The manufacturing and assembly efficiency of product is related to the product module division scheme. In order to further improve the manufacturing and assembly efficiency of complex product, a new product module division and architecture evaluation method was proposed. Firstly, using the existing module division scheme of complex product, the correlation matrix between parts in each module of the product was established, the correlation matrix (sub-matrix) was combined, and the correlation value between modules was added to obtain the correlation matrix between parts of the whole product; secondly, based on the information entropy theory, the concepts of cost equilibrium and complexity equilibrium were proposed. Combined with the modularity and minimum description length, the weight of each evaluation index was calculated by the entropy weight method, the comprehensive evaluation index was obtained, and different module division schemes were evaluated; finally, the rationality and feasibility of the proposed method were verified by taking the module division of shield screw conveyor as an example. Through the existing module division scheme of shield screw conveyor, the correlation matrix between its parts was established. Different module division schemes were obtained by hierarchical clustering, and their comprehensive evaluation indexes were compared, from which an optimal module division scheme was selected to express the product architecture composition of shield screw conveyor. The product architecture evaluation method based on modularity and equilibrium can effectively and reasonably evaluate the architecture of complex product, and provide a theoretical basis for improving the manufacturing and assembly efficiency of complex product.

In order to make full use of the implicit semantic relationship between ontology concepts to support the product function innovation design process, an ontology semantic mining and functional semantic retrieval method based on the network representation learning was proposed. Firstly, based on the determinate semantic relationships in the ontology, the network representation learning was used to mine the implicit semantic relationships; then, based on the vector operation of semantic analogy, the potential functional semantic relationship between ontology concepts was established, and the functional semantic vector was expressed; finally, through the similarity calculation of the functional semantic vector, the expansion from functional requirements of users to cross-domain functional design data was realized, and the corresponding design data retrieval method and its process were established. The product design example shows that the proposed ontology semantic mining and functional semantic retrieval method is conducive to obtain cross-domain design knowledge from the perspective of product function, which can provide more inspiration for designers.

Permanent magnet synchronous motor (PMSM) is widely used in different fields because of its simple structure, stable operation, high efficiency and various shapes. During the use of the PMSM, various faults will inevitably occur, such as the demagnetization fault, the circuit fault, the rotor eccentricity fault, the bearing fault and so on. Based on the structure and working principle of the PMSM, the causes and diagnosis methods of various faults were summarized, and the advantages of model construction and signal processing in fault diagnosis were analyzed. The research results provide a certain theoretical basis for the fault diagnosis of PMSMs.

The traditional spiral drum type cobalt crust mining head will mix a lot of waste rocks in the actual mining process. In order to realize the accurate stripping of cobalt crusts in complex and changeable seabed mining areas and improve mining rate, it is necessary to design a mining head that can be mined efficiently. Firstly, aiming at the geomorphic characteristics of the seabed cobalt crust distribution, the basic requirements for mining head design were put forward, and a suspended mining head was designed and its parametric design mathematical model was established. Then, based on the designed suspended mining head, with the goal of reducing the specific energy consumption in the crushing process of cobalt crust, taking the non-interference of mining head pick, reasonable layout of intercept distance, cobalt crust production capacity compliance and maximum power limit as constraints, an optimization model of structural parameters and working parameters of the suspended mining head was established and solved by the genetic algorithm. Lastly, in order to verify the rationality of the optimization model, the ABAQUS software was used to simulate the crushing process of cobalt crusts by the suspended mining head, and the specific energy consumption of crushing cobalt crusts by the mining head before and after optimization was obtained, and the stability of the mining head was compared and evaluated based on the load fluctuation characteristics. The theoretical calculation results showed that the specific energy consumption of crushing cobalt crust by the suspended mining head after optimization was about 44% lower than that before optimization. The simulation results showed that the specific energy consumption and the load fluctuation coefficient of crushing cobalt crust by the suspended mining head after optimization were reduced by 18% and 31.3% than those before optimization, which verified that the effectiveness of the optimization model. The designed suspended mining head can not only significantly improve the energy consumption and load fluctuation, but also can better adapt to the distribution characteristics of seabed cobalt crusts, which can provide an important basis for the commercial mining of deep-sea cobalt crusts.

