Stephen Licht

• PhD
• Professor (Assistant) at University of Rhode Island

Increased coastal erosion rates have forced communities to rethink how to manage vulnerable coastlines. In many locations there is a trend towards implementing temporary engineering solutions, such as geotextile sand containers (GSCs) and geo-tubes, to stabilize erosion hot spots and assess the impact of these designs while long-term solutions are...

The objective of this paper is to present the results of on-going field studies to assess the performance of geotextile sand-filled container (GSC) reinforced dunes and to develop probabilistic fragility curves for a range of damage states to these structures. While numerous lab experiments and numerical models have been developed to predict the hy...

The Wire Flyer towed vehicle is a new platform able to collect high-resolution water column sections. The vehicle is motivated by a desire to effectively capture spatial structures at the submesoscale. The vehicle fills a niche that is not achieved by other existing towed and repeat profiling systems. The Wire Flyer profiles up and down along a shi...

In this paper, we investigate the effect of operating near a solid boundary on the forces produced by harmonically oscillating thrust-generating foils. A rolling and pitching foil was towed in a freshwater tank in a series of experiments with varying kinematics. Hydrodynamic forces and torques were measured in the freestream and at varying distance...

In this work we experimentally demonstrate (a) that the holding strength of universal jamming grippers increases as a function of the jamming pressure to greater than three atmospheres, and (b) that jamming grippers can be operated in the deep sea in ambient pressures exceeding one hundred atmospheres, where such high jamming pressures can be readi...

A hybrid depth control approach, which utilizes both active buoyancy control and a bi-directional vertical thruster, is presented for the Shallow Water Lagrangian Imaging Float. The approach is shown to reduce propulsion power and increase tracking accuracy compared to a single actuator system. Results are presented from field trials at Cordell Ban...

The depth controller for a Lagrangian imaging float is detailed, and performance results from simulation and field experiments are used to demonstrate the utility of a model based controller with a complementary control allocation approach. The float is an over actuated system in depth/altitude, which is the only degree of freedom controlled. Verti...

We detail the development of a novel propulsion system for unmanned underwater vehicles (UUV's) inspired by the punting locomotion of the ‘Little Skate’. The hybrid legged, gliding and punting gait is a potential enabling technology for UUV access to complex littoral environments. Design, development and initial trials with the prototype vehicle ar...

This article presents the development of an underwater gripper that utilizes soft robotics technology to delicately manipulate and sample fragile species on the deep reef. Existing solutions for deep sea robotic manipulation have historically been driven by the oil industry, resulting in destructive interactions with undersea life. Soft material ro...

Experimental results are presented for the thrust and lift generation on a NACA0012 airfoil undergoing heave and pitch oscillation near a solid boundary. For ground effect in the steady flow over a lifting surface, lift and drag forces are altered by an enhanced spanwise flow around the tip of the lifting surface, resulting in a strong low pressure...

The development of amphibious robots requires actuation that enables them to crawl as well as swim; sea turtles are excellent examples of amphibious functionality, that can serve as the biomimetic model for the development of amphibious robots. In this paper we have implemented the observed swimming kinematics of Myrtle, a green sea turtle Chelonia...

iRobot was tasked to develop a new payload module and to construct two new vehicles in support of ongoing research at Stevens Institute of Technology. These vehicles were to be equipped with DVL (Doppler Velocity Logs) sensors, enabling more precise navigation while underwater and minimizing the need to surface for frequent GPS fixes. The Ranger pa...

We show experimentally that flapping foil kinematics consisting of a power downstroke and a feathering upstroke together with a properly timed in-line motion, similar to those employed in forelimb propulsion of sea turtles, can produce high thrust and be hydrodynamically as efficient as symmetrically flapping foils. The crucial parameter for such a...

Inspired by the swimming abilities of marine animals, this theses presents "Finnegan the RoboTurtle," an autonomous underwater vehicle (AUV) powered entirely by four flapping foils. Biomimetic actuation is shown to produce dramatic improvements in AUV maneuvering at cruising speeds, while simultaneously allowing for agility at low speeds. Using con...

We demonstrate experimentally that flapping foils within an oncoming stream can efficiently extract energy from the flow, thus offering an attractive, alternative way for energy production. The greatest promise for flapping foils is to use them in unsteady and turbulent flow, where their own unsteady motion can be controlled to maximize energy extr...

Finnegan, the Massachusetts Institute of Technology Biomimetic Flapping Foil Autonomous Underwater Vehicle (BFFAUV), was developed to explore the use of two degree of freedom oscillating foils as the sole means of propulsion and maneuvering for an underwater vehicle. Two pairs of foils with 0.4m span × 0.1m chord are used, with one pair forward and...

The design and construction of a biomimetic flapping foil autonomous underwater vehicle is detailed. The vehicle was designed as a proof of concept for the use of oscillating foils as the sole source of motive power for a cruising and hovering underwater vehicle. Primary vehicle design requirements included scalability and flexibility in terms of t...

The design, construction and testing of a biomimetic flapping foil autonomous underwater vehicle are detailed. The project is a proof of concept for the use of flapping foils as the sole source of propulsion for an underwater vehicle. We intend to use the vehicle in several physical arrangements to compare the swimming performance of different shap...

We propose a biomimetic approach to underwater vehicle propulsion which will extend the operating range of sensor bearing robots into very shallow water. The use of oscillating foils for propulsion, disturbance rejection, bracing against objects, landing, and walking in the presence of currents, wave surge and obstacles is proposed. Discussion will...