Novel Spring Mechanism Enables Iterative Energy Accumulation under Force and Deformation Constraints

TL;DR

This paper introduces a novel floating spring mechanism that allows iterative energy accumulation over multiple cycles, overcoming traditional force and deformation limits, and enabling more efficient assistive devices for humans and robots.

Contribution

A new floating spring design decouples compression force from energy storage, allowing repeated energy accumulation beyond conventional spring constraints.

Findings

Enables energy storage over multiple cycles with a single spring.

Decouples force application from energy storage in springs.

Potential to reduce actuator size in assistive robotics.

Abstract

Springs can provide force at zero net energy cost by recycling negative mechanical work to benefit motor-driven robots or spring-augmented humans. However, humans have limited force and range of motion, and motors have a limited ability to produce force. These limits constrain how much energy a conventional spring can store and, consequently, how much assistance a spring can provide. In this paper, we introduce an approach to accumulating negative work in assistive springs over several motion cycles. We show that, by utilizing a novel floating spring mechanism, the weight of a human or robot can be used to iteratively increase spring compression, irrespective of the potential energy stored by the spring. Decoupling the force required to compress a spring from the energy stored by a spring advances prior works, and could enable spring-driven robots and humans to perform physically demanding tasks without the use of large actuators.