Sensor block assembly with isolator rigidly connected to sensor block

Abstract

The sensor block assembly includes a sensor block and an isolator rigidly connected to the sensor block by adhesive, epoxy, and / or welding. A method of assembling a sensor block assembly includes applying an adhesive or epoxy resin to a sensor block and / or an isolator; and compressing the sensor block and / or the isolator together with an adhesive and / or epoxy resin between the sensor block and the isolator, wherein the adhesive and / or epoxy resin forms a rigid mechanical connection between the sensor block and the isolator. A method of assembling a sensor block assembly includes positioning a sensor block proximate an isolator; and welding the sensor block to the isolator to form a rigid mechanical connection between the sensor block and the isolator.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 597,643, filed on November 9, 2023, entitled “NATURAL FREQUENCY SUPPRESSION VIA BONDING / WELDING FOR IMPROVEDSENSOR PERFORMANCE,” which is hereby incorporated by reference in its entirety. Background Art

[0003] Micro-electro-mechanical systems (MEMS) can be used to make sensors and other devices. Summary of the invention

[0004] A sensor block assembly includes at least one sensor block and at least one isolator, the isolator being rigidly connected to the at least one sensor block by at least one of an adhesive, an epoxy, or welding. A method of assembling a sensor block assembly includes: applying at least one of an adhesive or an epoxy to at least one of the at least one sensor block or at least one of the at least one isolator; and compressing at least one sensor block and at least one isolator together with at least one of the adhesive or the epoxy between the at least one sensor block and the at least one isolator, wherein the at least one of the adhesive or the epoxy forms at least one rigid mechanical connection between the at least one sensor block and the at least one isolator. A method of assembling a sensor block assembly includes: positioning at least one sensor block proximate to at least one isolator; and welding the at least one sensor block to the at least one isolator to form at least one rigid mechanical connection between the at least one sensor block and the at least one isolator. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered limiting of the scope of the invention, the exemplary embodiments will be described with additional specificity and detail through the use of the accompanying drawings, in which:

[0006] Figures 1A to 1C is a block diagram illustrating an example sensor block assembly in various stages of assembly including an isolator rigidly connected to the sensor block for natural frequency suppression to improve sensor performance.

[0007] Figure 2 is an example method for assembling a sensor block assembly for natural frequency suppression to improve sensor performance by rigidly attaching an isolator to the sensor block using adhesive and / or epoxy.

[0008] Figure 3 is an example method for assembling a sensor block assembly for natural frequency suppression to improve sensor performance by rigidly connecting an isolator to the sensor block using welding.

[0009] According to common practice, the various features described are not necessarily drawn to scale, instead emphasis is placed on specific features relevant to the exemplary embodiments. DETAILED DESCRIPTION

[0010] In the following detailed description, reference is made to the accompanying drawings which form a part thereof, and in which specific illustrative embodiments are shown by way of illustration. However, it should be understood that other embodiments may be utilized, and that logical, mechanical, and electrical changes may be made. In addition, the methods presented in the drawings and the specification should not be interpreted as limiting the order in which the various steps may be performed. Therefore, the following detailed description should not be regarded as having a limiting meaning.

[0011] Micro-electro-mechanical systems (MEMS) gyroscopes are susceptible to performance degradation due to the inherent imbalance of their proof-mass, and due to excitation of the surrounding and / or mounting structure of the MEMS gyroscope and the printed board to which the MEMS package is attached, where the excitation is generated by the motor drive of the proof-mass of the gyroscope, which in turn couples back to the proof-mass, excites it, and produces a shift in the bias performance. In other words, the proof-mass of the MEMS gyroscope can be excited by vibrations of its surrounding and / or mounting structure generated by the proof-mass itself, thereby creating a self-excited loop between the proof-mass, the printed board, and the mounting structure. In theory, this problem can be solved by completely isolating the MEMS gyroscope from the external vibration environment, but this is not possible in practice because MEMS gyroscopes cannot be produced under free boundary conditions. Another approach may be to design the mounting structure for the MEMS gyroscope printed board assembly (PBA) so that there are no resonant frequencies below the gyroscope frequency, which may be impossible to achieve or cost prohibitive. Additionally, when designing an inertial sensor assembly having a gyroscope and an accelerometer for guidance and navigation purposes, one typically needs to isolate the sensor assembly from external shock and vibration, which means that one or more isolators typically need to be bolted to the sensor assembly. Introducing such a bolted joint may introduce modes that are detrimental to gyroscope performance. The technology described herein can address the problems introduced by the bolted joint.

