Control of a container crane: fast traversing, and residual sway control from the perspective of controlling an underactuated system

In this paper the sway-control problem of a container crane is investigated. The control loop is divided into two stages. The first stage is a modified time optimal control for trolley traversing. The velocity command for trolley traversing consists of three components; a reference velocity and two feedback signals for compensating the deviations of trolley and sway angle from their desired trajectories. For trolley´s exact positioning the trolley dynamics is identified via an error equation identifier structure. The second stage is a nonlinear residual sway control that starts at the end of first stage. The control design for the second stage is investigated from the perspective of controlling an underactuated system, and the control law combines the feedback linearization and variable structure control