Two-degree-of-freedom holder of unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicles, in particular to an unmanned aerial vehicle two-degree-of-freedom holder which comprises a platform, a rotating mechanism, a pitching mechanism and a camera, the rotating mechanism is connected with the platform, the pitching mechanism comprises a connecting frame body, a pitching frame body and a pitching motor, and the connecting frame body is connected with the output end of the rotating mechanism; the pitching frame body is rotatably connected with the connecting frame body, the outer side of the connecting frame body is provided with a meshing piece, the output end of the pitching motor is provided with a first driving gear, the first driving gear is meshed with the meshing piece, and the camera is arranged at the front end of the pitching frame body. According to the invention, 360-degree dead-angle-free rotation of the yaw angle of the holder is realized, a fire source, trapped persons or key facilities can be quickly positioned in scenes such as fire reconnaissance and the like, the emergency response efficiency and the search coverage range are remarkably improved, pitching motion up to 90 degrees or even a larger range can be realized, and the system is suitable for large-scale popularization and application. The requirement for clear observation of vertical spaces such as windows, roofs and ground pits of high-rise buildings is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicles, and particularly relates to a two-degree-of-freedom gimbal for unmanned aerial vehicles. BACKGROUND

[0002] With the wide application of unmanned aerial vehicles in fire rescue, power inspection, security monitoring and other fields, the gimbal system carried by the unmanned aerial vehicles as a stable and adjustable platform for core sensing loads plays a decisive role in the efficiency and safety of task execution. In particular, in complex and high-risk operating environments such as high-rise building fires, forest fire reconnaissance and other scenes, the gimbal of the unmanned aerial vehicle needs to have the ability of fast, accurate and wide-range adjustment of the viewing angle to achieve efficient scanning and continuous tracking of the target area.

[0003] At present, the common two-degree-of-freedom gimbal for unmanned aerial vehicles is usually composed of a yaw rotation mechanism and a pitch adjustment mechanism, which adjusts the pointing direction of the camera and other sensors by controlling the movement of the gimbal itself, thereby reducing the frequent maneuvering of the unmanned aerial vehicle body. However, the gimbal system in the prior art still has many shortcomings: in terms of yaw control, some gimbals rely on the overall turning of the unmanned aerial vehicle to realize the switching of the horizontal viewing angle, which not only responds slowly, but also has poor stability in complex airflow environment, making it difficult to achieve 360° continuous and smooth omnidirectional scanning; in terms of pitch control, the traditional design mostly uses motor direct drive or simple linkage mechanism, and the pitch angle is limited, usually less than 60°, which is difficult to meet the observation demand of vertical space such as high-rise building windows and roofs. In order to adjust the viewing angle, the operator often needs to control the unmanned aerial vehicle to ascend, descend or fly forward, which not only increases the flight risk and prolongs the response time, but also exposes the unmanned aerial vehicle to dangerous areas such as high temperature, smoke or structure collapse for a long time, significantly increasing the task risk and energy consumption. SUMMARY

[0004] The present application aims to at least solve the technical problems existing in the prior art. To this end, the present application provides a two-degree-of-freedom gimbal for unmanned aerial vehicles, which ensures that the visual camera can quickly and smoothly complete omnidirectional scanning and focus on key areas, thereby improving rescue efficiency and ensuring operating safety.

[0005] The unmanned aerial vehicle two-degree-of-freedom holder according to some embodiments of the present application comprises a platform, a rotating mechanism, a pitching mechanism and a camera, the rotating mechanism is connected with the platform, the pitching mechanism comprises a connecting frame body, a pitching frame body and a pitching motor, the connecting frame body is connected with the output end of the rotating mechanism, the pitching motor is arranged on the pitching frame body, the middle part of the connecting frame body is provided with an avoiding slot, the two sides of the pitching frame body are rotatably connected with the two sides of the bottom of the avoiding slot respectively, the outer side of the connecting frame body is provided with an engaging piece, the output end of the pitching motor is provided with a first driving gear, the first driving gear is engaged with the engaging piece, the camera is arranged at the front end of the pitching frame body, the engaging piece is provided with an arc-shaped engaging part, and the first driving gear is engaged with the engaging part.

