Robust Tool Point Control for Offshore Knuckle Boom Crane

This paper considers the design of an H ∞ controller for tool point control of a hydraulically actuated knuckle boom crane. The paper describes the modelling of the crane's mechanical and hydraulic systems and a disturbance model. These are linearised and combined in a state-space model used for the controller design. The controller synthesis problem is to design (if possible) an admissible controller that solves the problem of robust regulation against step inputs with an H ∞ constraint based on the internal model principle. Simulation results are given to show the effectiveness of the method.