Optimized navigation control of an underwater fish-like robot applied to monitoring and inspection.

We propose a research program to study the modeling and control of an underwater vehicle equipped with a bio- inspired fin-based propulsion system. The propulsion system of the vessel consists of a single undulating fin running along the length of the robot, which controls both forward motion and directional maneuvers. The objectives of the program include (i) developing mathematical model of the system; (ii) establish a control model relating fin kinematics to the motion of the vessel; (iii) studying the performance of the vessel in both laboratory and field experiments. To accomplish these objectives PI prof. Colorado and a graduate student from Pontificia Universidad Javeriana will work in close collaboration with Dr. Curet from Florida Atlantic University (FAU). The proposed work will fund three years of collaboration with three summer visits to FAU where the experiments will be conducted. Colombia is one of the strongest countries in South America for continental aquaculture fish-farming [1]. However, in spite of having access to both Pacific and Atlantic oceans, Colombia’s marine-based aquaculture is still on early stages but with tremendous potential and opportunities to boost the aquaculture industry, specially, in the Caribbean offshores. Several challenges are presented in terms of keeping the healthy growth of fishes and other species by properly monitoring and conserving the natural habitats [2]. Coral reefs are extremely fragile ecosystems key for the proper development of ocean species. Understanding the effects of fishing on coral reef ecosystems require the involvement of several disciplines working on novel methods and technologies for ensuring a sustainable future. In this regard, Colombia is now seriously engaged for tackling the challenge of marine conservation of coral reefs to preserve natural species [3]. The exploration of littoral and reef areas requires highly maneuverable underwater vehicles able to navigate and hover in cluttered spaces in presence of intense water motion. In this collaboration, we propose to incorporate the expertise and knowledge of working in high-performance closed-loop control methods applied to bio-inspired robots [6-14], with the aim of enabling the Knifefish-like robot to operate autonomously underwater. The underwater robot, c.f. Figure 1, was developed by Curet et. al., [4, 5] at the Department of Ocean and Mechanical Engineering in Florida Atlantic University. The robot’s morphology is biologically inspired by the knifefish; a tropical fish with great dexterity able to maneuver in confined spaces. Our primarily goal is to develop a novel navigation controller to enable the knifebot of high maneuverability in underwater monitoring labors. Navigating within coral reef confined habitats is an extremely challenging task that demands a system capable of highly precise movements. To achieve this, comprehensive nonlinear equations of motion for the Knifefish-like robot need to be derived, including the experimental characterization and dynamics modeling of several kinematics and physical effects that govern the primarily motion principles of this robotics platform, such as: the surge, sway forces, the yaw moments, drag forces, among other highly nonlinear effects. Furthermore, the control system requires the parametric characterization of the aforementioned effects in order to properly regulate the robot, rejecting external disturbances caused by underwater currents and achieving high precise tracking of the desired navigation trajectory. Both issues (dynamics modeling and closed-loop control) present several challenges in terms of real- time computational modeling, onboard control electronics setup, mechanical joint actuation, and accurate sensing feedback.