Low-frequency vibration isolation transition connecting device

Abstract

The invention belongs to the field of vibration isolation structures, and particularly discloses a low-frequency vibration isolation transition connecting device which comprises a vibration isolation component and a rotating component, and the vibration isolation component comprises a support assembly, a hinge assembly and an elastic assembly; the support assembly comprises a first support and a second support, each hinge assembly comprises a first hinge and a second hinge, the first supports, the first hinges, the second hinges and the second supports are sequentially connected through shaft pins from top to bottom, and the hinge assemblies are arranged in the circumferential direction. The three groups of elastic components at the upper, middle and lower parts are respectively positioned at the upper side of the first hinge, the joint of the first hinge and the second hinge and the lower side of the second hinge; each group of elastic components comprises a fixed node and a plurality of elastic elements, one side of each elastic element is connected with the corresponding hinge through a shaft pin, and the other side of each elastic element is connected with the fixed node; one end of the rotating part is connected with the second support, and the other end is used for mounting a load. Vibration of the unmanned helicopter body can be effectively isolated, and the imaging quality of the photoelectric load is improved.

Description

Technical Field

[0001] This invention belongs to the field of vibration isolation structures, and more specifically, relates to a low-frequency vibration isolation transition connection device. Background Technology

[0002] With the development of the marine economy and the increasing demand for the protection of maritime rights, unmanned helicopters equipped with electro-optical payloads are widely used in maritime reconnaissance and inspection due to their advantages such as high maneuverability, long flight time, and diverse payloads. They can overcome challenges such as vast sea areas, complex environments, and high costs associated with manual inspections. By integrating high-definition electro-optical pods and radar systems, they can efficiently perform tasks such as maritime law enforcement, illegal fishing, and smuggling monitoring. In the inspection of offshore oil platforms, wind farms, and cross-sea bridges, they can achieve close-range, low-risk detection, replacing traditional manned helicopter operations. In marine environmental monitoring and emergency response, they can quickly reach the scene and transmit real-time images of oil spills, pollution, or search and rescue targets, supporting scientific decision-making and becoming a key force in building a three-dimensional maritime monitoring system.

[0003] Compared to fixed-wing or multi-rotor aircraft, helicopter platforms generally suffer from large low-frequency vibrations and poor stability during flight, especially in maritime environments where frequent gusts and complex airflows exacerbate airframe disturbances. These vibrations and airflow disturbances are transmitted through the fuselage structure to the optoelectronic payload, easily leading to blurred, jittery, or out-of-focus images, severely impacting target identification, tracking, and high-definition imaging capabilities. Under adverse conditions such as high sea states, strong winds, rain, and fog, the periodic interference from rotor airflow further exacerbates the challenges to the imaging quality and stability of the optoelectronic system. Therefore, effectively suppressing low-frequency vibrations and improving image stabilization and clarity under dynamic sea conditions has become a core technical challenge that unmanned helicopters urgently need to overcome to perform maritime reconnaissance, surveillance, and precision inspection missions. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a low-frequency vibration isolation transition connection device, the purpose of which is to suppress low-frequency vibration of unmanned helicopters and improve the imaging quality of their photoelectric payloads.

[0005] To achieve the above objectives, the present invention proposes a low-frequency vibration isolation transition connection device, comprising a vibration isolation component and a rotating component, wherein: The vibration isolation component includes a support assembly, a hinge assembly, and an elastic assembly; The support assembly includes a first support and a second support. Each set of hinge assemblies includes a first hinge and a second hinge. The first support, the first hinge, the second hinge, and the second support are connected sequentially from top to bottom by a pivot pin. The sets of hinge assemblies are arranged circumferentially and form a vibration isolation cavity with the support assembly. The elastic components are disposed in the vibration isolation cavity. The three sets of elastic components in the upper, middle and lower parts are located on the upper side of the first hinge, at the connection between the first hinge and the second hinge, and on the lower side of the second hinge, respectively. Each set of elastic components includes a fixed node and several elastic elements. One side of each elastic element is connected to the corresponding hinge through a pin, and the other side is connected to the fixed node. One end of the rotating component is connected to the second support, and the other end is used to install the load.