[0006] The unmanned aerial vehicle two-degree-of-freedom holder according to some embodiments of the present application has at least the following beneficial effects:

[0007] The present application drives the connecting frame body and the whole pitching mechanism to continuously rotate in the horizontal direction through the rotating mechanism, and realizes 360° omnidirectional and dead-angle-free rotation of the holder yaw angle through the transmission of the engaging piece on the outer side of the connecting frame body and the first driving gear at the output end of the pitching motor, so that the visual camera carried can independently complete rapid scanning of the surrounding environment without relying on the turning of the unmanned aerial vehicle body, can quickly locate the fire source, trapped personnel or key facilities in fire fighting reconnaissance and other scenes, significantly improves the emergency response efficiency and search coverage, and the pitching mechanism adopts the avoiding slot structure on the connecting frame body, so that the pitching frame body can rotate by the two sides of the bottom, and the first driving gear driven by the pitching motor is engaged with the engaging piece on the outer side of the connecting frame body to drive and transmit, so that the pitching angle of the pitching frame body and the camera can be accurately controlled, the problem that the pitching angle of the traditional holder is limited is effectively overcome, the pitching motion of up to 90° or even a larger range can be realized, the clear observation demand for vertical space such as windows of high-rise buildings, roofs and ground pits is met, and the operator does not need to frequently control the unmanned aerial vehicle to ascend, descend, fly forward or turn when adjusting the observation angle, which not only reduces the exposure time and flight distance of the unmanned aerial vehicle in high temperature, thick smoke, strong airflow or unstable structure area, effectively reduces the flight safety risk, but also significantly reduces the flight energy consumption, prolongs the endurance time of a single task.

[0008] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the rotating mechanism comprises an end cover, a bearing, a rotating motor, a rotating disc gear and a connecting disc, a rotating groove is formed on the platform, the bearing is arranged on the inner wall of the rotating groove, the end cover is arranged on the inner side of the bearing, the bottom of the end cover is connected with the connecting disc, the bottom of the connecting disc is connected with the connecting frame body, the rotating disc gear is arranged on the outer side of the end cover, the rotating motor is connected with the bottom of the platform, the output end of the rotating motor is provided with a second driving gear, and the second driving gear is engaged with the rotating disc gear.

[0009] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the bottom of the platform is provided with a fixing disc, and the rotating motor is arranged on the fixing disc.

[0010] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the yaw axis of the end cover is set as a fixed axis rotation angle β, the pitch axis of the pitch frame body is set as a fixed axis rotation angle γ, and the following relationship is established:

[0011]

[0012]

[0013] wherein M1 is the fixed axis rotational inertia of the yaw axis, M2 is the fixed axis rotational inertia of the pitch axis, R Y2 is the radius of the rotating disc gear, R Z2 is the radius of the engaging part, and R Z3 is the radius of the first driving gear.

[0014] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the tooth number ratio of the first driving gear to the engaging part is 1:3, the torque ratio of the first driving gear to the engaging part is 1:3, the module of the first driving gear and the engaging part is 2.5, and the required torque of the pitch motor is

[0015] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the tooth number ratio of the second driving gear to the rotating disc gear is 1:2.5, the torque ratio of the second driving gear to the rotating disc gear is 1:2.5, the module of the second driving gear and the rotating disc gear is 2, and the required torque of the pitch motor is

[0016] A two-degree-of-freedom gimbal of a UAV according to some embodiments of the present application, the engaging part is a quarter gear.

[0017] The unmanned aerial vehicle two-degree-of-freedom holder according to some embodiments of the present application is provided with a speed regulator on the pitching frame body, the speed regulator is electrically connected with the pitching motor, the bottom of the pitching frame body is provided with a picture transmission mounting plate, the picture transmission mounting plate is provided with a picture transmission module, and the picture transmission module is electrically connected with the camera.

[0018] The unmanned aerial vehicle two-degree-of-freedom holder according to some embodiments of the present application is provided with a protruding plate at the front end of the pitching frame body, the camera is arranged on the protruding plate, and the bottom of the protruding plate is provided with an infrared thermal imaging module.

[0019] The unmanned aerial vehicle two-degree-of-freedom holder according to some embodiments of the present application is provided with a protruding plate at the front end of the pitching frame body, the camera is arranged on the protruding plate, and the bottom of the protruding plate is provided with an infrared thermal imaging module.

[0020] Additional aspects and advantages of the present application will be made apparent from the following description, which proceeds with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1 It is a structural schematic diagram of the embodiment of the present application.

[0023] Figure 2 It is a structural schematic diagram of the pitching mechanism of the embodiment of the present application.

[0024] Figure 3 It is a structural schematic diagram of the rotating mechanism of the embodiment of the present application.

