A new approach of modelling vibrations for intelligent robotized structures

Intelligent precise and fast robotized systems must take into account the flexible and torsional nature of their structure. This leads to theoretical infinite dimensional controllers. We present in the framework of resonant behaviors an eigenfrequency invariance property for loaded flexural and torsional deformable bodies which is very suitable for modelling these new robots as the resulting model is finite dimensional of low order and can be determined by an a priori precision given by the designer. We found that under a preload condition each eigenfrequency is invariant versus the tipload. To further improve this result, the role of passive system parameters has been studied. We show that compliant behaviors at mechanical joints create a new order on the system which leads to a large invariance property. A compliant mechanical joint diminishes drastically the preload condition.