Information Consensus based Coordinated Control of Multi-Hydraulic Cylinders for Skin Stretch Forming Machine

In the aviation industry, the skin stretch forming machine, which is capable of stretching metal sheets into various complex curved thin-walled structural parts by the coordinated operation of multiple hydraulic cylinders, plays an important role in the manufacturing of aircraft. In this paper, the coordinated control of multi-hydraulic cylinders for skin stretch forming machines is addressed. Firstly, the working principle of the skin stretch forming machine and the dynamic model of hydraulic cylinders are analyzed. Then, a nonlinear disturbance observer is designed to estimate the parameter uncertainties and external disturbances of hydraulic cylinders. After that, an information consensus-based coordinated control algorithm is proposed by deploying the backstepping control method, which realizes the cooperative control of multiple hydraulic cylinders in the stretching process by addressing communication errors between adjacent cylinders and between followers and the leader. Finally, the feasibility and effectiveness of the proposed control algorithm are validated through both numerical simulations and experimental verification.