Abstract: To investigate the influence of workpiece-tool position errors on the tooth surface during the grinding of RV reducer cycloidal gears using a worm wheel, the study is based on meshing theory. Starting from the tooth profile equation of the worm wheel's normal cross-section, the meshing equation for grinding cycloidal gears with the worm wheel is derived. By introducing coordinate transformation matrices that account for installation angle deviations of the worm wheel, eccentricity of the cycloidal gear workpiece, and flatness deviations, the tooth surface equation of the cycloidal gear under error conditions is calculated. The correctness of the theory and analysis is verified through VERICUT grinding simulation. Through comparative analysis, the impact patterns of various errors on the tooth surface are obtained, which can provide a theoretical basis for error compensation in the grinding of cycloidal gears. Read More

Abstract: In current permanent magnet synchronous motor (PMSM) control systems,the traditional PI algorithm is commonly employed for motor control and regulation.However,this approach suffers from issues such as prolonged settling time and excessive overshoot.To address these problems,a PMSM control design based on Active Disturbance Rejection Control (ADRC) is proposed.Furthermore,to enhance the motor's operational stability,disturbance rejection capability,and reduce control costs, three speed control strategies for PMSMs are designed based on Nonlinear Active Disturbance Rejection Control (NLADRC),Linear Active Disturbance Rejection Control (LADRC), and PI controllers.By constructing simulation models and conducting simulation experiments,it is demonstrated that,compared to the traditional PI algorithm and LADRC,the NLADRC-based strategy achieves a smoother speed curve,shorter settling time,and smaller overshoot,exhibiting superior real-time performance and robustness.This meets the requirements of industrial control applications,verifying that the NLADRC-based control strategy designed in this paper offers optimal motor response and tracking characteristics.The nonlinear active disturbance rejection control technology successfully enables closed-loop speed control of permanent magnet synchronous motors. Read More

Abstract: With the rapid advancement of Industry 4.0 and smart manufacturing, traditional fixed processing and inspection equipment can no longer meet the flexible manufacturing demands of large-scale and complex-shaped components. Mobile processing and inspection robots, with their high adaptability and efficiency, have become critical equipment in modern workshops. This paper focuses on analyzing two mainstream solutions—visual-inertial fusion (VI-SLAM) and laser-visual fusion—emphasizing the advantages of multi-sensor fusion in enhancing robustness and precision. It provides a detailed exploration of the visual SLAM framework and algorithmic advancements based on feature points and deep learning. Additionally, the study investigates the collaborative design of global path planning and local obstacle avoidance algorithms, aiming to offer technical references for reliable autonomous navigation of mobile robots to preset workpoints in known environments. Read More

Abstract: To address the issues in traditional laser cladding systems—such as reliance on manual experience for process parameters, severe data silos, and the lack of real-time monitoring and closed-loop control—this study develops an intelligent manufacturing cloud platform system based on Digital Twin (DT) technology. Firstly, a parametric virtual simulation environment is established by developing custom process components within the Siemens Plant Simulation DT platform. Secondly, real-time data interaction between Plant Simulation and the underlying PLC is achieved via the OPC UA protocol, enabling millisecond-level data acquisition from physical equipment and synchronization with the virtual model. Finally, the self-developed Industrial Internet cloud platform is integrated using the MQTT protocol, resulting in a cloud system comprising three core modules: equipment management, real-time monitoring, and historical data traceability. This research realizes full-process data integration and real-time interaction among physical equipment, the digital twin, and the cloud platform. The developed cloud platform enables remote, real-time status monitoring and visualization of the laser cladding process, thereby providing critical technical support for intelligent process optimization and cross-regional collaborative management. Read More

Abstract: To meet the demand for low-cost, highly reliable, and easily programmable loading and unloading equipment in automated CNC machining production lines, this paper designs a three-axis gantry-type loading and unloading manipulator. The whole machine adopts a gantry frame and a Cartesian coordinate structure, with stepper motors and synchronous belts as the transmission scheme, and is equipped with a pneumatic clamping end effector to realize the automatic transfer of workpieces between machine tools and silos. The control system is built with a PLC, stepper motor drivers and a touch screen, supporting touch screen programming, point-to-point motion, signal input and output control, delay control and other functions. The human-machine interaction system adopts a touch screen for visual operation, reducing the threshold of debugging and use. Through lightweight structural design, modular component design and simplified programming design, on the premise of ensuring a repeated positioning accuracy of ±0.1 mm and stable and reliable operation, the overall cost and deployment cycle of the machine are significantly reduced. Prototype tests show that the manipulator meets the requirements of flexible processing for small and medium batch production and has high engineering application value. Read More

