bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on path planning of mobile robot based on improved Deep Q Network
Authors: Guan Meng , Yang Fu Xing , Jiao Ji Chao , Chen Xin Ping
Published: March 2021

In order to solve the problem of slow convergence and low learning efficiency when mobile robots use ordinary DQN algorithm to plan path in an unknown environment with insufficient prior knowledge, an improved DQN algorithm is proposed. A heuristic reward function is designed to realize continuous reward and solve the problem of slow convergence of DQN algorithm caused by reward sparsity. An adaptive exploration strategy is proposed to solve the problem of balance between exploration and utilization in reinforcement learning process, and improve the efficiency of exploration. Experiments show that the improved DQN algorithm not only has high learning efficiency and fast convergence, but also the planned path is optimal.
Research on trajectory planning of dual-arm cooperative robot
Authors: He Xiaoying , Zhang Yong , Gao Xingyu , Li Mingfeng
Published: March 2021

To meet the requirements of the market for complex and diverse operation tasks, the reasonable trajectory planning of the manipulator plays an important role in the completion of the task, which affects the motion accuracy and operation efficiency of the manipulator, the trajectory planning of the manipulator needs to meet the smooth change of motion parameters and no sudden change to ensure the smooth operation of the system. In this paper, the method of middle point interpolation is used to calculate and analyze the linear interpolation trajectory planning and arc interpolation trajectory planning of 7-DOF(degrees of freedom) redundant manipulator, and to realize the accurate trajectory planning of the end position of the dual-arm cooperative robot.
Research on Vehicle Driving Stability Based on Dynamics Co-simulation
Authors: Zhao Ya-Nan , Wang Zhong-Hui , Sun Ming-Ming , Liang Bing , Shao Liu-Bao , Tang Yan
Published: March 2021

Automobile braking system is an important guarantee for automobile driving safety, and improving automobile braking performance is an important task in automobile development. ESP system can effectively reduce the accident rate and improve driving safety. This paper systematically introduces the development of vehicle stability control technology from four aspects: dynamic modeling, state observation, control strategy and industrialization. It mainly introduces the state observation and control strategy.
Development of intelligent design platform for robotic drilling system based on CBR
Authors: Xu Ying , Zhang Yue , Xu Zhanghuan , Zeng Xianghu , Chen Jianqiang
Published: March 2021

In order to improve the design efficiency of the robotic drilling system, the case-based reasoning, CBR design technology is used in the development of the robotic drilling system design platform. The framework of the design platform of the robot hole-making system is constructed, and the key technologies for the construction of the intelligent design platform are studied, including the graphics similarity judgment method, parts coding rules, part parameterization rules, software and platform interface technology, drilling end effector geometric modeling, etc. Combined with the end effector design example, the effectiveness of this method is verified.
Research on the Design and Path Planning of Child-mother UAV System for Search Task
Authors: Cai Wenyanhong , Ye Zecong , Zeng Jun
Published: March 2021

UAVs are suitable for performing Dull, Dirty and Dangerous tasks due to their small size, strong flexibility and good concealment. The search task is one of the most typical tasks of drones. However, due to the limitation of technology and cost, the existing UAVs usually have one or more restrictions on flight time, flexibility and versatility. This creates certain restrictions for UAVs to perform different types of search tasks in different situations. In order to improve this situation, this paper proposes a search task-oriented unmanned aerial vehicle system, and designs the workflow to adapt to different types of search tasks. And according to the characteristics of the task, different types of path planning methods are designed for the mother UAV and sub-UAV respectively in order to improve the autonomy of the system. Finally, simulation experiments are carried out on MATLAB software to verify the effectiveness of these two methods, and the conclusion and the next work of the system are given.
Design of the AGV Trolley for Transporting the Drip Irrigation Belt Roll
Authors: Meng Fanzhao , Wei Daifeng
Published: March 2021

Automatic Guided Vehicle (AGV) is a kind of driverless transport vehicle which can carry, store, and load and unload goods. It can follow the preset path, complete the task, and has the functions of obstacle avoidance and safety protection, which is widely used in automatic production system. This paper introduces the design and development of AGV trolley to realize the automatic production transformation of drip irrigation belt production line for agricultural irrigation. According to the design requirements of the drip irrigation belt rolling AGV trolley for the transformation of the production line, based on the previous design experience and technology of the automatic guided trolley, from the actual needs of engineering application, combined with the path guidance technology, embedded control system, sensor detection technology, module control and system control management technology, a tape guided AGV trolley with lifting module is designed, which realizes the functions of rolling, transporting and storing of drip irrigation belt, and the production efficiency of drip irrigation belt is improved.
Research on the application of single point conductive adhesive in the electrical interconnection of display screen
Authors: Ming Zihao , Ma Xiao Song , Wu Keye , Tang Changhua
Published: March 2021

