PDC (polycrystalline diamond compact) bit is the main rock-breaking tool in oil and gas drilling field, which has the advantages of high abrasion, high rate of penetration and high rock-breaking efficiency. As a cutting unit, PDC cutter determines the rock-breaking performance of PDC bit. The purpose of PDC bit cutter arrangement is to determine the spatial position of each PDC cutter on the bit, so that the bit has excellent performance and reliable life when drilling and breaking rock. PDC bits designed based on different cutter arrangement technologies show different rock-breaking performance during drilling. Therefore, the PDC bit cutter arrangement technology has been widely concerned by scholars at home and abroad. At present, a large number of scholars have made corresponding research on the cutter arrangement technology of PDC bit since its birth, but there is still a lack of systematic summary. For this reason, based on the literature about PDC bit cutter arrangement technology at home and abroad in recent years, the development process of PDC bit cutter arrangement technology since its birth was summarized, mainly including the early cutter arrangement stage, the classical cutter arrangement stage and the modern cutter arrangement stage. Through analyzing and summarizing the development process of PDC bit cutter arrangement technology, it was pointed out that the cutter arrangement technology of PDC bit in composite PDC bit, compatible intelligent PDC bit, long-life PDC bit, force-balanced PDC bit, PDC bit under impact and vibration and PDC bit in special formation represented the future development trend. The research results can provide some reference for the subsequent research of PDC bit cutter arrangement technology, and are expected to promote the further development of PDC bit cutter arrangement technology.

The diversity of existing workpiece materials and processing methods makes the surface of the workpiece diverse, which makes it difficult for the vision system to accurately recognize the workpiece contour. Therefore, a contour recognition method suitable for different workpiece surfaces was proposed. The workpiece surface was evaluated and classified according to the ratio of texture area to convex hull area. For the workpiece with good surface quality, the high-pass linear filter was used to filter the image, and the edge of the workpiece image was extracted by the difference between the workpiece surface information and the edge information; for the workpiece with poor surface quality, an adaptive contour extraction method was adopted to recognize the image edge. Experimental results showed that the proposed method could better remove noise interference than the traditional Canny edge detection algorithm, and its contour recognition accuracy was higher. The proposed contour recognition method has good adaptability to different workpiece surfaces and has certain application value.

In order to provide high-precision force feedback to doctors in robot-assisted remote interventional surgery, a novel vascular interventional surgery robot with force detection mechanism is designed. It is a master-slave control system, including a convenient master device and a slave device for delivering guide wire/catheter. Firstly, the force detection mechanism of the vascular interventional surgery robot was designed to realize the accurate measurement of axial proximal force and the perception of radial clamping force. Then, based on the dynamics analysis of the vascular interventional surgery robot, a fuzzy PID (proportional integral derivative) controller with online parameter setting function was designed to improve the delivery accuracy and anti-interference ability of the slave device. At the same time, the step signal was selected to verify the fuzzy PID controller. Finally, the physical prototype of vascular interventional surgery robot was built, and the master-slave motion tracking experiment and the detection and evaluation experiment of axial proximal force and radial clamping force were carried out. The experimental results showed that the vascular interventional surgery robot had a motion tracking error of [?0.31, 0.25] mm, could detect the axial proximal force with an average error of 0.12 N, and could sense the radial clamping force of 0.47-4 N. The research results verified the robustness of the designed vascular interventional surgery robot and the feasibility of its force detection mechanism, which can provide a reference for the design and improvement of similar products.

