Angular displacement sensor, angle measurement method, and motor

Abstract

The present disclosure relates to an angular displacement sensor, an angle measurement method, and a motor. The angular displacement sensor includes: a circuit board provided with a processing circuit and an excitation circuit; a precise measurement module including a rotor and a stator disposed opposite to each other, the rotor being located between the stator and the circuit board; a collection electrode and an excitation electrode are provided on a side of the rotor facing the stator, a coupling electrode and a sensitive electrode electrically connected to the coupling electrode are provided on a side of the stator facing the rotor, the excitation electrode is excited by an electrical signal from the excitation circuit and is coupled with the coupling electrode so that the sensitive electrode generates an electrical signal, and a capacitor is formed between the collection electrode and the sensitive electrode; a rough measurement module includes a photosensitive element and a light source, one of the photosensitive element and the light source is disposed on the circuit board, and the other is disposed on the stator, and through holes are provided on the rotor and the circuit board respectively; the processing circuit is configured to obtain the absolute rotation angle of the rotor according to the number of light intensity pulses detected by the photosensitive element and the capacitance value of the capacitor formed by the collection electrode and the sensitive electrode.

Description

Technical Field

[0001] The present disclosure relates to the field of electromechanical technologies, and particularly to an angular displacement sensor, an angle measurement method, and an electric motor. Background Art

[0002] Angular displacement sensors are widely used, and the accuracy requirements span a wide range, from low-end civilian pan-tilt heads, mid-range industrial robots, to shipborne weapons with higher requirements. Various mechanical systems have put forward higher and higher requirements for angular displacement sensors. The demand for angular displacement sensors with small volume and low power consumption is also increasing. Summary of the Invention

[0003] The present disclosure provides an angular displacement sensor, an angle measurement method, and an electric motor to solve the deficiencies in the related technologies.

[0004] According to the first aspect of the embodiments of the present disclosure, an angular displacement sensor is provided, including:

[0005] A circuit board, which is provided with a processing circuit and an excitation circuit;

[0006] A precise measurement module, the precise measurement module includes a rotor and a stator arranged opposite to each other, and the rotor is located between the stator and the circuit board; on one side of the rotor facing the stator, there are a collection electrode and an excitation electrode, on one side of the stator facing the rotor, there are a coupling electrode and a sensitive electrode electrically connected to the coupling electrode, the excitation electrode is excited by an electrical signal from the excitation circuit and is coupled with the coupling electrode to cause the sensitive electrode to generate an electrical signal, and a capacitor is formed between the collection electrode and the sensitive electrode;

[0007] A rough measurement module, the rough measurement module includes a photosensitive element and a light source, one of the photosensitive element and the light source is arranged on the circuit board, and the other is arranged on the stator, and the rotor and the circuit board are respectively provided with light passing holes;

[0008] The processing circuit is configured to obtain the absolute rotation angle of the rotor according to the number of light intensity pulses detected by the photosensitive element and the capacitance value of the capacitor formed between the collection electrode and the sensitive electrode.

[0009] Optionally, the rotor and the stator are coaxially arranged annular structures; when the angular displacement sensor is in the initial position, the photosensitive element, the light source, and the light passing hole are arranged along the axial direction of the rotor.

[0010] Optionally, in the radial direction of the rotor, the light passing hole provided on the rotor is located outside the collection electrode and the excitation electrode.

[0011] Optionally, the light passing hole is an arc hole coaxially arranged with the rotor;

[0012] In the radial direction of the rotor, the radial width of the arc-shaped hole is 1 / 6 - 1 / 4 of the radial width of the acquisition electrode.

[0013] Optionally, a plurality of the acquisition electrodes are arranged along the circumferential direction of the rotor and are divided into N cycles, each cycle includes M acquisition electrodes, and in the clockwise direction, the acquisition electrodes with the same sorting in the N cycles are electrically connected as a group; the M acquisition electrodes in any one cycle are electrically connected to the output port of the rotor, and the output port is electrically connected to the processing circuit.

[0014] Optionally, the rotor includes:

[0015] An electrode layer, the electrode layer includes the acquisition electrode and the excitation electrode;

[0016] A first shielding layer;

[0017] A second shielding layer;

[0018] A signal interconnection layer, the signal interconnection layer is located between the first shielding layer and the second shielding layer, the first shielding layer is located between the signal interconnection layer and the electrode layer, the signal interconnection layer includes M wires, and the M wires are electrically connected to the M acquisition electrodes in each cycle in a one-to-one correspondence;

[0019] Wherein, a ceramic substrate is provided between adjacent two of the electrode layer, the first shielding layer, the signal interconnection layer and the second shielding layer.

