Triboelectric sensing device and power device

Abstract

The application relates to the field of tribology nanotechnology, and discloses a triboelectric sensing device and a power device, which can realize real-time monitoring of the rotating speed of a UAV and guarantee the flight safety of the UAV. The triboelectric sensing device comprises a triboelectric sensing unit, the triboelectric sensing unit comprises a stator and a rotor arranged coaxially, and the rotor can rotate relative to the stator. The stator comprises a stator disc and a triboelectric electrode pair arranged on the side of the stator disc facing the rotor, and the triboelectric electrode pair comprises a first triboelectric electrode and a second triboelectric electrode arranged along the circumference of the stator disc. The rotor comprises a rotor disc and a rolling body arranged on the rotor disc, the rotor disc is provided with a mounting hole, the rolling body is arranged in the mounting hole in a rotatable mode, the surface of the rolling body is coated with a friction dielectric material layer, and a part of the rolling body protrudes from the side of the rotor disc facing the stator disc, so that when the rotor rotates relative to the stator, a triboelectric signal is generated through friction contact between the rolling body and the triboelectric electrode pair.

Description

Technical Field

[0001] This application relates to the field of triboelectric nanogenerator technology, and in particular to a triboelectric sensing device and a power device. Background Technology

[0002] Motion control of rotary-wing drones is achieved by adjusting the differences in the rotational speed of each rotor. Each rotor is driven by an independent electrode to rotate the propeller. By precisely controlling the rotational speed and direction of each rotor, the magnitude of the thrust and lateral force generated by the propeller can be adjusted. Then, by calculating the magnitude and direction of the resultant force, precise control of the drone's flight can be achieved.

[0003] During the flight of a rotary-wing drone, if any motor stops working, the drone will lose control and be unable to fly normally. Therefore, real-time monitoring of propeller speed is a crucial aspect of ensuring the flight safety of rotary-wing drones. Currently, the commutation speed method is commonly used, indirectly detecting the motor and propeller speeds by collecting the commutation frequency of the electronic speed controller (ESC). This method cannot directly monitor the actual speed in real time. When a motor / ESC malfunctions or the power supply voltage fluctuates, the problem cannot be reported in real time, thus compromising the drone's flight safety. Utility Model Content

[0004] This application provides a triboelectric sensing device and a power device. The triboelectric sensing device can monitor the rotational speed of a rotary-wing UAV in real time, thereby ensuring the flight safety of the UAV.

[0005] In a first aspect, this application provides a triboelectric sensing device, including a triboelectric sensing unit, wherein the triboelectric sensing unit includes a stator and a rotor arranged coaxially, and the rotor is rotatable relative to the stator;

[0006] The stator includes a stator disk and a pair of friction electrodes disposed on the side of the stator disk facing the rotor. The pair of friction electrodes includes a first friction electrode and a second friction electrode arranged circumferentially along the stator disk.

[0007] The rotor includes a rotor disk and rolling elements disposed on the rotor disk. The rotor disk has a mounting hole, and the rolling elements are rotatably disposed in the mounting hole relative to the mounting hole. The surface of the rolling elements is covered with a triboelectric material layer, and a portion of the rolling elements protrudes from the side of the rotor disk facing the stator disk, so that when the rotor rotates relative to the stator, the rolling elements and the triboelectric electrode pair generate triboelectric signals through triboelectric contact.

[0008] The triboelectric sensing device provided in this application comprises a stator and a rotor. The stator is equipped with pairs of friction electrodes, and the rotor has rolling elements coated with a triboelectric dielectric material layer. When the rotor rotates relative to the stator, the rolling elements roll back and forth in contact with the first and second friction electrodes, thereby generating an electrical signal. When the triboelectric sensing device is used for monitoring the rotational speed of a UAV, the rotor disk can be connected to a motor, so that the motor can drive the rotor to rotate simultaneously with the propeller. When the UAV is in flight, the triboelectric sensing device can generate electrical signals in real time, thereby determining the real-time rotational speed of the motor and propeller, which facilitates the assessment of the UAV's flight status. Therefore, the triboelectric sensing device in this application can be used for real-time monitoring of UAV rotational speed, thereby ensuring the flight safety of the UAV.

