Parameter identification of marine risers using Kalman-like observers

• A model of a marine riser in state space representation is presented.
• A model of a marine riser in Liénard representation is determined.
• Kalman-like observers are designed to identify the structural parameters of a riser.

The goal of this paper is to present a nonlinear approach to identify the structural parameters of a vertical riser. To carry out this task, Kalman-like observers are proposed so that they can deal with the nonlinear behavior that is exhibited in the restoring force of a riser and the noise of the measurement signals that are used to perform the identification. The observers are designed from a spatial discretization of a nonlinear model with distributed parameters that is described by a system of quasi-linear partial differential equations. Some results from numerical simulations—showing the feasibility of the proposed approach—are presented.