[0025] Reference signs: 1, platform, 2, rotating mechanism, 3, pitching mechanism, 4, camera, 5, connecting frame body, 6, pitching frame body, 7, pitching motor, 8, position avoiding groove, 9, engaging part, 10, first driving gear, 11, end cover, 12, bearing, 13, rotating motor, 14, rotating disc gear, 15, connecting disc, 17, second driving gear, 18, fixed disc, 19, engaging part, 20, speed regulator, 21, picture transmission mounting plate, 22, picture transmission module, 23, protruding plate, 24, infrared thermal imaging module. DETAILED DESCRIPTION

[0026] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0027] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by the upper, lower, left, right, front, back and the like, is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the modules or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0028] In the description of the present application, if the first, second, etc. are described, they are only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of technical features indicated.

[0029] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0030] As shown in Figure 1-Figure 3 The embodiment of the present application provides a two-degree-of-freedom holder of unmanned aerial vehicle.

[0031] A two-degree-of-freedom holder of unmanned aerial vehicle, comprising a platform 1, a rotating mechanism 2, a pitching mechanism 3 and a camera 4, the rotating mechanism 2 is connected with the platform 1, the pitching mechanism 3 comprises a connecting frame body 5, a pitching frame body 6 and a pitching motor 7, the connecting frame body 5 is connected with the output end of the rotating mechanism 2, the pitching motor 7 is arranged on the pitching frame body 6, a position avoiding groove 8 is formed in the middle part of the connecting frame body 5, the two sides of the pitching frame body 6 are rotatably connected with the two sides of the bottom of the position avoiding groove 8 respectively, a meshing piece 9 is arranged on the outer side of the connecting frame body 5, a first driving gear 10 is arranged on the output end of the pitching motor 7, the first driving gear 10 is engaged with the meshing piece 9, and the camera 4 is arranged at the front end of the pitching frame body 6.

[0032] The present application drives the connecting frame body 5 and the whole tilt mechanism 3 to continuously rotate in the horizontal direction through the rotating mechanism 2, and realizes 360° full range and no dead angle rotation of the yaw angle of the holder by combining the meshing piece 9 outside the connecting frame body 5 with the first driving gear 10 at the output end of the tilt motor 7, so that the visual camera 4 carried can independently complete the rapid scanning of the surrounding environment without relying on the body turning of the unmanned aerial vehicle, and can quickly locate the fire source, trapped personnel or key facilities in the fire fighting reconnaissance scene, thereby significantly improving the emergency response efficiency and search coverage. Meanwhile, the tilt mechanism 3 adopts the avoidance groove 8 structure on the connecting frame body 5, so that the tilt frame body 6 can rotate by a large angle around the bottom of both sides, and the tilt motor 7 drives the first driving gear 10 to mesh with the meshing piece 9 outside the connecting frame body 5, so as to accurately control the tilt angle of the tilt frame body 6 and the camera 4, effectively overcome the problem of limited tilt angle of the traditional holder, and realize a tilt motion of up to 90° or even a larger range, thereby meeting the clear observation demand of high-rise building windows, roofs, ground pits and other vertical spaces. When the operator adjusts the observation angle, it is not necessary to frequently control the unmanned aerial vehicle to rise, descend, fly forward or turn, which not only reduces the exposure time and flight distance of the unmanned aerial vehicle in high temperature, thick smoke, strong airflow or unstable structure area, effectively reduces the flight safety risk, but also significantly reduces the flight energy consumption, prolongs the endurance time of single task.

[0033] The rotating mechanism 2 includes an end cover 11, a bearing 12, a rotating motor 13, a rotating disc gear 14 and a connecting disc 15. A rotating groove is formed in the platform 1. The bearing 12 is arranged on the inner wall of the rotating groove. The end cover 11 is arranged on the inner side of the bearing 12. The bottom of the end cover 11 is connected with the connecting disc 15. The bottom of the connecting disc 15 is connected with the connecting frame body 5. The rotating disc gear 14 is arranged on the outer side of the end cover 11. The rotating motor 13 is connected with the bottom of the platform 1. The output end of the rotating motor 13 is provided with a second driving gear 17. The second driving gear 17 is engaged with the rotating disc gear 14. Specifically, the rotating motor 13 works. The second driving gear 17 rotates to drive the rotating disc gear 14 to rotate, and then drives the end cover 11 to rotate as a whole. The transmission mode of the rotating disc gear 14 and the second driving gear 17 is adopted to realize large torque and stable transmission in the yaw direction. The bearing 12 support structure ensures that the rotating mechanism 2 runs stably, has low noise and high rotation accuracy, and improves image stability and shooting quality.

[0034] Specifically, the tilt motor 7 and the rotating motor 13 are brushless motors.

[0035] In some embodiments, the bearing 12 is a deep groove ball bearing.

