Search results for "Active heave compensation"
showing 8 items of 8 documents
Performance Improvement of a Hydraulic Active/Passive Heave Compensation Winch Using Semi Secondary Motor Control: Experimental and Numerical Verific…
2020
In this paper, a newly developed controller for active heave compensated offshore cranes is compared with state-of-the-art control methods. The comparison is divided into a numerical part on stability margins as well as operational windows and an experimental validation of the expected performance improvement based on a full-scale testing on site with a crane rated to 250 metric tons. Such a crane represents the typical target for the new control method using a combination of active and passive hydraulic actuation on the main winch. The active hydraulic actuation is a hydrostatic transmission with variable-displacement pumps and variable-displacement motors. The new controller employs feedf…
Testing of wireless sensor performance in Vessel-to-Vessel Motion Compensation
2016
Relative Vessel-to-Vessel Motion Compensation (VVMC) between two floating vessels can be considered an extension of existing Active Heave Compensation (AHC), which is current state-of-the-art in the offshore industry. In this paper, the experimental results from a small-scale experimental setup of a VVMC scenario are presented. The work focuses on the kinematics related to VVMC, sensor accuracy of Motion Reference Units (MRUs), and the communication delay related to wireless transmission of MRU data between two floating vessels. The accuracies of the MRU sensors are good and verified to be less than 5% of the heave amplitude. The wireless communication link had a typical time-delay of 8ms. …
A Control Algorithm for Active/Passive Hydraulic Winches Used in Active Heave Compensation
2019
Abstract The most common active heave compensated offshore cranes have hydraulic winch systems. This paper investigates an active/passive hydraulic winch system with variable-displacement motors and variable-displacement pumps. The paper addresses the challenges when the active motors are set with a low displacement. The active motor displacement is shown to have significant impact on the dynamics of the closed loop hydraulic system. The classical control strategy for this type of system do not address these challenges and will in certain situations have significantly reduced performance. Therefor, a new control method is presented that utilize the variable displacement of the pumps and mot…
Hardware-in-the-loop implementation for an active heave compensated drawworks
2012
Published version of an article published in the journal: Central European Journal of Engineering. Also available from the publisher at: http://dx.doi.org/10.2478/s13531-011-0062-1 This paper presents the setup and running of a hardware-in-loop (HIL) simulation for an active heave compensated (AHC) draw-works. A simulation model of the draw-works is executed on a PC to simulate the AHC draw-works with a physical PLC. The PLC (ET200S) is configured with a controller architecture that regulates the motor angular displacement and velocity through actuation of the servo valves. Furthermore, a graphical user interface is developed for operation of the AHC system. The HIL test allowed tuning of t…
The Effect of Friction in Passive and Active Heave Compensators of Crown Block Mounted Compensators
2012
Abstract This paper studies the effects of friction model during passive and active heave compensation of offshore drilling equipment. The main purpose of heave compensation while drilling from vessels or semi-submersible platforms is to maintain the drilling operation unaffected by the wave induced motion. The investigated system is of an existing crown mounted compensator. A model of the system is developed which includes mechanics, hydraulics and pneumatics. The passive heave compensation scheme is described including force equalising hydraulic cylinders. In this paper the detrimental effect of friction on the heave compensation performance in both passive and active heave compensation i…
Modeling, simulation and design optimization of a hoisting rig active heave compensation system
2012
Published version of an article in the journal: International Journal of Machine Learning and Cybernetics. Also available from the publisher at: http://dx.doi.org/10.1007/s13042-012-0076-x The objective of this paper is to present an approach in developing a virtual active heave compensation system for a draw-works on a hoisting rig. A virtual system enables quicker overall product development time of a physical system as well as flexibility in optimizing the design parameters. Development of the virtual system started with the modelling of the draw-works and hoisting rig dynamics. Simulations of this model were run in two operational modes while subject to a sinusoidal wave: heave compensa…
Real-time 6-DOF Vessel-to-Vessel Motion Compensation using laser tracker
2017
The industry state-of-the-art offshore motion compensation is today carried out by offshore cranes equipped with Active Heave Compensation (AHC) systems, meaning that a hanging load is positioned at a certain height above the seafloor, even though the floating vessel carrying both the crane and the load is moving due to wave disturbances. Lately, there has been an increased interest among the industry also to compensate for the movement of a secondary vessel, which indicates that a more detailed investigation of the Vessel-to-Vessel Motion Compensation (VVMC) problem is required. The primary motivation for such compensation technique is influenced by the demand for load transfer between shi…
Active heave compensation of floating wind turbine installation using a catamaran construction vessel
2021
Abstract The application of floating wind turbines is limited by the high cost that increases with the water depth. Offshore installation and maintenance continue to consume a high percentage of the project budget. To improve the installation efficiency of the floating offshore wind turbine, a novel concept is proposed by the SFI MOVE project. Several wind turbine superstructure components are preassembled onshore and carried to the installation site by a catamaran construction vessel. Each assembly can then be installed using only one lift, and the concept is less sensitive to weather conditions. In this paper, a control algorithm of the proposed hydraulic active heave compensator system i…