Dynamic Model of a Compliant 3PRS Parallel Mechanism for Micromilling

The objective of this work is to develop a manipulator of 5 degrees of freedom for micromilling. It consists of a XY stage under a 3PRS compliant parallel mechanism, obtaining the advantages of the compliant joints as are higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 μm. In this work, the dynamics of the compliant stage will be developed. The modelling approach is based on the use of the Principle of Energy Equivalence combined with the Boltzmann-Hamel equations to analyze the rotational dynamics of the platform. A pseudo-rigid model has been assumed for the compliant joints, calculating the flexural and torsional stiffness by FEA. Finally, a prototype has been built and some preliminary results are shown comparing the simulation and the measurements. The authors of this paper wish to acknowledge the financial support received from the Spanish Government via the Ministerio de Economía y Competitividad (Project DPI2015-64450-R), the ERDF of the European Union, the Government of the Basque Country (Project GIC07/78, IT445-10 and SAIOTEK 2013 SAI13/245, SPC13UN011), and the University of the Basque Country (Zabalduz-2012)