Symbolic derivation of open-loop dynamic models of multibody mechatronic systems for control purpose. A case study: The LISA Technology Package.

This paper describes a collection of methods for the automatic derivation of the open loop dynamic models of mechatronic systems. These methods may be employed with a general-purpose computer algebra system like Mathematica or MAPLE (examples are given for Mathematica). The symbolic mathematical models produced in this way are suitable to form "plant models" that may be exploited for the design of control systems. In this paper the LISA Technology Package (LISA stands for laser Interferometer Space Antenna, an ESA-NASA cornerstone mission planned for in-orbit gravitational wave detection) is assumed as a case study that has many interesting aspects for which symbolic modelling is useful. The work starts with an introductory review of existing multibody systems, especially symbolic ones (like Dynaflex, Autosim. TsiProPac etc.), in the view of their use for obtaining models for control design purpose. Then, a set of methods for symbolic modelling of multibody systems are introduced and applied to the development and linearisation of equations of the LISA Technology Package.