steering system, including its exact rotation angle, direction, and number of rotations completed.

[0060] It is worth noting that the steering angle sensing process 20 in this example also includes a mechanism to correct and restore the angle when the steering element 12 is not in a straightened state (initial relative angle 0 degrees) when the system is started, even if the initial relative angle calculated in step 204 is 0 degrees. Specifically, when the steering system is started, the judgment module 16 reads the initial absolute angle and initial relative angle that have been written into the non-volatile storage device, representing that the steering element 12 is straightened and the angle is 0 degrees. It then compares these values ​​with the first set of initial absolute angle values ​​and the converted initial relative angles output by the magnetic angle sensor 14 after the initialization process is completed, and calculates the angle offset value for compensation to correct the rotation angle of the rotating element 12, thereby improving the sensing accuracy.

[0061] It should be noted that the steering angle sensing process 20 is used to illustrate the main concepts of the present invention, and those skilled in the art can make different modifications based on it, and are not limited thereto. For example, when the steering angle sensing process 20 is implemented as a software program, each step of the steering angle sensing process 20 or its derivative variations can be implemented with different functional units, and each functional unit can be regarded as a program set, thread or function, etc., and auxiliary units required to implement the steering angle sensing process 20 can be appropriately added, which should be well known to those skilled in the art. For example, please refer to Figure 3 , Figure 3 This is a schematic diagram of the functional unit set 30 of an embodiment of the present invention. The functional unit set 30 corresponds to a thread in program code 164 to implement the steering angle sensing process 20. The functional unit set 30 includes a starting absolute angle initialization unit 300, an absolute angle to relative angle conversion unit 302, a storage unit 304, a correction unit 306, a rotation direction determination unit 308, a rotation count determination unit 310, and an actual rotation angle, direction, and number of rotations calculation and determination unit 312; wherein, the storage unit 304 is used to store the data required to implement the steering angle sensing process 20. Furthermore, θ° abs This represents the absolute angle value measured by the magnetic angle sensor 14, θ°. star_abs Indicates the initial absolute angle, θ° rel The values ​​represent relative angles, GRD represents the direction of rotation, and ROT represents the number of rotations. Specifically, the initial absolute angle initialization unit 300 can execute step 202 to initialize the first set of absolute angle values ​​θ° output by the magnetic angle sensor 14 after completing the initialization procedure. abs Recorded as the initial absolute angle θ° star_abs The absolute angle to relative angle conversion unit 302 can execute step 204 to convert the current absolute angle value θ° of the magnetic angle sensor 14. abs Compared with the initial absolute angle value θ° star_abs The relationship between them, calculate the relative angle value θ° reland the relative angle value θ° rel Stored in storage unit 304. Rotation direction determination unit 308 can execute step 206 to determine the current relative angle value θ°. rel and the previous relative angle value θ° stored in storage unit 304 rel The rotation direction GRD of the rotating element 12 is determined by comparing the angles between the two values, and the determined rotation direction GRD is stored in the storage unit 304. The rotation count determination unit 310 can execute step 208 to determine the rotation direction GRD based on the current relative angle value θ°. rel and the previous relative angle value θ° stored in storage unit 304 rel The number of rotations (ROT) of the rotating element 12 is determined relative to the position changes in multiple default quadrants. The actual rotation angle, direction, and number of rotations calculation and determination unit 312 can execute step 210 to determine the relative angle value θ°. rel The system determines and calculates the actual rotational state (angle, direction, and number of rotations) of the main gear meshing with the rotating element 12 by measuring the rotation direction (GRD) and the number of rotations (ROT). Furthermore, the calibration unit 306 can output the initial absolute angle value θ° after the magnetic angle sensor 14 completes the initial calibration procedure when the main gear meshing with the rotating element 12 is visually aligned to 0 degrees and its direction and angle are both centered. star_abs and the converted relative angle value θ° rel The corrected angle value and the absolute angle sensed by the magnetic angle sensor 14 are retrieved from the storage unit 304 when the steering system is started again. At the same time, they are provided to the initial absolute angle initialization unit 300 to determine and compensate for the rotation angle when the angle and position of the rotating element 12 in the user's eyes are not in the rectified state (initial relative angle 0 degrees), thereby improving the sensing accuracy.

