Affiliations: Instituto Superior Técnico, Departamento de
Engenharia Mecânica, Av. Rovisco Pais, 1049-001 Lisboa, Portugal | Escola Superior de Tecnologia de Setúbal, Campus
do IPS, 2914-508 Setúbal, Portugal
Abstract: This paper presents an integrated methodology for optimal design and
control of nonlinear flexible mechanical systems, including minimum time
problems. This formulation is implemented in an optimum design code and it is
applied to the nonlinear behavior dynamic response. Damping and stiffness
characteristics plus control driven forces are considered as decision
variables. A conceptual separation between time variant and time invariant
design parameters is presented, this way including the design space into the
control space and considering the design variables as control variables not
depending on time. By using time integrals through all the derivations, design
and control problems are unified. In the optimization process we can use both
types of variables simultaneously or by interdependent levels. For treating
minimum time problems, a unit time interval is mapped onto the original time
interval, then treating equally time variant and time invariant problems. The
dynamic response and its sensitivity are discretized via space-time finite
elements, and may be integrated either by at-once integration or step-by-step.
Adjoint system approach is used to calculate the sensitivities.
Keywords: Minimum time design, nonlinear systems, dynamic response, space-time finite elements
