Absolute angle detection system, method and storage medium

Abstract

The application discloses an absolute rotation angle detection system and method and a storage medium, and is used for absolute rotation angle detection of a rotating shaft. The method comprises the following steps: a shaft field modulation surface is arranged on the axial surface of the rotating shaft or the surface of a transition structure which rotates synchronously with the rotating shaft, and the shaft field modulation surface is provided with a field coupling feature; a field detection unit is used for sensing a physical field signal which is emitted after being modulated by the field coupling feature; a signal processing unit is in communication connection with the field detection unit, and calibration parameters are pre-stored in the signal processing unit; and the signal processing unit is configured to output the current single-turn absolute rotation angle of the rotating shaft based on the physical field signal which is output in real time by the field detection unit and the calibration parameters. The detection system directly calculates the absolute rotation angle from the field signal, so that the system has a high-frequency dynamic response capability while maintaining high resolution, and the incremental cumulative error and the risk of pulse loss are completely eliminated.

Description

Technical Field

[0001] This invention relates to the field of rotation angle detection technology, and in particular to an absolute rotation angle detection system, method and storage medium. Background Technology

[0002] In modern industrial automation, robot joint control, high-precision CNC machine tools, and servo motors, the detection of the rotation angle of a rotating shaft is a core component for achieving precise position and speed closed-loop control. Currently, mainstream angle detection devices (such as photoelectric encoders and magnetic encoders) mainly rely on attaching an independent, separate encoder disk (such as a glass grating code disk or a multi-pole magnetic ring) to the rotating shaft being measured.

[0003] Traditional high-precision absolute or incremental encoders typically operate on an architecture based on periodic gratings / textures combined with electronic subdivision. Specifically, this involves precisely etching periodically distributed transparent / opaque grating lines (or periodic magnetic poles) onto a separate encoder disk. Periodic signals are then read by sensors, and electronic subdivision algorithms are used to improve resolution. However, this traditional architecture faces the following insurmountable drawbacks in practical applications: First, in the traditional periodic grating + subdivision architecture, the system's angle output update rate (bandwidth) is limited by the electronic subdivision factor. Typically, the angle update rate is approximately equal to the underlying signal sampling rate divided by the subdivision factor. This means that in order to achieve higher angular resolution, the subdivision factor or grating density must be increased exponentially. This directly leads to the system's inability to output accurate angle data in real time under high-speed rotation or high-dynamic scenarios, making it impossible to balance high resolution and high dynamic response.

[0004] Secondly, traditional solutions heavily rely on the physical precision of the separate, independent code disk. During assembly, eccentricity, tilting, and axial clearance fluctuations inevitably occur between the code disk and the rotating shaft. These mechanical geometric errors directly translate into angular measurement errors and are difficult to completely compensate for using software algorithms. Furthermore, accommodating the independent code disk and its associated two-dimensional imaging array or multi-channel reading head often requires a large radial space, making it difficult to meet the extremely compact requirements of modern equipment for joint or shaft-end structures. Summary of the Invention

[0005] The purpose of this invention is to provide an absolute corner detection system, method, and storage medium that can break free from the dependence on traditional split-type periodic code disks, overcome the strong coupling constraint between bandwidth and resolution, and reduce the sensitivity to mechanical assembly tolerances in order to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides an absolute rotation angle detection system based on spatial continuous field modulation for detecting the absolute rotation angle of a rotating shaft, comprising: A field modulation surface is provided on the axial surface of the rotating shaft or on the transition structure surface that rotates synchronously with the rotating shaft. The field modulation surface is a physical surface that is continuously distributed circumferentially and is configured with field coupling characteristics that are continuously varied along the circumferential direction and are distributed non-periodically as a whole. A field detection unit is disposed on the periphery of the following field modulation surface and has a physical gap with the following field modulation surface. The field detection unit is used to sense the physical field signal emitted after being modulated by the field coupling feature. A signal processing unit is communicatively connected to the field detection unit. The signal processing unit has pre-stored calibration parameters, which record a globally unique mapping relationship between the physical field signal and the single-turn absolute rotation angle within a calibration angle range. The signal processing unit is configured to output the current single-turn absolute rotation angle of the rotating shaft based on the physical field signal output in real time by the field detection unit and the calibration parameters.

