An absolute value encoding method, system and program product for a magneto-optical encoder
By integrating a magnetic absolute encoder and an optical incremental encoder, and fusing absolute position values, the problems of poor anti-interference capability of magnetic encoders and complex manufacturing process of optical encoders are solved. Stable and accurate absolute position measurement is achieved in complex environments, improving system reliability and mean time between failures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TITANIUM TIGER ROBOT TECH (SHANGHAI) CO LTD
- Filing Date
- 2026-06-15
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, magnetic encoders have poor anti-interference capabilities and are easily affected by surrounding magnetic fields, resulting in reduced testing accuracy. On the other hand, optical encoders have complex manufacturing processes and are prone to failure in dusty environments, making it impossible to reliably obtain the absolute position of the movement of mechanical parts.
The absolute value encoding method of the optical-magnetic encoder is adopted, which integrates the magnetic absolute encoder and the optical incremental encoder, and fuses the absolute position values. The absolute position measurement and strong environmental adaptability of the magnetic absolute encoder are used for coarse positioning, and the high resolution of the optical incremental encoder is combined for precise positioning, outputting stable and accurate absolute position information.
It achieves stable and accurate output of absolute position information in complex environments, reduces costs, and seamlessly switches to magnetic absolute position value output when a single sensor fails, improving system reliability and mean time between failures.
Smart Images
Figure CN122384876A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of encoder technology, and in particular to an absolute value encoding method, system and program product for an optical-magnetic encoder. Background Technology
[0002] An encoder is a sensor used to measure the rotation or displacement of machinery. It can measure information such as the displacement position or velocity of mechanical parts during rotation or linear motion and convert it into a series of electrical signals.
[0003] Magnetic encoders or optical encoders can generally be used to detect and provide feedback on the position of mechanical components, accurately capturing real-time position information during mechanical motion. This provides reliable data support for the subsequent adjustment and control of the control system, ensuring the accuracy and stability of mechanical motion.
[0004] Understandably, encoders can be categorized into incremental encoders and absolute encoders based on their measurement mode. Incremental encoders primarily measure the relative displacement of mechanical components and require a fixed reference point to determine their absolute position. Absolute encoders, on the other hand, directly measure the absolute position without needing a fixed reference point.
[0005] Currently, single magnetic encoders or optical encoders are commonly used in the market to measure absolute position values. However, during production and use, magnetic encoders have poor anti-interference capabilities and are easily affected by surrounding magnetic fields, which can lead to reduced testing accuracy. Optical encoders, on the other hand, require two code tracks to output absolute position values, have a complex manufacturing process, and are prone to failure in dusty environments. Summary of the Invention
[0006] This application provides an absolute value encoding method, system, and program product for an optical-magnetic encoder to solve problems such as the inability to reliably obtain the accurate absolute position of mechanical parts.
[0007] Firstly, an absolute value encoding method for an optical-magnetic encoder is provided, which is applied to an encoder system, including an optical incremental encoder and a magnetic absolute value encoder. The methods include: When both the magnetic absolute encoder and the optical incremental encoder are in a non-faulty state, a fused absolute position value is obtained based on the magnetic absolute position value of the magnetic absolute encoder and the optical incremental value of the optical incremental encoder. The fused absolute position value is used as the output absolute position value of the encoder system. The magnetic absolute position value of the magnetic absolute encoder is used to determine the optical reference position of the optical incremental encoder. The magnetic absolute position value has a first precision, and the fused absolute position value has a second precision, which is higher than the first precision.
[0008] In one possible implementation of the first aspect, the method further includes: When the optical incremental encoder is in a faulty state and the magnetic absolute encoder is in a non-faulty state, the magnetic absolute position value is used as the output absolute position value.
[0009] Understandably, optical encoders generally have higher accuracy than magnetic encoders. After obtaining the magnetic absolute position value of a magnetic absolute encoder, the optical reference position value of an optical incremental encoder can be obtained. Adding the optical reference position value to the optical increment value yields a highly accurate fused absolute position value. In this way, a high-accuracy output absolute position value can be obtained without the more complex manufacturing process of an optical absolute encoder, thus reducing costs. Furthermore, the absolute position value of a magnetic absolute encoder is only used for reference positioning, allowing it to adapt to a wider range of environments.
[0010] Furthermore, by integrating the magnetic absolute encoder and the optical incremental encoder into one unit, the advantages of the two encoders can be complemented. The magnetic absolute encoder can be used for coarse positioning and safety assurance by measuring the absolute position and having strong environmental adaptability, while the optical incremental encoder can be used for precise positioning by having extremely high resolution. Finally, the two signals are fused to output a stable, accurate and reliable absolute position information.
[0011] In one possible implementation of the first aspect, the optical incremental encoder being in a non-faulty state includes: each photosensitive element in the optical incremental encoder being in a non-faulty state. The magnetic absolute encoder being in a non-fault state includes: the magnetic absolute encoder having a first preset number of magnetic sensitive elements in a non-fault state, the first preset number being the minimum number capable of completing absolute position decoding.
[0012] In one possible implementation of the first aspect, the optical incremental encoder is determined to be in a non-faulty state by: Acquire the raw signals currently output by each photosensitive element of the optical incremental encoder; Based on the original signals of each photosensitive element and the pre-stored optical encoding reference characteristic parameter values, the actual optical encoding characteristic parameter values of each photosensitive element used for fault diagnosis are determined. Among them, the optical encoding reference characteristic parameter values include: optical bias reference value and optical amplitude reference value; the actual optical encoding characteristic parameter values include: normalized amplitude deviation, residual bias amount and normalized instantaneous radius calculated after the original signals of each photosensitive element have undergone debiasing and amplitude normalization processing.
[0013] When the actual characteristic parameter values of the optical encoder all meet the evaluation conditions for the optical encoder characteristic parameters corresponding to a non-fault state, it is determined that each photosensitive element in the photoelectric encoder is in a non-fault state. The evaluation conditions for the optical encoder characteristic parameters include: normalized amplitude deviation evaluation condition, residual DC offset evaluation condition, Lissajous figure roundness evaluation condition, and channel gain consistency evaluation condition. In one possible implementation of the first aspect, the non-fault state of the magnetic sensitive element in the magnetic absolute encoder is determined by the following method: Acquire the raw signals of the current output of each magnetic sensitive element of the magnetic absolute encoder; Based on the original signals of each magnetic sensitive element and the pre-stored magnetic coding reference characteristic parameter values, the actual magnetic coding characteristic parameter values of each magnetic sensitive element used for fault diagnosis are determined. Among them, the magnetic coding reference characteristic parameter values include: magnetic bias reference value and magnetic amplitude reference value; the actual magnetic coding characteristic parameter values include: normalized amplitude deviation, residual bias amount and normalized instantaneous radius calculated after the original signals of each magnetic sensitive element have been debiased and amplitude normalized.
