Absolute spatial multi-dimensional rotation angle displacement sensor

Abstract

An absolute spatial multi-dimensional rotation angle displacement sensor, comprising a spherical shell-shaped stator base (1) and a spherical rotor base (2) located in a spherical shell. Six excitation units are evenly arranged on the inner wall of the spherical shell, and eight sensing units are evenly arranged on the rotor base (2). Each excitation unit is composed of an even number of excitation electrode sheets (11), and a gap is reserved between adjacent excitation electrode sheets (11). A stator support shaft (12) is mounted on the outer surface of the stator base (1). Aside from the excitation unit corresponding to the stator support shaft (12), through holes running through from inside to outside are formed in the stator base (1) at positions corresponding to the remaining five excitation units. The axes of the four through holes are perpendicular to the stator support shaft (12). At least two adjacent through holes among the four through holes are communicated with each other by means of a connecting groove, and the connecting groove and the communicated through holes together form a rotatable region. The rotor support shaft (22) extends out through the rotatable region. The stator support shaft (12) can readily rotate within an angle corresponding to the rotatable region for measurement, significantly increasing the angle measurement range, thereby greatly expanding the application scenario of the sensor.

Description

Absolute space multi-dimensional rotary angle displacement sensor TECHNICAL FIELD

[0001] The present application relates to time grating sensing technology, and in particular to an absolute space multi-dimensional rotary angle displacement sensor, belonging to the field of precise angle displacement measurement. BACKGROUND

[0002] In the fields of industrial automation, robotics, aerospace, etc., it is crucial to accurately measure the spatial multi-dimensional rotary angle displacement of an object. Traditional angle displacement sensors, such as photoelectric encoders and rotary transformers, can mostly only measure single-dimensional angle displacement, making it difficult to meet the demand for simultaneous measurement of spatial multi-dimensional angle displacement. There are also some multi-dimensional angle displacement measurement schemes in the prior art, such as: a combination scheme based on multiple single-axis sensors: multiple single-axis sensors are combined in a specific manner to achieve multi-dimensional angle displacement measurement. However, this scheme has problems such as large volume, complex structure, high cost, etc. A scheme based on visual measurement: a camera is used to capture the image of a target object, and an image processing algorithm is used to calculate the angle displacement. However, this scheme is easily disturbed by environmental light, relies on zero point reset or external reference calibration, and cannot directly obtain absolute angle displacement information after power failure or sudden disturbance, making it difficult to guarantee measurement accuracy and real-time performance. As can be seen, the existing spatial multi-dimensional rotary angle displacement sensors have problems such as large volume, complex structure, high cost, susceptibility to interference, low measurement accuracy, etc., making it difficult to meet the demand of practical applications. Therefore, it is of great significance to develop an absolute space multi-dimensional rotary angle displacement sensor with simple structure, low cost, strong anti-interference ability, and high measurement accuracy.

[0003] In recent years, a time grating sensor has been developed in China, which uses clock pulses as a displacement measurement reference. By applying orthogonal excitation signals to a flat capacitive array, a uniform motion alternating electric field is constructed, thereby realizing the conversion of spatial displacement to a time reference, and a nanometer circle time grating sensor with a whole circle accuracy of ±0.06" has been developed. However, the current nanometer time grating sensor can only measure planar angle displacement and cannot measure multi-dimensional angle displacement in spherical space.

[0004] In view of this, the applicant has proposed and applied for a patent for "a spherical multidimensional rotation angle measurement grating sensor and its installation structure", application number 2025100261809. The sensor stator base is spherical, and the rotor base is spherical and located inside the spherical shell of the stator base. A gap is left between the surface of the rotor base and the inner surface of the stator base, so that the rotor base is suspended and concentric with the stator base. Six excitation units of the same shape and size are evenly distributed on the inner surface of the stator base. The center of the six excitation units is located at the center of the six faces of a cube externally tangent to the inner surface of the stator base. Eight sensing units of the same shape and size are evenly distributed on the surface of the rotor base. The eight sensing units are symmetrically distributed on the eight quadrants of a spatial rectangular coordinate system with the center of the rotor base as the origin. This structure can achieve high-precision multi-dimensional rotation angle measurement in spherical space. It is simple in structure, thoroughly decoupled, and has strong anti-interference ability. However, its angle measurement range is usually within 40°, which is limited and cannot meet the requirements for large angle measurement, thus limiting its application scenarios. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, the purpose of this invention is to provide an absolute spatial multidimensional rotational angular displacement sensor. This invention can realize absolute measurement of multidimensional rotational angular displacement in spherical space, and has a large angle measurement range, simple structure, easy installation of leads, and is easy to implement.

