Robust control with a novel 6-DOF dynamic model of indoor bridge crane for suppressing vertical vibration

A new six-degree-of-freedom dynamic model is established to more completely characterize the physical features of a bridge crane. Previous works on this type of crane control system have focused primarily on trajectory tracking and anti-sway of the cargo, but the problem of vertical vibration attenuation is rarely studied. Although this type of vibration has a much smaller amplitude than the other two horizontal vibrations, it has severe negative impacts on system durability due to fatigue failure, energy consumption level, and operational efficiency. In this study, a robust integral sliding mode control algorithm is designed based on Lyapunov and Barbalat criteria to ensure the convergence of the tracking errors to the origin. Consequently, not only does the control law minimize the vertical vibration of cargo, but also it guarantees the conventional working requirements even when the system is influenced by external disturbances. The suitability of the proposed dynamic model and the effectiveness of the control algorithms are investigated by numerical simulations based on the system parameters of a real-work crane. On the one hand, the similarity of physical characteristics of the built model with the actual model can confirm the correctness of the model qualitatively and, on the other hand, through simulation of the system driven by the proposed controller and the traditional PID controller (whose characteristics are quite similar to that of the crane driver) tracking the given reference trajectory. With the influence of noise, the efficiency and feasibility of the whole work can be clearly realized. Therefore, the development of the model-based controller can be a premise for application in industrial crane platforms, especially for systems with high technical requirements.