[0009] In some possible implementations, the stator disk is provided with at least two pairs of friction electrodes, which are evenly distributed along the circumference of the stator disk.

[0010] The rotor includes at least two sets of rolling elements corresponding to the at least two pairs of friction electrodes, and the at least two sets of rolling elements are spaced apart along the circumference of the rotor disk.

[0011] The rotor disk is provided with at least two sets of mounting holes corresponding to the at least two sets of rolling elements, and each rolling element is installed in the respective mounting hole.

[0012] In some possible implementations, each set of rolling elements includes at least one of the rolling elements, which has a clearance fit with the mounting hole.

[0013] In some possible implementations, when each set of rolling elements includes multiple rolling elements, the orthographic projection of the multiple rolling elements on the projection plane is fan-shaped;

[0014] The orthographic projections of the plurality of rolling elements on the projection plane are located within the orthographic projection of the first friction electrode on the projection plane, or the orthographic projections of the plurality of rolling elements on the projection plane are located within the orthographic projection of the second friction electrode on the projection plane;

[0015] The projection plane is a plane perpendicular to the axis of the rotor disk.

[0016] In some possible implementations, the stator includes two stator disks, which are respectively disposed on both sides of the rotor;

[0017] Each of the stator disks is provided with a pair of friction electrodes on the side facing the rotor, and the pairs of friction electrodes provided on the two stator disks are symmetrically distributed with the rotor as the axis of symmetry.

[0018] The rolling element protrudes from both sides of the rotor disk, so that the rolling element generates a triboelectric signal with the friction electrode pairs on both sides respectively.

[0019] In some possible implementations, the triboelectric sensing unit further includes an annular support, the stator disk is fixedly connected to the annular support, and the rotor disk is disposed within the annular support.

[0020] In some possible implementations, the inner wall of the annular support is provided with a boss, the boss being arranged circumferentially along the annular support, and the stator disk overlapping the boss.

[0021] In some possible implementations, the annular support is provided with a positioning groove, and the stator disk is provided with a positioning part, which is embedded in the positioning groove.

[0022] In a second aspect, this application provides a power device, including a body, a power module, and a triboelectric sensing device as described in any possible embodiment of the first aspect, wherein the power module and the triboelectric sensing device are disposed on the body, and the power module is connected to the rotor of the triboelectric sensing device to drive the rotor to rotate relative to the stator.

[0023] In some possible implementations, the power unit is a rotary-wing unmanned aerial vehicle;

[0024] The machine body includes multiple arms, each arm is equipped with a propeller, and each arm is equipped with a power module and a triboelectric sensing device. The power module is used to drive the propeller to rotate relative to the arm, and the stator of the triboelectric sensing device is fixedly connected to the arm. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an overall structure of the triboelectric sensing device in an embodiment of this application;

[0026] Figure 2 This is a cross-sectional structural schematic diagram of a triboelectric sensing device in an embodiment of this application;

[0027] Figure 3 This is an exploded structural diagram of a triboelectric sensing device in an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of one structure of the stator in an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the rotor structure in one embodiment of this application;

[0030] Figure 6This is a schematic diagram of the electrical signals generated by the triboelectric sensing device in the embodiments of this application during operation.

[0031] In the picture:

[0032] 100-Stator; 110-Stator disk; 120-First friction electrode; 130-Second friction electrode; 140-Positioning part; 141-Connecting hole; 150-Fixing part; 200-Rotor; 210-Rotor disk; 220-Mounting hole; 230-Rolling element; 240-Connecting shaft; 241-Fixing hole; 300-Annular bracket; 310-Positioning groove; 320-Fixing groove; 330-Boss. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] refer to Figure 1 The triboelectric sensing device in the embodiments of this application may include a triboelectric sensing unit, which may include a stator 100, a rotor 200 and an annular support 300. The stator 100 and the rotor 200 are both connected to the annular support 300 so that the annular support 300 can support the stator 100 and the rotor 200.

