Programmable materials create multistable motor-less finger for robotics

Researchers at the Fraunhofer Cluster of Excellence Programmable Materials (CPM) have developed a novel finger joint made from a single piece of programmable metamaterial, called the ProFi (Programmable Multistable Finger) project. This motor-less finger can lock into four stable positions without the need for screws, hinges, or multiple interconnected parts, simplifying the design of hand prostheses and robotic grippers. The finger bends along one axis in 30-degree increments, enabling distinct gripping, resting, or gesturing positions. The design was validated through finite element method simulations to ensure durability and stiffness, and was produced using additive manufacturing techniques like Fused Deposition Modeling and Selective Laser Sintering, allowing for easier customization and assembly-free fabrication. The key innovation lies in the integration of bistable unit cells—elastic beams that snap between stable states without continuous force—within the joint’s internal structure. Using specialized software (ProgMatCode), researchers optimized these cells to create a passive multistable mechanism