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

• We introduce the DRNC non-time based regulator for path tracking in overhead cranes.
• The DRNC ensures accurate noncolocated motion control of the crane suspended load.
• Time shifting of the load trajectory and an adaption of the trolley path are made.
• Two representative tests are presented and discussed to validate the approach.
• Effectiveness and ease of implementation make the method industrially relevant.

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.