[0035] refer to Figure 3 The stator 100 may include a stator disk 110 and a pair of friction electrodes disposed on the side of the stator disk 110 facing the rotor 200. The pair of friction electrodes may include a first friction electrode 120 and a second friction electrode 130 arranged circumferentially along the stator disk 110.

[0036] Please refer to the above. Figure 2 and Figure 3 The rotor 200 may include a rotor disk 210 and rolling elements 230 disposed on the rotor disk 210. The rotor disk 210 is provided with a mounting hole 220, and the rolling elements 230 are disposed within the mounting hole 220. The surface of the rolling elements 230 is covered with a triboelectric material layer. A portion of the rolling elements 230 may protrude from the side surface of the rotor disk 210 facing the stator disk 110, and the rolling elements 230 may also rotate relative to the mounting hole 220.

[0037] In this embodiment, the rotor 200 can rotate relative to the stator 100 around the axis of the rotor disk 210. When the rotor 200 rotates, since the surface of the rolling element 230 is covered with a triboelectric material layer, the rolling element 230 can contact and rub with the first friction electrode 120 and the second friction electrode 130 respectively as the rotor 200 rotates. A potential difference is generated between the first friction electrode 120 and the second friction electrode 130, thereby generating an electrical signal between the rolling element 230 and the friction electrode pair during the friction process.

[0038] When the triboelectric sensing device of this embodiment is applied to a rotary-wing UAV, a triboelectric sensing device can be installed on each rotor of the UAV, and the rotor 200 is connected to the motor on the rotor, so that the motor can drive the rotor 200 to rotate relative to the stator 100 while driving the propeller to rotate. When the UAV is flying normally, the rolling element 230 in the rotor 200 generates a waveform signal every time it rotates by a preset angle. The spectrum of the signal can be obtained by analyzing the waveform signal, and then multiplied by a factor to obtain the rotor speed distribution. When the UAV is in different flight states, the speed of the motor on each rotor is also different. At this time, the speed of the motor and propeller can be monitored in real time by the triboelectric sensing device to deduce the flight state of the UAV, thereby ensuring the flight safety of the UAV.

[0039] It is worth mentioning that, in this embodiment, the surface of the rolling element 230 is coated with a triboelectric dielectric material layer, so that the rolling element 230 can act as a friction material in triboelectric nanogeneration. Simultaneously, the rolling element 230 can rotate relative to the rotor disk 210. When the rotor disk 210 rotates relative to the stator 100, the rolling element 230 can convert the friction between the rotor disk 210 and the stator 100 into rolling friction, making it easier for the rotor 200 to rotate relative to the stator 100, thereby ensuring the accuracy of signal measurement.

[0040] In some embodiments, reference Figure 3 and Figure 4 The stator disk 110 may be provided with at least two pairs of friction electrode pairs, which are evenly distributed along the circumference of the stator disk 110. Correspondingly, the rotor 200 may include at least two sets of rolling elements 230, which are arranged at intervals along the circumference of the rotor disk 210, corresponding to the aforementioned at least two pairs of friction electrode pairs. That is, the number of friction electrode pairs is the same as the number of sets of rolling elements 230.

[0041] Furthermore, the rotor disk 210 is also provided with two sets of mounting holes 220 corresponding to at least two sets of rolling elements 230, and each rolling element 230 is respectively installed in the mounting hole 220. The rolling element 230 and the mounting hole 220 can be clearance-fitted so that the rolling element 230 can rotate relative to the mounting hole 220, thereby realizing point contact between the rolling element 230 and the friction electrode pair.

[0042] In this embodiment, each set of rolling elements 230 may include at least one rolling element 230. Multiple sets of rolling elements 230 are arranged circumferentially along the rotor disk 210, which can keep the stator disk 110 and the rotor disk 210 balanced. The axis of the stator disk 110 coincides with the axis of the rotor disk 210, thereby ensuring that the rolling elements 230 can make contact when rubbing against the friction electrode pair.

