Buffering device for adapting to deformation of carrier for inertial navigation system

Abstract

This invention relates to a buffer device for an inertial navigation system that adapts to the deformation of the carrier, comprising upper and lower mounting plates and three sets of buffer rods. The lower ends of each of the three sets of buffer rods are connected to the lower mounting plate using a Hooke pair; the upper ends of two sets of buffer rods are connected to the upper mounting plate using a ball joint; and the upper end of the third buffer rod assembly is connected to the upper mounting plate using a fixed joint. The upper mounting plate is made of the same material as the mounting base of the resonant inertial navigation system; the lower mounting plate is made of the same material as the carrier mounting surface. The centers of the three Hooke pair bases connected to the lower mounting plate are located at the three vertices of an equilateral triangle, and the three Hooke pair bases are installed in the same direction. The centers of the two ball joint bases connected to the upper mounting plate and the center of the fixed mounting base are located at the three vertices of an equilateral triangle, respectively. The diameter of the circle formed by the center points of the ball joint bases and the fixed mounting base on the upper mounting plate is equal to the diameter of the circle formed by the center points of the three Hooke pair bases on the lower mounting plate. This invention can eliminate stress effects and provide a buffering effect.

Description

Technical Field

[0001] This invention belongs to the field of resonant inertial navigation systems, and specifically relates to a buffer device for inertial navigation systems that adapts to the deformation of the carrier. Background Technology

[0002] A novel inertial navigation system is constructed using a resonant gyroscope as the core sensing element, combined with an accelerometer assembly. Resonant inertial navigation systems typically employ strapdown mounting, meaning the system is rigidly connected to the carrier. To ensure a stable internal temperature field, the mounting plate is generally made of a material with low thermal conductivity, thereby reducing the impact of carrier temperature variations on the system's navigation accuracy. The mounting plate may even be made of high-strength non-metallic materials.

[0003] However, the difference in materials between the mounting base and the carrier leads to new problems: when the ambient temperature changes, the difference in the thermal expansion coefficients of the materials results in different thermal deformations between the carrier and the resonant inertial navigation system, subjecting the resonant inertial navigation system to significant thermal stress. Under this thermal stress, the internal structural components of the resonant inertial navigation system deform, thus reducing its navigation accuracy. Furthermore, when the carrier is subjected to a large impact, the core components of the resonant inertial navigation system are easily damaged. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a buffer device for inertial navigation systems that adapts to the deformation of the carrier, which can eliminate the adverse effects on the navigation accuracy of the resonant inertial navigation system caused by impact, thermal deformation, processing and assembly errors and deformation of the carrier under stress.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution:

[0006] A buffer device for an inertial navigation system that adapts to the deformation of a carrier, characterized in that: the buffer device consists of an upper mounting plate, a lower mounting plate, and three sets of buffer rods; the lower ends of the three sets of buffer rods are respectively connected to the lower mounting plate by a set of Hooke pairs, the upper ends of two sets of buffer rods are respectively connected to the upper mounting plate by two ball joints, and the upper end of another buffer rod assembly is connected to the upper mounting plate by a fixed joint;

[0007] The upper end of the upper mounting plate forms a resonant inertial navigation system mounting platform, and the material of the upper mounting plate is the same as that of the resonant inertial navigation system mounting base plate; the lower end of the lower mounting plate forms a carrier mating surface, and the material of the lower mounting plate is the same as that of the carrier mounting surface.

[0008] The centers of the three Hooke pairs connected to the lower mounting plate are located at the three vertices of an equilateral triangle; and the three Hooke pairs are installed in the same direction. The centers of the ball heads of the two ball joints connected to the upper mounting plate and the centers of the fixed mounting bases of the fixed joints are located at the three vertices of an equilateral triangle; the diameter of the circle formed by the center point of the ball head and the center point of the fixed mounting base on the upper mounting plate is the same as the diameter of the circle formed by the center points of the three Hooke pairs on the lower mounting plate.

[0009] Furthermore, each set of Hooke pairs consists of a Hooke pair base, a Hooke pair rotating seat, and two pins. The Hooke pair base is fixed to the lower mounting plate by screws and connected to the Hooke pair rotating seat through the first pin, allowing the Hooke pair rotating seat to rotate around the first pin, thus forming a rotating pair. The Hooke pair rotating seat has a through hole, which engages with the second pin to form a second rotating pair, and the center lines of the two pins remain perpendicular.

