Precession Driven Structural and Spatial Accuracy Assessment of Six -Axis Robotic Arm via FEA and 6D Laser Interferometry

Abstract Stabilizing high structural stiffness and spatial motion accuracy is a paramount challenge in industrial multi-axis robotic systems, particularly under dynamic loading and large workspace operation. This work presents a unified multi-domain approach to assess and optimize the mechanical performance of a six-axis robotic arm by combining finite element analysis (FEA), experimental modal analysis (EMA), spatial deformation mapping, and 6D laser interferometry. Modal simulations identify the first three natural frequencies as 108.9 Hz, 113.6 Hz, and 259.1 Hz, with experimental validation confirming modal peaks at 109.0 Hz, 114.0 Hz, and 259.0 Hz, respectively error < 1% , indicating high fidelity in frequency prediction. Spatial deformation varied between 15.3 µm to 25.7 µm, and frequency–deformation correlation analysis mapped optimized ≥ 105 Hz, ≤ 20 µm and risk-prone regions throughout the workspace. Real-time six-degree-of-freedom validation using a 6D laser interferometer indicated Y-axis positioning accuracy of 14.0 µm and peak X-axis deviation of 113.0 µm at extreme lower zones −350 mm. The integrated framework provides a robust foundation for stiffness-aware task allocation, workspace partitioning, and structural optimization. The results offer practical insights into the deployment of high-precision robotic platforms in aerospace, micro-assembly, and biomedical automation.