Dynamic Modeling and Transmission Characteristic Analysis of Integrated Linear Joints

To analyze the coupled behavior of integrated linear joints in precision robotics, this study develops a multibody dynamics framework to perform dynamic modeling and transmission characteristic analysis. The proposed model integrates the inverted planetary roller screw (IPRS) with a frameless motor, taking into account the centripetal excitations caused by rotor eccentricity and utilizing a continuous friction model. A set of global dynamic equations is established to comprehensively describe the radial, axial, and torsional interactions within the system. The results characterize the non-uniformity in internal load distribution and the coupling effects between radial and axial motions. Furthermore, a comprehensive analysis across time-domain, frequency-domain, and phase-space indicates that the joint maintains stability with quasi-periodic motion under complex excitation. This work establishes the fundamental connections between internal mechanical excitations and motion accuracy, providing a theoretical basis for refining the structure and precision control of integrated robotic actuators.