Aiming at the problems of poor forming quality and long printing time of concrete 3D printing components, a path planning algorithm based on continuous vertex partitioning was proposed. Firstly, the continuous vertex partitioning method based on Hamiltonian circuit was used to divide the print area into several continuous regions to ensure that the print nozzle would not pass the same vertex many times during the printing process, thus avoiding the problem of repeated printing and poor forming quality. Then, the genetic algorithm was used to search each region, and the shortest printing path was determined through iteration and optimization. The experimental results showed that compared with other path planning algorithms, the proposed algorithm could significantly reduce the empty travel and start-stop times of the print nozzle, and shorten the printing time by more than 10%, which effectively improved the forming quality and printing efficiency for concrete components. The concrete 3D printing path planning algorithm based on continuous vertex partitioning solves the problems of poor forming quality and long printing time of concrete components by effectively dividing the print area, intelligentiy searching the shortest path and combining the optimal path, which can provide strong technical support for the development and application of concrete 3D printing technology.

Wind turbine blade is the core component of wind turbines. The blade bolt is not only the part that bears complex stress, but also the part that bears the highest load. In order to avoid potential hazard and economic loss caused by bolt breakage, an axial stress measurement system for in-service bolts based on ultrasonic guided waves is designed, which can achieve accurate measurement of axial stress for various types of bolts. Firstly, the group velocity dispersion curve of ultrasonic guided wave was obtained through numerical calculation, and a linear mathematical model of bolt axial stress and ultrasonic guided wave acoustic time was established based on the Hooke's law and acoustic elasticity effect. The effectiveness of ultrasonic guided wave stress measurement by single longitudinal wave transducer was verified by simulation in COMSOL software. Then, in view of the modal aliasing of ultrasonic guided wave echo signals and the interference of noise on the measured results of ultrasonic guided wave acoustic time in actual measurement, the denoising algorithm based on echo compensation was used to denoise the actual measurement signal. The empirical wavelet transform algorithm was used to decompose the modal of ultrasonic guided wave echo signal, and the cross-correlation method was used to obtain the accurate acoustic time of ultrasonic guided wave modal. Finally, the precise measurement of axial stress for 18 types of bolts within the 30%-90% yield strength was completed through experimental tests, and the relative measurement error was less than 2%. The research results are helpful to improve the bolt assembly process and standardize the worker's operation process.

In order to solve the problems of low efficiency and heavy computational workload during the optimization design process in the existing airfoil geometric parametrized modeling methods, a deep learning-based airfoil parametrized modeling method was put forward. In this method, the two-dimensional airfoil images converted from coordinate points of airfoil upper and lower surfaces in the airfoil database of the University of Illinois at Urbana-Champaign (UIUC) were taken as the input. Firstly, the convolution operations were used to extract geometric features of a large amount of airfoil images. Then, the extracted geometric features were classified and compressed by multi-layer perceptron, and the airfoil shape was compressed into several simplified fitting parameters. Finally, the airfoil image was restored and the coordinates of points on the upper and lower surfaces of airfoil were output by a decoder. On this basis, the influence of the number of fitting parameters on the geometric accuracy of airfoil was discussed, and a convolutional neural network (CNN) structure with six fitting parameters was determined. At the same time, the fitting accuracy of the proposed method was verified by the computational fluid dynamics numerical simulation. Finally, the visual airfoil geometry design software was developed to adjust and modify the fitting parameters, and the influence law of each fitting parameter on the airfoil shape was summarized. The results indicated that all the six fitting parameters had a global impact on the airfoil shape, and the new airfoil design space could be obtained by adjusting the six fitting parameters individually or jointly. This research results can provide technical support and theoretical guidance for airfoil optimization design.

The classical fracture phase-field model is a variational method based on brittle fracture theory, which cannot accurately characterize the quasi-brittle fracture behavior of composite material. Based on this, a multi-phase-field model was proposed to describe the multi-pattern cohesive fracture behavior of fiber reinforced composites material. A hybrid cohesive fracture phase-field model was proposed by reasonably defining the phase-field driving force and the damage constitutive relationship for the anisotropic material, and the corresponding evolution equation and strength criterion were derived. The model was used to simulate the crack propagation and failure of three kinds of composite plates. The results showed that the proposed multi-phase-field model could effectively simulate the multi-pattern cohesive fracture behavior of composite material, and had high application value.

