Search Results (1,255)

Commercial lead zirconate titanate (PZT) ceramics are widely employed in electromechanical devices due to their excellent piezoelectric response and operational stability. This study investigates the influence of polarization temperature and time on the electromechanical performance of commercial Sparkler PZT-4 (Navy Type I) ceramics. Samples were compacted, sintered at 1230 °C, and polarized under temperatures ranging from 80 to 110 °C for 2, 8, and 15 min using a constant electric field of 3.0 kV/mm. Microstructural, physical, and crystallographic analyses confirmed the successful processing of the ceramics, yielding an apparent density of 7.68 g/cm³, relative density of 96.02%, and the predominance of the tetragonal Pb(Zr,Ti)O₃ perovskite phase. Electromechanical characterization revealed a strong dependence of the piezoelectric coefficient (d₃₃) and electromechanical coupling factor (K_p) on the polarization conditions. Maximum values of d₃₃ = 325.8 pC/N and K_p = 0.509 were obtained under elevated temperatures and longer polarization times. A phenomenological Avrami approach indicated faster apparent domain alignment at higher temperatures, while ANOVA and Tukey tests confirmed the significant influence of polarization parameters on the electromechanical response. The results identify favorable polarization conditions for commercial PZT-4 ceramics used in sensors, actuators, and ultrasonic transducers. Full article

The motion of AC electromagnetic actuators exhibits complex electrical–magneto–mechanical coupling characteristics. A three-phase AC contactor is taken as the typical research object in this paper. Using the finite-element method (FEM) and mesh deformation technique, the commercial software COMSOL Multiphysics is adopted to analyze its static electromagnetic characteristics, together with the operational coil current response and movable core displacement. In addition, the static correlation between the magnetic force, air gap, and time-varying magnetic force curves in the movement process are obtained. An experimental platform is established to measure the magnetic force of electromagnetic actuators. The experiment results demonstrate the feasibility of the proposed simulation method. The normalized root mean square errors between simulated and measured static magnetic forces are below 8% under all tested coil voltages. Furthermore, the effect of coil voltage phase angle on dynamic operational characteristics is thoroughly investigated. Combined with the closing time and final velocity of the movable core, the recommended operating window and its corresponding phase angle are determined. Full article

Effective thermal management is crucial for the performance, thermal safety, and lifespan of lithium-ion batteries in electric vehicles (EVs). Thermal management strategies are essential for preventing overheating, thermal imbalance, and the associated risk of thermal runaway. Nanofluids are emerging and attracting considerable attention as potential coolants for high-power energy storage and electronics systems. This review updates and summarizes the most recent advances in nanofluid-based cooling strategies for battery thermal management systems (BTMSs) over the past five years, emphasizing their implications for battery thermal safety. Three main nanofluid-based cooling strategies have been evaluated in depth, including nanofluid-based indirect liquid cooling, nanoparticle-enhanced PCM cooling, and nanofluid-based heat pipe cooling. Various nanofluid formulations, including mono, hybrid, and ternary nanofluids, have been considered and evaluated for their heat dissipation under high charge/discharge and abuse-relevant conditions. Thermal and hydraulic performance characteristics, including maximum temperature, maximum temperature difference, and pressure drop, have been comprehensively evaluated for different nanofluid-based cooling strategies. The findings demonstrated that nanofluids significantly improved heat transfer rates and enhanced temperature control efficiency. In particular, hybrid and ternary nanofluids exhibit superior thermal performance and effectively suppress the escalation of safety-critical temperatures. Beyond summarizing cooling performance, this review further discusses the role of nanofluid-based cooling strategies as functional thermal-control layers within intelligent BTMS architectures. Particular attention is given to their compatibility with sensing networks, BMS-/VCU-level supervisory control, predictive thermal models, actuator responsiveness, fault-warning algorithms, and long-term reliability under realistic driving and fast charging conditions. Therefore, this review provides architecture-oriented insights for developing safe, energy-efficient, and control-ready BTMSs for next-generation high-power and connected EVs. Full article

With the rapid proliferation of industrial robots, compact electric motors have become increasingly critical for robot joint actuation. This paper proposes a fan–trapezoidal combined magnetic pole and auxiliary pole structure. A three-dimensional simulation model of a disk-type motor incorporating this magnetic pole configuration is established using the finite element analysis method. Its electromagnetic characteristics are then investigated through finite-element simulations and optimization analysis. With the total harmonic distortion (THD) of the air-gap flux density as the primary optimization objective, the optimal design is selected by adjusting the fan–trapezoidal pole angle and the dimensions of the soft magnetic auxiliary poles. The accuracy of parametric optimization is subsequently verified by employing the multi-objective genetic algorithm (MOGA). The results indicate that for a coreless axial-flux permanent magnet motor equipped with the proposed fan–trapezoidal combined poles and auxiliary poles, the THD of the air-gap flux density is reduced to 3.53%. This represents a reduction of 38.72% compared to an optimized conventional modular-pole structure. Furthermore, the harmonic distortion rate of the no-load back electromotive force decreased by 83.91%. The sinusoidal characteristics of the air-gap flux density waveform are significantly improved. This work provides insights into the design of coreless axial-flux permanent magnet motors. Full article