[0020] Optionally, each acquisition electrode includes an acquisition area and an interconnection area electrically connected to the acquisition area, the interconnection area extends radially inwards relative to the acquisition area, in the circumferential direction of the rotor, the width of the interconnection area is smaller than the width of the acquisition area, and the M interconnection areas in each cycle are electrically connected to the M wires in a one-to-one correspondence.

[0021] Optionally, the sensitive electrode includes a plurality of electrode sheets arranged along the circumferential direction of the stator, adjacent electrode sheets are electrically connected, and each electrode sheet includes a radially outer edge and a radially inner edge symmetrically arranged, and the radially outer edge is arranged in the shape of the first half cycle of a sine curve;

[0022] At the initial position of the angular displacement sensor, each electrode sheet is arranged opposite to the M acquisition electrodes in the same cycle, and the number of electrode sheets is equal to the number of cycles of the acquisition electrodes.

[0023] According to a second aspect of the embodiments of the present disclosure, there is provided an angle measurement method, which is applied to the angular displacement sensor described in any one of the above, and the measurement method includes:

[0024] Obtaining the capacitance value of the capacitance formed between the acquisition electrode and the sensitive electrode;

[0025] Obtain the number of times the light intensity pulse is collected by the photosensitive element;

[0026] Calculate the rotation angle of the rotor relative to the stator according to the capacitance value and the number of times of the light intensity pulse.

[0027] According to a third aspect of the embodiments of the present disclosure, a motor is provided, including the angular displacement sensor described in any one of the above.

[0028] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0029] As can be seen from the above embodiments, the processing circuit and the excitation circuit in the present disclosure are designed on the same board, which is beneficial to the miniaturization of the angular displacement sensor. The rough measurement module uses a light source and a photosensitive element in cooperation, which is beneficial to reducing the power consumption of the angular displacement sensor and realizing a miniaturized and low-power angular displacement sensor.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings here are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure and used together with the specification to explain the principles of the present disclosure.

[0032] Figure 1 is a cross-sectional schematic diagram of an angular displacement sensor shown according to an exemplary embodiment.

[0033] Figure 2 is a schematic diagram of one side of the rotor facing the stator shown according to an exemplary embodiment.

[0034] Figure 3 is a schematic diagram of one side of the stator facing the rotor shown according to an exemplary embodiment.

[0035] Figure 4 is a schematic diagram of the measurement principle of an angular displacement sensor shown according to an exemplary embodiment.

[0036] Figure 5 is a cross-sectional schematic diagram of a rotor shown according to an exemplary embodiment.

[0037] Figure 6 is a schematic diagram of the electrical connection between the acquisition pole piece and the signal interconnection layer shown according to an exemplary embodiment.

[0038] Figure 7 is a flowchart of an angle measurement method shown according to an exemplary embodiment. DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0040] The terms used in the present disclosure are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0041] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0042] Figure 1 is a cross-sectional schematic diagram of an angular displacement sensor shown according to an exemplary embodiment. As Figure 1 shown, the angular displacement sensor includes a circuit board 1, a precise measurement module 2, and a rough measurement module 3. Among them, the circuit board 1 may include a board body 11, a processing circuit 12, and an excitation circuit 13. The processing circuit 12 and the excitation circuit 13 are both disposed on the same board body 11, that is, they can be integrated on the circuit board 1 for a co-board design, which can greatly reduce the volume of the angular displacement sensor, is beneficial to the miniaturization of the angular displacement sensor, and makes layout space for other components of an electronic device equipped with the angular displacement sensor, such as other components of a small electromechanical rotation system. The precise measurement module 2 includes a rotor 21 and a stator 22 disposed opposite to each other. The rotor 21 and the stator 22 can both be arranged in a circular ring plate-like structure, and the rotor 21 and the stator 22 are coaxially arranged. The rotor 21 is located between the stator 22 and the circuit board 1. Thus, the inner cavities of the rotor 21 and the stator 22 can be used to install other mechanical parts or electronic devices of the device to which the angular displacement sensor belongs. For example, the angular displacement sensor can be applied to a motor system, and the inner cavities of the rotor 21 and the stator 22 can be used to assemble related parts of the motor system, such as a conductive slip ring of the motor system.

