A novel nonlinear compliant link on simple grippers

This paper presents a novel nonlinear compliant link. It has two major properties: bi-directionality and stiffening compliance. Bi-directionality means it can be stretched and compressed, and is realized by antagonistic arrangement of an extension spring and a compression spring. Stiffening compliance means it becomes stiffer as it is stretched, and is realized by asymmetric geometry. The links are parts of Simple Hand. Because Simple Hand gives limited space for links, current iteration of links is not obviously nonlinear. However, nonlinearity should be more obvious if links are designed for larger grippers.

I. Introduction

Compliance is common and important in human manipulation. Soft muscles and tendons give human hands the ability to adjust passively to target objects. Moreover, these soft tissues absorb shocks when one hammers a nail or catches a flying frisbee, protecting the body. In addition to passive ways, humans use active compliance, employing neural mechanisms in control [1] [2].