Modelling, Design and Robust Control of a Remotely Operated Underwater Vehicle

Abstract

Underwater remotely operated vehicles (ROVs) play an important role in a number of shallow and deepwater missions for marine science, oil and gas extraction, exploration and salvage. In these applications, the motions of the ROV are guided either by a human pilot on a surface support vessel through an umbilical cord providing power and telemetry, or by an automatic pilot. In the case of automatic control, ROV state feedback is provided by acoustic and inertial sensors and this state information, along with a controller strategy, is used to perform several tasks such as station-keeping and autoimmersion/heading, among others. In this paper, the modelling, design and control of the Kaxan ROV is presented: i) The complete six degrees of freedom, non linear hydrodynamic model with its parameters, ii) the Kaxan hardware/software architecture, iii) numerical simulations in Matlab/Simulink platform of a model-free second order sliding mode control along with ocean currents as disturbances and thruster dynamics, iv) a virtual environment to visualize the motion of the Kaxan ROV and v) experimental results of a one degree of freedom underwater system.

Development of the mathematical modeling method for dynamics of the flexible tether as an element of the underwater complex

“…Afterwards, the running end does not move for 10 seconds, then at the moment of time t 4 it starts moving forward at the velocity of 1 m/s. In such a way, it moves for 25 s and stops at the moment of time t 6 . Fig.…”

“…The main reason is that it causes the MMO numerical model to be very complicated and difficult to solve. Thus, the ROV mathematical models presented in [5,6] don't include the cable influence and are useful for studying only slow ROV motions or positioning without current.…”

Velocity Controller for a Class of Vehicles

“…The equations (1) and (2) can be applied for ocean or marine vehicles as well as for airships during indoor experiments. Such examples can be found: (1) for underwater vehicles in [12,17], (2) for surface vessels in [7,18] or hovercrafts in [13,21], (3) for indoor airships in [23,31]. The control strategy is based on transformed equations of motion with the identity inertia matrix.…”

“…Fully actuated vehicles are often considered in the literature, e.g. in for underwater vehicle [9,12], surface vehicles [26,28], hovercrafts [13,25] or airships [20,29]. The main difference between our velocity tracking controller and the aforementioned approaches relies on that we include the vehicle dynamics directly into the velocity control gain matrix.…”

Devising a method for maintaining manageability at multidimensional automated control of tethered underwater vehicle

“…Results of the proposed SAC performance are shown for the one-dimensional motion in order to simplify analysis of the effect of propulsion device dynamics on the overall behavior of the system. Sliding mode control method is applied in [6] for the synthesis of SAC for spatial motion of ROV. The effectiveness of SAC is confirmed by simulating the ROV with four controlled degrees of freedom.…”