Aiming at the problem of low obstacle crossing height of sweeping robot, a trigger hydraulic auxiliary obstacle crossing mechanism was designed. The mechanism can switch back and forth between normal driving and obstacle crossing modes without additional driving, which reduces the complexity of the control unit. Firstly, the structure and working principle of each module of the mechanism were introduced；secondly, the three-dimensional structure diagram of the auxiliary obstacle crossing mechanism was drawn，the force on the obstacle crossing critical point of driving wheel was analyzed, and the calculation formula of auxiliary driving force was given; thirdly, the statics analysis of its vulnerable part—hydraulic rod was carried out, and the obstacle crossing simulation of the sweeping robot equipped with trigger hydraulic auxiliary obstacle crossing mechanism was carried out to verify the feasibility of the mechanism in theory; finally, according to the parameters of the sweeping robot, combined with the actual working conditions, the auxiliary obstacle crossing mechanism was made and carried on the sweeping robot for experiments. The theoretical analysis and experimental results showed that the trigger hydraulic auxiliary obstacle crossing mechanism could provide sufficient auxiliary driving force, raise the obstacle crossing height of the sweeping robot, and effectively solve the problem that the sweeping robot was stuck due to insufficient power. The research result can provide reference for the structural optimization design of sweeping robot.

Aiming at the problem that the key components of the roadheader under the coal mine are easily damaged and its cutting performance is poor during cutting, but it is difficult to carry out related research in the laboratory, taking the EBZ160 roadheader as the prototype, an experimental prototype was manufactured based on the similarity theory, and an active vibration cutting method was proposed. Firstly, based on the working principle and dynamics theory of the roadheader experimental prototype, the modal simulation analysis for the experimental prototype was carried out by using the ANSYS Workbench software, and the modal test was carried out based on the hammer method. The first six natural frequencies and modal shapes of the experimental prototype under the no-load state were obtained. Then, taking the cutting specific energy consumption as the evaluation index, the cutting performance of the roadheader experimental prototype under the cutting mode with or without active excitation was studied. The results showed that the maximum relative error between the simulated value and the test value of the first six natural frequencies of the roadheader experimental prototype was 9.92%, which verified the accuracy of the modal simulation analysis results and could provide a basis for the selection of subsequent excitation frequency; the cutting specific energy consumption of the roadheader experimental prototype without and with active excitation was 0.077 6 kW·h/m³ and 0.051 2 kW·h/m³, respectively, which indicated that the performance of the proposed active excitation cutting method was relatively good. The research results provide a new direction for the expansion of roadheader cutting methods, and provide an experimental basis for the structure optimization and cutting efficiency improvement of the roadheader.

The arrangement, size and shape of the textures on the textured sliding friction pair surface are the key factors that determine the pressure distribution and bearing force. In order to improve the lubrication and bearing characteristics of the textured sliding friction pair surface, a kind of variable texture (texture with various sizes) structure was proposed. Taking the spherical crown texture as the research object, the CFD (computational fluid dynamics) simulation models of the single-size texture with different arrangements and the variable texture with square-arrangement were established, and the pressure distribution and bearing force of the single-size texture with different arrangements were analyzed; on this basis, the pressure distribution and bearing force of four types of variable textures with square-arrangement, such as small radius at both ends, large in the middle (A-type), large radius at both ends, small in the middle (B-type), shallow depth at both ends, deep in the middle (C-type), and deep depth at both ends, shallow in the middle (D-type), were studied. The results showed that the single-size texture with square-arrangement had the strongest lubrication effect and the largest bearing force; with the increase of dislocation angle, the synergistic lubrication effect between textures weakened and the bearing force of the texture decreased; the pressure distribution curve of the single-size texture was a periodic fluctuation curve, which was composed of pressure distribution curves of multiple single texture. The trend line of pressure distribution curve of the variable texture with square-arrangement was approximately fluctuating in a sine or cosine law due to the synergistic lubrication effect of the front and rear textures; among the four types of variable textures with square-arrangement, the bearing force of the B-type variable texture was lager than that of A-type, and D-type was larger than C-type, that was, the larger the radius, the deeper the depth of texture at both ends, or the larger the proportion of such texture, the bearing force of the variable texture was larger. It can be seen that the variable texture is more helpful to improve the lubrication and bearing performance of the friction pair surface than the single-size texture.

Aiming at the problem that it is difficult to determine the liner thickness and fiber stress ratio according to the designed cylinder burst pressure and fatigue life in the design stage of composite hydrogen storage tank with aluminum liner (also known as ‘type III hydrogen storage tank’), the relationship between burst pressure and fatigue life of type III hydrogen storage tank was studied. Firstly, the finite element calculation model of type III hydrogen storage tank was constructed, the prediction method of cylinder burst pressure and fatigue life based on finite element was proposed, and the stress distribution of type III hydrogen storage tank under the influence of liner thickness and fiber stress ratio was analyzed. Secondly, the effect rule of liner thickness and fiber stress ratio on burst pressure and fatigue life of type III hydrogen storage tank was studied. The results showed that: in a certain range of liner thickness and fiber stress ratio, when the liner thickness increased, the increment of cylinder burst pressure increased lesser; when the fiber stress ratio increased, the cylinder burst pressure increased greatly; the logarithmic fatigue life of type III hydrogen storage tank was basically linear with liner thickness and fiber stress ratio. Finally, based on the burst pressure calculation formula of filament-wound pressure vessel and the logarithmic fatigue life fitting relationship formula of type III hydrogen storage tank, the relationship between burst pressure and fatigue life of type III hydrogen storage tank under different conditions was obtained. The research results can provide reference for the optimal design of type III hydrogen storage tank structure.

