A rotor pitch control device based on the parallel drive of 2-PUU + PSR

Abstract

The present invention provides a rotor pitch control device based on 2-PUU + PSR parallel drive, which includes a 2-PUU + PSR parallel mechanism drive module, a pitch adjustment module, and a rotor shaft drive module; the 2-PUU + PSR parallel mechanism drive module includes a base, a non-rotating ring, and two identical PUU drive kinematic chains and one PSR drive kinematic chain connecting the base and the non-rotating ring. The sliding pairs in the drive kinematic chains are all perpendicular to the base, and the pose movement of the non-rotating ring can be realized; the pitch adjustment module includes a rotating ring, a hub, a pitch link kinematic chain, and a torque arm, which can transfer the movement of the non-rotating ring to the blade; the rotor shaft drive module includes a motor and a rotor shaft, which are used to drive the hub and the rotating ring to move synchronously, thereby realizing rotor pitch control; there is no ball hinge connection between the non-rotating ring and the rotor shaft in the present invention, and it is driven by a 2-PUU + PSR parallel mechanism, which is beneficial to improving the control range of the pitch hinge. The overall structure is symmetrical, simple, and easy to assemble and maintain.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopters, and particularly relates to a rotor pitch control device based on 2-PUU+PSR parallel drive. Background Art

[0002] As the core of the helicopter control system, the rotor pitch control device usually consists of key components such as a drive, a control rod system, and an automatic pitch changer. Its main function is to achieve the collective pitch and cyclic pitch control of the rotor. Therefore, its structure is crucial for the control performance and safety of the helicopter. Generally, a large spherical hinge is used to connect the non-rotating ring and the rotor shaft in the rotor pitch control device. When the blade rotates, the hinge moment received by the blade is transmitted to the rotating ring through the pitch rocker and the pitch pull rod, and part of the radial load is transmitted to the guide tube through the large spherical hinge. Therefore, the service life of the large spherical hinge will directly affect the flight of the helicopter. At the same time, due to the complex structure of the large spherical hinge and the high assembly conditions required for the non-rotating ring, it will increase the complexity of the control device and the manufacturing and maintenance costs. In recent years, Chinese Patent CN2008101559031 sets the actuator on the hub arm to drive the trailing edge flap located on the blade to achieve the pitch change of the blade. Chinese Patent CN201921523236.8 designs a non-inclined disk cyclic pitch device to achieve the control of the rotor. Chinese Patent CN201610362112.0 designs a rotor drive device with good spherical pair force and flexible main rotor swing based on the 2SPS+UPU+SP parallel mechanism. Chinese Patent CN2021102173607 improves the spherical hinge structure in order to improve the connection method and reduce the maintenance and repair costs. Chinese Patent CN2013105594976 uses a hybrid mechanism composed of two parallel mechanisms as the rotor mechanism in order to reduce energy consumption.

[0003] Researchers have improved or innovated the overall or partial structure of the rotor pitch control device in order to achieve the design effect, but there are still certain deficiencies. For example, there is a large spherical hinge in the control device, resulting in a complex structure and affecting the service life cycle of the control device; there is no automatic pitch changer in the control device, but the load-bearing capacity is small and other problems. Therefore, further structural design of the rotor pitch control device is required to solve the problems existing in the prior art. Summary of the Invention

[0004] In order to solve the above deficiencies of the prior art, the present invention proposes a rotor pitch control device based on 2-PUU+PSR parallel drive. This pitch control device has no intermediate large spherical hinge, a symmetric and simple structure, flexible operation, and is easy to assemble and maintain.

[0005] Specifically, the present invention proposes a rotor pitch control device based on 2-PUU+PSR parallel drive, which includes a 2-PUU+PSR parallel mechanism drive module, a pitch adjustment module, and a rotor shaft drive module;

[0006] The 2-PUU+PSR parallel mechanism drive module includes a base, a non-rotating ring, and two PUU drive kinematic chains and one PSR drive kinematic chain with the same structure that connect the base and the non-rotating ring. The two ends of the three drive kinematic chains are respectively connected to the base and the non-rotating ring, and the three connection points on the base and the non-rotating ring are distributed at 120 degrees to each other. The PUU drive kinematic chain sequentially includes a first prismatic pair, a first universal hinge, a first link, and a second universal hinge along the direction from the base to the non-rotating ring. The first universal hinge is arranged between the first prismatic pair and the first end of the first link, and the second universal hinge is arranged between the second end of the first link and the non-rotating ring. The axis of the outer revolute pair of the first universal hinge is parallel to the prismatic pair, and the axis of the outer revolute pair of the second universal hinge faces the center of the non-rotating ring. The PSR drive kinematic chain sequentially includes a second prismatic pair, a spherical pair, a second link, and a revolute pair along the direction from the base to the non-rotating ring. The spherical pair is arranged between the second prismatic pair and the first end of the second link, and the revolute pair is arranged between the second end of the second link and the non-rotating ring. The axis of the revolute pair is parallel to the line connecting the connection points where the two PUU drive kinematic chains are connected to the non-rotating ring. Both the first prismatic pair and the second prismatic pair are perpendicularly and fixedly arranged on the base;