[0010] Furthermore, each buffer rod assembly consists of an outer sleeve, an upper support rod, a lower support rod, a slider, a shift fork, an upper spring, and a lower spring. The lower end of the upper support rod and the upper end of the lower support rod are coaxially and fixedly connected to form a rod assembly. The slider is fitted onto the rod assembly, forming a sliding pair. An upper spring fitted onto the rod assembly is press-fitted between the upper end of the slider and the upper end boss of the upper support rod. A lower compression spring fitted onto the rod assembly is press-fitted between the lower end of the slider and a boss located near the middle of the lower support rod. The rod assembly, slider, and upper and lower springs are inserted into the inner cavity of the outer sleeve from bottom to top with a clearance fit, forming a sliding pair. The shift fork is inserted into a radial shift fork hole provided on the side wall of the outer sleeve, and the inner end of the shift fork forms a pin connection with the slider. The upper end of the outer sleeve is provided with a ball head, which is connected to the main body of the outer sleeve through a ball neck. The lower part of the lower support rod is located outside the lower end of the outer sleeve and is provided with a pin hole that mates with the second pin shaft.

[0011] Furthermore, the main body of the outer sleeve adopts an outer circle and inner square structure; the upper end boss of the upper support rod and the boss on the lower support rod are both square bosses that match the square inner hole of the main body of the outer sleeve.

[0012] Furthermore, the distance between the two square bosses is 200mm.

[0013] Furthermore, the ball joint is formed by the ball head located at the upper end of the upper support rod and the ball head seat fixed at the lower end of the upper mounting plate, and the ball head seat is formed by the splicing of two hemispherical ball heads.

[0014] The advantages and positive effects of this invention are as follows:

[0015] This invention designs a buffer device for inertial navigation systems that adapts to carrier deformation. By constructing a 3U-2S parallel mechanism, the mechanism achieves zero degrees of freedom, solving the over-constraint problem in conventional fixed constraints, realizing kinematic parameter decoupling, and eliminating the influence of thermal stress, assembly stress, and local deformation of the carrier caused by mismatched thermal expansion coefficients on the resonant inertial navigation system, thus improving navigation accuracy. By designing the preload of the spring inside the buffer rod, the buffer device can be guaranteed to have high support stiffness. The energy absorbed by the spring deformation is used to mitigate the energy brought by external impacts, thus achieving a buffering effect. Attached Figure Description

[0016] Figure 1 This is a reference diagram showing the usage state of the present invention;

[0017] Figure 2 This is a schematic diagram of the overall structure of the present invention;

[0018] Figure 3 This is a schematic diagram of the Hooke sub-base of the present invention being fixed on the lower mounting plate;

[0019] Figure 4 This is a schematic diagram of the Hooke sub-model of the present invention;

[0020] Figure 5 This is a longitudinal sectional view of the buffer rod of the present invention;

[0021] Figure 6 This is a schematic diagram of the upper and lower support assembly of the present invention;

[0022] Figure 7 This is a schematic diagram of the outer sleeve of the present invention;

[0023] Figure 8 This is a schematic diagram of the spherical pair of the present invention;

[0024] Figure 9 This is a schematic diagram of the hemispherical headstock structure of the present invention;

[0025] Figure 10 This is a schematic diagram of the upper mounting plate and connectors. Detailed Implementation

[0026] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0027] This invention proposes a buffer device for inertial navigation systems that adapts to the deformation of the carrier. The design concept of this device is to achieve the decoupling of the kinematic parameters of the buffer device through the mutual cooperation between kinematic pairs, thereby eliminating the adverse effects on the navigation accuracy of the resonant inertial navigation system caused by impact, thermal deformation, processing and assembly errors and the deformation of the carrier under stress.

[0028] A buffer device for an inertial navigation system that adapts to carrier deformation is provided. To isolate the effects of impact, thermal deformation, assembly errors, and carrier stress deformation on the resonant inertial navigation system, the present invention adopts the following design scheme:

[0029] 1) 3U-2S parallel mechanism

[0030] like Figure 2 As shown, the buffer device adopts a triangular support structure, consisting of an upper mounting plate 1, a lower mounting plate 2, and three sets of buffer rods 3. The three sets of buffer rods are connected to the lower mounting plate by a Hooke joint 5, and to the upper mounting plate by two ball joints 7 and one fixed joint 6, forming a 3U-2S parallel mechanism.

[0031] The number of degrees of freedom (DOF) of the 3U-2S parallel mechanism is calculated using the Kutzbach-Grvbler formula:

[0032]

[0033] Since one buffer rod is connected to the upper mounting plate by a fixed pair, it can be defined as one component. Therefore, in the formula, n = 4 is the total number of components in the 3U-2S parallel mechanism, and g = 5 is the number of kinematic pairs. The sum of the degrees of freedom of all kinematic pairs is calculated to be 2*3 + 3*2 = 12. This calculation shows that the DOF of the 3U-2S parallel mechanism is 0. The 0 degrees of freedom of the 3U-2S parallel mechanism solves the over-constraint problem in conventional fixed installation methods, achieving kinematic parameter decoupling. Using this parallel mechanism in the buffer device can eliminate the adverse effects of thermal deformation, assembly stress, and carrier deformation on the navigation accuracy of the resonant inertial navigation system.

