Έρευνα | Δρ. Ευάγγελος Βλάχος

Semantically-Informed Predictive Control for Autonomous UAV Connectivity in Urban Environments

Mon, 24 Aug 2026 00:00:00 +0000

Key Contributions

An Effective Capacity metric that extends the radio map paradigm by weighting raw throughput with a material-dependent reliability coefficient, decoupling signal strength from link stability and exposing permeable vegetation corridors that signal-strength planners overlook.
A two-layer planner comprising (i) a Semantically-Informed RRT backbone augmented with material-dependent reliability and capacity acceptance checks that prune expansion through multipath zones, and (ii) a gradient-based trajectory optimizer that deforms the path by balancing signal-seeking and reliability-seeking forces derived from the product-rule decomposition of ∇C_eff.
Hardware validation of the material ambiguity premise via characterization with a TI IWR6843AOP 60 GHz FMCW radar, confirming that radar alone cannot distinguish concrete from vegetation.

Hardware-Aware SE(3) Control Barrier Functions for Counter-UAS Interceptors with Directed Energy Payloads

Wed, 17 Jun 2026 00:00:00 +0000

Simulation Demo

The animation below compares two methods on the SE(3) CBF scenario: the unfiltered controller (red) and the proposed ADMM-CBF safety filter (blue), which maintains FoV pointing throughout the pursuit maneuver.

Key Contributions

A hardware-aware CBF safety filter on the SE(3) manifold that provides formal FoV pointing guarantees for directed-energy payloads under aggressive pursuit dynamics.
Formulation of phased-array electronic steering limits as a relative-degree-two safety constraint with analytically verified Lie derivatives.
An ADMM solver with constant-time core factorization enabling real-time onboard execution.
Validation in both a nonlinear SE(3) simulation and a PX4 SITL environment, demonstrating elimination of all FoV violations and recovery of antenna gain through beam tightening.

Receiving RISs: Enabling Channel Estimation and Autonomous Configuration

Wed, 01 Apr 2026 00:00:00 +0000