In order to solve the problems of slow movement, poor environmental adaptability and single gait of rescue robots, a quadruped bionic mobile robot was designed according to the physiological structure of turtle and goat. Firstly, according to the characteristics of turtle crawling on soft ground and goat's strong movement ability, two gaits imitating turtle crawling and goat walking were planned for the robot to adapt to different environments and improve the robot's movement performance. Then, the dynamics analysis for the robot outrigger was carried out, and the quantitative relationship between the robot joint torque and motion performance parameters was obtained by establishing a dynamics model. Finally, the feasibility of the robot's gait and the robot's adaptability to the environment were verified by simulation and prototype experiments. The results showed that the designed robot had stable structure and reasonable gait planning, which could adapt to different complex terrains. The research results can provide important reference for the design and development of bionic robots.

Transrespiratory biopsy is a common surgery for diagnosing pulmonary nodules. However, due to the risk of infection of respiratory diseases and joint restrictions during manual operation, the diagnosis and treatment method combined with medical and engineering has gradually become a development trend. In order to realize the flexible movement, precise positioning and stable intervention of the flexible body in the complex bending and dynamic environment of the bronchial lumen, a master-slave collaborative remote control robot mechanism design was adopted to simulate the doctor's operating habits in traditional surgery, and an integrated mechanism principle prototype that could simultaneously control the bronchoscope and biopsy forceps was designed and build, which realized the dual-machine cooperative control for minimally invasive diagnosis and treatment through the bronchus. Then, based on the Cosserat rod theory, the force-position mapping relationship, pose and working space of the flexible end-effector of the robot were simulated and solved by MATLAB software, and the real pose of the flexible end-effector of the robot in the remote minimally invasive biopsy operation through the bronchus was analyzed by experiments, as well as the actual operation effect of the robot, which verified the accuracy of simulation results. The research results can provide a theoretical basis for multi-instrument collaborative control of transnatural duct biopsy.

Detection range and ranging accuracy are the key performance indicators of radar. Under actual service conditions, they are greatly affected by uncertain factors such as internal signal transmission loss and external signal interference of radar system. Improving its accuracy has become an important topic in the field of radar research. In order to evaluate the influence of the above uncertain factors on the radar performance, the uncertainty analysis of radar detection range and ranging accuracy was carried out. Firstly, the radar detection range and ranging accuracy models considering signal transmission loss and signal interference were established; secondly, the interval model was used to quantify the uncertainty parameters to realize the uncertainty measurement under the unified framework of internal and external parameters; then, the accurate response surface models of detection range and ranging accuracy were constructed, and the influence of multi-dimensional parameters on detection range and ranging accuracy was sorted by using Sobol' global sensitivity analysis method; finally, the subinterval decomposition analysis method was used to obtain the radar detection range and ranging accuracy range, and the results were compared with those calculated by Monte Carlo simulation method to verify the effectiveness of the proposed method. Reasonable tolerance and threshold values are set for radar detection range and ranging accuracy, which can improve the efficiency of radar performance analysis and reduce the cost of performance analysis.

The centralized transmission system has a compact layout and close component spacing, which puts forward higher requirements for its NVH (noise, vibration, harshness) control. Taking the centralized transmission system of an engineering machinery as the research object, firstly, the vibration and noise test was carried out, and the principle of gear micro-modification was analyzed. Secondly, the mutual coupling of system modal resonance and gear meshing was considered, the finite element model of the transmission system was established, and the simulation results showed that the simulation results of gear pair contact patches and modes were consistent with the test results, which verified the feasibility of the modeling method. Then, based on genetic algorithm, the gear micro-modification parameters were solved, the optimal design of the gear micro-modification was realized, and the resonance of the system was avoided by modal optimization. Finally, the experimental verification was carried out, and the results showed that the noise of the transmission system sample was reduced to 95.2 dB after the gear modification, which was 4.8 dB lower than that before modification. The vibration and noise of the transmission system can be reduced by using micro-modification and modal optimization method based on genetic algorithm, which provides a reference for NVH control of the centralized transmission system.

