Workspace-based hybrid force position posture alignment for high quality aircraft assembly of large-scale components

The high-quality assembly of Large Aircraft Components (LACs) is essential in modern aviation manufacturing. Numerical control locators are employed for the posture adjustment of LAC, yet the system’s multi-input multi-output, nonlinearity, and strong coupling presents significant challenges. The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality. Hence, a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force. Firstly, an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint. Then, the posture error is integrated into the online position axis control to ensure tracking the ideal posture, while the force control axis compensates for posture deviation by minimizing internal force, thereby achieving high precision and low internal force. Finally, the effectiveness was demonstrated through experiments. The root mean square errors of orientation and position are 10^-4 rad and 0.1 mm, respectively. A reduction in internal force can range from 10.96% to 57.4% compared to the traditional method. Key points’ max position error is decreased from 0.32 mm to 0.18 mm, satisfying the 0.5 mm tolerance. Therefore, the proposed method will help promote the development of high-performance manufacturing.