最新刊期
- 摘要：ObjectiveThe gear drive device of urban rail trains adopts splash lubrication method. To study the influence of lubrication and cooling characteristics on the transmission efficiency and service life of gearboxes under splash lubrication mode, reveal its coupling mechanism, and meet the engineering application development needs of transmission systems.MethodsFirstly, based on the improved semi implicit method of moving particles, a simulation model of the splash lubrication flow field in the gearbox was constructed, and a second-order least squares model was introduced to improve the calculation accuracy; Secondly, a thermal flow coupled temperature field simulation model of the gearbox was established by combining the thermal network method and finite element method. The focus was on studying the influence of the input speed and initial oil level height of the gearbox on the oil stirring power and system lubrication and cooling characteristics. The accuracy of the temperature field simulation prediction model of the gearbox was verified through tests.ResultsResults indicate: oil churning power loss increases exponentially with rotational speed; the gearbox convective heat transfer coefficient continuously increases with rising oil level, the larger the convective heat transfer coefficient, improving system cooling performance; minimal temperature rise in gears and bearings occurs at 1 900 r/min with medium oil level (262 mm below low-speed wheel centerline); simulated bearing and oil sump temperatures align with test data, with relative error below 8%. This research provides theoretical foundations for optimizing urban rail train gearbox design, offering significant engineering value for ensuring subway operational safety.关键词：Gearbox;Splash lubrication;Temperature field;Oil churning loss;Urban rail train2|1|0更新时间：2026-05-12
- 摘要：ObjectiveTo address the challenge of insufficiently capturing critical degradation information in the performance degradation assessment (PDA) of rotating machinery components such as rolling bearings, this study proposes an adaptive optimized feature fusion method based on the Ivy algorithm (IVY). The aim is to construct a health indicator (HI) that more accurately reflects the health status of rolling bearings.MethodsFirstly, multidimensional features were extracted from vibration signals collected throughout the full lifecycle of rolling bearings, and the correlation, monotonicity, prognosability, and robustness were quantitatively analyzed. Secondly, the entropy weighting method was employed to linearly weight these indicators to construct a composite evaluation index, from which higher-scoring features were selected as the preferred set. Finally, the IVY algorithm was applied to adaptively fuse the selected features, yielding the ultimate HI.ResultsTest results demonstrate that the constructed HI can precisely capture the critical evolutionary turning points during the entire lifecycle of rolling bearings. Compared with single-feature-based indicators, the proposed HI exhibits superior performance in correlation, prognosability, and robustness, thereby verifying the effectiveness and reliability of the proposed method for health assessment and preventive maintenance of rolling bearings.关键词：Rolling bearings;Performance degradation assessment;Ivy algorithm;Adaptive optimized feature fusion;Health indicator （编辑：刘欢欢）12|0|0更新时间：2026-05-11
- 摘要：ObjectiveTo address the problems of a single-objective optimization easily falling into local optima and the insufficient coordination between the collision detection and the planning in the obstacle avoidance trajectory planning for dual-arm robots, an adaptive multi-objective particle swarm optimization algorithm was proposed.MethodsThe kinematic model was established by using the D-H parameter method. Trajectory planning in the joint space was carried out by means of the quintic polynomial interpolation. Accurate collision detection was achieved by combining the oriented bounding box method, the separating axis theorem, and continuous collision detection. The path length, collision risk, and motion smoothness were taken as optimization objectives. The weights and algorithm parameters were dynamically adjusted, and the final strategy was selected according to the environmental risk classification.ResultsThe results show that the adaptive multi-objective particle swarm optimization algorithm exhibits the fast convergence speed and the high precision. After optimization, the numbers of changes in the joint angular velocity and the angular acceleration are significantly reduced, and joint impact is obviously decreased. Under both no-load and load conditions, the end-effector position repeatability satisfies the accuracy requirements, and all joint velocities remain within the safe constraint ranges. The proposed algorithm achieves an upgrade from “post-collision replanning” to “active prevention”, effectively reducing joint energy consumption and damage risk, and improving motion smoothness and service life.关键词：Dual-arm robot;Trajectory planning;Polynomial interpolation method;Collision detection;Multi-objective particle swarm optimization algorithm （编辑：贾文倩）17|10|0更新时间：2026-04-30
