Nonlinear Dynamics of Crane Operation at Sea

The object of this project is to develop an automatic shipboard container loading system combining a nonlinear automatic crane control with a nonlinear lighter-tracking system. The integrated system will move containers to their destinations quickly and safely, during offshore loading operations. The control system will remove pendulation ("sway") induced by crane platform motion, and is based on an existing Anti-Sway Control (ASC) system developed by Wagner for shore-based cranes. ASC employs a nonlinear, nearly time-optimal, double-pulse control law that meets arbitrary velocity or load position demands with zero sway. The shipboard anti-sway control will be integrated with the T-ACS Rider-Block Tagline System (RBTS) to control sway in 3 dimensions. The lighter-tracking component is based on an existing Moored-Ship Motion Determination (MSMD) system also developed by Wagner. The MSMD system is a sensor system developed specifically for tracking the motion of vessels restrained by warps to loading platforms. MSMD employs an extended Kalman filter (EKF) and a nonlinear motion model to fuse multiple-sensor data into relative position, orientation, and rate of movement of the lighter, in six degrees of freedom. This technology will