Robotic Metamaterials with Reprogramming and Information-Processing Capabilities

Date: 2024/04/22 - 2024/04/22

Dissertation Title: Robotic Metamaterials with Reprogramming and Information-Processing Capabilities

Speaker: Bihui Zou, Ph.D. candidate at UM-SJTU Joint Institute

Time: April 22 from 3:00 p.m., 2024 (Beijing Time)

Location: Room 414B, Longbin Building


Robotic metamaterials, which are created by combining mechanical metamaterials with active materials, exhibiting unique physical properties rarely found in the natural world. Additionally, they distinguish themselves as robotic matters capable of sensing, thinking, and actuating, owing to their capacities for reconfiguration, reprogrammability, and information processing. However, as an emerging field, designing robotic metamaterials with these characteristics still presents several challenges, including the irreversible and shape-holding problems of reconfiguration, the requirement for high energy input for the current reprogramming method, the intricate structure for mechanical computing and the separation of arithmetic and memory units. In this thesis, the author aims to advance the field of robotic metamaterials by addressing the aforementioned challenges through the integration of structural mechanics and material characteristics. The author develops magneto-thermomechanical robotic metamaterials by embedding permanent magnets into 3D printing SMP lattices and actuating them in a thermal-magnet field. Reversible and shape-locking transformations can be achieved due to the shape memory effect and the coupling between a localized magnetic torque with the prestressing of SMP lattice structures. Then the author proposes a reprogramming strategy for multimodal transformation based on structural instability and symmetry-breaking magnetic arrangement. This strategy allows for the realization of various deformation modes by manipulating the direction of magnetic fields. To gain a deeper understanding of the underlying principles behind the reprogramming strategy and to achieve more precise control over multimodal transformations, the author developed an analytical model that incorporates the interaction between instability and external magnetic torque. This model enables precise predictions of multimodal and multistep transformations while also revealing the factors that influence these transformations. Finally, the author proposes a straightforward and modularized design strategy for pure mechanical computing with logic-in-memory based on structural instability. All logic operations are encapsulated into various mechanical logic gate modules and the signal transfer rules are investigated, facilitating the construction of complex computation device by direct invocation of different module units. Different from the previous designs for robotic metamaterials which focus on new material synthesis to achieve reconfiguration, reprogramming and intelligence properties, this thesis offers a paradigm shift in the design by primarily using structural mechanics. This approach paves the way for new possibilities in designing future robotic metamaterials and enhances their potential applications across diverse fields, such as aerospace, robotics, and electronics.


Bihui Zou received the B.S. degree in composite materials and engineering from Northwestern Polytechnical University in 2019. She is currently a Ph.D. candidate at the UM-SJTU Joint Institute, supervised by Prof. Jaehyung Ju. Her current research interests include mechanical metamaterials, active materials, and 4D printing.