CN-121973966-A - Spherical tethered unmanned aerial vehicle and control method

CN121973966ACN 121973966 ACN121973966 ACN 121973966ACN-121973966-A

Abstract

The invention discloses a spherical tethered unmanned aerial vehicle and a control method, wherein the spherical tethered unmanned aerial vehicle comprises a spherical shell, a self-stabilizing rotating ring, a self-stabilizing rotating shaft and a multi-rotor unmanned aerial vehicle, the self-stabilizing rotating ring is positioned on the inner side of the spherical shell, the upper end of the self-stabilizing rotating ring is rotationally connected with the upper pole of the spherical shell through a first encoder, the lower end of the self-stabilizing rotating ring is rotationally connected with the lower pole of the spherical shell through a first electric slip ring, the self-stabilizing rotating shaft is transversely arranged on the inner side of the self-stabilizing rotating ring, one end of the self-stabilizing rotating shaft is rotationally connected with one side of the self-stabilizing rotating ring through a second encoder, the other end of the self-stabilizing rotating shaft is rotationally connected with the other side of the self-stabilizing rotating ring through a second electric slip ring, the multi-rotor unmanned aerial vehicle is arranged on the self-stabilizing rotating shaft, a laser radar and a camera are further arranged on the self-stabilizing rotating shaft, and a tension sensor is further arranged on the lower end of the spherical shell.

Inventors

HU JUN
YAO YONGHUAN
XIONG JIAN
WANG CHENJIE
XIAO PENG
WU LIGUI
LIU LIANWEI
GAN HUIMIN
QIU TAO
LI YAJUN
LI WEIXIAN
TONG YING

Assignees

中国长江电力股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260119

Claims (10)

