Distributed Parameter Modeling and Boundary Control of an Octopus Tentacle-Inspired Soft Robot

Inspired by soft organisms in nature, engineers have been exploring the mechanical design of soft robots manufactured by compliant materials. However, some limitations still exist in the modeling and control of soft robots. This article studies a cable-driven soft robot with shape and bending motion inspired by an octopus tentacle. By the extended Hamilton's principle, the dynamic equation of the soft robot is derived in a distributed parameter system (DPS), which is governed by a partial differential equation. The boundary control strategy for the soft robot is developed via Lyapunov-based design to achieve distributed bending angle tracking. The stability analysis of the closed-loop system is presented using LaSalle's invariance principle to show that the total energies in the system, and hence, the distributed states of the system, remain bounded and tend asymptotically to the desired values. Some simulation results are applied to demonstrate the applicability and effectiveness of the employed model and control. This study will promote the application of DPS theory in soft robots.