Aiming at the problems of insufficient automation and limited vision and observation angle of existing power tunnel inspection robots, a parent-child automatic inspection robot was designed. Among them, the master machine of inspection robot with mobile function could complete the main routine inspection work, and it had the ability to surmount and avoid obstacles; the slave machine with climbing function could complete the survey task under complex environment and extreme angle conditions. The slave machine and master machine could cooperate to complete the automatic inspection of the entire power tunnel. Firstly, based on the overall functional requirements, the specific form of each module of the inspection robot was proposed, and the hierarchical design of its automatic inspection logic system was completed. Then, the power tunnel operation environment was established in the ADAMS (automatic dynamic analysis of mechanical systems) software based on the virtual prototype technology, and the structure of the inspection robot master machine was optimized by combining the results of kinematic simulation analysis, so as to improve the stability of the robot operating in the tunnel and ensure that the sensors carried by the robot could work normally. The results showed that the inspection robot could run smoothly after the optimization of the master machine structure, the jitter amplitude of the sensor platform was within 5 mm, and all the sensors could work normally, which verified the rationality of the robot design. The relevant theoretical research results can provide reliable technical support for the development of the power tunnel automatic inspection robot physical prototype.

In order to solve the problem of poor cooling effect caused by complex internal temperature field of motorized spindle, a water cooler system for motorized spindle cooling was designed. According to the analysis results of the thermal characteristics of motorized spindle, a water cooler cooling scheme was proposed, the relevant heat transfer parameters were calculated, and the temperature?velocity control model for the motorized spindle was established. Then, the finite element simulation of fluid cooling for motorized spindle was carried out by ANSYS Fluent software, and the simulation results were verified by the motorized spindle cooling experiment. By comparing the simulation results and experimental results, it could be seen that the maximum temperature of the motorized spindle motor stator decreased by 60% and the deformation of the shaft decreased by 70% after cooling. The results show that the water cooler system has a good cooling effect on the motorized spindle, which can provide a certain reference for the research of active thermal control technology of high-precision machine tools.

Support stiffness has an important influence on the meshing quality of the gear pair of automatic transmission. It is of great significance to study the influence of the support stiffness and the tooth surface coating on the meshing characteristics of the helical gear pair. Taking the first helical gear pair of a seven-shift double-clutch automatic transmission as the research object, two rigid-flexible coupling models of the gear shaft system with different support stiffness were established, and the influence of the support stiffness on the meshing characteristics of the helical gear pair under different working conditions was analyzed; the tooth profile and tooth direction parameters of the gear with/without manganese phosphate conversion coating were obtained through the FCL-250H gear precision test bench, and were substituted into the finite element model for simulation analysis; the gear contact fatigue pitting test was carried out to compare the contact fatigue life of the gear before and after the coating treatment, and the strengthening mechanism of the coating was further revealed from the aspects of the gear surface morphology, dynamic performance and running-in performance. The results showed that the support stiffness decreased with the increase of gear shaft span, and the maximum load per unit length of gear and the amount of meshing dislocation were more sensitive to input torque changes; after running-in, the gear with coating was more conducive to meshing, and its fatigue life was improved. The research results provide a reference for the structural optimization of the gear transmission system of automotive automatic transmission and the improvement of the gear fatigue life.

In order to reduce the vibration of vane pump in the process of crude oil exploitation, the operating impact caused by sudden change of acceleration should be eliminated as much as possible. The mathematical model of the stator internal cavity curve was obtained by deducing the octagonal curve equation. The transition curve was fitted by MATLAB software. In order to verify the dynamic performance of the vane pump, an experimental scheme was designed, and the variable speed and variable pressure experiments of the vane pump were carried out. The experimental results showed that at the speed of 500 r/min, the lift reached 23.14 m and the flow reached 2.44 m³/h, which met the design requirements of low speed; the vane pump had certain requirements for external pressure load, and its maximum value could not exceed 0.5 MPa. If this value was exceeded, the vane pump would lose its self-priming performance; with the increase of rotating speed, its flow and noise would increase; as the pressure load increased, the outlet flow increased first and then decreased, and the noise generally increased, but it rose slowly after the pressure load was greater than 0.25 MPa, and the flow in the pump gradually approached 0.At this time, the noise of the pump mainly came from the friction between the vane and the stator. The research results provide a reference for reducing the vibration and noise of the vane pump and further optimizing the structure of the vane pump.