[0006] The technical solution of this invention is implemented as follows:

[0007] An absolute spatial multidimensional rotational angular displacement sensor includes a stator base and a rotor base. An excitation unit is disposed on the stator base, and a sensing unit is disposed on the rotor base. The stator base is spherical, and the rotor base is spherical and located within the stator base's spherical shell. A gap exists between the surface of the rotor base and the inner surface of the stator base, allowing the rotor base to be suspended and concentric with the stator base. The excitation units consist of six identical units of the same shape and size, evenly spaced on the inner surface of the stator base. The centers of the six excitation units are located at the centers of the six faces of a cube externally tangent to the inner surface of the stator base. The sensing units consist of eight identical units of the same shape and size, evenly spaced on the surface of the rotor base. The eight sensing units are symmetrically distributed in the eight quadrants of a spatial rectangular coordinate system with the center of the rotor base as the origin.

[0008] The stator base is provided with a stator support shaft for rotating connection with the stator drive turntable. The excitation electrode is connected to an external excitation source through a signal line penetrating the stator base housing. The rotor base is provided with a rotor support shaft for rotating connection with the rotor drive turntable. The signal line of the induction electrode is led out from the stator base through the rotor support shaft. The rotor support shaft and the stator support shaft are perpendicular to each other.

[0009] Each excitation unit consists of an even number of excitation poles, and all excitation poles in the same excitation unit are connected to the same signal line. All excitation poles in the same excitation unit are evenly distributed around the center of the excitation unit along the circumference, with gaps between adjacent excitation poles. The stator support shaft is fixedly installed on the outer surface of the stator base and at a position corresponding to the center of one of the excitation units. Except for the excitation unit corresponding to the stator support shaft, through holes are opened on the stator base at positions corresponding to the other five excitation units, and each through hole is centered relative to the corresponding excitation unit, i.e., the excitation poles are arranged around the through holes. The axes of four of the through holes are perpendicular to the stator support shaft. At least two of the four through holes are connected by connecting slots opened on the stator base, and the length direction of the connecting slots is perpendicular to the stator support shaft. Both ends of the connecting slots pass through the gaps in the excitation units at their respective ends, and the width of the connecting slots is greater than the diameter of the rotor support shaft. The connecting slots and the through holes connected by the connecting slots together form a rotatable area. The rotor support shaft extends out of the stator base through the rotatable area, and the rotation angle of the stator support shaft is limited by the rotatable area.

[0010] Furthermore, three adjacent through holes are connected by connecting grooves on the stator base to achieve an angle measurement range greater than 180°; or all four through holes are connected by connecting grooves to achieve an angle measurement range greater than 270°.

[0011] One end of the rotor support shaft is integrally formed with the surface of the rotor base and avoids the area where the sensing unit is located.

[0012] Specifically, all sensing units have the same spherical triangle outer contour shape. At the three vertices of each spherical triangle, concave arc edges are formed by cutting. Any four adjacent sensing units with arc edges facing the same vertex form a circular blank area. One end of the rotor support shaft is integrally formed with the rotor base surface through one of the circular blank areas, thereby avoiding the area where the sensing units are located.

[0013] Alternatively, all sensing units can be hollowed out at their centers, and one end of the rotor support shaft can be integrally formed with the rotor base surface through one of the hollowed-out areas to avoid the area where the sensing units are located.

[0014] Furthermore, the diameter of the rotor base is smaller than the diameter of the through hole; the width of the connecting groove is smaller than the diameter of the through hole.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention employs a fan-shaped ring excitation electrode arrangement in space orthogonally to achieve encoding around the X-axis and Y-axis in spherical space. The same sensing unit uses two adjacent sensing electrodes arranged in a differential structure to pick up signals. By summing the output signals of two adjacent sensing groups with an adder, coupling signals in non-measurement directions are filtered out. Common-mode interference is eliminated by subtracting the differential signals, thereby further improving the signal decoupling capability. The decoupling is thorough and the anti-interference capability is strong, thus realizing the absolute measurement of multidimensional angular displacement in space. Moreover, the structure is simple and easy to implement.

