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Hengfei Zhao

Publications and source records attributed to Hengfei Zhao.

6 recordsLinked to original sources

Towards Trustworthy Embodied Intelligence: A Systems Framework and Graded Trustworthiness Levels

Embodied intelligence integrates learned perception and decision making with real-time computation, control, and physical interaction. Because failures can cause immediate physical or operational harm, task completion alone does not establish trustworthiness. We define trustworthy embodied intelligence as the sustained capacity to execute specified tasks reliably under environmental and system variation while maintaining risk within acceptable bounds. We term this objective sustained safe success. Its supporting mechanisms are organized into four interdependent layers. The model layer generates task-competent action proposals with calibrated uncertainty and explicit safety preferences. The system layer realizes authorized actions dependably through integrated sensing, computation, control, hardware safeguards, fault containment, and fallback. The evidence layer substantiates bounded claims through evaluation, verification, validation, traceability, and structured assurance arguments. The deployment layer maintains claim validity through runtime monitoring, authority management, intervention, incident response, and controlled updates. Because assumptions and failures propagate across these layers, neither model capability, isolated safeguards, nor benchmark performance alone can establish end-to-end trustworthiness. Drawing on embodied AI, robotics, control, dependable computing, distributed systems, and autonomous driving, we further propose a non-normative hierarchy of trustworthiness levels. This hierarchy grades the strength of bounded deployment claims across task capability, safety, system assurance, operational governance, and supporting evidence, providing a basis for bounded deployment, comparative evaluation, research prioritization, and future standardization.

cs.RO

TaCauchy: An Extensible FEM Framework for Vision-Based Tactile Simulation

Vision-based tactile sensors require high-fidelity simulation for reinforcement learning, yet existing approaches struggle to provide accurate mechanical stress fields within GPU-accelerated robotics platforms. We present TaCauchy, an extensible Finite Element Method (FEM) framework that integrates rigorous physics-based force computation into Isaac Sim. Built on the Unified Incremental Potential Contact (UIPC) solver, TaCauchy directly computes Cauchy stress tensors from hyperelastic constitutive laws and projects them onto contact surfaces to obtain traction forces and pressure distributions, providing mechanical ground truth from first principles rather than empirical estimation. Our framework features automatic mesh generation with geometry-aware adaptive refinement and a modular sensor interface enabling rapid integration of diverse sensors (GelSight Mini, DIGIT, 9DTact) with minimal configuration. Performance benchmarks demonstrate 33.40 FPS for single environments and 555 FPS aggregate throughput across 60 parallel environments, with stress extraction overhead under 1 ms. Physical validation experiments show strong agreement between simulated and real tactile responses across force ranges from 1.2556 N to 4.7332 N, achieving SSIM above 0.93, confirming the framework's capability to provide accurate, physically-grounded force supervision for downstream robotic manipulation tasks.

cs.RO

Heavy mesons with dynamical gluon on the light front

We investigate the structure of charmonium, bottomonium, and $\rm B_c$ meson systems within the Basis Light-Front Quantization (BLFQ) approach, including both the quark-antiquark ($|q\bar{q}\rangle$) and quark-antiquark-gluon ($|q\bar{q}g\rangle$) Fock sectors. Our input light-front Hamiltonian incorporates a confining potential inspired by light-front holography, as well as the quark-gluon interaction from Quantum Chromodynamics. By adjusting model parameters to reproduce the mass spectra for low-lying states, we obtain the light-front wave functions for the heavy meson states. Based on these wave functions, we calculate electromagnetic form factors, decay constants, parton distribution amplitudes (PDAs), and parton distribution functions (PDFs) of the quarks and gluons in the heavy mesons. Our results for the charge radii and decay constants reasonably agree with experimental data and other theoretical approaches. The PDAs are consistent with the predictions from the earlier BLFQ calculations with an effective one-gluon exchange interaction. Furthermore, we present the first predictions within the BLFQ framework for the gluon PDFs in heavy mesons based on the light-front wave function in the $|q\bar{q}g\rangle$ sector.

hep-ph

Positronium: an illustration of nonperturbative renormalization in a basis light-front approach

We calculate the mass spectrum and the structure of the positronium system at a strong coupling in a basis light-front approach. We start from the light-front QED Hamiltonian and retain one dynamical photon in our basis. We perform the fermion mass renormalization associated with the nonperturbative fermion self-energy correction. We present the resulting mass spectrum and wave functions for the selected low-lying states. Next, we apply this approach to QCD and calculate the heavy meson system with one dynamical gluon retained. We illustrate the obtained mass spectrum and wave functions for the selected low-lying states.

hep-ph

Recent Progress in Basis Light-front Quantization

Basis Light-front Quantization (BLFQ) is a nonperturbative approach to quantum field theory. In this paper, we report our recent progress in applying BLFQ to the positronium system in QED and to the meson and the baryon system in QCD. We present preliminary results on the mass spectrum, light-front wave functions and other observables of these systems, where one dynamical gauge boson is retained for the positronium and meson systems.

nucl-th

Positronium on the light front

Basis Light-front Quantization (BLFQ) is a newly developed nonperturbative approach, aiming at solving relativistic bound systems based on the Hamiltonian formalism of light-front dynamics. In this work, we introduce its application to the positronium system at strong coupling, $α= 0.3$, with a dynamical photon mediating the interaction between the positron and the electron. Nonperturbative mass renormalization is needed to cancel the fermion self-energy divergence. Here, we present the resulting mass spectrum, light-front wave functions (LFWFs), and the photon distribution inside positronium.

nucl-th