[0014] If the actual characteristic parameter values of the magnetic encoder all meet the evaluation conditions of the magnetic encoder characteristic parameters corresponding to the non-fault state, it is determined that each photosensitive element in the magnetic encoder is in a non-fault state. The evaluation conditions of the magnetic encoder characteristic parameters include: normalized amplitude deviation evaluation condition, residual DC offset evaluation condition, Lissajous figure roundness evaluation condition, and channel gain consistency evaluation condition.
[0015] In one possible implementation of the first aspect, the magnetic absolute encoder includes 12 magnetic sensitive elements and 14 pairs of non-uniform pole pitch magnets. The 12 magnetic sensitive elements are uniformly arranged directly above the magnets, covering a complete mechanical circumference. The 14 pairs of non-uniform pole pitch magnets include one first characteristic pole pair and 13 second characteristic pole pairs. The circumferential dividing angles of the 14 pole pairs along the circumference are 48°, 72°, 96°, 120°, 144°, 168°, 192°, 216°, 240°, 264°, 288°, 312°, 336°, and 360°, respectively. The magnetic absolute position value of the magnetic absolute encoder is obtained in the following manner: Acquire the calibrated magnetic encoder signal corresponding to the non-faulty magnetic sensor among the various magnetic sensor elements of the magnetic absolute encoder; Based on the current calibrated magnetic encoder signal corresponding to the magnetic sensor that is in a non-faulty state among the various magnetic sensor elements, a multi-dimensional measurement vector is obtained. The coarse absolute position of the magnetic absolute encoder is obtained by matching the multidimensional measurement vector with a pre-stored mechanical angle lookup table. The magnetic pole pair where each magnetic sensitive element is located is determined based on the coarse absolute position of the magnetic encoder. Based on the magnetic coding signals corresponding to the two adjacent magnetic sensitive elements located within the second characteristic magnetic pole, the fine electrical angle within the period of the second characteristic magnetic pole pair is calculated. The magnetic absolute position value is obtained based on the fine electrical angle and the coarse absolute position of the magnetic encoder.
[0016] In one possible implementation of the first aspect, the magnetic absolute position value is obtained based on the fine electrical angle and the coarse absolute position of the magnetic encoder, including: Based on the coarse absolute position, the magnetic reference position is determined according to the preset characteristic pole pair unit angle range; The magnetic reference position and the data mapped to the characteristic pole pair unit angle range are added together to obtain the summation result; The magnetic absolute position value is obtained based on the summation result.
[0017] In one possible implementation of the first aspect, the non-fault state also includes a qualified state and an alarm state, and the method further includes: outputting a warning message when the magnetic sensitive element in the magnetic absolute encoder or the photosensitive element in the optical incremental encoder is in an alarm state.
[0018] In one possible implementation of the first aspect, the evaluation conditions for magnetic coding characteristic parameters corresponding to the non-fault state include the evaluation conditions for magnetic coding characteristic parameters corresponding to the qualified state and the evaluation conditions for magnetic coding characteristic parameters corresponding to the alarm state. Furthermore, the magnetic sensitive element is determined to be in an alarm state by the following method: when the actual characteristic parameter value of the magnetic encoder of the magnetic sensitive element meets the evaluation condition of the magnetic encoder characteristic parameter corresponding to the alarm state, the magnetic sensitive element is determined to be in an alarm state. The photosensitive element is determined to be in an alarm state by the following method: when the actual optical encoder characteristic parameter value of the photosensitive element meets the evaluation conditions of the optical encoder characteristic parameter corresponding to the alarm state, the photosensitive element is determined to be in an alarm state.
[0019] In a second aspect, an absolute value encoding system for an optical-magnetic encoder is provided, including an optical incremental encoder and a magnetic absolute encoder, a processing unit and a storage unit, wherein the storage unit stores a computer program / instruction, causing the processing unit to execute an absolute value encoding method for an optical-magnetic encoder that implements any one of the first aspect and various possible implementations of the first aspect according to the stored computer program / instruction.
[0020] Thirdly, a computer program product is provided, including a computer program / instruction, which, when executed by a processor in an encoder system, implements the absolute value encoding method of an optical-magnetic encoder according to any one of the first aspects and various possible implementations thereof. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 According to some embodiments of this application, an absolute value encoding method for an optical-magnetic encoder is shown.
[0023] Figure 2 According to some embodiments of this application, a schematic diagram of a specific process for determining the optical coding reference characteristic parameters of an optical incremental encoder and the magnetic coding reference characteristic parameters of a magnetic absolute encoder is shown.
[0024] Figure 3 According to some embodiments of this application, a schematic diagram is shown of a magnetic voltage signal obtained by a certain magnetic sensing element sensing 14 pairs of non-uniformly spaced pole magnets in one mechanical revolution.
[0025] Figure 4 According to some embodiments of this application, a schematic diagram of a process for identifying whether an optical incremental encoder and a magnetic absolute encoder have malfunctioned is shown.
[0026] Figure 5 According to some embodiments of this application, a schematic diagram of a specific method for obtaining the magnetic absolute position value of a magnetic absolute encoder is shown. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0028] As shown in the background art, using a single optical encoder or magnetic encoder in the production and use process often fails to obtain a high-precision absolute position value due to issues such as environmental adaptability and process cost.
[0029] Therefore, to solve the above problems, this application provides an absolute value encoding method for an optical-magnetic encoder. In this method, the encoder system obtains the required final absolute position value based on the fusion of a magnetic absolute encoder and an optical incremental encoder. Specifically, when both the magnetic absolute encoder and the optical incremental encoder are in a non-faulty state, a fused absolute position value is obtained based on the magnetic absolute position value of the magnetic absolute encoder and the optical incremental value of the optical incremental encoder. This fused absolute position value serves as the output absolute position value of the encoder system, i.e., the final absolute position value. The magnetic absolute position value of the magnetic absolute encoder is used to determine the optical reference position of the optical incremental encoder. The magnetic absolute position value has a first precision, and the fused absolute position value has a second precision, which is higher than the first precision.
[0030] Understandably, optical encoders generally have higher accuracy than magnetic encoders. For example, in one mechanical cycle, an optical encoder corresponds to 1024 electrical cycles, while a magnetic encoder corresponds to 14 electrical cycles, hence the higher accuracy of optical encoders. After obtaining the magnetic absolute position value of a magnetic absolute encoder, the optical reference position value of an optical incremental encoder can be obtained. Adding the optical reference position value of the optical incremental encoder to the optical increment value yields a highly accurate fused absolute position value. In this way, a highly accurate output absolute position value can be obtained without the more complex manufacturing process of an optical absolute encoder, thus reducing costs. Furthermore, the absolute position value of a magnetic absolute encoder is only used for reference positioning, allowing it to adapt to a wider range of environments.
