We have gone back to the first principles of physics to reconsider how we can model multi-physical systems related to fluid dynamics in a way which would shift the paradigm to a real composable methodology: a real “LEGO of physics”: a LEGO-piece for the kinetic energy of the fluid, another one for the potential energy of the fluid, another piece to represent viscosity effects in the fluid, another LEGO-piece for the rigid/flexible structure placed in the fluid and so forth.
We performed a careful physical modeling procedure to build a coordinate-free, port-Hamiltonian model of fluid-solid interconnection.
We than tackled new powerful structure preserving methods which have the potential to disrupt how we model physical systems. We introduced a novel method called the Dual field methods, which is able to model interacting fields expressed by PDEs of different domains. A Open source library has been started:
https://phyem.org(s’ouvre dans une nouvelle fenêtre) .
We developed a potential flow wake model to serve a design tool for the development of a new robotic bird. The system components required for this new wind-tunnel setup, such as high-speed cameras, bubble generators and illumination sources have been purchased and used for the last measuring campaign.
A novel 3D flapping-mechanism that allows for better isolation of 3D effects and should help making understanding thrust and lift generation for a theoretically infinite-span wing has been built and used in the wind tunnel campaign.
The 3D flapping-mechanism (see Fig.) used for replicating a wide range of full-wing motion profiles has been a major effort to realise.
Embedded sensing and actuation are essential for realizing new robotic bird prototypes. To realize this, 3D-printing of electrical conductors has been studied by means of models and new experimental methods for characterization (see Fig.). The gained insights are already applied in embedded 3D-printed sensors for measuring beam deformations and for measuring air flow (See Fig.). In combination with a variable stiffness mechanism by means of an axial load, this already allowed for studying new energy-based control laws that are interesting for flapping wings. Such control method was validated on a proof-of-concept mechatronic prototype (see Fig.). Working at such problems, has delivered novel ideas which have been granted with an additional ERC PoC. Such a conceptis currently being acquired by an enterprise. This is related to a methodology which is able via cheap electric measurements, to make a tomographic view of the quality of 3D printing. This is possible by using extrusion polymers which have some electrical conductivities properties and measuring in real time the impedance between the extrusion nozzle and points on the substrate of the print bed. This idea has been patented.
Initial considerations have been made relating to control strategies based on novel machine-learning tools, which can use the data generated by simulations of the fluid-solid interconneection system of interest, to optimise high level performance metrics (e.g. lift generated along a flapping cycle) for some low level control actions (e.g. torque input at joint level). Some initial publications have been published and form a basis for a new line of research which will be continued after the end of the ERC project.