This paper studies the application of the single point conductive adhesive in the electrical interconnection of the display screen. The two ends of the electrical interconnection of the single point conductive adhesive are welding form and contact form respectively, and the volume is very small. The single point conductive adhesive can be soldered on the circuit board together with the circuit components, and the display screen can also be solderless flexible interconnection. However, because there is no suitable packaging form of display screen in the market at present, the display screen is modified in this study, and the display screen and circuit board are interconnected with single point conductive adhesive. The working effect of display screen and the power change of circuit board after interconnection with single point conductive adhesive are tested. The experimental results show that the display screen interconnected with single point conductive adhesive can work normally, the voltage of the interconnection point has a slight increase, and the input power of the circuit board has a slight increase. The experimental results show that the single point conductive adhesive can be used in the interconnection of display screen.
Workspace analysis and kinematics simulation of 6-DOF upper limb exoskeleton robot
Authors: Liu Hua Bin , Dai Zong Miao , Peng Xue Feng
Published: March 2021

In this paper, the outer non-humanoid robot 6-DOF upper limb bone as the research object, the establishment of a forward kinematics model of the robot be modeled, using the DH parameter method in Creo software to get the robot based on Monte Carlo Method Point cloud image of workspace. Based on ADAMS, the dynamic of the joint driving torque is solved, and the torque change curve of each joint during the vertical lifting of the arm is obtained. The simulation results show that the working space at the end of the six-degree-of-freedom upper-limb exoskeleton robot model can meet the working requirements, and the joint torque is relatively small, which lays the foundation for the subsequent trajectory planning and drive device design of the upper-limb exoskeleton robot.
Design and implementation of distance measurement system based on FMCW technology
Authors: Yunhe Su , Jing Xiao , Qingchun Huang , Meili Wei
Published: March 2021

In this paper, the distance information is obtained according to the relationship between distance and beat frequency in FMCW ranging principle, the ranging process of sawtooth wave as frequency modulation signal is described in detail, and the causes of ranging error are analyzed briefly. The distance measurement system of simulation uses Matlab software to write, and the hardware ranging platform is built by DB77M24A6426V2 millimeter wave radar module. It is verified that the distance measurement system design in this paper achieves more accurate ranging in the short distance measurement, and provides a relatively simple ranging waveform, which provides a relatively powerful reference basis for the subsequent ranging system design and hardware selection.
Design of a Feeding Device for Penaeus Vannamei Breeding Pond
Authors: Mao Wenwu , Wang Zijie , Yan Hao , Wang Dengkui
Published: March 2021

At present, the mechanization of shrimp culture in China is still low, and most of them are artificially fed. Artificial feeding is not only labor-intensive, but also has the disadvantages of uneven feed throwing. In this paper, a feeding device for Penaeus Vannamei breeding pond is designed, which mainly includes guide trolley, support body, feeding rod, storage plate and storage bucket, the feeding efficiency of Penaeus Vannamei is improved.
Structural design of spiral blade of concrete mixer truck
Authors: Zhao Lu-Yan , Li Peng , Liu Fu-Xiu
Published: March 2021

This article takes a concrete mixer truck actually produced by an enterprise as an example. According to the functions of the three-part spiral blades of the front cone, cylinder, and tail of the mixing drum, combined with theoretical knowledge, the Pro/E software is used to realize the re-realization of the blade spiral. design. A spiral line that is more in line with actual working conditions is derived, which provides a theoretical basis for the design and modeling of spiral blades of concrete mixer trucks.
Angle-resolved Micro-Raman, a prospectively automatic method of stress measurement for electronic packaging of semiconductor
Authors: Chang Ying , Xiao Aixia , Zhao Jiaxin , Ma Lulu , Meng Tian , Qiu Wei
Published: March 2021

Residual stress introduced during electronic packaging is one of the core factors affecting the efficiency, quality and reliability of advanced semiconductor devices. Therefore, it is important to reduce negative effect, even to increase positive influence through regulating the magnitude and distribution of residual stress on semiconductor devices, requiring a non-destructive, non-contact and automatic on-line method for the measurement of the surface and internal residual stress. This paper presented an angle-resolved Micro-Raman method for the measurement of the residual stress induced by electronic packaging of semiconductor.
Deviation Analysis of Pitot Static Probe Airflow Receiving for Civil Aircraft
Authors: Zhao Jiejue
Published: March 2021

The pitot static probe provides the atmospheric pitot pressure and static pressure information for the Air Data system for calculating flight parameters for flight. The installation angle of the f pitot static probe directly affects the accuracy of its airflow receiving, and directly affects the judgment of the aircraft and the crew. In this paper, we have conducted an in-depth analysis of the airflow receiving deviation of the pitot static probe, and simulated the large changes in flight parameters of a certain type of aircraft under different installation deviation angles. Finally, commonly used deviation treatment suggestions are given for the installation deviation of the full static pressure probe of a certain type of aircraft.
Modeling and simulation of surface topography in five-axis ball end milling
Authors: Wei Juan , Hou Xiaodong , Sun Chao
Published: March 2021

