Response Speed Characterization of a Thermally Actuated Programmable Metamaterial

This work details the experimental characterization of a MEMS thermal actuator, which constitutes a three-dimensional meso-robotic metamaterial lattice that can achieve actively controlled mechanical properties such as tunable stiffness. To achieve a target stiffness value via closed-loop control in a timeframe that is practical for most metamaterial applications, it is necessary that such actuators can rapidly respond to the controller’s commands. In this letter, a fabricated thermal actuator experimentally demonstrates the ability to achieve desired stiffness values within 100s of milliseconds of receiving the command signal. The actuator can also maintain those stiffness values regardless of changing external loading conditions with acceptable accuracy. Thus, the results of this work prove that the metamaterial design can enable practical applications such as surgical tools that can change from compliant to stiff states as they perform their functions within the body and materials that can tune their natural frequencies to enable technologies that leverage resonant actuation such as steerable mirrors and optical switches. [2023-0150]

这项工作详细描述了一种微机电系统（MEMS）热致动器的实验特性，它构成了一种三维介观机器人超材料晶格，能够实现诸如可调刚度等主动控制的机械性能。为了在对大多数超材料应用实际可行的时间范围内通过闭环控制达到目标刚度值，这种致动器必须能够对控制器的指令迅速做出响应。在本文中，一个制造出来的热致动器通过实验证明了在接收到指令信号后的100毫秒内达到期望刚度值的能力。无论外部负载条件如何变化，该致动器还能够以可接受的精度保持这些刚度值。因此，这项工作的结果证明，超材料设计能够实现实际应用，比如手术工具在体内执行功能时能够从柔顺状态变为刚性状态，以及材料能够调整其固有频率，从而使诸如可转向反射镜和光开关等利用共振驱动的技术成为可能。[2023 - 0150]