Search Results (25,511)

Background: High-level badminton performance requires rapid perceptual processing, visuomotor coordination, and precise movement responses under continuously changing spatial conditions. Although wearable sports vision interventions have shown potential for enhancing perceptual–motor performance, evidence regarding their longitudinal effects and transfer to sport-specific outcomes remains limited. Trial design: A single-center, exploratory randomized controlled trial using a parallel-group structure. Simple randomization without blocking or stratification resulted in a final allocation ratio of 16:10 (approximately 1.6:1) between the training and control groups. Methods: Twenty-six collegiate badminton athletes aged 18–25 were randomized into a wearable sports vision training group (n = 16) or a control group (n = 10). The intervention group completed wearable sports vision training using Automatic Dual Rotational Risley Prisms (ADRRPs) for 15 min twice weekly over 4 weeks. Results: Baseline-adjusted ANCOVA demonstrated significant between-group effects for reaction time (p = 0.003) and target-zone accurate hits (p = 0.004), whereas binocular visual function outcomes did not show statistically significant between-group differences. No adverse events were reported. Conclusions: Four weeks of wearable sports vision training may be associated with improvements in selected visuomotor outcomes, particularly reaction performance and target-zone hitting accuracy, in collegiate badminton players. Larger trials are needed to evaluate long-term retention and broader sport-specific applicability. Trial registration: ClinicalTrials.gov Identifier: NCT07105462, registered 29 July 2025. Full article

The brake–release stability of electro-hydraulic thrusters (EHTs) significantly affects the safety of hydraulic braking systems, especially under low-temperature conditions with varying fluid viscosity. Most existing studies have focused on macroscopic braking characteristics, while the internal flow field variation and vortex evolution mechanism during the brake–release process remain insufficiently explored. In this work, transient CFD simulations are conducted to investigate vortex formation rules and flow field characteristics inside an EHT. Three typical vortex structures denoted as α, β, and γ are identified, and the independent and coupling influences of fluid dynamic viscosity and motor speed on vortex intensity and piston-bottom pressure are quantitatively analyzed. The results show that vortices α and β trigger flow disorder and additional hydraulic energy loss, while vortex γ optimizes flow uniformity and assists piston extension. Higher fluid viscosity exacerbates vortex development and pressure fluctuation, while increasing motor speed accelerates transient flow field evolution. This study clarifies the internal flow mechanism of EHT brake–release behavior and provides reliable parametric guidance for optimizing the low-temperature performance of electro-hydraulic braking systems. Full article

High-speed permanent magnet synchronous motors (PMSMs) used in electric pump-fed liquid rocket engines require stator shielding sleeves to prevent corrosive propellants from causing harm under cyclic pressure. However, metallic sleeves suffer significant losses due to eddy currents. Conversely, pure carbon fiber reinforced polymer (CFRP) sleeves have failed when exposed to 98% H₂O₂. Micro-CT analysis of a failed pump sleeve reveals a four-stage failure mechanism. Manufacturing defects caused matrix cracking, which propagated under pressure and thermal cycling. This progression resulted in the formation of through-thickness leakage paths, which ultimately triggered catalytic decomposition and explosion. To address these issues, an improved dual-layer sleeve is proposed, featuring a 2.5 mm PEEK 450G liner and a 2.0 mm T700S/epoxy CFRP overwrap. Finite Element Analysis (FEA) indicates peak von-Mises stresses of 86.25 MPa and 112.16 MPa, yielding Tsai–Wu safety factors of 2.9 and 1.7. Furthermore, various tests, including immersion, fatigue, burst, hydraulic, and thermal evaluations, demonstrate a burst margin of 2.37× at 7.12 MPa, with only 0.19% increase in mass. This design effectively eliminates leakage pathways while preserving zero eddy-current loss and ensuring a low weight. Full article

