Measurement uncertainty analysis of a measurement flexure hinge in a torque standard machine

Abstract

Abstract. An alternative method to using strain gauges to measure FT (please see Appendix A for a list of definitions) and TM under a static multi-component load by using a hinge flexure (also called measurement flexure or MF) is presented. Its usage in the 5 MN m torque standard machine (TSM) at the Physikalisch-Technische Bundesanstalt (PTB) to detect calibration torque moment shunts is described. The working principle consists of a displacement measurement by an interferometer and the determination of the MF stiffness in a special CSU. Essential measurement uncertainty influences, such as stiffness determination and measurement conditions, are discussed and quantified. The measurement uncertainty budget for this measurement principle is presented. A FE validation for the MF is discussed.

Experimental Results of Measurement Hinge Flexure Stiffness Determination

“…Another adjustment was necessary because the FE analysis of the torque load scenario in [5] implied there was a major difference in the torque stiffness determination when an axial force was applied onto the MF while also applying torque. Therefore, an additional traverse was designed to apply an axial force.…”

“…The modification mentioned in the section above and a few restrictions during the measurement series necessitated a refinement of the measurement uncertainty budget (MUB) presented in [5].…”

Bionic Stepping Motors Driven by Piezoelectric Materials

“…In order to achieve angular displacements of piezoelectric motors, considerable efforts have been made by different researchers. For example, flexure hinges, revolute pairs, and other methods are utilized to transform linear displacements into angular displacements [37][38][39][40][41][42]. Flexure hinges are a kind of deformable mechanism to guide movements, which consist of flexible parts and rigid parts.…”

“…Flexure hinges are a kind of deformable mechanism to guide movements, which consist of flexible parts and rigid parts. The flexible parts with small stiffness and the rigid parts with large stiffness are designed and machined from a single piece of material [37][38][39][40][41][42]. With the given deformations and constraints of flexible parts, the rigid parts can move at certain degrees of freedom.…”

“…With the given deformations and constraints of flexible parts, the rigid parts can move at certain degrees of freedom. Owing to the advantages of compliant and repeatable motions, compact structures, small inertial mass, no backlash, and friction, the flexure hinges are widely utilized in piezoelectric motors, especially in stepping piezoelectric motors [37][38][39][40][41][42]. Furthermore, with the designed flexure hinges mechanisms, we can not only obtain the angular displacements but also multiply and enlarge the small deformations of piezoelectric materials [40][41][42].…”