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]