[0012] In an example, a technique mitigates or eliminates the resonant frequencies inherent in bolted joints by introducing a structural epoxy (film, liquid adhesive, or other) or welding the bolted components. In an example, this allows production with affordable, manufacturable components. In an example, if the epoxy and / or weld maintain a certain stiffness over temperature and time, the bolted components respond to external vibrations as if they were a single part. In this way, each component on the isolated side of the isolator (such as the inner side) can be designed to avoid any significant resonant modes below the gyroscope frequency. In an example, each component can be manufactured separately and permanently bonded and / or welded during assembly to permanently fix the component to the assembly with sufficient stiffness to mitigate or eliminate any modes associated with the bolted joint. In an example, the technology solves the potential bias performance degradation caused by bolting the joint of the two isolators to the sensor block, but can also be similarly applied to other PBAs that can also be bolted to the same cluster to which the MEMS gyroscope PBA is bolted. The main technical benefit of this technology can be the improvement of gyroscope bias performance while maintaining the manufacturability and affordability of the overall product by eliminating the need for complex geometries or rare materials. In other words, it is a technology that can improve gyroscope bias performance while opening up the design space to ensure cost targets are met.

[0013] In an example, the main mounting structure of the MEMS gyroscope and any additional components on the isolated side (such as the inside) of the elastomer of the isolator (such as the internal metal of the isolator) are designed so that there are no modes below the gyroscope frequency. In an example, a structural epoxy (such as an epoxy film, liquid epoxy, or some other adhesive) or other permanent weld is used to rigidly connect the component to the mounting structure before or after the final fastener torque. In an example, a structural epoxy, liquid epoxy, or other adhesive is applied between the component and the mounting structure, and then mechanical fasteners are tightened between the component and the mounting structure to achieve a more rigid connection between the component and the mounting structure. In an example, mechanical fasteners are tightened between the component and the mounting structure, and then the component is welded to the mounting structure to achieve a more rigid connection between the component and the mounting structure. In an example, two isolators are fastened (such as by bolts, screws, or other fasteners) to the sensor block, where the structural epoxy film is applied before the fasteners are installed. In examples, this technique is also used for bolted joints between other PBAs and blocks, bolted joints between single-ring isolators and blocks, or any other variation described herein.

[0014] As used herein, "rigid connection", "rigid connection", "rigid mechanical connection", etc. refer to non-flexible connections designed to minimize, prevent and / or eliminate movement between connected elements. In contrast, "non-rigid connections" (such as "elastic connections", "flexible connections", etc. formed by elastic materials, etc.) are designed to allow movement between connected elements to provide isolation and / or avoid stress from being transferred from one component to another (such as adhesive stress transferred to MEMS). In some cases, mechanical fasteners and adhesives can be flexible and allow movement between connected elements. In examples, it is desirable to have non-rigid connections (such as elastic connections or flexible connections) between specific elements to provide isolation. In examples, it is desirable to have rigid connections between specific elements. In examples, it is desirable to have non-rigid connections (to provide isolation) between some specific elements while still having rigid connections between some specific elements.

[0015] Figures 1A to 1C is a block diagram illustrating an example sensor block assembly 100 at various stages of assembly, the example system including an isolator rigidly connected to the sensor block with adhesive, epoxy, and / or welding for natural frequency suppression to improve sensor performance. Figure 1A is a block diagram illustrating an example sensor block assembly 100 prior to assembly. Figure 1B is a block diagram illustrating an example sensor block assembly 100 after assembly. Figure 1C 1 is a block diagram illustrating an example sensor block assembly 100 in an embodiment where (1) no screws and / or bolts are used or (2) any screws and / or bolts have been removed after the joint has been welded. In an example, the example system can be implemented on a vehicle or coupled to a vehicle, held by a person, etc. The use of the term "vehicle" is not restrictive and includes all categories of vehicles that fall within the ordinary meaning of the term. This will include, but is not limited to, air-traveling vehicles (e.g., commercial, non-commercial, or recreational aircraft), unmanned and / or space-traveling vehicles (e.g., satellites, urban air mobility vehicles), water-traveling vehicles (e.g., ships, submarines), and land-traveling vehicles (e.g., cars including cars, trucks, motorcycles). Throughout the disclosure, vehicles may be described as aircraft, and it should be understood that the principles described herein are applicable to other applicable vehicles.

[0016] In an example, an example sensor block assembly 100 includes at least one sensor block 102 (having a circuit board and / or circuit card 103, and also referred to as a cluster) and at least one isolator 104 (such as a ring isolator or a four-point mount or eight-point mount isolator). In an example, the circuit board and / or circuit card 103 includes a printed circuit board (PCB). In an example, at least one sensor block 102 includes at least one circuit board and / or circuit card 103 on multiple faces (such as 2, 3, 4, 5, or 6 faces) of at least one sensor block 102. In an example, at least one sensor block 102 includes a single circuit board and / or circuit card 103 on a single face. In an example, the circuit boards and / or circuit cards 103 are connected together into an assembly.