- 摘要：ObjectiveTo address the issues of parameter optimization and prediction accuracy of the surface roughness of spiral bevel gears, and to overcome the limitations of traditional methods in effectively handling complex nonlinear relationships and the influence of multiple variables, machine learning model is used to predict the surface roughness of the spiral bevel gears.MethodsFirstly, based on the spiral bevel gear grinding test dataset, decision tree (DT), support vector machine (SVR), and artificial neural network (ANN) methods are applied to construct roughness prediction models for the convex and concave surfaces of spiral bevel gears, and the prediction results of the three machine learning models are compared. Secondly, based on this, a multiple linear regression method is used to derive a tooth surface roughness prediction formula that considers the processing parameters of spiral bevel gears. Finally, the contribution of each input feature to the predicted tooth surface roughness is analyzed using the machine learning model explanation tool (SHAP), providing theoretical support for the application of machine learning in high-performance gear manufacturing.ResultsThe results show that the DT and SVR exhibit underfitting and overfitting, respectively, leading to poor prediction performance. The ANN accurately fits the data and predicts tooth surface roughness with high precision, but its computational efficiency is relatively low. The average relative errors in predicting the roughness of the convex and concave surfaces of the spiral bevel gear are 3.5％ and 6.09％, respectively. The influence of the input processing parameters on the predicted tooth surface roughness follows the order of grinding speed, grinding depth, and generating speed.关键词：Tooth surface roughness prediction;Spiral bevel gear;Grinding;Machine learning;Hyperparameter;Model interpretation （编辑：刘星泽）11|4|0更新时间：2026-04-30
- 摘要：ObjectiveThe cycloid gear is a core component of the RV reducer, and its high-efficiency and precision machining methods are crucial for ensuring the performance of the reducer. In view of this, the basic principle methods of hobbing and grinding for the cycloid gear are proposed.MethodsFirstly, the meshing equation was solved through the principle of helical surface formation and spatial coordinate transformation, and geometric motion models of the closed tooth profile curve of the cycloid gear, the worm cutter, and tooth-direction modification were established. Secondly, the principle prototype of the hobbing and grinding machine is constructed using VERICUT software. Through the motion simulation of the formed surface and comparison with the theoretical surface, the deviation is less than 0.004 mm.ResultsThrough the hobbing processing test, the correctness of the established theoretical model and the feasibility of the worm cutter hobbing and grinding processing technology are verified. This lays a theoretical and practical foundation for the high-efficiency machining of the continuous tooth profile of the cycloid gear and three-dimensional topological modification.关键词：Cycloidal gear;Worm-tool;Lengthwise modification;Gear hobbing;Gear grinding （编辑：刘星泽）6|7|0更新时间：2026-04-30
- 摘要：The helicopter transmission system is the key source of cabin noise, which significantly affects the flight quality and ride comfort. Systematically combing its vibration/noise suppression technology can provide technical basis and path reference for engineering design, system integration and localization replacement. This article provides a review of the research progress on vibration/noise suppression technology for helicopter transmission systems both domestically and internationally. Passive vibration suppression techniques (including structural optimization, damping, absorption, and isolation) and active vibration suppression techniques (covering actuators and active control algorithms) have been elucidated in this review. The research status of vibration suppression technology for transmission systems of special configurations of helicopters with high-speed flight characteristics, such as coaxial reverse twin rotor helicopters and tilt rotor helicopters, has been summarized. At the same time, the vibration reduction mechanism of new transmission components such as magnetic gears, ceramic bearings, composite shafts, and casings has been explored, as well as the research progress of revolutionary electric drive technologies such as electric tail rotor and fully electric drive. Finally, based on the current research status in China, suggestions are proposed for multidimensional optimization of active vibration suppression technology, technological innovation to promote the upgrading of new transmission components, and the development of new energy helicopters, in order to enhance the international competitiveness of China's helicopters.关键词：Helicopter transmission system;Vibration;Noise;New-type transmission components;Electric drive9|5|0更新时间：2026-04-30
