Abstract: Intelligent manufacturing lines constitute a complex system characterized by the integration of multiple technologies, the intersection of various disciplines, multi-dimensional integration, and the interaction of numerous components. Currently, the internal environment of intelligent manufacturing workshops, processing technologies, and production processes all exhibit a high degree of complexity, and the diversity of underlying mechanical equipment is particularly notable. Compared to traditional manufacturing assembly lines, the process coupling between equipment in flow-type production lines is tighter and more significant. Therefore, this paper undertakes digital twin modeling of intelligent manufacturing lines from five aspects: geometry, motion, data, communication, and control. This approach aims to achieve precise and detailed mapping of the physical entity production line's processing operations. Read More

Abstract: With the development of large-scale and high-density aquaculture, higher requirements have been put forward for the effectiveness of water oxygenation. In response to the problems of low oxygenation efficiency and high energy consumption of oxygenation devices on the market, a new type of oxygenation device was designed based on the theory of microbubble generation technology, and its oxygenation performance was studied through clear water oxygenation experiments. The experimental results show that under the action of microbubbles, the oxygenation device has the best oxygenation effect when the water flow rate and oxygen flow rate are 2.4m3/h and 0.4L/min, respectively. After adding oxygen to clean water with an initial oxygen concentration of 5.3mg/L through the device, the oxygen concentration increased to 11.2mg/L, reaching a supersaturated state. The oxygen absorption rate was 41.2%, and the oxygenation capacity was 6.68kg/h. Compared to traditional oxygenation machinery, under the premise of achieving the same oxygenation effect, the oxygenation time is shorter, effectively improving the oxygenation efficiency Read More

Abstract: When the active power of a Virtual Synchronous Generator (VSG) is unbalanced, the frequency will fluctuate significantly. Based on this, this article proposes an adaptive model predictive control method. By introducing a hyperbolic tangent function to construct an adaptive moment of inertia that includes frequency change and frequency change rate to provide the inertia for the island microgrid system, and the predicted model is updated in real-time; At the same time, model predictive control is used to calculate the optimal power reference value of VSG, strengthening the power support of VSG. The results indicate that under joint control improves the frequency regulation capability of VSG units and further enhances the system frequency performance, and the frequency deviation reduces from 0.15Hz to 0.05Hz, and the frequency change rate reduces from 0.58Hz/s to 0.5Hz/s. It is proved that the proposed control strategy can effectively suppress the maximum frequency offset and maximum frequency change rate during power fluctuations. Read More

Abstract: The purpose of this study is to provide a high gear ratio reducing pump jack system, utilizing the characteristics of high transmission ratio and precision of harmonic drives, in order to improve the efficiency of low-permeability oil field extraction. A comparison was made between the new system and the conventional walking beam pump jack. The results showed that at a stroke length of 1.5 m and pumping frequencies of 4.5 min-1, 3.5 min-1, 2.5 min-1, 1.5 min-1, and 0.5 min-1, the maximum acceleration of the suspended load in the harmonic reducing pump jack was reduced by 20.79% compared to the conventional walking beam pump jack. Read More

Abstract: Aiming at the problem of inaccurate prediction of spatial-temporal distribution of electric vehicle charging load due to insufficient consideration of vehicle-road-station-network interaction, a prediction model of spatial-temporal distribution of electric vehicle charging load based on gravitation model was proposed. Firstly, considering road network traffic flow and ambient temperature, the relationship between external environment and energy consumption of electric vehicles is analyzed. Secondly, considering the influence of external environmental factors such as temperature on user travel, a travel chain model based on travel intention modification is established. Finally, the selection model of EV charging station based on gravitation model is established. The simulation results show that the proposed model can take into account the interaction of EV, road network, charging station and power grid, and accurately calculate the spatio-temporal distribution of EV charging load, and analyze the characteristics of EV charging demand load in multi-regions. Read More

Abstract: This paper summarizes the research hotspot of underactuated mechanical system in nonlinear control field, and emphasizes its wide application in practical engineering, including space vehicle, inverted pendulum and navigation system. The Chinese government has supported the construction crane industry through a series of policies and regulations, providing guidance for its safe production and technical specifications. In the context of social development, the application demand of bridge gantry cranes in narrow environments is increasing, and the future development trend will focus on the direction of intelligence, science and technology and humanization. In recent decades, the research results on the positioning and pendulum of bridge crane at home and abroad are divided into open loop and closed loop control methods, and the control methods are described in detail in this paper. Read More