[0062] Functional unit set 30 represents a feasible architecture for implementing steering angle sensing process 20. Detailed operation and variations thereof can be found in the foregoing description of steering angle sensing process 20, and will not be repeated here. Furthermore, in functional unit set 30, the linking relationships between units can represent operations such as data transfer or function calls, and are not limited to signal linking methods; this should be a skill familiar to those skilled in the art.

[0063] On the other hand, regarding hardware implementation, the processing unit 160 of the judgment module 16 can be a microprocessor, a digital signal processor (DSP), or a microcontroller, while the storage unit 162 can be a read-only memory (ROM), random access memory (RAM), flash memory, or other types of memory devices. Program code 164 is stored in the storage unit 162. When the system starts, the processing unit 160 can read and execute program code 164 to implement the various functions of the steering angle sensing process 20. In another example, some computationally intensive or time-sensitive functions (such as angle calculation and direction determination) can be implemented using hardware circuits, while other more complex logical judgments can be handled by software programs. This hybrid implementation achieves a balance between performance and flexibility, ensuring both system real-time performance and good scalability. Regardless of the implementation method, the judgment module 16 must correctly acquire the signal or data sensed by the magnetic angle sensor 14, which can be achieved, for example, through standard communication protocols such as Serial Communication Interface (SCI), Serial Peripheral Interface (SPI), or Inter-Integrated Circuit (I2C).

[0064] Furthermore, as mentioned above, the rotating element 12 can be any rotatable element. The steering angle sensing system 10 of this invention uses a magnetic angle sensor 14 to sense the angle of the magnetic field generated by the magnet MG, and converts the obtained absolute angle value into a relative angle value to determine the rotation direction and number of rotations of the rotating element 12. Therefore, this invention not only solves the problem of misjudgment that may occur in traditional sensing methods during reverse motion, but also provides a more accurate capability for monitoring rotational state. It should be noted that the steering angle sensing system 10 is not only suitable for sensing the steering angle of a single rotating element 12, but can also be appropriately adjusted and applied to gear systems with multiple driven gears to calculate the steering angle of the main gear. In this application scenario, the steering angle sensing system needs to consider the transmission ratio between gears to accurately calculate the actual rotation of the main gear.

[0065] For example, please refer to Figure 4 , Figure 4This is a schematic diagram of a gear system 40 according to an embodiment of the present invention. The gear system 40 is used to implement a part of a steering system and includes a primary gear 42 and driven gears 44 and 46. The center of the primary gear 42 is connected to or driven by a steering shaft, which in turn is connected to or driven by a steering wheel or other steering mechanism, thus the primary gear 42 can rotate with the steering wheel or other steering mechanism. The driven gears 44 and 46 mesh with the primary gear 42, and their number of teeth is less than the number of teeth of the primary gear 42. Therefore, when the steering wheel is turned, the primary gear 42 will rotate accordingly, driving the driven gears 44 and 46 to rotate as well.

[0066] In the example, both driven gears 44 and 46 are equipped with magnets and their respective steering angle sensing systems (e.g., Figure 1 The steering angle sensing system 10 is used, and then a calculation module integrates the steering angle judgment results of the driven gears 44 and 46. In another example, the driven gears 44 and 46 may share or partially share the judgment module of the steering angle sensing system (such as...). Figure 1 (Judgment module 16). However, regardless of how the steering angle sensing system for the gear system 40 is implemented, it detects the rotation of the driven gears 44 and 46 and executes the steering angle sensing process 20 respectively to calculate the relative angle value, rotation direction, and number of rotations of the driven gears 44 and 46. Next, the steering angle sensing system for the gear system 40 should convert the steering angle of the driven gears 44 and 46 into the steering angle of the main gear 42 based on the tooth ratio between the driven gears 44 and 46 and the main gear 42. For example, assuming the main gear 42 has 60 teeth and the driven gears 44 and 46 have 20 teeth, the gear ratio is 3:1. This means that the main gear 42 will only rotate once for every three rotations of the driven gears 44 and 46. In this case, the steering angle sensing system for the gear system 40 should divide the relative angle value of the driven gears 44 and 46 by 3 to obtain the actual rotation angle of the main gear 42. Similarly, the number of rotations of driven gears 44 and 46 also needs to be divided by 3 to obtain the actual number of rotations of main gear 42.

