Moving the suspended load of an overhead crane along a pre-specified path: A non-time based approach

This paper introduces a noncolocated non-time based regulator for the path tracking control of the suspended load of a four degrees of freedom gantry crane. The regulator is named Delayed Reference Noncolocated Control (DRNC). The DRNC control action is exerted by modifying the moving platform reference trajectory. Such a goal is achieved by both shifting trajectory execution in time, and modifying the platform path with respect to the reference path defined for the load. Simulation results prove the capability of the method to ensure extremely precise path tracking, while ensuring very simple controller implementation, which makes it well suited for industrial application.