[0007] Preferably, it is formed by the variation of any one or more physical parameters among the following continuously varying circumferentially changing optical reflectivity, optical transmittance, magnetic permeability, spatial magnetic field distribution, dielectric constant, electrical conductivity, or surface micro-geometric profile on the said axial field modulation surface.

[0008] Preferably, the physical field signal is an optical signal; The field detection unit includes a light emitting device and a photodetector; The light emitting device is used to emit a light beam toward the axial field modulation surface; The field coupling characteristics are formed by optical reflectivity or optical transmittance that varies continuously along the circumference, so as to modulate the beam non-periodicly. The photodetector is used to receive reflected or transmitted light modulated by the field coupling characteristics and convert it into an electrical signal that reflects changes in beam intensity or spatial light field distribution.

[0009] Preferably, the physical field signal is a magnetic field signal; The field detection unit includes an active magnetic field generating component and a magnetic sensing element; The active magnetic field generating component is used to generate an initial magnetic field for the axial field modulation surface; The field coupling characteristics are formed by a permeability or permanent magnet polarization distribution that is continuously varied circumferentially along the axial field modulation surface. The magnetic sensing element is used to sense the magnetic field modulated by the continuous change of the permeability, or to directly sense the change of the spatial magnetic field generated by the rotation of the permanent magnet polarization distribution, and output the corresponding electrical signal.

[0010] Preferably, the physical field signal is an electric field signal; The field detection unit includes a capacitor plate array and a capacitor detection circuit. The capacitor plate array is used to directionally emit an electric field toward the follow-axis field modulation surface. The field coupling feature is formed by the continuously varying dielectric constant or micro-geometric profile of the axial field modulation surface, so as to continuously change the capacitive coupling between the axial field modulation surface and the capacitor plate array when the rotation axis rotates. The capacitance detection circuit is electrically connected to the capacitor plate array and is used to detect changes in the capacitance coupling in real time and output corresponding electrical signals.

[0011] Preferably, the physical field signal is a vortex-generated signal of an alternating electromagnetic field; The field detection unit includes an excitation coil and a detection coil; The excitation coil is used to emit an alternating magnetic field to induce eddy currents in the metal conductor of the field modulation surface. The field coupling characteristic is formed by the continuously varying conductivity on the axial field modulation surface, so as to change the eddy current loss inside the conductor and the reaction field to the alternating magnetic field when the rotating shaft rotates. The detection coil is used to sense the amplitude or phase change caused by the reaction field and output the corresponding electrical signal.

[0012] Preferably, the signal processing unit further includes a data lookup table pre-written in a non-volatile memory, wherein the calibration parameters are located in the data lookup table; the signal processing unit is configured to retrieve the data lookup table during operation to obtain the single-turn absolute rotation angle.

[0013] Preferably, the signal processing unit further includes a feature extraction module, which is configured to amplify, filter and convert the analog electrical signal output by the field detection unit in sequence, and extract a dimension-reduced feature vector for mapping solution. The globally unique mapping relationship between the physical field signal and the single-cycle absolute rotation angle is expressed as a functional or lookup table correspondence between the dimensionality-reduced feature vector and the single-cycle absolute rotation angle.

[0014] The present invention also provides an absolute rotation angle detection method based on spatial continuous field modulation for detecting the absolute rotation angle of a rotating shaft, comprising: By utilizing the field coupling characteristics that rotate synchronously with the rotation axis, the physical field is spatially continuously modulated; wherein, the field coupling characteristics are configured to change continuously along the circumference and have an overall aperiodic distribution; The physical field signal, after being non-periodicly modulated by the field coupling characteristics, is acquired in real time by the field detection unit, and the physical field signal is... The feature vector representing the current spatial physical field state is extracted from the physical field signal, and the feature vector is mapped and solved by calling the pre-acquired calibration parameters to output the current single-turn absolute rotation angle of the rotation axis; wherein, the calibration parameters represent the globally unique mapping relationship between the feature vector and the single-turn absolute rotation angle at any given angle.

[0015] Preferably, the field coupling characteristics are formed by the variation of any one of the following physical parameters that are continuously varied along the circumference: light reflectivity, light transmittance, magnetic permeability, spatial magnetic field distribution, dielectric constant, electrical conductivity, or surface micro-geometric profile.

[0016] This invention also discloses an absolute angle detection system, which includes: One or more processors; Memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the absolute angle detection method as described above.

[0017] The present invention also discloses a computer-readable storage medium comprising a computer program that can be executed by a processor to perform the absolute angle detection method as described above.