- 摘要：ObjectiveThe encased differential planetary gear train of a coaxial helicopter consists of numerous components with varying failure probabilities. Identifying weak components and potential failure modes is critical for implementing targeted measures, such as structural optimization or material substitution, to enhance the system's service life and reliability.MethodsFirstly, a comprehensive risk assessment model was developed by integrating fuzzy set theory with the technique for order preference by similarity to an ideal solution (TOPSIS). Secondly, trapezoidal fuzzy numbers were utilized to construct a robust fuzzy evaluation matrix, and a hybrid weighting scheme combining the analytic hierarchy process (AHP) and the entropy weight method (EWM) was implemented to determine objective and subjective index weights. Finally, an expert scoring framework was established, and a ranking index was calculated for each component to prioritize failure risks.ResultsThe analysis results demonstrate that among the gear components, the sun gear of the differential stage exhibits the highest risk index, identifying it as the weakest part of the system. The primary failure modes are determined to be tooth surface wear and tooth root cracks. This study offers a quantitative theoretical reference for the reliability design and maintenance of complex aviation transmission systems.关键词：Fuzzy set theory;AHP;TOPSIS;Comprehensive risk assessment method;Encased differential planetary gear train （编辑：李立）11|7|0更新时间：2026-04-30
- 摘要：ObjectiveAiming at the problem that the gear transmission system of aero-engines is prone to traveling wave resonance under complex operating conditions, which further restricts high-reliability lightweight design, a vibration avoidance optimization study was carried out on the gear web structure.MethodsFirstly, a surrogate model for gear modal frequencies was constructed based on the Kriging interpolation method and Bayesian hyperparameter optimization, which was used to replace high-cost numerical analysis and efficiently predict the influence of structural parameters on natural frequencies. Secondly, taking the web thickness ratio and rim ratio as design variables, a mathematical optimization model was established with the objectives of minimizing system mass and maximizing comprehensive mesh stiffness. Then, the surrogate model was embedded into the Non-dominated Sorting Genetic Algorithm Ⅲ (NSGA-Ⅲ) framework, and multiple constraints including resonance speed margin were imposed to conduct multi-objective iterative optimization. Finally, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was adopted to comprehensively evaluate the Pareto front solutions and select the optimal structural scheme.ResultsThe results show that the coefficients of determination (R²) of the established surrogate model for the first three nodal diameter natural frequencies of gears reach 96.7%, 94.7%, and 98.8%, respectively, indicating that the prediction accuracy satisfies engineering design requirements. After optimization, the resonance points of six gears with traveling wave resonance risks under continuous and high-speed operating conditions are all effectively avoided. Compared with the initial design scheme, the total mass of the gear set is reduced by 14.4%, while the contact and bending fatigue safety factors of each gear still meet the strength standards of being greater than 1.25 and 1.5, respectively.关键词：Aero-engine;Accessory gearbox;Surrogate model;Traveling wave resonance;Lightweight design4|5|0更新时间：2026-04-30
- 摘要：ObjectiveSplines are important connectors in aviation power transmission systems, and are affected by manufacturing errors, assembly errors or working loads, and often occur in parallel misalignment, angular misalignment and comprehensive misalignment, which affects the meshing length and bearing capacity of each tooth of the spline. In order to improve the stability of the transmission system and reduce the failure rate of aviation splines, it is necessary to analyze the dynamic meshing stiffness characteristics of misaligned splines.MethodThe dynamic model of the aviation spline-rotor system was established, the time-varying meshing length of the spline was solved, and the slicing method and the Ishikawa method were combined to obtain the stiffness of the spline single tooth meshing under different dislocation conditions and the dynamic response of the system was solved.ResultThe results show that the change amplitude of spline single-tooth meshing stiffness and the dynamic response of the rotor system increase when the static parallel dislocation and static angular dislocation amount are increased. The static parallel dislocation amount remains unchanged, and the static angular dislocation amount changes, and the change of spline meshing stiffness and the dynamic response of the rotor system is not obvious. The static angular dislocation amount remains unchanged, and the static parallel dislocation amount increases, and the spline meshing stiffness and the dynamic response of the rotor system change significantly.关键词：Aero spline;Rotor dynamics;Meshing stiffness;Newmark-Beta method9|8|0更新时间：2026-04-30
