MacGregor’s Motion-Compensated Pile Gripper Concept Successfully Tested in Motion Lab

Between October 2020 and April 2023, the Norwegian Motion Laboratory (Motion Lab) at the University of Agder has been used to catalyze the proof-of-concept testing of a motion-compensated pile gripper to install monopiles for fixed offshore wind turbines. See this video and news articles: [1, 2, 3], for more information about the process. The test was carried out in collaboration with MacGregor Norway AS under the Research Council of Norway’s MAROFF-2 program (project no. 309895). 

Test Setup

MacGregor has designed a down-scale test setup, as shown in the picture above, and installed it on the EM-1500 Stewart platform in Motion-Lab. The scaled model has the possibility for two 6-Degree-of-Freedom (DOF) loadcells to analyze and monitor the loads, with one wire force loadcell being permanently installed.  The feedback of the position of the monopile is measured by a Kongsberg Motion Reference Unit (MRU) installed inside the monopile and further verified with the Motion-Lab Qualisys motion capture system [4].

Proof-of-Concept Testing

Tests were conducted with and without water, and to simulate firm contact with the seabed by establishing a 3-DoF connection between the monopole and a floor of the water basin. The video links below demonstrate the performance of MacGregor’s innovative concept by showing the behavior of the monopile with and without motion compensation.