Sensing self-driven self-zeroing time grating angular displacement sensor

Abstract

The invention relates to a sensing self-driven self-zeroing time grating angular displacement sensor, and belongs to the technical field of sensors. Each of the stator and the rotor comprises a circular base body and electrodes distributed on the surface of the circular base body along the circumference; the motor further comprises a circular dielectric material friction layer arranged between the electrodes of the stator and the rotor, the friction layer is fixed to the surfaces of the electrodes of the stator in a pasted mode, and the electrodes of the stator periodically output current through relative rotation of the rotor relative to the stator and the friction layer. Besides, an electrode vacancy position is formed by removing any electrode in the rotor, any electrode in the stator is selected as independent output, the independent output electrode is not electrically connected with other stator electrodes, and zero-crossing judgment is achieved through low level output by the independent output electrode when the independent output electrode passes through the electrode vacancy position. The self-driven and self-zeroing time grating angular displacement sensor is realized, and the angular displacement measurement precision and resolution of the sensor can be improved.

Description

Technical Field

[0001] This invention belongs to the field of displacement sensor technology, and relates to a self-driven, self-zeroing time grating angular displacement sensor based on triboelectric nano-power generation effect and time grating precision displacement measurement technology. Background Technology

[0002] With the rise and development of the Internet of Things, the relative backwardness of high-performance sensors and the urgent need for self-driven sensors driven by the increasing number of mobile electronic devices and sensor networks have become bottlenecks restricting the intelligent development of high-end equipment in my country. Researching an angular displacement sensor that can both sense and drive itself and achieve high-precision, high-resolution displacement measurement will help promote the greening of manufacturing equipment and improve its level of intelligence.

[0003] Existing angular displacement parameter sensing mainly suffers from the following three problems: 1. Energy conversion devices can convert different forms of energy into electrical energy without the need for external power supply excitation, but they cannot achieve high-precision and high-resolution measurement performance when used for displacement sensing. 2. Existing displacement detection technologies mostly require energy to drive, which cannot meet the requirements of low power consumption or even self-driving.

[0004] 3. Incremental sensors reset a new zero point every time they are started, which cannot meet the operational requirements of machines that require absolute position control. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a time-grating angular displacement sensor that is self-driven and self-zeroing. By integrating the triboelectric nano-power generation effect and the time-grating sensor, the sensor achieves self-driven sensing while ensuring high-precision and high-resolution angular displacement measurement. At the same time, the calibration problem of the measurement zero position is solved by removing one electrode from the uniformly arranged electrodes to create a vacancy position.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A self-driven, self-zeroing time-grid angular displacement sensor includes a stator and a rotor. Both the stator and rotor include a circular substrate and electrodes distributed circumferentially on the surface of the circular substrate. The sensor also includes a circular dielectric material friction layer disposed between the electrodes of the stator and rotor. The friction layer is fixed to the surface of the stator electrodes by adhesive bonding. The stator electrodes periodically output current by the relative rotation of the rotor relative to the stator and the friction layer.

[0007] In addition, an electrode vacancy position is formed by arbitrarily removing one electrode in the rotor, and an electrode in the stator is selected as a separate output. The separate output electrode is not electrically connected to other stator electrodes. Zero crossing is achieved by the low level output by the separate output electrode when it passes through the electrode vacancy position.

[0008] Furthermore, the stator electrodes are fan-shaped annular metals, and the number is a multiple of 4. Four adjacent electrodes form an output group, and in each output group, two electrodes spaced apart form the positive and negative poles of an output pair, respectively.

[0009] Furthermore, the rotor electrode is a double sinusoidal metal electrode, with each rotor electrode corresponding to an output group in the stator.

[0010] Furthermore, the radial length of the rotor electrode is slightly less than the radial length of the stator electrode; the width of the rotor electrode is the sum of the widths of the two stator electrodes and the width of the gap between the two stator electrodes.

[0011] Furthermore, the circular bases of the rotor and stator, as well as the circular friction layer, are provided with circular holes; the circular holes in the stator base are larger than those in the rotor base.