[0018] Compared with existing technologies, the absolute rotation angle detection system provided by the above technical solution completely eliminates the need for traditional bulky and high-cost independent code disks by directly configuring the overall non-periodic field coupling characteristics on the surface of the rotating shaft or synchronous transition structure. This not only significantly reduces the radial volume of the system to achieve extreme compactness, but also effectively absorbs mechanical assembly errors such as eccentricity and tilt through calibration mapping. More importantly, this invention utilizes the combination of spatially continuous non-periodic physical field modulation and a pre-stored globally unique mapping relationship to achieve direct calculation from the field signal to the absolute rotation angle. This architecture breaks through the physical bottleneck of strong coupling between resolution and dynamic bandwidth caused by traditional periodic gratings combined with electronic subdivision, enabling the system to maintain high resolution while possessing extremely high high-frequency dynamic response capability; moreover, the system inherently possesses power-on absolute position output characteristics, completely eliminating incremental accumulation errors and the risk of pulse loss. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the absolute angle detection system in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the signal processing principle of the absolute angle detection system in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram illustrating the calibration principle of the physical field signal-rotation angle in an embodiment of the present invention.

[0022] Figure 4 This is a structural diagram of the detection system in this invention, where the physical field signal is an optical signal.

[0023] Figure 5 for Figure 4 Longitudinal section view.

[0024] Figure 6 for Figure 5 Enlarged view of part P in the middle.

[0025] Figure 7 This is a three-dimensional structural diagram of the fixing block in an embodiment of the present invention.

[0026] Figure 8 , Figure 9 These are two circumferential unfolded diagrams of the following embodiments of the present invention: circumferential development of the field modulation surface. Detailed Implementation

[0027] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0028] In the drive nodes of industrial joints, CNC machine tools, servo motors, and various robotic arms, high-precision detection of the absolute angle of the rotating axis is the foundation for achieving precise closed-loop position control.

[0029] This embodiment provides an absolute rotation angle detection system based on spatial continuous field modulation, such as... Figure 1 and Figure 2 It mainly includes a follow-axis field modulation surface 10, a field detection unit 2, and a signal processing unit 3.

[0030] The axial field modulation surface 10 is set on the axial surface of the rotating shaft 1 being measured, or fixed to the surface of a transition structure that rotates synchronously with the rotating shaft 1.

[0031] The axial field modulation surface 10 is a continuously circumferentially distributed physical surface on which field coupling features that vary continuously along the circumference and are distributed aperiodically as a whole are configured.

[0032] Unlike the regularly arranged transparent / opaque etched lines on traditional independent code disks, the field coupling characteristics of this embodiment do not have a repeatable periodic pattern within the entire circle (360 degrees), which is like giving the rotating shaft 1 a continuously gradually changing "physical fingerprint".

[0033] The field detection unit 2 is disposed on the periphery of the follow-axis field modulation surface 10, maintaining a non-contact physical gap with the follow-axis field modulation surface 10. The size of this physical gap is set according to the type of physical field used and the mechanical assembly tolerance zone, for example, between tens of micrometers and several millimeters.

[0034] The field detection unit 2 is used to sense the physical field signal emitted after being modulated by the field coupling feature.

[0035] When the rotating shaft 1 drives the field modulation surface 10 to rotate continuously, the physical field state at the location of the stationary field detection unit 2 will undergo continuous non-periodic distortion or intensity fluctuation, thereby outputting a physical field signal carrying angular position information.

[0036] The signal processing unit 3 maintains a communication connection with the field detection unit 2. At the hardware level, the signal processing unit 3 can be a processor chip such as a microcontroller (MCU), a digital signal processor (DSP), or a field-programmable gate array (FPGA).

[0037] The signal processing unit 3 has pre-stored calibration parameters. These calibration parameters record a globally unique mapping relationship between the physical field signal output by the field detection unit 2 and the absolute rotation angle of a single rotation within a calibration angle range (typically 0-360 degrees per rotation). Figure 3 .

[0038] In this embodiment, since the field coupling characteristics are distributed non-periodically, each tiny angular position of the rotating shaft 1 within a single revolution will generate a physical field signal with unique characteristics at the field detection unit 2.

