SpiRobs copies an octopus arm with a logarithmic spiral
Originally posted on LinkedIn, September 11, 2025.
An octopus can twist, fold, and curve each arm into almost any shape, without joints or bones. A group of researchers set out to reproduce that ability with a robotic arm called SpiRobs.
At first glance, it looks like a flexible 3D-printed toy. Behind that simplicity is a mathematical idea: a logarithmic spiral structure that lets the arm bend across a wide range of shapes while applying force precisely.
The result is an arm that can grip objects across a size range spanning more than two orders of magnitude and carry up to 260 times its own weight.
What interests me is not only the engineering, but the principle behind it. Instead of building another rigid arm with more joints and motors, the engineers copied a natural pattern tested over millions of years of evolution. It combines biomimicry with simple, inexpensive manufacturing through 3D printing.