Modeling, mechanics and experimental investigation of perpetual vibration of serial-chain direct-drive flexible robotic system

Abstract

The domain of Flexible Robotic Systems (FRS) is an exciting ensemble of global robotics research of the present decade, which unfurls various real-time data like rheology, vibration, sensor fusion, and non-linear coupled dynamics for control. As some of these features, especially strain-induced deflection and vibration, are inherent in FRS, the design and prototype development of multiple degrees-of-freedom flexible robots is highly challenging. The paper addresses the aforementioned design paradigms of FRS through logical understanding by giving importance to the manufacturable design-variables. Further, these design issues for the firmware of higher-order FRS have been explained with a focus on the novel design and hardware development of a prototype multi-link serial-chain FRS fitted with a miniaturized gripper at the free end. Besides hardware realization, the paper brings out an interesting feature in experimental robotics, namely, the evaluation of the natural frequency of vibration of a flexible manipulator using real-time data on dynamic strain produced within its body. This niche methodology gets propelled by the data from multiple strain-detecting sensors placed judiciously over the links of the FRS. Guided by this lemma, a novel theoretical analysis of the optimal placement of strain-sensors over the external surface of the FRS is described. Additionally, the paper dwells on a novel scheme for dynamic analysis as well as control system logic for the developed FRS. This research provides a complete canvas of design, modeling, firmware development, and experimental ab initio evaluation of perpetual in-situ vibration of a typical serial-chain FRS