[0043] In one optional implementation, when each group of rolling elements 230 includes multiple rolling elements, the preset projection plane is a plane perpendicular to the axis of the rotor disk 210. Therefore, the orthographic projection of each group of rolling elements 230 onto the projection plane can be fan-shaped. That is, the overall shape of each group of multiple rolling elements 230 can be the same as the shape of the first friction electrode 120 or the second friction electrode 130. In this way, when the rotor disk 210 rotates relative to the stator disk 110, each group of rolling elements 230 can have sufficient contact area with the first friction electrode 120 or the second friction electrode 130, thereby ensuring that the triboelectric sensing unit can generate a significant electrical signal, thus improving the accuracy of the detection.

[0044] For example, the orthographic projection of the plurality of rolling elements 230 in each group onto the projection plane may lie within the orthographic projection of the first friction electrode 120 onto the projection plane, or the orthographic projection of the plurality of rolling elements 230 in each group onto the projection plane may lie within the orthographic projection of the second friction electrode 130 onto the projection plane. In this case, the overall outline of the orthographic projection of the plurality of rolling elements 230 in each group onto the projection plane can be the same as the outline of the orthographic projection of the first friction electrode 120 or the second friction electrode 130 onto the projection plane, so as to arrange more rolling elements 230 in a limited space. In this way, when each group of rolling elements 230 contacts the first friction electrode 120 or the second friction electrode 130, the contact area between the rolling elements 230 and the first friction electrode 120 or the second friction electrode 130 increases, thereby generating a significant electrical signal.

[0045] In some embodiments, continue to refer to Figure 2 and Figure 3The stator 100 may include two stator disks 110, which are respectively disposed on both sides of the rotor disk 210 along the axial direction. Each stator disk 110 has a pair of friction electrodes on its side facing the rotor disk 210, and the pairs of friction electrodes on the two stator disks 110 are symmetrically distributed about the rotor 200 as an axis of symmetry. That is, a first friction electrode 120 disposed on one stator disk 110 is directly opposite a first friction electrode 120 disposed on the other stator disk 110, and a second friction electrode 130 disposed on one stator disk 110 is directly opposite a second friction electrode 130 disposed on the other stator disk 110.

[0046] In this embodiment, reference Figure 2 and Figure 5 The rolling element 230 protrudes from both sides of the rotor disk 210 along the axial direction, so that when both stator disks 110 and the rotor disk 210 are mounted on the annular bracket 300, the rolling element 230 can contact the friction electrode pairs on the stator disks 110 on both sides respectively. Thus, by setting two stator disks 110, the contact area between the rolling element 230 and the friction electrode pairs can be increased, thereby increasing the detected signal value and ensuring the accuracy of the rotational speed. In addition, the two stator disks 110 can also limit the rolling element 230 on the rotor disk 210. The mounting hole 220 of the rotor disk 210 can limit the rolling element 230 circumferentially, and the two stator disks 110 can limit the rolling element 230 axially, preventing the rolling element 230 from moving along the axial direction of the rotor disk 210 during rotation, which would prevent the rolling element 230 from contacting the friction electrode pairs.

[0047] As mentioned above, the two stator disks 110 are symmetrically arranged. When the two stator disks 110 are fixed to the annular bracket 300, the annular bracket 300 may be provided with a positioning structure so that the two stator disks 110 can be connected to the annular bracket 300 through the positioning structure to ensure that the two stator disks 110 can be aligned.

[0048] In specific implementation, such as Figure 3 and Figure 4 As shown, the annular support 300 is provided with a positioning groove 310, and the stator disk 110 is provided with a positioning part 140 protruding radially from the stator disk 110. The positioning part 140 can be embedded in the positioning groove 310 so that the stator disk 110 and the annular support 300 can be positioned. The annular support 300 is provided with at least two positioning grooves 310 on each side along the axial direction. The number of positioning parts 140 on the stator disk 110 is the same as the number of positioning grooves 310. Each positioning part 140 is engaged with the corresponding positioning groove 310 so that the stator disk 110 and the annular support 300 are initially positioned.

