Modeling and optimal control design of shipboard crane

A linearized dynamical model of shipboard crane with the Maryland Rigging is derived by using Lagrange's equations. Based on the linearized model, numerical resonant frequencies of Maryland Rigging are obtained and verified for complete nonlinear model. One disturbance, the ship roll motion angle, and three control authorities, changing the length of pulley cable, pulley-brake mechanism control option and load control torque are included in the linearized model for analysis. Controllability and observability are confirmed for each control variable. An active control law to cancel the effect of ship roll motion on load pendulation is achieved by changing the cable length of the pulley and proved to be valid for small ship roll motion. Also, a controller based on linear quadratic regulator (LQR) is designed to reduce pendulation.