[0017] In an example, at least one sensor block 102 is rigidly connected to at least one isolator 104 by at least one of an adhesive and / or epoxy 106 (and / or welding) to mitigate or eliminate any frequencies that may be transferred from the outside of the sensor block assembly 100 to the at least one sensor block 102. In an example, these frequencies may negatively affect the sensing of the sensors on the sensor block 102. In an example, at least one sensor block 102 is also connected to at least one isolator 104 using at least one mechanical fastener 108 (such as a screw or bolt). In an example, the use of an adhesive and / or epoxy 106 and / or welding stiffens the joint rather than the stiffness when only mechanical fasteners 108 (such as screws or bolts) are used. In an example, at least one mechanical fastener 108 (such as a screw or bolt) is only temporarily used during assembly until the curing of the adhesive and / or epoxy 106 and / or welding is completed to obtain a more rigid connection between the at least one sensor block 102 and the at least one isolator 104, and the at least one mechanical fastener 108 is removed after the curing and / or welding is completed.

[0018] In an example, at least one isolator 104 includes an inner metal 110, wherein an adhesive and / or epoxy 106 (and / or weld) and at least one mechanical fastener 108 are positioned to connect at least one sensor block 102 and at least one isolator 104. In an example, at least one isolator 104 includes an outer metal and an elastomer 112. In an example, the combination of the inner metal 110 and the outer metal and elastomer 112 provides isolation between the at least one sensor block 102 and the base (wider surrounding / mounting structure) in which the example sensor block assembly 100 is positioned, because the outer metal and elastomer 112 isolate between the inner metal 110 and the base (wider surrounding / mounting structure) in which the example sensor block assembly 100 is positioned. In an example, additional components 114 (such as additional circuit boards and / or cards 103) can be mounted to the inner metal 110 for isolation using the adhesive and / or epoxy 106 (and / or weld). In an example, because the at least one isolator 104 is rigidly connected to the at least one sensor mass 102 via adhesive and / or epoxy 106 (and / or welding), movement between the at least one isolator 104 and the at least one sensor mass 102 is minimized.

[0019] Figure 2 An example method 200 for assembling a sensor block assembly using an adhesive and / or epoxy for natural frequency suppression to improve sensor performance is provided. In an example, the method 200 begins at box 202, where at least one of an adhesive or epoxy is applied to at least one of at least one sensor block or at least one isolator. In an example, the method 200 proceeds to box 204, where at least one sensor block and at least one isolator are compressed together using at least one of an adhesive or epoxy between the at least one sensor block and the at least one isolator, where at least one of the adhesive or epoxy forms at least one rigid mechanical connection between the at least one sensor block and the at least one isolator. In an example, the method 200 proceeds to optional box 206, where at least one sensor block and at least one isolator are fastened together using at least one fastener. In an example, the at least one fastener includes at least one of a screw or a bolt. In an example, the method 200 proceeds to box 208, where the adhesive and / or epoxy between the at least one sensor block and the at least one isolator is cured to form at least one rigid mechanical connection between the at least one sensor block and the at least one isolator. In an example, method 200 proceeds to optional block 210 where at least one fastener is removed. In an example, because at least one isolator is rigidly connected to at least one sensor mass via adhesive and / or epoxy, movement between at least one isolator and at least one sensor mass is minimized.

[0020] Figure 3 An example method 300 is to assemble a sensor block assembly using welding for natural frequency suppression to improve sensor performance. In an example, the method 300 starts at box 302, where at least one sensor block is positioned proximate to at least one isolator. In an example, the method 300 proceeds to optional box 304, where at least one sensor block and at least one isolator are fastened together using at least one fastener. In an example, the at least one fastener includes at least one of a screw or a bolt. In an example, the method 300 proceeds to box 306, where at least one sensor block is welded to at least one isolator to form at least one rigid mechanical connection between at least one sensor block and at least one isolator. In an example, the method 300 proceeds to optional box 308, where the fastener is removed after welding at least one sensor block to at least one isolator to form a rigid mechanical connection between at least one sensor block and at least one isolator. In an example, because at least one isolator is rigidly connected to at least one sensor block by welding, movement between at least one isolator and at least one sensor block is minimized.

[0021] Although a detailed description of one or more embodiments of the present disclosure has been given above, various alternatives, modifications and equivalents will be apparent to those skilled in the art without departing from the essence of the present disclosure. For example, although the above-mentioned embodiments relate to specific features, the scope of the present disclosure also includes embodiments with different structural combinations and embodiments that do not include all of the features. Therefore, the scope of the present disclosure is intended to cover all such alternatives, modifications and variations that fall within the scope of the appended claims, as well as all equivalents of the present disclosure. Therefore, the above description should not be considered restrictive.

[0022] Example

[0023] Embodiment 1 includes a sensor block assembly comprising: at least one sensor block; and at least one isolator rigidly connected to the at least one sensor block by at least one of an adhesive, an epoxy, or a weld.