High-performance control of surface-mounted permanent magnet synchronous motors (SPMSMs) is critical for unmanned aerial vehicle (UAV) rotor servo systems, which demand fast dynamic response, high steady-state accuracy, and strong robustness against complex disturbances. However, conventional sliding mode control (SMC) methods often suffer from inherent issues like integral windup, persistent chattering, and sensitivity to parameter variations, limiting their effectiveness in such challenging applications. To address these limitations, this paper proposes a novel composite control strategy. The method integrates an improved terminal integral sliding mode controller (ITISMC) with an adaptive super-twisting reaching law (ADSTA) and a terminal integral sliding mode observer (TISMO). The key innovations include: (1) a redesigned sliding surface incorporating a smooth nonlinear function to suppress chattering and a variable-gain integral term to mitigate integral windup; (2) an adaptive reaching law that dynamically adjusts its gains based on the system state to balance convergence speed and chattering suppression; and (3) a disturbance observer that provides real-time estimation and feedforward compensation of total disturbances, significantly enhancing robustness. The proposed ITISMC-ADSTA-TISMO strategy was implemented and validated on a TMS320F28379D DSP-based experimental platform. Comparative results demonstrate its superiority over benchmark methods (e.g., SMC-STA). Key achievements include a rapid no-load startup time of 0.45 s, high steady-state precision with speed fluctuations suppressed to only 3 rpm, and superior disturbance rejection capability under sudden load changes, sinusoidal disturbances, and parameter perturbations. The method also yields favorable q-axis current response. These results confirm that the proposed strategy offers a high-performance, practical solution for advanced UAV servo control systems. Full article

Background/Objectives: This study evaluates the feasibility and preliminary effects of a short version of the Enriched Motor Program (EMP), an intervention combining aerobic and cognitive exercises, adapted to support the development of executive functioning in children with autism spectrum disorder (ASD). Executive functions are high-order cognitive abilities necessary to manage everyday social and adaptive tasks. Methods: The sample included two children with ASD (boys) with an average chronological age of eight years. The intervention was delivered once per week, over 12 weeks, and children’s executive functions were assessed before and after the intervention. Working memory was assessed using the Backward Word Span and the Mr. Cucumber tests; inhibitory control was measured via the Circle Drawing Task and the Day/Night Stroop. Results: The data for both children were analyzed using the Reliable Change Index (RCI), which indicated a reliable change in visuo-spatial working memory for the child with level 2 ASD. Conclusions: These findings provide encouraging preliminary results concerning the feasibility of a short version of the EMP. Enriched motor programs could be considered as suitable activities complementary to the main clinical therapy. Full article

This study proposes a human-centered multimodal framework for characterizing safety-relevant driver functional domains in professional bus drivers. Unlike conventional approaches that rely on isolated psychological or physical assessments, the proposed framework integrates self-perception, psychomotor performance, and cognitive–perceptual assessment to provide an exploratory, structured characterization of driver-related functional capacities. Eighteen professional bus drivers participated in this study. Self-perception data were obtained from all 18 participants, whereas psychomotor and cognitive–perceptual assessments were completed by 16 participants. These measurements were used to examine multiple domains relevant to driving safety, including behavioral awareness, motor coordination, attention, visual tracking, and hazard-perception-related processing. Given the modest sample size, the study should be regarded as an exploratory pilot investigation. Data were analyzed using a laboratory-based cross-sectional between-subjects design to examine age- and gender-related differences across the assessed domains. The findings suggested that selected age- and gender-related differences and descriptive tendencies were observable across multiple domains. Male drivers descriptively showed higher self-rating scores, female drivers showed different performance tendencies in selected psychomotor tasks, and male drivers demonstrated substantially greater grip strength. Older drivers showed slower and less efficient performance in several cognitive–perceptual measures, with the clearest age-related effect observed in the tachistoscopic traffic test, where older participants showed a higher error tendency under time-constrained traffic-scene processing conditions. The constructs and measures proposed in this study are intended as general laboratory-based assessments of driver-related capabilities rather than direct measures of actual driving performance, real-time driver-state indicators, or validated sensor-based monitoring indicators. As candidate human-factor constructs, they may inform future driver monitoring research by helping clarify how driver-related signals or behaviors could eventually be linked to underlying functional and safety-related meaning in intelligent transportation environments. Full article