[0039] During the manufacturing process, a high-precision reference stage is used to perform a full rotation cycle test, recording the pairing data of the actual angle and the corresponding field signal (i.e., characteristic quantity), generating calibration parameters, and writing them into a non-volatile memory. In actual operation, the signal processing unit 3 receives the signal output by the field detection unit 2 in real time and calls the pre-stored calibration parameters to directly perform mapping calculations.

[0040] By adopting the above structure and processing logic, since the rotation angle calculation no longer relies on the accumulation and counting of pulses, the system can directly look up or calculate the absolute rotation angle of a single revolution by reading the current physical field signal at the moment of power-on. It naturally possesses the ability to acquire absolute position and does not require a homing operation, fundamentally eliminating the step loss or pulse accumulation errors that are prone to occur in incremental detection when operating at high speeds or under electromagnetic interference. At the same time, by directly integrating the features onto the surface of the shaft, the traditional separate encoder disk and its complex locking mechanism are eliminated, greatly reducing the radial volume and rotational inertia of the system and significantly improving the compactness of the device end.

[0041] The field coupling characteristics are specifically formed by changing certain physical parameters that are continuously distributed circumferentially on the axial field modulation surface 10. Specifically, these physical parameters include any one or more combinations of light reflectivity, light transmittance, magnetic permeability, spatial magnetic field distribution, dielectric constant, conductivity, or surface micro-geometric profile.

[0042] For example, in implementation scenarios employing variations in surface micro-geometric contours, a continuously curved surface with a non-periodic gradual change in depth or slope can be machined on the surface of the rotating shaft 1 using precision CNC machining or 3D printing technology. When the detection field scans through this area, the scattering angle or coupling strength of its physical field signal will continuously change with the surface contour.

[0043] In scenarios employing variations in light reflectivity or light transmittance, continuous patterns with non-periodic gradients in color depth, light transmittance, or reflectivity can be formed on the surface of transitional structures through in-mold decoration (IMD), continuous laser marking, or variable thickness coating processes.

[0044] In scenarios involving variations in magnetic permeability, this can be achieved by non-uniformly doping soft magnetic materials into a non-magnetic matrix or by altering the thickness distribution of the axial magnetic coating.

[0045] Those skilled in the art will understand that it is not only possible to use a single physical parameter variation; under complex operating conditions, multiple parameters can be combined. For example, on the surface of the rotating shaft 1, a gradual change in light reflectivity can be created by laser marking, and a gradual change in micro-profile can be created by the undulations of the substrate material. Together, these two elements constitute a higher-dimensional aperiodic field coupling feature.

[0046] This method of flexibly customizing the distribution of physical parameters through various manufacturing processes enables the detection system to break free from dependence on specific high-cost processing equipment (such as high-precision lithography machines), effectively reducing the cost of large-scale production.

[0047] like Figures 4 to 6 The field detection unit 2 includes a light emitting device 20 and a photodetector 21. The light emitting device 20 (e.g., an infrared LED or VCSEL laser diode with a center wavelength of 870 nm) emits a beam of light in a directional manner toward the follow-axis field modulation surface 10.

[0048] Correspondingly, the field coupling characteristics on the axial field modulation surface 10 are formed by the optical reflectivity or optical transmittance that varies continuously along the circumferential direction of the surface of the rotation axis 1.

[0049] Specifically, such as Figures 6 to 9 The rotating shaft 1 has a fixed block 11 at its end. The side of the fixed block 11 is divided into upper and lower parts, namely the first part 110 and the second part 111. The first part 110 and the second part 111 have different light emissivity, and the boundary line 112 between the first part 110 and the second part 111 has a continuous non-periodic variation characteristic, such as a non-repeating periodic wavy line (e.g. Figure 9 ), or the plane formed by the dividing line is inclined to the centerline of the rotation axis 1 (e.g. Figure 8 ).

[0050] Taking the reflective configuration as an example, when a motor shaft 1 with a nominal diameter of 20mm rotates at high speed, the constant light beam illuminating it will be absorbed and reflected non-periodically because its end side is covered with a coating whose light reflectivity changes continuously and gradually along the circumference according to a preset non-periodic mathematical model.

[0051] The photodetector 21 (e.g., a photodiode array or a high-bandwidth integrated photosensitive chip) is disposed on the reflected or transmitted light path to receive the light signal modulated by the above-mentioned field coupling characteristics and convert it into an analog electrical signal that reflects the overall intensity fluctuation of the light beam or the change in the spatial light field distribution.

