Final colloquium Theodoulos Kapnisis

07 October 2022 12:00 till 12:45 - Location: commissiekamer 3, aula - By: DCSC | Add to my calendar

"Modelling and control of experimental scale hydrofoil craft"

Hydrofoil crafts with fully submerged foils can provide fast and economical waterway trans-port. However, their operation requires reliable onboard control systems to ensure the safety and comfort of their passengers, especially in rough sea conditions. This thesis project is focused on the dynamical modelling and the design of motion control systems for an exper-imental scale hydrofoil craft that is available at TU Delft, namely Hydrofoil Education and Research Platform (HEARP).

The development of the dynamical model of HEARP is done by taking inspiration from the dynamics of marine crafts and aircraft, and by relying on different assumptions to obtain a simple and low-order model. The resulting model is a linearized state-space model with three degrees of freedom (DOF), namely heave, roll and pitch, and includes the influence of regular waves. Because of inaccurate available data for the mass properties of HEARP, variations of the system parameters due to nonlinearities, and changes in the operating conditions, different uncertainties are assigned to most system parameters.

The use of multivariable feedback control methods for the motion control of hydrofoil crafts is limited, so this work is focused on exploiting such methods to improve the performance and robustness of such systems. The representation of the perturbed system using real parametric uncertainties is proved to be computationally expensive for the control design. Thus the perturbed systems is approximated by complex (dynamic) perturbations. A signal-based H∞ optimal controller is designed using the nominal system, and a µ-synthesis optimal robust controller is designed using the approximated perturbed system.

The performance and robustness of the two proposed controllers are evaluated in both fre-quency and in the time domain through simulations. From the results, is concluded that both controllers offer high-performance system responses for both reference tracking and dis-turbance rejection of incident waves. Furthermore, by comparing the two controllers, it is observed that the µ-synthesis controller shows superior robustness for the modelled uncer-tainty. In contrast, the H∞ controller has a slightly better performance when considering the perturbed systems with the real parametric uncertainty. The results of this thesis project can be used in the future to experimentally validate the accuracy of the proposed dynamical model and the performance of the designed controllers.

Dr. D. Boskos, Dr. O. Nejadseyfi and I. Akkerman

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