Design, Assessment, and Trajectory Control of a Novel Decoupled Robotic Nanomanipulator

Abstract

To avoid the problems of low bandwidth or complex structure brought by conventional serial and parallel mechanisms, a novel decoupled robotic nanomanipulator (DRNM) with a hybrid configuration is conceived in this article to enable fast nanoscale manipulation. The proposed DRNM employs a new hybrid compliant structure to actuate the terminal platform and decouple the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -axial motions. The unique hybrid mechanism is devised using two H-shaped parallelogram flexures that are assembled in a serial manner and actuated in a parallel manner, bringing in the merits of a flexible terminal platform, compact structure, good decoupling, and wide bandwidth in working directions. To enhance the dynamic positioning performance of the proposed DRNM, a run-to-run-position-forward-based integral controller that can handle the hysteresis nonlinearity of the piezoelectric actuator with adaptive zero-point parameter is further designed. The DRNM prototype is tested having an in-plane resonant frequency of 2005 Hz and a cross coupling of 0.88%. While tracking a circular trajectory with a diameter of 3 µm at a frequency of 20 Hz, the DRNM exhibits a maximum filtered tracking error of 4.3 nm.