Abstract: In response to the issues of poor safety and insufficient training equipment in traditional machine tool assembly and disassembly training, this paper proposes a machine tool assembly and disassembly training system based on virtual simulation. The system utilizes Unity 3D to construct an interactive virtual training environment, achieving highly simulated simulations and teaching of the machine tool assembly and disassembly process. Additionally, the system is capable of establishing communication with actual machine tools, achieving bidirectional mapping between digital and physical spaces, allowing learners to observe the dynamic responses of machine tool models through the virtual environment. This virtual-real interaction mechanism enriches the application scenarios of the system, introducing digital twin technology into the virtual simulation of machine tool assembly and disassembly training. This paper also provides a detailed introduction to the design and implementation of core technologies such as the system's overall architecture, scene modeling, and virtual-real interaction, offering significant support for intelligent teaching in machine tool assembly and disassembly. Read More

Abstract: The traditional control of electric spring (ES) is too complex and lack of robustness, as well as the chattering phenomenon and control accuracy of traditional sliding mode control, a second-order terminal sliding mode control based on super twisting algorithm is proposed. In this paper, the phase plane method is used to establish the mathematical model of ES, solve the state space equation, and regard the AC power supply as a simplified error analysis. Then a second-order sliding mode controller is proposed. The controller parameters are solved to obtain the second-order sliding mode control rate, and the stability is verified. Finally, three groups of comparative simulation experiments were set up by Matlab/Simulink, and the effectiveness of the model was verified by considering the voltage mutation caused by the change of power supply and circuit parameters. Compared with the traditional control method, the proposed control strategy not only ensures the voltage stability, but also improves the control accuracy and the performance of suppressing sliding mode chattering, and has better dynamic response ability. Read More

Abstract: Based on the lunar exploration project, a mechanical structure design scheme for a heavy-duty hexapod robot movement system with bounce characteristics was proposed. The materials used were determined by the robot's working environment and performance standards. The mechanical structure of a jumping heavy-duty hexapod robot was designed using SolidWorks 3D modeling software. Based on the analysis of the working modes of the root joint, hip joint, knee joint, and jumping energy storage mechanism, the main components of each joint and jumping energy storage mechanism were designed, and a single leg mechanism was obtained. Based on the special soil structure on the lunar surface, the foot end buffer mechanism was designed, and finite element stress analysis was conducted on the key components of the robot model, proving the rationality of the mechanical structure of a heavy-duty hexapod robot with bounce characteristics. Read More

Abstract: Behind the development of integrated circuits to the current brilliant era is the contribution of Moore's Law, which has guided the development prospects of the industry for a long time. But as transistors continue to shrink in size and thickness, silicon itself approaches its own physical limits and Moore's Law no longer applies. Therefore, scientists are eager to solve this puzzle by introducing new materials, including two-dimensional materials. Molybdenum disulfide has attracted much attention because of its special properties, and the preparation method needs to be studied deeply for large-scale use of molybdenum disulfide. There are many factors that affect the synthesis of single layer molybdenum disulfide, such as the amount of reaction source, air pressure, substrate, reaction temperature of two sources, source heating rate, holding time, relative position between molybdenum source and sulfur source substrate, gas flow, etc. In short, these reaction conditions are summarized, which mainly affect the concentration and reaction speed of sulfur source and molybdenum source in the reaction substrate position. In this paper, the effects of CVD on the quality of single layer disulfide were summarized and its development trend was prospected. Read More

Abstract: In order to examine the temperature field changes of railway roadbed in seasonal frozen areas under different filling heights, a typical cross-sectional model of Chagan Lake Station railway was established using the finite element numerical simulation software ANSYS. The temperature parameters of the roadbed were calculated based on the atmospheric temperature of local meteorological data, and the temperature fitting curve was used as the temperature boundary condition. Under different filling quantities, the temperature field of the roadbed was simulated for a freeze-thaw cycle, and the temperature curve changes were analyzed. The results indicate that as the filling height increases, the freezing depth line also increases accordingly. When the filling height is 2.5m, the maximum freezing depth at the roadbed is 1.7m. In a freeze-thaw cycle, the freezing process of soil develops from top to bottom, and the melting process develops in two directions: from top to bottom and from a certain depth of soil upwards, with the characteristics of "unidirectional freezing and bidirectional melting". The freezing period starts from early December of each year to the end of March of the following year, and completely melts until the end of April. Melting develops faster than freezing. Read More