Submarine pipelines laid in the seabed are often suspended due to natural or man-made factors such as ocean current erosion and ship anchoring, which can easily cause pipeline deformation, corrosion, damage, cracking and leakage, seriously affecting the safety of pipelines. Aiming at the suspension internal detection for DN200 submarine pipelines, an internal detection robot was designed, and its dynamics analysis was conducted. Meanwhile, a flexible pipeline-soil coupling model was established by combining ANSYS and ADAMS software, and the internal detection simulation analysis for suspended pipelines was carried out. The fast Fourier transform and the short-time Fourier transform were used to process the vibration response signal of the internal detection robot under complex excitation coupling conditions, and the effective identification of the suspended pipeline section was realized by analyzing the vibration acceleration of the robot. The research results provide a new idea for the internal detection of oil and gas pipelines in suspension.

Using aging chamber to screen mechanical and electronic components can effectively improve the reliability of products. The uniformity of the temperature and humidity field inside the aging chamber determines its overall performance, which has a crucial impact on the functionality of the aging chamber. With the goal of enhancing the performance of the aging chamber, the simulation was conducted on the simplified model of aging chamber by using CFD (computational fluid dynamics) software based on the fluid dynamics principle. According to the simulation results, the distribution of velocity field and temperature field inside the aging chamber was determined to optimize the air supply scheme under the combination of different air supply temperature, air supply speed and air supply angle. The orthogonal test method was adopted in the simulation test, with air supply temperature, air supply speed and air supply angle as test factors, and energy utilization coefficient, temperature non-uniformity coefficient and relative humidity non-uniformity coefficient as evaluation indexes. Through range and variance analysis of simulation results, it could be seen that the influence of air supply angle on energy utilization coefficient was the most significant, and the influence of air supply temperature on temperature non-uniformity coefficient and relative humidity non-uniformity coefficient was the most significant. For the three evaluation indexes, three optimal schemes were obtained: air supply temperature of 90 ℃, air supply speed of 10 m/s, air supply angle of 0°, air supply temperature of 90 ℃, air supply speed of 12 m/s, air supply angle of -10°, and air supply temperature of 90 ℃, air supply speed of 8 m/s, air supply angle of 0°. Finally, the temperature and humidity measurement experiment inside the aging chamber was carried out and compared with the simulation results. The results showed that the relative errors between the simulation results and the experimental results were small and within a reasonable range, which verified the reliability and effectiveness of the simulation test. The research is oriented to improve the performance and energy utilization of aging chamber, which can provide reference for the design of similar aging chambers and the setting of air supply parameters.

In response to the lack of quantitative characterization methods of surface morphology in the study of microscopic properties and functional mechanism of scraped surfaces, the 3D-motif method was used to characterize the scraped surface morphology. The scraped surface was measured by using LI-3 contact three-dimensional surface morphology measuring instrument, and the two-dimensional grayscale image of the scraped surface was generated by three-dimensional point cloud data. Then, according to the definition of catchment basin in 3D-motif method, the motif segmentation and merging for the grayscale image of scraped surface were conducted by using watershed algorithm. Taking the overall texture region motif segmentation results of scraped surfaces with different precision levels as the object, the feature saliency was defined, and six motif parameters, including depth, area, direction angle, anisotropy rate, flatness coefficient and feature saliency, were extracted and calculated for the scraped surface on two different area scales (25 mm² and 0.25 mm²). Combined with the distribution of some motif parameters and the change trend of the number of motif, the scraped surface was characterized and analyzed from the dimension and morphology of the morphological features, achieving the complete characterization of the three-dimensional morphology of the scraped surface with fewer parameters. The results can provide a theoretical basis for further analysis of the microscopic properties of scraping surfaces.