[0067] Furthermore, in the gear system 40, since there are two driven gears 44 and 46, in this example, the steering angle results of driven gears 44 and 46 can be summed and then averaged to reduce errors. In another embodiment, one of the driven gears 44 and 46 can be used as a redundant design, that is, the steering angle sensing system determines the steering angle of the main gear 42 based only on the steering angle result of one of the driven gears 44 and 46, and the other steering angle result can be used for verification or as a backup in case of failure. Moreover, in the gear system 40, driven gears 44 and 46 are gears with the same number of teeth. However, this is not a limitation. The present invention can also use multiple driven gears with different numbers of teeth to determine the steering angle of the main gear, as long as they are appropriately converted according to the gear ratio. This should be deduced by those skilled in the art from the foregoing. Furthermore, in addition to using two driven gears 44 and 46, in other examples, a single driven gear or three or more driven gears can also be used to determine the steering angle of the main gear. Such derivative variations should be easily deduced by those skilled in the art with reference to the foregoing description, and will not be elaborated here.

[0068] In short, by cross-referencing data from at least one driven gear, the steering angle sensing system of this embodiment can more accurately calculate the steering angle of the main gear. This redundant design not only improves the reliability of the system but also ensures normal operation even if the sensor on one of the driven gears fails. Furthermore, this design provides greater configuration flexibility for the gear system, freeing the sensor's mounting location from being limited by the main gear itself, making it particularly suitable for situations where space is limited or where mounting the sensor on the main gear is inconvenient.

[0069] For example, the steering angle sensing system 10 of the present invention can also be applied to a vehicle's steering wheel angle sensing system. In this application scenario, the system not only needs to accurately sense the steering wheel angle, but also needs to consider the mechanical connection between the steering wheel and the steering mechanism to provide accurate steering information to the vehicle's electronic control system. Through the present invention, in the application of steering wheel angle sensing, a magnetic angle sensor is installed in the gear set of the steering mechanism. Since the steering wheel can typically rotate multiple times (e.g., it may require three to four rotations from the far left to the far right), the multi-rotation counting function of the steering angle sensing process 20 is particularly important. The system continuously tracks and accumulates the steering wheel angle, the number of rotations, and determines the direction of rotation to ensure accurate reflection of the actual position of the steering wheel. Furthermore, since the steering wheel system is closely related to other electronic control units in the vehicle (e.g., Electronic Stability Control (ESC), Anti-lock Braking System (ABS), etc.), the steering angle sensing process 20 needs to provide steering angle information in real time and accurately. In practical applications, the system converts the sensed steering angle value into a standard format and transmits it to the relevant control unit via a vehicle communication network (such as a CAN bus).

[0070] It's worth noting that when the vehicle starts, the initial position of the steering wheel may not be at the center. In this case, the angle correction function of the steering angle sensing process 20 can compensate. That is, the system automatically sets the current position as a reference point relative to zero degrees each time it starts, and continuously tracks its relative displacement as the steering wheel is turned. In this way, even when the steering wheel is not at the center, the system can still provide accurate steering angle information.

[0071] By applying this invention to steering wheel angle sensing, not only can accurate steering angle information be provided, but it can also support various advanced active safety systems and driver assistance functions in modern vehicles, providing an important foundation for driving safety.