[0017] This invention creates a rotatable region by opening slots in the spherical shell that forms the stator substrate. Each excitation unit consists of an even number (e.g., 2, 4, or 6) of independent excitation electrodes with gaps between them. These gaps correspond to the rotatable region on the shell. In this way, when the stator support shaft drives the rotatable region to rotate, the excitation unit and the excitation electrodes will not interfere with the rotor support shaft that rotates relative to it within the rotatable region. The stator support shaft can rotate and measure within the corresponding angle of the rotatable region, significantly improving the angle measurement range and greatly expanding the application scenarios of the sensor.

[0018] In addition, the present invention provides five through holes that run through the inside and outside of the spherical shell, which facilitates the nearby lead wires of the excitation electrodes, so that the leads of all excitation electrodes do not need to be led out through the same channel, making the circuit connection more convenient. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the overall structure of the sensor in Embodiment 1 of the present invention.

[0020] Figure 2 is a schematic diagram of the stator base and rotor base in Embodiment 1 of the present invention.

[0021] Figure 3 is a schematic diagram of the excitation electrode arrangement coding in Embodiment 1 of the present invention.

[0022] Figure 4 is a schematic diagram of the induction electrode arrangement coding in Embodiment 1 of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] Referring to Figures 1-4, this invention discloses an absolute spatial multidimensional rotational angular displacement sensor, comprising a stator base 1 and a rotor base 2. An excitation unit is mounted on the stator base 1, and a sensing unit is mounted on the rotor base 2. The stator base 1 is spherical with a thickness of h. The rotor base 2 is spherical and located within the spherical shell of the stator base 1. A gap d is left between the surface of the rotor base and the inner surface of the stator base, allowing the rotor base to be suspended and concentric with the stator base.

[0025] The excitation units are six identical units of the same shape and size, evenly spaced on the inner surface of the stator base 1, and not in contact with each other. These units are designated a, b, c, d, e, and f. The centers of the six excitation units are located at the centers of the six faces of a cube externally tangent to the inner surface of the stator base. The six excitation units are symmetrical about the XOY, XOZ, and YOZ planes, respectively, meaning they are located on the coordinate axes X+, X-, Y+, Y-, Z+, and Z-, and are equidistant from the origin O. Four of the six excitation units (a, b, c, d) can be considered to rotate around the Z-axis, and four (a, e, c, f) can be considered to rotate around the X-axis. Excitation units a and c are shared excitation units for both rotation around the Z-axis and rotation around the X-axis. Of course, since the excitation units are arranged symmetrically in the X, Y, and Z directions without difference, other interpretations are also possible. For example, four excitation units can rotate around the Z-axis, and four can rotate around the Y-axis, with two of the excitation units sharing the rotation directions around the Z and Y axes; or four excitation units can rotate around the X-axis, and four can rotate around the Y-axis, with two of the excitation units sharing the rotation directions around the X and Y axes.

[0026] Referring to Figure 4, the sensing units consist of eight identical units of the same shape and size, evenly spaced and distributed on the surface of the rotor base 2, without contacting each other. These eight sensing units are designated A, B, C, D, A', B', C', and D', and are symmetrically distributed across the eight quadrants of a Cartesian coordinate system with the center of the rotor base as the origin (i.e., the rotor base 2 is divided into eight regions by XOY, XOZ, and YOZ, with each region containing a sensing electrode 21 forming a sensing unit). All eight sensing units are equidistant from the origin and are spherically symmetrical with respect to the center of the sphere. The eight sensing units are located inside a sphere composed of six excitation units, meaning the outer radius of each sensing unit is smaller than its inner radius. The spatial phase difference between any two sensing units bounded by any cross-section is 90°. The thickness of each sensing unit is h2, and the spacing between adjacent sensing units is w.

[0027] The stator base 1 is provided with a stator support shaft 12 for rotational connection with the stator drive turntable. The excitation electrode is connected to an external excitation source through a signal line passing through the stator base housing. The rotor base 2 is provided with a rotor support shaft 22 for rotational connection with the rotor drive turntable. The signal line of the induction electrode is led out from the stator base through the rotor support shaft. The rotor support shaft 22 and the stator support shaft 12 are perpendicular to each other.