Computer simulation can be used to predict the machined surface topography and roughness, which can provide a basis for the reasonable selection of cutting parameters and tools. To do so, the motion trajectory equation of ball end milling cutter was established based on homogeneous coordinate transformation matrix. On this basis, a 3D surface topography simulation algorithm based on workpiece meshing is constructed. Finally, the influence laws of feed rate per tooth, path internal and initial phase angle on surface topography were analyzed by simulation. The conclusion has a good guiding significance for the surface quality control and adjustment of machining parameters in actual production.
In Situ Synthesized Graded TiC Particulate Reinforced Ni-based Composite Coating Prepared by Laser Cladding
Authors: Xu Lifeng , Xiao Rui , Qu Guang , Wang Dongsheng
Published: March 2021

Pure titanium (Ti) which had been processed by high energy ball milling, graphite and Ni60A self-melting alloy composite powder were used as the cladding materials. A test on the in situ synthesized graded TiC particulate reinforced Ni-based composite coating was carried out after presetting of the composite powder on the 42CrMo alloy structured steel base surface. Morphologies, tissue structures and microhardness values of samples were investigated by an optical microscope (OM), scanning electron microscope (SEM) and microhardness tester. Results show that in situ synthesis of TiC reinforced particulates is realized with pure Ti and graphite powder under laser cladding. TiC particulates which have a small density presents a graded distribution of less at lower and more at upper of the coating due to the floating effect in a melting pool. Therefore, in situ synthesized graded TiC particulate reinforced Ni-based composite coating was gained. Moreover, TiC particulates cluster and grow in the melting pool due to collision and bonding of TiC particulates in the floating process. Compared to TiC particulates at lower part of the coating, the TiC particulates at upper part of the coating possess a higher proportion of clusters and growth phenomena. The volume percentage of TiC particulates at middle and bottom of the composite coating is lower than 5%, while volume percentage of TiC particulates on the coating surface is no higher than 25%. Similar with distribution pattern of TiC particulates, microhardness of the composite coating is also high on surface and low deep layer of the coating.
Product Innovation Design Process Model Based on Knowledge Service
Authors: Zhang Kai , Guo Xin , Yu Miao , Chen Ling
Published: March 2021

With the advent of the era of knowledge economy, knowledge plays an increasingly important role in product innovation design. In order to help designers to acquire and apply knowledge in product innovation design process, a kind of model of product innovation design process based on knowledge service was proposed. Product innovation design was divided into several stages: requirement analysis, problem determination, problem solving and solution evaluating. And the mapping relationship between design process, service strategy and service knowledge was also analysed. Taking the designers as the main body of knowledge service, a knowledge service strategy supporting design process was proposed. In view of the different knowledge services required in different stages of product innovation design process, the forms and service strategies of knowledge in various stages of product design were studied step by step, and the product innovation design service composition model that conforms to the designer’s habits of mind was put forward. This method links the knowledge and design process in each stage of product innovation design process with the combination of innovation strategy and design knowledge, which is used to assist designers in tracking and applying the required knowledge resources for innovation design. Finally, a prototype system of product innovation design knowledge service was developed, and a design case of micro force measuring device was presented to demonstrate the practicability and validity of the proposed method.
High-Speed Wind Tunnel Twin-sting Adaptor Design and Verification for Commercial Aircraft
Authors: Liu Yang
Published: March 2021

Rear sting, Z sting, and fin sting supports are generally used to measure force and moment during high-speed wind tunnel tests for commercial aircraft, It is necessary to apply another support to obtain the sting interference. Twin sting support is the most appropriate way to get the sting interference due to less secondary interference, and the twin-sting adaptor is core part of twin-sting support, which directly affect the test data accuracy and test envelope. This work is to introduce design and verification of the twin-sting adaptor based on a commercial aircraft model, CAE was applied to analyze and evaluate the aerodynamics, strength and stiffness during the design of adaptor. The adaptor was finally verified in the high-speed wind tunnel testing, and testing data demonstrate that the design have less aerodynamics interference on the wing, and the accurate sting interference could be obtained. The design of twin-sting adaptor could offer a solution for commercial aircraft to carry out wind tunnel testing of sting interference and rear fuselage characteristics.
Damage Prevention Practices of Heating Loop Products for Space Remote Sensors
Authors: Yu Zhao
Published: March 2021

To provide effective protection of heating loop products for space remote sensors throughout the production test, causes of product damages and weak links were analysed, and some specific protection strategies were proposed. Firstly, a flexible protective coating which could be reused was designed. Secondly, the quality control department organized the production department and testing department of the product to formulate a full-link implementation scheme to assure continuous implementation of the proposed protection method in all links, including design, technique, inspection and test. This heating loop protection decreased the product damages significantly compared to those in the previous year. The total number of damaged heating loop products in one year decreased by 60% from 18 to 7. Damages of heating loop products during optical assembly, electric wiring, final assembly and transportation were controlled effectively. This study protects the manufacturing safety of heating loop products for spacecraft remote sensors.
Simulation study of T-shaped piezoelectric linear ultrasonic motor based on PZT piezoelectric ceramics
Authors: Li Shuiping , Li Ran
Published: March 2021

