Periodic Reporting for period 4 - PORTWINGS (Decoding the Nature of Flapping Flight by port-Hamiltonian System Theory)
Periodo di rendicontazione: 2023-04-01 al 2024-03-31
What are the secrets of bird flights? After 500 years from the first studies of Leonardo da Vinci, we understand much better the principles, but we are far from having decoded the various details of the interaction between the wings motion and the fluid around it which allows birds to fly. In PortWings we had the ambition to change this by using novel modeling methods based on Port Hamiltonian System theory to deeply understand the multi-physics described by coupled Partial Differential Equations (PDEs) involved and then build new mechatronic prototypes which use the developed theory together with innovative engineering techniques in design and materials. Managing in doing that, the knowledge gained in the process will have a multitude of applications in energy, biology and all those filelds where multi-physics and control of complex dynamics plays a role.
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(si apre in una nuova finestra) .
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.
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(si apre in una nuova finestra) .
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.
Our main achievements in the theoretical side that are beyond the state of the art include the mathematical modeling of fluid-dynamic systems using the geometric port-Hamiltonian theory relying on exterior calculus which is in contrast to the widely used vector calculus formulation. Such exterior calculus formulation has provided great understanding of the underlying physical principles of the system without being contaminated by certain coordinate representations.
Thanks to the multi-physical nature of the port-Hamiltonian theory, such knowledge displayed in the geometric formulation can be easily transfered to other physical domains including electromagnetism and quantum mechanics, which is currently being investigated by the project's PI and some collaborators within another project. The PI expects that such methodologies will have a profound effect on how we will study physics in the future, how we will model it, and how we will simulate physical processes. The PI intends to continue this endeavour applying for a ERC synergy grant together with an expert theoretical physicist and mathematician, Prof. Frederic Schuller, who has also been inspired by such novel methodologies.
We have achieved unprecedented methods to systematically interconnect any physical systems described by either ODEs or PDEs: we are able to interconnect fluid-dynamical port-Hamiltonian models to rigid and flexible mechanism and have conceptual ideas in how to simulate them with a new structure-preserving discretisation methodology. The fundamental results which we have achieved in nonlinear elasticity have been published on high impact factors journals and already been noticed by top groups in the field.
We concluded the project with a unique wind tunnel campaign using the purchased helium-soap bubble setup combined with the mechanical 2D and 3D flapping setups to generate a large amount of data.
Such measurement data is still under analysis and will allow us to estimate the pressure distribution over the wing. Also insight is expected in the aerodynamic loads.
The generated data will be shared with the public.
Overall the PI considers the project a great success especially in the fundamental contributions which will have a fundamental effect in future modelling tools, insights and very likely also academic education.
A professional video summarising the project and its result which can be found here: https://youtu.be/PXh0AIWxJoo?si=YaZdxf4n1rNFOMlL(si apre in una nuova finestra)
Thanks to the multi-physical nature of the port-Hamiltonian theory, such knowledge displayed in the geometric formulation can be easily transfered to other physical domains including electromagnetism and quantum mechanics, which is currently being investigated by the project's PI and some collaborators within another project. The PI expects that such methodologies will have a profound effect on how we will study physics in the future, how we will model it, and how we will simulate physical processes. The PI intends to continue this endeavour applying for a ERC synergy grant together with an expert theoretical physicist and mathematician, Prof. Frederic Schuller, who has also been inspired by such novel methodologies.
We have achieved unprecedented methods to systematically interconnect any physical systems described by either ODEs or PDEs: we are able to interconnect fluid-dynamical port-Hamiltonian models to rigid and flexible mechanism and have conceptual ideas in how to simulate them with a new structure-preserving discretisation methodology. The fundamental results which we have achieved in nonlinear elasticity have been published on high impact factors journals and already been noticed by top groups in the field.
We concluded the project with a unique wind tunnel campaign using the purchased helium-soap bubble setup combined with the mechanical 2D and 3D flapping setups to generate a large amount of data.
Such measurement data is still under analysis and will allow us to estimate the pressure distribution over the wing. Also insight is expected in the aerodynamic loads.
The generated data will be shared with the public.
Overall the PI considers the project a great success especially in the fundamental contributions which will have a fundamental effect in future modelling tools, insights and very likely also academic education.
A professional video summarising the project and its result which can be found here: https://youtu.be/PXh0AIWxJoo?si=YaZdxf4n1rNFOMlL(si apre in una nuova finestra)