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Task-Driven Multi-Formation Control For Coordinated Uav/Ugv Isr Missions, Herbert G. Tanner Oct 2006

Task-Driven Multi-Formation Control For Coordinated Uav/Ugv Isr Missions, Herbert G. Tanner

Mechanical Engineering Faculty Publications

The report describes the development of a theoretical framework for coordination and control of combined teams of UAVs and UGVs for coordinated ISR missions. We consider the mission as a composition of an ordered sequence of subtasks, each to be performed by a different team. We design continuous cooperative controllers that enable each team to perform a given subtask and we develop a discrete strategy for interleaving the action of teams on different subtasks. The overall multi-agent coordination architecture is captured by a hybrid automaton, stability is studied using Lyapunov tools, and performance is evaluated through numerical simulations.


Thermodynamically Consistent Relations Involving Plasticity, Internal Energy And Thermal Effects, Howard Schreyer, Paul Maudlin Mar 2006

Thermodynamically Consistent Relations Involving Plasticity, Internal Energy And Thermal Effects, Howard Schreyer, Paul Maudlin

Mechanical Engineering Faculty Publications

Experimental data associated with plastic deformations indicate that the temperature is less than that predicted from dissipation based on plastic work. To obtain reasonable correlation between theoretical and experimental results, the plastic work is often multiplied by a constant β. This paper provides an alternative thermodynamic framework in which it is proposed that there is an additional internal energy associated with dislocation pile-up or increase in dislocation density. The form of this internal energy follows from experimental data that relates flow stress to dislocation density and to equivalent plastic strain. The result is that β is not a constant but ...


Increasing The Accuracy Of Cooperative Localization By Controlling The Sensor Graph, Deepti Kumar, Herbert G. Tanner Mar 2006

Increasing The Accuracy Of Cooperative Localization By Controlling The Sensor Graph, Deepti Kumar, Herbert G. Tanner

Mechanical Engineering Faculty Publications

We characterize the accuracy of a cooperative localization algorithm based on Kalman Filtering, as expressed by the trace of the covariance matrix, in terms of the algebraic graph theoretic properties of the sensing graph. In particular, we discover a weighted Laplacian in the expression that yields the constant, steady state value of the covariance matrix. We show how one can reduce the localization uncertainty by manipulating the eigenvalues of the weighted Laplacian. We thus provide insight to recent optimization results which indicate that increased connectivity implies higher accuracy and we offer an analysis method that could lead to more efficient ...