In this paper, the T-shaped structure of linear ultrasonic motor was studied by means of establishing a THREE-DIMENSIONAL model of mechanical structure through SolidWorks and completing relevant simulation analysis through ANSYS Workbench. The finite element simulation analysis consists of four part: i. modal analysis, it determines the working mode and ensures that the frequency difference between the two working modes is as small as possible; ii. Harmonic response analysis furtherly verifies that the resonant response occurs at the operating mode frequency; iii. transient dynamic analysis demonstrates that the motion trajectory of the motor stator driving foot meets the theoretical requirements of ellipse shape. iv. drive signal and prototype are tested to verify the simulation analysis.
Analysis and treatment of cracks in LPG spherical tank
Authors: Jiang Chengjun , Du Yannan , Zhang Xiaoli , Pan Weiguo
Published: March 2021

During the first periodic inspection of the LPG spherical tank, a crack was inspected when the inner shell was detected by fluorescent magnetic powder test. The cause of the crack was analyzed by macromorphology examination, chemical composition analysis, hardness test and metallographic examination. Analysis results show that unreasonable welding procedure, no preheating process, improper storage of weld rods result in martensite structure of the welded joint, welding residual stress and diffusible hydrogen, which is the typical characteristic of the welding cold crack. The repair measures are taken to solve the problem and reduce the hidden dangers.
Simulation Investigation of a Soft Hydraulic Artificial Muscle
Authors: Liu Jianbin , Zuo Siyang , Wang Litong , Zhang Yongqin
Published: March 2021

This paper presents a soft hydraulic artificial muscle (SHAM) design, which replaces the cylinder, rod and piston in traditional hydraulic cylinder with soft structures. The presented muscle has the advantages of high output force level and good adaptability to environment. Modelling and simulation are conducted after introducing the working principle of the SHAM. Simulation results show that the output force can be as large as 160N with 0.8MPa input pressure. The effect of mixed air into the working fluid has also been investigated and discussed. Above advantages make the SHAM perfect for applications such as exoskeletons.
Design of multilayer Marine transportation tooling for large wind turbine blades
Authors: Hu Jing , Liao Guomin , Hu Guichuan , Ren Jing
Published: March 2021

Aiming at the long-distance cross-sea transport of offshore wind turbines blades, and proposing a solution of multilayer marine transportation through the analysis of the characteristics and requirements of marine transport of blades. Designing a multilayer marine transportation tooling for the large wind power blade GW90 which is 90 meters long and weighs 32 tons. Designing the main structure to solve the problem of complicated and large load on blades, designing the connecting structure to solve the problem of stable connection between each multilayer tooling, designing the position structure to solve the problem of installation and positioning of blades and tooling, and using the finite element analysis method to verify the design. Finally, a multilayer offshore transportation tool with safe structure, clear function and feasible design is proposed, which provides new exploration and ideas for the efficient and safe transportation of offshore wind power blades.
Laser wireless energy supply system of high-potential monitoring equipment based on machine vision
Authors: Yu Huiling , Chen Zhongwei
Published: March 2021

Real-time monitoring of high-voltage power equipment is an important link to ensure the safe and stable operation of the power system. The independent power supply of the monitoring equipment can ensure that the monitoring data is stable and effective without being affected by the power grid. This paper designs and builds a laser wireless power supply system based on machine vision and tracking and targeting technology for the actual application needs of high-potential monitoring equipment in power grids. The article introduces the overall architecture of the laser wireless power supply system and elaborates on the control method and image processing strategy of the tracking and targeting unit. The article proves the feasibility of the scheme through experiments, and realizes the accurate matching of the position of the photovoltaic cell in the presence of background interference. The research results of this article can provide technical support for the energy supply of high-potential monitoring equipment of the power grid.
Competitive Adaptive Reweighted Sampling Method for Fault Detection
Authors: Xuan Wang , Wang Yanxue
Published: March 2021

According to Darwin’s theory of evolution, a variable combination with the strongest correlation between selection process variables and quality indicators is developed. This is called competitive adaptive reweighted sampling (CARS). In this article, the absolute value of the partial least squares regression coefficient is used to assess the importance of each variable. Next, we select variables based on the regression coefficients of variables and quality indicators, including forced variable selection based on exponential decreasing function (EDF) and competitive variable selection based on adaptive reweighted sampling (ARS). Finally, we use cross-validation (CV) to select the subset with the lowest root mean square error of CV (RMSECV). The Tennessee-Eastman (TE) process is used to evaluate the performance of the proposed fault detection method. The results show that CARS can find the best combination of certain key variables, improving the fault detection capability of quality indicators.
Intelligent Siagnosis Algorithm for Bearing Faults Based on Vibration Potential Features and Affinity Propagation Clustering
Authors: Li Meng , Wang Yanxue
Published: March 2021

