CN111811504A

CN111811504A - Laminated micro-inertia measuring unit under large-overload high-dynamic application environment

Info

Publication number: CN111811504A
Application number: CN202010809926.0A
Authority: CN
Inventors: 鞠莉娜; 蒋鹏; 黄艳辉
Original assignee: China North Industries Group Corp No 214 Research Institute Suzhou R&D Center
Current assignee: China North Industries Group Corp No 214 Research Institute Suzhou R&D Center
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2020-10-23

Abstract

The invention discloses a laminated micro-inertia measurement unit under a large-overload high-dynamic application environment, which comprises at least two circuit boards, wherein at least one type of inertia sensor is arranged on each circuit board, the circuit boards are fixed in a laminated mode through an elastic support structure, the elastic support structure comprises a fixing part and an elastic part, the elastic part is made of elastic materials, the circuit boards are electrically interconnected through a flexible conduction band connector, the flexible conduction band connector comprises a flexible conduction band, and the length of the flexible conduction band is larger than the distance between the circuit boards. The micro-inertia measurement unit is designed in a laminated mode, all the inertia sensors are installed in a plane, the large overload resistance of the system is improved, electronic components in the system are assembled in a laminated mode through specially designed elastomer supporting materials, and mechanical protection of the micro-inertia measurement unit in a large overload high-dynamic environment is achieved.

Description

Laminated micro-inertia measuring unit under large-overload high-dynamic application environment

Technical Field

The invention relates to the technical field of structure and mechanical protection design of a micro-inertia measurement unit, in particular to a laminated micro-inertia measurement unit under a large-overload high-dynamic application environment.

Background

With the development of semiconductor technology, MEMS (micro electro mechanical system) technology is widely used in the military fields such as unmanned aerial vehicles, guided munitions, and stabilized platforms due to its miniaturization, low cost, and high reliability. The micro-inertia measurement unit based on the MEMS technology is used as a sensor system for measuring dynamic data of a carrier, has the advantages of high precision, small volume, strong environmental adaptability, low cost and the like, and can be applied to severe environments such as large overload, high dynamic state and the like. The micro-inertia measurement unit senses motion through an MEMS (micro-electromechanical systems) inertial sensor integrated inside, and the measurement principle is as follows: the movement and relative displacement of the silicon micro-mechanical structure in the sensor generate detectable electric signals, and the special integrated circuit processes the electric signals and outputs analog or digital quantity to the outside, thereby sensing the movement information of the carrier.

The micro-inertia measurement unit is used as a detection device for the motion state of a carrier, the requirement of six-degree-of-freedom inertial parameter measurement needs to be met, and the six-degree-of-freedom measurement of the sensitive axial direction of the micro-inertia measurement unit is usually realized by adopting the orthogonal assembly of an inertial sensor. Due to the design principle of a silicon micro-mechanical structure of the MEMS inertial sensor, the overload impact bearing capacity is weak under the condition of lateral vertical installation. And under the environment of large overload and high dynamic, the micro-inertia measurement unit can bear great transmission stress and high-frequency vibration, and both can influence or even fail the system function. Therefore, for the reliability under the severe application environment, the system scheme of the micro-inertia measurement unit needs to be optimized and the environment protection design needs to be carried out. And in order to reduce errors of machining, assembly and the like and ensure the reliability and the matching strength of the system, the micro-inertia measurement unit avoids the splicing assembly design of multiple parts as much as possible. Some existing methods and defects are as follows:

the invention patent of publication No. CN 110017835A, inertia measurement unit and mobile device using the same, proposes an inertia measurement unit with constant temperature heating function and a mobile device using the same. The inside frame construction that adopts the high thermal conductivity of this inertia measurement unit utilizes the heating source to produce the heat and heats frame embedded circuit board, through the real-time temperature of multisensor perception system, and inside heat insulating board keeps the system with the gum cover and predetermines the temperature. This scheme is through special structure and heat conduction path design, guarantees that the system is in the constant temperature state at the during operation, reduces the temperature drift of system, promotes system performance. The design mainly aims at the temperature characteristic of the inertia measurement unit to carry out system environment optimization design, and special protection is not carried out on a large overload and high dynamic application environment.

