High-energy-density 3D-printed Composite Springs for Lightweight and Energy-efficient Compliant Robots

TL;DR

This paper introduces a novel 3D printed torsional spiral spring with 45% higher energy density, enabling lightweight, energy-efficient compliant robots by optimizing internal structure for better energy storage.

Contribution

The paper presents a new design and structural optimization method for 3D printed springs, significantly increasing their energy density compared to traditional designs.

Findings

45% increase in mass energy density over uniform springs

Potential for robots to recycle more mechanical energy

Reduction in energy required for robot control

Abstract

Springs store mechanical energy similar to batteries storing electrical energy. However, conventional springs are heavy and store limited amounts of mechanical energy relative to batteries, i.e they have low mass-energy-density. Next-generation 3D printing technology could potentially enable manufacturing low cost lightweight springs with high energy storage capacity. Here we present a novel design of a high-energy-density 3D printed torsional spiral spring using structural optimization. By optimizing the internal structure of the spring we obtained a 45% increase in the mass energy density, compared to a torsional spiral spring of uniform thickness. Our result suggests that optimally designed 3D printed springs could enable robots to recycle more mechanical energy per unit mass, potentially reducing the energy required to control robots.