[0028] Referring to Figure 3, each excitation unit of the present invention consists of an even number of excitation electrodes 11, each with a thickness of h1. All excitation electrodes in the same excitation unit are connected to the same signal line. In this embodiment, each excitation unit consists of 4 excitation electrodes 11, and there are a total of 24 excitation electrodes 11 in 6 excitation units. All excitation electrodes 11 in the same excitation unit are evenly distributed around the center of the unit along the circumference, with gaps between adjacent electrodes. The stator support shaft is fixedly installed on the outer surface of the stator substrate at a position corresponding to the center of one of the excitation units. Except for the excitation unit corresponding to the stator support shaft, through holes are provided on the stator substrate at positions corresponding to the other five excitation units, with each through hole centered relative to the corresponding excitation unit, i.e., the excitation electrodes are arranged around the through holes. In this embodiment, the through holes are circular holes with a radius of r3, which facilitates the connection of the excitation electrodes on the inner surface of the spherical shell to the external circuit leads. The axes of four through holes are perpendicular to the stator support shaft. At least two adjacent through holes are connected by connecting slots formed in the stator base, with the length of the connecting slots perpendicular to the stator support shaft. Both ends of the connecting slots pass through the gaps in the excitation units (i.e., the connecting slots do not affect the arrangement of the excitation pole pieces), and the width L of the connecting slots is greater than the diameter L1 of the rotor support shaft 22. The connecting slots and the through holes connected by the connecting slots together constitute a rotatable region. The rotor support shaft 22 extends out of the stator base 1 through the rotatable region, and the rotation angle of the stator support shaft 22 is limited by the rotatable region. In this invention, the gap width between adjacent excitation pole pieces is greater than the width of the connecting slot, and the width of the connecting slot is greater than the diameter of the rotor support shaft, to ensure that the rotor support shaft can rotate within the rotatable region.

[0029] The axis of symmetry of the rotatable region of this invention along the length of the connecting groove is also the axis of symmetry of the excitation unit at that location. The excitation electrodes constituting the excitation unit at that location are arranged half on each side of this axis of symmetry. This is why each excitation unit in this invention consists of an even number of excitation electrodes (to facilitate the arrangement of the excitation electrodes and the opening of the connecting groove). Since each excitation electrode requires wiring, the more excitation electrodes there are, the more complex the wiring becomes. Therefore, in practical design, an excitation unit can be composed of only two excitation electrodes, thus ensuring the formation of a gap, facilitating the arrangement of the excitation electrodes, and simplifying the wiring.

[0030] In this invention, all excitation electrodes 11 are tightly attached to the inner surface of the stator substrate 1, that is, the radius of the outer surface of the excitation unit is equal to the radius of the inner surface of the stator substrate. Each sensing unit is composed of a conductive metal sensing electrode 21, and the eight sensing electrodes 21 corresponding to the eight sensing units are tightly attached to the outer surface of the rotor substrate 2, and the radius of the inner surface of each sensing unit is equal to the radius of the outer surface of the rotor substrate.

[0031] In this invention, one end of the stator support shaft 12 is integrally formed with the outer surface of the stator base 1, and the other end of the stator support shaft 12 is connected to the stator drive turntable. According to the patented technology mentioned in the background section, the rotor support shaft can rotate 360°, but the stator support shaft cannot. The rotation angle of the stator support shaft is limited by the mounting holes on the surface of the stator base. During the rotation of the stator support shaft, the wall of the mounting hole where the rotor support shaft is located will encounter the rotor support shaft, thus limiting the rotation range of the stator support shaft. Therefore, this invention forms a rotatable area by creating connecting grooves on the stator base to connect the through holes. Compared to a single through hole angle, the rotatable area has a significantly increased angle range. Meanwhile, each excitation unit consists of an even number (e.g., 2, 4, 6) of independent excitation poles, with gaps between them. These gaps correspond to the rotatable areas on the housing. This way, when the stator support shaft drives the rotatable area to rotate, the excitation unit and the excitation poles will not interfere with the rotor support shaft, which rotates relative to the rotatable area. The stator support shaft can rotate and measure within the corresponding angle of the rotatable area, significantly improving the angle measurement range and greatly expanding the application scenarios of the sensor.

[0032] In addition, the present invention provides five through-holes on the spherical shell, which facilitates the nearby lead wires of the excitation electrodes, so that the leads of all excitation electrodes do not need to be led out through the same channel, making the circuit connection more convenient.

[0033] In practical implementation, three adjacent through holes are connected by creating connecting slots in the stator base, allowing for an angle measurement range greater than 180° for the stator support shaft; alternatively, all four through holes can be connected via connecting slots, achieving an angle measurement range greater than 270°. In actual measurements, considering the angle corresponding to the diameter of the through holes themselves, connecting three through holes results in an actual angle measurement range of approximately 230°, while connecting all four through holes provides a maximum angle range of 330°. The specific method for creating the connecting slots depends not only on the sensor's angle measurement range but also on the connection strength of the stator base itself after slotting, ensuring that the slotting does not affect the strength of the spherical shell. If the spherical shell material has sufficient strength, the measurement range can approach 350°.

