The Geometry of the Gibbs-Appell Equations and Gauss' Principle of Least Constraint

We present a generalisation of the Gibbs-Appell equations which is valid for general Lagrangians. The general form of the Gibbs-Appell equations is shown to be valid in the case when constraints and external forces are present. In the case when the Lagrangian is the kinetic energy with respect to a Riemannian metric, the Gibbs function is shown to be related to the kinetic energy on the tangent bundle of the configuration manifold with respect to the Sasaki metric. We also make a connection with the Gibbs-Appell equations and Gauss' principle of least constraint in the general case

A Symmetric Product for Vector Fields and its Geometric Meaning

We introduce the notion of geodesic invariance for distributions on manifolds with a linear connection. This is a natural weakening of the concept of a totally geodesic foliation to allow distributions which are not necessarily integrable. To test a distribution for geodesic invariance, we introduce a symmetric, vector field valued product on the set of vector fields on a manifold with a linear connection. This product serves the same purpose for geodesically invariant distributions as the Lie bracket serves for integrable distributions. The relationship of this product with connections in the bundle of linear frames is also discussed. As an application, we investigate geodesically invariant distributions associated with a left-invariant affine connection on a Lie group

Configuration Controllability of Simple Mechanical Control Systems

In this paper we present a definition of "configuration controllability" for mechanical systems whose Lagrangian is kinetic energy with respect to a Riemannian metric minus potential energy. A computable test for this new version of controllability is derived. This condition involves an object which we call the symmetric product. Of particular interest is a definition of "equilibrium controllability" for which we are able to derive computable sufficient conditions. Examples illustrate the theory

Configuration Controllability of Simple Mechanical Control Systems

In this paper we present a definition of 'configuration controllability' for mechanical systems whose Lagrangian is kinetic energy with respect to a Riemannian metric minus potential energy. A computable test for this new version of controllability is derived. This condition involves an object that we call the symmetric product. Of particular interest is a definition of 'equilibrium controllability' for which we are able to derive computable sufficient conditions. Examples illustrate the theory

A canonical treatment of line bundles over general projective spaces

Projective spaces for finite-dimensional vector spaces over general fields are considered. The geometry of these spaces and the theory of line bundles over these spaces is presented. Particularly, the space of global regular sections of these bundles is examined. Care is taken in two directions: (1) places where algebraic closedness of the field are important are pointed out; (2) basis free constructions are used exclusively

Generalised subbundles and distributions: A comprehensive review

Distributions, i.e., subsets of tangent bundles formed by piecing together subspaces of tangent spaces, are commonly encountered in the theory and application of differential geometry. Indeed, the theory of distributions is a fundamental part of mechanics and control theory. The theory of distributions is presented in a systematic way, and self-contained proofs are given of some of the major results. Parts of the theory are presented in the context of generalised subbundles of vector bundles. Special emphasis is placed on understanding the r\^ole of sheaves and understanding the distinctions between the smooth or finitely differentiable cases and the real analytic case. The Orbit Theorem and applications, including Frobenius's Theorem and theorems on the equivalence of families of vector fields, are considered in detail. Examples illustrate the phenomenon that can occur with generalised subbundles and distributions

The Ever-Protruding Stick in the Bundle: The Accommodation of Groundwater Rights in Texas Oil and Gas

In Texas, water is on everyone’s minds. Between a raging drought, an expanding oil and gas industry, and a whirring media machine, Texans find themselves in great conflict on how to maintain a tradition and a booming industry while conserving the very resource that allows their presence in the first place: water. Water has become an important part of oil and gas exploration, and this fact has kept it well within the reach of those who lease the mineral interests. Texas law promotes such exploration by granting these lessees the rights to the reasonable use of the land’s subsurface water so that they may be able to pursue their mineral interests. The limitations to this right loom large, however, as this right may begin to appear, in the minds of legislators, landowners, and the public-at-large, as not so reasonable. Existing Texas common-law limitations to this implied right may provide the door through which public interests slip into the traditional analyses and allow the interests of the landowner, the public, and the oil and gas industry to be served. This Comment suggests that changes in common law, regulations, and social and environmental trends portend broader interpretations of the limitations to Texas’s implied right of reasonable use of the surface. Specifically, this Comment suggests that the analysis provided by one limitation, the Accommodation Doctrine, may be the path by which Texas courts find that the oil and gas industry should accommodate public interests as well as specific surface-owner interests when pursuing their mineral rights

Aspects of Geometric Mechanics and Control of Mechanical Systems

Many interesting control systems are mechanical control systems. In spite of this, there has not been much effort to develop methods which use the special structure of mechanical systems to obtain analysis tools which are suitable for these systems. In this dissertation we take the first steps towards a methodical treatment of mechanical control systems. First we develop a framework for analysis of certain classes of mechanical control systems. In the Lagrangian formulation we study "simple mechanical control systems" whose Lagrangian is "kinetic energy minus potential energy." We propose a new and useful definition of controllability for these systems and obtain a computable set of conditions for this new version of controllability. We also obtain decompositions of simple mechanical systems in the case when they are not controllable. In the Hamiltonian formulation we study systems whose control vector fields are Hamiltonian. We obtain decompositions which describe the controllable and uncontrollable dynamics. In each case, the dynamics are shown to be Hamiltonian in a suitably general sense. Next we develop intrinsic descriptions of Lagrangian and Hamiltonian mechanics in the presence of external inputs. This development is a first step towards a control theory for general Lagrangian and Hamiltonian control systems. Systems with constraints are also studied. We first give a thorough overview of variational methods including a comparison of the "nonholonomic" and "vakonomic" methods. We also give a generalised definition for a constraint and, with this more general definition, we are able to give some preliminary controllability results for constrained systems