Multi-objective optimal control for energy extraction and lifetime maximisation in dielectric elastomer wave energy converters

Hoffmann, Matthias K.; Moretti, Giacomo; Rizzello, Gianluca; Flaßkamp, Kathrin

doi:10.1016/j.ifacol.2022.09.152

Cited by 3 publications

(12 citation statements)

References 10 publications

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“…In the following, a dynamic model of the WEC is briefly summarized, based on the work previously published in [16,20]. The model is built upon the assumption that the flap pitch oscillation is small (

θ ≪ 1 rad

), and it describes the dynamics of the device in terms of equations of motion of the pitching flap coupled with the wave field (see Figure 2A).…”

Section: Pitching Flap Wave Energy Converter With Dielectric Elastome...mentioning

confidence: 99%

“…Heuristic control strategies for DEG power take‐off systems are based on a pre‐fixed bang‐bang structure [22]. To the best of the authors' knowledge, our previous work [16] was the first on multiobjective optimization of DEG‐WEC systems. The energy cost function considers the effect of electrical losses within the dielectric elastomer, unlike in [26], and we include an objective for lifetime optimization.…”

Section: Introductionmentioning

confidence: 99%

“…The energy cost function considers the effect of electrical losses within the dielectric elastomer, unlike in [26], and we include an objective for lifetime optimization. Based on a nonlinear system model, in [16], we computed Pareto‐optimal trade‐offs which allow for a reduction of damage by more than 50% while only losing 1% of energy compared to a control that only aims at maximizing the power. Here, excitation had been reduced to monochromatic waves and fictitiously long prediction horizons were assumed.…”

Section: Introductionmentioning

confidence: 99%

“…MPC can be used to overcome the need for long‐term predictions of wave excitation, [9]. In [15], we give a detailed study on the MPC prediction horizon needed to obtain solutions acceptably close to the optimal control ground truth. When considering multiple objectives, decision making needs to be automated within the MPC loop.…”

Section: Introductionmentioning

confidence: 99%

“…For wind energy harvesting, this idea is described in detail in [25]. A simple switching heuristic has been presented in [15], already.…”

Section: Introductionmentioning

confidence: 99%

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Optimal operation of dielectric elastomer wave energy converters under harmonic and stochastic excitation

et al. 2023

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Dielectric elastomers are a promising technology for wave energy harvesting. An optimal system operation can allow maximizing the extracted energy and, simultaneously, reducing wear that would lead to a reduction in the wave harvester lifetime. We pursue a model‐based optimization approach to identify optimal controls for wave energy harvesters based on dielectric elastomers. First, a direct method is used for time‐discretization of the dielectric elastomer wave energy harvester in the optimal control problem. The two conflicting objectives are considered in a multiobjective optimization framework. Considering a periodic, sinusoidal wave excitation, the optimal solution shows turnpike properties for the optimal periodic mode of operation. However, since real wave motion is neither monochromatic nor predictable on longer time horizons, further extensions are pursued. First, we introduce a stochastic wave excitation. Second, an iterative model‐predictive control scheme is designed. Due to multiple objectives, the control scheme has to include an automated adaption of the corresponding priorities. Here, we propose and evaluate a heuristic rule‐based adaption in order to maintain the damage below target levels. The approach presented here might be used in the future to guarantee for autonomous operation of farms of wave energy harvesters.

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θ ≪ 1 rad

), and it describes the dynamics of the device in terms of equations of motion of the pitching flap coupled with the wave field (see Figure 2A).…”

Section: Pitching Flap Wave Energy Converter With Dielectric Elastome...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…For wind energy harvesting, this idea is described in detail in [25]. A simple switching heuristic has been presented in [15], already.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optimal operation of dielectric elastomer wave energy converters under harmonic and stochastic excitation

et al. 2023

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Multi-Objective Model-Predictive Control for Dielectric Elastomer Wave Harvesters

Hoffmann,

Heib,

Rizzello

et al. 2023

IFAC-PapersOnLine

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Possibilities of Artificial Muscles Using Dielectric Elastomers and their Applications

Chiba

Waki²,

Takeshita

et al. 2023

AMR

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The recent developments in dielectric elastomers (DE) are spectacular. Currently, a DE as an actuator, 0.15 g of acrylic sandwiching SWCNT electrodes, is capable of lifting a weight of 8 kg by more than 1 mm at a speed of 88 msec. In the near future, DE motors could be used to drive electric vehicles. Moreover, the DE can be used as a high-efficiency sensor with the same structure. With a diameter of 20 mm and a thickness of 0.5 mm, it can accurately measure pressure from several kg to 150 kg. In addition, reversing this DE actuator (DEA) movement also enables high-efficiency power generation. In other words, when the DEA is stretched or pushed, it generates electric power. Single wall nanotubes (SWCNTs) were used as an electrode, and an acrylic DE power generation cartridge with a diameter of 80 mm was used. When the center of the DE power generation cartridge is pushed by about 15 mm, a power of 33.6 mJ is generated. Using these two DE cartridges, it was possible to charge a secondary battery through a DC converter. In addition to this power generator, practical research and development of power generation using wave power, wind power, waste heat, and fluids (ocean currents, water currents, etc.) is progressing. In this paper, we have described state-of-the-art DEAs, DE generators (including the case that the power generated locally by microgenerators are consumed locally), and DE sensors and explained their usefulness.

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Multi-objective optimal control for energy extraction and lifetime maximisation in dielectric elastomer wave energy converters

Cited by 3 publications

References 10 publications

Optimal operation of dielectric elastomer wave energy converters under harmonic and stochastic excitation

Optimal operation of dielectric elastomer wave energy converters under harmonic and stochastic excitation

Multi-Objective Model-Predictive Control for Dielectric Elastomer Wave Harvesters

Possibilities of Artificial Muscles Using Dielectric Elastomers and their Applications

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