[0006] As a further preferred method, the stiffness of the three sets of elastic components is determined as follows: The stiffness of three sets of elastic components is preset; an equivalent mass block with the same mass as the photoelectric load is installed on the rotating part; the first support is installed on the test bench to simulate the real vibration condition of the unmanned helicopter for excitation; and the stiffness of the elastic components is corrected for the first time based on the vibration isolation effect. The stiffness of the elastic component was modified in the first step. An equivalent mass block with the same mass as the photoelectric load was installed on the rotating part. The device was mounted on an unmanned helicopter platform for flight testing. Based on the vibration isolation effect, the stiffness of the elastic component was modified in the second step. The elastic component stiffness was modified a second time. An optoelectronic load was installed on the rotating part, and the device was mounted on an unmanned helicopter platform for flight testing. Based on the actual flight imaging quality of the optoelectronic load, the elastic component stiffness was modified a third time and used as the final stiffness of the elastic component.

[0007] As a further preferred embodiment, the stiffness of the three sets of elastic components is preset, specifically: the stiffness of each elastic element in the central elastic component is preset to a certain value. E 1. The stiffness of each elastic element in the upper and lower elastic components is preset to be... E 2; E 1=k1·Mg· l 1· l 2 / L1 / L2 / L2 E 2 = k2·Mg·L1·L2 / l 1 / l 2 / l 2 In the formula, M is the load mass, g is the gravitational acceleration, and L1 and L2 are the outer arm lengths of the first and second hinges, respectively. l 1. l 2 represents the inner arm lengths of the first and second hinges, respectively; k1 and k2 are correlation coefficients, k1 = f1(α, β, n, Mg, L1, ... l 1), k2=f2 (α, β, n, Mg, L2, l2) f1 and f2 represent dimensionless functions, α is the angle formed by the first hinge and the central plane, β is the angle formed by the second hinge and the central plane, and n is the number of elastic elements in a set of elastic components; the elastic elements in the same elastic component are located in the same horizontal plane, and the central plane refers to the plane where the middle elastic component is located.

[0008] As a further preferred embodiment, the upper side of the first hinge is provided with a first pin and a second pin, which are respectively connected to the first support and the upper elastic component; the first hinge and the second hinge are connected by a third pin, which is also connected to the middle elastic component; the lower side of the second hinge is provided with a fourth pin and a fifth pin, which are respectively connected to the lower elastic component and the second support.

[0009] As a further preferred embodiment, the elastic element is a spring, a rubber rod, an air strut, or a viscous strut.

[0010] As a further preferred embodiment, the fixed node is a ring or a disc.

[0011] As a further preferred embodiment, the number of hinge components is 2 to 6 sets.

[0012] As a further preferred embodiment, the support assembly and hinge assembly are made of aluminum alloy, titanium alloy, carbon fiber composite material or PEEK engineering plastic.

[0013] As a further preferred embodiment, the rotating component includes a shaft assembly and a motor assembly. The shaft assembly includes a first shaft, a second shaft, and a third shaft connected in sequence. The upper end of the first shaft is connected to the second support via the motor assembly, and both ends of the second shaft are connected to the lower end of the first shaft and the third shaft via the motor assembly, respectively. The first shaft, the second shaft, and the third shaft are used to realize vertical, horizontal, and longitudinal rotation, respectively.

[0014] As a further preferred embodiment, the shaft assembly is made of aluminum alloy, carbon fiber composite material or PEEK engineering plastic.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. This invention employs multiple sets of elastic components for spatial layout, combined with a hinge structure to construct a high-efficiency vibration isolation device, and sets fixed nodes in the elastic components, saving space while uniformly distributing multiple elastic elements; enabling the device to meet the requirements of photoelectric load bearing while achieving minimal stiffness during movement, thereby effectively isolating low-frequency vibrations of the unmanned helicopter body, achieving vibration suppression in the frequency range of 0.5~20 Hz, and significantly improving the imaging quality of the photoelectric load.

[0016] 2. This invention further employs a method combining theoretical analysis and experimental verification. Through experiments, the stiffness design parameters of the device's elastic elements are gradually corrected to accurately isolate the vibration load transmitted by the unmanned helicopter body and effectively improve the imaging quality of the photoelectric load. Attached Figure Description

[0017] Figure 1 This is a front view of the low-frequency vibration isolation transition connection device according to an embodiment of the present invention; Figure 2 This is a top view of the low-frequency vibration isolation transition connection device according to an embodiment of the present invention.