In order to control an electro-hydrostatic actuator (EHS), as is well known in the literature, it is possible either to modify the speed and direction of rotation of the electric motor or to vary the displacement of the hydraulic pump. In a previous paper, the advantages and disadvantages of each solution were highlighted. Varying only the motor speed leads to demanding operating conditions for the electric motor, whereas varying only the hydraulic pump displacement results in continuous energy consumption that becomes excessive during long-duration flights. Combined solutions for controlling an EHS can also be found in the literature, but they generally require highly sophisticated control algorithms. In this paper, a solution is proposed in which the electric motor is switched off when the EHS remains in an idle condition for long periods of time. In this way, the large amount of energy consumed during idle operation is eliminated, while preserving the improved dynamic performance associated with the variable-displacement pump configuration. Full article

Magnetically actuated catheters have attracted increasing attention for minimally invasive interventions because they enable remote, non-contact steering in confined and tortuous anatomical environments. However, integrating magnetic actuation, electroablation capability, and high structural compliance into a single soft catheter remains challenging. Here, we present a coaxially printed magnetically actuated electroablation catheter (MEC). The MEC is fabricated via a coaxial 3D printing process, combining a highly flexible PDMS outer sheath with a continuously deformable eutectic gallium–indium (eGaIn) conductive core, followed by the distal assembly of a magnetic ring and a copper electrode. This structural design preserves intrinsic mechanical flexibility while maintaining stable electrical conductivity under bending deformation. To achieve active catheter steering, an eight-axis electromagnetic actuation system was developed to generate controllable magnetic fields for tip deflection and guidance. The MEC exhibited effective navigation and manipulation in maze traversal and selective navigation within a 3D-printed vascular model. Furthermore, ex vivo porcine liver and in vivo rat liver electroablation experiments verified that the MEC could be magnetically navigated to designated sites for localized electroablation. This work provides a new strategy for precise, minimally invasive ablation of target tissues in confined and difficult-to-access anatomical environments. Full article

To investigate the dynamic characteristics of key parameters in a piston gravity energy-storage system, an experimental system for novel piston gravity energy storage is designed and developed. Firstly, the structure and working principle of the piston gravity energy-storage system are analyzed. Adopting a modular modeling approach, the system is divided into four core modules, and the piston motion, vertical cylinder chamber pressure, hydraulic actuator, and turbine power models are established. Subsequently, a case study simulation is conducted on the piston gravity energy-storage system to model its dynamic characteristics during discharge conditions, analyzing the variation patterns of key parameters such as the chamber pressure, flow rate, and output power within the system. Finally, the experimental system integrates a digital controller with proportional–integral power regulation and an automatic mode switching logic to enable the constant power closed-loop control, with real-time acquisition of the chamber height, pressure, flow rate, and electrical parameters. The dynamic responses of various system parameters are analyzed. Experimental results indicate that under constant power charging and discharging conditions, the height of the upper chamber exhibits a linear trend, the pressure in the lower chamber is inversely proportional to the height of the upper chamber, and the flow rate remains stable with charging and discharging power. Neglecting energy losses of the pump and hydraulic turbine and only considering friction and hydraulic losses, the charge–discharge efficiency of the energy-storage experimental system is 65%. Full article

Elevators exemplify mechatronics by integrating mechanical, electrical, and software systems. This paper discusses a four-story tabletop elevator model developed to demonstrate mechatronics and automation concepts in engineering education. The system utilized an Arduino MEGA microcontroller, 3D-printed components, an integrated servo motor, and standard electronics to replicate commercial elevator logic. The physical design features a ball screw linear actuator for vertical motion. It replicates dual-door systems with one door on the moving car and fixed doors at each floor that open simultaneously upon arrival. Development included designing the physical model, prototyping control algorithms, and integrating hardware and software. The model successfully demonstrated key functions: automatic dual-door operation, safety interlocks, smooth inter-floor motion, responsive floor-selection buttons with LED feedback, and efficient routing algorithms prioritizing requests based on current direction and location. Performance testing confirmed that the model accurately replicates modern elevator behavior and serves as an effective educational tool. Full article