In order to achieve intelligent classification of bearing faults, after comparing a large number of mechanical fault signal features, this paper proposes a bearing intelligent diagnosis algorithm based on vibration potential energy feature extraction and AP clustering. The potential energy features are extracted from the multidimensional eigenmode function (IMF) of the vibration signal after the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN), and after self-weighted feature selection, the Affinity Propagation Clustering (AP) algorithm is used to achieve accurate classification of unlabeled faulty bearings. After data validation, the method can be better applied to the fault classification of rolling bearings, and the performance is better than the traditional classification and diagnosis algorithm. The algorithm is used to guide intelligent fault diagnosis of unlabeled data and to improve the applicability of AP clustering algorithm in rotating machinery fault diagnosis.
Bending-fatigue performance of the dissimilar joints of Fe-Mn-Si memory alloy and 304 stainless steel
Authors: Liu Linlin , Zhao Tianxiang , Zhou Chao Yu
Published: March 2021

The dissimilar joints of Fe-17Mn-5Si-10Cr-5Ni memory alloy and 304 stainless steel were welded by 5 kw transverse flow CO2 laser. The fracture morphology, microhardness of the welding joint was analyzed by field emission scanning electron microscopy, micro hardness tester, and bending fatigue test. The results showed that the fracture location of dissimilar joint is in the welding joint, and the fusion zone to weld areas prone to stress concentration while the formation of cracks. The full cyclic fatigue fracture of dissimilar joints consisted of the extension zone and instantaneous fracture zone. In the former, there were fatigue striations, dissociation steps and some arc tearing ridges, showing typical quasi-cleavage brittle fracture characteristics, and in the latter, there were a lot of dimples, showing plastic fracture characteristics. The toughness of dissimilar joint is better than that of the 304 stainless steel joint.
Operation Performance Test of Aerospace Mechanical Pumps and Verification of Their Environmental Adaptation
Authors: Zhang Huandong , Yang Tao , Zhao Zhenming , Meng Qingliang , Zhang Ping
Published: March 2021

In this paper, one aerospace centrifugal pump with flowrates of 1~2g/s was developed which was applicable to the mechanically pumed two phase loop (MPTL) system. Moreover, an experimental test platform was built to test and verify the performances of pump. Besides, the environmental adaptation tests of the designed pump were verified. Results show that: 1) the flow rate and lift of the pump at the rated working point are 2.043g/s and 0.0517MPa, while the input power is only 9.92W. These can meet requirements of the design indexes. 2) The input power is only 4.71W under the two-phase operation state and this pump can transfer the heat of 240W, and the pump shows a very high energy efficiency ratio (EER). 3) The lift of designed pump is constant at specified rotation speed and it can assure the temperature stability of MPTL system. 4) This pump can meet the requirements of services in vibration, vacuum and thermal cycling environments.
Non-destructive Testing Assisted by Six-Axis Manipulator Based on POE Formula
Authors: Hou Xiaoling , Gao Xingyu , Bin Liao , Peng Yanhua , Mao Yikai
Published: March 2021

At present, aluminum plates are widely used in aerospace, machinery, and other fields because of their light weight, good manufacturability, and strong corrosion resistance. However, during long-term use, defects that will affect the structural strength such as cracks are easy to appear. Therefore, it is necessary to conduct automatic non-destructive testing of large metal plates to determine the location, size, and structural damage to their defects. Compared with manual detection, automated detection has many advantages such as high detection efficiency, high repeatability, strong flexibility, and low labor intensity. Based on the spinor theory, this paper uses the product of exponentials (POE) to model the kinematics of the Aubo-i5 manipulator and obtain the positive kinematics equations, which are compiled by analytic geometry and algebraic methods combined with Paden-Kahan subproblems and matrix theory. The inverse kinematics algorithm of the 6R manipulator is based on this model. An automated non-destructive testing system including a robotic arm and ultrasonic phased array testing equipment was built. At the same time, a robotic arm simulation platform was built based on ROS, and the inverse kinematics algorithm was used to control the robotic arm through the MoveIt!. The angle error can be controlled within 2.5°.
Analysis of the Axial Fan Performance Mounted on a 4.5kW Aviation Motor
Authors: Liu Bin , Yu Zhongjun , Fu Jia , Chen Zutao
Published: March 2021