[0043] As shown Figure 2 In the figure, in order to realize signal acquisition and signal transmission, a collection electrode 211 and an excitation electrode 212 are provided on one side of the rotor 21 facing the stator 22. As shown Figure 3 In the figure, a coupling electrode 221 and a sensitive electrode 222 are provided on one side of the stator 22 facing the rotor 21. The sensitive electrode 222 is electrically connected to the coupling electrode 221. The excitation electrode 212 is excited by an electrical signal from the excitation circuit 13 and is coupled to the coupling electrode 221 so that the sensitive electrode 222 generates an electrical signal. A capacitor is formed between the collection electrode 211 and the sensitive electrode 222.

[0044] The rough measurement module 3 includes a photosensitive element 31 and a light source 32. The photosensitive element 31 is arranged on the circuit board 1, that is, the photosensitive element 31 is electrically connected to the board body 11 of the circuit board 1. The light source 32 is fixedly arranged on the stator 22, and light passing holes 4 are respectively arranged on the rotor 21 and the stator 22. In this way, when the angular displacement sensor is at the initial position and the light source 32, the light passing hole 4 and the photosensitive element 31 are aligned in the axial direction of the rotor 21, the photosensitive element 31 can detect the light emitted by the light source 32. It can be understood that both the photosensitive element 31 and the light passing hole 4 rotate with the rotor 21, the light source 32 is fixed relative to the stator 22, and every time the rotor 21 rotates one circle relative to the stator 22, the photosensitive element 31 can detect the light emitted by the light source 32 once, forming a light intensity pulse related to the angle. Accordingly, it can be determined whether the rotor 21 rotates back to the initial position. Therefore, the number of turns of the rotor 21 rotating relative to the stator 22 can be determined by the number of light intensity pulses detected by the photosensitive element 31. In some other embodiments, it may also be that the light source 32 is arranged on the circuit board 1, that is, the light source 32 is electrically connected to the board body 11 of the circuit board 1, and the photosensitive element 31 is fixedly arranged on the stator 22. The present disclosure does not limit this. Of course, in order to simplify the angle calculation, the angular displacement sensor can be reset to the initial position after each angle measurement, that is, the same initial position is used as the zero point of the absolute rotation angle each time.

[0045] The processing circuit 12 can be used to obtain the absolute rotation angle of the rotor 21 relative to the stator 22 according to the number of light intensity pulses detected by the photosensitive element 31 and the capacitance value of the capacitor formed between the acquisition electrode 211 and the sensitive electrode 222. The processing circuit 12 can include an angle acquisition module and a coarse-fine coupled angle calculation module. The capacitance value and the number of light intensity pulses are acquired through the angle acquisition module, and the absolute rotation angle is calculated through the coarse-fine coupled angle calculation module, improving the angle measurement resolution and accuracy. Moreover, the coarse measurement module uses a low-power photosensitive element and a low-power visible light source, and adopts a low-power circuit design, which helps to reduce the system power consumption. Based on the angle coarse measurement based on light intensity and the capacitance-type angle fine measurement scheme, based on the initial angle obtained by the coarse-fine coupled calculation and the angle increment obtained by the angle fine measurement module, the accumulation output is used to obtain the absolute angle measurement value in real time, improving the angle measurement resolution and accuracy.

[0046] The light source can include an LED light source, further reducing the power consumption of the angular displacement sensor. The photosensitive element 31 uses a dedicated low-power visible light sensitive chip. The height of the entire angular displacement sensor system is less than or equal to 1.3 mm (including the heights of the stator 22, rotor 21, sensitive element 31 and the coupling air gap height), and the inner diameter size and outer diameter size can be determined according to the requirements of the equipment to which it belongs.

[0047] In some embodiments, in the radial direction of the rotor 21, the light through hole provided on the rotor 21 is located outside the acquisition electrode 211 and the excitation electrode 212 to avoid the influence of the setting of the light through hole on the area requirements of the acquisition electrode 211 and the excitation electrode 212. The excitation electrode 212 can be located inside the acquisition electrode 211. The acquisition electrode 211 can be a circular ring structure, and the excitation electrode 212 can be a circular plate structure or a circular ring structure.

