Time-optimal path planning in dynamic flows using level set equations: realistic applications

Tapovan Lolla, Patrick J. Haley, Pierre F. J. Lermusiaux
2014 Ocean Dynamics  
The level set methodology for time-optimal path planning is employed to predict collision-free and fastest time trajectories for swarms of underwater vehicles deployed in the Philippine Archipelago region. To simulate the multiscale ocean flows in this complex region, a data-assimilative primitive-equation ocean modeling system is employed with telescoping domains that are interconnected by implicit two-way nesting. These data-driven multiresolution simulations provide a realistic flow
more » ... nt, including variable large-scale currents, strong jets, eddies, wind-driven currents and tides. The properties and capabilities of the rigorous level set methodology are illustrated and assessed quantitatively for several vehicle types and mission scenarios. Feasibility studies of all-to-all broadcast missions, leading to minimal time transmission between source and receiver locations, are performed using a large number of vehicles. The results with gliders and faster propelled vehicles are compared. Reachability studies, i.e. determining the boundaries of regions that can be reached by vehicles for exploratory missions, are then exemplified and analyzed. Finally, the methodology is used to 2 T. Lolla et al. large-scale open ocean and atmospheric forcing, ener-21 getic mesoscale currents and eddies, and strong tides 22 and internal waves both in narrow straits and at steep 23 shelf breaks. Such conditions provide challenging envi-24 ronments for the planning of autonomous underwater 25 missions. 26 In what follows, §2 outlines the ocean modeling sys-27 tem employed for the region and the corresponding mul-28 tiscale ocean flows and their evolution, highlighting key 29 characteristics for the autonomous vehicles. In §3.1, we 30 compute, compare and analyze the time-optimal paths 31 of 1600 gliders and propelled vehicles performing all-32 to-all broadcast missions through the Archipelago. The 33 effects of the multiscale flows and vehicle speeds on the 34 trajectories and on the overall information transmission 35 rates are discussed and synthesized. In §3.2, we consider 36 the deployment of vehicles and complete reachability 37 analyses for the Sulu Sea, i.e. we predict the portions 38 of the Sulu Sea that can be reached and explored within 39 a certain time for a set of deployment locations. In §3.3, 40 we consider the recovery of vehicles and fastest inter-41 ception with other platforms. Specifically, we predict 42 the trajectories for autonomous vehicles that lead to 43 the fastest time pick-up by either underway or fixed 44 platforms. Conclusions are provided in §4. 45 2 Multiresolution Ocean Modeling System and 46 Multiscale Ocean Flow Field 47 Multiresolution Ocean Modeling and Data-assimilative 48 Simulations. To predict the multiscale ocean flow dy-49 namics in the Philippine Archipelago region, we employ 50 the MIT Multidisciplinary Simulation, Estimation, and 51 Assimilation System (MSEAS) (Haley and Lermusiaux, 52 2010; MSEAS Group, 2010). The MSEAS software is 53 used for fundamental research and for realistic tidal-54 to-mesoscale simulations and predictions in varied re-55
doi:10.1007/s10236-014-0760-3 fatcat:ovfwo2wxkba55cljoi2c2yw24y