The rapid development of automotive manufacturing industry, coupled with the accelerated iteration of vehicle models and component updates, requires the production of automotive components to respond quickly to market demand. Ultrasonic welding workstation is a kind of automatic welding equipment, it still faces some problems such as insufficient universality, low flexibility and low-level intelligence. Therefore, a flexible intelligent ultrasonic welding workstation was designed and developed. The physical system of workstation was constructed by modular design to achieve the universality for different automotive components; the flexibility of welding equipment was improved by adopting various switchable flexible components; the intelligence level of workstation and usability of equipment were enhanced by integrating and applying intelligent technology. The technical parameters of the workstation were superior to those of similar products at home, and efficient, intelligent and flexible production was realized in specific applications. The research results are of great significance for promoting the industrial upgrading of the automobile manufacturing industry.

Cone bit in deep drilling is subject to multiple factors such as high temperature, high pressure, friction and corrosion during deep well drilling, which directly affect the service life of the seal ring, and then affect the life of the bit. Therefore, the sealing test technology of cone bit was studied. Firstly, the sealing test machine of cone bit was designed, and its functional modules were designed; secondly, the sealing performances of O-shaped rubber seal ring and radially symmetrical flat rubber seal ring under the influence of multiple factors were analyzed by finite element method, and the contact stress judge criterion and von Mises criterion were used to evaluate and compare the seal ring performances; finally, the life test of the seal ring under the action of multiple factors was carried out, and the experimental results were compared with the simulation results. The experimental results verified the feasibility and reliability of the test machine for cone bit sealing test. The designed sealing test machine of cone bit can predict the service life of cone bit seal ring, and has a broad application prospect in engineering.

Aiming at the problem that it is difficult to obtain the track load of coal mine tracked tunneling robots during driving, a set of four-channel wireless strain acquisition card suitable for collecting dynamic characteristics of tracked traveling structure was designed based on the strain effect of resistive strain gauges and the measurement circuit. Firstly, the circuit and working principle of the strain acquisition card were analyzed. Then, two pairs of strain gauges were symmetrically arranged on the test template, and the strain data collected by DH5902N rugged data acquisition and analysis system was used as the standard to calibrate the sensitivity of four channels in the strain acquisition card through the combination of simulation and test. Finally, the strain acquisition card was integrated and packaged in the tracked traveling structure, and the temperature variation rule of the strain acquisition card under continuous operation in the package environment was discussed. The results showed that the designed strain acquisition card could collect the strain signal of four channels at the same time. Its maximum sampling frequency was 1 000 Hz, transmitting power was 4.5 dBm, and strain acquisition error was less than 5×10^-6. The temperature of the strain acquisition card was stable at 34.58 ℃ after 34.7 h continuous operation in the package environment, which could realize the multi-degree-of-freedom strain signal detection for the tracked traveling structure. The research results provide technical support for real-time acquisition of the dynamic load of tracked traveling structures and the reliability analysis and fault prediction of tunneling robots.

To solve the problem that the traditional constitutive model was not accurate in expressing the rheological characteristics of magnetorheological (MR) fluid, the rheological characteristics of MR fluid were tested by using the MCR302 rheometer, and the relationship between shear stress and shear rate under different magnetic fields was obtained. Genetic algorithm was used to identify the parameters of Bingham-Papanastasiou (BP) model and Herschel-Bulkley-Papanastasiou (HBP) model. The simulation model was established based on the identification results, and the dynamic characteristics of the MR damper were simulated numerically. A MR damper was designed and processed, and a damping force test platform was built to test the damping force, and the experimental results were compared with the simulation results. The results showed that the identification results of the rheological characteristics of MR fluid by HBP model were in good agreement with the experimental results. The prediction results of the two models were quite different in the dynamic characteristics of the damper, but the prediction consistency of the flow rate was good. The predicted value of damping force based on HBP model was in good agreement with the experiment value. The proposed HBP model could express the rheological characteristics of MR fluid with high accuracy and had good practical value. The research results can provide reference for the selection of mechanical model of MR damper in vibration control field.