Ti. Fossen et A. Grovlen, NONLINEAR OUTPUT-FEEDBACK CONTROL OF DYNAMICALLY POSITIONED SHIPS USING VECTORIAL OBSERVER BACKSTEPPING, IEEE transactions on control systems technology, 6(1), 1998, pp. 121-128
Dynamic positioning (DP) systems for ships are usually designed under
the assumption that the kinematic equations can be linearized about a
constant yaw angle such that linear theory and gain scheduling techniq
ues can be applied. This paper proposes a globally exponentially stabl
e (GES) nonlinear observer is included in the design such that only po
sition measurements are required. GES is proven by applying the backst
epping design methodology and Lyapunov stability theory. The control l
aw is simulated on two thruster-controlled ships.