This paper presents a multi-AUV state-estimator that can determine the 3D position of a tagged fish. In addition to angle measurements, the state-estimator also incorporates distance and depth measurements. These additional sensor measurements allow for greater accuracy in the position estimates. A newly developed motion model that better accounts for multiple hypotheses of the motion of a tagged fish is used to increase the robustness of the state-estimator. A series of multi-AUV shark tracks were conducted at Santa Catalina Island, California over the span of four days to demonstrate the ability of the state-estimator to determine the 3D position of a tagged leopard shark. Additional experiments in which the AUVs tracked a tagged boat of known location were conducted to quantify the performance of the presented state-estimator. Experimental results demonstrate a three-fold decrease in mean state-estimation error compared to previous works.

We consider cooperative control of robots involving two different testbed systems in remote locations in different time zones, with communication on the internet. The goal is to have all robots properly follow a leader defined on one of the testbeds, while maintaining non-overlapping positions within each swarm and between swarms, assuming they are superimposed in the same virtual space. A dual-testbed design is developed involving real robots and remote network communication, performing a cooperative swarming algorithm based on a modified Morse Potential. Extensive experimental results were obtained with real internet communication and virtual testbeds running in each lab. The communication protocol was designed to minimize loss of packets, and average transfer delays are within tolerance limits for practical applications. We ran several experiments, with intentional packet loss, that illustrate the degradation of the results in the case of modest and severe packet loss. The novelty of this work is its experimental aspect involving long range network communication across a large distance via the internet. The work raises a series of interesting theoretical problems.