GPS-free Collaborative Elliptical Circumnavigation Control for Multiple Non-holonomic Vehicles

This paper investigates a novel GPS-free collaborative elliptical circumnavigation control for multiple non-holonomic vehicles, where two realistic issues—achieving a higher efficiency observation and saving the energy expenditures during cooperation are involved. By defining a novel coordinated error relative to neighboring arc length, under the premise of accessible global position, a cooperative elliptical enclosing control strategy is derived for multiple vehicles connected by a digraph to enable formation behaviors with a uniform forward speed. To surmount the reliance on global position data in hostile surroundings where GPS is being attacked or disrupted, by resorting to a distance-based relative position observer, a new GPS-free cooperative elliptical circling controller is formulated to force all vehicles to collaboratively evolve along the prescribed ellipse. The special innovation includes two aspects, one is that by specifying the adjacent arc length instead of separation angles appearing in existing vehicle coordination, energy consumption can be reduced by approximately 7.6% during cooperative periodic enclosing process, another is that the dependency on global position can be removed by resorting to a relative position estimator utilizing distance-only data. It is inferred from Lyapunov stability that all signals are demonstrated to be convergent. Eventually, both simulation and experimental results substantiate the utility of suggested avenue.