Fault-tolerant control of dynamic positioning vessel after thruster failures using disturbance decoupling methods

This paper presents a method for on-line control reconfiguration of fault-tolerant control to dynamic positioning (DP) vessel using disturbance decoupling methods after the occurrence of thruster failures. First, a suitable linear state-space model of DP vessel is derived which consists of motions in 3 DOF. Then control reconfiguration after thruster failures is finished which combines with faulty DP vessel model and reconfiguration block. The paper shows that this reconfiguration problem is equivalent to a disturbance decoupling problem. To solve it, this paper follows the geometric approach. The resulting reconfiguration block generates suitable inputs for the faulty vessel based on the output of the nominal controllers. At last, the feasible and effective of this method are demonstrated by a simulation of a DP vessel.