[0012] Furthermore, when using this sensor, the rotor is fixed on the rotating shaft, and the stator is coaxial with the rotor and mounted on a fixed base. The stator and rotor are either installed close to each other or spaced a certain distance apart.

[0013] When the stator and rotor are installed in a phase-separated manner, the distance between them is 0~3 mm.

[0014] Furthermore, the electrodes of the stator and rotor are made of copper or aluminum.

[0015] Furthermore, the dielectric material is polytetrafluoroethylene, polyethylene terephthalate, or polyimide.

[0016] Furthermore, the circular base of the stator and rotor is made of insulating material.

[0017] The beneficial effects of this invention are as follows: (1) Unlike traditional time-grid angular displacement sensors that use external AC signals to drive the sensing element, this invention adds a nanomaterial friction layer between the stator and rotor of the sensor. As the rotating mechanical equipment moves, the stator and rotor rotate relative to each other, resulting in vertical separation of the friction layer and the generation of spatial displacement signal. This makes the sensor self-driving at the sensing source.

[0018] (2) Based on the theory of “space-time conversion”, the present invention can use high-frequency clock pulse counting to calculate high-resolution position information. This method gets rid of the dependence of the measurement performance on the precision mechanical grid when the triboelectric nano-power generation effect is used for angular displacement measurement, thereby greatly improving the sensor’s measurement accuracy and resolution of angular displacement.

[0019] (3) The present invention sets an electrode vacancy position on the rotor electrodes arranged along the circumference, and at the same time uses a stator electrode as a separate output. When the electrode vacancy position passes through the separate output electrode, the separate output electrode can output a low level lower than the normal output voltage to detect whether the electrode vacancy position passes through the separate output electrode and realize the zero position calibration.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a self-driven, self-zeroing time grating angular displacement sensor structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the electrical connection method of the stator electrodes; Figure 3 This is a schematic diagram of the coupling method between the stator electrodes and the rotor electrodes; Figure 4 A schematic diagram illustrating the principle of generating orthogonal signals through the triboelectric effect; Figure 5 This is a schematic diagram of the sensor's signal processing. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0023] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0024] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] To address the common problems of existing angular displacement sensors, such as dependence on precision mechanical manufacturing, power supply issues, and inconsistent zero-point operation, this invention proposes a self-driven, self-zeroing time-grating angular displacement sensor based on triboelectric nano-power generation and time-grating precision displacement measurement technology. This invention uses triboelectric nano-power generation as a medium to solve the problem of existing time-grating sensors requiring AC power for operation; it constructs a time traveling wave through a signal transmission module to achieve the measurement of spatial quantities from time quantities, solving the problem that the electrode spacing determines the measurement resolution when using triboelectric nano-power generation for displacement measurement; it integrates triboelectric nano-power generation and the time-grating sensor to achieve self-driven sensing while maintaining high precision and high resolution angular displacement measurement; and it solves the problem of zero-point calibration by removing one electrode from a uniformly arranged electrode to create a vacant position.

[0026] like Figure 1 As shown, a time-grid angular displacement sensor provided in an embodiment of the present invention is structurally composed of a stator, a rotor, and an independent friction layer.

[0027] The rotor and stator bases are discs of equal diameter, with a circular hole in the center of each disc. The circular hole in the stator base is slightly larger than the circular hole in the rotor base.

[0028] On the stator substrate, there is a ring of equally spaced fan-shaped metal electrodes as induction electrodes. The stator substrate is made of insulating material, such as resin, ceramic, or plastic, while the induction electrodes are made of copper or aluminum and can be arranged on the substrate using photolithography or PCB technology.

[0029] The number of stator electrodes is a multiple of 4. Four adjacent stator electrodes form an output group. The first and third electrodes of each output group are the positive and negative terminals of one output pair, respectively, and the second and fourth electrodes are the positive and negative terminals of another output pair, respectively. The electrodes at corresponding positions in each output group are electrically connected. Figure 2 As shown.