[0048] In some embodiments, the light through hole 4 of the rotor 21 is an arc hole coaxially arranged with the rotor 21, and in the radial direction of the rotor 21, the radial width of the arc hole is 1 / 6 - 1 / 4 of the radial width of the acquisition electrode 211. For example, the radial width of the arc hole is 1 / 5 of the radial width of the acquisition electrode 211, occupying a very small volume, so that a larger space can be saved for the acquisition electrode 211 and the excitation electrode 212 when the diameter of the rotor 21 is certain.

[0049] In each of the above embodiments, a plurality of acquisition electrodes 211 of the rotor 21 are arranged along the circumferential direction of the rotor 21 and can be divided into N periods. Each period includes M acquisition electrodes. In the clockwise direction, the acquisition electrodes with the same sorting in the N periods are electrically connected as a group. The M acquisition electrodes 211 in any one period are electrically connected to the output port of the rotor 21, and this output port is electrically connected to the processing circuit 12. For example, the rotor 21 is provided with 64 acquisition electrodes, which are subdivided into 16 periods, and each period includes 4 acquisition electrodes. In the clockwise direction, the first acquisition electrodes 211 in each period are interconnected, the second acquisition electrodes 211 in each period are interconnected, the third acquisition electrodes 211 in each period are interconnected, and the fourth acquisition electrodes 211 in each period are interconnected, and finally four output capacitances are obtained.

[0050] For example, as Figure 4 shown, the four output capacitances include a fine measurement sin+ signal, a fine measurement sin- signal, a fine measurement cos+ signal, and a fine measurement cos- signal. According to the capacitance coupling principle, the magnitude of the capacitance formed between the acquisition electrode 211 and the sensitive electrode 222 is proportional to the acquisition voltage of the acquisition electrode 211. Therefore, the fine measurement sin+ signal, the fine measurement sin- signal, the fine measurement cos+ signal, and the fine measurement cos- signal can be capacitively demodulated through their respective corresponding conditioning circuits C / V, so as to output four output voltages. The four output voltages are subjected to R / D conversion to obtain a fine measurement angle, and this fine measurement angle can be input to the coarse-fine coupling angle calculation module to combine the coarse measurement result of the coarse measurement module to obtain the absolute rotation angle of the rotor 21.

[0051] Among them, the coupling electrode 221 includes a plurality of electrode sheets. The number of electrode sheets of the coupling electrode 221 is equal to the number of periods formed by the acquisition electrodes 211. The number of electrode sheets can be defined as the number of pole pairs of the fine measurement module. The higher the number of pole pairs within a certain size range, the better the averaging effect of the circumferential direction angle measurement error and the higher the angle detection accuracy. Considering factors such as accuracy, resolution, and manufacturing error comprehensively, the number of pole pairs of the fine measurement module can be determined. Designing the coupling area of the stator and rotor of the fine measurement module to be maximized within a limited size range helps to improve the sensitivity of angle detection.

[0052] The rotor 21 of the fine measurement module 2 can be manufactured based on printed circuit board technology, such as Figure 5As shown, the rotor 21 includes an electrode layer 213, a first shielding layer 214, a signal interconnection layer 215, and a second shielding layer 216. Among them, the electrode layer 213 includes a collection electrode 211 and an excitation electrode 212. The signal interconnection layer 215 is located between the first shielding layer 214 and the second shielding layer 216, and the first shielding layer 214 is located between the signal interconnection layer 215 and the electrode layer 213. That is, the electrode layer 213, the first shielding layer 214, the signal interconnection layer 215, and the second shielding layer 216 are sequentially stacked in the direction of the rotor 21 away from the stator 22. The signal interconnection layer 215 includes M wires 217, and the M wires 217 are electrically connected to the M collection electrodes 211 of each period one by one, so as to realize the scheme that the collection electrodes with the same sorting in N periods are electrically connected as a group.

[0053] Among them, a ceramic substrate is provided between adjacent two layers of the electrode layer 213, the first shielding layer 214, the signal interconnection layer 215, and the second shielding layer 216. The utilization of the ceramic substrate has higher processing accuracy than the conventional dielectric substrate. Therefore, it is beneficial to improve the angle measurement accuracy of the fine measurement module 2 configured with the ceramic substrate. The first layer and the third layer of the rotor 21 in the direction pointing to the stator 22 are both shielding layers, which can reduce the influence of signal coupling and external electromagnetic environment changes on the detection output. The stator 22 can also be manufactured by a circuit board process. The coupling electrodes 221 and the sensitive electrodes 222 of the stator 22, as well as the collection electrodes 211 and the excitation electrodes 212 of the rotor 21, all adopt the process of filling vias and then electroplating gold on the surface, and no other surface treatment is performed on the electrode surface, reducing the capacitance output change caused by the change of the dielectric distribution on the coupling surface of the stator and the rotor, and improving the angle measurement accuracy.

