Disturbance rejection by acceleration feedforward: Application to dynamic positioning

Abstract

This paper addresses environmental disturbance rejection in dynamic systems by means of acceleration feedforward. A feedforward structure calculates the environmental force and magnitude by comparing the filtered acceleration measurement with the acceleration due to actuation and known forces. Direct compensation of the environment by feedforward will alleviate the position and velocity feedback terms. The presented scheme compensates environmental disturbances affecting the system in addition to model uncertainties. First, the design is used for a mechanical system and illustrated for an inverted pendulum. Then, the main application, being a dynamic positioning system affected by ice forces in an Arctic operation, is controlled by acceleration feedforward to give enhanced performance.