String Stable Heterogeneous Aircraft in a Windy Environment

Abstract

This research develops and analyzes an approach to solve the continuous monitoring problem. The analysis focuses on the string stability of a system of airspeed heterogeneous nonlinear aircraft that are controlled to overfly an endpoint at specified time intervals. The system is modeled as a cascaded set of subsystems where the position of each subsystem, an individual aircraft, is based off the estimated overfly time of the preceding vehicle. The model also includes the effects of steady-state wind and turbulence. The system is made to be string stable by nondimensionalizing a portion of the dynamics, selecting variable command limits, and solving for exponentially stable controller gains. The simulation results confirm the stability guarantees of the theoretical analysis and show that a randomized group of 20 airspeed heterogeneous aircraft experiencing realistic wind and turbulence results in an estimated arrival time error that converges toward a relatively small steady-state range.