This paper presents an approach to vision-based target tracking with a neural network (NN) augmented Kalman filter as the adaptive target state estimator. The vision sensor onboard the follower (tracker) aircraft is a single camera. Real-time image processing implemented in the onboard flight computer is used to derive measurements of relative bearing (azimuth and elevation angles) and the maxi...

We introduce a decentralized attitude control strategy that can dramatically reduce the usage of propellant, by taking full advantage of the physical coupling of the tether. Motivated by a controllability analysis, indicating that both spin-up and relative attitudes are fully controllable by the reaction wheels, we report the first propellant-free underactuated linear and nonlinear control resu...

This paper describes research on 3D formation ight using carrier-di erential GPS sensors. Although absolute position at the centimeter level is generally not possible in real-time, relative position between vehicles within the formation can be obtained at these levels of accuracy using carrier phase di erencing. However, several challenges exist before these measurements can be used in the form...

Flying in formation improves aerodynamic efficiency and consequently leads to an energy savings. One strategy for formation control is to follow the preceding vehicle. Many researchers have shown through simulation results and analysis of specific control laws that this strategy leads to amplification of disturbances as they propagate through the formation. This effect is known as string instab...

This paper describes a fully decentralized nonlinear control law for spinning tethered formation flight, based on exploiting geometric symmetries to reduce the original nonlinear dynamics into simpler stable dynamics. Motivated by oscillation synchronization inbiological systems,weuse contraction theory to prove that a control law stabilizing a single-tethered spacecraft can also stabilize arbi...

In this work we consider the problem of controlling a team of microaerial vehicles moving quickly through a three-dimensional environment while maintaining a tight formation. The formation is specified by a shape matrix that prescribes the relative separations and bearings between the robots. Each robot plans its trajectory independently based on its local information of other robot plans and e...

Copyright q 2012 Zhou Chao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We designed a distributed collision-free formation flight control law in the framework of nonlinear model predictive control. Formation configuratio...

Several NASA and DoD missions are envisioned that will utilize distributed, autonomous clusters of spacecraft. The Air Force Research Laboratory initiated the TechSat 21 mission to demonstrate the key enabling technologies of formation flying and distributed radar. Princeton Satellite Systems developed the Formation Flying Module (FFM) for TechSat 21 to provide autonomous reconfiguration, forma...

The TPF Mission (Terrestrial Planet Finder) is one of the center pieces of the NASA Origins Program. The goal of TPF is to identify terrestrial planets around stars nearby the Solar System. For this purpose, a space-based infrared interferometer with a baseline of approximately 100 m is required. To achieve such a large baseline, a distributed system of five spacecraft flying in formation is an...

In this paper we present a solution for formation flight and formation reconfiguration of unmanned aerial vehicles (UAVs). Based on a virtual leader approach, combined with an extended local potential field, the method is universal applicable by driving the vehicle’s auto pilot. The solution is verified, using a group of UAVs based on a simplified small-scale helicopter, which is simulated in M...