[0018] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-first support, 2-second support, 3-first hinge, 4-second hinge, 5-first pivot, 6-second pivot, 7-third pivot, 8-elastic component. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] This invention provides a low-frequency vibration isolation transition connection device, such as... Figure 1 and Figure 2 As shown, it includes vibration isolation components and rotating components, wherein: The vibration isolation component is disposed on one side of the transition connection device and includes a support assembly, a hinge assembly, and an elastic assembly, wherein: The support assembly includes a first support 1 and a second support 2 respectively disposed at the upper and lower parts. The first support 1 is mainly used for the connection between the transition connection device and the external device, and is preferably connected and fixed by bolts or screws. The second support 2 is mainly used for the connection between the vibration isolation component and the rotating component, and is preferably connected and fixed by bolts or screws.

[0021] Furthermore, the materials for the first support 1 and the second support 2 can be aluminum alloy, titanium alloy, carbon fiber composite or PEEK engineering plastic; preferably, aluminum alloy is selected.

[0022] The hinge assembly is located in the middle of the vibration isolation component, including a first hinge 3 and a second hinge 4 arranged vertically. The first hinge 3 and the second hinge 4 are connected by a third pin. The upper side of the first hinge 3 is connected to the first support 1 by a first pin, and the lower side of the second hinge 4 is connected to the second support 2 by a fifth pin, allowing the first hinge 3 and the second hinge 4 to rotate freely around the pins. In addition to connecting to the first and second supports, a second pin and a fourth pin are respectively provided on the upper side of the first hinge 3 and the lower side of the second hinge 4, and there are fixed installation positions between the pins for connecting to the intermediate elastic element.

[0023] Furthermore, there are 2 to 6 hinge assemblies, evenly distributed along the central radial direction, preferably 3 assemblies.

[0024] Furthermore, the hinge assembly material can be aluminum alloy, titanium alloy, carbon fiber composite or PEEK engineering plastic; preferably, PEEK engineering plastic material is selected.

[0025] The elastic component 8 is disposed in the inner cavity of the vibration isolation component. The three sets of elastic components in the upper, middle and lower parts are located on the upper side of the first hinge, the connection between the first hinge and the second hinge and the lower side of the second hinge, respectively, corresponding to the second axle pin, the third axle pin and the fourth axle pin. Each set of elastic components includes a fixed node and several elastic elements. One side of each elastic element is connected to the hinge through the corresponding axle pin, and the other side converges at the center in the horizontal plane and is connected to the fixed node. The number of elastic elements in each set of elastic components is equal to the number of hinge components.

[0026] Furthermore, the elastic component can be a spring component, a rubber component, an air strut component, or a viscous strut component, with a spring component being preferred; the fixing node can be a ring or a disc, with a ring shape being preferred.

[0027] The rotating component is mounted on the other side of the transition connection device and includes a rotating shaft assembly, a motor assembly, and sensing hardware, wherein: The rotating shaft assembly includes a first rotating shaft 5, a second rotating shaft 6, and a third rotating shaft 7. The second support 2, the first rotating shaft 5, the second rotating shaft 6, and the third rotating shaft 7 are all connected sequentially via a motor assembly. The first rotating shaft 5, the second rotating shaft 6, and the third rotating shaft 7 are used to realize rotation in the X, Y, and Z directions in a spatial rectangular coordinate system, respectively. The third rotating shaft 7 is equipped with sensing hardware and has a reserved interface for external photoelectric loads.

[0028] Specifically, the first rotating shaft and the second support are connected via a motor assembly. One side is mounted on the mounting bracket of the motor assembly, and the other side is mounted on the output shaft of the motor assembly. Control commands can control the rotation angle and angular velocity of the first and second rotating shafts, allowing them to rotate in the vertical direction. Furthermore, the motor assembly is a joint motor module. The first and second rotating shafts are also connected via a motor assembly, with one side mounted on the mounting bracket and the other side mounted on the output shaft. Control commands can control the rotation angle and angular velocity of the first and second rotating shafts, allowing them to rotate in the lateral direction. The second and third rotating shafts are also connected via a motor assembly, with one side mounted on the mounting bracket and the other side mounted on the output shaft. Control commands can control the rotation angle and angular velocity of the second and third rotating shafts, allowing them to rotate in the longitudinal direction. The sensing hardware can detect the three translational velocities and accelerations, and the three rotational angular velocities and angular accelerations of the components mounted on the third rotating shaft platform.

[0029] Furthermore, the pivot assembly may be made of aluminum alloy, carbon fiber composite material or PEEK engineering plastic; preferably, it is made of PEEK engineering plastic material.