[0031] Understandably, by integrating a magnetic absolute encoder with an optical incremental encoder, the advantages of both can be complemented. The magnetic absolute encoder can be used for coarse positioning and safety assurance by utilizing its absolute position measurement and strong environmental adaptability, while the optical incremental encoder can be used for precise positioning by utilizing its extremely high resolution. Finally, the two signals are fused to output a stable, accurate, and reliable absolute position information.
[0032] Furthermore, after obtaining the reference position of the optical incremental encoder based on the magnetic absolute encoder, the optical incremental encoder only needs to be used as the main position tracking source. The magnetic absolute encoder only needs to run at a low frequency in the background for periodic calibration and redundant monitoring, without continuous operation, which can save operating resources.
[0033] In other embodiments, when it is determined that the optical incremental encoder is in a fault state and the magnetic absolute encoder is in a non-fault state, the magnetic absolute position value can be output as the output absolute position value.
[0034] Understandably, when the optical incremental encoder output fails, the magnetic absolute position value output of the magnetic absolute encoder can be used seamlessly. This allows for the accurate absolute position value of the mechanical component movement to be obtained even when the optical incremental encoder fails, ensuring that a single sensor failure does not cause the system to crash and greatly improving the mean time between failures (MTBF).
[0035] Furthermore, in some embodiments, multiple magnetic sensing elements can be redundantly designed for magnetic absolute encoders. For example, a magnetic absolute encoder may include 12 magnetic sensing elements, of which 3 magnetic sensing elements serve as backups. When a fault is detected in a magnetic sensing element, the magnetic absolute position value can still be obtained based on the backup magnetic sensing elements.
[0036] Correspondingly, when the optical encoder is in a non-fault state, it includes: each photosensitive element in the optical incremental encoder is in a non-fault state; when the magnetic absolute encoder is in a non-fault state, it includes: a first preset number of magnetic sensitive elements in the magnetic absolute encoder are in a non-fault state, the first preset number being the minimum number that can complete absolute position decoding.
[0037] It's understandable that redundant design of optical-magnetic encoders improves system reliability. Specifically, the optical encoder and magnetic encoder are mutually redundant. In the event of a failure in the optical incremental encoder, the required final absolute position value can be obtained based on the magnetic absolute encoder. Since the optical incremental encoder has already determined the reference position through the magnetic absolute encoder, if the subsequent magnetic absolute encoder fails during operation, the optical incremental encoder can still obtain the currently required final absolute position value. Furthermore, among the multiple magnetic sensing elements included in the magnetic absolute encoder, several are backups. When a failure of a magnetic sensing element is detected, the magnetic absolute position value can still be obtained based on the backup magnetic sensing elements, achieving redundancy at both the hardware and software levels, thereby meeting the performance requirements of high reliability and long-term use.
[0038] Figure 1 According to some embodiments of this application, an absolute value encoding method for an optical-magnetic encoder is shown. It is understood that this method is applied to an encoder system, which includes an optical incremental encoder and a magnetic absolute value encoder. The specific process is as follows: S101, determine the optical encoder reference characteristic parameter value of the optical incremental encoder and the magnetic encoder reference characteristic parameter value of the magnetic absolute encoder, and pre-store them in the memory. Understandably, the optical encoder reference characteristic parameter value and the magnetic encoder reference characteristic parameter value can be used to determine whether the optical incremental encoder and the magnetic absolute encoder are in a fault state.
[0039] In some embodiments, the optical incremental encoder may include multiple photosensitive elements. The optical encoder reference characteristic parameter values include: the optical offset reference value Offset_Opt_A and the optical amplitude reference value Amplitude_Opt_A corresponding to the sine signal of the A-channel photosensitive element, and the optical offset reference value Offset_Opt_B and the optical amplitude reference value Amplitude_Opt_B corresponding to the cosine signal of the B-channel photosensitive element.
[0040] In some embodiments, the magnetic absolute encoder may include multiple magnetic sensing elements. The magnetic encoder reference characteristic parameter values include: magnetic offset reference values Offset_Mag_M1 to Offset_Mag_M12 corresponding to each of the 12 magnetic sensing elements, and magnetic amplitude reference values Amplitude_Mag_M1 to Amplitude_Mag_M12.
[0041] Understandably, the optical reference characteristic parameter values for the optical incremental encoder and the magnetic reference characteristic parameter values for the magnetic absolute encoder can be packaged into separate data structures. This data structure is then written into the non-volatile Flash memory of the encoder system processing unit. After the system powers on, the main program first reads these calibration parameters from the Flash memory before performing any angle calculations.
[0042] S102, during the power-on initialization phase, when both the magnetic absolute encoder and the optical incremental encoder are in a non-fault state, a fused absolute position value is obtained based on the magnetic absolute position value output by the magnetic absolute encoder and the optical incremental value of the optical incremental encoder. The fused absolute position value is used as the output absolute position value, wherein the magnetic absolute position value is used to obtain the optical reference position value of the optical incremental encoder. When the magnetic absolute encoder is in a non-fault state and the optical incremental encoder is in a fault state, the magnetic absolute position value is used as the output absolute position value.
[0043] Understandably, during the power-on initialization phase, the operating conditions of both the optical incremental encoder and the magnetic absolute encoder can be identified to determine if they are in a fault state. Based on the specific fault condition of each encoder, different methods are used to determine the output absolute position value. Furthermore, if the magnetic absolute encoder is in a fault state, it is determined that no absolute position value can be output.
[0044] In some embodiments, when the system is powered on, the magnetic absolute encoder can instantly output a magnetic absolute position value. Based on this magnetic absolute position value, the optical reference position θ_magnet of the optical incremental encoder can be determined, which can subsequently serve as the "coarse position" reference for the entire system. Then, position fusion is performed. Specifically, the encoder system begins reading the optical encoder signal from the optical incremental encoder to determine a high-precision optical increment value Δθ_optical, i.e., the relative displacement. The optical reference position θ_magnet obtained from the magnetic absolute encoder is added to the optical increment value Δθ_optical from the optical incremental encoder to obtain the fused absolute position value θ_final (i.e., θ_final = θ_magnet + Δθ_optical).
[0045] In other embodiments, the optical incremental encoder can be used as the output position value path for the fused absolute position values. When the fused absolute position value is needed as the output absolute position value, i.e., both the optical incremental encoder and the magnetic absolute encoder are in a non-fault state, the output position value path of the encoder system is the optical incremental encoder. When the magnetic absolute position value is needed as the output absolute position value, i.e., the optical incremental encoder is in a fault state and the magnetic absolute encoder is in a non-fault state, the output position value path of the encoder system is the magnetic absolute encoder.
