Damping Enhancement and Positioning Control of Compliant Stages by Incorporating Rubber Shear Dampers

Abstract

Metal compliant stages are critical subsystems in numerous precision motion control applications. By incorporating feedback control, their performance can be further improved. However, metals have inherently very low damping and it may difficult to add external passive dampers. Such a low damping capability would limit the effectiveness of controller design and even cause instability. As a result, how to effectively enhancing damping capability of compliant stage under space constraint is a non-trivial issue in precision positioning control. In this work, we propose the use of PDMS rubber shear damper to enhance the effective material damping of compliant structures. The effect of PDMS dimension on the resulted damping capability is then investigated by both 3D printed plastic and wire-cut metallic testing structures. The experimental results indicate that the PDMS materials can indeed enhance the damping ratios. Finally, a plastic 3D printed compliant stage is designed as a prototype for validating the design in stage control. The experimental results indicated that the controlled performance is indeed improved by incorporated with PDMS shear damper. With the concept validated, it is possible to implement rubber shear dampers in real metallic compliant structure for enhancing their performance. Ultimately, it is also possible to integrate this concept with metallic 3D printing technology to achieve light weight, high stiffness, and high damping structures.