[0007] The pitch adjustment module includes a rotating ring, a hub, a torque arm, and three pitch link kinematic chains with the same structure. The first ends of the three pitch link kinematic chains are respectively connected to the rotating ring through spherical pairs and the connection points are evenly distributed in a circumferential manner. The second ends of the pitch link kinematic chains are connected to the hub through pitch hinges. The first end of the torque arm is connected to the rotating ring by means of a spherical pair, the second end of the torque arm is connected to the torque arm support by means of a revolute pair, and the torque arm support is fixedly connected to the rotor shaft;

[0008] The rotor shaft drive module includes a main shaft motor and a rotor shaft. The first end of the rotor shaft is connected to the main shaft motor, the second end of the rotor shaft is connected to the hub, and the middle of the rotor shaft passes through the central through hole of the non-rotating ring.

[0009] Preferably, the 2-PUU+PSR parallel mechanism drive module can realize the pose adjustment of the rotating ring and the non-rotating ring, and the first prismatic pair and the second prismatic pair in the three PSR drive kinematic chains are both drive pairs.

[0010] Preferably, the first prismatic pair and the second prismatic pair are driven by a servo motor to drive a ball screw linear module to realize the function of the prismatic pair.

[0011] Preferably, the non-rotating ring is directly sleeved outside the rotor shaft, and there is a certain gap between them.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] (1) The rotor pitch control device based on 2-PUU+PSR parallel drive proposed by the present invention simplifies the overall structure of the traditional pitch control device. The parallel drive module does not have an anti-torsion arm branch and does not require a large intermediate ball joint, which is convenient for the processing and maintenance of the overall device, and is beneficial to extending the service life of the overall device, and is more suitable for small unmanned helicopters.

[0014] (2) The present invention uses a 2-PUU+PSR parallel mechanism as the drive module, which has a symmetrical and compact structure, and improves the load to a certain extent compared with the traditional unmanned aircraft without an automatic swashplate.

[0015] (3) Since there is no large intermediate ball joint in the present invention, and a certain gap is provided between the non-rotating ring and the rotor shaft, the attitude adjustment ability of the rotating ring and the non-rotating ring has been greatly improved, which is beneficial to increasing the pitch hinge control range, the overall structure is simple, and the operation is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural diagram of a rotor pitch control device based on 2-PUU+PSR parallel drive;

[0017] Figure 2 is a structural diagram of the pitch adjustment module;

[0018] Figure 3 is a structural diagram of the 2-PUU+PSR parallel mechanism drive module.

[0019] Among them, the main reference numerals are as follows:

[0020] Machine base - 1; Ball screw linear module - 2; PUU drive kinematic chain - 3; PSR drive kinematic chain - 4; First connecting rod - 5; Second connecting rod - 6; Non-rotating ring - 7; Pitch pull rod kinematic chain - 8; Torsion arm - 9; Rotor shaft - 10; Hub - 11; Rotating ring - 12; Blade - 13; Main shaft motor - 14; Servo motor - 15. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Hereinafter, the embodiments of the present invention will be described with reference to the drawings.

[0022] See attached Figures 1 - 3 , a rotor pitch control device based on 2-PUU+PSR parallel drive of the present invention includes a 2-PUU+PSR parallel mechanism drive module, a pitch adjustment module, and a rotor shaft drive module.