[0052] In harsh industrial environments with heavy oil contamination, high dust levels, or high temperatures (such as joints in construction machinery and mining motors), optical detection is highly susceptible to failure due to lens contamination or optical path obstruction. Therefore, in another preferred embodiment, the present invention provides a detection system based on magnetic field coupling. In this implementation scenario, the physical field signal utilized is a magnetic field signal.

[0053] In this embodiment, the field detection unit 2 includes an active magnetic field generating component (such as a PCB planar coil or a small permanent magnet ring) and a magnetic sensing element (such as a Hall sensor array, an AMR anisotropic magnetoresistive or GMR giant magnetoresistive sensor). With the assistance of this field detection unit 2, the field coupling characteristics on the axial field modulation surface 10 are changed to be composed of a permeability or permanent magnet polarization distribution that changes continuously along the circumference.

[0054] Taking a scenario utilizing changes in magnetic permeability as an example, a modulation ring, composed of a soft magnetic material (such as permalloy or silicon steel) and a non-magnetic material (such as epoxy resin), can be fitted onto the end of the rotating shaft 1. The modulation ring has a smooth surface, but the radial width or axial depth of the soft magnetic material inside it exhibits a non-periodic, continuous variation along the circumference. An active magnetic field generating component excites an initial spatial magnetic field into the modulation ring. As the rotating shaft 1 rotates, the continuously changing magnetic permeability boundary continuously and non-periodically alters the concentration and orientation of local spatial magnetic field lines. A magnetic sensing element positioned at a physical gap (e.g., 0.5 mm) above the modulation ring can detect this magnetic field, modulated and distorted by the continuous change in magnetic permeability, in real time and output a voltage signal of corresponding intensity.

[0055] If a scenario with permanent magnet polarization distribution is used, the active magnetic field generating component can be omitted. A permanent magnet with a non-periodic and continuous change in magnetic pole strength or magnetization angle along the circumference can be directly filled into the surface of the rotating shaft 1. The magnetic sensing element can directly sense the absolute change of the spatial magnetic field with the rotation angle.

[0056] Through the above structure, without changing the underlying architecture logic of non-periodic continuous modulation combined with mapping and solving, the system switches the observation medium to a magnetic field with extremely strong penetrating power. This allows the entire sensing system to output stable and reliable characteristic signals to the signal processing unit 3 even if it is completely covered by non-magnetic dirt (such as dust, engine oil, mud and water), which greatly extends the engineering adaptability and service life of the absolute angle detection system under harsh working conditions.

[0057] For specific application scenarios involving strong external magnetic field interference or requiring extremely low power consumption detection, this invention also provides an absolute rotation angle detection configuration based on electric field signals. In this configuration, the axial field modulation surface 10 is also disposed on the outer surface of the rotation shaft 1, and the physical field signal is specifically manifested as an electric field signal.

[0058] The field detection unit 2 includes a capacitor plate array and a capacitance detection circuit. The capacitor plate array is arranged in an arc shape or in segments around the outer periphery of the rotating shaft 1, maintaining a predetermined radial physical gap (e.g., 0.2 mm to 0.5 mm) with the outer surface. Under the excitation of the capacitance detection circuit, the capacitor plate array directionally emits an alternating electric field toward the field modulation surface 10.

[0059] To achieve continuous non-periodic modulation of the spatial electric field, the field coupling characteristics are formed by the dielectric constant or micro-geometric profile that varies continuously on the field modulation surface 10.

[0060] For example, an insulating dielectric layer with a non-periodic, continuously undulating thickness can be applied to the outer surface of the metal rotating shaft 1; or a network of micro-grooves with continuously varying depths can be directly machined onto the side surface of the rotating shaft 1. When the rotating shaft 1 rotates, the distribution of dielectric material or the effective distance in the side region facing the capacitor plates changes continuously, resulting in non-periodic, continuous fluctuations in the capacitive coupling between the shaft field modulation surface 10 and the capacitor plate array.

[0061] The capacitance detection circuit is electrically connected to the capacitor plate array, detecting minute changes in the capacitance coupling (typically on the order of picofarads or femtofarads) in real time and outputting the corresponding electrical signal. In this radial detection configuration, the radial runout during the rotation of shaft 1 inevitably causes slight fluctuations in the physical gap between the capacitor plates and the outer surface. However, since this system employs a factory calibration mechanism based on the assembled machine, this parasitic capacitance change caused by radial eccentric displacement, which is strongly correlated with the rotation period, is considered part of the system's inherent "physical fingerprint." This change is directly absorbed and fitted by the pre-stored calibration parameters, thereby eliminating the error caused by eccentricity in angle mapping at the signal processing backend and ensuring computational accuracy.

