Selective Unit-Cell Actuation in Lattice Structures for Distributed Morphology in Soft Robots

2026-06-17

AI Summary

This work addresses the challenge of achieving fine-grained, distributed shape control in conventional soft robots by proposing a unit-level co-design approach. For the first time, bidirectional bellows actuators and curved beam structures are integrated within individual lattice units, enabling spatially selective deformation through embedded pneumatic actuation. The design facilitates heterogeneous unit assembly and selective pressure control, allowing diverse global deformation patterns to be generated without hardware reconfiguration. The method’s scalability, cyclic stability, and morphological versatility are demonstrated in a 3×3×3 array, which successfully executes bending, directional grasping, and asymmetric crawling via active-passive coupled actuation.

Abstract

Soft lattice structures are increasingly used in robotics to tailor compliance and guide deformation; however, actuation is typically introduced at the device or module level, with actuators inserted into otherwise passive architectures. In this work, we move actuator-lattice co-design to the unit-cell scale. We present an embedded pneumatic unit cell that integrates curved-strut lattice geometry with a bidirectional bellow actuator within a single monolithic element. When tessellated, the lattice functions as a distributed actuation field in which global morphology is governed by spatial actuation patterns rather than uniform pressurization. Experimental characterization of 1x1, 2x2, and 3x3 tessellations demonstrates scalable displacement and force generation with repeatable cyclic performance. Selective actuation of unit cells in a 3x3x3 array produces distinct global deformation modes, including bending and directional grasping, without altering hardware configuration. Additionally, coupling active and passive unit cells enables bending-driven crawling locomotion, demonstrating that heterogeneous tessellations can translate through asymmetric deformation. These results establish unit-cell-level actuation as a strategy for distributed morphing in lattice-based soft robots and provide a foundation for scalable, monolithic robotic architectures.

Problem

• lattice structures
• soft robots
• distributed morphology
• unit-cell actuation
• selective actuation

Innovation

• unit-cell actuation
• lattice structures
• soft robotics
• distributed morphing
• monolithic design