[0046] Furthermore, when the optical incremental encoder and magnetic absolute encoder are in a non-faulty state, this state can be further divided into a qualified state and an alarm state. When the optical incremental encoder and magnetic absolute encoder are in an alarm state, warning messages can be output to alert personnel.
[0047] Table 1 below shows the output position value path correspondence for various operating conditions (fault and non-fault) of an optical and magnetic encoder. The non-fault state within the operating condition types can be further divided into qualified state and alarm state.
[0048] Table 1 S103, during normal operation, continuously obtains updated output absolute position values based on the light increment values updated by the light increment encoder.
[0049] In some embodiments, during normal operation, the optical incremental encoder is continuously used as the primary position tracking source because it provides the smoothest and finest position changes. The magnetic absolute encoder operates in the background at a lower frequency, its role becoming periodic calibration and redundant monitoring. Specifically, the magnetic absolute position value of the magnetic absolute encoder can be periodically compared with the fused absolute position value obtained based on the current optical incremental value of the optical incremental encoder. If a large discrepancy exists, the optical reference position of the optical incremental encoder is re-determined based on the current magnetic absolute position value.
[0050] In addition, the system periodically checks for malfunctions in the optical incremental encoder and the magnetic absolute encoder. If the optical incremental encoder malfunctions, the magnetic absolute position value obtained from the magnetic absolute encoder is used as the output absolute position value. If the magnetic absolute encoder malfunctions, the updated output absolute position value is obtained based on the updated optical incremental value from the optical incremental encoder. It is understood that the description of the output position value path in S102 above also applies to this stage, and will not be elaborated upon here. The following is combined Figure 2 This section details the specific process of determining the optical coding reference characteristic parameters of the optical incremental encoder and the magnetic coding reference characteristic parameters of the magnetic absolute encoder in S101.
[0051] S201, Hardware Connection and Device Preparation.
[0052] In some embodiments, on the motor production line, suitable testing fixtures are selected to securely mount the motor with both an optical incremental encoder and a magnetic absolute encoder onto a testing platform. A stable power supply is prepared to provide the motor with an adjustable drive voltage.
[0053] S202, motor drive and stable operation.
[0054] In some embodiments, a suitable initial drive voltage is applied to the motor through a power supply device. After starting the motor, the operating status of the motor is observed. Since the motor speed will fluctuate during the startup process, it is necessary to wait for a period of time until the motor speed stabilizes.
[0055] S203, optical encoding signal acquisition and processing, to obtain the optical encoding reference characteristic parameter values.
[0056] The drive motor rotates at a constant speed for at least one complete mechanical cycle under no-load conditions. The optical encoder is configured to enter the calibration state via communication. The controller collects the original sine and cosine signals of each photosensitive element in real time at a fixed sampling frequency. Specifically, based on the real-time acquired optical encoding signals of photosensitive elements A and B, the peak value and trough value of each electrical cycle are determined within a complete mechanical cycle, corresponding to 1024 complete bright and dark cycles of the grating code disk. For channel A (corresponding to photosensitive element A), the arithmetic mean of the peak values of the 1024 electrical cycles is taken as the global peak value MaxA of the channel, and the arithmetic mean of the trough values of the 1024 electrical cycles is taken as the global trough value MinA of the channel. Similarly, for channel B (corresponding to photosensitive element B), the global peak value MaxB and the global trough value MinB are obtained. According to the DC bias calculation formula (1) and the amplitude calculation formula (2), the bias reference values Offset_Opt_A, Offset_Opt_B and the amplitude reference values Amplitude_Opt_A, Amplitude_Opt_B of each photosensitive element are determined respectively.
[0057] The expression for the DC bias calculation formula is as follows (1).
[0058] Offset = (Max+ Min) / 2 formula (1); Where Offset represents the offset value, Max represents the peak value, and Min represents the trough value.
[0059] The expression for the amplitude calculation formula is as follows (2).
[0060] Amplitude = (Max – Min) / 2 formula (2); Amplitude represents the amplitude value.
[0061] Understandably, peaks and troughs can be determined by the rising and falling edges of the waveform. Peaks have a rising edge on the left and a falling edge on the right, while troughs have a falling edge on the left and a rising edge on the right.
[0062] S204, magnetic encoder signal acquisition and processing, to obtain magnetic encoder reference characteristic parameter values.
[0063] Similarly, once the motor speed stabilizes, the optical encoder enters calibration mode via communication configuration. The controller collects the raw signals of each magnetic sensor element in real time at a fixed sampling frequency. Specifically, based on the real-time collected magnetic encoder signals from the 12 magnetic sensors M1~M12, the peak and trough values of each electrical cycle are determined within a complete mechanical cycle, corresponding to the 14 pairs of non-uniform pole pitch magnets. For the Mx channel, the maximum value PeakMx_max is determined from the 14 peak values, and the arithmetic mean of the peak values for the remaining 13 cycles (excluding the cycle corresponding to the maximum value) is calculated and denoted as MaxMx. The minimum value ValleyMx_max is determined from the 14 trough values, and the arithmetic mean of the trough values for the remaining 13 cycles (excluding the cycle corresponding to the minimum value) is calculated and denoted as MinMx. According to the DC bias calculation formula (1) and the amplitude calculation formula (2), the bias reference values Offset_Mag_M1~Offset_Mag_M12 and the amplitude reference values Amplitude_Mag_M1~Amplitude_Mag_M12 of each magnetic sensitive element are determined respectively.
[0064] For example, each magnetic sensing element, in one mechanical cycle, senses 14 periodic voltage waveforms generated by 14 pairs of non-uniformly spaced pole magnets, including a first characteristic pair with one electrical cycle and a second characteristic pair with 13 electrical cycles. Figure 3 This diagram illustrates the magnetic voltage signal obtained by a magnetically sensitive element inducing 14 pairs of non-uniformly spaced pole magnets during one mechanical revolution. Figure 3 As shown, the waveform contains the first and second characteristic poles. At this time, for each magnetic sensitive element M1~M12, there will be 14 sets of peak values and valley values after one mechanical cycle. The 14 sets of peak values and 14 sets of valley values for each magnetic sensitive element M1~M12 are obtained respectively. For magnetic sensitive element M1, the peak value is calculated to obtain the peak value PeakM1_max corresponding to the first characteristic pole. The peak value is averaged after removing the maximum value to obtain the peak value MaxM1 corresponding to the second characteristic pole. Similarly, the valley value ValleyMx_max corresponding to the first characteristic pole and the valley value MinM1 corresponding to the second characteristic pole are obtained. The magnetic bias reference value Offset_Mag_M1 is obtained according to the calculation method of formula (1). The magnetic amplitude reference value Amplitude_Mag_M1 is obtained according to the calculation method of formula (2).
