Dynamic behavior and kinematic joint wear characteristics study of rigid-flexible hybrid mechanism considering spatial revolute joint clearance

Abstract

As industrial production increasingly demands higher precision, performance and stability requirements for advanced mechanisms have intensified exponentially, making the investigation of their dynamic behaviors critically important. Among the predominant factors compromising the precision and robustness of mechanism actuators, elastic deformation of structural components and kinematic joint clearances have been identified as significant contributors. While current research on clearance-induced dynamic behaviors predominantly focuses on planar multi-link mechanisms or simple spatial parallel mechanisms. Studies addressing hybrid mechanism containing three-dimensional(3D) revolute joint clearances remain remarkably limited, and even fewer studies consider the flexible effects of components alongside the wear characteristics of kinematic joints clearance in such hybrid systems. To address these research gaps, this paper investigates the dynamic response, reliability and wear characteristics of kinematic joints in a 3-PRPaR-RUPUR spatial redundant rigid-flexible hybrid mechanism. Firstly, a 3D revolute joint clearance model is established. Next, a 3D two-node spatial beam element model is developed using the absolute nodal coordinate form(ANCF). Subsequently, a wear model for revolute joint clearances is given based on the Archard model. Finally, a dynamic model of the rigid-flexible hybrid mechanism, considering spatial revolute joint clearances, is formulated utilizing the Lagrange multiplier method. This investigation systematically quantifies the effects of component flexibility, clearance size, and multi-clearance configurations on the dynamic response, reliability of the moving platform and wear characteristics of clearance joints in the rigid-flexible hybrid mechanism. The findings aim to establish a systematic theoretical foundation for the study of high-precision, high-performance mechanism dynamics, reliability and the wear characteristics of kinematic joints with clearances.