Application of MPC and sliding mode control to IFAC benchmark models

The comparison of Model Predictive Control (MPC) and Sliding Mode Control (SMC) are presented in this paper. This paper investigates the performance of each controller as the navigation system for IFAC benchmark ship models (cargo vessel and oil tanker). In this investigation the navigation system regulates the heading angle of the two types of marine vessel with reference to a desired heading trajectory. In this investigation, the result obtained from MPC is compared with a well-established control methodology, namely Sliding Mode control theory. Wave disturbances and actuator limits are implemented to provide a more realistic evaluation and comparison for the proposed control structure

New interpretation of variational principles for gauge theories. I. Cyclic coordinate alternative to ADM split

I show how there is an ambiguity in how one treats auxiliary variables in gauge theories including general relativity cast as 3 + 1 geometrodynamics. Auxiliary variables may be treated pre-variationally as multiplier coordinates or as the velocities corresponding to cyclic coordinates. The latter treatment works through the physical meaninglessness of auxiliary variables' values applying also to the end points (or end spatial hypersurfaces) of the variation, so that these are free rather than fixed. [This is also known as variation with natural boundary conditions.] Further principles of dynamics workings such as Routhian reduction and the Dirac procedure are shown to have parallel counterparts for this new formalism. One advantage of the new scheme is that the corresponding actions are more manifestly relational. While the electric potential is usually regarded as a multiplier coordinate and Arnowitt, Deser and Misner have regarded the lapse and shift likewise, this paper's scheme considers new {\it flux}, {\it instant} and {\it grid} variables whose corresponding velocities are, respectively, the abovementioned previously used variables. This paper's way of thinking about gauge theory furthermore admits interesting generalizations, which shall be provided in a second paper.Comment: 11 page

Transverse modulational instability of partially incoherent soliton stripes

Based on the Wigner distribution approach, an analysis of the effect of partial incoherence on the transverse instability of soliton structures in nonlinear Kerr media is presented. It is explicitly shown, that for a Lorentzian incoherence spectrum the partial incoherence gives rise to a damping which counteracts, and tends to suppress, the transverse instability growth. However, the general picture is more complicated and it is shown that the effect of the partial incoherence depends crucially on the form of the incoherence spectrum. In fact, for spectra with finite rms-width, the partial incoherence may even increase both the growth rate and the range of unstable, transverse wave numbers.Comment: 5 pages, submitted to Phys. Rev.

Vorticity interaction effects on blunt bodies

Numerical solutions of the viscous shock layer equations governing laminar and turbulent flows of a perfect gas and radiating and nonradiating mixtures of perfect gases in chemical equilibrium are presented for hypersonic flow over spherically blunted cones and hyperboloids. Turbulent properties are described in terms of the classical mixing length. Results are compared with boundary layer and inviscid flowfield solutions; agreement with inviscid flowfield data is satisfactory. Agreement with boundary layer solutions is good except in regions of strong vorticity interaction; in these flow regions, the viscous shock layer solutions appear to be more satisfactory than the boundary layer solutions. Boundary conditions suitable for hypersonic viscous shock layers are devised for an advanced turbulence theory

DEVELOPMENT AT THE URBAN FRINGE AND BEYOND: IMPACTS ON AGRICULTURE AND RURAL LAND

Land development in the United States is following two routes: expansion of urban areas and large-lot development (greater than 1 acre per house) in rural areas. Urban expansion claimed more than 1 million acres per year between 1960 and 1990, yet is not seen as a threat to most farming, although it may reduce production of some high-value or specialty crops. The consequences of continued largelot development may be less sanguine, since it consumes much more land per unit of housing than the typical suburb. Controlling growth and planning for it are the domains of State and local governments. The Federal Government may be able to help them in such areas as building capacity to plan and control growth, providing financial incentives for channeling growth in desirable directions, or coordinating local, regional, and State efforts.land development, sprawl, large-lot housing, land zoning, population growth, housing, specialty agriculture, high-value agriculture, rural amenities, smart growth, Land Economics/Use,

Experimental investigation of a large-scale, two-dimensional, mixed-compression inlet system: Internal performance and drag at transonic conditions, free stream Mach equals 0.6 to 1.28

A large scale, variable-geometry inlet system with a design Mach number of 3.0 was tested at Mach numbers from 0.6 to 1.28. Variable features for off-design operation are an adjustable-height ramp system and a translating cowl. Experimental results are presented for transonic ramp and cowl positions showing the effect of throat boundary layer bleed and vortex generators on engine-face performance. Detailed pressure and force-balance data are used to evaluate transonic drag characteristics

Quantum Cosmological Relational Model of Shape and Scale in 1-d

Relational particle models are useful toy models for quantum cosmology and the problem of time in quantum general relativity. This paper shows how to extend existing work on concrete examples of relational particle models in 1-d to include a notion of scale. This is useful as regards forming a tight analogy with quantum cosmology and the emergent semiclassical time and hidden time approaches to the problem of time. This paper shows furthermore that the correspondence between relational particle models and classical and quantum cosmology can be strengthened using judicious choices of the mechanical potential. This gives relational particle mechanics models with analogues of spatial curvature, cosmological constant, dust and radiation terms. A number of these models are then tractable at the quantum level. These models can be used to study important issues 1) in canonical quantum gravity: the problem of time, the semiclassical approach to it and timeless approaches to it (such as the naive Schrodinger interpretation and records theory). 2) In quantum cosmology, such as in the investigation of uniform states, robustness, and the qualitative understanding of the origin of structure formation.Comment: References and some more motivation adde

Evaluation of a high performance, fixed-ratio, traction drive

A test program was initiated to evaluate the key operational and performance factors associated with the Nasvytis multiroller concept. Two sets of Nasvytis drives, each of slightly geometry, were parametrically tested on a back to back test stand. Initial results from these tests are reported. One of these units was later retrofitted to the power turbine of an automotive gas turbine engine and dynamometer tested

Shallow grooves in journal improve air bearing performance

Bearing designs, which shape the surface to create artificial fluid-film wedges in the absence of any applied radial load, generate radial restoring forces to keep journals from whirling. Helical- or herringbone-grooved journals or rotors show most promise of stable operation, with no sacrifice in load capacity