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A Stiffness Model for Control and Analysis of a MEMS Hexapod Nanopositioner



Hongliang Shi, Hai-Jun Su, Nicholas Dagalakis


This paper presents a stiffness based kinematic model for analysis and control of a MEMS flexure-based hexapod nanopositioner that was previously built by the National Institute of Standards and Technology (NIST). This nanopositioner is capable of producing high-resolution motions in 6 degrees of freedom (DOF) by actuating three planar X-Y positioning stages. Given a large number of flexure-based nanopositioners, the modeling and controller design has been a challenging task due to their inherent structural complexity and difficulties in measuring 6DOF positioning accuracy. In this paper, we discuss kinematic models for developing an open loop controller and an analytical analysis routine for this nanopositioner. These models include a novel model for calculating the nonlinear stiffness of the X-Y positioning stage and a stiffness based Jacobian matrix of the hexapod mechanism for controller. Compared with FE simulations, we conclude that the mean error of the X-Y stage control model is 1.93% within a 55 μm range of motion. To validate the control model, the top platform is commanded to trace a circle of diameter 20 μm. The result shows a mean error of 3.38%.
Journal of Mechanism and Machine Theory


Nanopositioning, MEMS, 3 DOF, Hexapod


Shi, H. , Su, H. and Dagalakis, N. (2014), A Stiffness Model for Control and Analysis of a MEMS Hexapod Nanopositioner, Journal of Mechanism and Machine Theory, [online], (Accessed July 21, 2024)


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Created July 8, 2014, Updated October 12, 2021