Self-Reconfigurable Soft-Rigid Mobile Agent with Variable Stiffness and Adaptive Morphology

TL;DR

This paper introduces a hybrid mobile robot with controllable stiffness and shape-shifting abilities, enabling adaptive motion modes and conformability, validated through simulations and experiments.

Contribution

It presents a novel design of a soft-rigid hybrid robot with variable stiffness and shape, along with a unified kinematic model and optimized control strategy.

Findings

Successful simulation and experimental validation

Effective shape adaptation and motion control

Open-source simulation code available

Abstract

In this paper, we propose a novel design of a hybrid mobile robot with controllable stiffness and deformable shape. Compared to conventional mobile agents, our system can switch between rigid and compliant phases by solidifying or melting Field's metal in its structure and, thus, alter its shape through the motion of its active components. In the soft state, the robot's main body can bend into circular arcs, which enables it to conform to surrounding curved objects. This variable geometry of the robot creates new motion modes which cannot be described by standard (i.e., fixed geometry) models. To this end, we develop a unified mathematical model that captures the differential kinematics of both rigid and soft states. An optimised control strategy is further proposed to select the most appropriate phase states and motion modes needed to reach a target pose-shape configuration. The performance of our new method is validated with numerical simulations and experiments conducted on a prototype system. The simulation source code is available at https://github.com/Louashka/2sr-agent-simulation.git}{GitHub repository.