A rotor control mechanism for an inspection unmanned helicopter

Abstract

The present invention provides a rotor control mechanism for an inspection unmanned helicopter, which includes an RRS+RRU+RSS parallel mechanism, a blade pitch change component, and a rotor main shaft drive component. The RRS+RRU+RSS parallel mechanism includes a base, a non-rotating ring, and an RRS drive branch, an RRU drive branch, and an RSS drive branch. One end of the three drive branches is connected to the base through a revolute pair, and the other ends of the RRS and RSS drive branches are connected to the non-rotating ring through a spherical pair. The other end of the RRU drive branch is connected to the non-rotating ring through a universal hinge. The middle of the non-rotating ring is a through hole and is provided with a groove; the rotating ring and the non-rotating ring are connected by a bearing, and the rotor main shaft passes through the non-rotating ring. The RRS+RRU+RSS parallel mechanism of the present invention realizes the pose transformation of the non-rotating ring, and the blade pitch change component changes the size of the pitch angle. The present invention abandons the traditional anti-torsion arm branch and the spherical hinge structure between the non-rotating ring and the rotor main shaft, improves the attitude adjustment ability of the rotating ring and the non-rotating ring, simplifies the mechanical structure, and is convenient for processing, installation and later maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopters, and particularly relates to a rotor control mechanism for an inspection unmanned helicopter. Background Art

[0002] As an important application field of unmanned aerial vehicles (UAVs), inspection has been widely applied to inspection scenarios such as power grids, pipelines, agriculture, and forestry. Currently, inspection UAVs are mainly divided into two categories: multi-rotor UAVs and unmanned helicopters. Due to their structural particularity, the former often has weak wind resistance and load-bearing capacity, making it unfavorable for use in mountainous areas and other places; the latter makes up for the deficiencies of multi-rotor UAVs in terms of wind resistance and load, enabling it to shine in inspections, which mainly benefits from the crucial role played by the rotor control mechanism. The rotor control mechanism generally includes important components such as a non-rotating ring, anti-torsion arm, rotating ring, ball joint, torsion arm, pitch link, etc. In traditional rotor control mechanisms, there are three hydraulic booster or servo drive branches connecting the non-rotating ring and the base, and a non-rotating ring is connected to the rotor main shaft through a ball joint, so as to realize the movement of the rotating ring and the non-rotating part along the rotor main shaft and attitude adjustment. For example, the rotor drive system designed in Chinese Patent CN2013105028653, a helicopter control mechanism disclosed in Chinese Patent CN2014105886911, and a helicopter mechanical control system disclosed in Chinese Patent 2010102067915 all adopt this structure. Simplifying and lightweighting the rotor control mechanism is the direction and goal pursued by experts and scholars in the fields of helicopters and mechanism science. In order to simplify the structure, a single-rotor helicopter rotor mechanism invented in Chinese Patent CN 2008102190876 uses a directional track to replace the anti-torsion arm branch; a rotor pitch-changing device invented in Chinese Patent CN 2020101131655 uses the deformation of a flexible beam to realize the flapping, pitching, and pitch-changing movements of the blade, which has the advantages of simple structure and convenient maintenance.

[0003] The above patents provide reasonable and effective technical solutions, but there are still some problems. For example, the complex ball joint structure will increase the manufacturing cost and bring many inconveniences to assembly and later maintenance. At the same time, due to the existence of the intermediate ball joint, to a certain extent, it limits the operating range of the pitch angle. Summary of the Invention

[0004] In order to solve the above deficiencies of the prior art, a rotor control mechanism for an inspection unmanned helicopter with a simple structure, a large pitch angle range, and convenient control is provided.

[0005] A rotor control mechanism for an inspection unmanned helicopter provided by the present invention includes an RRS+RRU+RSS parallel mechanism, a blade pitch-changing assembly, and a rotor main shaft drive assembly.

