Adjustable Stopper Gap for Wideband Piecewise-Linear Vibration Control
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Solution Overview
Problem
Existing vibration energy harvesters are limited to narrow frequency ranges and do not achieve optimal efficiency at varying frequencies, with linear designs performing best at resonance and nonlinear designs being less efficient.
Innovation Solution
A device and method incorporating piecewise-linear nonlinearity with adjustable gap sizes, using a stiffness element, mass, stopper, and actuator, controlled by a controller to optimize gap size based on excitation frequency and amplitude, employing bilinear amplitude approximation for efficient vibration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If linear energy harvesters are used, then maximum power generation efficiency is achieved at resonance, but the effective frequency bandwidth is very narrow
Solution Approach 1:
The patent applies piecewise-linear nonlinearity by incorporating mechanical stoppers that create gap-based nonlinear stiffness. The system dynamically transitions between linear and nonlinear regimes based on excitation amplitude, allowing the resonant frequency to shift and accommodate a broader frequency range while maintaining high power generation efficiency at resonance.
Solution Approach 2:
The patent changes the stiffness parameter by introducing piecewise-linear nonlinearity through mechanical stoppers. The effective stiffness of the system changes based on the gap size and excitation amplitude, enabling the system to adapt its resonant frequency to match varying excitation frequencies while maintaining high efficiency.
2Adaptability or versatility
If nonlinear energy harvesters are used to broaden frequency bandwidth, then effective frequency range is increased, but power generation efficiency decreases compared to linear harvesters at resonance
Solution Approach 1:
The patent uses piecewise-linear nonlinearity where the system remains linear for small amplitudes (maintaining high efficiency at resonance) but transitions to nonlinear behavior for larger amplitudes (broadening frequency range). This dynamic transition allows the system to achieve both high efficiency and broad bandwidth depending on operating conditions.
3Adaptability or versatility
If array-harvester systems are used, then vibration energy can be harvested over multiple resonant frequencies, but system setup and electronic configuration become complex
Solution Approach 1:
Instead of using multiple separate linear harvesters (array system), the patent segments the stiffness characteristic into piecewise-linear segments using mechanical stoppers. This creates a single harvester with nonlinear stiffness that effectively covers multiple frequency ranges, avoiding the complexity of multiple harvesters while achieving similar frequency coverage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient vibration performance across a wide frequency range by tuning resonant frequencies, maintaining high performance at resonance, and adapting to varying excitation conditions.
Implementation Method 1
a stiffness element. The stiffness element is expandable and compressible along the axis
Implementation Method 2
a mass, The mass is coupled to the stiffness element
Data Source
AI summary
Various implementations include a device for controlling vibration with piecewise-linear nonlinearity. The device includes a stiffness element, a mass, a stopper, and an actuator. The stiffness element is expandable and compressible along an axis. The mass is coupled to the stiffness element. The mass has a resting mass position along the axis. The actuator is coupled to the stopper. The actuator is configured to move the stopper along the axis to vary a gap size. The gap size is measured as a distance between the resting mass position and a resting stopper position.