Passively-Safe and Robust Multi-Agent Optimal Control with Application to Distributed Space Systems

This paper presents a novel methodology to enforce motion safety guarantees even in the event of a sudden loss of control capabilities by any agent within a multi-agent system. This passive safety methodology permits the replacement of point-evaluated constraints on the trajectory following a contingency with a single function of the integration constants of the equations of motion at contingency instants. The effects of uncertainties on the trajectory are compensated for through the method of variation of parameters. This permits a reduction in the number of required constraints by one polynomial degree in the number of discrete time samples, and allows computationally efficient enforcement of passive safety within a multi-agent optimal control problem, solvable using direct methods. The main application is distributed space systems employing miniaturized low size-weight-and-power and commercial-off-the-shelf technology, which reduce mission financial costs at the expense of reliability. Experimental results for the upcoming Virtual Super-resolution Optics with Reconfigurable Swarms (VISORS) mission, as well as complementary formation-flying test cases in eccentric orbits, demonstrate the advantages of the proposed methodology in achieving fault-tolerant safety guarantees, as well as computational efficiency.