arXiv subjects

Xiao Jie

Publications and source records attributed to Xiao Jie.

3 recordsLinked to original sources

arXiv2026

Aerodynamic Prior-Free Coordinated Trajectory Generation and Tracking Control for a Tail-Sitter UAV

This paper presents a coordinated trajectory generation and tracking control framework for a tail-sitter unmanned aerial vehicle (UAV), which does not require aerodynamic priors identified for a specific airframe while addressing the challenge of flight control under highly nonlinear aerodynamics across the full flight envelope. The core innovation lies in employing phase-specific aerodynamic modeling strategies for planning and tracking, tailored to their distinct functional characteristics, without requiring airframe-specific aerodynamic priors. Specifically, the phi-theory model under coordinated flight is employed to derive an analytic differential flatness mapping, and a simplified but locally accurate model is established for predictive control to enable real-time aerodynamic parameter estimation. The proposed framework is evaluated extensively through both simulation and challenging real-world flight tests under mild wind conditions, showing high-precision tracking and adaptability across the tested aerodynamic conditions. To the best of our knowledge, this is the first real-world demonstration of accurate trajectory tracking over tested flight regimes spanning the full envelope of a tail-sitter UAV without relying on aerodynamic identification campaigns. The source code of our framework is available at: https://github.com/SYSU-HILAB/AP-PnC.

cs.RO↗

arXiv2026

A Sharp Capacity Gauge Solution to the Open Problem of Quasisymmetric Composition on $\mathcal{Q}_α(\mathbb R^n)$

The spaces $\mathcal Q_α(\mathbb R^n)$ for the critical index range $α\in(0,\min\{1,n/2\})$ form a scale-invariant family lying strictly between the space of constant functions and $\mathrm{BMO}(\mathbb R^n)$. A long-standing open problem, posed by Essén, Janson, Peng and Xiao in 2000, asks to characterize the quasisymmetric mappings $φ:\ \mathbb R^n\to\mathbb R^n$ for which the composition operator $\mathcal C_φ(f)=f\circφ^{-1}$ is bounded on $\mathcal Q_α(\mathbb R^n)$. This paper establishes the full intrinsic characterization by introducing a new geometric quantity, the capacity gauge $\|φ\|_{\mathscr G_β}$, which measures the distortion of $φ$ through pullback volume ratios along the dyadic tree. We prove that for any quasisymmetric mapping $φ$ (with a mild Muckenhoupt $A_\infty(\mathbb R)$ assumption on the Jacobian determinants of $φ$ and $φ^{-1}$ when $n=1$), the composition operator $\mathcal C_φ$ is bounded on $\mathcal Q_α(\mathbb R^n)$ if and only if $\|φ\|_{\mathscr G_{1-\frac{2α}{n}}}<\infty,$ with quantitative equivalence $$ \|\mathcal C_φ\|_{\mathcal Q_α(\mathbb R^n)\to\mathcal Q_α(\mathbb R^n)}^2 \simeq \|φ\|_{\mathscr G_{1-\frac{2α}{n}}}. $$ This sharp, necessary and sufficient characterization refines earlier sufficient criteria of Koskela, Xiao, Zhang and Zhou in 2017, which were formulated in terms of local or global self-similar Minkowski dimension of the exceptional sets of the Jacobian. As applications, we obtain the composition stability of the finite capacity gauge, the invariance of $\mathcal Q_α$-removability under quasisymmetric mappings with finite capacity gauge, and the propagation of $\mathcal Q_α(\mathbb R^n)$-regularity and initial-data stability for transport equations driven by quasisymmetric flows.

math.CA↗

arXiv2018

Realizing Thermoelectric and Thermistor Bi-functionalities via Triggering Electron Correlations with Lattice-dipole

Establishing strong electron-correlations not only shed lights on overcoming the trade-off limitations for optimizing thermoelectric materials, but can also introduce new functionalities that extend the vision of conventional thermoelectric applications. Here, we demonstrate that the high thermoelectric and thermistor functionalities coexist in lattice distorted SrNbxTi1-xO3 films with electron correlations between carriers and ordering aligned lattice dipoles. As-grown SrNbxTi1-xO3/SrTiO3 with effectively preserved interfacial strains exhibits cross-plane charge ordering and orbital anisotropy, as indicated by the polarization dependent near edge X-ray absorption fine structures. The resultant coulomb-correlations regulate the carrier transport and enhance the Seebeck coefficient more independently via enlarging the system vibration entropy. As-achieved maximum thermoelectric power factor exceeds 100 uWcm-1K-2 measured in the bulk performance of SrNb0.2Ti0.8O3 (2.2 um)/SrTiO3 (100 um), which is comparable to the best thermoelectric materials for low temperature applications. In addition, the strong temperature dependence of the carrier scattering aroused by the lattice dipoles introduces a positive temperature dependent thermistor transportation behavior with large temperature coefficient of resistance ranging from 30 to 300 K, which is rarely seen in conventional thermistors. Combining both functionalities largely extend the horizon in exploring new Joule sensors for detection of temperature and thermal perturbations across a broad temperature range.

cond-mat.mtrl-sci↗