[0030] Correspondingly, a ring of equally spaced double sinusoidal metal electrodes is also coated on the rotor substrate, with the number being one-quarter of the number of stator electrodes. That is, each output group corresponds to one rotor electrode. The rotor electrode is formed by splicing together half a cycle of two sine lines represented in polar coordinates. The radial length of the rotor electrode is slightly smaller than the radial length of the stator electrode. In the circumferential direction, the width of the rotor electrode (corresponding sector angle) is the sum of the widths of two stator electrodes and the width of the gap between the two stator electrodes. The coupling method between the rotor electrode and the stator electrode is as follows: Figure 3 As shown.

[0031] A thin film of polymer dielectric material is attached to the stator as an independent friction layer. The dielectric material can be polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), or polyimide (Kapton), etc.

[0032] When installing the sensor, the rotor is mounted on the shaft via a coupling or directly, and the stator is mounted coaxially with the rotor on a fixed base. The stator and rotor can be installed close together or with a gap of 0 to 3 mm.

[0033] In this embodiment, to achieve the sensor's self-zeroing function, any rotor electrode is removed while maintaining the same electrode spacing, and the electrical connection between one stator electrode and the other stator electrodes is disconnected, making it a separate output. When the position of the vacant rotor electrode passes over the independently output stator electrode, this independently output stator electrode will generate a voltage level lower than normal, thus indicating that the rotor has passed the zero position. During signal processing, the output signal of this independently output stator electrode is reconnected to the remaining stator electrodes using the principle of voltage superposition to participate in displacement calculations normally.

[0034] Based on the principle of triboelectric nanogenerators, during rotor rotation, the charges on the rotor electrodes attract oppositely polarized charges in the dielectric material to the upper surface to achieve charge balance. Simultaneously, the stator electrodes compensate for charge vacancies on the lower surface of the dielectric material through charge flow. The potential generated in the electrodes is proportional to the coupling area between the rotor and stator electrodes, and the magnitude of the generated current is related to the rotor speed.

[0035] like Figure 4 As shown, taking a single loop as an example, its specific operation process is as follows: 1) When the rotor electrode enters one of the output groups of the stator from the left end, the rotor electrode is coupled only to electrode 1 in the output group. The negative charge in the friction layer is attracted by the positive charge on the rotor electrode. In order to maintain charge balance, the positive charge will move to the lower surface, causing electrode 1 to become negatively charged. A current flows from electrode 3 to electrode 1 in the external circuit. When the center line of the rotor electrode coincides with the center line of electrode 1, electrode 1 carries the most negative charge, and the current generated in the external circuit is the largest.

[0036] 2) When the rotor electrode rotates between electrode 1 and electrode 3, the positive charge on electrode 1 increases and the positive charge on electrode 3 decreases. The current on the external load also gradually decreases. When the rotor electrode moves to the middle, the charges on electrode 1 and electrode 3 reach equilibrium, and no current is generated in the external circuit at this time.

[0037] 3) When the rotor electrode is decoupled from electrode 1 and only partially overlaps with electrode 3, the surface of electrode 3 carries a negative charge, and a current flows from electrode 1 to electrode 3 in the external circuit. When the center line of the rotor electrode coincides with the center line of electrode 3, electrode 3 carries the most negative charge, and the current generated in the external circuit is the largest.

[0038] The electrodes of the two circuits in the same output group are arranged in an alternating pattern, resulting in two signals with a spatial phase difference of 90°. By sending these two spatially orthogonal signals into the signal processing module, high-precision, high-resolution measurement of angular displacement can be achieved using high-frequency pulse interpolation technology. The signal processing process is as follows: Figure 5 As shown.

[0039] This embodiment provides a specific sensor device, as described below: Using PCB technology, copper is directly applied to the substrate surface according to the drawn pattern to form the rotor and stator electrodes. Both the stator and rotor substrates are 60 mm diameter disks with 20 mm and 19 mm diameter holes respectively in the center. The size of the holes can be adjusted according to the size of the shaft.

