UAV as a Reliable Wingman: A Flight Demonstration

In this brief, we present the results from a flight experiment demonstrating two significant advances in software enabled control: optimization-based control using real-time trajectory generation and logical programming environments for formal analysis of control software. Our demonstration platform consisted of a human-piloted F-15 jet flying together with an autonomous T-33 jet. We describe the behavior of the system in two scenarios. In the first, nominal state communications were present and the autonomous aircraft maintained formation as the human pilot flew maneuvers. In the second, we imposed the loss of high-rate communications and demonstrated an autonomous safe “lost wingman” procedure to increase separation and reacquire contact. The flight demonstration included both a nominal formation flight component and an execution of the lost wingman scenario

A formalism for the composition of concurrent robot behaviors

We introduce tools which help one to compose concurrent, hybrid control programs for a class of distributed robotic systems, assuming a palette of controllers for individual tasks is already constructed. These tools, which combine the backchaining of continuous robot behaviors with Petri nets, expand on successful work in sequential composition of robot behaviors. We apply these ideas to the design and verification of a robotic bucket brigade and to simple, distributed assembly tasks as found in automated factories

Toward the Regulation and Composition of Cyclic Behaviors

Many tasks in robotics and automation require a cyclic exchange of energy between a machine and its environment. Since most environments are under actuated —that is, there are more objects to be manipulated than actuated degrees of freedom with which to manipulate them—the exchange must be punctuated by intermittent repeated contacts. In this paper, we develop the appropriate theoretical setting for framing these problems and propose a general method for regulating coupled cyclic systems. We prove for the first time the local stability of a (slight variant on a) phase regulation strategy that we have been using with empirical success in the lab for more than a decade. We apply these methods to three examples: juggling two balls, two legged synchronized hopping and two legged running—considering for the first time the analogies between juggling and running formally

Money and Goldstone modes

Why is ``worthless'' fiat money generally accepted as payment for goods and services? In equilibrium theory, the value of money is generally not determined: the number of equations is one less than the number of unknowns, so only relative prices are determined. In the language of mathematics, the equations are ``homogeneous of order one''. Using the language of physics, this represents a continuous ``Goldstone'' symmetry. However, the continuous symmetry is often broken by the dynamics of the system, thus fixing the value of the otherwise undetermined variable. In economics, the value of money is a strategic variable which each agent must determine at each transaction by estimating the effect of future interactions with other agents. This idea is illustrated by a simple network model of monopolistic vendors and buyers, with bounded rationality. We submit that dynamical, spontaneous symmetry breaking is the fundamental principle for fixing the value of money. Perhaps the continuous symmetry representing the lack of restoring force is also the fundamental reason for large fluctuations in stock markets.Comment: 7 pages, 3 figure

The Role of Reflexes Versus Central Pattern Generators

Animals execute locomotor behaviors and more with ease. They have evolved these breath-taking abilities over millions of years. Cheetahs can run, dolphins can swim and flies can fly like no artificial technology can. It is often argued that if human technology could mimic nature, then biological-like performance would follow. Unfortunately, the blind copying or mimicking of a part of nature [Ritzmann et al., 2000] does not often lead to the best design for a variety of reasons [Vogel, 1998]. Evolution works on the just good enough principle. Optimal designs are not the necessary end product of evolution. Multiple satisfactory solutions can result in similar performances. Animals do bring to our attention amazing designs, but these designs carry with them the baggage of their history. Moreover, natural design is constrained by factors that may have no relationship to human engineered designs. Animals must be able to grow over time, but still function along the way. Finally, animals are complex and their parts serve multiple functions, not simply the one we happen to examine. In short, in their daunting complexity and integrated function, understanding animal behaviors remains as intractable as their capabilities are tantalizing

Noteworthy records and natural history comments on rare and threatened bird species from Santa Cruz province, Patagonia, Argentina

Santa Cruz province is the second largest province in Argentina, and also the least populated. !is province makes up the southern tip of continental Argentina. Althought it has low population density and is remote from big cities, in the past it received well-deserved attention from researchers. !is was probably due to the presence of many interesting species, among them some threatened, with taxonomic singularities, and/or endemism. !e goal of this work is to update knowledge of the distribution and natural history of 21 species from Santa Cruz, including five new to the province.Fil: Roesler, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Imberti, Santiago. Asociación Ambiente Sur; ArgentinaFil: Casañas, Hernán E.. Asociación Ornitológica del Plata; ArgentinaFil: Hernandez, Pablo M.. Fundación Flora y Fauna Argentina; ArgentinaFil: Klavins, Juan M..Fil: Pagano, Luis G.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; Argentin

Noteworthy records and natural history comments on rare and threatened bird species from Santa Cruz province, Patagonia, Argentina

Santa Cruz province is the second largest province in Argentina, and also the least populated. !is province makes up the southern tip of continental Argentina. Althought it has low population density and is remote from big cities, in the past it received well-deserved attention from researchers. !is was probably due to the presence of many interesting species, among them some threatened, with taxonomic singularities, and/or endemism. !e goal of this work is to update knowledge of the distribution and natural history of 21 species from Santa Cruz, including five new to the province.Facultad de Ciencias Naturales y Muse