1. A spherical tethered unmanned aerial vehicle is characterized by comprising a spherical shell (10), a self-stabilizing rotating ring (20), a self-stabilizing rotating shaft (30) and a multi-rotor unmanned aerial vehicle (40), wherein the self-stabilizing rotating ring (20) is positioned on the inner side of the spherical shell (10), the upper end of the self-stabilizing rotating ring (20) is rotatably connected with the upper pole of the spherical shell (10) through a first encoder (11), the lower end of the self-stabilizing rotating ring (20) is rotatably connected with the lower pole of the spherical shell (10) through a first electric slip ring (12), the self-stabilizing rotating shaft (30) is transversely arranged on the inner side of the self-stabilizing rotating ring (20), one end of the self-stabilizing rotating shaft (30) is rotatably connected with one side of the self-stabilizing rotating ring (20) through a second encoder (21), the other end of the self-stabilizing rotating shaft (30) is rotatably connected with the other side of the self-stabilizing ring (20) through a second electric slip ring (22), the multi-rotor unmanned aerial vehicle (40) is mounted on the self-stabilizing rotating shaft (30), a laser radar (50) and a camera head (60) are further mounted on the self-stabilizing rotating shaft (30), the lower end of the self-stabilizing rotating ring (20) is transversely arranged on the inner side of the self-stabilizing rotating ring (20) through a first encoder (12), and the first encoder (70) is fixedly connected with the first encoder (70), and the first electric sensor (70) is fixedly connected with the first electric sensor (70), and the first electric sensor (70) through the first encoder (70) The second encoder (21) and the second electric slip ring (22) are electrically connected, and the second electric slip ring (22) is electrically connected with the multi-rotor unmanned aerial vehicle (40), the laser radar (50) and the camera (60).
2. A tethered spherical unmanned aerial vehicle according to claim 1, wherein the rotation axes of the self-stabilizing rotation ring (20) and the self-stabilizing rotation shaft (30) are mutually orthogonal, and the rotation centers of the two are coincident with the geometric center of the spherical shell (10).
3. The spherical tethered unmanned aerial vehicle according to claim 1, wherein the spherical shell (10) is composed of a plurality of non-coplanar rigid rings (101), fixing points among the rigid rings (101) are an upper pole and a lower pole of the spherical shell (10), and the middle part of each rigid ring (101) is fixed with an equatorial ring (102).
4. The control method for the spherical tethered unmanned aerial vehicle according to claim 1 is characterized by comprising the following steps: S1, acquiring an environmental point cloud acquired by a laser radar (50), angular speed and acceleration of a multi-rotor unmanned aerial vehicle (40) output by an IMU, an absolute angle between a self-stabilizing rotating ring (20) and a self-stabilizing rotating shaft (30) fed back by an encoder, and a mooring line tension value output by a tension sensor (70) in real time; S2, constructing a state observation model containing tethered line tension disturbance items based on an extended Kalman filter, performing tight coupling fusion on multi-source data, and outputting disturbance-compensated pose estimation; S3, taking the output pose estimation as input, and dynamically generating a flight track meeting constraint in a local map by combining a preset target observation area direction: And S4, constructing a unified dynamics model comprising aerodynamic drag of the spherical shell (10), elastic tension of the mooring line (1), inertia coupling of the self-stabilizing rotating ring (20) and the self-stabilizing rotating shaft (30), and adopting model prediction control to solve a thrust distribution instruction of a propeller of the multi-rotor unmanned aerial vehicle (40) by rolling optimization with the generated flight track as a reference, so that the multi-rotor unmanned aerial vehicle (40) acts cooperatively with the self-stabilizing rotating ring (20) and the self-stabilizing rotating shaft (30).
5. The control method according to claim 4, wherein in S3, the EGO-Planner algorithm is used to dynamically generate a flight trajectory in the local map satisfying the following constraints: Obstacle avoidance safety; the tethered line length rate of change and tension gradient do not exceed a safety threshold to prevent entanglement or breakage; the visual axis of the camera (60) is continuously aligned with the target area.
6. A control method according to claim 5, characterized in that the EGO-Planner algorithm models the current winding state of the tethered line (1) as a virtual obstacle when generating the trajectory and dynamically excludes paths leading to further winding in the planning space.
7. A control method according to claim 6, wherein the total length of the current mooring line is defined as A winding sensitivity function is introduced: ; wherein: Is the included angle between the mooring line and the vertical direction; is a speed vector of the unmanned aerial vehicle; Defining an anti-wind security constraint as: ; wherein: Is a weight coefficient; A preset threshold value for winding; in the local trajectory optimization of EGO-Planner, the above formula is added to the quadratic programming as a hard constraint: ; ; wherein: The three-dimensional position coordinate track of the multi-rotor unmanned aerial vehicle in the ground inertial coordinate system is provided; Is a reference track; For a constraint, the planned trajectory is required No collision with static or dynamic obstacles known in the environment occurs in the whole flying process; Is a winding risk index; A preset threshold value for winding; representing the direction of the visual axis of the camera Vector with target area direction Cosine value of included angle; Is the maximum allowable deviation angle.
8. A control method according to claim 5, characterized in that if it is detected that the mooring line (1) tension exceeds a preset upper threshold, an emergency retraction strategy is triggered, a retraction trajectory is generated towards the mooring base, and the flying height is lowered to release the tension.
9. A control method according to claim 4, wherein in S4, the optimization objective function of the model predictive control minimizes the following three simultaneously: the position and posture of the actual track and the reference track deviate; An L2 norm of the tethered line tension rate of change; an angular error of the camera (60) viewing axis from the target area.
10. A control method according to claim 9, wherein in S4, The overall translation equation is: ; wherein: representing the overall mass of the unmanned aerial vehicle; representing an acceleration vector of the mass center of the unmanned aerial vehicle in an inertial coordinate system; Representing a rotation matrix; representing the total thrust vector produced by the rotor; representing gravitational acceleration; expressed as a vertical unit vector in an inertial coordinate system, directed downward for expressing the direction of gravity; The aerodynamic resistance of the spherical shell structure is represented; A unit direction vector for the mooring line; The inertia coupling rotation equation of the self-stabilizing rotation ring (20) and the self-stabilizing rotation shaft (30) is as follows: ; wherein: representing the moment of inertia of the self-stabilizing rotating ring; Representing the moment of inertia of the self-stabilizing rotating shaft; Representing self-stabilizing rotary ring drive torque; Representing self-stabilizing rotational shaft drive torque; Representing a tension-self-stabilizing rotation coefficient function; Representing yaw angle, i.e. the rotation angle of the self-stabilizing rotation ring relative to the spherical shell; Representing pitch angle, i.e. the pitch angle of the self-stabilizing rotation axis relative to the self-stabilizing rotation ring; And The geometrical factor is derived from the arm projection relation of the tension on two-stage rotation, so that the nonlinear coupling characteristic between the tension and rotation of the mooring line is reflected; On the basis, multi-objective MPC optimization is designed: wherein N represents the predicted time domain length, k represents the discrete time index; representing the three-dimensional position state of the unmanned aerial vehicle predicted in the kth step; representing the expected position value of the reference track at the kth step; representing the predicted attitude angle of the kth step; Representing a reference pose; A mooring line tension value predicted for the kth step; the tension change rate is represented, and the change amplitude of the tension in unit time is represented; A weight coefficient representing a tension smoothing term for adjusting the importance of tension variation suppression; the weight coefficient representing the visual axis precision item is used for adjusting the importance of the pointing precision of the camera; camera visual axis direction representing kth prediction Direction to the target area The angle between them indicates the pointing deviation.