With the continuous increase of drilling depth in Sichuan and Chongqing, the pipe string is vulnerable to the influence of cuttings in the well during running, resulting in stuck drilling, and even major accidents such as drilling tool fracture. In order to improve the cuttings transport capacity in shale gas horizontal wells in Sichuan and Chongqing, two new types of drill pipes, the suspended aluminum alloy drill pipe and the new pulse jet drill pipe, were designed and compared with the ordinary drill pipe. Firstly, the structure and cuttings carrying principle of three kinds of drill pipes were analyzed theoretically. Then, the cuttings carrying simulation models of three kinds of drill pipes were established in the ANSYS software, and different grid division methods were used to verify the grid independence and convergence of each simulation model, and the accuracy of the simulation model was verified by using the indoor cuttings transport device. Finally, the cuttings carrying capacity of three kinds of drill pipes was simulated and analyzed under the change of cuttings particle size, drilling fluid inlet displacement and well inclination angle. The results showed that the cuttings carrying capacity of the suspended aluminum alloy drill pipe and the new pulse jet drill pipe was higher than that of the ordinary drill pipe. The research results are of great significance to improve the transport velocity of cuttings in the horizontal wells, improve the cleanliness of wellbore and reduce the formation of cuttings bed.

The contact is the core component of the electrical connector, and the wear caused by plugging will lead to its electrical contact performance degradation or even failure. In view of above problems, a plug-in wear detection method for the electrical connector was proposed. Based on the designed detection device, the plug-in test for the electrical connector was carried out, and the contacts of the electrical connector were detected by timed infrared thermal imaging during the test process; at the same time, the distribution characteristics and changing law of wear debris between electrical connector contacts during plugging process were analyzed, and the infrared thermal imaging analysis results were verified by the surface morphology analysis and the energy spectrum analysis. It was found that the main wear area of the electrical connector jack reed was on the end part, and the root part had a small amount of wear debris and the aggregation area was relatively dispersed; with the increase of plugging times, the wear debris between the electrical connector contacts and the wear area gradually increased, and the location of the wear debris accumulation also changed with the plugging movement and was randomly distributed among the contacts; due to machining errors, the jack reed of the electrical connector was asymmetrically distributed, which made the wear degree of different jack reeds different. The results showed that the proposed detection method could effectively observe the charge process of the plug-in wear of electrical connector contacts, and could be used as an effective means for the on-line monitoring of wear degree and residual life prediction of the electrical connector. The research results can provide a basis for the performance degradation mechanism and failure analysis of electrical connectors.

Aiming at the problems that it is difficult to manually repair in the narrow internal space of aeroengine, as well as the weak bearing capacity of traditional continuum robot, a aeroengine blade detection robot was designed. The main body of the robot was composed of multi joint arms, which were connected by universal joints and driven by ropes; a continuum was installed at the end of the robot. In order to improve the end position accuracy of the robot, the closed-loop controller was designed and studied. The kinematics model of the joint arm was established, the calculation formula of the change of the length of the driving rope was deduced, and the method of converting the reading of the inertial measurement unit into the joint angle was introduced. Kalman filter was used to reduce measurement noise, and the best estimated value of joint angle was obtained as feedback. Based on multi-dimensional Taylor network optimal control (MTNOC), a closed-loop controller was designed, the characteristics and advantages of MTNOC controller were analyzed, and the effectiveness of MTNOC controller was verified by simulation and experiment. The results showed that Kalman filter could effectively reduce the measurement noise; MTNOC controller had better adaptability and dynamic characteristics than PID controller, so that the joint arm also had faster response speed at the moment of large state change. Under the control of MTNOC controller, the end position accuracy of blade detection robot was improved, which increased the accuracy and reliability of aeroengine blade detection results.