[0024] Embodiment 2 includes the sensor block assembly of embodiment 1, wherein the at least one isolator is further connected to the at least one sensor block by at least one fastener.

[0025] Embodiment 3 includes the sensor block assembly of embodiment 2, wherein the at least one fastener comprises at least one of a screw or a bolt.

[0026] Embodiment 4 includes the sensor block assembly of any one of Embodiments 1 to 3, wherein the at least one isolator comprises a plurality of isolators.

[0027] Embodiment 5 includes the sensor block assembly of any one of Embodiments 1 to 4, wherein at least one sensor block includes at least one circuit board on at least one side.

[0028] Embodiment 6 includes the sensor block assembly of any one of embodiments 1 to 5, wherein movement between at least one isolator and at least one sensor block is minimized because at least one isolator is rigidly connected to at least one sensor block by at least one of an adhesive, epoxy, or welding.

[0029] Embodiment 7 includes a method of assembling a sensor block assembly, the method comprising: applying at least one of an adhesive or an epoxy to at least one of at least one sensor block or at least one of at least one isolator; and compressing the at least one sensor block and the at least one isolator together using the at least one adhesive or the epoxy between the at least one sensor block and the at least one isolator, wherein the at least one adhesive or the epoxy forms at least one rigid mechanical connection between the at least one sensor block and the at least one isolator.

[0030] Embodiment 8 includes the method of embodiment 7, further comprising: curing at least one of the adhesive or the epoxy between the at least one sensor block and the at least one isolator to form the at least one rigid mechanical connection between the at least one sensor block and the at least one isolator.

[0031] Embodiment 9 includes the method of any one of Embodiments 7 to 8, further comprising: fastening the at least one sensor block and the at least one isolator together using at least one fastener.

[0032] Embodiment 10 includes the method of Embodiment 9, wherein the at least one fastener comprises at least one of a screw or a bolt.

[0033] Embodiment 11 includes the method described in any one of Embodiments 9 to 10, further comprising: curing at least one of the adhesive or the epoxy resin between the at least one sensor block and the at least one isolator to form the at least one rigid mechanical connection between the at least one sensor block and the at least one isolator.

[0034] Embodiment 12 includes the method of Embodiment 11, further comprising removing the at least one fastener after curing at least one of the adhesive or the epoxy between the at least one sensor mass and the at least one isolator.

[0035] Embodiment 13 includes the method of any one of Embodiments 7 to 12, wherein the at least one isolator comprises a plurality of isolators.

[0036] Embodiment 14 includes the method of any of Embodiments 7 to 13, wherein movement between the at least one isolator and the at least one sensor mass is minimized due to at least one rigid mechanical connection between the at least one sensor mass and the at least one isolator.

[0037] Embodiment 15 includes a method of assembling a sensor block assembly, the method comprising: positioning at least one sensor block proximate to at least one isolator; and welding the at least one sensor block to the at least one isolator to form at least one rigid mechanical connection between the at least one sensor block and the at least one isolator.

[0038] Embodiment 16 includes the method of Embodiment 15, further comprising: fastening the at least one sensor block and the at least one isolator together using at least one fastener before welding the at least one sensor block to the at least one isolator.

[0039] Embodiment 17 includes the method of embodiment 16, wherein the at least one fastener comprises at least one of a screw or a bolt.

[0040] Example 18 includes the method of Example 17, further comprising removing the at least one fastener after welding the at least one sensor mass to the at least one isolator.

[0041] Embodiment 19 includes the method of any one of Embodiments 15 to 18, wherein the at least one isolator comprises a plurality of isolators.

[0042] Embodiment 20 includes the method of any one of Embodiments 15 to 19, wherein movement between the at least one isolator and the at least one sensor mass is minimized due to at least one rigid mechanical connection between the at least one sensor mass and the at least one isolator.

Claims

1. A sensor block assembly, the sensor block assembly comprising: at least one sensor block; and At least one isolator is rigidly connected to the at least one sensor mass by at least one of an adhesive, an epoxy, or a weld.

2. A method of assembling a sensor block assembly, the method comprising: applying at least one of an adhesive or an epoxy to at least one of the at least one sensor mass or the at least one isolator; as well as The at least one sensor mass and the at least one isolator are compressed together using the at least one of the adhesive or the epoxy between the at least one sensor mass and the at least one isolator, wherein the at least one of the adhesive or the epoxy forms at least one rigid mechanical connection between the at least one sensor mass and the at least one isolator.

3. A method of assembling a sensor block assembly, the method comprising: positioning at least one sensor mass proximate to at least one isolator; as well as The at least one sensor mass is welded to the at least one isolator to form at least one rigid mechanical connection between the at least one sensor mass and the at least one isolator.

Images