Comparative analysis on the performance of different types of input- and command-shaping controllers in minimizing payload residual vibration of an overhead crane with an inclined supporting track

Reducing the effects of external disturbance on overhead crane systems is crucial, as they can impair the controller performance and cause excessive vibrations or oscillations of the payloads. One such external disturbance is the inclination of the supporting track of the crane trolley, which causes the system dynamics model to change. An open-loop control strategy is widely utilized to control the payload sway motion and generally does not require any alterations in the physical structure of a system or the installation of sensors and/or actuators. Input and command shaping are two common open-loop control techniques applied to control overhead cranes. In this paper, the effect of moving an overhead crane system along an inclined supporting track is investigated. In addition, the ability of different types of input- and command-shaping control schemes to suppress the residual vibrations due to trolley track inclination is demonstrated. Two types of input-shaping controllers, which are double-step, zero vibration, and one command waveform (WF) shaper based on a trigonometric function, are used and tested. A linear equation of motion of the overhead crane resting on an inclined surface is developed to simulate the overhead crane and payload motion. The effectiveness of the different types of open-loop controllers to suppress residual vibrations is verified by both simulation and experimental results. In addition, a new WF command shaper is proposed and designed to overcome track inclination while eliminating payload residual vibration. A comprehensive comparative analysis, both numerically and experimentally, is performed on the new proposed shaper to measure its effectiveness in handling inclination when compared to other types of open-loop controllers. The new shaper outperforms other controllers in eliminating payload residual vibration for a wider range of inclination angles.