[0062] Under extreme conditions such as heavy oil contamination and metal dust, the aforementioned capacitor or optical configurations may face the risk of failure. Therefore, this embodiment further proposes a detection system based on vortex-generated signals to adapt to such harsh environments.

[0063] In this implementation scenario, the field detection unit 2 includes an excitation coil and a detection coil, both of which are fixed radially to the outer side of the rotating shaft 1.

[0064] The excitation coil is connected to a high-frequency oscillation circuit (e.g., an excitation frequency of 1MHz to 5MHz) to emit an alternating magnetic field to the follow-axis field modulation surface 10. In this case, the carrier of the follow-axis field modulation surface 10 must contain a metallic conductor material.

[0065] Its field coupling characteristics are formed by the continuously varying conductivity on the field modulation surface 10. In actual manufacturing, the local conductivity of the outer surface of the rotating shaft 1 can be varied aperiodically by ion implantation, local heat treatment, or non-periodic embedding of metal alloy strips with different conductivity on the substrate surface.

[0066] When the alternating magnetic field excited by the excitation coil penetrates the outer surface of the rotating shaft 1, eddy currents are induced inside the metal conductor. As the rotating shaft 1 rotates, the continuously changing conductivity characteristics cause eddy current losses inside the conductor and the reaction magnetic field generated by these eddy currents to change continuously. The detection coil is used to sense the amplitude or phase change of the total spatial magnetic field caused by this reaction magnetic field and convert it into an analog voltage signal output.

[0067] By detecting the eddy current field, it can not only completely penetrate the obstruction of non-conductive media (such as engine oil, mud, and plastic shells), but its high-frequency characteristics also give the system extremely high dynamic response capabilities. Similarly, the assembly gap fluctuation deviation caused by radial arrangement is compensated by the back-end signal processing unit 3 based on calibration data.

[0068] In another embodiment, the signal processing unit 3 contains a non-volatile memory (such as Flash or EEPROM) in which a data lookup table (LUT) is pre-written. The calibration parameters at the factory are in the form of the aforementioned data lookup table. During the factory calibration stage, the rotating shaft 1 under test is assembled onto a reference test bench, and the physical field signal characteristics at different absolute rotation angles within one revolution are recorded, forming key-value pairs and stored in the lookup table.

[0069] During system operation, signal processing unit 3 is configured to obtain the absolute rotation angle per turn by retrieving a data lookup table.

[0070] Specifically, when the on-site detection unit 2 outputs a real-time electrical signal at a sampling rate of, for example, 20kHz, the signal processing unit 3 directly uses the feature value of the electrical signal as an address or index to perform a high-speed addressing in the lookup table. If the real-time acquired feature value is located between two discrete nodes in the lookup table, a first-order or higher-order interpolation algorithm can be executed through a hardware multiplier-accumulator to obtain a continuous high-resolution angle output.

[0071] Because a direct mapping path of lookup table and interpolation is used, the angle output update rate is mainly limited by the field sampling rate of the front end and the memory access time of the processor. Since the time complexity of the lookup table operation is extremely low (approximately O(1)), the system can maintain high resolution while the angle update rate is approximately equal to the sampling rate (e.g., reaching tens of thousands of hertz). This completely eliminates the physical limitation of traditional periodic grating schemes that must rely on electronic subdivision circuits to wait for pulse accumulation, giving the motor control system extremely high mid-to-high frequency dynamic response capability.

[0072] In practical engineering applications, to improve anti-interference capability and signal uniqueness, the field detection unit 2 typically includes multiple independent receiving channels (e.g., four optical emitting devices 20 and four photodetector devices 21 distributed circumferentially). Directly mapping multiple analog signals using a high-precision lookup table would lead to lookup table dimension explosion, consuming enormous storage space. Therefore, this embodiment optimizes the signal front-end processing mechanism: The signal processing unit 3 further integrates a feature extraction module. In the hardware data flow, the original multi-channel analog electrical signal output by the field detection unit 2 first enters the feature extraction module, and is then amplified by a preamplifier circuit, filtered by a low-pass or band-pass filter to remove high-frequency noise, and then discretized into a digital quantity by an analog-to-digital converter (ADC).

