Super twisting and hierarchical sliding mode anti-swing control of boom crane

When the multiple mechanisms such as the slewing, luffing, and hoisting mechanisms work together, the boom crane has the strong coupling and underactuated characteristics which make it difficult to prevent the load swing. In this paper, a new dynamic model is established for the boom crane with the cooperative motion, where the kinetic energy and potential energy of the boom pitching motion are added to the Lagrange equation to calculate the driving torque of the luffing cylinder and the rotary mechanism. A super-twisting hierarchical sliding mode control method is proposed. The equivalent control law is obtained by a second-order sliding mode surface constructed with the driving and underactuated part, and the switching control law is designed by a second-order super-twisting sliding mode algorithm to suppress the chattering. The stability of the system is proved by Lyapunov function. The simulation and experiment results show that accurate anti-swing and strong robustness are achieved, and the system performance is significantly improved.