This paper presents a robust fault-tolerant control (FTC) strategy for a multiphase PMSM-based propulsion system. The proposed approach combines an innovative super-twisting sliding mode controller (IST SMC) with a fault-tolerant model of the machine when an open-circuit fault occurs. The electrical propulsion system mainly has a two-line structure with a single DC source, a five-leg inverter and a Five-Phase Permanent Magnet Synchronous Motors (5-Φ PMSM), suitable for marine propulsion applications. Two main scenarios are investigated in this work. Firstly, if an open-phase fault occurs in one of the two 5-Φ PMSMs, a reconfiguration step of the machine control is applied in order to improve the performance of the propulsion system and to ensure the continuity of operation. Then, if the fault occurs in one of the two inverters, the faulty one is removed and the electrical series connection is made between the two machines, where they are powered by a single five-arm inverter, thus ensuring the continuity of operation of the system. Considering these two scenarios, a comparative analysis is made between the IST SMC and the classical PI controllers in terms of robustness to uncertainties, external disturbances and tracking accuracy for healthy and faulty operation modes, and during transient states. Full article

(1) Background and Objectives: Parkinson’s disease’s (PD) underlying pathophysiology still remains incompletely understood, with Braak’s hypothesis of ASyn pathology propagation being the most widely accepted. Recently, a novel model has been introduced, proposing two distinct ASyn propagation pathways: a bottom-up trajectory termed Body-first PD, and a central nervous system (CNS)-initiated pathway termed Brain-first PD. This distinction introduces new perspectives in the PD literature landscape regarding diagnosis, prognostic factors and patient management. This study set out to systematically synthesize the current literature comparing Brain-first and Body-first PD, with a focus on clinical characteristics and disease progression, diagnostic biomarkers, and management approaches. (2) Materials and Methods: A systematic literature search was conducted in March 2025 using PubMed, Cochrane Library, DOAJ and Google Scholar. Human observational, diagnostic, and interventional studies published between 2019 and March 2025, including patients with de novo or early PD, were eligible. Pre-motor REM sleep behavioral disorder (RBD) was used as the primary differentiation criterion. Risk of bias was evaluated using the Joanna Briggs Institute (JBI) critical appraisal checklists. Results were synthesized using a narrative approach. (3) Results: Sixteen studies comprising 2107 PD patients met the inclusion criteria. Body-first PD was associated with a higher non-motor symptom (NMS) burden, faster disease progression, and a higher prevalence of cognitive impairment. Additionally, Body-first PD patients exhibited more widespread and symmetrical neurodegeneration, along with electrophysiological and metabolic differences. Distinct biomarker and microbiome profiles were also observed between subtypes. No eligible studies addressing management approaches were identified. (4) Conclusions: In conclusion, the available evidence suggests that Brain-first and Body-first PD may represent two distinct pathophysiological entities, a proposal with great significance for the diagnosis, prognosis and management of PD patients. However, the predominantly cross-sectional nature of the current literature limits causal inference. Future longitudinal and interventional studies are required to clarify the potential clinical implications of this subtype classification theory. Full article