- 摘要：ObjectiveAddressing the requirements for high-quality and efficient manufacturing of aviation spur gears, and targeting issues such as incomplete tooth profile filling and excessive forming loads encountered in traditional single-degree-of-freedom forming methods like die forging and extrusion, this study innovatively proposes a multi-degree-of-freedom forming approach for aviation spur gears. This method enhances material flow capacity and reduces forming loads through continuous local loading via a multi-degree-of-freedom rolling die. Simultaneously, it refines the grain structure of the gear and generates continuously distributed metallic flow lines along the tooth profile, thereby improving the gear's strength and fatigue life. This provides a new technological pathway for manufacturing high-strength, high-toughness, and long-life aviation spur gears.MethodsFinite element simulation technology was first employed to investigate the influence of preform geometry on tooth profile filling effectiveness and forming load. Based on this, an optimized preform design method was proposed. The mechanisms of tooth profile filling, Effective strain distribution and evolution, and metallic flow lines evolution during the forming process were further revealed. Subsequently, a Multi-Degree-of-Freedom Near-Net Shape Forming experiment was conducted based on simulation results. Grain size and metallic flow lines of the test specimens were characterized to validate the finite element model and simulation results.ResultsThe results demonstrate that: Frustum-shaped preforms significantly improve tooth profile filling completeness and reduce forming load, enabling the production of fully-filled aviation spur gears. The Multi-Degree-of-Freedom forming method introduces severe plastic deformation into the tooth profile zone, effectively refining grain size and generating continuously distributed metallic flow lines along the tooth contour. Multi-Degree-of-Freedom Near-Net Shape Forming technology achieves high-performance manufacturing of aviation spur gears.关键词：Aviation spur gear;Multi-degree-of-freedom near-net shape forming;Law of plastic forming;High-performance manufacturing;Forming process design （编辑：刘星泽）8|5|0更新时间：2026-04-30
- 摘要：ObjectiveGears are central components of power transmission systems, and their surface integrity fundamentally dictates the reliability and fatigue life of high-end equipment. Ultrasonic vibration-assisted grinding (UVAG) introduces high-frequency energy to mitigate excessive cutting forces and frictional heat accumulation, which are critical challenges in the precision manufacturing of high-performance gears. [Analysis] Through a systematic review of existing literature, this paper firstly delineates the evolutionary trajectory and core technical specifications of gear UVAG equipment. Secondly, it investigates the regulatory mechanisms of ultrasonic vibration on material removal behaviors based on surface integrity characterization methods, such as surface roughness, residual stress distribution, and subsurface damage control. Technical characteristics of different vibration application modes are comparatively analyzed.ConclusionUVAG demonstrates superior capabilities in improving gear surface quality and reducing thermal damage compared to conventional grinding. It provides a robust theoretical foundation for achieving “high precision and long life” in gear manufacturing. [Prospect] Future research should focus on the synergistic optimization of multi-physics fields during the UVAG process and the development of high-frequency, large-scale integrated equipment to meet the requirements of extreme service conditions in aerospace and industrial robotics.关键词：Gear system;Ultrasonic vibration;Grinding process （编辑：李立）8|5|0更新时间：2026-04-30
- 摘要：ObjectiveInternal gear polish honing has the characteristics of improving tooth surface quality and reducing transmission noise, which can effectively improve the service performance and fatigue life of gears. In order to gain a deeper understanding of the surface formation mechanism of internal gear polish honing of aerospace gears and guide the optimization of process parameters, a positive prediction method for the three-dimensional surface roughness of internal gear polish honing was proposed.MethodsFirstly, based on the principles of internal conjugate meshing and abrasive cutting mechanisms, the cutting depth and cutting number of abrasive grains driven by honing process parameters were derived. Secondly, the progressive removal of micro-asperities on the tooth surface by abrasives during honing was equivalently mapped into a "meshing contact-material removal" signal processing operator applied to the 3D height data. Then, through adaptive denoising and morphology-preserving correction of the measured initial tooth surface, the material removal process was simulated. Finally, iterative calculations were performed using Matlab software to obtain the post-honing 3D surface height data and predict the roughness.ResultsValidated by gear honing experiments, the average prediction errors for 12 groups of roughness parameters Sa、Sq and Sz are 6.41%, 5.30%, and 5.86%, respectively, with the maximum error not exceeding 12.76%. The analysis indicates that surface roughness decreases with an increase in honing wheel speed and increases with a decrease in the cutting rate. This research provides a quantitative reference for optimizing process parameters in internal gear polish honing and offers a novel proactive prediction method for the precision machining of complex curved surfaces.关键词：Internal gear polish honing;Aeronautic gear;Surface roughness;Predictive modeling;Abrasive grain6|5|0更新时间：2026-04-30
