基于压电双晶片材料的微型仿生扑翼机能效提升研究

The bionic flapping-wing unmanned aerial vehicles (BFW-UAVs) are served as critical carrier in the fields of environmental monitoring, geological exploration, personnel rescue, as well as agricultural production. Micro electromechanical systems (MEMS) technology significantly promotes the development of BFW-UAVs toward miniaturization direction. The project makes a breakthrough in traditional driving method that utilizes micro-motors to drive wing to flap repeatedly, innovative adopts sub-centimeter piezoelectric bimorph materials (PBMs) as artificial muscle to transform energy converter output voltage into resonant mechanical deformation that can be amplified via high efficient multi-degree of freedom (MDOF)transmission mechanical structure to propel airfoil to generate enough elevating force, focuses on the energy efficiency promotion of BFW-UAVs. The main purpose of the research is establishing and improving the efficiency of ornithopter unsteady aerodynamic model at low reynolds number, optimizing the driving parameters and control strategy of PBMs with sandwich structure, pursuing the optimal topology, control scheme and performance of the “hybrid PWM/PFM” energy conversion based on die ASIC technology, building high coupling-efficient mechanical structure which can transform the resonant mechanical motion of PBMs into MDOF rotary motion of wing. Ultimately, the energy efficiency of BFW-UAVs can be promoted to 53%, which makes BFW-UAV can be widely utilized in military and civilian fields.

在环境监测、地质勘查、人员营救、以及农业生产等领域，扑翼式仿生无人机为重要载体。微电子机械系统（MEMS）技术的引用很大程度上促进着仿生扑翼机朝着微型化方向发展。本项目突破国际上采用微型马达驱动翅膀往复煽动的传统思想，创新性地引入亚厘米级高能效压电双晶片 “人造肌肉”，将高转换效率能量转换器输出驱动电压转换为谐振机械形变，通过多自由度传动式高能效机械结构进行行程放大，驱动机翼产生足够的升力，来研究微型仿生扑翼机能效提升问题。主要研究低雷诺系数下微型扑翼机非定常气动模型及其气动效率提升问题；“三明治”结构的压电双晶片材料驱动性能参数及控制策略寻优问题；裸晶ASIC工艺“混合型PWM/PFM”的能量转换拓扑结构、控制方案以及性能指标优化问题；从压电双晶片谐振机械运动到机翼多自由度旋转运动的传动式高能效机械结构耦合问题；最终微型仿生扑翼机能的效提升到53%，并且能够在军、民领域中得到广泛应用。

本项目突破国际上采用微型马达驱动翅膀往复煽动的传统思想，创新性地引入亚厘米级高能效压电双晶片 “人造肌肉”，将高转换效率能量转换器输出驱动电压转换为谐振机械形变，通过多自由度传动式高能效机械结构进行行程放大，驱动机翼产生足够的升力，提升微型仿生扑翼机能效。首先分析并建立了低雷诺系数下微型扑翼机非定常气动模型，进行了N-S方程求解，获得了昆虫翅膀在运动过程中周围的压力场、速度场以及相应的非稳态涡流场。研究了不同特征参数对升阻力的影响，主要参数包括扑翼攻角、扑翼振幅、振翅频率及飞行速度、起始位置等。进行了压电双晶片材料驱动参数的研究和控制策略寻优，提出了简化Bouc-Wen模型以及相应的参数辨识方法，并确定了参数整定方案，传递能效大于90%。提出了两种能量转换电路拓扑：级联抽头电感升压驱动转换器和基于压电变压器的升压驱动转换器，最高能效达到68.5%。确定了高能效传动机械结构各项参数和激光加工方案，依托碳纤维-聚酯膜-碳纤维“三明治”结构实现了铰链-杆件高能效传动机，能效大于90%。研制了微型扑翼机样机，翼展约2 cm，整机质量小于3 g。调整样机参数后进行了室外测试，总体能效达到55.5%。结合小型锂电池，达到了续航时间48 min，巡航半径1.4 km的指标要求。项目执行期间发表SCI论文4篇，EI论文1篇，授权国家发明专利3项。