Partial feedback linearization and sliding mode techniques for 2D crane control

The overhead crane is an under-actuated system because its degree of freedom is larger than that of actuators. The three state variables of trolley motion, cargo lifting motion and cargo swing are controlled by two input signals composed of trolley driving and cargo lifting forces. In the present study, a novel non-linear control scheme for an overhead crane is proposed based on the combination of two control design techniques. The cargo swing vanishing mechanism is constructed using partial feedback linearization. Control of trolley and cargo tracking is designed based on the sliding mode technique. An anti-swing structure is then merged with the tracking scheme of the trolley and cargo hoisting motions to enable indirect control of the cargo swing angle. Both simulation and experimental results show that the combined controller not only stabilizes all trajectories of system states but also guarantees the robustness in which the shapes of system responses are consistently retained despite the wide variation in crane parameters.