The invention patent 'modularized and expandable MEMS inertial measurement unit' of publication number CN 105352501A provides an expandable MEMS inertial measurement unit with a sensitive module orthogonally assembled with a cube frame and a computer module laminated inside. According to the scheme, four sensitive modules are vertically assembled with four side frames of a square support through screws, the two sensitive modules and a computer module are horizontally assembled inside the square support, and the two sensitive modules and the computer module are connected and supported through a single-head stud. The inertia measurement unit is compact in interior, high in modularization and flexibility degree and good in system configurability. However, the three modules are stacked inside the cube support, the internal space is very limited, and the sensitive modules are vertically and horizontally mounted, so that the signal connection between the sensitive modules and the computer module can improve the assembly complexity of the inertia measurement unit.

The invention patent of publication No. CN 104296746A, a novel micro inertial measurement unit, proposes a micro inertial measurement unit combination which can weld and assemble a MEMS accelerometer, a MEMS gyroscope and a mounting base in the same plane or in parallel. The invention selects MEMS accelerometers and MEMS gyroscopes with different sensitive structures, so that the inertial measurement axial direction of the MEMS accelerometers and the inertial measurement axial direction of the MEMS gyroscopes is horizontal or vertical to the welding plane of the sensor, thereby meeting the requirement of measuring inertial parameters with six degrees of freedom. The scheme avoids orthogonal assembly of the inertial sensor, and has the advantages of high space utilization rate, high system integration level and strong overload resistance. But it does not provide special protection against large overload, highly dynamic application environments.

The invention patent of publication No. CN 107966144 a, "an assembly structure based on an inertial measurement combination of a MEMS sensor", proposes an assembly structure scheme for implementing three-axis orthogonal mounting of a MEMS inertial sensor through a mounting base. The structure of the mounting base is similar to a hexahedron, the MEMS sensors are mounted on the top surface and the side surfaces, and the gyro signal processing circuit is mounted on the bottom surface. A wiring groove is reserved in the mounting base, and the signal wires are bound to form a wiring harness and led out outwards. According to the scheme, the signal conversion circuit is arranged in the closed cavity at the bottom of the base, so that physical isolation is realized, and signal interference is reduced. However, the assembly body is complex in structure and high in processing difficulty, and the internal signal transmission adopts a wire mode, so that the assembly flow is increased.

The invention patent of CN 105922836A discloses a micro inertial measurement unit composed of an outer shell, an inertial assembly, a vibration absorber and a sealing gasket. Wherein the outer shell and the sealing pad form a closed space, the inertia assembly body is suspended in the closed shell through the shock absorber, and the inner air property high damping elastomer is arranged in the inertia assembly body. The inner surface of the lower shell is provided with a protruding stop structure, so that the shock resistance of the system can be adjusted. The vibration reduction rubber of the vibration reducer is provided with uniform grooves on the upper surface and the lower surface, and the resonance frequency of the vibration reducer can be controlled. The scheme has the advantages that the impact resistance and the vibration reduction performance can be adjusted according to the application environment, the flexibility is higher, and various damping designs are favorable for vibration isolation. However, a certain angle exists between the sensitive axial direction of the inertia device and the axial direction of the miniature inertia measurement unit, and the scale needs to be adjusted through system compensation, so that the system error is increased.

Disclosure of Invention

In view of the above technical problems, the present invention aims to: the laminated micro-inertia measurement unit is designed in a laminated mode, all inertia sensors are installed on a plane, the large overload resistance of the system is improved, electronic components in the system are assembled in a laminated mode through specially designed elastomer supporting materials, and mechanical protection of the micro-inertia measurement unit in the large overload high-dynamic environment is achieved.

The technical scheme of the invention is as follows:

the utility model provides a stacked little inertial measurement unit under high dynamic application environment of big overload, includes two piece at least circuit boards, be provided with at least one kind inertial sensor on the circuit board, it is fixed through the elasticity support structure stromatolite between the circuit board, elasticity support structure includes fixed part and elasticity portion, the elasticity portion is made by elastic material, carry out the electrical interconnection through flexible conduction band connector between the circuit board, flexible conduction band connector includes flexible conduction band, the length of flexible conduction band is greater than the interval between the circuit board.

In an optimal technical scheme, material parameters of the elastic material are designed according to an application environment, and deformation of the elastic part is ensured to be in an elastic interval in a large overload bearing stage.

In the preferred technical scheme, the damping characteristic of the elastic material and the natural frequency of the system are calculated, so that the damping characteristic of the elastic material is inconsistent with the natural frequency of the system.

In the preferred technical scheme, the fixed part is connected with the elastic part through an embedded structure and is fixedly connected through viscose.

In an optimized technical scheme, the elastic supporting structure is a circular truncated cone structure, and the fixing part is provided with threads.

