Research on an Active Heave Compensation System for Remotely Operated Vehicle
ABSTRACT Heave motion of supporting ships deeply affect the normally operating, safely launching and recovering of Remotely Operated Vehicles when the sea state becomes rough. A heave compensation system can uncouple the heave movement between supporting ships and Remotely Operated Vehicles. An active heave compensation system which includes a measurement unit, a controlling unit and a hydraulic winch is researched in the paper. For attaining the efficiency of the active heave compensation system, simulating model is built and the computer simulation is achieved. The computer simulation proved the effectiveness of the active heave compensation system. For verifying the correctness of the simulating model and acquiring the efficiency of the real active heave compensation system, an active heave compensation experiment system which includes a heave motion generating unit, a load and an active heave compensation system is built. The movement which created by the heave motion generating unit simulates the heave motion of the supporting ship. The load is a substitute of the underwater vehicle. The result of the active heave compensation experiment certifies the correctness of the simulating model and the effectiveness of the active heave compensation system.
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ABSTRACT: A passive heave compensator is designed to enhance the operation safety of a 4.5 km remotely operated vehicle (ROV). This paper proposes a novel idea of designing a compensator with relatively low natural period to optimize gas volume and while adding a special device to remove the problem of ineffectiveness and resonance in long seas. Numerical simulations are done based on serious dynamic model of the whole system, including the compensator, the umbilical tether and the vehicle, solved by the fourth-order Runge-Kutta scheme. The compensator provides great attenuation of motion and tension in most sea states. As the working depth increases, the system natural period decreases, resulting in the occurrence of risk of resonance. By regulating the system damping, the compensator can be effective in these situations. Key wordsheave compensation–spring isolation–nonlinear dynamics–damping controlJournal of Shanghai Jiaotong University (Science) 01/2011; 16(1):40-44.