Solar tracking systems (STSs) are widely adopted in photovoltaic (PV) installations to increase energy yield by maintaining favorable module orientation relative to the sun’s trajectory. This paper presents a systematic review of STSs from an electrical engineering perspective, focusing on electrical performance, control strategies, and system integration aspects relevant to grid-connected PV applications. Fixed-tilt, single-axis, and dual-axis configurations are comparatively assessed in terms of output power, annual energy yield, influence on I–V and P–V characteristics, and auxiliary power consumption. The analysis emphasizes net energy gain rather than gross energy improvement. Control strategies are classified as open-loop, closed-loop, hybrid, and intelligent approaches. Their impact on tracking accuracy, actuator duty cycles, electrical stability, and coordination with maximum power point tracking (MPPT) algorithms is critically examined. A bibliographic and scientometric analysis is conducted to identify research trends, dominant themes, and existing gaps. The results indicate that single-axis tracking often provides the most favorable balance between energy gain and auxiliary consumption in utility-scale systems, while dual-axis configurations achieve higher absolute yield at increased complexity. The review highlights the need for standardized net-energy evaluation and grid-aware tracking strategies. Full article

The shift toward more electric aircraft has intensified thermal management challenges due to increased heat load from electrical actuators, power electronics and energy storage systems concentrated within confined fuselage bays. A Conventional Environmental Control System (ECS) alone is not sufficient to dissipate such high localized heat loads. This creates the need for innovative heat dissipation and heat reuse strategies. This paper presents two thermal management concepts evaluated at the Fraunhofer Flight Test Facility. The first, developed in the ORCHESTRA project, integrates a bilge skin heat exchanger with modified ventilation to dissipate elevated heat loads. The second, under investigation in the TheMa4HERA project, focuses on reusing avionics heat to warm the FWD cargo hold, thereby reducing ECS power demand. Both concepts depend on convective heat exchange, characterized using Fraunhofer’s Convective Heat Transfer Meter (CHM) to determine key heat transfer coefficients. In parallel, an aircraft-level thermal model was developed, validated against experimental data and subsequently used for virtual demonstration of a ground test scenario. Full article

The widespread adoption of photovoltaic systems in residential electrical installations has increased the importance of Automatic Transfer Switches (ATSs) for ensuring power continuity during grid outages. However, many low-cost ATS solutions available on the market prioritize economic efficiency over operational safety, leading to significant risks under fault conditions. This paper investigates a real overvoltage incident in a residential three-phase installation equipped with a photovoltaic inverter and an ATS, which resulted in the failure of multiple electronic loads. The study reconstructs the event and demonstrates that the loss of the neutral conductor during backup operation caused severe phase voltage imbalance, generating overvoltage conditions across lightly loaded phases. A simplified electrical model is used to explain current paths and voltage redistribution under asymmetric loads, highlighting the critical role of correct neutral switching in ATS design. Two commercially available ATS architectures, one based on a changeover-contact mechanism and one employing four-pole miniature circuit breakers, are experimentally evaluated. The evaluation reveals major design deficiencies, including the absence of protective elements for control circuits, reliance on mechanical end-position limiters, and the use of switching devices not intended for frequent source transfer. These shortcomings introduce risks such as uncontrolled actuator operation, overheating, mechanical damage, and potential fire hazards. To overcome these limitations, a new ATS architecture was developed using a phase-monitoring relay, interlocked ABB contactors, and dedicated fuse protection for all control circuits. Detailed laboratory measurements were conducted to characterize contactor switching times and internal relay command delays. By optimizing the command sequence, the proposed ATS achieves predictable, fault-tolerant operation with competitive transfer times, representing a meaningful safety improvement over the evaluated commercial alternatives. The proposed solution is scoped to three-phase residential installations equipped with a hybrid photovoltaic inverter providing a dedicated backup output, operating within TN-S or TN-C-S earthing systems with a maximum grid connection capacity of 21 kW. Full article

In the context of reducing air transport emissions, operational costs and transitioning to more electric aircraft, there is a growing need to develop new ice protection systems. Resonant electromechanical de-icing (EM-DI) systems take advantage of the resonance to amplify vibration amplitudes applied through piezoelectric actuators, generating stress in the ice layer, enabling its removal. Research conducted on such systems has been focused on simplified or reduced models, and assessment of aircraft-level requirements has seldom been conducted. To overcome this shortcoming, this work proposes a pre-sizing methodology to evaluate the requirements (power consumption and piezoelectric mass) of EM-DI systems. After dividing the protected area into modules to cycle the aircraft de-icing, finite element models including the ice and the modules’ structure are developed. A modal analysis is performed to identify the extensional resonance modes that enable de-icing, and to calculate the necessary power and piezoelectric mass based on shedding criteria. The methodology is illustrated for two typical aircraft configurations: a jet engine single-aisle aircraft (SA) and a regional turboprop aircraft (TP). The results obtained for the EM-DI technology are promising, with apparent power estimates of as little as $2.7\mathrm{kVA}/{\mathrm{m}}^2$ for the SA and $1.28\mathrm{kVA}/{\mathrm{m}}^2$ for the TP. Full article

