Refined Dynamic Modeling and Performance Evaluation of a Novel Large Loading SCARA Parallel Robot

This paper concentrates on a SCARA parallel robot with two closed-loop substructures within any branch, aiming to establish its precise dynamic model and analyze its dynamic performance under the framework of screw theory. First, the configuration characteristics and mobility properties of this robot are analyzed in detail. Based on the inverse position solution, the visualization of the robot’s reachable workspace is achieved. Subsequently, utilizing the superposition principle of screw theory and the Lie screws method, the velocity and acceleration mappings between individual joints and the end-effector are constructed, and a complete dynamic model of system is established based on the principle of virtual work. To validate model accuracy, a physical simulation model is built using co-simulation between SolidWorks and Simscape for comparison. Introduction of error evaluation metrics reveals that: the maximum absolute error of the driving torque for each limb is less than 0.0123 N · m, the root mean squared error is less than 0.0067 N · m, and the mean relative error is below 0.47%, fully confirming the accuracy of the established dynamic model. Finally, fully considering the influence of inertial terms on driving torques, the dynamic performance of the robot is evaluated based on the Joint-reflected Inertia (JRI) index,Coefficient of Variation of joint-space Inertia (CVI) index and Dynamic Dexterity Index (DDI), laying a theoretical foundation for the subsequent integrated high-speed, high-stiffness design and prototype development of this robot in future.