In view of the demand of extrusion force stability control in the process of micro-flow extrusion ceramic slurry 3D printer operation, according to the nonlinear and time-varying characteristics of the printer extrusion force control system, the advantages and disadvantages of the existing extrusion force stability control strategy were summarized, and the neural network structure was embedded in the fuzzy PID (proportional-integral-derivative) controller, so a fuzzy neural network PID stability control strategy for extrusion force was proposed. The strategy was based on a six-layer fuzzy neural network, with the extrusion force deviation value e and the deviation change rate e_c as the input, and the PID controller control parameters as the output, to complete the forward fuzzy control process, and based on the self-learning advantage of the neural network to realize the reverse propagation and online update the neural network weight, to achieve the accurate adaptive adjustment of the extrusion force in the printing process. The Simulink simulation of extrusion force control, the extrusion force control experiment and the blank printing experiment showed that, compared with the traditional PID control strategy, the fuzzy neural network PID control strategy could reduce the overshoot by 20.9%, the extrusion force reached a stable state 90 s ahead of time, the pressure peak value decreased by 12 N, and the pressure valley value increased by 18 N; compared with the fuzzy PID control strategy, the overshoot was reduced by 1.73%, the extrusion force reached a stable state 56 s ahead of time, the pressure peak decreased by 4 N, and the pressure valley increased by 8 N; the fuzzy neural network PID control strategy had certain advantages, which could make the control precision of extrusion force higher, the stability speed faster, the overshoot smaller, the overall shape quality of the printed body better, and could also make the system more robust. The research results provide new ideas and methods for PID control and intelligent control of other industrial equipment.

In order to improve the walking stability of amphibious turtle inspired robot, a dynamics model was established, and a force/position control model was proposed based on the PID (proportional integral derivative) feedback control strategy. Firstly, according to the kinematics model of the robot, the transformation matrix and Jacobian matrix of the outrigger were obtained, and a force transfer model between foot end and hydraulic cylinder was established by the virtual work principle. Then, the Lagrange method was used to model the dynamics of the robot, and the dynamics equation of the outrigger was derived. At the same time, the dynamics simulation was carried out, and the real-time force on the foot end was introduced into the dynamics equation for calculation, which verified the correctness of the dynamics model. Finally, a hydraulic simulation model was built, and the robot motion simulation was carried out in the ADAMS?AMESim?MATLAB co-simulation environment. The simulation results showed that compared with the pure position control mode, the rotation of the robot knee joint under the force/position control mode was more stable, and the power output of the hydraulic cylinder was more stable and the power consumption was less. The research results have reference significance for improving the stability of robot motion, enhancing the robustness of motion control system and improving the overall efficiency of hydraulic system.

In order to explore the difference and similarity of the internal dynamic characteristics of rolling bearings under local fault conditions, taking the NU306 cylindrical roller bearing as the research object, the finite element simulation software ANSYS/LS-DYNA was used to construct the finite element models under normal, outer ring fault, inner ring fault and rolling element fault. Then, the stress, vibration and motion characteristics of rolling element under different fault conditions were obtained. The results showed that when the different components of the rolling bearing failed, the front end stress could lag, and the rear end stress could advance, and the stress change in case of outer ring fault was the largest; when the outer ring failed, the vibration acceleration of the rolling element during passing through the fault area decreased first and then increased, while when the inner ring and rolling element failed, the vibration acceleration increased first and then decreased; the revolution speed of the rolling element was lower than the theoretical revolution speed when the outer ring and the rolling element failed, while the revolution speed was higher than the theoretical revolution speed when the inner ring failed. The constructed finite element model can be used to explore the internal fault mechanism of rolling bearings when different components fail, which can provide a powerful analysis method for further research on the bearing capacity and service life of rolling bearings.

