LQR distributed cooperative control of a formation of low-speed experimental UAVs

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-The paper presents a cooperative scheme for controlling arbitrary formations of low speed experimental UAVs based on a distributed LQR design methodology. Each UAV acts as an independent agent in the formation and its dynamics are described by a 6-DOF (degrees of freedom) nonlinear model. This is linearized for control design purposes around an operating point corresponding to straight flight conditions and simulated only for longitudinal motion. It is shown that the proposed controller stabilizes the overall formation and can control effectively the nonlinear multi-agent system. Also, it is shown via numerous simulations that the system provides reference tracking and that is robust to environmental disturbances such as nonuniform wind gusts acting on a formation of four UAVs and to the loss of communication between two neighbouring UAVs. Permanent repository link

Distributed LQR Methods for Networks of Non-Identical Plants

“…The need for forming networks of systems in many cases arises from the fact that some problems might not be resolved by individual systems. Military applications, transport networks and supply chains are such paradigms which indicate that difficult tasks may be accomplished cooperatively [1]- [3]. In other cases, the topology of the network may be imposed by physical links such as in power systems where the agents take the role of power generators and the interconnections are represented by power transmission lines [4], [5].…”

Cooperative Distributed LQR Control for Longitudinal Flight of a Formation of Non-Identical Low-Speed Experimental UAV's

“…Multi-vehicle systems have attracted a lot of attention of the control community in recent years due to their wide range of applications, such as area mapping and monitoring [1], formation control [2], [3], vehicle platoons [4], etc. Such schemes are often referred to as multi-agent systems with each agent being represented by a dynamical system and having the ability to communicate with other counterparts within the network.…”

“…In [3] the distributed LQR method introduced in [6] is used to solve the formation control problem of a network of identical UAV's. In this work, we extend this top-down approach to networks formed of non-identical UAV's.…”

“…In this work, we extend this top-down approach to networks formed of non-identical UAV's. The non-linear model of the low-speed experimental UAV used in [3] known as X-RAE1 is also utilized in this paper for simulations purposes. The formation flying is considered to be composed of dynamically decoupled X-RAE1 which differ in their masses and their symmetry about the xz plane.…”

“…To our knowledge no direct extension method of distributed LQR control with non-identical dynamics based on the methodology of [6] and [7] has been reported in the literature. The distributed LQR method proposed in [3] to solve the formation control of four identical UAV's is appropriately adjusted and applied to the formation of the non-identical UAV's. Note that, in contrast to recent methods in the area, our approach does not rely on a two-step design procedure in which high-level formation control based exclusively on kinematics is superimposed on a low-level flight control scheme of each individual UAV in the formation, based on a fully dynamic model.…”