In order to meet the requirements of rapid research and development (R & D) on complex components of control system in aero-engine, a rapid R & D iterative method which combines the digital model driving and selective laser melting (SLM) additive manufacturing technology is investigated. Through the establishment of the efficient forward R & D mode based on the enabled additive manufacturing, the integrated iterative process and technical path with “design-simulation-manufacturing-verification-certification” chain was broke through and the optimization of function and performance for system level products was achieved. The engineering application practice indicates that this technology promotes the development of aero-engine control system towards the direction of lightweight, integration, high performance and high reliability, and it drives the innovative R & D and application of complex key parts/components, which can not only shorten the R & D cycle, but also reduce the R & D cost, and greatly improve the system R & D efficiency.

In order to alleviate the conflict between computational complexity and accuracy in the design optimization of complex engineering products, a new difference mapping based variable-fidelity approximation modeling method based on least squares support vector regression was put forward, namely LSSVR with difference mapping framework (DMF-LSSVR), in order to achieve a highly accurate approximation model within a limited sample size. Its effectiveness was validated through several engineering cases. The results demonstrate that the proposed DMF-LSSVR achieves high predictive accuracy, which can provide theoretical basis for the design optimization of complex engineering products.

In view of the application of performance evaluation technologies of nuclear grade ball valves is rather difficult, the performance evaluation simulation of nuclear ball valve is studied and the simulation process is customized by using Femap & NX Nastran finite element simulation and the secondary development technology in order to improve the efficiency of product performance evaluation. Firstly, the influence of the connection mode of valve components on the natural vibration frequency of the structure and the calculation model of the axisymmetric sealing specific pressure of ball valves were studied to analyse the validity of evaluation technologies and improve the accuracy of simulation calculation. Then, combined with the secondary development technology, a performance evaluation simulation procedure of nuclear grade ball valves was proposed and the corresponding performance evaluation-aided software for nuclear grade ball valves was developed on the basis of the requirements of the design engineer to evaluate the product performance. Finally, the effectiveness of the performance evaluation technology was verified by using the evaluation-aided software applied to DN100 nuclear ball valve. The results showed that the method could significantly improve the performance evaluation efficiency of nuclear grade ball valve. It also can effectively achieve the rapid and intelligent evaluation process, and provide a reference for the customization of the performance evaluation simulation process of other products.

In order to improve the work efficiency and environmental adaptability of mowing robot, a mowing robot for large airport lawn was designed, which could operate remotely and operate autonomously based on the mobile robot platform. Firstly, high precision differential GPS（global positioning system）was used to collect the location information of airport lawn boundary and obstacle. The airport lawn was divided into a minimum number of convex polygonal working areas according to the collected information. Considering that the mowing robot couldn’t turn around without radius in situ, a round-trip straight path planning algorithm based on traditional circuitous path planning algorithm was proposed, and the analytic equations of path in the convex polygon working area were derived. Secondly, the actual trajectory of the mowing robot was measured by high-precision differential GPS and compared with the planned trajectory, and a interval judgment trajectory correction algorithm was designed. The double closed-loop trajectory tracking controller was constructed by PID control of executive motor and interval judgment trajectory correction algorithm. Trajectory tracking simulation experiment of a mowing robot running along the traditional roundabout path and the straight-line roundabout path was carried out. Finally, taking the self-made lawn mower as an example, the prototype experiment was carried out according to the round-trip straight path running mode. It was found that the mowing robot would automatically turn its head to track the next path when the mowing robot tracked the current path to the bound, which verified the stability of the trajectory tracking algorithm. The missing cutting rate of mowing robot was 46.42% under traditional circuitous path running mode, while the missing cutting rate was 7.15% under round-trip straight path running mode, which was obviously better than the simulation result of traditional circuitous path. The missing cutting rate measured in the prototype experiment was 8.89%, which was consistent with the simulation results. It showed that the proposed trajectory tracking algorithm was effective for the mowing robot. The research results can provide theoretical guidance for the development of lawn mowing robot for large airport lawn.

