Symbolic computer methods to automatically formulate vehicle simulation codes

摘要: This dissertation deals with the modeling and computer simulation of multibody systems composed rigid bodies massless force- torque-producing elements. Multibody pertaining to ground vehicles are particular interest. The includes (1) a software design for representing system in symbolic form as set data objects bodies, points, forces, etc, (2) formalism (i.e., formal strategy deriving equations motion system) that is valid various types connections between (3) methods manipulate expressions automatically within formalism, (4) an interface analyst permits description unconventional moment-producing components, (5) generating constraint form, (6) way accommodate external numerical algorithms may have already been developed. The holonomic nonholonomic constraints, tree topologies, closed kinematical loops, scleronomic or rheonomic constraints continuously differentiable. Symbol manipulation techniques applied vector dyadic algebraic expressions, elements system, pieces analysis code. A package called AUTOSIM was written Lisp language validate demonstrate methods. using provides layout, output variables interest, "external" subroutines, and, some systems, descriptions conditions. Using symbol techniques, generates complete, self-contained Fortran program numerically computes specified response initial conditions, control inputs, disturbances. Six case studies included illustrate These include two (one rigid, nonslipping wheels, one slip angles tire characteristics), four-bar linkage, spacecraft vehicles, robot manipulator six links.