Design of a dynamic tribometer applied to piezoelectric Inertial Stepping Motors: In situ exploration of Stick-Slip principle

摘要

A realistic modeling of the inertia-drives-piezoelectric-actuator behavior, based on stick-slip principle, requires the establishment of an effective friction model. Indeed, macroscopic friction is largely influenced by both micrometric and nanoscale aspects, especially in stepping motor, whose step-size is in the same order of magnitude. To be used in different environments such as cryogenic, magnetic or vacuum, a change of the current tribological 1st-bodies would be necessary. This change could cause a friction variation which would impact the mechanical performances of the stepping motor such as its velocity, actuation force, step-size and lifetime, without being able to predict its evolution. Such prediction requires the reconstitution of the contact life through the evaluation of 1st and 3rd bodies flows to get the overall understanding of the tribological system. This contribution investigates the stick-slip instabilities through a systematic comparison of material-and-geometry interfaces. To do so, a new test bench was designed to observe, dynamically and in-situ, the friction with transparent lenses. To go further, results were compared to numerical modeling. As for a consequence, the developed friction model will be used to optimize the yield of Stepping Piezoelectric Actuators.