Application of Data Driven Control to Dynamic Positioning

The paper presents the results of applying a data driven model free control strategy, built upon unfalsified control techniques, to the problem of Dynamic Positioning (DP) of marine vessels subjected to environmental forces. The unfalsified control technique builds on the construction of a bank of controllers for a given plant, in which there exists at least one controller that meets desired performance specification and a falsification unit. The latter is implemented using a cost function that directly evaluates the performance of the controllers (in and out of the feedback loop) using measured input and output data. At each sampling time, the performance of the controllers is assessed and the controllers that do not meet the pre-defined performance specification criteria will be falsified and removed from the bank of the controllers after which an active controller will be selected among the unfalsified ones. The proposed adaptive structure of the controller enables the DP system to operate under different environmental conditions by automatically falsifying controllers that do not meet the performance criteria, and eventually selecting the controller that provides the requested performance, leaving the human decision to the top of the hierarchical DP control structure. Numerical simulations show how a destabilizing controller is detected and replaced by one that is able to meet the designed performance specification. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.