[0030] Furthermore, this invention provides a method for determining the stiffness of each elastic component, as detailed below: (1) Calculation of theoretical value (i.e. preset value) of stiffness of elastic component: The stiffness of each elastic element in the central elastic assembly is set to... E 1. Its linear relationship with the length of the hinge connecting arm is as follows: E 1=k1·Mg· l 1· l 2 / L1 / L2 / L2 The upper and lower elastic components have the same stiffness, with the stiffness of each elastic element set to... E 2. Its linear relationship with the length of the hinge connecting arm is as follows: E 2 = k2·Mg·L1·L2 / l 1 / l 2 / l 2 In the formula, M is the load mass; g is the acceleration due to gravity; L1 is the length of the outer arm of the first hinge. l L1 represents the inner arm length of the first hinge; L2 represents the outer arm length of the second hinge. l 2 represents the inner arm length of the second hinge; k1 and k2 are configurable correlation coefficients, specifically related to the angle formed by the first hinge, the second hinge, and the center plane, as well as the number of component arrays. k1=f1(α,β,n,Mg,L1,l 1) k2=f2(α,β,n,Mg,L2, l 2) In the formula, α is the angle formed by the first hinge and the central plane, β is the angle formed by the second hinge and the central plane, and the central plane refers to the plane where the central elastic component is located; n is the number of elastic elements in a set of elastic components, that is, the number of hinge components; f1 and f2 represent dimensionless functions, which can be determined according to the mechanical properties of the material and the geometric relationship of the structure.

[0031] For example, α= , β= n=2, L1= L2, l 1= l 2; We can obtain k1= k2= .

[0032] (2) Further correction of the stiffness of the elastic component includes the following steps: (2.1) The stiffness of the elastic element in the middle elastic component is preset to be E 1. The stiffness of the elastic elements in the upper and lower elastic components is preset to be... E 2. An equivalent mass block is set on the third rotating platform to match the mass properties of the actual mounted photoelectric load. The first support is installed on the test bench to simulate the actual vibration conditions of the unmanned helicopter. Excitation is applied to its upper part, and the stiffness of the elastic element is corrected based on the measured vibration isolation effect. The correction factor is denoted as k. 3-1 k 3-2 ; (2.2) The stiffness of the elastic element in the middle elastic component is preset to be E 1·k 3-1 The stiffness of the elastic elements in the upper and lower elastic components is preset to be... E 2·k 3-2 Based on the aforementioned test product, it was mounted on an unmanned helicopter platform and flight tests were conducted under different operating conditions. The vibration isolation effect of the device was measured based on actual flight data, and the stiffness of the elastic element was further corrected. The correction factor is denoted as k. 4-1 k 4-2 ; (2.3) The stiffness of the elastic element in the middle elastic component is preset to be E 1·k 3-1 ·k 4-1 The stiffness of the elastic elements in the upper and lower elastic components is preset to be... E 2·k 3-2 ·k 4-2The actual photoelectric payload was installed on the third rotating platform, and then the entire device was mounted on the unmanned helicopter platform. Flight tests were conducted under different operating conditions. Based on the actual flight imaging quality, the vibration isolation effect of the device was measured, and the stiffness of the elastic elements was corrected again. The correction factor is denoted as k. 5-1 k 5-2 ; (2.4) Based on the previous calculation results, the final stiffness of the elastic element is determined using the following formula: E 1实 =k 3-1 ·k 4-1 ·k 5-1 ·E1, E 2实 = k 3-2 ·k 4-2 ·k 5-2 ·E2.

[0033] The device of this invention can achieve vibration suppression in the frequency range of 0.5~20Hz (especially 0.5~10Hz), which is particularly suitable for unmanned helicopter reconnaissance and inspection. It can also be applied to other UAV reconnaissance or inspection, and can be extended to the field of low-frequency vibration imaging of optoelectronic payloads, improving the imaging quality of such optoelectronic payloads, expanding their application scenarios, and improving their practicality.

[0034] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low frequency vibration isolation transition coupling device, characterized by, The vibration isolation device comprises a vibration isolation component and a rotating component, wherein: The vibration isolation component comprises a support assembly, a hinge assembly and an elastic assembly; The support assembly comprises a first support and a second support, and each hinge assembly comprises a first hinge and a second hinge, which are connected by shaft pins from top to bottom; a plurality of hinge assemblies are arranged circumferentially and form a vibration isolation cavity with the support assembly; The elastic assembly is arranged in the vibration isolation cavity, and three groups of elastic assemblies are arranged at the upper side of the first hinge, the connection between the first hinge and the second hinge and the lower side of the second hinge; each group of elastic assemblies comprises a fixed node and a plurality of elastic elements, one side of each elastic element is connected to the corresponding hinge by a shaft pin, and the other side is connected to the fixed node; One end of the rotating component is connected to the second support, and the other end is used for mounting a load.

