  This contribution deals with multi-objective model-predictive control (MPC)
of a wave energy converter (WEC) device concept, which can harvest energy from
sea waves using a dielectric elastomer generator (DEG) power take-off system.
We aim to maximise the extracted energy through control while minimising the
accumulated damage to the DEG. With reference to system operation in stochastic
waves, we first generate ground truth solutions by solving an optimal control
problem, and we analyse the MPC performance to determine a prediction horizon
that trades off accuracy and efficiency for computation. Fixed weights in the
MPC scheme can produce unpredictable costs for variable sea condition, meaning
the average rate of cost accumulation can vary vastly. To steer this cost
growth, we propose a heuristic to adapt the algorithm by changing the weighting
of the cost functions using for fulfilling the long-time goal of accumulating a
small enough damage in a fixed time. A simulated case-study is presented in
order to evaluate the performance of the proposed MPC framework and the
weight-adaptation algorithm. The proposed heuristic proves to be able to limit
the amount of accumulated damage while remaining close to (or even improving)
the energy yield obtained with a comparable fixed-weight MPC.

Systems and Control;Systems and Control