In an optimized technical scheme, the flexible conduction band connector further comprises a golden finger pad structure and a plastic body structure, wherein internal routing copper foils are led out from two ends of the flexible conduction band, the golden finger pads with certain strength are formed through thickening, and the golden finger pads and part of the flexible conduction band are subjected to injection molding to obtain the plastic body structure.

In a preferred embodiment, the control circuit board is connected to the electrical connector by a flexible strip connector.

In a preferred technical scheme, a metal shell is arranged on the periphery of the stacked micro-inertia measurement unit and comprises a square sleeve and a plane base, and mounting flanges are arranged on each side of the square sleeve and each side of the plane base.

Compared with the prior art, the invention has the advantages that:

1. electronic components in the system are all laminated and assembled by adopting specially designed elastomer supporting materials, so that the mechanical protection of the micro-inertia measurement unit in a large-overload high-dynamic environment is realized, and the circuit boards are interconnected by virtue of flexible conduction bands, so that the reliability of an electrical interface is ensured. Meanwhile, the laminated structure and the information interconnection mode enable the function of the micro-inertia measurement unit to have flexibility and expansibility.

2. The micro-inertia measurement unit adopts a laminated design and carries out plane installation on all the inertia sensors, so that the movement direction of the silicon micro-sensitive structure of the inertia sensor is not coincident with the overload direction when the micro-inertia measurement unit bears a large overload state, and the large overload resistance of the system is improved. The circuit board supporting structure is made of elastomer materials with certain strength, so that large overload impact and high-frequency vibration are relieved through deformation, and the transmission of overload and vibration can be attenuated by adopting the same mode for mechanical connection between the circuit boards. The material characteristics of the elastic supporting structure are designed, so that the material is in an elastic deformation interval in the process of bearing large overload, and the sensor circuit board of the micro-inertia measuring unit can return to the initial position after the large overload impact stage is finished. Because the supporting structure is made of elastic materials, the external vibration is transmitted to the interior of the micro-inertia measuring unit structure, and the circuit board can compress or stretch the elastic supporting structure due to the inertia of the circuit board, so that the displacement caused by the vibration is reduced, and the vibration attenuation effect is achieved. The distance between the circuit boards is changed to a certain extent under the condition, and the circuit boards adopt the electrical interconnection mode of the traditional wiring harness, so that the wiring harness moves and impacts between the circuit boards, great noise is generated on output signals, and the system function is influenced; by adopting the mode of interconnecting the connectors, the vibration can influence the insertion strength and reliability between the circuit boards. The invention adopts the electrical interconnection mode of the flexible conduction band, and the length of the conduction band is slightly longer than the distance between the circuit boards, so that the electrical interconnection is kept firm and reliable in the state that the distance between the circuit boards is compressed or stretched.

Drawings

The invention is further described with reference to the following figures and examples:

FIG. 1 is a schematic view of a micro inertial measurement unit of the present invention;

FIG. 2 is a schematic diagram of a micro inertial measurement unit system of the present invention;

FIG. 3 is a schematic view of a stacked design of a micro inertial measurement unit according to the present invention;

FIG. 4 is a schematic view of an embodiment of a flexible support structure;

FIG. 5 is a schematic view of the connection structure of FIG. 4;

FIG. 6 is a schematic view of an alternative embodiment of a flexible support structure;

FIG. 7 is a schematic view of the connection structure of FIG. 6;

fig. 8 is a schematic view of the overall structure of the flexible belt connector of the present invention;

fig. 9 is a schematic view of the flexible strap connector of the present invention with the injection molded-out.

1: square sleeve, 2: plane base, 3: circuit board locking member, 41: upper elastic support structure, 411: upper-end metal external thread structure, 412: elastic damping material structure, 413: lower end metal external thread structure, 42: middle elastic support structure, 421: upper end metal internal thread structure, 422: elastic damping material structure, 423: lower end metal external thread structure, 43: lower elastic support structure, 431: upper end metal internal thread structure, 432: elastic damping material structure, 433: lower extreme metal external screw thread structure, 5: accelerometer circuit board, 51: x-axis accelerometer, 52: y-axis accelerometer, 53: z-axis accelerometer, 6: gyroscope circuit board, 61: x-axis gyroscope, 62: y-axis gyroscope, 63: z-axis gyroscope, 7: control circuit board, 71: control chip, 8: flexible harness connector, 801: gold finger pad, 802: plastic structure, 803: flexible conduction band, 9: electrical structure connector, 10: groove, 11: through hole, 12: bump, 13: an extension portion.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

As shown in figure 1, in the laminated micro-inertia measurement unit designed by the invention, an external metal shell is made of high-strength superhard aluminum and is matched in the form of a square sleeve 1 and a plane base 2. Mounting flanges are arranged on each side of the square sleeve 1 and each side of the plane base 2, and threaded holes and round through holes are respectively formed according to the mounting structure, so that system assembly of the micro-inertia measurement unit and positioning and mounting on a carrier mounting plane are realized.

