Motion Trajectory Tracking and Sway Reduction for Double-Pendulum Overhead Cranes Using Improved Adaptive Control Without Velocity Feedback

The dynamic characteristics of 3-D overhead cranes with double-pendulum effect are complex, which makes the controller design particularly challenging. Besides, in actual conditions, external disturbances cause interference to the system, and the model parameters are uncertain, which further increase the difficulty of controller design. In order to improve the control performance, two composite displacement signals are constructed to increase the coupling relationship of state vectors, and then new error signals and a total mechanicallike energy function are derived. Based on the new energy function, an adaptive control method with enhanced swing suppression is derived. Furthermore, considering the costs of sensors, the velocity signals cannot be obtained directly in many cases of practical application. Hence, auxiliary functions are constructed to replace the velocity feedback signals, and then an improved adaptive tracking control strategy is proposed. Theoretical analysis and experimental results prove that the proposed method can fulfill the control task. Its control result is significantly better than that of the comparison methods. Meanwhile, the experimental results in three different scenarios verify the strong robustness of this method.