It is launching a research on the instable problem of the four-wheel wall-climbing robot during the steering process on the vertical wall. First of all, based on the Hertz contact theory that the robot driving wheels interacted with the vertical wall, a friction model for robot was proposed, and then the longitudinal friction, lateral friction and turning resistance torque during the whole steering process of robot driving wheel were solved by using the linear integral algorithm. Furthermore, the dynamics model was used to derive the driving torque relation. The torque values that corresponded to different turning radii, different magnetic adsorption forces and different load weights were calculated by the MATLAB software, which were approximately sinusoidal with the steering angles.Finally, the steering stability experiment of the robot was carried out，and the results showed that the measured and simulated values of the driving torque were basically in agreement. Simulation and experimental results indicated that， when controlling the turning radius to 0 m, adjusting the adherence-based force to 1 000 N and limiting the maximum load weight to 27 kg, the steering stability of the robot could be guaranteed and the instable problem of robot during the steering process could be effectively solved. The study results provide the theoretical foundation for path planning and the steering stability control of four-wheel wall-climbing robot.

In the process of running a large inertia special turntable, the system has some problems such as long response time, easy oscillation and large positional error at the end position, so a method based on full-closed loop + fuzzy adaptive PID (proportion integration differentiation) control is proposed. The multi-turn absolute encoder was added at the actuator of large inertia special turntable to achieve full-closed loop of the control system; the fuzzy adaptive PID control was used to achieve fast adjustment under different loads. In order to study the influence of large inertia on the control system further, a turntable model was established systematically. Turntable control system simulation models based on fuzzy adaptive PID control and common PID control were set up respectively in the MATLAB simulation environment, and turntable test platform was built for verification experiment.Comparing the simulation results of system control performance under different control methods, the common PID control system had a long response time and the system followed the error. The fuzzy adaptive PID control could increase the system response speed by 75% and the system’s following error reduced by 70%. The experimental results showed that the positional accuracy of the special turntable was [-0.2°, 0.2°], which satisfied the design accuracy requirement. By analyzing the simulation results and experimental results, the fuzzy adaptive PID control can effectively improve the system response speed, and the full closed-loop control also can effectively improve system positioning accuracy. The research result provides effective reference data for the design of the turntable control system and promotes high-precision development of large inertia turntable.

In order to improve the identification accuracy of rigid guide fault type, a method based on genetic algorithm (GA) and support vector machine (SVM) was proposed to solve the fault diagnosis problem. Vertical shaft lifting system experimental platform was set up to simulate two typical types of rigid guide fault, and the vibration acceleration signal of the lifting vessel was collected. The vibration acceleration signal was decomposed by empirical mode decomposition (EMD), and the singular values of first four intrinsic mode functions (IMF) were calculated by singular value decomposition (SVD) method as the fault characteristic parameters. The fault characteristic parameter was used as the training set of the SVM, and the optimal values of c and g of the SVM were obtained by the GA parameter optimization method. The new test samples were selected to detect the diagnostic effect of SVM. The experimental results showed that the average classification accuracy of rigid guide fault diagnosis method based on GA-SVM reached 93%. This method can accurately identify the typical fault types of rigid guide, and provide a general and feasible solution for the fault diagnosis of nonlinear and non-stationary complex systems such as vertical shaft lifting system.

To explore the effect of display movement speed on search performance in dynamic visual search tasks, a dynamic visual search experiment was designed to test search performance at the 8 display movement speeds of 0, 2, 4, 6, 8, 12, 16, 32°/s through E-prime software, and paired t-test for reaction time. The experiment result showed that when the display movement speed was not higher than 4°/s, there was no significant difference between dynamic search performance and static search performance, but when not less than 6°/s, the difference was significant, and the difference increased with the increase of the display movement speed. In addition, when the display movement speed was not higher than 8°/s, search performance differences between the different display movement speeds was related to the width Δω of the velocity interval. The larger the Δω, the more significant the difference in search performance. When the display movement speed was higher than 8°/s, there was a significant difference in search performance between different display movement speeds. The average reaction time and error rate in dynamic visual search tasks increased with the increase of the display movement speed. The research results showed that the display movement speed had a significant effect on the search performance, and could provide some references for display movement speed setting of the dynamic interface.

