Data-driven Kinematic Modeling in Soft Robots: System Identification and Uncertainty Quantification

TL;DR

This paper explores data-driven machine learning methods for soft robot kinematic modeling, emphasizing the importance of uncertainty quantification, and introduces a conformal prediction framework to provide reliable uncertainty estimates.

Contribution

It compares various machine learning models for soft robot kinematics and develops a conformal prediction framework for uncertainty quantification with theoretical guarantees.

Findings

Nonlinear ensemble methods show the best generalization performance.

The conformal prediction framework provides distribution-free, reliable uncertainty intervals.

Limited data can still yield effective kinematic models with uncertainty estimates.

Abstract

Precise kinematic modeling is critical in calibration and controller design for soft robots, yet remains a challenging issue due to their highly nonlinear and complex behaviors. To tackle the issue, numerous data-driven machine learning approaches have been proposed for modeling nonlinear dynamics. However, these models suffer from prediction uncertainty that can negatively affect modeling accuracy, and uncertainty quantification for kinematic modeling in soft robots is underexplored. In this work, using limited simulation and real-world data, we first investigate multiple linear and nonlinear machine learning models commonly used for kinematic modeling of soft robots. The results reveal that nonlinear ensemble methods exhibit the most robust generalization performance. We then develop a conformal kinematic modeling framework for soft robots by utilizing split conformal prediction to quantify predictive position uncertainty, ensuring distribution-free prediction intervals with a theoretical guarantee.