Abstract
This paper presents the design, modeling, and robust control of a novel 3-degree-of-freedom (3-DOF) compliant parallel manipulator (CPM) designed for high-precision micro-positioning applications. Traditional rigid-body manipulators suffer from backlash, friction, and wear, which limit their precision in the sub-micron regime. To overcome these limitations, we propose a monolithic CPM utilizing right-circular flexure hinges that provide frictionless, smooth, and repeatable motion. The kinematic and dynamic models of the CPM are derived using the compliance matrix method and verified via Finite Element Analysis (FEA). To address the inherent challenges of piezoelectric actuator hysteresis, cross-axis coupling, and payload variations, a robust sliding mode control (SMC) scheme integrated with a perturbation observer is developed. Experimental investigations are conducted to evaluate the tracking performance and robustness of the developed system. The experimental results demonstrate that the proposed robust SMC successfully mitigates chattering and achieves high-accuracy trajectory tracking, yielding a root-mean-square tracking error of less than 45 nm for a circular trajectory of 10 µm radius. Furthermore, the controller exhibits excellent robustness against payload variations up to 1.5 kg, highlighting its suitability for high-precision industrial applications such as semiconductor manufacturing and bio-micromanipulation.