[0034] 2) The material of the lower mounting plate is consistent with the material of the carrier mounting surface, and the material of the upper mounting plate is consistent with the material of the mounting base plate 4.1 of the resonant inertial navigation system 4, thereby eliminating the influence of thermal deformation on the resonant inertial navigation system.

[0035] 3) Buffer rod assembly

[0036] like Figure 5-7 As shown, the buffer rod assembly uses a pre-compressed spring as an energy storage element. The spring absorbs energy through deformation under force to reduce external impact, thereby protecting the resonant inertial navigation system from damage.

[0037] 4) Dual working modes

[0038] By adjusting the preload of the springs, the static support stiffness of the buffer device is designed, thereby determining the threshold at which the buffer device functions in response to external impacts. When the external impact is less than the threshold, the buffer rod, under the preload of the springs, can be treated as a rigid body. In this case, the buffer device satisfies the 3U-2S parallel mechanism configuration and has high support stiffness, which can eliminate the influence of thermal deformation, machining and assembly errors, and the deformation of the carrier under stress on the resonant inertial navigation system. When the external impact is greater than the threshold, the buffer rod assembly comes into play. Under the action of inertial force, the springs deform, absorb energy, and reduce the impact, achieving the purpose of buffering. After the external impact has passed, the buffer device will automatically return to its initial attitude state under the action of the upper and lower springs.

[0039] The specific structure is as follows:

[0040] 1) Lower mounting plate

[0041] like Figure 3 As shown in the attached figure, the lower mounting plate is preferably, but not limited to, a circular mounting plate. The lower mounting plate contacts the mounting surface of the carrier and is fixedly connected by screws. The material of the lower mounting plate is the same as that of the mounting surface of the carrier, which can eliminate the influence of thermal stress caused by the difference in the coefficient of thermal expansion. Three Hooke sub-bases are mounted on the lower mounting plate, and the centers of the three Hooke sub-bases are respectively located at the three vertices of an equilateral triangle; the three Hooke sub-bases are installed in the same direction, thereby ensuring that one axis of the Hooke sub-base can rotate around the X-axis.

[0042] 2) Hooke's Subsidiary

[0043] like Figure 4 As shown, the Hooke pair consists of a Hooke pair base 5.1, a Hooke pair rotating seat 5.3, and a pin. The Hooke pair base is fixed to the lower mounting plate with screws. The Hooke pair rotating seat is mounted on the Hooke pair base via the first pin 5.2, allowing the Hooke pair rotating seat to rotate around the first pin, forming a rotating pair (this rotating pair can rotate around the X-axis). Furthermore, the Hooke pair rotating seat has a through-hole 5.4 for engaging with the second pin 3.8 to form a second rotating pair, and the center lines of the two rotating pins remain perpendicular.

[0044] 3) Buffer rod assembly

[0045] like Figure 5-7As shown, the buffer rod assembly consists of an outer sleeve 3.7, a fork 3.6, a lower support rod 3.1, an upper support rod 3.5, a slider 3.3, an upper spring 3.2, and a lower spring 3.4. The outer sleeve, the upper support rod, and the lower support rod form a sliding pair with a clearance fit. The slider and the optical axis rod assembly formed by splicing the upper and lower support rods also form a sliding pair. When the buffer device is subjected to an external force exceeding the design threshold, relative movement will occur between the outer sleeve and the upper and lower support rods. This will cause the fork inside the radial fork hole 3.7.1 on the outer sleeve to move the slider, thereby compressing the upper spring (or lower spring) to achieve the purpose of energy absorption and buffering.

[0046] The upper and lower support rods can be connected together by threads to ensure the feasibility of the assembly process. In addition, the upper spring support platform 3.1.1 and the lower spring support platform 3.5.1 together cooperate with the outer sleeve to form a sliding pair. The distance between the two support platforms is 200mm, which has a large span, improves the working accuracy of the sliding pair, and reduces the swing amplitude of the outer sleeve.

[0047] The main body of the outer sleeve adopts an outer circular and inner square structure, meaning the outer surface is cylindrical and the inner surface has a square hole (3.7.2). The outer circle ensures ease of machining, while the inner square structure ensures that the fit between the outer sleeve and the upper and lower support rods forms a sliding pair, with only one degree of translational freedom in one direction. If an outer circular and inner circular structure were used, the fit between the outer sleeve and the upper and lower support rods would form a cylindrical pair, and the outer sleeve would have one degree of rotational freedom along its own axis. A ball head is designed at the top of the outer sleeve, which mates with a ball head seat to form a ball joint.

[0048] 4) Ball support

[0049] like Figure 8-9 As shown, each ball joint consists of a ball head 7.1 at the end of the outer sleeve and a ball head seat 7.2. Each ball head seat is composed of two hemispherical ball head seats. The design of two hemispherical ball head seats ensures the feasibility of ball joint assembly.

