Design of a locomotive system for the exploration of rugged and deformable terrain

Abstract

The importance of natural environments with rugged deformable terrain (marshes, mangroves, rainforests, coastlines) from biodiversity, carbon capture, and coastal protection to economic livelihood is significant. However, the current systems available for robots to explore those ecosystems are either large, expensive and intrusive, not application focused or consist of custom components that are difficult to integrate with existing robotic mechanisms. This thesis proposes a novel soft adaptable wheel suited for such ecosystems. The mechanism operates as a fluidic elastomer actuator constructed with Dragon Skin 30 able to change its form depending on the task at hand. Various designs were simulated in MuJoCo to test its ability to overcome rigid obstacles and terrain forms (from ramps, steps, smooth undulating terrain and terraced undulating terrain). The design's structural feasibility was then tested and further improved using Ansys with the final result having a loading capacity of 1.25N (at 0kPa) and a maximum blocked force of 1.98N (at 35kPa). Finally, the wheel was tested at 3 distinct operating configurations (neutral, partial and fully inflated) in 4 types of deformable terrain (non-compressible dry, compressible dry, non-compressible sticky, compressible sticky) using EDEM Altair. This evaluated its performance and validated the need for different forms according to the rheological properties of the terrain. The design proposed in this paper is intended to be more application-focused, with its simplicity facilitating integration into robotic systems, using off-the-shelf components, and ultimately reducing the time required to be used in environmental applications.