[0049] The positioning part 140 may also be provided with a connecting hole 141. When the positioning part 140 is engaged in the positioning groove 310, the connecting holes 141 of the two positioning parts 140 in the axial direction can be aligned. At this time, for example, the two stator discs 110 can be locked by passing a bolt through the connecting holes 141 of the two positioning parts 140, thereby improving the fixing effect between the two stator discs 110.

[0050] Furthermore, to ensure the fixation effect between the stator disk 110 and the annular bracket 300, such as Figure 3 As shown, the inner wall of the annular bracket 300 is also provided with a boss 330, which is arranged around the circumference of the annular bracket 300. The end face of the boss 330 along the axial direction is lower than the end face of the annular bracket 300 along the axial direction. When the stator disk 110 is assembled with the annular bracket 300, the stator disk 110 can be overlapped with the end face of the boss 300, so that the boss 330 can not only support the stator disk 110, but also limit the position of the stator disk 110.

[0051] The annular bracket 300 is also provided with a fixing groove 320, which can penetrate through the annular bracket 300 along its axial direction. Correspondingly, the stator disk 110 can also be provided with a fixing part 150 that protrudes radially from the stator disk 110. When the stator disk 110 is installed with the annular bracket 300, the stator disk 110 can overlap the end face of the boss 330, the fixing part 150 is engaged with the fixing groove 320, and at the same time, the positioning part 140 abuts against the bottom of the positioning groove 310, thereby completing the positioning and fixing of the stator disk 110 and the annular bracket 300, thus ensuring the alignment between the two stator disks 110.

[0052] A connecting shaft 240 can also be fixedly connected to the middle of the rotor disk 210. This connecting shaft 240 can be used to connect with the output shaft of the motor, so that the motor can drive the rotor disk 210 to rotate through the connecting shaft 240. Since the rotor disk 210 is located between the two stator disks 110, the stator disks 110 can also be provided with clearance holes to allow the connecting shaft 240 to pass through the clearance holes and protrude from the stator disks 110, thereby enabling it to connect with the motor.

[0053] like Figure 3 and Figure 5As shown, the connecting shaft 240 has a hollow internal structure. When the connecting shaft 240 is connected to the output shaft of the motor, the output shaft of the motor can pass through the connecting shaft 240 to ensure coaxiality between the output shaft of the motor and the connecting shaft 240. The connecting shaft 240 can also be provided with a fixing hole 241. When the output shaft of the motor passes through the connecting shaft 240, a steel shaft passing through the fixing hole 241 can be used to fix the connecting shaft 240 and the output shaft of the motor, thereby ensuring that the connecting shaft 240 and the output shaft of the motor can be relatively fixed.

[0054] In specific implementations, the materials of the first friction electrode 120 and the second friction electrode 130 can be metallic materials, conductive polymer materials, etc. For example, the materials of the first friction electrode 120 and the second friction electrode 130 can be copper foil, with a thickness of 0.03 mm to 0.5 mm. In some embodiments, the surfaces of the first friction electrode 120 and the second friction electrode 130 may also be covered with a dielectric material as a friction layer.

[0055] The material of the triboelectric material layer covering the surface of the rolling element 230 can be, for example, polytetrafluoroethylene, polydimethylsiloxane, polyamide, cellulose, silk fibroin, etc. Furthermore, in practical applications, the rolling element 230 can be coated only with a triboelectric material layer on its surface, or the entire rolling element 230 can be made of a triboelectric material layer.

[0056] Based on the same inventive concept, combined with Figures 1 to 5 This application embodiment may also provide a power device, which may include a body, a power module, and a triboelectric sensing device as described in the foregoing embodiments. Both the power module and the triboelectric sensing device are disposed within the body. The power module can be used to drive the body to move, and it can also be connected to the rotor 200 of the triboelectric sensing device to drive the rotor 200 to rotate relative to the stator 100.

