Multi-Axis Loading on Multiple Flanges of Intermediate Aero-Engine Case Based on Parallel Robotic Simulation

Applying multi-axis force to an intermediate aero-engine case to simulate its working force environment is critical to accurately evaluate its mechanical properties. This paper presents a multi-axis loading method based on parallel robots to simultaneously add complex forces on two mounting flanges of the aero-engine case. The multi-axis loading device (MLD) for each flange was developed based on a 6-UPS parallel robot. Its geometric structure was presented and kinematics was analyzed. The static mapping between the multi-axis force and linear actuating force was derived on each flange, and the influence of loading two flanges at the same time was discussed. A force control algorithm based on admittance control was designed and the multi-axis loading on two flanges of aero-engine case was validated by simulations. Results illustrate that the MLD could apply multi-axis force to each flange and using two MLDs could simultaneously load two flanges. This suggests that parallel robots could be implemented as a general system to produce complex force environments for a series of aero-engine cases with multiple mounting flanges, which could mimic their actual working loads by ground tests to improve the accuracy of the mechanical property tests.