Abstract: Apparatus and method for estimating and for controlling a rotary speed of a drill bit disposed at a distal end of a drillstring. One method comprises identifying one or more parameters of a lumped one-degree-of-freedom (1DOF) model which accounted for one or more well parameters and drillstring parameters, linearizing the lumped 1DOF model for a desired state, wherein a discrete state space model and an associated output are defined using a discrete equation, calculating an estimated rotary speed of the drill bit by applying a predict step and an update step to the linearized lumped 1DOF model, providing a controller input representing a difference between a desired rotary speed and the estimated rotary speed of the drill bit to a polynomial controller designed based on the lumped 1DOF model, and adjusting the rotary speed of the drill bit utilizing the polynomial controller based on the controller input.

Abstract: This naval platform (1) of the type including at least one hull (2) equipped with steerable thrusters (3, 4, 5, 6) distributed on the latter and means (7, 8, 9, 10, 11) for controlling the orientation and the actuation of the latter, is characterized in that the control means comprise means (12) for illustrating at least one portion of the surface of the water around the naval platform (13) in proximity to the latter, associated with the means (14, 15, 16, 17, 18, 19, 20, 21) for controlling at least one portion of the steerable thrusters (3, 4, 5, 6) for generating and directing a waterflow towards this portion of the surface.

Abstract: This naval platform (1) of the type including at least one hull (2) equipped with steerable thrusters (3, 4, 5, 6) distributed on the latter and means (7, 8, 9, 10, 11) for controlling the orientation and the actuation of the latter, is characterized in that the control means comprise means (12) for illustrating at least one portion of the surface of the water around the naval platform (13) in proximity to the latter, associated with the means (14, 15, 16, 17, 18, 19, 20, 21) for controlling at least one portion of the steerable thrusters (3, 4, 5, 6) for generating and directing a waterflow towards this portion of the surface.