Axial backlash of planetary roller screw mechanisms: Geometric modelling and Sobol's analysis of design parameters

Planetary roller screw mechanisms (PRSMs) are promising for the future all-electric aircraft flight controls because they allow transmission of high loads while being compact. However, impacts after axial backlash transit are critical when loads are alternate. In this paper, the influence of PRSM design parameters on the axial backlash is analysed. First, axial backlash is geometrically modelled. PRSM conformal contacts require multi-precision computation to avoid numerical cancellation. Second, Sobol's analysis is implemented on four industrial PRSMs. Results show that three out of six parameters are influential independently from the geometry considered. Controlling these parameters is thus mandatory for aeronautical applications.