基于绳牵引结构的高性能微型压电振动能量收集器研究

Piezoelectric vibration energy harvester is highlighted as a new solution of wireless sensor network for the realization of passive power supply due to the advantages of easy integration with MEMS, no extra power supply and simple structure. However, it is hardly to achieve the features of low frequency, wideband and effective output power in energy harvesting for traditional micro piezoelectric vibration energy harvesters. In this project, a novel ropes-driven piezoelectric vibration energy harvester is proposed to achieve low frequency, wideband and highly efficient energy harvesting through adopting a structure of multi beams driving single piezoelectric beam and c-axis tilted AlN film as the piezoelectric material, using the nonlinear vibration mechanism, and combining the optimization of structure and material. A nonlinear spring damping model was built up for this energy harvester, and its’ energy transfer and wideband mechanisms were revealed by the investigation of rigid-flexible coupling nonlinear dynamic behavior of single/multi beams driving structure using numerical simulation and large scale prototype experiments. The electromechanical coupling characteristics of c-axis tilted AlN film beam were investigated to enhance the electromechanical conversion efficiency. The growth mechanism of c-axis tilted AlN film was studied, and the novel energy harvester based on MEMS technology was fabricated and tested. This project will provide a new idea to achieve low frequency, wideband and high efficiency MEMS piezoelectric vibration energy harvester and promote the development of energy harvesting technologies.

微型压电振动能量收集器因具有与MEMS工艺集成性好、无需启动电源及结构简单等优点，为无线传感器网络实现自供能提供了新的解决方案。针对目前微型压电振动能量收集器存在难以兼具低频、宽频带、高效输出的问题，本项目提出了一种基于绳牵引的新型压电振动能量收集器，以多梁牵引单压电梁的结构为突破点，依托绳牵引的非线性振动机制，采用c轴倾斜AlN薄膜为能量收集载体，结合结构和材料优化设计实现兼具低频、宽频带、高效输出性能的能量收集。通过构建非线性弹簧阻尼模型，借助数值仿真并结合大尺度样机实验验证，研究单/多梁牵引结构的刚柔耦合非线性动力学行为，揭示能量传递机制和拓频机理；研究c轴倾斜AlN薄膜受迫梁机电耦合特性，提升机电转化效率；研究c轴倾斜AlN薄膜生长调控机制，实现能量收集器MEMS制备并完成性能测试。本项目的实施将为低频、宽频带、高效微型压电振动能量收集器实现提供新思路，进一步促进能量收集技术发展。

微型压电振动能量收集器是解决无线传感器网络自供能问题的重要研究方向，如何开发能应用于低频环境且具备宽频带能量收集能力的高性能压电振动能量收集是其面向实际应用的首要前提。本项目创造性地提出了一种基于绳牵引的新型压电振动能量收集器，引入非线性机制，从器件机理、结构、材料三个方面积极开展相关的研究工作，具体研究内容为：1、基于绳牵引结构的非线性动力学研究。2、基于c轴倾斜AlN薄膜受迫梁输出性能优化。3、基于绳牵引结构的压电振动能量收集器微型化实现。重要研究结果如下：. 1、首次把柔性体——绳子应用于振动能量收集器的设计，提出基于绳牵引结构的新型压电振动能量收集器，依托刚柔耦合结构的非线性机制，可以有效地实现低频、宽频能量收集。. 2、建立基于绳牵引结构的压电振动能量收集器的刚柔耦合非线性动力学模型和仿真体系，提取激励加速度、绳子余量、绳子刚度等主要影响参数，研究各参数对能量收集器性能的影响规律，通过实验验证了该模型的准确性和有效性，为能量收集器的应用开发提供技术支持。. 3、提出新的优化机制——碰撞和绳牵引的混合机制，建立基于混合机制的动力学模型，给出了适合基于绳牵引结构的微型压电振动能量收集器性能提升的优化方案。. 4、提出基于c轴倾斜的AlN微型低频宽频压电振动能量收集器的优化方案，结果表明对于几何尺寸固定的压电悬臂梁，优化c轴倾斜角能够提升3倍的能量输出。. 5、针对实际应用中的多方向振动能量收集需求，提出基于液体俘能的新机制，实现低频（2.6Hz）低强度（0.03g）多方向（水平360度）能量收集；提出基于俘能球体的绳牵引低频多方向低强度振动能量收集器，实现低频(<10Hz)、三维多方向、低强度（0.02g）能量收集。. 本项目的成果将为低频、宽频带、高效微型压电振动能量收集器实现提供新思路，进一步促进能量收集技术发展。