Hamilton-Jacobi theory for degenerate Lagrangian systems with holonomic and nonholonomic constraints

We extend Hamilton-Jacobi theory to Lagrange-Dirac (or implicit Lagrangian) systems, a generalized formulation of Lagrangian mechanics that can incorporate degenerate Lagrangians as well as holonomic and nonholonomic constraints. We refer to the generalized Hamilton Jacobi equation as the Dirac-Hamilton-Jacobi equation. For non-degenerate Lagrangian systems with nonholonomic constraints, the theory specializes to the recently developed nonholonomic Hamilton Jacobi theory. We are particularly interested in applications to a certain class of degenerate nonholonomic Lagrangian systems with symmetries, which we refer to as weakly degenerate Chaplygin systems, that arise as simplified models of nonholonomic mechanical systems; these systems are shown to reduce to non-degenerate almost Hamiltonian systems, i.e., generalized Hamiltonian systems defined with non-closed two-forms. Accordingly, the Dirac Hamilton Jacobi equation reduces to a variant of the nonholonomic Hamilton Jacobi equation associated with the reduced system. We illustrate through a few examples how the Dirac Hamilton Jacobi equation can be used to exactly integrate the equations of motion. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4736733]