The stacked micro-inertia measurement unit under the large overload high-dynamic application environment comprises at least two circuit boards, at least one type of inertia sensor is arranged on each circuit board, the circuit boards are fixed in a stacked mode through an elastic support structure, the elastic support structure comprises a fixing portion and an elastic portion, the elastic portion is made of elastic materials, electrical interconnection is conducted between the circuit boards through a flexible conduction band connector, the flexible conduction band connector comprises a flexible conduction band, and the length of the flexible conduction band is larger than the distance between the circuit boards.

As shown in fig. 2 and 3, the present embodiment is described by taking three circuit boards as an example, including a control circuit board 7, an accelerometer circuit board 5 and a gyroscope circuit board 6. The control circuit board 7 is provided with a control chip 71, the accelerometer circuit board 5 is provided with an X-axis accelerometer 51, a Y-axis accelerometer 52 and a Z-axis accelerometer 53, and the gyroscope circuit board 6 is provided with an X-axis gyroscope 61, a Y-axis gyroscope 62 and a Z-axis gyroscope 63.

A lower elastic supporting structure 43 is fixed inside the planar base 2 through a threaded hole, the lower elastic supporting structure 43 comprises an upper metal internal thread structure 431, an elastic damping material structure 432 and a lower metal external thread structure 433, the lower elastic supporting structure 43 is approximately a two-layer circular truncated cone structure, as shown in fig. 6 and 7, the lower circular truncated cone is made of metal material and is provided with an external thread, and is in locking fit with the planar base 2; the upper round platform comprises elastic materials, the top surface of the upper round platform is provided with metal structure internal threads, and the upper round platform is matched with the middle elastic supporting structure 42 to fix the control circuit board 7. Upper end metal internal thread structure 431 and lower extreme metal external thread structure 433 are connected with elastic damping material structure 432 through inserted structure, as shown in fig. 7, link firmly through the viscose, and inserted structural design increases the face of bonding, makes the assembly firm, improves the reliability.

Middle part elastic support structure 42 is the same with lower part elastic support structure 43, as shown in fig. 6, 7, including upper end metal internal thread structure 421, elastic damping material structure 422, lower extreme metal external thread structure 423, middle part elastic support structure 42 cooperates with upper portion elastic support structure 41, fixed gyroscope circuit board 6, upper portion elastic support structure 41 includes upper end metal external thread structure 411, elastic damping material structure 412, lower extreme metal external thread structure 413, as shown in fig. 4, 5, accelerometer circuit board 5 is fixed with circuit board retaining member 3 to upper portion elastic support structure 41. The upper end metal external thread structure 411 and the lower end metal external thread structure 413 are connected with the elastic damping material structure 412 through an embedded structure and then are fixedly connected through glue.

In a preferred embodiment of the damascene structure, as shown in fig. 5, the elastic damping material structure 412 is a circular truncated cone structure, two ends of the elastic damping material structure are provided with grooves 10, a through hole 11 is formed in the middle of the elastic damping material structure, the middle of the upper end metal external thread structure 411 and the lower end metal external thread structure 413 are provided with bumps 12 matched with the through hole 11, the edge of the elastic damping material structure is provided with an extension 13 extending downwards, and the extension 13 is in snap fit with the grooves 10.

The elastic damping material structure is made of an elastic material, such as a hard silicone rubber or a polyurethane material, and the related material parameters of the hard silicone rubber or the polyurethane material have a wide range and different characteristics of components, so detailed parameters are not listed here. The elastic material is designed according to the application environment of the micro-inertia measurement unit, and the deformation of the support structure is ensured to be in an elastic region in a large overload bearing stage. Meanwhile, the damping characteristic and the natural frequency of the system are considered, high-frequency vibration transmitted from the outside in a working state is attenuated, the resonant frequency of the carrier system is avoided, and the reliability of the micro-inertia measuring unit is improved.

