Dynamic compensation system [ships]

A dynamic compensation system (DC-system) has been developed. It is used as an extension of the KaMeWa polar joystick system, where the horizontal motions of a ship are controlled by main propellers, rudders and bow thrusters. It acts like a compensator for wind and current disturbances, allowing the joystick operator to run the ship in almost all weather conditions as if it were calm. It generates additional commands, which are superimposed on the commands from the operator. It uses measurements of speed and heading, and wind speed and direction. Position measurements can also be processed. A nonlinear Kalman filter and a nonlinear controller is the kernel of the DC-system, which also includes a wind influence model and a separation model for dividing the measured speeds into a ship's speed part and a water current part. Entering alarm limits is very simple. The parameters for a specific ship are determined with straightforward step response tests.<>