[0054] As Figure 6 shown, each collection electrode 211 includes a collection area 2111 and an interconnection area 2112 electrically connected to the collection area 2111. The interconnection area 2112 extends radially inward relative to the collection area 2111. In the circumferential direction of the rotor 21, the width of the interconnection area 2112 is smaller than the width of the collection area 2111. The M interconnection areas 2112 of each period are electrically connected to the M wires one by one. Based on this, compared with the scheme where the collection area 2111 covers the M wires 217, since the width of the interconnection area 2112 is reduced, in the axial direction of the rotor 21, the overlapping area between the collection electrode 211 and the M wires is reduced, reducing the signal coupling between different paths, and the parasitic capacitance between the wire and the collection electrode 211 can be reduced, improving the accuracy of angle fine measurement.

[0055] In some embodiments, the sensitive electrode 222 includes a plurality of electrode pieces arranged along the circumferential direction of the stator 22. Adjacent electrode pieces are electrically connected. Each electrode piece includes a radially outer edge 2221 and a radially inner edge 2222 symmetrically arranged. The radially outer edge 2221 is arranged in the shape of the first half cycle of a sine curve, asFigure 3 As shown in the figure; at the initial position of the angular displacement sensor, each electrode plate is disposed opposite to M acquisition electrodes 211 in the same period, and the number of coupling electrode plates is equal to the number of periods of the acquisition electrodes 211. Figure 6 The positions of the black dots in the figure represent the positions where the interconnection area 2112 is electrically connected to the corresponding wire through metallization holes.

[0056] Based on the technical solution of the present disclosure, as Figure 7 shown, the present disclosure also provides an angle measurement method, which is applied to the angular displacement sensor described in any one of the above embodiments. The measurement method includes the following steps:

[0057] In step 701, obtain the capacitance value of the capacitance formed between the acquisition electrode 211 and the sensitive electrode 222.

[0058] In step 702, obtain the number of times the photosensitive element 31 collects light intensity pulses.

[0059] In step 703, calculate the rotation angle of the rotor relative to the stator according to the capacitance value and the number of light intensity pulses.

[0060] In this embodiment, a sinusoidal voltage with stable frequency and amplitude can be applied to the excitation electrode 212 of the rotor 21 located in the fine measurement module 2. Through capacitive coupling, a voltage of the same frequency acts on the coupling electrode 221 of the stator 22. The coupling electrode 221 is connected to the sensitive electrode 222, and the sensitive electrode 221 in the form of a sinusoidal petal forms a sensitive capacitance with the four-channel acquisition electrodes 211 on the rotor 21. When the rotor 21 of the fine measurement module 2 has an angular change relative to the stator 22, the four capacitance values change simultaneously. The capacitance demodulation output voltage is realized through the demodulation circuit, and then the relative angular information of the stator and rotor is obtained through R / D conversion. When the stator and rotor of the fine measurement module rotate relative to each other until the light source 32 is directly above the light through hole, the visible light is sensitized by the photosensitive element 31 to form a light intensity pulse related to the angle. When the stator 22 and the rotor 21 rotate relative to each other, the processing circuit 12 simultaneously reads the light intensity and the relative angular information of the stator 22 and the rotor 21, and performs coarse and fine coupling calculation based on the angular range covered by the peak light intensity to obtain the initial angle. Based on the initial angle and whether the fine measurement relative rotation angle crosses the initial angular position, continuously judge and accumulate the relative rotation angle of the stator 22 and the rotor 21 on the basis of the initial angle to output the absolute angle.

[0061] Based on the technical solution of the present disclosure, a motor is also provided. The motor includes the angular displacement sensor described in any one of the foregoing embodiments. Utilizing the miniaturization of the angular displacement sensor is beneficial to the structural compactness inside the motor. Moreover, the inner cavities of the rotor 21 and the stator 22 of the angular displacement sensor can also be used to accommodate relevant parts of the motor, which is beneficial to the miniaturization of the motor.

