Improved input shaping technique for a nonlinear system

This paper presents development and implementation of an improved input shaping technique for nonlinear systems. In this work, a nonlinear 3 dimensional gantry crane is considered where a complete nonlinear mathematical model of a lab-scaled gantry crane with variable cable length is simulated. An improved scheme for implementation of Unity Magnitude - Zero Vibration (UM-ZV) and Zero Vibration (ZV) shapers to shape the input signal in rising and falling edges is designed which enables an operator to move the gantry crane without problem with motion-induced sway. Simulation studies show that the proposed scheme resulted in lower overall sway for rail and trolley of the crane as compared to conventional shapers designed using gain-delay elements for payload sway reduction. Lower magnitudes of transient and residual sways are also achieved.