[0006] The RRS+RRU+RSS parallel mechanism includes a base, a non-rotating ring, and three driving branches. The three driving branches are the RRS driving branch, the RRU driving branch, and the RSS driving branch respectively. The first ends of the three driving branches are connected to the base through revolute pairs. The second ends of the RRS driving branch and the RSS driving branch are connected to the non-rotating ring through spherical pairs. The second end of the RRU driving branch is connected to the non-rotating ring through a universal hinge. The center of the non-rotating ring is a through hole.

[0007] The axes of the revolute pairs connected to the base in the RRS driving branch and the RSS driving branch are parallel to each other and perpendicular to the axis of the revolute pair connected to the base in the RRU driving branch. The outer axis of the universal hinge connected to the non-rotating ring in the RRU driving branch is perpendicular to the line connecting the two end points where the RRS driving branch and the RSS driving branch are connected to the non-rotating ring.

[0008] The blade pitch change assembly includes a pitch change link, a pitch change blade grip, a torque arm, a rotating ring, a blade, and a hub. The rotating ring is provided with three connection points. Among them, the first connection point and the second connection point are symmetrically arranged. The first connection point and the second connection point are respectively connected to the first ends of a pitch change link. The third connection point is connected to the first end of the torque arm. The second end of the pitch change link is connected to the first end of the pitch change blade grip. The second end of the torque arm is connected to the rotor main shaft through a torque arm collar. The second end of the pitch change blade grip is connected to the hub.

[0009] Preferably, the rotor main shaft drive assembly includes a motor, a pulley, a synchronous belt, and a rotor main shaft.

[0010] Preferably, the rotating ring and the non-rotating ring are connected by means of a bearing. The outer ring of the bearing is connected to the inner side of the groove of the non-rotating ring, and the inner ring of the bearing is connected to the rotating ring.

[0011] Preferably, a bushing is fixedly provided on the base, and both ends of the bushing are connected to the rotor main shaft through bearings.

[0012] Preferably, the revolute pairs connecting the three driving branches to the base are all driven by servos.

[0013] Preferably, the non-rotating ring is provided with a groove for installing a bearing.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] (1) The rotor control mechanism for the inspection unmanned helicopter proposed by the present invention simplifies the connection method between the traditional non-rotating ring and the base. Only by using the RRS driving branch, the RRU driving branch, and the RSS driving branch can the two rotations and one translation motion of the non-rotating ring be realized, and the rotation axis is close to the non-rotating ring, which can improve the pose adjustment function of the non-rotating ring and the rotating ring, and the structure is more simplified.

[0016] (2) The parallel drive mechanism proposed by the present invention has a continuous rotating shaft, which is convenient for kinematic calibration and control, and avoids complex control work.

[0017] (3) The present invention abandons the ball joint between the rotating ring and the rotor main shaft. On the one hand, it increases the attitude change ability of the rotating ring and the rotating ring, improves the control range of the pitch angle, and on the other hand, it improves the overall service life of the rotor control mechanism to a certain extent.

[0018] (4) The structure of the present invention simplifies the original complex pitch control mechanism, reduces the processing and manufacturing cost and the difficulty of assembly and maintenance, and can be used for inspection unmanned helicopters. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an isometric structural view of the rotor control mechanism for an inspection unmanned helicopter of the present invention;

[0020] Figure 2 is an isometric structural view of the rotor control mechanism without blades for an inspection unmanned helicopter of the present invention;

[0021] Figure 3 is a structural view of the main shaft drive assembly in the rotor control mechanism for an inspection unmanned helicopter of the present invention;

[0022] Figure 4 is a structural view of the RRS+RRU+RSS parallel mechanism in the rotor control mechanism for an inspection unmanned helicopter of the present invention;

[0023] Figure 5 is a structural view of the blade pitch change assembly in the rotor control mechanism for an inspection unmanned helicopter of the present invention.

