This paper develops a complete framework for coordinated control of multiple unmanned air vehicles (UAVs) that are tasked to execute collision-free maneuvers under strict spatial and temporal constraints in restricted airspace. The framework proposed includes strategies for deconflicted real-time path generation, nonlinear path following, and multiple vehicle coordination. Path following relies on the augmentation of existing autopilots with L1 adaptive output feedback control laws to obtain inner-outer loop control structures with guaranteed performance. Multiple vehicle coordination is achieved by enforcing temporal constraints on the speed profiles of the vehicles along their paths in response to information exchanged over a communication network. Again, L1 adaptive control is used to yield an inner-outer loop structure for vehicle coordination.A rigorous proof of stability and performance bounds of the combined path following and coordination strategies is given. Flight test results obtained at Camp Roberts, CA in 2007 demonstrate the benefits of using L1 adaptive control for path following of a single vehicle. Hardware-in-the-loop simulations for two vehicles are discussed and provide a proof of concept for time-critical coordination of multiple vehicles over communication networks with fixed topologies.

No abstract

No abstract

Autonomous aerial refueling autopilot design is addressed in this paper using a novel L 1 neural-network-based adaptive control approach, which is capable of accommodating trailing-vortex-induced uncertainties and uncertainties in control effectiveness. The main advantage of the new approach is its ability of fast adaptation that leads to uniform transient performance for the system's signals, both inputs and outputs, simultaneously, with guaranteed performance specifications. Simulation results verify the benefit of this new approach. Nomenclature c = wing mean aerodynamic chord g = gravity coefficient h = vertical separation from the tanker, positive down I yy = moment of inertia L p = roll moment derivative due to roll rate L r = roll moment derivative due to yaw rate L = roll moment derivative due to side-slip angle L = roll moment derivative due to aileron deflection l = change of the relative horizontal separation, positive forward M = Mach number M q = pitch moment derivative due to pitch angle M = pitch moment derivative due to angle of attack M e = pitch moment derivative due to elevator deflection m = mass N p = yaw moment derivative due to roll rate N r = yaw moment derivative due to yaw rate N = yaw moment derivative due to side slip N r = yaw moment derivative due to rudder deflection N = yaw moment derivative due to aileron deflection p = roll rate q = pitch rate S = wing reference area V = velocity X q = drag derivative due to pitch rate X V = drag derivative due to velocity X = drag derivative due to angle of attack X T = thrust derivative Y = lateral force derivative due to side-slip angle y = lateral separation relative to the tanker, positive right Z = vertical force derivative due to angle of attack = angle of attack, rad = side-slip angle, rad = flight path angle, rad e = elevator deflection, deg r = rudder deflection, deg T = throttle setting a = aileron deflection, deg = density of air, slugs=ft 3 = pitch angle, rad = roll angle, rad

No abstract