Visual Servoing of a Flexible Gantry Crane With a Sway Range Constraint

Abstract

In this letter, the problem of moving a gantry crane with a flexible cable and a sway range constraint to the desired position is solved. The dynamic model of the flexible gantry crane system is built based on the absolute nodal coordinate formulation (ANCF), which is useful for analyzing flexible bodies. A novel controller is proposed to control the gantry crane to the desired position and guarantee the sway range constraint. Moreover, with the help of an eye-in-hand camera, an adaptive law is developed to detect the position of the object with respect to the base frame. The convergence of the cable's position to the desired position, the satisfaction of the sway range constraint, and the convergence of the estimated object's position to the real value are rigorously verified based on the Lyapunov theory. Simulation demonstrates the effectiveness of the proposed controller.