[0065] S205, solidify the magnetic coding reference characteristic parameter values and the optical coding reference characteristic parameter values into the memory.
[0066] In some embodiments, the optical encoder reference characteristic parameter values (optical offset reference values Offset_Opt_A, Offset_Opt_B, optical amplitude reference values Amplitude_Opt_A, Amplitude_Opt_B), i.e., the calibration parameters, and the optical encoder reference characteristic parameter values (magnetic offset reference values Offset_Mag_M1~Offset_Mag_M2, magnetic amplitude reference values Amplitude_Mag_M1~Amplitude_Mag_M12) of the magnetic absolute encoder are packaged into a calibration data structure. This data structure is written into the non-volatile Flash memory of the processing unit MCU. After the system powers on, before performing any angle calculation, the main program first reads these magnetic and optical encoder reference characteristic parameter values from the Flash memory for calibration.
[0067] The following is combined Figure 4 This section details the operating condition (i.e., whether a fault has occurred) of the optical incremental encoder and magnetic absolute encoder identified in S102. The specific process is as follows: S401, acquire the original optical encoding signal and the original magnetic encoding signal.
[0068] Understandably, the original optical encoder signal includes the optical encoder signal acquired in real time by the optical incremental encoder during one mechanical cycle, and the original magnetic encoder signal includes the magnetic encoder signal acquired in real time by the magnetic absolute encoder during one mechanical cycle.
[0069] S402 determines the actual characteristic parameter values of optical encoding based on the original optical encoding signal and the optical encoding reference characteristic parameters.
[0070] Understandably, after acquiring the original optical encoding signal, the original optical encoding signal is debiased and normalized based on the optical encoding reference characteristic parameters pre-stored in the non-volatile memory to obtain the calibrated optical encoding signals Opt_A_norm and Opt_B_norm.
[0071] The actual characteristic parameter values of the optical encoder include: normalized amplitude deviation, residual bias, and normalized instantaneous radius.
[0072] In some embodiments, the normalized instantaneous radius at the current sampling time is calculated from the calibrated optical encoder signals Opt_A_norm and Opt_B_norm, and used as the basis for calculating the Lissajous figure roundness eigenvalue. Specifically, the normalized instantaneous radius is calculated according to the following formula (3): Sqrt((Opt_A_norm)² + (Opt_B_norm)² )= R norm formula (3); Where Sqrt() represents the square root function, R norm is the normalized instantaneous radius calculated in real time. Its theoretical value is 1 under ideal fault-free conditions. It is used for the calculation of the roundness characteristic value of the Lissajous figure and subsequent fault assessment.
[0073] S403, the actual characteristic parameter values of the optical encoder are compared with the preset evaluation conditions for optical encoder characteristic parameters corresponding to each working condition type, and the corresponding optical encoder working condition type is determined based on the comparison result. Each working condition type includes a fault state and a non-fault state. In some embodiments, the non-fault state also includes a qualified state and an alarm state. When the optical incremental encoder is in an alarm state, an alarm prompt is output to alert technicians to potential fault risks. If the evaluation condition corresponding to any photosensitive element is determined to be a fault state, the optical incremental encoder is determined to be in a fault state.
[0074] The evaluation conditions for the optical encoder's characteristic parameters include: normalized amplitude deviation evaluation conditions, residual DC offset evaluation conditions, Lissajous figure roundness evaluation conditions, and channel gain consistency evaluation conditions. It is understood that by comparing the actual characteristic parameter values of the optical encoder with the specific evaluation conditions, the cause of the fault can be indicated to the troubleshooting personnel, facilitating repair.
[0075] (1) Specifically, when the operating condition includes fault state and non-fault state, the normalized amplitude deviation evaluation condition is as follows: calculate the amplitude AmpA_norm of Opt_A_norm and the amplitude AmpB_norm of Opt_B_norm within a complete signal cycle window; if AmpA_norm or AmpB_norm exceeds the preset normalized amplitude allowable range, the operating condition type is determined according to the degree of exceedance. For example, the normalized amplitude allowable range and the corresponding operating condition type division are shown in Table 2 below: Table 2 Here, Amp_norm refers to AmpA_norm or AmpB_norm. If any channel exceeds the corresponding range, the operating condition type is determined according to the table above.
[0076] (2) Specifically, when the operating condition includes both fault and non-fault states, the residual DC offset evaluation condition is as follows: calculate the DC offset OffsetA_norm of Opt_A_norm and the DC offset OffsetB_norm of Opt_B_norm within a complete signal cycle window; if OffsetA_norm or OffsetB_norm exceeds the preset residual DC offset allowable range, the operating condition type is determined according to the degree of exceedance. For example, the residual DC offset allowable range and the corresponding operating condition type divisions are shown in Table 3 below: Table 3 Here, Offset_norm refers to OffsetA_norm or OffsetB_norm. If any channel exceeds the corresponding range, the operating condition type is determined according to the table above.
[0077] (3) Specifically, when the operating condition includes both fault and non-fault states, the Lissajous figure roundness evaluation condition is as follows: Calculate the normalized instantaneous radius R_norm = sqrt( Opt_A_norm² + Opt_B_norm²) for each sampling point within a complete signal period window, and statistically analyze the maximum value Rmax, minimum value Rmin, and average value Rmean of R_norm within the window. Calculate the radius volatility Ripple_norm = (Rmax - Rmin) / Rmean. If Ripple_norm exceeds the preset radius volatility allowable range, the operating condition type is determined based on the degree of exceedance. For example, the radius volatility allowable range and the corresponding operating condition type classification are shown in Table 4 below: Table 4 (4) Specifically, when the operating condition includes fault state and non-fault state, the channel gain consistency evaluation condition is as follows: Calculate the channel gain imbalance within a complete signal cycle window using the following formula: Gain_Imb = (|AmpA_norm) / (|AmpA_norm) AmpB_norm∣) / (max(AmpA_norm,AmpB_norm)). Where Gain_Imb represents the gain consistency of the two signal channels; the smaller the value, the closer the gains of the two channels are. max() represents taking the larger of the two values. If the channel gain imbalance Gain_Imb exceeds a preset allowable range, the operating condition type is determined based on the degree of excess. For example, the allowable range of channel gain imbalance and the corresponding operating condition types are shown in Table 5 below: Table 5 S404 determines the actual characteristic parameter values of magnetic coding based on the original magnetic coding signal and the magnetic coding reference characteristic parameters.