Integrating an axial flow fan with the rotor is a sufficient cooling method for high-speed and high power density motors. Different from the axial fan design work under ideal intake condition, i.e. the intake flow of the fan is axial and uniform, the flow in actual engineering is more complex, which means the flow characteristics of an integrated fan are changed and disturbed. It leads to a performance penalty of the fan, and in some conditions it makes the fan stall, so it is important to get a knowledge of the flow characteristics and the performance of the integrated fan. A certain 4.5kW aviation motor with integrated axial fan is taken as the research object. Firstly, the motor-fan coupling simulation model and ideal axial intake simulation model are established, in which the mass flow rates are same, then calculation is conducted. Secondly, the simulation results are analyzed and compared, focusing on the performance of the axial fan, especially the static pressure rise, and the conclusion is obtained that the static pressure rise in ideal axial intake situation is higher than that in coupling situation. Furthermore, the reasons for the characteristics change are explored, finding that the increase of flow turbulence due to the more complex wind road structure is the main cause for these changes. This paper investigates the flow characteristics and axial fan performance mounted a whole motor, making a contribution to better understand the changes in fan performance under motor-fan coupling situation.
Effect of Cr on microstructures and properties of AlTiVZr0.2Crx light weight high entropy alloys
Authors: Wang Yongqi , Li Anmin , Wei Shanjun , Wu Yu , Wang Chang
Published: March 2021

AlTiVZr0.2Crx (x=0,0.4,1) high entropy alloys have been prepared by powder metallurgy technology, and the effects of Cr content on the microstructures and properties of the alloys have been studied. The results show that the AlTiVZr0.2Crx alloys are mainly composed of body-centered cubic solid solution (BCC), face-centered cubic solid solution (FCC), and Al2Zr, AlTi2 and Cr2Ti intermetallic compounds. The addition of Cr promotes the transformation of the alloys from FCC structure to BCC structure and generate new phase Cr2Ti. The microstructure of the alloys are mainly massive or granulate. The hardness, compressive strength and elastic modulus of AlTiVZr0.2Crx alloys increase with the increase of atomic ratio of Cr content, the maximum hardness of AlTiVZr0.2Cr alloy is 685.3 HV, and the maximum compressive strength and elastic modulus are 1180.36 MPa and 30221.36 MPa respectively. The addition of Cr content also affects the friction coefficient and wear resistance of the alloys. With the addition of Cr, the friction coefficient and wear resistance increase first and then decrease. The wear resistance of the AlTiVZr0.2Cr0.4 alloy is the best in this experiment.
Investigation on Terminal Correction in Theoretical Model of the Microperforated Panel Absorber
Authors: Yang Xiaocui , Zhu Nannan , Zhao Rongxing
Published: March 2021

Microperforated panel (MPP) absorber is promising sound absorbing structure for the noise reduction. It is extremely especially to construct accurate theoretical sound absorbing model of the MPP structure for design and development of an excellent sound absorber. Thus, modification and validation of the terminal correction in theoretical sound absorption model of the MPP absorber is investigated in this research, which aimed to improve its accuracy and reasonability. Firstly, based on the Maa’s theory, classic sound absorption model of the MPP absorber was presented and treated as basic reference of the whole research. Secondly, through a set of verification experiments, necessity and importance of the research on reasonability of terminal correction was revealed. For the superposition of several monolayer MPP absorbers, when its sound absorption coefficient was derived as the multilayer MPP absorber through the transfer matrix method, the terminal corrections for the former n-1 monolayer MPPs should be removed, because length of these MPPs was 0. Thus, it was essential to take length of the rear cavity into account for the terminal corrections in the theoretical sound absorption model of the MPP absorber.
Study on Influencing Factors and Laws of Temperature Field Distribution of Infrared Hot Air Reflow Soldering
Authors: Ji Chenyang , Pang Zhanming , Zheng Yi , Zhou Hongda , Chen Cai , Yin Yu Tian , Gong Yubing
Published: March 2021

The quality of solder joints formed by reflow soldering is closely related to the temperature profile of solder joint during the hot air reflow soldering process. The temperature profile of solder joint is directly determined by the process parameters of the reflow furnace as the layout of the PCB design remains same. In this paper, the temperature model of the printed board assembly during reflow soldering is numerically built and simulated to obtain the temperature distribution. Furtherly, several process parameters, such as the temperature of each temperature zone, convective heat transfer coefficient and conveyor belt speed of reflow soldering furnace, are selected as the input variables, and the heating factor, time of super liquidus and peak temperature are aimed as the output parameters. The Latin hypercube sampling design is applied to construct the response surface of the output parameters. The influence of these process parameters during the reflow soldering on the temperature profile of PCBA is studied comprehensively. The main influencing process parameters of the reflow soldering are identified and their influence laws are obtained. The research results provide valuable reference and basis for reflow soldering process design.
Study on the Influence of Surface Texture on the Dynamic Performance of Sliding Bearing
Authors: Chen Changsheng , Li Shan , Ma Zhenlai , Li Guoping , Wang Qiang
Published: March 2021

