Modeling and Control of a Bifilar Crane Payload

This paper presents a modeling technique and a controller for an underactuated crane payload. The crane payload is modeled as a bifilar pendulum. The payload is attached to a sheave block, such that a cable can freely run to either side. This configuration is often used in different types of cranes, including offshore cranes. To achieve asymptotic stability in the absence of damping, we propose a controller based on an energy approach and the passivity properties of the system. We prove stability of the system with the proposed controller using LaSalle's invariance principle. The control performance is studied in the numerical simulations. The simulation results show that all the states of the closed-loop system with coupled sway and skew dynamics converge to the origin.