[0024] The main reference numerals are as follows:

[0025] 1 - blade, 2 - hub, 3 - pitch change paddle clip, 4 - rotor main shaft, 5 - bushing, 6 - motor, 7 - motor shaft pulley, 8 - main shaft pulley, 9 - synchronous belt, 10 - pitch change connecting rod, 11 - torque arm, 12 - non-rotating ring, 13 - rotating ring, 14 - torque arm collar, 15 - bearing, 16 - RRS drive branch, 17 - RRU drive branch, 18 - RSS drive branch, 19 - pitch change cross shaft, 20 - base, 21 - servo. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0027] A rotor control mechanism for an inspection unmanned helicopter according to the present invention, as Figures 1 - 5As shown, it includes an RRS+RRU+RSS parallel mechanism, a blade pitch-changing assembly, and a rotor main shaft drive assembly.

[0028] The RRS+RRU+RSS parallel mechanism includes a base 20, a non-rotating ring 12, and three symmetrically arranged drive branches, namely the RRS drive branch 16, the RRU drive branch 17, and the RSS drive branch 18. The first ends of the three drive branches are connected to the base 20 through revolute joints. The second ends of the RRS drive branch 16 and the RSS drive branch 18 are connected to the non-rotating ring 12 through spherical joints. The other end of the RRU drive branch 17 is connected to the non-rotating ring 12 through a universal hinge. There is a through hole in the middle of the non-rotating ring 12 and a groove for installing a bearing 15.

[0029] The axes of the revolute joints of the RRS drive branch 16 and the RSS drive branch 18 connected to the base 20 are parallel, and are perpendicular to the axis of the revolute joint of the RRU drive branch 17 connected to the base 20. The outer axis of the universal hinge of the RRU drive branch 17 connected to the non-rotating ring 12 is perpendicular to the connecting line of the endpoints of the RRS drive branch 16 and the RSS drive branch 18 connected to the non-rotating ring 12.

[0030] The blade pitch-changing assembly includes a pitch-changing link 10, a pitch-changing blade grip 3, a torque arm 11, a rotating ring 13, a blade 1, and a hub 2. There are three connection points on the rotating ring 13. The first connection point and the second connection point are symmetrically arranged. The two symmetric first connection points and second connection points are respectively connected to the first end of a pitch-changing link 10. The third connection point is connected to the first end of the torque arm 11. The second end of the pitch-changing link 10 is connected to the first end of the pitch-changing blade grip 3. The second end of the torque arm 11 is connected to the rotor main shaft 4 through a torque arm collar 14. The second end of the pitch-changing blade grip 3 is connected to the hub 2. The blade 1 is connected to the pitch-changing blade grip 3 through bolts.

[0031] The non-rotating ring 12 and the rotating ring 13 are connected by means of a bearing 15. The outer ring of the bearing 15 is connected to the inner side of the groove of the non-rotating ring 12, and the inner ring of the bearing 15 is connected to the rotating ring 13. In this embodiment, the bearing 15 is a rolling bearing.

[0032] The rotor main shaft drive assembly includes a motor 6, a motor shaft pulley 7, a main shaft pulley 8, a synchronous belt 9, and a rotor main shaft 4. The lower part of the rotor main shaft 4 is connected to the main shaft pulley 8. The middle of the rotor main shaft 4 directly passes through the non-rotating ring 12. There is no intermediate spherical hinge connection between the rotor main shaft 4 and the non-rotating ring 12. The upper part of the rotor main shaft 4 is fixedly connected to the hub 2. A bushing 5 is fixedly connected to the base 20, and both ends of its interior are connected to the rotor main shaft 4 through bearings. A pitch-changing cross shaft 19 passes through the upper hollow part of the hub 2. The pitch-changing blade grip 3 is installed on the pitch-changing cross shaft 19 through three bearings.

[0033] In this embodiment, the revolute pairs connecting the RRS drive branch 16, the RRU drive branch 17, the RSS drive branch 18 and the base 20 are all driven by the servo 21. In other embodiments, the revolute pairs of the three drive branches can also be driven by other drive devices.

