Control theory tools for Optimal Design of piezoelectric Energy Harvesters devoted to birds Tracking devices – CODE-Track

CODE-Track focuses on the design of piezoelectric energy harvesting structures devoted to replace solar panel in tracking devices and on their fabrication. The scientific originality lies in the exploitation and extension of topology optimization techniques to design structures able to maximize output power while minimizing their volume and mass. The challenges are the integration of piezoelectric phenomena in the optimization, its extension into 3 dimensions in order to obtain optimal 3D shaped structures, the integration of constrains related to the targetted birds flapping wings such as low frequency, and the fabrication of the resulting 3D designed piezoelectric structures. To fabricate the issued 3D designed structures, the project proposes to combine 3D fabrication of the passive, i.e. non-piezoelectric, elements with 2D fabrication of the piezoelectric elements. Finally, the last step of the project deals with the experimental characterization and the proof of concept regarding the optimally designed energy harvesters.

- Development of systematic methods to design piezoelectric structures devoted to harvest energies from in-plane vibration and from spatial vibration.
- Proposition of MATLAB code on topology optimization for the design of piezoelectric energy harvesters and actuators, the code being published at Structural and Multidisciplinary Optimization journal.
- Fabrication of several prototypes of optimally designed 3D energy harvesters.
- Experimentation and concept validation regarding energy harvesters working with in-plane vibration and with spatial vibration.
- Creation of a new partnership with the International Centre of Insect Physiology and Ecology (ICIPE, Nairobi) for common work on tracking swarm of insects, in particular grasshoppers.
- Submission of an ANR project with mechanics research group, Artificial Intelligency research group, textile modeling research group, and with the AMAROB Technologies company in Besançon. The project extends the piezoelectric topology optimization from CODE-Track to design an autonomous and eco-friendly diagnosis device able to simultaneously measure pulse, tension and skin/muscle stiffness around the human arm.

- Exploitation and extension of the developped piezoelectric topology optimization to design robotic hand having actuation and sensing capabilities while manipulating deformable objects within Industry of Future context.
- Exploitation and extension of the developped piezoelectric topology optimization to design an autonomous and eco-friendly diagnosis device based on piezoelectric PVDF material and biocompatible and ecological Lyocell textile material.

The results of CODE-Track led to 7 international journals and 6 international conferences in the following fields: mechatronics, robotics, optimization, microsystems, micro-bio robotics, and instrumentation. 2 national communications have also accompanied these publications. In addition to these, the project has also permitted the co-organization of a special issue on « piezoelectric nanogenerators for autonomous sensors » at the Micromachines journal in collaboration with 2 researchers from Georgia Institute of Technology and from Xidian University. Moreover, thanks to the invitation of CNRS, the project has been presented in a vulgarized article in a chapter of the book Ingénierie Verte edited by INSIS-CNRS and published in 2019.
Finally, several vulgarization and transfers have been produced: seminars in foreigner Universities, demonstrator during the yearly event fête de la science at ENIT in Tarbes, creation of 2 courses on « energy harvesting » and on « topology optimization for active structures » within the international master on control for green mechatronics of the Université Bourgogne Franche-Comté and which I head until my departure towards ENIT in 2019.

This project deals with the exploration of the possibility to use control theory tools for the design of vibrational piezoelectric energy harvesters (vPEH) devoted to supply tracking devices in migratory birds. The proposed explored techniques, radically different and scientifically novel relative to existing design methods of vPEH, will provide four major advantages: i) giving methodological designs, ii) pushing the actual limitation on power density, iii) introducing robustness for the harvested energy over a frequency variation of the ambient vibrations, iv) and permitting the substantial increase of their autonomy. The impact of the resulting vPEH to birds tracking are evident: volume and weight radically small allowing to equip more species of birds while than the actual possibility, devices autonomy extremely high (calculated for the bird entire life), and safety and harmlessness for the equipped animal thanks to the reduced sizes and weights.