Locomotion and transitions of an amphibious system: Biologic to Robotic
Abstract
This project has two main objectives: (1) to refine our knowledge of the novel propulsion mechanisms of the California sea lion (Zalophus californianus) and extend it to high demand underwater environments; and (2) to develop a biological, i.e. morphologic and kinematic, understanding or sea lion locomotion on land. The proposed work will build on, and extend, fundamental studies of the California sea lions swimming mechanism and thrust production capabilities. This marine mammal displays morphological and behavioral characteristicsspeed, agility, and flexibilitythat allow it to operate in flow conditions that conform to projected naval operations (see Fig. 1). Additionally, it will extend preliminary work on the sea lions ability to operate on land. See lions are naturally amphibious, spending significant time in the water and on land throughout their life cycles. They are some unique bio-morphologicaladaptations that allow them to successfully exploit both environments.The proposed work will build on and extend fundamental studies of the California sea lions swimming mechanism and thrust production capabilities. This marine mammal displays morphological and behavioral characteristicsspeed, agility, and flexibilitythat allow it to operate in flow conditions that conform to projected naval operations. Additionally, it will extend preliminary work on the sea lions ability to operate on land. See lions are naturally amphibious, spending significant time in the water and on land throughout their life cycles.They are some unique bio-morphological adaptations that allow them to successfully exploit both environments. This study will use the digital catalog of sea lion kinematics to develop a platform that can freely swim with optimized performance. This includes a shape changing spine (sea lions are highly flexible and exploit this flexibility to increase their efficiency and maneuverability) and head movement. The propulsive forces will be created by a compliant set of foreflippers that create thrust through an optimized power stroke that is based on previous results from a broad sample of kinematic data. This work will include both modeling and simulation as well as physical platform development.This project is a natural, innovative extension of work on unsteady propulsion that has been carried out over the last decade. However, unlike previous results, which indicate that efficient underwater thrust production is at the cost of maneuverabxibility, the sea loin offers a potential paradigm wherein efficient, effective propulsion does not have to be dominated by heaving and pitching fins at a regular oscillatory frequency. Thus, it has the specific potential for creating efficient, robust underwater propulsion that can operate over a range of flow conditions and has the potential to move from the surf to the shore and be integrated into hybrid human/drone AI enabled teams, an expressed mission of the Office of Naval Research (ONR).This project will have a strong scientific contribution, both in the physics that will be explored and the methods that will be developed. The methods include extension of markerless tracking and laser-free flow measurements that can be used to study other large, protected biological systems that are not amenable to laboratory testing. The physics we will explore, the efficient, pulsatile swimming of the sea lion that incorporates that reactions of the fins and flexing body, will explore a new paradigm of high performance biologically inspired locomotion in both water and on land. Finally, we will provide insight into the complex connection of fin, body forces and their contro
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 02, 2021
- Source ID
- N000142112133
Entities
People
- Megan C. Leftwich
Organizations
- George Washington University
- Office of Naval Research
- United States Navy