[0023] The 2-PUU+PSR parallel mechanism drive module includes a base 1, a non-rotating ring 7, and two structurally identical PUU drive kinematic chains 3 and one PSR drive kinematic chain 4 that connect the base 1 and the non-rotating ring 7. Among them, three symmetrically distributed ball screw linear modules 2 fixedly connected to the base 1 are installed on the base 1, which are driven by a servo motor 15. The three drive kinematic chains are symmetrically arranged in space, and the adjacent end points where they are respectively connected to the base 1 and the non-rotating ring 7 are distributed at 120 degrees. The PUU drive kinematic chain 3 successively includes a first moving pair, a first universal hinge, a first link 5, and a second universal hinge from the base 1 to the non-rotating ring 7. The first moving pair is connected to the first end of the first link 5 through the first universal hinge, and the second end of the first link 5 is connected to the non-rotating ring 7 through the second universal hinge. The axis of the outer rotating pair of the first universal hinge is parallel to the moving pair, and the axis of the outer rotating pair of the second universal hinge points to the center of the non-rotating ring 7. The axes of the inner rotating pairs of the first universal hinge and the second universal hinge are arranged parallel to each other. The PSR drive kinematic chain 4 successively includes a second moving pair, a spherical pair, a second link 6, and a rotating pair from the base 1 to the non-rotating ring 7. The second moving pair is connected to the first end of the second link 6 through the spherical pair, and the second end of the second link 6 is connected to the non-rotating ring 7 through the rotating pair. The axis of the rotating pair is parallel to the line connecting the two connection points where the two PUU drive kinematic chains 3 are connected to the non-rotating ring 7; both the first moving pair and the second moving pair are vertically and fixedly installed on the base 1.

[0024] The pitch adjustment module includes a rotating ring 12, a hub 11, a torque arm 9, and three identical pitch link kinematic chains 8. Among them, the first ends of the three pitch link kinematic chains 8 are connected to the rotating ring 12 through spherical pairs at circumferentially uniform positions, and the second ends of the pitch link kinematic chains 8 are connected to the hub 11 through pitch hinges and are also connected to the blades 13 through bolts; the first end of the torque arm 9 is connected to the rotating ring 12 through a spherical pair, and the second end of the torque arm 9 is connected to the torque arm support through a rotating pair, and the torque arm support is fixedly connected to the rotor shaft 10.

[0025] The rotor shaft drive module includes a main shaft motor 14 and a rotor shaft 10. Among them, the first end of the rotor shaft 10 is connected to the motor, the second end of the rotor shaft 10 is connected to the hub 11, and the middle of the rotor shaft 10 passes through the central through hole of the non-rotating ring 7.

[0026] The 2-PUU+PSR parallel mechanism drive module can realize the pose adjustment of the rotating ring 12 and the non-rotating ring 7. In specific applications, combined with different control modes, the poses of the rotating ring 12 and the non-rotating ring 7 can be changed by controlling the 2-PUU+PSR parallel mechanism drive module.

[0027] The non-rotating ring 7 and the rotating ring 12 are connected by means of a rolling bearing. The non-rotating ring 7 and the rotor shaft 10 are no longer connected by a traditional large ball joint, but are directly sleeved together. A certain gap is reserved between the two. Due to the absence of the intermediate large ball joint and the setting of a certain gap between the non-rotating ring and the rotor shaft, the attitude adjustment ability between the rotating ring and the non-rotating ring has been greatly improved, and the performance of the entire unmanned aerial vehicle has been significantly improved on the basis of simplifying the structure.

[0028] The pitch control is jointly controlled by the 2-PUU+PSR parallel mechanism drive module and the rotor shaft drive module. Based on different control modes, the three moving pairs of the 2-PUU+PSR parallel mechanism are coordinated and controlled. The non-rotating ring 7 realizes the pose movement, and the poses of the non-rotating ring 7 and the rotating ring 12 change accordingly. The movement is transmitted to the blade 13 through the pitch adjustment module. Driven by the rotor shaft 10, the rotating ring 12 and the hub 11 realize the collective pitch and cyclic pitch movements of the blade 13, and finally realize the control of flight postures such as forward and backward, left and right, up and down.

[0029] The working principle of the present invention will be further described below in conjunction with specific embodiments:

[0030] This embodiment provides a rotor pitch control device based on 2-PUU+PSR parallel drive, which includes a 2-PUU+PSR parallel mechanism drive module, a pitch adjustment module and a rotor shaft drive module.

[0031] The 2-PUU+PSR parallel mechanism drive module includes a base 1, a non-rotating ring 7, and two identical PUU drive kinematic chains 3 and one PSR drive kinematic chain 4 connecting the base 1 and the non-rotating ring 7. Three symmetrically distributed ball screw linear modules 2 are installed on the base 1 and fixedly connected to the base 1. The three drive kinematic chains are symmetrically arranged, and the adjacent end points connecting them to the base 1 and the non-rotating ring 7 are distributed at 120 degrees.