In order to realize the stable, accurate and efficient underwater docking of autonomous underwater vehicle (AUV), a guide cover opening and closing underwater docking device was proposed. According to the control requirements of AUV docking motion determined by the characteristics of the docking structure of the device, considering that the forward motion played a leading role in the docking stage, the dynamics simulation models of AUV docking system under three application scenarios of static docking, floating docking and towed docking were established respectively. The hydrodynamic force and collision force of AUV docking system when docking were analyzed emphatically. Based on the underwater docking simulation system jointly built by ADAMS (automatic dynamic analysis of mechanical system) and control simulation software MATLAB/Simulink, the simulation analysis and comparison of static docking, floating docking and towed docking effects under different connection control schemes were carried out. The results showed that under the position-velocity closed-loop control, the docking energy consumption, collision times and maximum collision force were the smallest, and the docking time was reduced by about 50% compared with that under the traditional position velocity closed-loop control; under towed docking scenario, the docking system realized good variable velocity tracking under the position-velocity closed-loop control, which was conducive to the rapid docking of AUV. The AUV underwater docking system is suitable for different docking scenarios, which is convenient for unmanned boats to launch and recover AUV, and is more conducive to the innovation of cross-domain cooperative operation mode of ocean unmanned systems.

Aiming at the cumbersome data processing problems of existing metal pipeline weak magnetic signal acquisition methods, based on the weak magnetic signal detection technology, a weak magnetic signal acquisition system integrating data acquisition, data processing and data analysis was built by using HMC1001, HMC1002 magnetoresistive sensors and the STM32F407 chip. Firstly, the acquisition and transmission process of the weak magnetic signal was introduced; then, the hardware of the weak magnetic signal acquisition system was designed, and the filtering algorithm and the compression algorithm were introduced to write the corresponding data processing and analysis program. Through the designed hardware circuit and data processing and analysis program, the functions of acquisition, transmission, filtering, compression, storage and real-time display of the weak magnetic signal of the metal pipeline were realized. The field verification results meet the expectation of the designed weak magnetic signal acquisition system, which show that the system has practical value.

Aiming at the problems of high power consumption of the acquisition unit and the complex wiring in the traditional building energy consumption monitoring system, a low-power wireless monitoring system was designed. The designed monitoring system included acquisition unit, concentrator, monitoring center and communication network. The acquisition unit was mainly composed of the metering circuit and the BLE (Bluetooth low energy) communication circuit, which collected the energy consumption data of electrical equipment through the metering circuit, and sent the processed energy consumption data to the concentrator through the BLE communication circuit. The concentrator was mainly composed of BLE communication circuit and Wi-Fi communication circuit, which received the energy consumption data measured by the acquisition unit through the BLE communication circuit and integrated and processed it, and then forwarded the energy consumption data to the monitoring certer through the Wi-Fi communication circuit. The monitoring center was designed by B/S (browser/server) architecture, which displayed the energy consumption data through the monitoring interface and saved the data in the database. By using the BLE and Wi-Fi communication mode, the designed monitoring system reduced the operation power consumption of the acquisition unit and the wiring complexity, and prolonged the communication distance; the monitoring center designed based on the B/S architecture could realize cross-platform operation and improved the flexibility of the system. The test results show that the measurement deviation rate of the designed monitoring system is lower than 5%, the communication success rate is higher than 98%, and it can monitor the energy consumption of electric equipment in time, which has high practical value.

In the drilling exploration of complex and difficult to drill formations in Sichuan and Chongqing, general hammer bit has some shortcomings, such as low rock breaking efficiency, slow drilling speed, short service life and high operation cost. Therefore, two new types of cemented carbide tooth, i.e. pyramid tooth and half parabolic tooth, were designed. Combined with the tooth structure and engineering practice of the two kinds of teeth, a pyramid tooth-half parabolic teeth hammer bit was designed. Pyramid teeth were arranged on the middle end face of the bit, and half parabolic teeth were evenly arranged on the edge cone. The rock breaking mechanism of pyramid tooth and half parabolic tooth was analyzed. Using finite element simulation method, the comparative study of rock breaking between pyramid tooth and conical tooth, half parabolic tooth and spherical tooth was carried out. The results showed that under impact load and bit pressure, the stress produced by pyramid tooth within the rock was more concentrated than that of conical tooth; compared with spherical tooth, the stress produced in the contact area was more concentrated when the half parabolic tooth cut and extruded rock; pyramid tooth and half parabolic tooth broken the rock easier, and the rock breaking efficiency was improved. The rock breaking simulation of pyramid tooth-half parabolic teeth hammer bit and general hammer bit was carried out. The results showed that compared with general hammer bit, the drilling speed of pyramid teeth- half parabolic teeth hammer bit was increased by 38.3%, and the fluctuation range of axial acceleration of the bit was reduced by 13%. The research results can provide theoretical support for the research and development of pyramid teeth-half parabolic teeth hammer bit.