Monolithic Six-DOF Parallel Positioning System for High-precision and Large-range Applications

TL;DR

This paper presents a compact, high-precision six-DOF parallel positioning system with large range, high resolution, and repeatability, validated through modeling, manufacturing, and experimental testing.

Contribution

It introduces a novel monolithic six-DOF positioner design with 3D-printed ABS components, piezoelectric actuation, and capacitive sensing, achieving nanometer-scale accuracy over a large stroke.

Findings

Achieved positioning resolution of 10.5nm x 10.5nm x 15nm and 1.8μrad x 1.3μrad x 0.5μrad.

Validated nanometer-scale spatial accuracy within the full stroke range.

Demonstrated potential applications in microsurgery, micro-assembly, and pick-and-place tasks.

Abstract

A compact large-range six-degrees-of-freedom (six-DOF) parallel positioning system with high resolution, high resonant frequency, and high repeatability was proposed. It mainly consists of three identical kinematic sections. Each kinematic section consists of two identical displacement amplification and guiding mechanisms, which are finally connected to a limb. Each limb was designed with a universal joint at each end and connected to a moving stage. A computational model of the positioner was built in the ANSYS software package, hence, the input stiffness, output compliance, range, and modal analysis of the system were found. Furthermore, a monolithic prototype made of Acrylonitrile Butadiene Styrene (ABS) was successfully manufactured by the 3D-printing process. It was actuated and sensed by piezoelectric actuators (PEAs) and capacitive displacement sensors, respectively. Finally, the performances of this proposed positioner were experimentally investigated. The positioning resolution was achieved as 10.5nm {\times} 10.5nm {\times} 15nm {\times} 1.8{\mu}rad {\times} 1.3{\mu}rad {\times} 0.5{\mu}rad. The experimental results validate the behavior and capabilities of the proposed positioning system, and also verify the nanometer-scale spatial positioning accuracy within the overall stroke range. Practical applications of the proposed system can be expanded to pick-and-place manipulation, vibration-canceling in microsurgery/micro-assembly, and collaborative manipulators systems.