[0062] Other embodiments of the present disclosure will be readily apparent to those skilled in the art upon consideration of the specification and practice of the disclosure herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed herein. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

[0063] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. An angular displacement sensor, characterized in that: include: A circuit board, wherein the circuit board is provided with a processing circuit and an excitation circuit; A precision measurement module, the precision measurement module comprises a rotor and a stator arranged opposite to each other, the rotor is located between the stator and the circuit board; a collection electrode and an excitation electrode are provided on the side of the rotor facing the stator, a coupling electrode and a sensitive electrode electrically connected to the coupling electrode are provided on the side of the stator facing the rotor, the excitation electrode is excited by an electrical signal from the excitation circuit, and is coupled with the coupling electrode so that the sensitive electrode generates an electrical signal, and a capacitor is formed between the collection electrode and the sensitive electrode; A rough measurement module, the rough measurement module comprising a photosensitive element and a light source, one of the photosensitive element and the light source is arranged on the circuit board, and the other is arranged on the stator, and the rotor and the circuit board are respectively provided with light holes; The processing circuit is used to obtain the absolute rotation angle of the rotor according to the number of light intensity pulses detected by the photosensitive element and the capacitance value of the capacitor formed by the collection electrode and the sensitive electrode.

2. The angular displacement sensor according to claim 1, characterized in that: The rotor and the stator are coaxially arranged annular structures; when the angular displacement sensor is in an initial position, the photosensitive element, the light source and the light-through hole are arranged along the axial direction of the rotor.

3. The angular displacement sensor according to claim 1, characterized in that: In the radial direction of the rotor, the light-through hole provided in the rotor is located outside the collection electrode and the excitation electrode.

4. The angular displacement sensor according to claim 1, characterized in that: The light-through hole arranged on the rotor is a circular arc hole arranged coaxially with the rotor; In the radial direction of the rotor, the radial width of the arc hole is 1 / 6-1 / 4 of the radial width of the collecting electrode.

5. The angular displacement sensor according to claim 1, characterized in that: The plurality of collecting electrodes are arranged along the circumference of the rotor and are divided into N periods, each period includes M collecting electrodes, and in the clockwise direction, the collecting electrodes of the same order in the N periods are electrically connected as a group; the M collecting electrodes of any period are electrically connected to the output port of the rotor, and the output port is electrically connected to the processing circuit.

6. The angular displacement sensor according to claim 5, characterized in that: The rotor comprises: An electrode layer, wherein the electrode layer includes the collection electrode and the excitation electrode; First shielding layer; Second shielding layer; A signal interconnection layer, the signal interconnection layer is located between the first shielding layer and the second shielding layer, the first shielding layer is located between the signal interconnection layer and the electrode layer, the signal interconnection layer includes M wires, and the M wires are electrically connected to the M collection electrodes of each period in a one-to-one correspondence; Wherein, a ceramic substrate is arranged between two adjacent layers among the electrode layer, the first shielding layer, the signal interconnection layer and the second shielding layer.

7. The angular displacement sensor according to claim 6, characterized in that: Each of the collection electrodes comprises a collection area and an interconnection area electrically connected to the collection area. The interconnection area extends radially inwardly of the rotor relative to the collection area. In the circumferential direction of the rotor, the width of the interconnection area is smaller than the width of the collection area. The M interconnection areas in each period are electrically connected to the M wires in a one-to-one correspondence.

8. The angular displacement sensor according to claim 7, characterized in that: The sensitive electrode comprises a plurality of electrode sheets arranged along the circumference of the stator, adjacent electrode sheets are electrically connected, each electrode sheet comprises a symmetrically arranged radial outer edge and a radial inner edge, and the radial outer edge is arranged in the shape of the first half period of a sine curve; At the initial position of the angular displacement sensor, each electrode sheet is arranged opposite to M collection electrodes of the same period, and the number of the electrode sheets is equal to the number of periods of the collection electrodes.

9. An angle measurement method, characterized in that: The angular displacement sensor applied to any one of claims 1 to 8, wherein the measuring method comprises: Obtaining the capacitance value of the capacitor formed between the collection electrode and the sensitive electrode; Obtaining the number of times the photosensitive element collects light intensity pulses; The rotation angle of the rotor relative to the stator is calculated according to the capacitance value and the number of the light intensity pulses.

10. A motor, characterized in that: Comprising the angular displacement sensor as claimed in any one of claims 1-8.

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