[0034] When the rotor support shaft 22 of the present invention is installed, one end of it is integrally formed with the surface of the rotor base 2 and needs to avoid the area where the sensing unit is located. To avoid the area where the sensing unit is located, the present invention includes, but is not limited to, the following two implementation methods:

[0035] Method 1: All sensing units (sensing electrode 21) have the same spherical triangle outer contour shape. At the three vertices of each spherical triangle, concave arc edges are formed by cutting. Any four adjacent sensing units with arc edges facing the same vertex form a circular blank area. One end of the rotor support shaft 22 is integrally formed with the surface of the rotor base 2 through one of the circular blank areas, thereby avoiding the area where the sensing units are located.

[0036] Method 2: All sensing units are hollowed out in the center, and one end of the rotor support shaft 22 is integrally formed with the surface of the rotor base 2 through one of the hollowed-out areas, thereby avoiding the area where the sensing units are located.

[0037] All excitation electrodes 11 are identical fan-shaped rings. All excitation electrodes in each excitation unit form a ring with several breaks in the middle, and each break is the gap between two excitation electrodes.

[0038] The diameter of the rotor base is smaller than the diameter of the through hole; the width of the connecting groove is smaller than the diameter of the through hole. This facilitates product installation, allowing the rotor base to directly enter the spherical shell through the through hole.

[0039] Example: As shown in Figure 2, the stator base 1 and rotor base 2 are concentrically mounted with a gap d = 30cm. The radius of stator base 1 is r1 = 80cm, the radius of rotor base 2 is r2 = 50cm, and the thickness of stator base 1 is h = 1cm. Excluding the side with the stator support shaft 12, each of the other five sides of the stator base 1 has a circular hole with a radius r3 = 40cm. This circular hole facilitates the connection of the annular excitation electrode 11 on the inner surface of the stator base 1 to the external circuit leads.

[0040] As shown in Figure 3, 24 fan-shaped excitation pole pieces 11 with a thickness of h1 = 2 mm are installed on the inner surface of the stator substrate 1. Four pole pieces form one excitation unit. The four excitation units (16 excitation pole pieces 11) arranged in the four-sided space around the X-axis form the excitation phase around the X-axis; the four excitation units (16 excitation pole pieces 11) arranged in the four-sided space around the Y-axis form the excitation phase around the Y-axis. Two excitation units, with a total of eight excitation pole pieces, share the same pole pieces in both directions. The excitation phases around the X-axis and Y-axis are encoded as S1, S2, S3, and S4, respectively.

[0041] The principle of angular displacement measurement in this invention is as follows: a coupling capacitor is formed between the inductive electrode and the excitation electrode. During measurement, four sinusoidal excitation signals with sequentially different phases of 90° and equal frequency and amplitude are applied to the excitation units in the four-sided space around the X-axis and Y-axis, respectively. Each excitation unit has four fan-shaped excitation electrodes receiving the same excitation signal. The four excitation signals are represented as: U s﹢ =A m sin(ωt), U c﹢=A m cos(ωt), U s﹣ =﹣A m sin(ωt), U c﹣ =﹣A m cos(ωt), where the signal amplitude Am = 5V and the frequency f = 1 / ω = 40KHz. When the rotor base 2 rotates relative to the stator base 1, the eight induction poles 21 A, B, C, D, A', B', C', and D' generate U through electric field coupling. A U B U C U D U A' U B' U C' U D' Eight-channel induction signals.

[0042] The eight-channel induction signals are combined to obtain four-channel measurement signals: U A U B U C U D Summation is performed using an adder, U A' U B' U C' U D' By summing the signals using an adder, two traveling wave signals U are obtained respectively. Y+ and U Y- ;Change U A U A' U D U D' Summation is performed using an adder, U B U C U B' U C' By summing the signals using an adder, two traveling wave signals U are obtained respectively. X+ and U X- .

