Energy-Based Abstraction for Soft Robotic System Development

Soft robots are designed to convert stored energy into useful work done. Typically, the soft robot designer starts from a type of soft actuation technology at a component level, rather than from a systems engineering level. The characteristics of soft actuation technology may apply constraints on the final system. Bond-graph theory can be used to graphically represent a model of the energy transfer through a system. Top-level abstraction can be in the form of a word bond-graph and bond-graph elements can form a lower component level abstraction. Herein, bond-graph abstraction is applied to different soft actuators and their essential characteristics are identified from an energy-based perspective. Several distinct soft actuation technologies are represented using bond-graph components for each of the key elements: the energy source, the intermediate energy storage, energy dissipation, energy transformation, and the interaction with the environment. By applying this analysis, the soft robot designer is enabled to select the most suitable actuation technology to fulfill their top-level system requirements independently of the actuation domain. A systems engineering approach to develop soft robotic systems leads to more everyday products that impact our everyday lives.