The implementation of this platform is part of the scientific collaboration between LORIA (D. Martinez, DR-CNRS) and CRAN (M. Boutayeb, PR-UL). The aim is to create a robotic camera system to study the behavior of insects in free flight.
Despite a miniaturized brain, insects are capable of sophisticated sensorimotor processing leading to aeronautical feats and extraordinary sensory capabilities. Insect flight remains mysterious on many points because current technology does not allow the study of insects in completely free flight. This platform aims to fill this gap by proposing the first suspended robot-laboratory operated by cables, capable of following and interacting with an insect free in its movements. The results obtained in 2020 on the tracking of an insect in free flight, published in a leading robotics journal [Acl.Ci.48], constitute a world first that has been widely covered in popular science publications and the general press (Le Monde, Les Échos, Le Point)
The platform, figure 31 and 32, consists of a small nacelle moving in a space of 6m x 4m x 3m. The nacelle is an open cube attached to cables taken from reels. Cameras for locating the insect and measuring flight characteristics are placed there, as well as an infrared illumination system, power supply, and teletransmission. The control law consists of actuating the reels, moving the nacelle, to ensure trajectory tracking. This cable laboratory poses multiple scientific and technological challenges.
Indeed, the dynamic behavior of the cage is described by complex and high-dimensional nonlinear differential equations with six degrees of freedom with very strong constraints on the cable tensions. The control law takes into account the constraints on the cable tension continuously over time, to both keep them taut and avoid their breakage, while ensuring trajectory tracking: that of the insect, unknown in advance. Given the complexity of the system and the limited number of sensors used, the control law must guarantee robustness with respect to uncertainties, transmission delays, and computation times.
The cable laboratory has aroused the interest of several research teams, in particular the Waves Flows Fluctuations team of the Physics Lab at ENS de Lyon. A collaboration has been initiated to study the flight of diurnal butterflies, with a view to a physical modeling of flows and turbulence. On the other hand, a thesis is in progress to apply Artificial Intelligence (AI) techniques to the control and modeling of the cable robot.