[0078] Understandably, after acquiring the original magnetic coding signal, the original magnetic coding signal is debiased and amplitude normalized based on the magnetic coding reference characteristic parameters pre-stored in the non-volatile memory to obtain the calibrated magnetic coding signals Mag_M1_norm~Mag_M12_norm.
[0079] The actual characteristic parameter values of the magnetic encoder include: normalized amplitude deviation, residual bias, and normalized instantaneous radius.
[0080] For example, the magnetic absolute encoder includes 12 magnetic sensitive elements M1 to M12. Based on the placement characteristics of the 12 magnetic sensitive elements, magnetic sensitive elements Mx and M(x+1) are simultaneously located at the first characteristic magnetic pole pair, while the remaining adjacent magnetic sensitive elements are all located at the second characteristic magnetic pole pair. The normalized instantaneous radius is calculated by formula (3) from the calibrated signals Mag_My_norm to Mag_M(y+1)_norm of the two magnetic sensitive elements My and M(y+1) located at the second characteristic magnetic pole pair. This normalized instantaneous radius is used for the calculation of the Lissajous figure roundness characteristic value and subsequent fault assessment.
[0081] S405, compare the actual characteristic parameter values of the magnetic encoder with the preset evaluation conditions for the characteristic parameters of the magnetic encoder corresponding to each working condition type, and determine the corresponding magnetic encoder working condition type based on the comparison result. Each working condition type includes a fault state and a non-fault state. In some embodiments, the non-fault state further includes a qualified state and an alarm state.
[0082] In the positioning and decoding process of the magnetic absolute encoder, the encoder is considered to be faulty only when a first preset number of magnetic sensing elements cannot be in a non-faulty state. The first preset number is the minimum number required to complete absolute position decoding. For example, for 12 magnetic sensing elements, 9 magnetic sensing element signals are sufficient to obtain the absolute position, and 3 signals are used for redundancy backup. The magnetic absolute encoder is considered to be faulty only when a maximum of 3 magnetic sensing signals fail.
[0083] Specifically, for two adjacent magnetic sensing elements My and M(y+1) located at the second characteristic magnetic pole pair, the evaluation conditions for the magnetic coding characteristic parameters include: normalized amplitude deviation evaluation condition, residual DC offset evaluation condition, Lissajous figure roundness evaluation condition, and channel gain consistency evaluation condition. It should be understood that the evaluation conditions currently only apply to the magnetic sensing element signal corresponding to the second characteristic magnetic pole pair; the magnetic sensing element signal located at the first characteristic magnetic pole pair is not included in this fault assessment scope.
[0084] (1) Specifically, when the operating condition type includes fault state and non-fault state, the normalized amplitude deviation evaluation condition is as follows: calculate the amplitudes AmpMy_norm of Mag_My_norm and AmpM(y+1)_norm of Mag_M(y+1)_norm within a complete signal cycle window; if AmpMy_norm or AmpM(y+1)_norm exceeds the preset normalized amplitude allowable range, the operating condition type is determined according to the degree of exceedance. For example, the normalized amplitude allowable range and the corresponding operating condition type division are shown in Table 6 below: Table 6 Here, Amp_norm refers to AmpMy_norm or AmpM(y+1)_norm. If any channel exceeds the corresponding range, the operating condition type is determined according to the table above.
[0085] (2) Specifically, when the operating condition includes both fault and non-fault states, the residual DC offset evaluation condition is as follows: calculate the DC offsets OffsetMy_norm of Mag_My_norm and OffsetM(y+1)_norm of Mag_M(y+1)_norm within a complete signal cycle window; if OffsetMy_norm or OffsetM(y+1)_norm exceeds the preset residual DC offset allowable range, the operating condition type is determined according to the degree of exceedance. For example, the residual DC offset allowable range and the corresponding operating condition type divisions are shown in Table 7 below: Table 7 Here, Offset_norm refers to OffsetMy_norm or OffsetM(y+1)_norm. If any channel exceeds the corresponding range, the operating condition type is determined according to the table above.
[0086] (3) Specifically, when the operating condition includes both fault and non-fault states, the Lissajous figure roundness evaluation condition is as follows: Calculate the normalized instantaneous radius R_norm = sqrt( Mag_My_norm² + Mag_M(y+1)_norm(n)²) for each sampling point within a complete signal period window, count the maximum value Rmax, minimum value Rmin, and average value Rmean of R_norm within the window, and calculate the radius volatility Ripple_norm = (Rmax - Rmin) / Rmean. If Ripple_norm exceeds the preset radius volatility allowable range, the operating condition type is determined according to the degree of exceedance. For example, the radius volatility allowable range and the corresponding operating condition type division are shown in Table 8 below: Table 8 (4) The evaluation condition for channel gain consistency is as follows: within a complete signal period window, calculate the channel gain imbalance according to the following formula: Gain_Imb=(|AmpMy_norm AmpM(y+1)_norm∣) / (max(AmpMy_norm,AmpM(y+1)_norm)). Where Gain_Imb represents the gain consistency of the two signal channels; the smaller the value, the closer the gains of the two channels are. max() represents taking the larger of the two values. If the channel gain imbalance Gain_Imb exceeds the preset allowable range, the operating condition type is determined according to the degree of excess. For example, the allowable range of channel gain imbalance and the corresponding operating condition types are shown in Table 9 below: Table 9 The following is combined Figure 5 This section details how the magnetic absolute position value of the magnetic absolute encoder in S102 is obtained. The specific process is as follows: S501 obtains a multi-dimensional measurement vector based on the current calibrated magnetic encoder signal corresponding to the magnetic sensor in a non-faulty state among the various magnetic sensor elements.
[0087] In some embodiments, when the system is powered on or running, the microprocessor in the encoder system reads the signals of the non-faulty magnetic sensing elements among the 12 magnetic sensing elements in real time. This signal is the currently calibrated magnetic encoder signal, which can form a current multidimensional measurement vector. For example, when all 12 magnetic sensing elements are in a non-faulty state, a 12-dimensional measurement vector [V1_m, V2_m, ..., V12_m] is obtained.
[0088] S502 matches the multidimensional measurement vector with a pre-stored mechanical angle lookup table to obtain the coarse absolute position of the magnetic absolute encoder.
[0089] Understandably, the system will have a pre-built mechanical angle lookup table. For example, before the magnetic absolute encoder leaves the factory, it is driven to rotate a full circle on a high-precision turntable. Every 1°, the vector [V1, V2, V3, ..., V12] output by the 12 magnetic sensing elements is recorded. This vector, along with its corresponding actual mechanical absolute position θ_coarse, is stored in a lookup table, thus obtaining the mechanical angle lookup table.