- 摘要：ObjectiveThe 15Cr14Co12Mo5Ni alloy represents a new generation of low-carbon, high-alloy steels characterized by exceptional strength, elevated-temperature stability, and superior wear resistance, making it widely applicable in high-performance sectors such as aerospace engineering and automotive transmission systems. Magnetic particle inspection (MPI) serves as a critical non-destructive evaluation method for ensuring the structural integrity of components fabricated from this alloy. However, the presence of short rod-shaped magnetic indications frequently complicates defect assessment by introducing non-relevant signals. This study systematically examines the formation mechanism of such magnetic indications, with particular emphasis on their correlation with the alloy’s internal microstructural characteristics, carbide distribution patterns, and forging parameters. The findings provide a scientific foundation for optimizing forging practices, refining grain structure, mitigating excessive dislocation slip bands, and minimizing spurious magnetic indications in quality control processes.MethodsSamples were collected from both the magnetic-indication-displaying and non-displaying regions of the alloy gear shaft hole. By integrating magnetic particle inspection (MPI), scanning electron microscopy (SEM) observation, metallographic analysis, and energy-dispersive X-ray spectroscopy (EDS) analysis, comparative studies were conducted on the morphological characteristics, carbide compositions, and grain structure differences of magnetic indications at both macroscopic and microscopic scales.ResultsComprehensive macroscopic and microscopic investigations reveal that the formation of these magnetic indications is strongly associated with the chain-like clustering of Cr-Mo-rich carbides within the microstructure. These carbide aggregates induce local variations in magnetic permeability, thereby generating magnetic flux leakage fields that promote the accumulation of magnetic particles during inspection. Further analysis has elucidated a sequential microstructure evolution chain leading to the development of short rod-shaped magnetic traces: "coarse grains → dislocation slip bands → Cr/Mo segregation → interfacial directional precipitation → carbide banding → magnetic permeability gradient → magnetic particle accumulation."关键词：Short rod-shaped magnetic trace;Magnetic permeability gradient;Cr-Mo based carbides;Dislocation slip band;Microstructure evolution chain;Forging process （编辑：刘星泽）6|5|0更新时间：2026-04-30
- 摘要：ObjectiveAiming at the struts, the key components for the installation and support of helicopter main reducers, the research progress of conventional struts and intelligent struts is analyzed in combination with the development trend of strut structures. [Analyses] The mounting and support layouts of helicopter main reducers are divided into flange type, strut type and other structural forms. The structural characteristics and application scope of each layout are summarized and analyzed. Combined with typical aircraft cases, the application status of different mounting and support layouts in conventional single-rotor and coaxial twin-rotor helicopters is concluded. [Outlooks] The collaborative optimization of lightweight materials and intelligent algorithms is proposed as the key approach to improve the dynamic performance of the support system in the future.关键词：Helicopter main reducer;Flange type;Strut type;Periodic strut;Smart strut （编辑：刘星泽）7|5|0更新时间：2026-04-30
- 摘要：Ignoring the steering trapezoidal mechanism or assuming that the steering angles of the left and right front wheels are the same will reduce the accuracy of vehicle path tracking, steering aligning torque calculation and steering trapezoidal mechanism optimization.In this paper, the transmission ratio function of the steering trapezoidal mechanism will be constructed and the steering angles of the left and right front wheels will be calculated to reveal the reasons for the steering angle differences caused by the steering trapezoidal mechanism.Through the structural analysis of the steering trapezoidal mechanism, its motion is divided into the spatial motion of the wheel-kingpin and the planar motion of the Ackerman linkages. Projecting the spatial geometric position between the wheel and the kingpin, calculating the relationship between the kingpin and the