Reference governors: Theoretical Extensions and Practical Applications.

As systems become downsized and operate at the limits of performance, control systems must be designed to ensure that system state and control constraints are satisfied; however, conventional control schemes are often designed without taking constraints into account. Reference governors and the related, more flexible, extended command governors are add-on, constraint enforcement schemes that modify reference signals to conventionally designed, closed-loop systems for the purpose of enforcing output constraints. The focus of this dissertation is on theoretical and methodological extensions of reference and extended command governors, and on their practical applications. Various theoretical results are presented. The first is the development of reduced-order reference and extended command governors, which enables constraint enforcement schemes using simplified models. The second, related development is that of reference governors for decentralized systems that may or may not communicate over a network. The third considers command governors with penalty functions that are used to enforce prioritized sets of constraints, as well as reference governors that are applied to a sequence of prioritized references. The fourth considers the often overlooked case of applying reference governors to linear systems subject to nonlinear constraints; various formulations of constraints are considered, including quadratic constraints and mixed logical-dynamic constraints. The final theoretical development considers using contractive sets to design reference governors for systems with time-varying reference inputs or subject to time-dependent constraints. Numerical simulations are used throughout to illustrate the theoretical advances. The design of reference governor schemes for three systems arising in practical applications is also presented. The first scheme enforces compressor surge constraints for turbocharged gasoline engines, ensuring that the compressor does not surge. The second scheme is designed for an airborne wind energy system that is subject to various flight constraints including constraints on altitude and angle of attack. The third and final scheme is designed for the constrained control of spacecraft attitude, whose discrete-time dynamics evolve on the configuration space SO(3). In the case of the first application, experimental vehicle results are reported that show successful avoidance of surge. For the other two applications, nonlinear model simulation results are reported that show enforcement of system constraints.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113518/1/kalabic_1.pd

“The Vast Experiment”: The New Brunswick Militia’s 1865 Camp of Instruction

In July 1865, almost 1,000 New Brunswick militiamen assembled in Fredericton for a twenty-four day Camp of Instruction. This was the first time peacetime militia training on this scale was ever attempted in British North America. At the time, and since, the camp was praised as a notable achievement. New Brunswick’s lieutenant-governor and provincial commander-in-chief, Arthur Hamilton Gordon, wrote: “The entire success of this experiment is admitted with an unanimity which is remarkable, because rare in this Province.” Although the uniqueness of the camp has been the subject of some interest, it has never been subjected to more in-depth analysis. This article moves beyond generalizations to examine the purpose of the camp and what actually transpired. The Camp of Instruction tells us a great deal about the nature and character of New Brunswick’s militia on the eve of Confederation, and its outcome helps to explain why the province moved towards political union as an answer to the inadequate state of its defences

Popular War: Gauchos and the Challenge to Elite Power in Northern Rio de la Plata in the Revolutionary Period

A Guerra da Independência provocou a mobilização popular no norte da Argentina. Logo que a guerra foi travada nas províncias de Salta e Jujuy, a população rural se alistou em batalhões da milícia desde 1814. Os regulamentos das milícias no Rio da Prata conclamaram na extensão da jurisdição militar (Fuero) seus soldados, e também uma compensação pela sua mobilização para o combate. A mobilização popular no norte de Rio de Prata representou uma ameaça ao poder da elite à medida em que desafiava hierarquias e padrões sociais estabelecidos de longa data desde os tempos coloniais. Ações como a intimidação, a apreensão de gado, e as ocupações de terra foram comumente tomadas pelos gaúchos como atos de justiça social. A elite via-as como atos arrogantes e violentos que visavam cercear seu poder e tirá-los de propriedade e poder.The War for Independence brought about popular mobilization in northern Argentina. As the war was waged in the provinces of Salta and Jujuy, rural population enlisted in militia battalions since 1814. Militia regulations in the Rio de la Plata area called for the extension of military jurisdiction (fuero) to all soldiers as well as for compensation when mobilized for combat. Popular mobilization in Northern Rio de la Plata posed a threat to elite power as it challenged long-held hierarchies and patterns of social deference dating from colonial times. Actions such as intimidation, seizure of livestock, and land occupations were commonly taken by gauchos and regarded by them as acts of social justice. The elite regarded them as arrogant and violent acts aimed at curtailing their power and strip them from their property and power.Fil: Paz, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto de Historia Argentina y Americana ; Argentina. Universidad Nacional de Tres de Febrero; Argentin

Helicopter mathematical models and control law development for handling qualities research

Progress made in joint NASA/Army research concerning rotorcraft flight-dynamics modeling, design methodologies for rotorcraft flight-control laws, and rotorcraft parameter identification is reviewed. Research into these interactive disciplines is needed to develop the analytical tools necessary to conduct flying qualities investigations using both the ground-based and in-flight simulators, and to permit an efficient means of performing flight test evaluation of rotorcraft flying qualities for specification compliance. The need for the research is particularly acute for rotorcraft because of their mathematical complexity, high order dynamic characteristics, and demanding mission requirements. The research in rotorcraft flight-dynamics modeling is pursued along two general directions: generic nonlinear models and nonlinear models for specific rotorcraft. In addition, linear models are generated that extend their utilization from 1-g flight to high-g maneuvers and expand their frequency range of validity for the design analysis of high-gain flight control systems. A variety of methods ranging from classical frequency-domain approaches to modern time-domain control methodology that are used in the design of rotorcraft flight control laws is reviewed. Also reviewed is a study conducted to investigate the design details associated with high-gain, digital flight control systems for combat rotorcraft. Parameter identification techniques developed for rotorcraft applications are reviewed

Reduced Order and Prioritized Reference Governors for Limit Protection in Aircraft Gas Turbine Engines

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140424/1/6.2014-1149.pd

Ties of resistance and cooperation: Aedemon, Lusius Quietus and the Baquates

Gaius' decision to dissolve the protectorate of Mauretania and to depose its client king, Ptolemaeus, led to the outbreak of the Revolt of Aedemon (AD 40). This paper will develop a number of innovative thoughts and hypotheses concerning the extent of this rebellion and its possible impact on the deposition of Ptolemaeus, as well as the role of the Romans in its suppression. The main aim is to explore the connection between this revolt, Trajanus' famous general Lusius Quietus (cos. AD 117?), and the Baquates, an indigenous Mauretanian tribe. I will suggest that Lusius Quietus was descended from a chief of a (semi-)nomadic tribe who supported the Roman cause during the Revolt of Aedemon. Considering the setting and dimension of this revolt, as well as the unrest in Mauretania at the time of Lusius Quietus' execution by Hadrianus, I argue that this tribe can be identified as the Baquates. This reconstruction suggests a long-lasting and particularly positive relationship between this tribe and Rome. It allows for a further reconsideration of the relationship between (semi-)nomadic and Roman/sedentary groups in Roman North Africa, to the detriment of one-sided analytical schemes that stress endemic hostility

Spinning Reserves from Responsive Loads

Report ORNL/TM-2003/1