[0043] Will U X+ and U X- U Y+ and U Y- By subtracting each signal from the others, we obtain the traveling wave signal U rotating around the X-axis. X and the traveling wave signal U rotating around the Y-axis Y ;

[0044] The sinusoidal traveling wave signal U around the X-axis X and the sinusoidal traveling wave signal U around the Y-axis YAfter being shaped into a square wave by the shaping circuit, it is simultaneously sent to the FPGA for phase detection and compared with the reference square wave of the same frequency. The phase difference is represented by the number of interpolated high-frequency clock pulses. After conversion, the rotational angular displacement x of the rotor base 2 relative to the stator base 1 in the X-axis direction and the rotational angular displacement y in the Y-axis direction are obtained.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the applicant has described the present invention in detail with reference to preferred embodiments, those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An absolute spatial multidimensional rotational angular displacement sensor, comprising a stator base and a rotor base, wherein an excitation unit is disposed on the stator base and a sensing unit is disposed on the rotor base; the stator base is spherical, the rotor base is spherical and located inside the spherical shell of the stator base, and a gap is left between the surface of the rotor base and the inner surface of the stator base so that the rotor base is suspended and concentric with the stator base; the excitation unit consists of 6 identical excitation units of the same shape and size, evenly spaced on the inner surface of the stator base; the centers of the 6 excitation units are located at the centers of the six faces of a cube externally tangent to the inner surface of the stator base; the sensing unit consists of 8 identical excitation units of the same shape and size, evenly spaced on the surface of the rotor base; the 8 sensing units are symmetrically distributed in the 8 quadrants of a spatial rectangular coordinate system with the center of the rotor base as the origin; The stator base is provided with a stator support shaft for rotating connection with the stator drive turntable. The excitation electrode is connected to an external excitation source through a signal line penetrating the stator base housing. The rotor base is provided with a rotor support shaft for rotating connection with the rotor drive turntable. The signal line of the induction electrode is led out from the stator base through the rotor support shaft. The rotor support shaft and the stator support shaft are perpendicular to each other. Its features are: Each excitation unit consists of an even number of excitation poles, and all excitation poles in the same excitation unit are connected to the same signal line. All excitation poles in the same excitation unit are evenly distributed around the center of the excitation unit along the circumference, with gaps between adjacent excitation poles. The stator support shaft is fixedly installed on the outer surface of the stator base and is positioned corresponding to the center of one of the excitation units. Except for the excitation unit corresponding to the stator support shaft, through holes are opened on the stator base at positions corresponding to the other five excitation units, and each through hole is centered relative to the corresponding excitation unit, i.e., the excitation poles are arranged around the through holes. The axes of four through holes are perpendicular to the stator support shaft. At least two of the four through holes are connected by connecting slots opened on the stator base, and the length direction of the connecting slots is perpendicular to the stator support shaft. Both ends of the connecting slots pass through the gaps in the excitation units at their respective ends, and the width of the connecting slots is greater than the diameter of the rotor support shaft. The connecting slots and the through holes connected by the connecting slots together form a rotatable area. The rotor support shaft extends out of the stator base through the rotatable area, and the rotation angle of the stator support shaft is limited to the rotatable area.

2. The absolute spatial multidimensional rotational angular displacement sensor according to claim 1, characterized in that: Three of the four through holes are connected by connecting grooves on the stator base to achieve an angle measurement range of more than 180°; or all four through holes are connected by connecting grooves to achieve an angle measurement range of more than 270°.

3. The absolute spatial multidimensional rotational angular displacement sensor according to claim 1, characterized in that: One end of the rotor support shaft is integrally formed with the surface of the rotor base and avoids the area where the sensing unit is located.

4. An absolute spatial multidimensional rotational angular displacement sensor according to claim 3, characterized in that: All sensing units have the same spherical triangle shape on their outer contour. At the three vertices of each spherical triangle, concave arc edges are formed by cutting. Any four adjacent sensing units with arc edges facing the same vertex form a circular blank area. One end of the rotor support shaft is integrally formed with the rotor base surface through one of the circular blank areas, thereby avoiding the area where the sensing units are located.

5. An absolute spatial multidimensional rotational angular displacement sensor according to claim 3, characterized in that: All sensing units have a hollowed-out center, and one end of the rotor support shaft is integrally formed with the rotor base surface through one of the hollowed-out areas, thereby avoiding the area where the sensing units are located.

6. An absolute spatial multidimensional rotational angular displacement sensor according to claim 1, characterized in that: The excitation electrode is a fan-shaped ring.

7. An absolute spatial multidimensional rotational angular displacement sensor according to claim 1, characterized in that: One end of the stator support shaft is integrally formed with the outer surface of the stator substrate.

8. An absolute spatial multidimensional rotational angular displacement sensor according to claim 1, characterized in that: The diameter of the rotor base is smaller than the diameter of the through hole; the width of the connecting groove is smaller than the diameter of the through hole.

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