This work presents a pilot study to analyze the effect of aging on motor performance of young adults (YAs) and older adults (OAs) through wrist movement assessment, using an upper limb rehabilitation robot (ULRR) in passive mode coupled to a maze-solving task serious video game. The proposed approach considers the use of kinematic metrics, such as ROM, path accuracy, and movement smoothness, as quantitative biomarkers that evidence differences between YAs and OAs. An experimental protocol was conducted with 20 participants: 10 OAs and 10 YAs. Standardized wrist movements corresponding to flexion (F), extension (E), radial deviation (R), and ulnar deviation (U) were assessed at each level of the maze. The kinematic analysis was based on metrics for range of motion (ROM), path accuracy, smoothness, and root-mean-square error (RMSE) in trajectory tracking. The results revealed clear differences between the groups: the YAs achieved a greater ROM and made fewer errors on mean (2.167 errors for YAs compared to 6.000 errors for OAs), and showed a lower RMSE, while the OAs showed greater smoothness in their movements, because the YAs exhibit greater variability and disturbances in movement when correcting and controlling their movements to achieve good performance, reflecting more precise motor control and a greater capacity for error correction during movements with trajectory constraints. Full article

Electric power steering (EPS) motors require low torque ripple, low cogging torque, and smooth torque output to ensure precise control and driving comfort. However, consequent pole permanent magnet synchronous motors (CP-PMSMs), although advantageous in reducing permanent magnet usage, exhibit an imbalanced magnetic flux distribution due to the iron poles, resulting in even-order harmonic components in the back electromotive force (BEMF) and significant torque ripple. In this paper, a rotor pole arrangement for CP-PMSMs is proposed to improve torque characteristics for EPS applications. Symmetric and asymmetric pole arrangements are introduced to modify the magnetic flux distribution and suppress harmonic components generated by the iron poles. In addition, the iron pole arc ratio is selected as a key design variable and analyzed for each model to achieve low torque ripple while maintaining torque performance. The electromagnetic characteristics of the proposed structures are evaluated using finite element analysis under identical operating conditions. The results show that the torque ripple of the proposed models is reduced by approximately 33.3%p and 34.1%p compared with the conventional CP-PMSM, and the cogging torque is also significantly reduced. Although average torque decreases, overall torque characteristics improve due to reduced torque ripple and harmonic components. These results demonstrate that the proposed rotor pole arrangement effectively enhances torque quality in CP-PMSMs without increasing axial length or requiring three-dimensional analysis. Full article

The higher the rotational speed of the telescope dome, the greater the vibration and noise are induced, which results in a more significant impact on telescope imaging performance, while also requiring greater driving power and increasing the control complexity. Therefore, this paper primarily focuses on appropriately reducing the dome speed during high-speed space target tracking without affecting observation effectiveness. First, the initial tolerance of the dome opening in the telescope’s horizontal state is introduced, and the variation pattern of the initial tolerance with the telescope’s elevation angle is derived; then, the angular velocity relationship between the dome and the telescope is established, and the rotational trajectory of the dome is replanned. Taking the International Space Station as an example for simulation, the results show that the maximum velocity of the dome is reduced by 25.4% compared with that of the telescope, with no field-of-view obscuration during the entire observation process. Finally, a multi-motor servo control system for the dome is designed, and practical tests demonstrate that during synchronous tracking with the telescope, the synchronization error PV of all motors is less than 2.5%, the dome tracking accuracy is better than 60″, and the maximum dome speed is reduced by approximately 33.3% compared with the telescope. This research is of great significance for appropriately reducing the dome speed requirement, alleviating high-speed vibration and noise, and simplifying control difficulty in high-speed tracking. Full article

