DYNAMIC MODELING OF A SMART MATERIALS ROBOT

Three dynamic models of a smart materials robot are presented, First, Hamilton's approach is adopted to derive an accurate model expressed i n partial differential equations, which is too complicated to be appli cable in engineering practice, Based on the partial differential equat ions model, the assumed modes method and the finite element method are employed to derive two finite dimensional models in the forms of ordi nary differential equations, which are readily usable for controller d esign. All of the models show that the model of a smart materials robo t cannot be simply taken to be the same as that of a pure flexible rob ot, and the parameters of the smart materials robot should be properly chosen to avoid the divergent open-loop responses, For completeness, both mechanical dynamics and electrical dynamics are explicitly includ ed in all of these models, although it is shown analytically and numer ically that the latter dynamics can be omitted in engineering applicat ions. Comparative studies between the assumed modes method model and t he finite element method model are carried out by numerical simulation s in both time and frequency domains to verify the correctness of the models and to analyze the performance of the system.