[0057] In some embodiments, the power unit may be a rotary-wing unmanned aerial vehicle (UAV). The airframe of the rotary-wing UAV may include multiple arms, each arm being equipped with a power module and a propeller. The power module may be, for example, an electric motor, which drives the propeller to rotate relative to the arm, thereby enabling the airframe to fly due to the rotation of the propellers.

[0058] In this embodiment, the stator disk 110 of the triboelectric sensing device can be fixedly connected to the machine arm to ensure that the triboelectric sensing device can be stably connected to the machine arm. When the motor drives the propeller to rotate, it can also simultaneously drive the rotor disk 210 to rotate relative to the stator disk 110. During this process, an electrical signal is generated between the rolling element 230 and the friction electrode pair. When the speed of the motor changes, the magnitude or frequency of the electrical signal will also change accordingly.

[0059] In addition, a transmitter can be integrated into the fuselage, and a receiver can be set up on the transmitter matched with the rotary-wing UAV. The signals generated by each triboelectric sensing device can be output to the receiver through the transmitter. The receiver analyzes the signals through a preset program and displays the corresponding data analysis on the transmitter, thereby constructing a complete rotary-wing UAV rotation speed sensing system.

[0060] When applying the triboelectric sensing device to a rotary-wing unmanned aerial vehicle (UAV), experiments were conducted based on the triboelectric sensing device structure shown in the figure. In this experiment, both the first friction electrode 120 and the second friction electrode 130 were made of copper foil, and the thickness of both the first friction electrode 120 and the second friction electrode 130 was 35 μm. There were two of each of the first friction electrodes 120 and the second friction electrode 130, and each friction electrode occupied a width of 80° and a radius of 8.1 mm on the stator disk 110.

[0061] Furthermore, the rotor disk 210 has a thickness of 0.7 mm, the mounting hole 220 has a diameter of 2.1 mm, and the rolling element 230 has a diameter of 2 mm. Two sets of rolling elements 230 are provided corresponding to the first friction electrode 120 and the second friction electrode 130, each set including 13 rolling elements 230, and the two sets of rolling elements 230 are symmetrically distributed about the axis of symmetry of the rotor disk 210.

[0062] The rotary-wing UAV has four arms. When a triboelectric sensor is installed on one of the arms, it is connected between the motor and the propeller. The stator 100 of the triboelectric sensor is fixed relative to the arm, and the rotor 200 is connected to the output shaft of the motor. The rotor 200 rotates synchronously with the motor and the propeller.

[0063] In this experiment, a waveform signal is generated when the rotor disk 210 rotates 180°. Analysis of the waveform signal reveals its spectrum, which is then multiplied by a factor to obtain the rotational speed distribution. As the motor speed increases, the frequency of the signal generated by the triboelectric sensing device increases, and the number of wavenumbers per unit time increases. Conversely, as the motor speed decreases, the frequency of the signal generated by the triboelectric sensing device decreases, and the number of wavenumbers per unit time decreases.

[0064] like Figure 6 As shown, by constructing a rotorcraft drone speed sensing system, triboelectric sensing signals can be obtained. Processing these signals yields the real-time rotational speeds of the four propellers. The current flight status of the drone can be determined based on the propeller speeds, enabling the monitoring of improper drone operation. When operator error occurs, appropriate warnings can be issued. For example, if the drone's flight status changes too rapidly, the motor speed may fluctuate drastically, potentially causing the drone to enter an unstable state; in such cases, the warning system will issue a notification.

[0065] It should be noted that the triboelectric sensing device in this embodiment can be applied not only to the rotational speed monitoring of rotary-wing UAVs, but also to the rotational speed monitoring of submarine propellers, the rotational speed monitoring of wind turbines, and intelligent motors with built-in rotational speed monitoring functions, etc.