Rotor bearing system is an important part of mechanical equipment. The vibration of equipment caused by rotor system has become a more important problem in engineering. In this paper, the texture technology of the inner surface of the bearing is studied to explore the influence of the surface texture on the vibration reduction characteristics of the bearing. The results show that reasonable texture parameters and texture distribution can reduce the friction of the bearing and increase the end discharge. There is an optimal texture density and texture region. In this paper, a bearing test platform is set up to test and study the tiles with different surface texture. The test results show that the amplitude of the axis orbit of the sliding bearing with texture is significantly reduced, the principal stiffness and cross stiffness of the textured bearing are larger than those without texture, the damping is slightly larger under high speed and light load than that without texture, and the texture has obvious damping effect on the bearing shell.
Fault diagnosis of rotating mechanical bearing based on adaptive noise-complete ensemble empirical modal decomposition and time-reallocated multisynchronous compression transform
Authors: Dai Hanfang , Wang Yanxue
Published: March 2021

Due to the noise interference in the original vibration signals measured from vibration sensors, it is necessary to noise reduce the signals before extracting fault features from them. This paper proposes a fault feature extraction method combining the adaptive noise-complete ensemble empirical modal decomposition (CEEMDAN) and the time-reallocated multisynchronous compression transform (TMSST), which first decomposes the original signal, then combines the relevant index values of the decomposed signal to filter the optimal signal components, and finally uses the TMSST to extract the fault features from the reconstructed signal. In this paper, a set of simulated signal data and two sets of experimental data are used to evaluate the performance of the method, and the results show that the method works well for rolling bearing fault signal identification.
Research on comprehensive evaluation of data link based on G1 method and entropy weight method
Authors: Jin Ming , Zhang Junyan , Cui Shuo , Kang Mei , Xiao Yi , Xiang Rongxin , Yan Zhenye
Published: March 2021

With the rapid development of mobile Internet technology and the advent of the 21st century Internet and information age, data has become the most important strategic core resources. With the rapid development of ubiquitous power Internet of things construction, there are still many problems in the data link monitoring and data management: the low effectiveness of data transmission affects the normal operation of the data link; there are few data evaluation models, which lead to the problem of one sidedness and subjectivity in the understanding of the operation status of the data link. Aiming at the problem that the current data link cannot directly show the link quality, this position proposes a comprehensive evaluation method for the entire data link based on the order relationship analysis(G1) method and the entropy weight method. First, establish a complete data link indicator system, and then separately Use the order relationship analysis method to determine the subjective weight, use the entropy weight method to determine the objective weight, and finally combine the two to determine the comprehensive weight, and obtain a comprehensive score that reflects both the expert level and experience and the actual situation related data. The data and transmission conditions of each link are shown, and the comprehensiveness, rationality and scientificity of the method are also demonstrated.
Prediction of simulation parameters of fiber laser cleaning Range hood based on BP neural network
Authors: Yu Jinghua , Chen Yifeng
Published: March 2021

In order to study the influence of process parameters on the surface oil pollution of fiber laser cleaning Range hood, the test of laser cleaning to remove the surface oil pollution of Range hood was carried out. Based on the BP neural network, a prediction model of the process parameters such as laser scanning speed, cleaning times and cleaning line spacing is established. the training samples collected by the cleaning test were trained online, and the training model was verified by using the test samples. The results show that the neural network prediction model has high accuracy and good training effect, and the maximum relative error between the predicted value and the test sample value is 8.4%. The model can predict laser cleaning effectively oil stain quality on Range hood surface.
Research on condition monitoring device of HDTSE for intelligent maintenance
Authors: Lin Chuanglu , Wei Zhang , Mo Shaomeng
Published: March 2021

The role of HDTSE is becoming increasingly important. According to the operation characteristics of, This paper analyze the causes of escalator failure, adopts Internet of things, intelligent sensing and distributed technology, presents an escalator operation monitoring system architecture for intelligent maintenance, design the hardware and software of the monitoring device, realize the real-time monitoring of key parameters of escalator and fault warning. It has high application value.
The finite element analysis of concrete pipe pile vacuum sucker
Authors: Wang Wei , Xu Ji Yong , Wang Yan , Qin Yuan Lei
Published: March 2021

The adhesion degree between the vacuum sucker and the surface of the adsorbed object seriously affects its adsorption performance. In order to solve the problem that the curved surface of cylindrical concrete pipe pile is not easy to be adsorbed, an elliptical vacuum sucker is designed. In order to study the influence of different unadsorbed areas on the adsorption force, the flow field inside the vacuum sucker is simulated and analysed by using computational fluid dynamics software (fluent). The corresponding curve between the unadsorbed area of the sucker and its adsorption force is obtained. According to the relationship, through the analysis of the size of the unconnected area of the vacuum sucker, it can be known whether the adsorption capacity of vacuum sucker meet the working requirements of the vacuum sucker adsorption cylindrical concrete pipe pile.
Modeling and optimization of B-axis hydraulic delay for gantry-type CNC machine tool
Authors: Fei Ya , Chen Xuezhen , Li Ying , Liao Gang , Zhang Weiwei , Zhang Yun
Published: March 2021