Wafer-level testing of Photonic Integrated Circuits (PICs) represents a critical throughput bottleneck in silicon photonics manufacturing, particularly as co-packaged optics demand testing of thousands of optical I/O per wafer. This work introduces optimized alignment algorithms for the Technoprobe Eclipse Dynamic probe card system, which integrates electrical probes and a piezoelectrically actuated fiber array unit within a single probe head, eliminating external positioning equipment. We systematically evaluate seven alignment algorithms: Reference Coarse Scan, Reference Coarse+Fine Scan, Cross Scan, Local and Global Bayesian Optimization, Variable and Fixed Gradient Ascent. The evaluation is made across 72 simulated test cases derived from eight experimental datasets through systematic spatial windowing, combined with experimental validation. Performance is assessed under four operating regimes—high-speed (HS) and low-speed (LS) operation, each with or without hysteresis compensation (H/NH). Experimental validation across eight die positions confirms 100% success rate for both Local Bayesian (98.24% accuracy in 99.87 arbitrary units (a.u.)) and Fixed Gradient (99.18% accuracy in 154.01 a.u.) baseline algorithms. Comprehensive simulation results with improved algorithms across all four scenarios reveal distinct performance characteristics. Fixed Gradient achieves the highest reliability (95.8%) with 99.4% average accuracy across all operating conditions. Variable Gradient provides the fastest alignment (1.18 a.u. in HS-NH) with 90.3% reliability. Local Bayesian demonstrates 94.4% reliability with intermediate performance. Global Bayesian Optimization achieves the best sample efficiency (average 24 steps) but exhibits scenario-dependent reliability ranging from 88.9% (HS-H, LS-H) to 93.1% (LS-NH). For the ideal production scenario, high speed with effective hysteresis compensation (HS-NH), Fixed Gradient emerges as the optimal choice, delivering 95.8% reliability with 1.44 a.u. alignment time, resulting in the best success rate while being nearly as fast as the fastest method. Variable Gradient achieves the absolute fastest alignment (1.18 a.u.) but with 5.5% lower reliability (90.3%), making it suitable only for applications tolerating higher failure rates. Under realistic production conditions with uncompensated hysteresis (HS-H), Fixed Gradient maintains its advantage (95.8% reliability, 3.32 a.u.), while Global Bayesian degrades significantly (88.9% reliability, 4.29 a.u.). Statistical analysis using data profiles validates these methods for high-volume PIC manufacturing, with the Eclipse Dynamic system demonstrating per-die optical alignments in sub-second timescales using open-loop control hardware. Full article

MXenes are an emerging class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides with a unique combination of mechanical, electrical, and thermal properties. While MXenes have been extensively studied in electrochemical and materials science contexts, their mechanical behavior and engineering relevance remain comparatively underexplored. This paper provides a mechanically focused synthesis of MXene research, connecting structure, synthesis, processing, mechanical properties, and functional performance to engineering applications. Emphasis is placed on the tunability of tensile, elastic, shear, and thermomechanical properties through controlled variation of composition, surface terminations, and defects. Comparisons with graphene are used to clarify performance trade-offs and application-specific advantages. Key challenges, including environmental stability, moisture sensitivity, durability, scalability, cost, and integration with conventional engineering materials, are critically examined alongside current mitigation strategies. Applications in structural composites, mechanical reinforcement, energy storage, electromechanical systems, and MXene-based sensors and actuators are discussed to demonstrate practical relevance. By framing MXenes as engineerable materials rather than isolated nanomaterials, this work serves as a technical reference and entry point for mechanical engineers and interdisciplinary researchers seeking to design and deploy MXenes in advanced engineering systems. Full article

Achieving simultaneous trajectory accuracy and dynamic stability is challenging for four-wheel independent drive (4WID) electric vehicles under near-limit conditions. To effectively resolve this internal control conflict, this paper proposes a novel normalized stability index that accurately quantifies real-time instability risks. Based on this index, a hierarchical adaptive coordinated control architecture is developed, utilizing sliding-mode control for active front-wheel steering to follow trajectories and a fuzzy-logic yaw moment controller to maintain stability. To prevent over-control in safe driving regions, an adaptive weighting mechanism seamlessly adjusts the stability interventions according to the proposed index. Hardware-in-the-loop (HIL) experiments demonstrate that the proposed method lowers sideslip risks on low-adhesion tracks. During a variable-curvature slalom, it reduces the lateral RMSE by 15.08% and decreases the maximum additional yaw moment from 118 N·m to 32 N·m, thereby mitigating excessive control effort, minimizing steering conflicts, and structurally improving the actuation efficiency of the 4WID system. Full article