[0090] In some embodiments, the multidimensional measurement vector is compared with all reference vectors in a mechanical angle lookup table stored in ROM. A minimum mean square error algorithm is used to find the best-matching reference vector. Once the best match is found, the corresponding θ_coarse value in the mechanical angle lookup table is read and used as the coarse absolute position output θ_coarse of the magnetic absolute encoder. The accuracy of this θ_coarse corresponds to the resolution of the mechanical angle lookup table (one point per 1°, so the initial error of θ_coarse is within ±0.5°). During the coarse positioning process of the magnetic absolute encoder, θ_coarse can be obtained based on the signals from 9 magnetic sensing elements.
[0091] S503 determines the magnetic pole pair where each magnetic sensitive element is located based on the coarse absolute position of the magnetic encoder.
[0092] In some embodiments, after determining θ_coarse using a mechanical angle lookup table, the position of each magnetic sensing element can be obtained. That is, the current magnetic pole pair of each magnetic sensing element can be determined (e.g., θ_coarse = 20°, magnetic sensing element m1 is in the first pole pair), and the system will switch to high-precision mode.
[0093] S504, based on the magnetic coding signals corresponding to the two adjacent target magnetic sensitive elements located within the second characteristic magnetic pole, calculates the fine electrical angle within the period of the second characteristic magnetic pole pair.
[0094] In some embodiments, from the currently calibrated magnetic coding signals corresponding to the magnetically sensitive elements that are in a non-faulty state among the various magnetically sensitive elements, the magnetic coding signals corresponding to the two adjacent target magnetically sensitive elements located directly above the second characteristic magnetic pole and having the best signal quality are selected (thus obtaining a pair of sine and cosine signals). Due to the unique design of the magnet and the placement of the magnetically sensitive elements, the magnetic field distribution within the second characteristic magnetic pole (within approximately a 24° mechanical angle) is approximately sinusoidal. Therefore, selecting two adjacent magnetically sensitive elements within the second characteristic magnetic pole results in their outputs forming sine and cosine wave signals V_sin and V_cos with equal amplitude and a 90° phase difference. Using these two values, the fine electrical angle φ_fine within the period of this magnetic pole pair is calculated using the arctangent function. For example, φ_fine = arctan2(V_sin, V_cos).
[0095] S505 obtains the magnetic absolute position value based on the fine electrical angle and the coarse absolute position of the magnetic encoder.
[0096] In some embodiments, after determining θ_coarse based on a mechanical angle lookup table, the magnetic reference position is determined according to a preset characteristic pole pair unit angle range, where the magnetic reference position is an integer multiple of the characteristic pole pair unit angle range. The magnetic reference position is then added to the data of the fine electrical angle under the same characteristic pole pair unit angle range, and the absolute magnetic position value is obtained based on the addition result.
[0097] For example, the unit angle range of the characteristic pole pair is a mechanical angle. It can be understood that the first characteristic pole pair corresponds to a range of 48°, while each second characteristic pole pair corresponds to a range of 24°; that is, one first characteristic pole pair is equivalent to the range of two second characteristic pole pairs. For the second characteristic pole pair, one electrical cycle corresponds to one pole pair, which is approximately 24° of mechanical angle, meaning the unit angle range of the characteristic pole pair can be 24°. Mapping the fine electrical angle φ_fine back to the mechanical angle based on the unit angle range of the characteristic pole pair yields a fine offset, which is a fine mechanical offset Δθ_fine relative to the starting point of the second characteristic pole pair. The magnetic reference position θ_c is determined based on the coarse position θ_coarse obtained from the lookup table. It is then added to the fine offset Δθ_fine obtained by arcsine interpolation. The sum is quantized to the range of the magnetic absolute position value. For example, if the range of the magnetic absolute position value is 0-360°, the sum is directly used as the final high-precision absolute position θ_magnet of the magnetic absolute encoder (θ_magnet = θ_c + Δθ_fine).
[0098] For example, the eigenpole pair unit angle range is a digital quantization range, such as 65536 for 24°. Assuming the current θ_coarse is between [2*24°, 3*24°], the magnetic reference position is 2*65536. Assuming the fine electrical angle is 5000, 2*65536 is added to 5000, and the result is quantized to the range of the magnetic absolute position value. For example, if the range of the magnetic absolute position value is 0-65536, the result is divided by 15.
[0099] Understandably, the magnetic encoder design employing "non-uniform magnetic poles + multi-channel sampling lookup table + local sine interpolation" in this embodiment ensures that even in the extreme case of complete failure of the optical incremental encoder, the system does not degrade to a coarse lookup table positioning mode. Instead, it can still operate in a high-precision magnetic positioning mode based on the magnetic absolute encoder using "lookup table + interpolation." This means that the performance in the degraded mode is far superior to that of traditional pure lookup table methods or low-resolution magnetic encoders, providing the possibility for the system to maintain high performance under fault conditions.
[0100] Furthermore, it achieves both high precision and absolute position: solving the problem that a single encoder cannot simultaneously handle extremely high resolution and absolute position. It achieves "power-on and ready to use, precise operation." Under normal conditions, the low-noise, high-response optical incremental encoder signal dominates, ensuring the servo system has excellent dynamic characteristics.
[0101] Excellent environmental adaptability: The robustness of the magnetic absolute encoder compensates for the environmental cleanliness requirements of the optical incremental encoder, enabling the entire system to cope with a wider range of working conditions.
[0102] Intelligent system health management: The processing unit can continuously monitor the status and output consistency of the two encoders, enabling predictive maintenance and providing early warnings before problems occur.
[0103] This application also provides an absolute value encoding system for an optical-magnetic encoder, including an optical incremental encoder and a magnetic absolute encoder, a processing unit and a storage unit. The storage unit stores a computer program / instruction, causing the processing unit to execute the absolute value encoding method of the optical-magnetic encoder according to the stored computer program / instruction, thereby implementing any embodiment of the optical-magnetic encoder. For example, implementing... Figure 1 The absolute value encoding method of the optical-magnetic encoder is shown.
[0104] This application also provides a computer program product, including a computer program / instructions, which, when executed by a processor in an encoder system, implement the absolute value encoding method of an optical-magnetic encoder according to any embodiment. For example, implementing... Figure 1 The absolute value encoding method of the optical-magnetic encoder is shown. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.
[0105] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. An absolute value encoding method for an optical-magnetic encoder, characterized in that, Applied to encoder systems, which include optical incremental encoders and magnetic absolute encoders; The method includes: When both the magnetic absolute encoder and the optical incremental encoder are in a non-faulty state, a fused absolute position value is obtained based on the magnetic absolute position value of the magnetic absolute encoder and the optical incremental value of the optical incremental encoder. The fused absolute position value is used as the output absolute position value of the encoder system. The magnetic absolute position value of the magnetic absolute encoder is used to determine the optical reference position of the optical incremental encoder. The magnetic absolute position value has a first precision, and the fused absolute position value has a second precision, wherein the second precision is higher than the first precision.
