4 results about "Internal resonance" patented technology

This invention relates to the field of wave energy generation, and more particularly to a dual-frequency high-efficiency energy harvesting method for a spring pendulum wave energy generator. The energy harvesting method includes the following steps: the spring pendulum wave energy generator enters the working state and directly contacts seawater, moving in undulating motion with the waves; the two directional degrees of freedom of the spring pendulum wave energy generator are adjusted; the spring pendulum wave energy generator uses a swing arm to adjust the resonant frequency of the oscillation degree of freedom of the float; the spring pendulum wave energy generator uses the resonant frequency of the hemispherical float and the spring-adjusted float along the radial degree of freedom of the long swing arm; a spring is added to the swing arm to make it a nonlinear spring pendulum structure, and its internal resonance characteristics are used to realize the mutual switching of the float's kinetic energy between the oscillation and radial degrees of freedom.

The application relates to a MEMS gyro array error suppression device and method based on active piezoelectric excitation. The MEMS gyro array error suppression device and method based on active piezoelectric excitation designed by the application applies controlled low-frequency micro-amplitude mechanical vibration to the MEMS gyro array through a piezoelectric exciter, physically modulates the internal resonance state of the gyroscope to reduce the time correlation of the scale factor error, and converts systematic deviation into random noise. In combination with a base matched in terms of thermal expansion coefficient and double-mode signal processing, the device can separate effective signals while suppressing thermal stress interference, so that the array fusion algorithm can eliminate common-mode errors, and the measurement precision is improved to within 0.5 degrees without changing the sensor process.

This invention relates to the field of vibration control technology and discloses a structural coupling vibration isolation system and method for cleanrooms. The system is installed on the floor slab of a building structure and includes an isolation support frame system, a quasi-zero stiffness main support unit, a segmented viscous damper, and a nonlinear tuned mass damping module. The isolation support frame is lowered in the middle to form a suspended foundation pit. The quasi-zero stiffness unit effectively isolates external low-frequency vibrations. The segmented damper achieves low-resistance, high-energy-dissipation limiting for micro-vibrations and large displacements. The equipment base acts as a tuned mass block to adaptively absorb internal resonant energy. This invention, by constructing a coordinated structural coupling vibration control system, can simultaneously achieve ultra-low frequency vibration isolation, wideband adaptive vibration absorption, and seismic safety protection, making it suitable for micro-vibration control scenarios of precision equipment in semiconductor cleanrooms.

This invention discloses a method for identifying internal resonance in flexible structures based on acoustic measurements, comprising: 1. Calculating the natural frequencies and mode shapes of the flexible structure through dynamic modeling and eigenvalue solving to determine that the structure has approximately reducible mode frequencies, satisfying the preconditions for internal resonance; 2. Arranging several sound pressure sensors near the flexible structure to collect the time-domain signal of the dynamic radiated sound pressure of the structure; 3. Using fast Fourier transform to extract the sound pressure amplitude of each sound pressure sensor near a certain low-order natural frequency, and plotting the directivity curve of the sound pressure amplitude with respect to the spatial position of the sensor. By comparing the directivity curve with the geometric characteristics of the mode shapes of the flexible structure, it is determined whether the structure is in an internal resonance state. This invention can identify whether the low-order coupling modes of the flexible structure are excited by monitoring the spatial directivity curve of the radiated sound pressure of the flexible structure, thereby achieving accurate and intuitive identification of internal resonance phenomena in flexible structures through non-contact, simple, and convenient acoustic measurements.