[0073] Furthermore, the feature extraction module is configured at the software or logic gate level to perform dimensionality reduction processing on the aforementioned high-dimensional digital signals, extracting dimensionality-reduced feature vectors for mapping calculations. Specific dimensionality reduction methods may include principal component analysis (PCA), multi-channel differential scaling, or vector normalization. For example, the absolute voltage values ​​of the four channels can be converted into two-dimensional coordinates reflecting relative intensity.

[0074] After the above feature extraction, the globally unique mapping relationship between the aforementioned physical field signal and the single-cycle absolute rotation angle is visualized as a function or lookup table correspondence between the dimensionality-reduced feature vector and the single-cycle absolute rotation angle.

[0075] By reducing the data dimensionality, the required non-volatile memory capacity is significantly reduced, allowing calibration parameters to be easily embedded in inexpensive microcontrollers. Furthermore, multi-channel differential or proportional operations can effectively offset common-mode interference (such as overall system temperature drift or emitter light decay), significantly improving the system's stability and robustness during long-term service.

[0076] In summary, this invention discloses an absolute rotation angle detection system based on spatial continuous field modulation. The system architecture completely abandons the traditional independent periodic split code disk that relies on high-precision engraving or magnetic poles. It directly utilizes the overall non-periodic distribution of field coupling characteristics on the outer surface of the rotating shaft 1, combined with radial non-contact field detection on the stationary side, to characterize the angle position by obtaining the continuous "physical fingerprint" of the rotating shaft 1.

[0077] This system not only achieves comprehensive compatibility with various physical field mechanisms such as optics, magnetic fields, electric fields, and eddy currents, endowing the sensor with high environmental adaptability, but also brings multiple technical advantages at the system level. By abandoning the pulse counting mechanism, the system can output a unique absolute rotation angle through calibration mapping upon power-up, eliminating the risks of incremental accumulation and missed steps; the solution path of single-point sampling and lookup table mapping breaks the mutual constraint between bandwidth and resolution, achieving excellent high-frequency dynamic response; more importantly, the angle measurement feature is integrated into the surface of the rotating shaft 1, and the clearance fluctuation error caused by mechanical assembly eccentricity is absorbed by using global calibration data, which greatly relaxes the mechanical assembly tolerance requirements. While reducing the radial and axial volume of the whole machine, it significantly reduces the implementation cost of precision angle measurement, providing a brand-new solution for the miniaturization and high reliability control of industrial servo and robot joints.

[0078] This invention also discloses another absolute corner detection system, which includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors. The programs include instructions for performing the absolute corner detection method in the above embodiments. The processor may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute the relevant programs to implement the functions required by the modules in the absolute corner detection system of this application, or to execute the absolute corner detection method of the above embodiments of this application.

[0079] This invention also discloses a computer-readable storage medium comprising a computer program that can be executed by a processor to perform the absolute corner detection method of the above embodiments. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state disks (SSDs).

[0080] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the absolute angle detection method of the above embodiments.

[0081] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. An absolute rotation angle detection system for detecting the absolute rotation angle of a rotating shaft, characterized in that, include: A field modulation surface is provided on the axial surface of the rotating shaft or on the transition structure surface that rotates synchronously with the rotating shaft. The field modulation surface is a physical surface that is continuously distributed circumferentially and is configured with field coupling characteristics that are continuously varied along the circumferential direction and are distributed non-periodically as a whole. A field detection unit is disposed on the periphery of the following field modulation surface and has a physical gap with the following field modulation surface. The field detection unit is used to sense the physical field signal emitted after being modulated by the field coupling feature. A signal processing unit is communicatively connected to the field detection unit. The signal processing unit has pre-stored calibration parameters, which record a globally unique mapping relationship between the physical field signal and the single-turn absolute rotation angle within a calibration angle range. The signal processing unit is configured to output the current single-turn absolute rotation angle of the rotating shaft based on the physical field signal output in real time by the field detection unit and the calibration parameters.

2. The absolute angle detection system according to claim 1, characterized in that, The field coupling characteristic is formed by the variation of any one or more physical parameters among the continuously changing light reflectivity, light transmittance, magnetic permeability, spatial magnetic field distribution, dielectric constant, conductivity, or surface micro-geometric profile on the axial field modulation surface.

