Structural Design and Vibration Resistance Analysis of MEMS IMU

MEMS Inertial Measurement Units (MEMS IMUs) are widely used in fields such as navigation and attitude control; however, vibration environments can significantly degrade their measurement accuracy. Research indicates that external vibrations can cause severe output deviations in MEMS gyroscopes and may even lead to structural fatigue or fracture. Consequently, employing rational structural design and vibration-resistance optimization at the system level is crucial for enhancing the environmental adaptability of MEMS IMUs.

**Vibration Interference Mechanisms and Design Objectives**

The fundamental reason for the vibration sensitivity of MEMS IMUs lies in their operating principles. Taking the gyroscope as an example, its operation relies on the coupling between drive and sense modes; if external vibrations couple into these modes, they directly translate into output errors. Furthermore, structural resonance induced by vibration amplifies this effect. Therefore, structural design pursues two core objectives: first, avoiding resonance by using modal analysis to ensure the structure's natural frequencies remain well away from the frequency bands where vibration energy is concentrated; and second, isolating vibration by incorporating vibration-isolation elements along the transmission path to attenuate the vibration energy reaching sensitive components.

**Key Structural Design Strategies**

Current structural design approaches primarily follow two technical paths:

First, system-level vibration isolation structures. Vibration isolation systems are created by embedding isolators (such as rubber pads or metal springs) between the IMU and the host platform, or between the internal core and the outer housing. Research suggests that to meet the compact size requirements of MEMS IMUs, multi-stage isolation designs can be employed—such as arranging three levels of damping pads (housing–core–measurement assembly) and utilizing stiffness gradients to achieve staged attenuation. More advanced solutions utilize motion-decoupling mechanisms to design six-degree-of-freedom isolation systems, thereby suppressing vibration coupling effects caused by isolator asymmetry. In typical applications, the use of a two-stage lattice isolation structure combined with redundant, multi-sensor 3D mounting can reduce the root-mean-square (RMS) value of angular velocity output by more than 88% under flight vibration spectra.

Second, optimization of sensitive structures. At the chip level, vibration resistance can be enhanced at the source by employing high-symmetry structural designs (such as eight-mass or ring structures) that utilize differential principles to cancel out common-mode vibration interference, or by using a single-mass tri-axial gyroscope design featuring a central anchor and symmetric flexure bearings.

Design Verification and Performance Evaluation

Finite element analysis (FEA) serves as the most critical verification tool in this field. Modal analysis allows for the calculation of natural frequencies to assess resonance risks, while frequency response and random vibration analyses predict acceleration responses under specific power spectral densities, providing a basis for design iteration. Experimental verification typically encompasses calibration and vibration testing. For instance, one optimized design—utilizing methods such as adding support beams and reducing fixed spans—more than doubled the vibration resistance of the IMU compared to the original design; another lightweight IMU demonstrated excellent vibration resistance alongside high precision during vibration testing.

In summary, the vibration resistance of MEMS IMUs is a system-level issue that requires a structural dynamics perspective and the integrated application of techniques such as modal analysis, vibration isolation design, and optimization simulation. Adopting "avoiding resonance" and "efficient vibration isolation" as core design principles offers an effective pathway for developing highly reliable MEMS IMUs. Looking ahead, advancements in materials science and control algorithms will enable MEMS IMUs to maintain performance in increasingly extreme vibration environments, opening up broader application prospects.