Abstract: Permanent magnet synchronous motor (PMSM) has the advantages of high torque/inertia ratio, high power factor, fast dynamic response speed and high reliability, and has been widely used in various high-precision AC drive systems. Incremental encoders are usually used to achieve high precision position feedback information for permanent magnet synchronous motors. The use of sensors leads to cost increase, volume increase and reliability reduction. Therefore, the sensorless measurement technology of permanent magnet synchronous motor is more and more concerned and applied by industry and research fields. In this paper, the related literature of sensorless measurement technology of permanent magnet synchronous motor is investigated, and the sensorless measurement technology is comprehensively reviewed. This paper introduces in detail the basic principle of various sensorless measuring techniques, the accuracy of position measurement and the application in the type of permanent magnet synchronous motor. In this paper, the concept of speed pole logarithm ratio is proposed to divide the speed region, and the initial rotor position, low speed and medium speed non-inductive measurement methods are described and compared. Finally, the non-inductive measurement accuracy of permanent magnet synchronous motor is summarized. Read More

Abstract: To improve the mechanical properties and water resistance of gypsum specimens, thus solving the pollution problem due to the accumulation of flue gas desulfurization gypsum (FGD gypsum), etc. The article utilizes flue gas desulfurization gypsum, gypsum citrate, and mineral powder as the main raw materials under a fixed ratio. The Alkali-activation gypsum-based cementitious material (Alkali-activation GM-S95 system) was obtained by modifying it with 0-5% Na(OH) and Ca(OH)2 alkaline admixtures, and the mechanical properties and water resistance of the Alkali-activation GM-S95 system were thoroughly investigated. The structural characteristics of the Alkali-activation GM-S95 system specimens were investigated using XRD, TG, SEM and LF-NMR techniques to explore their interactions. The results showed that the compressive strength of the Alkali-activation GM-S95 system was significantly increased to 26 MPa when 4% Ca(OH)2 was added alone, and the water absorption was decreased to 12.5%.The addition of 4% Ca(OH)2 caused the crystals of gypsum dihydrate to be thicker and denser, and AFT and C-S-H gels were produced, which were attached around the crystals of gypsum dihydrate. The addition of different admixtures can reduce the proportion of large pores and further fill the crystal structure. In summary, the addition of 4% Ca(OH)2 can improve the compressive strength and water resistance of the samples of Alkali-activation GM-S95 system, thus laying a solid foundation for the comprehensive utilization of flue gas desulfurization gypsum. Read More

Abstract: This paper presents a design scheme of an adaptive laser cladding robot for the inner wall of variable diameter pipes. The robot is in the shape of a capsule, with an adaptive walking system, a mechanical support and balance system, a laser cladding system and a water cooling system, which can achieve efficient laser cladding and strengthening of the inner walls of different pipes. Among them, innovative designs such as pressure overload protection device and beam focusing lens adjustment motor have significantly improved the stability and accuracy of robot operation. Compared with traditional equipment, the robot is simple in structure, easy to disassemble, reliable in performance, high in automation, easy to maintain, and low in energy consumption. It provides an effective solution for laser cladding of pipe inner wall under complex and changeable working conditions, and helps to promote the wide promotion and application of laser cladding technology. Read More

Abstract: As a convenient handling tool, the pull rod car can use people's pushing and pulling to easily carry heavy objects, achieve the handling tasks that people need to complete, and reduce the burden on the shoulders and arms. The use of a trolley can reduce people's physical consumption, avoid overwork, especially suitable for long walks or need to carry a large number of items. Its biggest advantage is that it can complete different handling tasks through simple operations, so as to help people easily move items. The main design task of this paper is to transform the traditional draw-bar car, so that it has the function of telescopic stool and upstairs power. The design aims to solve the problem of carrying items and needing rest during shopping, providing a more convenient shopping experience. The specific design idea is to take the stool as the main body, and the shopping cart becomes its auxiliary function; The slider is used as a telescopic mechanism to realize the smooth expansion and contraction of the stool; Add the upstairs power function to drive the shopping cart upstairs through the motor and remote control. In terms of technical implementation, the base is welded with steel, the stool is made of high-strength polymer materials, and the telescopic mechanism is made of sliders. This paper mainly uses UG to carry out 3D modeling. Read More