Due to the limitation of dimension, structure and material, aviation structural workpiece is usually processed by AB rotary axis five-axis CNC gantry-type machine tools with large torque. However, the B-axis mechanical structure of gantry-type machine tools is complex and bulky, and hydraulic system is adopted for gravity balance. After the long production period of the machine tool, the hydraulic balance force of the B-axis is lost immediately and the spindle goes out of control when it emergency stops, which seriously endangers the quality of workpiece. In view of this phenomenon, this paper takes the hydraulic control system of machine tool as the breakthrough point, and analyzes the hydraulic system without adjusting the mechanical structure. And the mathematical model of hydraulic system is established. The hydraulic control system of B-axis is optimized by the simulation of MATLAB/Simulink. On the premise of improving the stability of the system, the duration of hydraulic balance force is extended, and the deflection time of 2 seconds is delayed, which effectively reduces the processing risk of workpiece.
Quality Inspection of Gluing in Narrow Border Based on Depth Map
Authors: Zou Xiang , Gao Xing-Yu , Liao Bin , Wei Chuan-Nen
Published: March 2021

To solve the problem of glue breakage and overflow in the packaging process of mobile phones, a glue detection algorithm based on the depth map is proposed. By collecting the image no gluing and gluing after dispensing, the pixel value of each frame in the corresponding position of the corresponding sample is sequentially intercepted in the same sample, and the glue contour is reconstructed by rearranging the intercepted ROI. Last, measure the width and height information of the glue according to the contour, and judge the defect problem at the same time. Experimental results show that the algorithm can accurately measure the result of the micron-level glue, and accurately determine the lack of glue. At the same time, the measurement accuracy of the algorithm is 0.01mm, and the measurement results are accurate and stable.
The Measurement and Control Research of Non-metal Material Volatile Organic Compound in Civil Aircraft
Authors: Ru Wang
Published: March 2021

The paper expounds the source of volatile compounds in the air of civil cabin. By measuring the air quality in civil cabin and Volatile organic compound (VOC) content of typical non-metal material, in addition, comparing domestic control laws and standards of VOC in civil airplane cabin air with which in overseas, the paper attend to offer recommendations to control civil airport non-metal material VOC and provide a reference for control of non-metal material in civil airplane cabin to related enterprises. The research is aimed to create a foundation to produce a new representation of green and safe domestical civil airplanes. It is very meaningful to motivate domestical civil airplane industry and the international progress of enormous industrial chain that influences.
The microstructure and properties of Cr/Ni alloying layer after surface alloying treatment induced by continuous scanning electron beam process
Authors: Ren Xulong , Wang Rong , Wei Deqiang
Published: March 2021

The surface alloying of scanning electron beam can improve the microstructure and mechanical properties of steel materials. In this paper, Cr/Ni alloying treatment was performed on 35CrMo alloy structure steel by using continuous scanning electron beam to improve surface performance. The influence of scanning electron beam technology on the structure of alloy layer is studied, and the influence of coating thickness on the structure and properties of the alloying layer is discussed. The results show that the surface of 35CrMo steel is composed of alloying layer, heat affected zone and matrix. The microstructure of the alloying layer is short columnar crystal, equiaxed crystal and acicular martensite. The surface hardness can reach 770HVwhen the coating thickness is 5μm, which is 2 times of the matrix. With the increase of Cr/Ni coating thickness, the surface of sample hardness decreases, and the corrosion resistance of the sample increases.
Study on the reverse martensitic transformation of Fe-Mn-Si alloy based on constraint state
Authors: Liu Linlin , Zhao Yijian , Zhao Tianxiang
Published: March 2021

The constrained stress-induced ε reverse martensitic transformation characteristic of Fe-Mn-Si alloy was studied by X-Ray Diffraction (XRD) and metallographic analysis. The results show that the origination temperature (As) of the constrained reverse transformation of Fe-Mn-Si alloy in cement matrix, compared with the unconstrained alloy, was immovability, the pause temperature (Af) was elevated, and the ε reverse martensitic transformation became slower under the same recovery temperature. At the same time, the amount of the constrained stress-induced ε reverse martensitic transformation decreased and the reverse transformation temperature zone broadened with the increasing degree of prestrain.
Research on adaptive thermal control system of space optical remote sensor
Authors: Yu Feng , Meng Qing Liang , Xu Na Na , Yu Zhi Qiang , Zhang Ping
Published: March 2021

The traditional thermal control system of the space optical remote sensor is mainly based on passive thermal control and supplemented by active thermal control of electric heater. But with the development of the remote sensor in the direction of multi-task and multi-function, the thermal control system needs to meet the requirements of low thermal control resource consumption under the condition of multi heat source and large heat load, and high adaptability under the condition of multi attitude complex orbit. The traditional thermal control system can not satisfy these new requirements. In this paper, a new adaptive thermal control system is studied. A geostationary orbit camera as an example is taken to compare the design scheme of the traditional thermal control system and the new thermal control system. The simulation results show that the new thermal control has the advantages of more optimized system resources and stronger temperature adaptability under complex tasks, which provides a new idea for the subsequent thermal control design of complex large space optical remote sensor.