2. The low frequency isolation transition connection apparatus of claim 1, wherein, The determination method of the stiffness of the three groups of elastic assemblies is as follows: The stiffness of the three groups of elastic assemblies is preset; an equivalent mass block consistent with the photoelectric load mass is mounted on the rotating component, the first support is mounted on a test bench, a real vibration working condition of the unmanned helicopter is simulated for excitation, the stiffness of the elastic assembly is corrected for the first time according to the vibration isolation effect; The stiffness of the elastic assembly corrected for the first time is adopted; an equivalent mass block consistent with the photoelectric load mass is mounted on the rotating component, the device is mounted on the unmanned helicopter platform for flight test, the stiffness of the elastic assembly is corrected for the second time according to the vibration isolation effect; The stiffness of the elastic assembly corrected for the second time is adopted; the photoelectric load is mounted on the rotating component, the device is mounted on the unmanned helicopter platform for flight test, the stiffness of the elastic assembly is corrected for the third time according to the actual flight imaging quality of the photoelectric load, and the stiffness is taken as the final stiffness of the elastic assembly.

3. The low frequency isolation transition connection apparatus of claim 2, wherein, The stiffness of the three groups of elastic components is preset, specifically, the stiffness of each elastic element in the middle elastic component is preset as E 1. The stiffness of each elastic element in the upper and lower elastic components is preset as E 2; E 1 = k1 · Mg· l 1· l 2 / L1 / L2 / L2 E 2 = k2- Mg- L1- L2 / 1 l 1 / l 2 / l 2 In the formula, M is the load mass, g is the gravity acceleration, L1 and L2 are the outer arm lengths of the first and second hinges respectively, l 1、 l 2L1 and L2 are the inner arm lengths of the first and second hinges respectively; k1 and k2 are the correlation coefficients, k1 = f1 (α, β, n, Mg, L1, l 1), k2 = f2 (α, β, n, Mg, L2, l 2); f1 and f2 represent dimensionless functions, α is the included angle formed by the first hinge and the center plane, β is the included angle formed by the second hinge and the center plane, and n is the number of elastic elements in a set of elastic assemblies; each elastic element in the same elastic assembly is located in the same horizontal plane, and the center plane refers to the plane in which the middle elastic assembly is located.

4. The low frequency isolation transition connection apparatus of claim 1, wherein, The upper side of the first hinge is provided with a first shaft pin and a second shaft pin, which are connected to the first support and the elastic assembly at the upper part respectively; the first hinge and the second hinge are connected by a third shaft pin, which is also connected to the elastic assembly at the middle part; the lower side of the second hinge is provided with a fourth shaft pin and a fifth shaft pin, which are connected to the elastic assembly at the lower part and the second support respectively.

5. The low frequency isolation transition connection apparatus of claim 1, wherein, The elastic element adopts a spring, a rubber rod, an air strut or a viscous strut.

6. The low frequency isolation transition connection apparatus of claim 1, wherein, The fixed node adopts a circular ring or a circular sheet.

7. The low frequency isolation transition connection apparatus of claim 1, wherein, The number of hinge assemblies is 2-6.

8. The low frequency isolation transition connection apparatus of claim 1, wherein, The support assembly and the hinge assembly adopt aluminum alloy, titanium alloy, carbon fiber composite material or PEEK engineering plastic.

9. A low frequency isolation transition connection device as claimed in any of claims 1-8, characterized in that The rotating component comprises a rotating shaft assembly and a motor assembly, the rotating shaft assembly comprises a first rotating shaft, a second rotating shaft and a third rotating shaft connected in sequence, the upper end of the first rotating shaft is connected to the second support by the motor assembly, and the two ends of the second rotating shaft are connected to the lower end of the first rotating shaft and the third rotating shaft by the motor assembly respectively; the first rotating shaft, the second rotating shaft and the third rotating shaft are used to realize vertical rotation, horizontal rotation and longitudinal rotation respectively.

10. The low frequency isolation transition connection apparatus of claim 9, wherein, The rotating shaft assembly adopts aluminum alloy, carbon fiber composite material or PEEK engineering plastic.

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