[0032] The pitch adjustment module includes a rotating ring 12, a hub 11, a torsion arm 9 and three identical pitch link kinematic chains 8. The first ends of the three pitch link kinematic chains 8 are connected to the rotating ring 12 through spherical joints at circumferentially evenly distributed end points. The second ends of the pitch link kinematic chains 8 are connected to the hub 11 through pitch hinges and are also connected to the blade 13 through bolts. The first end of the torsion arm 9 is connected to the rotating ring 12 through a spherical joint. The second end of the torsion arm 9 is connected to the torsion arm support through a revolute joint, and the torsion arm support is fixedly connected to the rotor shaft 10.

[0033] By coordinately controlling the three driving inputs of the driving module of the 2-PUU+PSR parallel mechanism, the rotating ring 12 and the non-rotating ring 7 achieve position and attitude adjustment. At the same time, the pitch adjustment module further transmits the motion to the blade 13. Driven by the rotor shaft 10, the blade 13 realizes the cyclic pitch motion and the collective pitch motion, and further enables the unmanned helicopter to complete motions such as ascending, descending, and advancing. For example, when the magnitudes of the three driving inputs are the same, the rotating ring 12 and the non-rotating ring 7 ascend or descend, the blade 13 realizes the collective pitch motion, and the unmanned helicopter ascends or descends.

[0034] When the driving inputs are inconsistent, the rotating ring 12 and the non-rotating ring 7 tilt, the blade 13 realizes the cyclic pitch motion, and the helicopter moves forward / backward, left / right.

[0035] The embodiments described above are only descriptions of 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 solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A rotor pitch control device based on 2-PUU + PSR parallel drive, characterized in that: It includes a 2-PUU+PSR parallel mechanism drive module, a pitch adjustment module, and a rotor shaft drive module; The 2-PUU+PSR parallel mechanism drive module includes a base, a non-rotating ring, and two structurally identical PUU drive kinematic chains and one PSR drive kinematic chain connecting the base and the non-rotating ring. The two ends of the three drive kinematic chains are respectively connected to the base and the non-rotating ring. The three connection points on the base and the non-rotating ring are distributed at 120 degrees to each other. The PUU drive kinematic chain sequentially includes a first prismatic pair, a first universal joint, a first link, and a second universal joint along the direction from the base to the non-rotating ring. The first universal joint is arranged between the first prismatic pair and the first end of the first link. The second universal joint is arranged between the second end of the first link and the non-rotating ring. The outer revolute pair axis of the first universal joint is parallel to the prismatic pair. The outer revolute pair axis of the second universal joint faces the center of the non-rotating ring. The PSR drive kinematic chain sequentially includes a second prismatic pair, a spherical pair, a second link, and a revolute pair along the direction from the base to the non-rotating ring. The spherical pair is arranged between the second prismatic pair and the first end of the second link. The revolute pair is arranged between the second end of the second link and the non-rotating ring. The revolute pair axis is parallel to the line connecting the connection points where the two PUU drive kinematic chains are connected to the non-rotating ring. The first prismatic pair and the second prismatic pair are both vertically and fixedly arranged on the base; The pitch adjustment module includes a rotating ring, a hub, a torque arm, and three pitch link kinematic chains. The three pitch link kinematic chains are structurally identical. The first ends of the three pitch link kinematic chains are respectively connected to the rotating ring through spherical pairs and the connection points are evenly distributed in a circle. The second ends of the pitch link kinematic chains are connected to the hub through pitch hinges. The first end of the torque arm is connected to the rotating ring by means of a spherical pair. The second end of the torque arm is connected to the torque arm support by means of a revolute pair. The torque arm support is fixedly connected to the rotor shaft; The rotor shaft drive module includes a main shaft motor and a rotor shaft. The first end of the rotor shaft is connected to the main shaft motor. The second end of the rotor shaft is connected to the hub. The middle of the rotor shaft passes through the central through hole of the non-rotating ring.

2. The variable pitch control device for a rotor based on 2-PUU + PSR parallel drive according to claim 1, characterized in that: The 2-PUU+PSR parallel mechanism drive module can realize the pose movement of the non-rotating ring. The first prismatic pair and the second prismatic pair in the three drive kinematic chains are both drive pairs.

3. A variable pitch control device for a rotor based on 2-PUU + PSR parallel drive according to claim 1, characterized in that: The first prismatic pair and the second prismatic pair are driven by a servo motor to drive a ball screw linear module to realize the function of the prismatic pair.

4. A variable pitch control device for a rotor based on 2-PUU + PSR parallel drive according to claim 1, characterized in that, The non-rotating ring is sleeved outside the rotor shaft and there is a certain gap between them.

Images