[0072] As described above, the steering angle sensing system and process of this invention uses a magnetic angle sensor to sense the angle of the magnetic field generated by a magnet, converts the obtained absolute angle value into a relative angle value, and then determines the rotation direction of the rotating element and calculates the number of rotations. Therefore, this invention not only solves the problem of misjudgment that may occur in traditional sensing methods during reverse motion, but also provides a more accurate capability for monitoring rotational state. Furthermore, the steering angle sensing system and process of this invention employs a relative quadrant judgment mechanism. By dividing the rotational motion into four quadrants and continuously tracking the changes in angle within these quadrants, the system can accurately calculate the number of rotations. This method is particularly suitable for applications requiring multiple rotation counts, such as sensing the steering angle of a steering wheel. In addition, the steering angle sensing system and process of this invention also has an angle correction function, which can automatically compensate for angle offsets caused by different installation positions, significantly improving the practicality and reliability of the system.

[0073] In practical applications, the steering angle sensing system and process of this invention offer excellent adaptability and scalability. It can accurately sense steering angles in complex systems with at least one driven gear, such as those monitoring the steering angle of a vehicle's direction of travel. This broad application potential makes this invention particularly suitable for use in modern industrial automation systems and vehicle electronic control systems.

[0074] In summary, through magnetic sensing technology and calculation methods, this invention can realize a precise, reliable and practical rotation angle sensing system, which can be appropriately applied to fields such as industrial automation and vehicle control.

[0075] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention shall be covered by the present invention.

Claims

1. A steering system angle sensing method for sensing the rotation of at least one rotating element in the steering system, wherein each of the at least one rotating element is provided with a magnet, characterized in that, The steering system includes: The main gear is connected to the steering shaft; At least one driven gear meshes with the main gear; At least one magnet is disposed on each of the at least one driven gear; At least one magnetic angle sensor is used to sense the angle of the magnetic field generated by the at least one magnet and output at least one absolute angle value; Processing unit; and A storage unit, coupled to the processing unit, stores program code that instructs the processing unit to execute the steering system angle sensing method to sense the rotation of the at least one rotating element or the single or multiple driven gears using the at least one magnetic angle sensor. The steering system angle sensing method includes the following steps: Record at least one first group of any absolute angle value between 0 and 360 degrees output by the at least one magnetic angle sensor after the initialization procedure is completed as at least one initial absolute angle. Based on the relationship between at least one current absolute angle value measured by the at least one magnetic angle sensor and the at least one initial absolute angle value, calculate at least one current relative angle value; Based on the at least one current relative angle value and each of the at least one set of previous relative angle values, determine one or more rotational directions of the at least one rotating element or the at least one driven gear; Based on the positional changes of the at least one current relative angle value and each of at least one set of previous relative angle values ​​relative to a plurality of default quadrants, determine the number of rotations of the at least one rotating element or the at least one driven gear; and The actual rotation angle, direction, and number of rotations of the primary gear meshing with the at least one rotating element or the at least one driven gear are calculated and determined based on at least one of the at least one current relative angle value, the rotation direction of the at least one rotating element or the at least one driven gear, and the number of rotations of the at least one rotating element or the at least one driven gear.

2. The steering system angle sensing method as described in claim 1, characterized in that, The step of calculating the at least one current relative angle value based on the relationship between the at least one magnetic angle sensor, the at least one current absolute angle value, and the at least one initial absolute angle value includes: If the at least one current absolute angle value is greater than or equal to the at least one initial absolute angle value and less than or equal to 360 degrees, then the at least one current relative angle value is determined to be equal to the at least one current absolute angle value minus the at least one initial absolute angle value; and If the at least one current absolute angle value is less than the at least one initial absolute angle value, then the at least one current relative angle value is determined to be equal to the at least one current absolute angle value plus 360 degrees and then minus the at least one initial absolute angle value.

