arXiv subjects

Manuel C. R. M. Fernandes

Publications and source records attributed to Manuel C. R. M. Fernandes.

4 recordsLinked to original sources

arXiv2026

A Computationally Tractable Path-Planning Method for Airborne Wind Energy Systems

Airborne Wind Energy Systems (AWES) have emerged as a promising renewable energy technology that exploits stronger, more consistent high-altitude winds via tethered airborne devices. Among the various concepts, crosswind systems, where efficient flight control is essential to maximise energy output, offer significant potential. This paper addresses the problem of reference selection for crosswind flight control, focusing on the design of power-maximising geometric flight paths for the reel-out phase of Groundgen systems. To overcome the computational challenges associated with optimal control approaches, a computationally tractable framework is proposed in which a path-planning problem is formulated as a nonlinear program. The method optimises the parameters of a Lissajous curve to maximise the average power production over the reel-out phase, while incorporating curvature constraints. The proposed approach provides an efficient alternative to existing optimal control and learning-based methods.

math.OC↗

arXiv2026

Geometric Look-Angle Shaping Strategy for Enclosed Inspection

This paper introduces inspection through GLASS, a Geometric Look-Angle Shaping Strategy for enclosed regions using unmanned aerial vehicles. In doing so, the vehicles guidance command is constructed through a bounded, geometry-consistent shaping of the look angle relative to a desired standoff path. By embedding a smooth, hyperbolic-tangent-type shaping function within a polar geometric framework, GLASS ensures global existence of the guidance dynamics. It avoids the far-field limitations inherent to conventional formulations. Lyapunov stability analysis establishes asymptotic convergence to a prescribed inspection standoff under explicit curvature feasibility conditions, along with analytical settling-time characteristics. The proposed strategy incorporates maximum turn-rate constraints without inducing singularities throughout the workspace. High-fidelity six-degree-of-freedom quadrotor simulations demonstrate the effectiveness of GLASS in representative enclosed inspection scenarios, highlighting a practically viable guidance framework for autonomous enclosed inspection missions.

cs.RO↗

arXiv2025

Variable L0 Guidance Strategy: Enlarged Operational Envelope and Path-Following

This paper presents a geometric and theoretical study of an exponentially varying look-ahead parameter for UAV path-following guidance. Conventional guidance laws with a fixed look-ahead distance often drive the vehicle into turn-rate saturation when the heading or cross-track error is large, leading to constrained maneuvers and higher control effort. The proposed variable L0 strategy reshapes the look-ahead profile so that the guidance command adapts to the evolving tracking error geometry. A detailed investigation shows that this adaptation significantly enlarges the region in which the commanded turn rate remains unsaturated, allowing the vehicle to operate smoothly over a broader range of error conditions. For representative settings, the unsaturated operational envelope increases by more than 70% relative to the constant L0 formulation. These geometric insights translate to smoother trajectories, earlier recovery from saturation, and reduced control demand. Simulation studies on straight-line and elliptical paths demonstrate the merits of the variable look-ahead strategy, highlighting its control-efficient and reliable path-following performance.

eess.SY↗

arXiv2024

Automatic Circular Take-off and Landing of Tethered Motorized Aircraft

We consider a motorized aircraft tethered to a central anchorage point in a configuration similar to a control line model airplane. For this system, we address the problem of automatic take-off and landing (ATOL) with a circular path, whose center and radius are defined by the anchorage point and the tether length, respectively. We propose a hierarchical control architecture for ATOL and discuss the controllers designed for each control layer and for each of the flight phases. Simulation results are reported, showing the viability of the approach, but also showing the limitations on the maximum altitude attainable with a fixed-tether length. The tethered aircraft and the proposed ATOL control architecture are to be used in an Airborne Wind Energy System.

math.OC↗