[0036] The unmanned aerial vehicle two-degree-of-freedom holder provided in the embodiment is characterized in that a fixed disc 18 is arranged at the bottom of the platform 1, and the rotating motor 13 is arranged on the fixed disc 18.

[0037] The unmanned aerial vehicle two-degree-of-freedom holder provided in the embodiment is characterized in that an arc-shaped engaging part 19 is arranged on the engaging part 9, and the first driving gear 10 is engaged with the engaging part 19.

[0038] The unmanned aerial vehicle two-degree-of-freedom holder provided in the embodiment is characterized in that the yaw shaft fixed-axis rotation angle of the end cover 11 is β, and the pitch shaft fixed-axis rotation angle of the pitch frame body 6 is γ.

[0039]

[0040] Wherein, α is the rotation angle acceleration.

[0041] Kinetic energy theorem:

[0042] dT=dA (2);

[0043] Fixed-axis kinetic energy theorem:

[0044]

[0045] Wherein, J d is the motor rotation inertia; J L is the load rotation inertia.

[0046] The total kinetic energy T of the holder is obtained according to the formula (1)-(3):

[0047]

[0048] Wherein, J Z , J YJ Z3 J Y2 β, γ are respectively the yaw axis, pitch axis fixed axis rotation angle.

[0049] The two rotating shafts rotation torque can be obtained from the Lagrange equation:

[0050]

[0051] The gimbal stabilization equation is obtained by substituting formula (5), (6) into formula (4):

[0052] (J Y2 +J Z3 )β+(J Z2 +J Z3 )sin 2 β=M1

[0053] J Z3 (γ-sinβ-βcosβ)=M2

[0054] The rotation inertia formula is: After being brought in, it has:

[0055]

[0056] Wherein, M1 is the fixed axis rotation inertia of the yaw axis, M2 is the fixed axis rotation inertia of the pitch axis, R Y2 is the radius of the rotating disc gear, R Z2 is the radius of the meshing part, R Z3 is the radius of the first driving gear.

[0057] The first driving gear 10 and the meshing part 19 have a gear ratio of 1:3, the first driving gear 10 and the meshing part 19 have a torque ratio of 1:3, the first driving gear 10 and the meshing part 19 have a modulus of 2.5, and the required torque of the pitch motor 13 is Specifically, the gear ratio of 1:3 is used to realize speed reduction and torque increase, which significantly improves the output torque, so that a small power pitch motor can drive the camera to complete the stable pitch action, reduces the power consumption and the motor volume, the modulus 2.5 ensures sufficient tooth root strength, improves the transmission reliability, and prolongs the service life.

[0058] The second driving gear 17 and the rotating disc gear 14 have a gear ratio of 1:2.5, the second driving gear 17 and the rotating disc gear 14 have a torque ratio of 1:2.5, the second driving gear 17 and the rotating disc gear 14 have a modulus of 2, and the required torque of the pitch motor is Specifically, through the transmission ratio of 1:2.5, the yaw motion is efficiently transmitted while ensuring sufficient torque and response speed; the small modulus is suitable for light load and high speed scenes, reduces the weight of the gear, and meets the requirement of unmanned aerial vehicle for light weight, and the overall design balances the performance and weight.

[0059] The motor drive in the gimbal selects L6234 drive chip. L6234 is a drive chip composed of three half bridges, which can drive a brushless DC motor.

[0060] The current and torque calculation formula of the brushless motor at a certain speed is as follows:

[0061]

[0062] In the formula, I is the working current (A), M is the motor torque (Nm), Ud is the working voltage, D is the PWM duty cycle, △U is the on-voltage drop of L6234 (V), which can be ignored, n is the speed (rpm), kv is the motor inherent parameter (rpm / V), R is the motor internal resistance (W), and Io is the motor no-load current (A). The gimbal motor is mainly angle control, and the speed n and I o can be ignored. The formula can be simplified as follows:

[0063]

[0064] The appropriate working parameters and type of brushless motor under PWM control can be obtained, and the PWM duty cycle is adjusted to accurately control the motor to rotate to any angle.

[0065] The two-degree-of-freedom gimbal of the unmanned aerial vehicle described in the embodiment is provided with a quarter gear as the meshing part 19. Specifically, the quarter circular gear is used as the meshing part 19, and the tooth shape is arranged only in the required rotation range, thereby saving space and avoiding friction and interference caused by the invalid meshing area.

