Model Identification of a Soft Robotic Neck

Abstract

Soft links and actuators are nowadays emerging technologies aiming to overcome some problems in robotics such as weight, cost or human interaction. However, the nonlinear nature of their elements can make their characterization challenging and hinder the use of standard control engineering tools. In this paper, we explore different state-of-the-art identification methods for the soft neck, in order to find a reliable plant model. Even though the neck has three Degrees of freedom, in this work we only consider the planar deflection of the link as a starting point for future analysis. Given the nonlinear nature of the soft neck, we consider two identification strategies, i.e., set membership, which is a data driven, nonlinear and nonparametric identification strategy, and Recursive Least Squares at selected linearization points. A neural network identification is also given for comparison purposes. Results show that the explored methods offer a suitable alternative to identify the dynamics of the neck that allows their implementation for simulation and future control.