Identification of the inertia matrix of a rotating body based on errors-in-variables models

This paper proposes a procedure for identifying the inertia matrix of a rotating body. The procedure based on Euler's equation governing rotational motion assumes errors-in-variables models in which all measurements, torque as well as angular velocities, are corrupted by noises. In order for consistent estimation, we introduce an extended linear regression model by augmenting the regressors with constants and the parameters with noise-contributed terms. A transformation, based on low-pass filtering, of the extended model cancels out angular acceleration terms in the regressors. Applying the method of least correlation to the model identifies the elements of the inertia matrix. Analysis shows that the estimates converge to the true parameters as the number of samples increases to infinity. Monte Carlo simulations demonstrate the performance of the algorithm and support the analytical consistency. Copyright © 2009 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65054/1/1112_ftp.pd

Revisión de sistemas de control en red como base para sistemas satelitales de pequeña escala

el presente artículo parte de la premisa complementaria entre sistemas satelitales de gran escala y sistemas en red de pequeña escala que puedan suplir los mismos servicios, por lo tanto, se presentan diferentes enfoques de trabajos desarrollados en torno a los aportes de sis- temas de control en red, como fundamento al desarrollo de nuevas tecnologías en la operación de sistemas satelitales y de servicios aeroespaciales, los cuales se han convertido en un desafío permanente para diferentes disciplinas y países en vía de desarrollo alrededor del mundo. En este sentido, se realizó una revisión descriptiva organizada mediante tópicos y descriptores para la búsqueda de factores de diseño en relación con los sistemas de operación y control que han sido fuente de trabajo, tanto para la con guración de constelaciones como de clúster satelitales; logrando con esto identi car las tendencias y aportes que en materia de sistemas multiagente se han desarrollado, así como las pautas necesarias para la formulación de soluciones a las necesidades de coordinación de sistemas de bajo costo, que sean capaces de brindar alternativas sostenibles para países como Colombia frente a la democratización del espacio. Con esta revisión se obtienen como resultados diferentes lineamientos para la definición de requerimientos, la descripción de arquitecturas y modelos de referencia, así como algunos factores de uso en tecnologías comparadas, que en términos prácticos brindan las herramientas para la generación de alternativas de diseño de misión en aplicaciones de seguridad crítica y defensa, que pueden ser extendidas en enfoques de sistemas satelitales multiagente

Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations

On-orbit servicing (OOS) of space systems provides immense benefits by extending their lifetime, by reducing overall cost of space operations, and by adding flexibility to space missions. Refueling is an important aspect of OOS operations. The problem of determining the optimal strategy of refueling multiple satellites in a constellation, by expending minimum fuel during the orbital transfers, is challenging, and requires the solution of a large-scale optimization problem. The conventional notion about a refueling mission is to have a service vehicle visit all fuel-deficient satellites one by one and deliver fuel to them. A recently emerged concept, known as the peer-to-peer (P2P) strategy, is a distributed method of replenishing satellites with fuel. P2P strategy is an integral part of a mixed refueling strategy, in which a service vehicle delivers fuel to part (perhaps half) of the satellites in the constellation, and these satellites, in turn, engage in P2P maneuvers with the remaining satellites. During a P2P maneuver between a fuel-sufficient and a fuel-deficient satellite, one of them performs an orbital transfer to rendezvous with the other, exchanges fuel, and then returns back to its original orbital position. In terms of fuel expended during the refueling process, the mixed strategy outperforms the single service vehicle strategy, particularly with increasing number of satellites in the constellation. This dissertation looks at the problem of P2P refueling problem and proposes new extensions like the Cooperative P2P and Egalitarian P2P strategies. It presents an overview of the methodologies developed to determine the optimal set of orbital transfers required for cooperative and non-cooperative P2P refueling strategies. Results demonstrate that the proposed strategies help in reducing fuel expenditure during the refueling process.Ph.D.Committee Chair: Panagiotis Tsiotras; Committee Member: Eric Feron; Committee Member: Joseph Saleh; Committee Member: Ryan Russell; Committee Member: William Coo