Clementina Rueda-German

Disturbances in dynamical systems pose a major challenge for parameter identification, particularly in the presence of unknown initial conditions and uncertain external influences. To address this issue, this paper proposes an algebraic parameter estimation methodology that incorporates fractional-order calculus in the Laplace domain for controlled linear engineering systems. The proposed approach eliminates the influence of unknown initial conditions and considers external disturbances that admit a local polynomial representation through Taylor series expansions over sufficiently small time intervals, while avoiding explicit numerical differentiation in the time domain. The manuscript includes analytical, numerical, and experimental validations to highlight the benefits of incorporating fractional-order differentiation in the derivation of algebraic estimators for online parameter estimation. The method is experimentally validated on two linear differentially flat electrical circuits, whose flat representations enable the proposed algebraic formulation under distinct disturbance signals. The results demonstrate that the fractional differentiation order acts as an additional tuning parameter, and that appropriately selected fractional orders can improve estimation accuracy, yielding parameter estimates consistently closer to their true values when compared with the conventional integer-order algebraic formulation.

Marine robotics has become central to contemporary ocean exploration and conservation, providing unprecedented access, precision, and continuity in the observation of marine environments. This chapter examines the capabilities and emerging roles of autonomous underwater vehicles, remotely operated systems, and hybrid robotic platforms in mapping seafloor structures, monitoring ecological dynamics, and supporting restoration initiatives in sensitive habitats. It evaluates recent advances in perception, navigation, and machine-driven decision-making that enable robots to operate safely and adaptively in complex, uncertain, and data-scarce marine settings. Furthermore, the chapter discusses the integration of robotics with oceanographic sensors, artificial intelligence, and real-time communication infrastructures to enhance environmental intelligence. Ethical considerations, operational challenges, and future research pathways are also addressed to guide the responsible deployment of robotic technologies for long-term marine sustainability.

The accurate estimation of parameters in dynamical systems stands for an open key research issue in modeling, control, and fault diagnosis. The presence of noise in input and output signals poses a serious challenge for accurate real-time dynamical system parameter estimation. This paper proposes a new robust algebraic parameter estimation methodology for integer-order dynamical systems that explicitly incorporates the signal filtering dynamics within the estimator structure and enhances noise attenuation through fractional differentiation in frequency domain. The introduced estimation methodology is valid for Liouville-type fractional derivatives and can be applied to estimate online the parameters of differentially flat, oscillating or vibrating systems of multiple degrees of freedom. The parametric estimation can be thus implemented for a wide class of oscillating or vibrating, nth-order dynamical systems under noise influence in measurement and control signals. Positive values are considered for the inertia, stiffness, and viscous damping parameters of vibrating systems. Parameter identification can be also used for development of actuators and control technology. In this sense, validation of the algebraic parameter estimation is performed to identify parameters of a differentially flat, permanent-magnet direct-current motor actuator. Parameter estimation for both open-loop and closed-loop control scenarios using experimental data is examined. Experimental results demonstrate that the new parameter estimation methodology combining signal filtering dynamics and fractional calculus outperforms other conventional methods under presence of significant noise in measurements.

In this article, the model of a family of underwater vehicle multi-manipulator systems (UVMMS) is obtained by considering all its elements as parts of a unique system, the model includes the forces produced on the manipulators by the movement of the vehicle, as well as the reaction forces on the vehicle produced by the movement of the manipulators. The modeling process is completed using the Newton–Euler approach through the mobile arborescent kinematic chain. This work also presents different approaches to the use of numerical implementations of the proposed model, and simulation results are included to demonstrate that the model is capable to represent the interaction between the vehicle and the manipulators. The proposed model and simulations are important because they allow the design of control strategies that consider all the elements of the system instead of neglecting the interaction forces or considering the vehicle and the arms as uncoupled elements.

Synchrony plays a major role in the interconnection process between local electric power generation systems and the electrical grid. Grid phase disturbances prevent the generation system from maintaining synchrony. Therefore, an efficient phase tracking method is necessary in order to detect phase jumps and abrupt changes in amplitude. In this paper, we propose a software-designed method to strengthen phase tracking based on the wrap process of a second-level Phase Locked Loop (PLL). The term ‘wrap’ means establishing the phase values of the reference signal in intervals of π to match it with the values obtained from the PLL output (sync pulse). To quantify phase error, a mathematical transformation of the time domain to the frequency domain is implemented. The validity of the proposed wrap function is verified using electrical disturbances. La sincronía es primordial para la interconexión de sistemas locales de generación de energía con el sistema eléctrico. Las perturbaciones en fase evitan que el sistema de generación mantenga la sincronía. Por lo tanto, un método eficiente de seguimiento de fase es necesario para detectar saltos en la misma y cambios abruptos en amplitud. En este trabajo se propone un método para fortalecer el seguimiento de fase basado en el proceso de envoltura de fase de un PLL (Phase Locked Loop) de segundo grado diseñado por software. El término ‘envoltura’ (wrap) se refiere a establecer los valores de fase de la señal de referencia en intervalos de π para que coincida con los valores obtenidos de la señal de salida del PLL (pulso de sincronía). Una técnica de transformación matemática del dominio del tiempo al dominio de la frecuencia es implementada con el fin de cuantificar el error de fase. La validez de la función de envoltura propuesta es verificada usando perturbaciones eléctricas.