Background: Portable biofeedback technologies are increasingly used in rehabilitation; however, the validity of surface electromyography (sEMG) as a surrogate indicator of deep abdominal muscle function remains unclear. This study aimed to validate a portable sEMG-based visual biofeedback system by examining its relationship with ultrasound-derived measures of deep abdominal muscle activation. Methods: Twenty-nine healthy adults were randomly assigned to a Visual Biofeedback group (n = 14) or a Verbal Feedback group (n = 15). Both groups performed a standardized 2-week core stabilization program. Muscle activation of the deep abdominal muscle complex (transversus abdominis–internal oblique; TrA–IO) and external oblique (EO) was measured using sEMG (%MVIC), while ultrasound imaging was used to assess transversus abdominis thickness and contractile activity (ADIM–Rest index). Between-group differences and correlations between EMG and ultrasound variables were analyzed. Results: The Visual Biofeedback group demonstrated significantly greater improvements in TrA–IO activation and in the preferential activation ratio (TrA–IO/EO) compared to the Verbal group (p = 0.004). Ultrasound analysis revealed significantly greater increases in TrA thickness and contractile activity in the Visual group (p < 0.001). A significant positive correlation was observed between changes in TrA–IO activation and TrA thickness (ρ = 0.51, p < 0.001). Conclusions: Portable sEMG-based visual biofeedback demonstrated physiological relevance by reflecting ultrasound-derived changes in deep abdominal muscle function. These findings support the use of sEMG as a practical surrogate tool for monitoring deep core muscle activation and highlight the potential of portable biofeedback systems in scalable and accessible rehabilitation. Full article

Accurate modeling of dependence in insurance data is essential for pricing, reserving, and capital allocation, particularly when claim frequencies and severities interact in complex ways. Classical independence assumptions often fail in practice, and standard copula models face challenges when applied to discrete or mixed data. This paper develops a nonparametric framework for dependence modeling in count–count and hybrid frequency–severity settings using Sklar-type density estimation. Two exact Sklar-type decompositions clarify the structure of dependence in discrete data, while a kernel-based analogue and a hybrid estimator provide flexible, fully nonparametric tools for discrete and mixed insurance variables. A comprehensive simulation study across multiple sample sizes and dependence levels evaluates estimator performance using several divergence measures. An application to a motor-insurance dataset demonstrates that the proposed methods capture dependence patterns with high fidelity and yield accurate joint distribution estimates. The results highlight the practical value of nonparametric Sklar-type estimators for contemporary actuarial modeling involving discrete or hybrid data. Full article

Robotic assistive devices, such as exoskeletons, are increasingly employed in walking rehabilitation. Therefore, the measurement of both movement kinematics and cognitive workload is important to understand this human–robot interaction in real-world contexts. To address this need this study presents the validation of a framework integrating inertial motion capture (Xsens) and eye-tracking sensor (Pupil Neon) within a Mixed Reality (Meta Quest 3) architecture. We developed an overground dual-task paradigm in which holographic numbers appear in the user’s peripheral vision. This setup actively stimulates visuospatial attention while quantifying kinematic and cognitive output. To validate the framework, the protocol has been tested on 30 healthy subjects across repeated exoskeleton training sessions. Statistical analyses revealed that the Coefficient of Multiple Correlation (CMC) and Spectral Arc Length (SPARC), calculated on the shank angular velocity, together with the Step Length Variability, exhibited significant time effects (p < 0.01), mapping the transition toward automated gait. Concurrently, pupillometric data demonstrated a measurable reduction in neurocognitive demand; specifically, the Task-Evoked Pupillary Response (TEPR) decreased significantly across progressive training sessions (p < 0.05). With this work, we validated a measurement protocol that aims to provide a novel methodology for objectively evaluating motor and cognitive adaptation in wearable assistive devices. Full article

This article proposes a double-pre-warped Tustin bi-quad filter (DPT-BQF) to suppress mechanical resonance for non-contact integrated permanent magnet vernier motors (NIPMVMs). First, this article analyzes how conventional notch filters suffer from distortion in notch frequency, bandwidth, and depth when discretized with low-precision methods, which degrades filtering performance and weakens resonance suppression. To address this issue, the inherent limitations of the pre-warped Tustin discretization for BQFs are discussed. On this basis, a double pre-warped Tustin method is proposed by compensating for the bandwidth distortion, and its discretization performance is comprehensively evaluated. Furthermore, the principle, parameter design, and robustness range of the filter are deeply analyzed in the discrete domain. Finally, experimental validation on an NIPMVM test platform demonstrates the effectiveness and feasibility of the proposed method. Full article