Description

Spherical tethered unmanned aerial vehicle and control method Technical Field The invention relates to the technical field of spherical unmanned aerial vehicles, in particular to a spherical tethered unmanned aerial vehicle and a control method. Background Along with the increase of application demands of fields such as industrial monitoring, emergency rescue and the like to unmanned aerial vehicles, the tethered unmanned aerial vehicle gradually becomes a popular choice by virtue of the advantage of long-time endurance and the advantage of collision resistance of the spherical unmanned aerial vehicle. However, the tethered unmanned aerial vehicle and the spherical unmanned aerial vehicle on the market at present do not combine each other, and the technical difficulties are combined in aspects of power supply, signal transmission, spherical shell and tethered line anti-winding, and structural design defects generally exist. In a complex narrow space or a regional operation scene with more obstacles, the collision risk of the unmanned aerial vehicle is extremely high, and once the unmanned aerial vehicle collides, the unmanned aerial vehicle not only interrupts tasks, but also can cause equipment damage and data loss. The mooring lines are very easy to intertwine in the flight process, and especially when the attitude of the unmanned aerial vehicle changes, the winding problem is more serious, and the reliability and the safety of equipment are seriously affected. In order to improve the adaptability and stability of the tethered unmanned aerial vehicle in a complex environment, no novel spherical tethered unmanned aerial vehicle which has an anti-collision and anti-winding function and can maintain a stable flight state exists in the prior art at present. For example, chinese patent document CN116780297a, publication (bulletin) day 2023.09.19, discloses a tethered unmanned aerial vehicle cable anti-wind connection device, which however cannot protect the unmanned aerial vehicle from collision. In addition, when unmanned aerial vehicle carries out driftage or every single move action, the mooring cable easily takes place to twist reverse, in order to avoid the winding, needs restriction unmanned aerial vehicle rotational freedom degree, has sacrificed unmanned aerial vehicle's directional flexibility. Disclosure of Invention The invention aims to provide a spherical tethered unmanned aerial vehicle and a control method, which solve the problems of cable winding, limited gesture and uncooperation control of the existing tethered unmanned aerial vehicle and realize integrated operation capability of no winding, omni-directional gesture adjustment and high-precision pointing. In order to achieve the above object, in a first aspect, the application provides a spherical tethered unmanned aerial vehicle, which comprises a spherical shell, a self-stabilizing rotating ring, a self-stabilizing rotating shaft and a multi-rotor unmanned aerial vehicle, wherein the self-stabilizing rotating ring is positioned on the inner side of the spherical shell, the upper end of the self-stabilizing rotating ring is rotationally connected with the upper pole of the spherical shell through a first encoder, the lower end of the self-stabilizing rotating ring is rotationally connected with the lower pole of the spherical shell through a first electric slip ring, the self-stabilizing rotating shaft is transversely arranged on the inner side of the self-stabilizing rotating ring, one end of the self-stabilizing rotating shaft is rotationally connected with one side of the self-stabilizing rotating ring through a second encoder, the other end of the self-stabilizing rotating shaft is rotationally connected with the other side of the self-stabilizing rotating ring through a second electric slip ring, the multi-rotor unmanned aerial vehicle is mounted on the self-stabilizing rotating shaft, a laser radar and a camera are further mounted on the self-stabilizing rotating shaft, the lower end of the spherical shell is fixedly connected with a tension sensor, the mooring line is fixedly connected with the detection end of the tension sensor, and the mooring line is electrically connected with the tension sensor and the first electric slip ring, the first electric slip ring is electrically connected with the first encoder and the second electric slip ring and the multi-rotor unmanned aerial vehicle. The rotation axes of the self-stabilizing rotation ring and the self-stabilizing rotation shaft are mutually orthogonal, and the rotation centers of the self-stabilizing rotation ring and the self-stabilizing rotation shaft are coincident with the geometric center of the spherical shell. The spherical shell consists of a plurality of non-coplanar rigid circular rings, the fixed points among the rigid circular rings are the upper pole and the lower pole of the spherical shell, and the middle part of each rigid circular ring is fixed with the equatori