[0066] It is worth mentioning that the triboelectric sensing device in this embodiment is composed of a triboelectric electrode and a rolling element. It is not only simple in structure and low in cost, but also applicable to the speed monitoring of any rotating component.

[0067] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of this utility model. Therefore, if these modifications and variations of this utility model fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A triboelectric sensing device, comprising: The system includes a triboelectric sensing unit, which comprises a stator and a rotor arranged coaxially, the rotor being rotatable relative to the stator. The stator includes a stator disk and a pair of friction electrodes disposed on the side of the stator disk facing the rotor. The pair of friction electrodes includes a first friction electrode and a second friction electrode arranged circumferentially along the stator disk. The rotor includes a rotor disk and rolling elements disposed on the rotor disk. The rotor disk has a mounting hole, and the rolling elements are rotatably disposed in the mounting hole relative to the mounting hole. The surface of the rolling elements is covered with a triboelectric material layer, and a portion of the rolling elements protrudes from the side of the rotor disk facing the stator disk, so that when the rotor rotates relative to the stator, the rolling elements and the triboelectric electrode pair generate triboelectric signals through triboelectric contact.

2. The triboelectric sensing device of claim 1, wherein, The stator disk is provided with at least two pairs of friction electrodes, which are evenly distributed along the circumference of the stator disk. The rotor includes at least two sets of rolling elements corresponding to the at least two pairs of friction electrodes, and the at least two sets of rolling elements are spaced apart along the circumference of the rotor disk. The rotor disk is provided with at least two sets of mounting holes corresponding to the at least two sets of rolling elements, and each rolling element is installed in the respective mounting hole.

3. The triboelectric sensing device according to claim 2, characterized in that, Each set of rolling elements includes at least one of the rolling elements, and the rolling element has a clearance fit with the mounting hole.

4. The triboelectric sensing device according to claim 3, characterized in that, When each group of rolling elements includes multiple rolling elements, the orthographic projection of the multiple rolling elements on the projection plane is fan-shaped; The orthographic projections of the plurality of rolling elements on the projection plane are located within the orthographic projection of the first friction electrode on the projection plane, or the orthographic projections of the plurality of rolling elements on the projection plane are located within the orthographic projection of the second friction electrode on the projection plane; The projection plane is a plane perpendicular to the axis of the rotor disk.

5. The triboelectric sensing device according to claim 1, characterized in that, The stator includes two stator disks, which are respectively disposed on both sides of the rotor; Each of the stator disks is provided with a pair of friction electrodes on the side facing the rotor, and the pairs of friction electrodes provided on the two stator disks are symmetrically distributed with the rotor as the axis of symmetry. The rolling element protrudes from both sides of the rotor disk, so that the rolling element generates a triboelectric signal with the friction electrode pairs on both sides respectively.

6. The triboelectric sensing device according to claim 1, characterized in that, The triboelectric sensing unit also includes an annular bracket, the stator disk is fixedly connected to the annular bracket, and the rotor disk is disposed inside the annular bracket.

7. The triboelectric sensing device according to claim 6, characterized in that, The inner wall of the annular support is provided with a boss, which is arranged along the circumference of the annular support, and the stator disk overlaps the boss.

8. The triboelectric sensing device according to claim 6, characterized in that, The annular support is provided with a positioning groove, and the stator disk is provided with a positioning part, which is embedded in the positioning groove.

9. A power unit, characterized in that, The device includes a body, a power module, and a triboelectric sensing device as described in any one of claims 1 to 8. The power module and the triboelectric sensing device are disposed in the body. The power module is connected to the rotor of the triboelectric sensing device to drive the rotor to rotate relative to the stator.

10. The power unit according to claim 9, characterized in that, The power unit is a rotary-wing unmanned aerial vehicle; The machine body includes multiple arms, each arm is equipped with a propeller, and each arm is equipped with a power module and a triboelectric sensing device. The power module is used to drive the propeller to rotate relative to the arm, and the stator of the triboelectric sensing device is fixedly connected to the arm.

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