Modeling and a cross-coupling compensation control methodology of a large range 3-DOF micropositioner with low parasitic motions

The rapid developments in precision applications have increased the demand for high accuracy large range planar 3-DOF micropositioning mechanisms. However, the parasitic motions and cross-axis coupling in these mechanisms pose real challenges for their resolution and accuracy. In this paper, the parasitic motions in a large range 3-DOF XYΘ was investigated and reduced by utilizing constrained prismatic joints. Moreover, analytical modeling was studied and systematically derived to enable the design of a model-based control methodology. Furthermore, a backstepping sliding mode control method combined with an adaptive fuzzy neural network disturbance observer was proposed to control the mechanism and alleviate the cross-axis coupling effects. The control system stability was proved using the Lyapunov approach, and the performance was verified experimentally through several trajectory tracking tests. The results showed the effectiveness of the proposed control technique to achieve high tracking performance, and overcome the cross-axis coupling issues.