3. The steering system angle sensing method as described in claim 1, characterized in that, The step of determining the rotation direction of the at least one rotating element or the at least one driven gear based on the at least one current relative angle value and at least one set of previous relative angle values ​​is to determine the current rotation direction state of the at least one rotating element or the at least one driven gear based on the previous rotation direction state of the at least one rotating element or the at least one driven gear and the relationship between their respective current absolute angle values ​​and initial absolute angle values, and includes: If the at least one current relative angle value is the same as its respective previous relative angle value, it is determined that the at least one rotating element or the at least one driven gear is in a stationary state. If the at least one current relative angle value is greater than its respective previous relative angle value, then according to the definition of generalized trigonometric functions, it is determined whether the at least one rotating element or the at least one driven gear rotates in the first quadrant direction or counterclockwise; and If at least one current relative angle value is less than its respective previous relative angle value, according to the definition of generalized trigonometric functions, it is determined whether the at least one rotating element or the at least one driven gear rotates in the fourth quadrant direction or in the clockwise direction.

4. The steering system angle sensing method as described in claim 1, characterized in that, Determining the number of rotations of the at least one rotating element or the at least one driven gear based on the positional changes of the at least one current relative angle value and each of the at least one set of previous relative angle values ​​relative to the plurality of default quadrants, wherein the number of rotations includes the step of determining the number of rotations to the left and the number of rotations to the right, includes: Record the order of the at least one current relative angle value and each of the at least one set of previous relative angle values ​​relative to the plurality of default quadrants; When the at least one current relative angle value and each of at least one set of previous relative angle values ​​have sequentially passed through the plurality of preset quadrants, the number of rotations is accumulated; and When the number of left turns equals the number of right turns, reset the number of rotations and the number of right turns.

5. The steering system angle sensing method as described in claim 1, characterized in that, The plurality of preset quadrants include a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant. The range of the first quadrant is from 0 degrees to 90 degrees, the range of the second quadrant is from 90 degrees to 180 degrees, the range of the third quadrant is from 180 degrees to 270 degrees, and the range of the fourth quadrant is from 270 degrees to 360 degrees.

6. The steering system angle sensing method as described in claim 1, characterized in that, Also includes: Record at least one first group of any absolute angle value between 0 and 360 degrees and its respective converted initial relative angle value output by the at least one magnetic angle sensor after completing the initialization procedure, and compare it with at least one relative angle value converted from at least one absolute angle value currently sensed by the at least one magnetic angle sensor by at least one angle offset value. as well as The system reads the initial relative angle values ​​converted from at least one initial absolute angle value written in the storage device and at least one first set of absolute angle values ​​between 0 and 360 degrees output after the initialization process of at least one magnetic angle sensor. The system then performs angular offset compensation calculations on each of these values ​​to correct the rotation angle of the at least one rotating element or the at least one driven gear.

7. The steering system angle sensing method as described in claim 1, characterized in that, The at least one rotating element is at least one driven gear.

8. The steering system angle sensing system as described in claim 1, characterized in that, Determining the rotation of the main gear based on at least one current relative angle value, the rotation direction of the at least one driven gear, and the number of rotations of the at least one driven gear includes: Based on the gear ratio of the main gear to at least one driven gear, determine the rotational ratio of the at least one driven gear relative to the main gear; and Based on the rotation ratio, the at least one current relative angle value, the rotation direction of the at least one driven gear, and the number of rotations of the at least one driven gear are converted into the rotation angle, rotation direction, and number of rotations of the main gear.

9. The steering system angle sensing system as described in claim 8, characterized in that, The steering shaft is connected to the steering wheel.

10. The steering system angle sensing system as described in claim 9, characterized in that, The steering system angle sensing method further includes converting the rotation of the main gear into the steering angle of the steering wheel.

11. The steering system angle sensing system as described in claim 1, characterized in that, It also includes at least one redundant driven gear, at least one redundant magnet, and at least one redundant magnetic angle sensor, used to replace the faulty element in the event of a failure of one or more of the at least one driven gear, the at least one magnet, and the at least one magnetic angle sensor.

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