steering angle using the spatial vector, the wheel-kingpin transmission ratio is derived.The equivalent steering trapezoid is projected from the Ackerman linkages, and its transmission ratio function is derived by constructing the auxiliary angle of the steering trapezoid and the triangle of the Ackerman linkages. The total transmission ratio function is composed of the wheel-kingpin transmission ratio, the steering gear transmission ratio and the steering trapezoidal transmission ratio. Its correctness and accuracy are verified by comparing the Matlab/Simulink numerical simulation and the Adams/Car motion simulation results. The results show that the variation of the long side of the Ackerman linkages triangle is the main reason for the inconsistent steering angles of the front wheels; within the steering range, 0°~27°, the absolute value of the maximum relative error of the steering angle calculated by the total transmission ratio function shall not exceed 3.21%.关键词：Wheel-kingpin motion;Ackermann linkage system;Steering angle difference;Steering transmission mechanism;Steering simulation6|11|0更新时间：2026-04-24
- 摘要：ObjectiveAiming at the problems of insufficient research on the vibration characteristics of the dual planetary speed-increasing gearbox for high-speed turbine starters, complex internal excitations in the dual planetary gear structure, unclear contribution mechanism of the gearbox vibration, and ambiguous laws of dynamic response peaks and resonance under extreme high-speed operating conditions, taking the dual-planetary speed-increasing gearbox used in the rotor strength test of a high-speed turbine starter as the research object, its vibration characteristics were analyzed.MethodsFirstly, a rigid-flexible coupling dynamic model of the transmission system, including a flexible housing, was established using simulation software. Secondly, a modal analysis of the system was conducted to obtain the first 15 natural frequencies and modal shapes, and the resonance risk under operating speeds was assessed using a Campbell diagram. Finally, the dynamic transmission error, dynamic contact load, and housing surface vibration acceleration of the system were analyzed.ResultsThe research results indicate that the speed-increasing gearbox effectively avoids resonance zones under both operating and maximum speeds. The dynamic transmission error and dynamic contact load exhibit peak values within the input shaft speed range of 12 000-13 500 r/min, with the most significant vibration observed in the Y-direction of the housing. The accuracy of the simulation model is validated through vibration tests, with the relative error between test and simulation results being within 5%. This demonstrates that the developed model can effectively predict the vibration behavior of the system, providing a basis and practical reference for the dynamic design and optimization of similar high-speed planetary gearboxes.关键词：Planetary gear transmission;Vibration characteristic;Rigid-flexible coupling model;Modal analysis;Test verification （编辑：贾文倩）8|5|0更新时间：2026-04-13
- 摘要：ObjectiveAerospace gears have strict requirements for surface integrity. Ultrasonic vibration-assisted grinding (UVAG) can enhance the residual compressive stress and fatigue resistance of gear surfaces, but the thermal-mechanical-microplastic coupling mechanism remains to be further clarified. Therefore, a crystal plasticity finite element model (CPFEM) considering both ultrasonic vibration and thermal-mechanical coupling was established to predict the residual stress on the gear surface and reveal the ultrasonic control mechanism.MethodsA gear surface following coordinate system and grinding contact geometry were constructed, and models for friction attenuation, tangential grinding force, and transient heat flow under UVAG conditions were derived. The ultrasonic softening term and temperature softening term were introduced into the CPFEM, and the material parameters of 12Cr2Ni4A alloy steel were calibrated to establish a surface/depth dual-scale polycrystalline model. Simulations under different grinding parameters and conditions were conducted in the Abaqus-UMAT framework. An UVAG test platform was built, and the grinding temperature rise was verified by embedded thermocouples. The residual stress on the gear surface and at different depths was measured by the X-ray diffraction (XRD) layer-by-layer peeling method to validate the model.ResultsUnder the reference condition, the model predicts a peak residual compressive stress of approximately -369 MPa on the gear surface and about -50 MPa at 100 μm, with a deviation from the XRD measurement of no more than 20%. Under different conditions, the average verification error of the surface is approximately 21%, and the trend of the simulated values is consistent with the test values. Compared with conventional grinding, the peak residual compressive stress under UVAG conditions increases by 20%-30%, and the effective depth of action increases by about 50%. The results show that UVAG can reduce the average Taylor factor and increase the slip activity by suppressing frictional heating and promoting multi-slip coordination and dislocation proliferation, thereby reconstructing the cross-scale stress field. The established model can be used for residual stress prediction and process parameter optimization of UVAG in aerospace gears.关键词：Aerospace gear;Crystal plasticity finite element model;Ultrasonic vibration-assisted grinding;Thermal-mechanical coupling;Residual stress （编辑：贾文倩）5|5|0更新时间：2026-04-13