[0034] The working principle of the present invention will be further described below in conjunction with the embodiments:

[0035] During operation, the pitch control is jointly controlled by the RRS+RRU+RSS parallel mechanism and the rotor main shaft drive assembly to change the flight attitude. Based on different control modes, by coordinating the control of the three drive inputs of the RRS+RRU+RSS parallel mechanism, the non-rotating ring 12 realizes a two-rotation and one-translation motion, thereby regulating the position and attitude of the rotating ring 13 and the non-rotating ring 12. The motion is transmitted to the blade 1 through the blade pitch assembly. Driven by the rotor main shaft 4, the rotating ring 13 and the hub 2 realize the collective pitch and cyclic pitch motions of the blade 1, and finally realize the control of flight attitudes such as forward and backward, left and right, up and down.

[0036] The rotor control mechanism for the inspection unmanned helicopter of the present invention simplifies the connection mode between the traditional non-rotating ring and the base. Only by using the RRS drive branch, the RRU drive branch and the RSS drive branch can the two-rotation and one-translation motion of the non-rotating ring be realized, and the rotation axis is close to the non-rotating ring, which can improve the pose adjustment function of the non-rotating ring and the rotating ring. The structure is more simplified and the control is more convenient and accurate. The control of flight attitudes such as forward and backward, left and right, up and down of the unmanned aerial vehicle is realized through the different drives of the three branches of the RRS drive branch, the RRU drive branch and the RSS drive branch.

[0037] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A rotor control mechanism for an unmanned helicopter for inspection, characterized in that: It includes an RRS+RRU+RSS parallel mechanism, a blade pitch-changing assembly, and a rotor main shaft drive assembly. The RRS+RRU+RSS parallel mechanism includes a base, a non-rotating ring, and three drive branches, namely the RRS drive branch, the RRU drive branch, and the RSS drive branch. The first ends of the three drive branches are connected to the base through revolute pairs. The second ends of the RRS drive branch and the RSS drive branch are connected to the non-rotating ring through spherical pairs. The second end of the RRU drive branch is connected to the non-rotating ring through a universal hinge. The center of the non-rotating ring is a through hole. The axes of the revolute pairs of the RRS drive branch and the RSS drive branch connected to the base are parallel to each other and perpendicular to the axis of the revolute pair of the RRU drive branch connected to the base. The outer axis of the universal hinge of the RRU drive branch connected to the non-rotating ring is perpendicular to the line connecting the two endpoints of the RRS drive branch and the RSS drive branch connected to the non-rotating ring. The blade pitch-changing assembly includes pitch-changing linkages, pitch-changing blade clamps, torque arms, a rotating ring, blades, and a hub. The rotating ring is provided with three connection points. Among them, the first connection point and the second connection point are symmetrically arranged. The first connection point and the second connection point are respectively connected to the first ends of a pitch-changing linkage. The third connection point is connected to the first end of the torque arm. The second end of the pitch-changing linkage is connected to the first end of the pitch-changing blade clamp. The second end of the torque arm is connected to the rotor main shaft through a torque arm collar. The second end of the pitch-changing blade clamp is connected to the hub.

2. The rotor control mechanism for the unmanned helicopter used for patrol inspection according to claim 1, wherein: The rotor main shaft drive assembly includes a motor, a pulley, a synchronous belt, and a rotor main shaft.

3. The rotor control mechanism for the unmanned helicopter used for inspection tours according to claim 1, characterized in that: The rotating ring and the non-rotating ring are connected by means of a bearing. The outer ring of the bearing is connected to the inner side of the groove of the non-rotating ring, and the inner ring of the bearing is connected to the rotating ring.

4. The rotor control mechanism for the unmanned helicopter used for patrol inspection according to claim 1, characterized in that: A bushing is fixedly provided on the base. The two ends inside the bushing are connected to the rotor main shaft through bearings.

5. The rotor control mechanism for the inspection unmanned helicopter according to claim 1, wherein: The revolute pairs of the three drive branches connected to the base are all driven by servos.

6. The rotor control mechanism for the unmanned helicopter used for patrol inspection according to claim 1, characterized in that: The non-rotating ring is provided with a groove for installing a bearing.

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