And flexible conducting strip connectors 8 are designed among the circuit boards, so that signal interconnection among the circuit boards is realized. As shown in fig. 8 and 9, the flexible conductive tape connector 8 is of a plastic body structure provided with gold finger pads, and a flexible conductive tape made of Polyimide (PI) or other high-reliability substrate is used in the middle, and the flexible conductive tape connector 8 includes gold finger pads 801, a plastic structure 802, and a flexible conductive tape 803. Internal wiring copper foils are led out from two ends of the flexible conduction band 803, a golden finger pad 801 with certain strength is formed through thickening, the golden finger pad 801 and a part of the flexible conduction band 803 are subjected to injection molding by using a specially designed mold, and a plastic body structure 802 is established, so that the flexible conduction band connector 8 with an electrical interconnection effect is realized. The micro-inertia measurement unit electrical interface is also connected by a flexible conduction band, is led out from the control circuit board 7 and is connected to an electrical structure connector 9 through a flexible conduction band connector 8. The accelerometer circuit board 5 of the micro-inertia measurement unit has the same structure as the gyroscope circuit board 6, the relative positions of the signal interfaces in the circuit board are the same, the communication modes are the same, such as SPI, IIC and the like, and the equipotential connection and the assembly as required between the accelerometer circuit board and the control circuit board 7 are realized. If the system function requirement is a six-axis micro-inertia measurement unit, according to a standard structure: the control circuit, the gyroscope circuit and the accelerometer circuit are assembled in a laminated mode from bottom to top to realize functions; if the system function requirement is three (two) axis accelerometers, removing the gyroscope circuit, and laminating and assembling the gyroscope circuit and the accelerometer circuit from bottom to top according to the control circuit; and if the system function requirement is three (two) axis gyroscopes, removing the accelerometer circuit, and laminating and assembling the control circuit and the gyroscope circuit from bottom to top. If the measurement function needs to be expanded, the circuit board design can be carried out according to the existing signal interface, such as the addition of geomagnetic and inclinometer circuit boards. The control circuit board can be functionally extended, and a navigation module is added, so that the micro-inertia measurement assembly is transformed into a micro-inertia navigation assembly.

Because electronic components in the system are all laminated and assembled by adopting specially designed elastomer supporting materials, the mechanical protection of the micro-inertia measurement unit in a large-overload high-dynamic environment is realized, and the circuit boards are interconnected by flexible conduction bands to ensure the reliability of an electrical interface. Meanwhile, the laminated structure and the information interconnection mode enable the function of the micro-inertia measurement unit to have flexibility and expansibility.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. The stacked micro-inertia measurement unit under the large-overload high-dynamic application environment comprises at least two circuit boards, wherein at least one type of inertia sensor is arranged on each circuit board, the circuit boards are fixed in a stacked mode through an elastic support structure, the elastic support structure comprises a fixing portion and an elastic portion, the elastic portion is made of elastic materials, the circuit boards are electrically interconnected through a flexible conduction band connector, the flexible conduction band connector comprises a flexible conduction band, and the length of the flexible conduction band is larger than the distance between the circuit boards.

2. The stacked micro inertial measurement unit under a high overload and high dynamic application environment according to claim 1, wherein the material parameters of the elastic material are designed according to the application environment to ensure that the deformation of the elastic part is in an elastic range in a large overload stage.

3. The stacked micro inertial measurement unit under a large overload and high dynamic application environment of claim 2, wherein the damping characteristic of the elastic material and the system natural frequency are calculated so that the damping characteristic of the elastic material is inconsistent with the system natural frequency.

4. The stacked micro inertial measurement unit under high-overload and high-dynamic application environment according to claim 1, wherein the fixing portion is connected with the elastic portion through a mosaic structure and fixedly connected through glue.

5. The stacked micro inertial measurement unit in a high overload and dynamic application environment according to claim 1, wherein the elastic support structure is a circular truncated cone structure, and the fixing part is provided with a thread.

6. The stacked micro-inertia measurement unit under a large-overload high-dynamic application environment according to claim 1, wherein the flexible conduction band connector further comprises a golden finger pad structure and a plastic body structure, internal routing copper foils are led out from two ends of the flexible conduction band, a golden finger pad with a certain strength is formed through thickening, and the golden finger pad and a part of the flexible conduction band are subjected to injection molding to obtain the plastic body structure.

7. The stacked micro inertial measurement unit in a high overload and high dynamic application environment of claim 1, wherein the control circuit board is connected to the electrical structure connector through a flexible conductive strip connector.

8. The stacked micro inertial measurement unit under a high-overload and high-dynamic application environment according to claim 1, wherein a metal shell is arranged on the periphery of the stacked micro inertial measurement unit, and the metal shell comprises a square sleeve and a planar base, and a mounting flange is arranged on each side of the square sleeve and the planar base.