[0050] 5) Upper mounting plate

[0051] like Figure 10 As shown, the material of the upper mounting plate is consistent with that of the mounting base plate of the resonant inertial navigation system, which can eliminate the influence of thermal stress caused by the difference in thermal expansion coefficients; two complete ball joints and one fixed base are installed on the back of the upper mounting plate, and the centers of the two ball joints and the center of the fixed base are respectively located at the three vertices of an equilateral triangle; in addition, the circle formed by the center point of the ball joint and the center point of the fixed base on the upper mounting plate is equal in diameter to the circle formed by the center points of the three Hooke sub-bases on the lower mounting plate.

[0052] This buffer device is not limited to the installation of resonant inertial navigation systems; it can be used in the installation of any precision instrument sensitive to thermal and assembly stresses. Furthermore, when impact conditions are not a concern, the buffer rod can be replaced with a metal rod, reducing the complexity of the entire device while still eliminating the effects of thermal and assembly stresses on the instrument.

[0053] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A buffer device for an inertial navigation system that adapts to the deformation of a carrier, characterized in that: The buffer device consists of an upper mounting plate, a lower mounting plate, and three sets of buffer rods. The lower ends of the three sets of buffer rods are connected to the lower mounting plate by a set of Hooke pairs, the upper ends of the two sets of buffer rods are connected to the upper mounting plate by two ball joints, and the upper end of the other buffer rod assembly is connected to the upper mounting plate by a fixed joint. The upper end of the upper mounting plate forms a resonant inertial navigation system mounting platform, and the material of the upper mounting plate is the same as that of the resonant inertial navigation system mounting base plate; the lower end of the lower mounting plate forms a carrier mating surface, and the material of the lower mounting plate is the same as that of the carrier mounting surface. The centers of the three Hooke pairs connected to the lower mounting plate are located at the three vertices of an equilateral triangle; and the three Hooke pairs are installed in the same direction. The centers of the ball heads of the two ball joints connected to the upper mounting plate and the centers of the fixed mounting bases of the fixed joints are located at the three vertices of an equilateral triangle; the diameter of the circle formed by the center point of the ball head and the center point of the fixed mounting base on the upper mounting plate is the same as the diameter of the circle formed by the center points of the three Hooke pairs on the lower mounting plate.

2. The buffer device for adapting to carrier deformation in an inertial navigation system according to claim 1, characterized in that: Each set of Hooke pairs consists of a Hooke pair base, a Hooke pair rotating seat, and two pins. The Hooke pair base is fixed to the lower mounting plate with screws and connected to the Hooke pair rotating seat through the first pin, so that the Hooke pair rotating seat can rotate around the first pin, forming a rotating pair. The Hooke pair rotating seat has a through hole, which cooperates with the second pin to form a second rotating pair, and the center lines of the two pins remain perpendicular.

3. The buffer device for adapting to carrier deformation in an inertial navigation system according to claim 1, characterized in that: Each buffer rod assembly consists of an outer sleeve, an upper support rod, a lower support rod, a slider, a shift fork, an upper spring, and a lower spring. The lower end of the upper support rod and the upper end of the lower support rod are coaxially and fixedly connected to form a rod assembly. The slider is fitted onto the rod assembly to form a sliding pair. An upper spring fitted onto the rod assembly is press-fitted between the upper end of the slider and the upper end boss of the upper support rod. A lower compression spring fitted onto the rod assembly is press-fitted between the lower end of the slider and a boss located near the middle of the lower support rod. The rod assembly, slider, and upper and lower springs are inserted into the inner cavity of the outer sleeve from bottom to top with a clearance fit, forming a sliding pair. The shift fork is inserted into a radial shift fork hole on the side wall of the outer sleeve, and the inner end of the shift fork is pinned to the slider. The upper end of the outer sleeve is provided with a ball head, which is connected to the main body of the outer sleeve through a ball neck. The lower part of the lower support rod is located outside the lower end of the outer sleeve and is provided with a pin hole that mates with the second pin.

4. The buffer device for adapting to carrier deformation in an inertial navigation system according to claim 3, characterized in that: The main body of the outer sleeve adopts an outer circle and inner square structure; the upper end boss of the upper support rod and the boss on the lower support rod are both square bosses that match the square inner hole of the main body of the outer sleeve.

5. The buffer device for adapting to carrier deformation in an inertial navigation system according to claim 4, characterized in that, The distance between the two square bosses is 200mm.

6. The buffer device for adapting to carrier deformation in an inertial navigation system according to claim 3, characterized in that, The ball joint is formed by the ball head located at the upper end of the upper support rod and the ball head seat fixed at the lower end of the upper mounting plate. The ball head seat is formed by the splicing of two hemispherical ball heads.

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