[0040] Forty sector-shaped copper electrodes are evenly arranged on the stator substrate. Four adjacent electrodes form an output group. The electrodes that constitute the output pair in each output group are connected to the inner copper ring through wires. The copper ring is arranged on the back of the PCB substrate and connected to the wires through vias.

[0041] Ten double sinusoidal copper electrodes are uniformly arranged on the rotor substrate. The shape of the electrodes in the polar coordinate system is given by the formula... Confirmed, among which It is half the radial length of the rotor electrode, while It should be slightly smaller than the radial length of the fan-shaped annular electrode. This represents the number of rotor electrodes, which is 10 in this case. It is the radius of the center circle of the electrode, which should coincide with the center circle of the stator electrode.

[0042] A PTFE film is attached to the stator electrode as an independent friction layer.

[0043] This embodiment provides a method for installing and testing sensors on servo motors. Specifically, the motor shaft is passed through the circular hole in the center of the rotor base, the rotor is fixed to the end of the shaft, the stator is pasted on the plane of the three-axis moving stage, and the stator and rotor are ensured to be concentric and spaced about 1 mm apart by adjusting the adjusting screws of the three-axis moving stage.

[0044] A wire is led out from each of the four copper rings of the stator and connected to the data acquisition card. The signal is processed and calculated using LabVIEW software.

[0045] Furthermore, in accordance with the design principles described above, the present invention can also achieve absolute position detection by adding another ring of metal electrodes to the stator on the structure of the above embodiments. The number of output groups in the two rings of electrodes differs, that is, the number of output groups in the inner ring is... N The number of output groups in the outer ring is N+1 When the rotor rotates, it generates two sets of orthogonal but different phase sinusoidal signals, which are then sent to the signal processing module to obtain the absolute position based on the phase difference.

[0046] 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 present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A time-grid angular displacement sensor with self-driving and self-zeroing capability, characterized in that, The system includes a stator and a rotor, each comprising a circular substrate and electrodes distributed circumferentially on the surface of the circular substrate. It also includes a circular dielectric material friction layer disposed between the electrodes of the stator and rotor. The friction layer is fixed to the surface of the stator electrodes by adhesive bonding. The stator electrodes periodically output current due to the relative rotation of the rotor relative to the stator and the friction layer. An electrode vacancy is created by arbitrarily removing one electrode from the rotor. Any electrode in the stator is selected as a separate output electrode, which is not electrically connected to other stator electrodes. Zero-crossing detection is achieved by the low-level output of the separate output electrode when it passes through the electrode vacancy.

2. The time-grid angular displacement sensor according to claim 1, characterized in that, The stator electrodes are fan-shaped metal rings, and the number is a multiple of 4. Four adjacent electrodes form an output group. In each output group, two electrodes spaced apart form the positive and negative poles of an output pair, respectively.

3. The time-grid angular displacement sensor according to claim 2, characterized in that, The rotor electrode is a double sinusoidal metal electrode, and each rotor electrode corresponds to an output group in the stator.

4. The time-grid angular displacement sensor according to claim 3, characterized in that, The radial length of the rotor electrode is less than the radial length of the stator electrode; the width of the rotor electrode is the sum of the widths of the two stator electrodes and the width of the gap between the two stator electrodes.

5. The time-grid angular displacement sensor according to claim 1, characterized in that, The circular base of the rotor and stator, as well as the center of the circular friction layer, are provided with circular holes; the circular hole in the stator base is larger than the circular hole in the rotor base.

6. The time-grid angular displacement sensor according to claim 5, characterized in that, When using this sensor, the rotor is fixed on the rotating shaft, and the stator is coaxial with the rotor and installed on the fixed base. The stator and rotor are installed close to each other or at a certain distance.

7. The time-grid angular displacement sensor according to claim 6, characterized in that, When the stator and rotor are installed alternately, the spacing is 0~3 mm.

8. The time-grid angular displacement sensor according to claim 1, characterized in that, The electrodes of the stator and rotor are made of copper or aluminum.

9. The time-grid angular displacement sensor according to claim 1, characterized in that, The dielectric material is polytetrafluoroethylene, polyethylene terephthalate, or polyimide.

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