Aiming at the complex internal motion characteristics and interaction forces of cylindrical roller bearings with counter-rotating inner and outer rings, through analyzing the factors affecting the radial clearance of bearing and considering the contact deformation between rollers and raceway and the influence of thermal effect on oil film thickness, the analytical model of bearing was established by the quasi-static method and solved by the Newton-Raphson method; at the same time, the model was used to calculate the roller slip rate to verify the correctness and reliability of the analysis method. Then, the rotation speed variation and contact characteristics of internal components of counter-rotating cylindrical roller bearing under different working conditions were further discussed. The results showed that the rotation speed of roller and the contact load between rollers and raceway increased with the increase of radial load; the rotation speed change of inner and outer rings could make the contact load between rollers and raceway in the loaded area redistributed regularly, and the influence of rotation speed on the minimum oil film thickness was more obvious than that of radial load. The research results can provide a theoretical basis for structure design and heat generation mechanism analysis of counter-rotating cylindrical roller bearings.

In view of the problem that metal shaft parts are prone to stress concentration and fatigue failure under actual complex working conditions, the variation of fatigue life of shaft with V-notch with notch geometric parameters was studied by using dual-frequency excitation system. Firstly, the excitation frequency control curve to promote the initiation of shaft fatigue crack was proposed. At the same time, the Box-Behnken design method in response surface method was used to carry out the experimental design of three factors and three levels of angle, fillet radius and depth of V-notch; secondly, a multiple regression prediction model of fatigue life was established, and the reliability of the model was evaluated by variance analysis; finally, the influence of the angle, fillet radius and depth of the notch on the fatigue life of the shaft was analyzed by using the response surface and contour map, and the prediction model was applied. The results showed that the error between the predicted and experimental values of fatigue life was within 4.2%, the prediction accuracy was higher, and the prediction model was reliable; the influence of the geometric parameters of the notch on the fatigue life from large to small was the depth, fillet radius, and the angle of notch. The interaction of fillet radius and depth had the most significant impact on the fatigue life of shaft. The research results can provide an important reference for the anti-fatigue design of metal shaft parts.

In order to realize online monitoring and fault alarm of cable tunnel environment and improve the intelligent level of cable tunnel monitoring system, a fault warning system based on multi-feature sparrow search algorithm (MSSA) optimized support vector machines (SVM) was proposed. Firstly, the fault data set was preprocessed normalized; secondly, a multi-class SVM model was established, and MSSA was used to optimize the parameters of the SVM, so as to establish the MSSA-SVM model. The trained MSSA-SVM model was embedded in the database server of the fault warning system, and the real-time collected data was monitored and diagnosed online, and the alarm was given in time; finally, the effectiveness of MSSA-SVM model was verified by experiments, and it was compared with sparrow search algorithm (SSA), grey wolf optimization (GWO) and particle swarm optimization (PSO). The experimental results showed that MSSA-SVM model has the highest fault recognition accuracy, and its recognition accuracy could reach 95%. The research result provides a reference for effectively improving the intelligence and accuracy of online monitoring of cable tunnels.

The wheel amplitude transformer is the key component of the rotary ultrasonic internal grinding resonant system, and its design quality directly affects the process effect of ultrasonic grinding. However, at present, the wheel amplitude transformer for internal grinding lacks a relatively complete theoretical analysis model. In order to improve the generality of the theoretical analysis model of wheel amplitude transformers, a theoretical analysis model of the longitudinal resonant wheel amplitude transformer was established based on the non-resonant design theory, and the frequency equation was derived by using the force and displacement continuity conditions and boundary conditions between the vibration elements of the wheel amplitude transformer. Then, the frequency equation was solved by programming and verified by ANSYS finite element simulation analysis. Finally, the longitudinal resonant wheel amplitude transformer was manufactured, and the impedance characteristic analysis test, ultrasonic resonance test and vibration displacement measurement test were carried out to analyze its resonance characteristics. The test results showed that the resonant test frequency of the developed wheel amplitude transformer was consistent with the theoretical design frequency, and the relative error between the test value and the simulation value of the vibration displacement at its output end was 7.83%, which met the requirements of rotary ultrasonic internal grinding and verified the correctness of the theoretical analysis model. The research results provide a convenient and effective method for the design of wheel amplitude transformer in rotary ultrasonic internal grinding.