Du Yangyang, Wu Xiaojun, Wang Dan, Zhao Futeng, Hu Hua
School of Mechanical and Electrical Engineering, Xi'an University of Architecture and Technology, Xi'an 710049, China.
Department of Mechanical and Electrical Engineering, Yuncheng University, Yuncheng 044000, China.
Biomimetics (Basel). 2024 Aug 13;9(8):488. doi: 10.3390/biomimetics9080488.
Inspired by the fact that flying insects improve their power conversion efficiency through resonance, many soft robots driven by dielectric elastomer actuators (DEAs) have achieved optimal performance via first-order modal resonance. Besides first-order resonance, DEAs contribute to multiple innovative functions such as pumps that can make sounds when using multimodal resonances. This study presents the multimodal resonance of a rectangular planar DEA (RPDEA) with a central mass bias. Using a combination of experiments and finite element modeling (FEM), it was discerned that under a prestretch of 1.0 × 1.1, the first-, second-, and third-order resonances corresponded to vertical vibration, rotation along the long axis, and rotation along the short axis, respectively. In first-order resonance, superharmonic, harmonic, and subharmonic responses were activated, while only harmonic and subharmonic responses were observed in the second- and third-order resonances. Further investigations revealed that prestretching tended to inhibit third-order resonance but could elevate the resonance frequencies of the first and second orders. Conveniently, both the experimental and FEM results showed that the frequencies and amplitudes of the multimodal resonances could be tuned by adjusting the amplitudes of the excitation signals, referring to the direct current (DC) amplitude and alternating current (AC) amplitude, respectively. Moreover, instead of linear vibration, we found another novel approach that used rotation vibration to drive a robot with soft bristles via hopping locomotion, showcasing a higher speed compared to the first-order resonance in our robot.
受飞行昆虫通过共振提高其功率转换效率这一事实的启发，许多由介电弹性体致动器（DEA）驱动的软机器人已通过一阶模态共振实现了最佳性能。除了一阶共振外，DEA还具备多种创新功能，例如使用多模态共振时能发出声音的泵。本研究展示了具有中心质量偏置的矩形平面DEA（RPDEA）的多模态共振。通过实验和有限元建模（FEM）相结合的方法，发现在1.0×1.1的预拉伸下，一阶、二阶和三阶共振分别对应垂直振动、沿长轴旋转和沿短轴旋转。在一阶共振中，超谐波、谐波和亚谐波响应被激活，而在二阶和三阶共振中仅观察到谐波和亚谐波响应。进一步研究表明，预拉伸倾向于抑制三阶共振，但可以提高一阶和二阶的共振频率。方便的是，实验和有限元模拟结果均表明，多模态共振的频率和振幅可分别通过调整激励信号的振幅（分别指直流（DC）振幅和交流（AC）振幅）来调节。此外，我们发现了另一种新颖的方法，即利用旋转振动通过跳跃运动驱动带有软刷毛的机器人，与我们机器人中的一阶共振相比，其展示出更高的速度。
