Robust energy-maximising control of wave energy systems under input uncertainty

Motivated by the ubiquitous presence of input uncertainty in the wave energy control problem, we propose, in this paper, a robust energy-maximising framework which explicitly considers potential wave excitation force deviations in the computation of the optimal control law, while systematically respecting state and input constraints. In particular, this is achieved by a suitable moment-based characterisation for the input uncertainty, taking into consideration an appropriate convex uncertainty set. The concept of moments is combined with well-known robust optimisation principles, by proposing a worst-case performance approach. We show that this novel moment-based robust optimal control framework always admits a unique global energy-maximising solution, hence leading to a computationally efficient robust solution. The performance of the proposed controller is illustrated by means of a case study, considering a heaving point absorber WEC.