3. The absolute angle detection system according to claim 1, characterized in that, The physical field signal is an optical signal; The field detection unit includes a light emitting device and a photodetector; The light emitting device is used to emit a light beam toward the axial field modulation surface; The field coupling characteristics are formed by optical reflectivity or optical transmittance that varies continuously along the circumference, so as to modulate the beam non-periodicly. The photodetector is used to receive reflected or transmitted light modulated by the field coupling characteristics and convert it into an electrical signal that reflects changes in beam intensity or spatial light field distribution.

4. The absolute angle detection system according to claim 1, characterized in that, The physical field signal is a magnetic field signal; The field detection unit includes an active magnetic field generating component and a magnetic sensing element; The active magnetic field generating component is used to generate an initial magnetic field for the axial field modulation surface; The field coupling characteristics are formed by a permeability or permanent magnet polarization distribution that is continuously varied circumferentially along the axial field modulation surface. The magnetic sensing element is used to sense the magnetic field modulated by the continuous change of the permeability, or to directly sense the change of the spatial magnetic field generated by the rotation of the permanent magnet polarization distribution, and output the corresponding electrical signal.

5. The absolute angle detection system according to claim 1, characterized in that, The physical field signal is an electric field signal; The field detection unit includes a capacitor plate array and a capacitor detection circuit. The capacitor plate array is used to directionally emit an electric field toward the follow-axis field modulation surface. The field coupling feature is formed by the continuously varying dielectric constant or micro-geometric profile of the axial field modulation surface, so as to continuously change the capacitive coupling between the axial field modulation surface and the capacitor plate array when the rotation axis rotates. The capacitance detection circuit is electrically connected to the capacitor plate array and is used to detect changes in the capacitance coupling in real time and output corresponding electrical signals.

6. The absolute angle detection system according to claim 1, characterized in that, The physical field signal is a vortex generation signal of an alternating electromagnetic field; The field detection unit includes an excitation coil and a detection coil; The excitation coil is used to emit an alternating magnetic field to induce eddy currents in the metal conductor of the field modulation surface. The field coupling characteristic is formed by the continuously varying conductivity on the axial field modulation surface, so as to change the eddy current loss inside the conductor and the reaction field to the alternating magnetic field when the rotating shaft rotates. The detection coil is used to sense the amplitude or phase change caused by the reaction field and output the corresponding electrical signal.

7. The absolute angle detection system according to claim 1, characterized in that, The signal processing unit further includes a data lookup table pre-written in a non-volatile memory, wherein the calibration parameters are located in the data lookup table; the signal processing unit is configured to retrieve the data lookup table during operation to obtain the single-turn absolute rotation angle.

8. The absolute angle detection system according to claim 1, characterized in that, The signal processing unit also includes a feature extraction module, which is configured to amplify, filter and convert the analog electrical signal output by the field detection unit in sequence, and extract the dimension-reduced feature vector for mapping solution. The globally unique mapping relationship between the physical field signal and the single-cycle absolute rotation angle is expressed as a functional or lookup table correspondence between the dimensionality-reduced feature vector and the single-cycle absolute rotation angle.

9. An absolute rotation angle detection method for detecting the absolute rotation angle of a rotating shaft, characterized in that, include: By utilizing the field coupling characteristics that rotate synchronously with the rotation axis, the physical field is spatially continuously modulated; wherein, the field coupling characteristics are configured to change continuously along the circumference and have an overall aperiodic distribution; The physical field signal, after being non-periodicly modulated by the field coupling characteristics, is acquired in real time by the field detection unit, and the physical field signal is... The feature vector representing the current spatial physical field state is extracted from the physical field signal, and the feature vector is mapped and solved by calling the pre-acquired calibration parameters to output the current single-turn absolute rotation angle of the rotation axis; wherein, the calibration parameters represent the globally unique mapping relationship between the feature vector and the single-turn absolute rotation angle at any given angle.

10. The absolute angle detection method according to claim 9, characterized in that, The field coupling characteristics are formed by the variation of any one of the following physical parameters that are continuously varied along the circumference: light reflectivity, light transmittance, magnetic permeability, spatial magnetic field distribution, dielectric constant, electrical conductivity, or surface micro-geometric profile.

11. An absolute angle detection system, characterized in that, include: One or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the absolute angle detection method as described in any one of claims 1 to 2.

12. A computer-readable storage medium, characterized in that, Includes a computer program, which can be executed by a processor to perform the absolute angle detection method as described in any one of claims 1 to 2.

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