A Parametric Study of Mechanical Cross-Coupling in Parallel-Kinematics Piezo-Flexural Nano-Positioning Systems

Abstract

Piezo-electric nano-positioning stages are being widely used in applications in which precision and accuracy in the order of nano, and high scanning speeds are paramount. This paper presents a Finite Element Analysis (FEA) of the parallel piezo-flexural nano-positioning (PPNP) stages to investigate motion interference between their different axes. Cross-coupling is one of the significant contributors to undesirable runouts in the precision positioning of PPNP actuators. Using ABAQUS/CAE 2018 software, a 3D model of a PPNP stage was developed. The model consists of a central elastic body connected to a fixed frame through four flexural hinges. A cylindrical stack of multiple piezoelectric disks is placed between the moving central body and the fixed frame. Extensive simulations were carried out for three different friction coefficients in the piezoelectric disks' contact surfaces, different frame materials, and different geometrical configurations of the stage and the hinges. As a result, it was observed that the primary root cause of the mechanical crosscoupling effect could be realized in the combination of the slip and rotation of the piezoelectric disks due to their frictional behavior with the stage moving in the tangential direction, concurrent with changes in the geometry of the stage.

Reliability-based energy scheduling of active buildings subject to renewable energy and demand uncertainty

“…These approaches, however, may generate substantial mistakes when dealing with issues involving highly dependent out-crossing occurrences. The Markov process model [38] and joint out-crossing rate [39] were used to characterize the dependency between distinct out-crossing occurrences. Although the effectiveness of first-passage based approaches has improved significantly over the past two decades, precisely determining the first-time out-crossing rate for situations with complicated mathematical features remains challenging.…”