2. The method according to claim 1, characterized in that, The method further includes: When the optical incremental encoder is in a fault state and the magnetic absolute encoder is in a non-fault state, the magnetic absolute position value is used as the output absolute position value.
3. The method according to claim 1 or 2, characterized in that, The optical incremental encoder being in a non-fault state includes: each photosensitive element in the optical incremental encoder being in a non-fault state. The magnetic absolute encoder being in a non-fault state includes: the magnetic absolute encoder having a first preset number of magnetic sensitive elements in a non-fault state, where the first preset number is the minimum number capable of completing absolute position decoding.
4. The method according to claim 3, characterized in that, The optical incremental encoder is determined to be in a non-faulty state by the following method: Obtain the original signals currently output by each photosensitive element of the optical incremental encoder; Based on the original signals of each photosensitive element and the pre-stored optical coding reference characteristic parameter values, the actual optical coding characteristic parameter values of each photosensitive element used for fault diagnosis are determined; wherein, the optical coding reference characteristic parameter values include: optical bias reference value and optical amplitude reference value; the actual optical coding characteristic parameter values include: normalized amplitude deviation, residual bias amount, and Lissajous figure roundness characteristic value calculated within one signal period window after the original signals of each photosensitive element have undergone debiasing and amplitude normalization processing; If all the actual characteristic parameter values of the optical encoder meet the evaluation conditions of the optical encoder characteristic parameters corresponding to the non-fault state, it is determined that each photosensitive element in the optical incremental encoder is in a non-fault state. The evaluation conditions of the optical encoder characteristic parameters include: normalized amplitude deviation evaluation condition, residual DC offset evaluation condition, Lissajous figure roundness evaluation condition, and channel gain consistency evaluation condition.
5. The method according to claim 3, characterized in that, The magnetic sensitive element in the absolute magnetic encoder is determined to be in a non-faulty state by the following methods: Obtain the raw signals of the current output of each magnetic sensitive element of the magnetic absolute encoder; Based on the original signals of each magnetic sensitive element and the pre-stored magnetic coding reference characteristic parameter values, the actual magnetic coding characteristic parameter values of each magnetic sensitive element used for fault diagnosis are determined; wherein, the magnetic coding reference characteristic parameter values include: magnetic bias reference value and magnetic amplitude reference value; the actual magnetic coding characteristic parameter values include: normalized amplitude deviation, residual bias amount, and Lissajous figure roundness characteristic value calculated within one signal period window after the original signals of each magnetic sensitive element have undergone debiasing and amplitude normalization processing; When all the actual characteristic parameter values of the magnetic encoder meet the evaluation conditions of the magnetic encoder characteristic parameters corresponding to the non-fault state, it is determined that each magnetic sensitive element in the magnetic absolute encoder is in a non-fault state. The evaluation conditions of the magnetic encoder characteristic parameters include: normalized amplitude deviation evaluation condition, residual DC offset evaluation condition, Lissajous figure roundness evaluation condition, and channel gain consistency evaluation condition.
6. The method according to claim 1, characterized in that, The magnetic absolute encoder includes 12 magnetic sensitive elements and 14 pairs of non-uniform pole pitch magnets. The 12 magnetic sensitive elements are evenly arranged above the magnets, covering a complete mechanical circumference. The 14 pairs of non-uniform pole pitch magnets include one first characteristic pole pair and 13 second characteristic pole pairs. The circumferential dividing angles of the 14 pole pairs along the circumference are 48°, 72°, 96°, 120°, 144°, 168°, 192°, 216°, 240°, 264°, 288°, 312°, 336°, and 360°, respectively. The magnetic absolute position value of the magnetic absolute encoder is obtained in the following manner: Obtain the calibrated magnetic encoder signal corresponding to the magnetic sensitive element that is in a non-faulty state among the various magnetic sensitive elements of the magnetic absolute encoder; Based on the current calibrated magnetic encoder signal corresponding to the magnetic sensor that is in a non-faulty state among the various magnetic sensor elements, a multi-dimensional measurement vector is obtained; The multidimensional measurement vector is matched with a pre-stored mechanical angle lookup table to obtain the coarse absolute position of the magnetic absolute encoder. The magnetic pole pair where each magnetic sensitive element is located is determined based on the coarse absolute position of the magnetic encoder; Based on the magnetic coding signals corresponding to the two adjacent magnetic sensitive elements located within the second characteristic magnetic pole, the fine electrical angle within the period of the second characteristic magnetic pole pair is calculated. The magnetic absolute position value is obtained based on the fine electrical angle and the coarse absolute position of the magnetic encoder.
7. The method according to claim 6, characterized in that, The process of obtaining the magnetic absolute position value based on the fine electrical angle and the coarse absolute position of the magnetic encoder includes: Based on the coarse absolute position, the magnetic reference position is determined according to the preset characteristic pole pair unit angle range; The magnetic reference position and the data mapped to the characteristic pole pair unit angle range are added together to obtain the summation result; The magnetic absolute position value is obtained based on the summation result.
8. The method according to claim 4 or 5, characterized in that, The non-fault state also includes qualified and alarm states, and the method further includes: when the magnetic sensitive element in the magnetic absolute encoder or the photosensitive element in the optical incremental encoder is in an alarm state, outputting a warning message.
9. The method according to claim 8, characterized in that, The evaluation conditions for magnetic coding characteristic parameters corresponding to the non-fault state include the evaluation conditions for magnetic coding characteristic parameters corresponding to the qualified state and the evaluation conditions for magnetic coding characteristic parameters corresponding to the alarm state. Furthermore, the magnetic sensitive element is determined to be in the alarm state by the following method: when the actual characteristic parameter value of the magnetic encoder of the magnetic sensitive element meets the evaluation condition of the magnetic encoder characteristic parameter corresponding to the alarm state, the magnetic sensitive element is determined to be in the alarm state. The photosensitive element is determined to be in the alarm state by the following method: when the actual optical encoding characteristic parameter value of the photosensitive element meets the optical encoding characteristic parameter evaluation condition corresponding to the alarm state, the photosensitive element is determined to be in the alarm state.
10. An absolute value encoding system for an optical-magnetic encoder, characterized in that, The device includes an optical incremental encoder and a magnetic absolute encoder, a processing unit and a storage unit, wherein the storage unit stores a computer program / instruction, causing the processing unit to execute the absolute encoding method of the optical-magnetic encoder according to the stored computer program / instruction as described in any one of claims 1 to 9.
11. A computer program product, characterized in that, It includes a computer program / instruction, which, when executed by a processor in the encoder system, implements the absolute value encoding method of the optical-magnetic encoder as described in any one of claims 1 to 9.