[0066] The two-degree-of-freedom gimbal of the unmanned aerial vehicle described in the embodiment is provided with a speed regulator 20 on the pitch frame body 6, the speed regulator 20 is electrically connected with the pitch motor 7, the bottom of the pitch frame body 20 is provided with a photo transmission mounting plate 21, the photo transmission mounting plate 21 is provided with a photo transmission module 22, and the photo transmission module 22 is electrically connected with the camera 4. Specifically, the integrated speed regulator 20 realizes accurate speed control of the pitch motor 7, improves the smoothness of the gimbal motion and the tracking accuracy; the photo transmission module 22 is arranged close to the camera 4, shortens the signal transmission path, reduces interference, improves the stability and real-time performance of video transmission, and enhances the aerial photography experience.

[0067] The unmanned aerial vehicle two-degree-of-freedom holder described in the embodiment is provided with a protruding plate 23 at the front end of the pitching frame body 6, the camera 4 is arranged on the protruding plate 23, and the bottom of the protruding plate 23 is provided with an infrared thermal imaging module 24. Specifically, the camera 4 is moved forward by the protruding plate 23, the field of view is expanded, and the fuselage is prevented from shielding the picture; the integrated infrared thermal imaging module 24 can detect fire sources and temperature abnormal points by using infrared thermal imaging.

[0068] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A two-degree-of-freedom gimbal for an unmanned aerial vehicle, characterized by: It includes a platform, a rotating mechanism, a pitch mechanism and a camera, the rotating mechanism is connected to the platform, the pitch mechanism includes a connecting frame, a pitch frame and a pitch motor, the connecting frame is connected to the output end of the rotating mechanism, the pitch motor is arranged on the pitch frame, a avoidance groove is provided in the middle of the connecting frame, the two sides of the pitch frame are rotatably connected to the two sides of the bottom of the avoidance groove, the outer side of the connecting frame is provided with a meshing piece, the output end of the pitch motor is provided with a first driving gear, the first driving gear is meshed with the meshing piece, the camera is arranged at the front end of the pitch frame, the meshing piece is provided with an arc-shaped meshing portion, and the first driving gear is meshed with the meshing portion.

2. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 1, characterized in that: The rotating mechanism includes an end cover, a bearing, a rotating motor, a turntable gear and a connecting plate. A rotating groove is opened on the platform. The bearing is arranged on the inner wall of the rotating groove. The end cover is arranged on the inner side of the bearing. The bottom of the end cover is connected to the connecting plate. The bottom of the connecting plate is connected to the connecting frame. The turntable gear is arranged on the outer side of the end cover. The rotating motor is connected to the bottom of the platform. The output end of the rotating motor is provided with a second driving gear, and the second driving gear is engaged with the turntable gear.

3. The two-degree-of-freedom gimbal of an unmanned aerial vehicle according to claim 2, characterized in that: A fixed disk is provided at the bottom of the platform, and the rotating motor is provided on the fixed disk.

4. The two-degree-of-freedom platform for unmanned aerial vehicles according to claim 3, characterized in that: The yaw axis fixed axis rotation angle of the end cover is β, and the pitch axis fixed axis rotation angle of the pitch frame is γ, then: Among them, M1 is the fixed-axis moment of inertia of the yaw axis, M2 is the fixed-axis moment of inertia of the pitch axis, and R Y2 is the radius of the turntable gear, R Z2 is the radius of the meshing part, R Z3 is the radius of the first driving gear.

5. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 4, characterized in that: The gear ratio of the first driving gear and the meshing portion is 1:3, the torque ratio of the first driving gear and the meshing portion is 1:3, the module of the first driving gear and the meshing portion is 2.5, and the torque required by the pitch motor is 6. The two-degree-of-freedom gimbal for an unmanned aerial vehicle according to claim 5, characterized in that: The gear ratio of the second driving gear to the turntable gear is 1:2.5, the torque ratio of the first driving gear to the meshing portion is 1:2.5, the module of the first driving gear and the meshing portion is 2, and the torque required by the pitch motor is 7. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 1, characterized in that: The meshing portion is a quarter gear.

8. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 1, characterized in that: The pitch frame is provided with a speed regulator, which is electrically connected to the pitch motor. The bottom of the pitch frame is provided with an image transmission mounting plate, which is provided with an image transmission module, and the image transmission module is electrically connected to the camera.

9. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 1, characterized in that: A protruding plate is provided at the front end of the pitch frame, the camera is provided on the protruding plate, and an infrared thermal imaging module is provided at the bottom of the protruding plate.

10. The two-degree-of-freedom gimbal for unmanned aerial vehicles according to claim 2, characterized in that: The pitch motor and the rotation motor are both brushless motors.

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