- 摘要：ObjectiveIn response to special working conditions such as complex shapes of specific bricks and limited operating space in refractory bricklaying, traditional methods exhibit shortcomings in plastering irregularly shaped brick surfaces, including low planning efficiency, poor trajectory smoothness, and high path cost. To address these issues, an improved rapidly-exploring random tree (RRT) algorithm was proposed to study the path planning problem for plastering robotic arms.MethodsPartitioned Gaussian sampling was employed to enhance search focus on critical areas. Gravity-based dynamic step size adjustment was adopted to enable adaptive exploration in confined spaces. Triangular inequality pruning and cubic B-spline optimization were introduced to eliminate redundant nodes and improve trajectory smoothness.ResultsSimulation results demonstrate that the improved RRT algorithm outperforms comparison algorithms in planning time, path length, path node count, and iteration count. Physical tests validate the improved RRT algorithm’s capability for stable obstacle avoidance and plastering operations in masonry environments. Compared to traditional RRT, RRT*, Bias-RRT, and RRT-Connect, its planning time decreases by 70.80%, 80.54%, 29.12%, and 22.24%, respectively, while reducing path length by 31.26%, 3.52%, 22.62%, and 30.10%, respectively, demonstrating excellent engineering applicability.关键词：Plastering robotic arm;Path planning;Improved RRT algorithm;Partitioned Gaussian sampling;Gravity-based dynamic step size adjustment （编辑：贾文倩）6|5|0更新时间：2026-04-13
- 摘要：ObjectiveTo address the challenges of complex structure, insufficient modeling accuracy, and suboptimal transmission performance in coaxial magnetic gear (CMG) design, a transmission-characteristic-based modeling and multi-objective optimization method was proposed to provide insights for CMG development and optimization.MethodsFirstly, the magnetic field of the CMG was computed using the subregion method, with the analytical solution for the air gap magnetic field verified through two-dimensional simulation. Secondly, theoretical calculation, finite element simulation, and test method were employed to investigate its torque-angle characteristics. End leakage magnetic effects were analyzed based on 3D simulations, and speed-efficiency relation curves were obtained under multiple operating conditions. Finally, the CMG was optimized using the non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ) to derive structural parameters with superior transmission performance.ResultsThe theoretical calculation torque values show extremely high consistency with the 2D simulation torque values, while the test torque values align even more closely with the 3D simulation torque values. Compared to the theoretical calculation and 2D simulation torque values, both test and 3D simulation torque values are significantly reduced. This discrepancy stem from the end effects of the permanent magnets. The CMG demonstrates a marked improvement in performance under the final parameters, achieving the optimization objective.关键词：Coaxial magnetic gear;Subregion method;Electromagnetic torque;Transmission characteristic;Finite element simulation;Multi-objective optimization19|31|0更新时间：2026-04-08
- 摘要：ObjectiveTo support the technological innovation and application expansion of integrated servo joints for humanoid robots, the structural characteristics of rotary joints and linear joints as well as their application scenarios in typical humanoid robots at home and abroad were reviewed, the driving methods of integrated linear servo joints were summarized, and the key technologies and future development directions of integrated electric-driven linear servo joints were explored.SignificanceAs the core driving component for high-precision motion and dynamic force-position response of robots, the performance of integrated servo joints directly determines the operational capability and reliability of robots in complex environments, and relevant research provides key technical support for the development of high-performance joints and the industrial upgrading of intelligent robots. Through literature combing, typical case analysis and technical induction, the configuration design, manufacturing of core transmission components and high-frequency response control were identified as the core technical points, and high integration and lightweight were pointed out as the main development trends.关键词：Integrated linear servo joint;High integration;Electric drive;High frequency response control111|200|0更新时间：2026-03-09
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