Abstract
A robotized dry test rig in six degrees of freedom, for emulating the influence of hydrodynamic forces on and the resulting motion response of different types of point absorbing wave energy converters has been developed at Uppsala University. In the past we have investigated and shown that the dry test rig works with both force and position control methods.
In this article we further examine the position control method, as we have not been able to use it for rougher wave movements. This is due to the fact that there has been a control lag in the system which contributed to the system becoming unbalanced in some emulation scenarios. A solution for an updated position control method, with significantly reduced control lag, is demonstrated in robot simulations and compared with both hydrodynamic model simulations and physical robot experiments for two buoy sizes in regular waves.
The results show a clear positive solution for avoiding control lag problems, making the position control method fully possible to use in the field. Future work is to implement the updated method on the physical robot test rig.
