Control Schemes for Input Tracking and Anti-sway Control of a Gantry Crane

This paper presents investigations into the development of hybrid control schemes for input tracking and anti-sway control of a gantry crane system. A nonlinear overhead gantry crane system is considered and the dynamic model of the system is derived using the Euler-Lagrange formulation. To study the effectiveness of the controllers, an LQR control is developed for cart position control of a gantry crane. This is then extended to incorporate input shaper control schemes for anti-sway control of the system. The positive and new modified specified negative amplitude (SNA) input shapers are then designed based on the properties of the system for control of system sway. The new SNA is proposed to improve the robustness capability while increasing the speed of the system response. Simulation results of the response of the gantry crane with the controllers are presented in time and frequency domains. The performances of the of the hybrid control schemes are examined in terms of input tracking capability, level of sway reduction and robustness to parameters uncertainty. A comparative assessment of the hybrid controllers to the system performance is presented and discussed.