Abstract: Under the "dual carbon" framework, the pressure energy benefit of recovering natural gas pressure regulation loss is significant. This article proposes an optimized design for a multi-stage culvert impeller, featuring a relatively simple structure, small footprint, and low leakage risk, specifically tailored for existing pressure difference power generation technology. Through optimization of the number of stages and spacing, it is confirmed that the theoretical power of a three-stage impeller increases by 31.8% compared to a single-stage impeller under a spacing of twice the impeller radius, providing an efficient and low-leakage solution for small and medium-sized pressure energy recovery. Read More

Abstract: Natural gas pressure difference power generation is an innovative low-carbon energy technology that integrates energy efficiency, environmental protection, and economic benefits. This paper proposes a ducted natural gas pressure energy power generation device using an axial-flow turbine. The geometric parameters of the rotor and stator blades of the axial-flow turbine are derived through a one-dimensional design method. Additionally, the flow characteristics and blade load distribution of this blade profile are analyzed, and directions for further optimizing the turbine to enhance its output power are put forward. Read More

Abstract: Latent heat storage systems are limited by the low thermal conductivity of phase change materials (PCMs), resulting in prolonged charging and discharging times. To address the issues of a single heat conduction path and thermal coupling imbalance in triplex-tube heat exchangers (TTHX), this study proposes an optimized TTHX with internal and external conductive connections. By integrating fins penetrating the tube walls at the bottom of both annular channels, a direct metallic thermal connection node is established, enabling rapid thermal equilibrium between the inner and outer HTFs. Numerical simulation results show that at an inner-to-outer ratio of 0.7, the melting time is reduced by 35.2%; at a ratio of 0.5, the solidification time is 58.9% shorter than that of the novel TTHX at the same ratio and 41.8% shorter than its optimal solidification time. The performance enhancement is attributed to multi-path heat transfer and the full development of two independent natural convection zones. This study achieves a shift from quantitative enhancement to targeted point-specific enhancement, providing new insights for the design of efficient latent heat storage systems. Read More

Abstract: Casing deformation is a major constraint in the efficient development of shale gas horizontal wells during hydraulic fracturing. This study investigates the deformation characteristics and influencing factors in shale gas wells of the Zigong block. A finite element model of the shale–cement sheath–casing system for deep shale gas wells was established based on shale swelling mechanics. Through numerical simulations, the mechanism of casing deformation induced by shale swelling during hydraulic fracturing was determined, and the casing deformation patterns under the combined effects of shale swelling and cementing quality were revealed. Results show that shale swelling significantly increases casing compressive stress and can induce severe deformation. The casing stress distribution along the wellbore axis is strongly affected by the extent of shale hydration. In addition, cement sheath voids and elliptical geometry significantly affect casing stress. Elliptical cement sheaths exacerbate casing elliptical deformation, while cement sheath voids cause localized outward bulging of the casing. The orientation of cementing defects influences the casing's stress and deformation extent. Based on these findings, targeted strategies are proposed to mitigate deformation risks. This study provides new insights into casing failure mechanisms and offers theoretical guidance for fracture design and well integrity management in shale gas reservoirs. Read More

Abstract: To enhance the surface wear resistance of GH4169 nickel-based superalloy components under extreme service conditions, this study investigates a laser-clad JG-2/cBN composite coating. The composite coating was fabricated on the GH4169 substrate using a high-power fiber laser with optimized processing parameters (laser power: 1.5 kW, scanning speed: 5 mm/s, powder feed rate: 15 g/min). The JG-2 nickel-based alloy powder was mechanically mixed with cubic boron nitride (cBN) particles at a 1:1 volume ratio as the cladding material, with a pure JG-2 coating prepared under identical conditions as the control group. The microstructure, phase composition, microhardness, and tribological properties of the coatings were systematically characterized. Friction and wear tests were conducted using a ball-on-disc configuration under a 50 N load at room temperature for 60 minutes. Three-dimensional laser confocal microscopy, wear volume measurement, and two-dimensional profilometry were employed to evaluate wear track morphology and wear mechanisms. Results demonstrate that the JG-2/cBN composite coating exhibits superior tribological performance compared to the monolithic JG-2 coating. The friction coefficient of the composite coating remained stable between 0.25 and 0.30 throughout the test, significantly lower than that of the JG-2 coating (approaching 0.9 with severe fluctuations). The maximum wear depth decreased from approximately 97 μm (JG-2 coating) to 20 μm (composite coating), while the wear volume was reduced by approximately 80.1% (from 188,881,542 μm³ to 37,626,995 μm³). Two-dimensional wear scar profiles revealed shallower and narrower grooves with smoother contours for the composite coating, indicating suppressed plastic deformation and material detachment. The incorporation of cBN hard particles enhances the load-bearing capacity, micro-cutting resistance, and interfacial stability of the coating, effectively mitigating adhesive wear, plowing, and oxidative wear … Read More