Precision-positioning adaptive controller for swing elimination in three-dimensional overhead cranes with distributed mass beams.

As a type of dispensable transport tool, overhead cranes are extensively applied in large industrial sites to transport containers and goods due to their extraordinary convenience and efficiency. However, various transport requirements and working environments may cause some adverse effects for overhead crane control. In particular, in some transport tasks, distributed-mass beams (DMB) are required to be transported smoothly to a specific position. Hence, most existing controllers designed for crane systems with point-mass payload (PMP) cannot meet the control requirements. For example, controllers designed for crane systems with PMP do not consider the moment of inertia of DMB, thus, the residual payload swing caused by the moment of inertia cannot be completely suppressed, which may cause safety risks. Additionally, due to various working environments, inaccurate estimation of frictions can result in errors in positioning. To solve the above issues, this paper conducts the dynamic analysis of three-dimensional (3-D) overhead crane systems with DMB and designs an improved adaptive controller which can provide favorable control for state variables. In particular, the proposed update laws can compensate for the uncertainties of crane systems. Based on a tracking trajectory, the trolley and guide rail can both reach the preset position, and the swing angles are also well eliminated throughout the transport process. The stability of the control system is proven theoretically, and the performance of the proposed controller is verified by comparative experiments.