In vehicle positioning and navigation system, real-time and accuracy of positioning are key indexes for intelligent driving. However, there are many problems in traditional positioning and navigation system, such as poor accuracy, high cost and poor robustness and so on. In order to solve these problems above, based on GPS/INS (global positioning system /inertial navigation system), machine vision and ultrasonic radar technology, an intelligent vehicle positioning and navigation system based on multi-sensor fusion (MSF) was designed, which could make intelligent vehicle automatic driving in simple and structured road. GPS/INS technology was used for obtaining geographic coordinates, machine vision technology was used for lane line detection and ultrasonic radar technology was used for road edge detection. What’s more, in order to achieve lane-level positioning and navigation, the data of geographic coordinate, lane line and road edge was fused by this system. Finally, the intelligent vehice positioning and navigation field test was carried out. The result showed that this system met the requirements of lane-level positioning and navigation. As to simple and structured road, this intelligent vehicle positioning and navigation system based on MSF with a simple structure runs well. Therefore, this design will greatly improve the accuracy of positioning and navigation.

In order to reduce the principle error generated in the flank milling process of undevelopable ruled surface, a new optimization method for tool path was proposed. Surface matching method was applied to optimize the initial tool path, and the sequential quadratic programming algorithm was used to solve the surface matching problem. Firstly, the existing tool path generation method was used to obtain the tool axis trajectory surface. Secondly, the envelope surface was achieved by offsetting the tool axis trajectory surface along its normal vector, and the principle error was calculated. The surface matching method based on the sequential quadratic programming algorithm was operated to match the envelope surface with the design surface and a spatial transformation matrix was obtained. Thirdly, an optimized tool axis trajectory surface and its corresponding envelope surface were generated, and the corresponding optimized tool path and the error distribution data were obtained. Finally， the simulation was performed by MATLAB and compared with the surface matching method based on least square method. The simulation result showed that the proposed method reduced the principle error of the initial tool path effectively, which indicated that the proposed method could apply to reduce the principle error in the flank milling process of the undevelopable ruled surface. The research results provide a new technical way to improve the accuracy of undevelopable ruled surface flank milling.

The main beam of bridge crane often adopts the method of combining theory and experience in traditional design, which results in the problems of long design period, large section size of main beam and low utilization rate of materials, and also causes the problem of high design cost and manufacturing cost of bridge crane. In view of the above problems, a serial the algorithm based on the concept of complementary advantages is put forward, which uses two algorithms to recycle multiple times, until the output meets the requirements. By making full use of advantages of the global fast convergence of genetic algorithm (GA) and the high solving precision and good stability of artificial fish swarm algorithm (AFSA) in the small variable range, the AFSA-GA serial algorithm was built by adding a module to narrow the scope of variables in AFSA. Three types of test functions were used to verify the feasibility of AFSA-GA, and the AFSA-GA was applied to the lightweight design of main beam for 50 t/22.5 m bridge crane to verify the practicability of the serial algorithm. The results showed that the AFSA-GA serial algorithm satisfied the practical requirements in terms of solving precision, convergence speed and robustness and had applicability. The engineering verification proves that the AFSA-GA serial algorithm can be applied to the lightweight design of the main beam for bridge crane, which can shorten the design period, reduce the section size and improve the material utilization rate.

The static strength test of car body needs to be loaded by the hydraulic cylinder. Aiming at the problems of the manual adjustment of hydraulic cylinder force with complicated operation and low precision and the bench with low degree of informationization and difficult supervision in the traditional car body static strength test, a measurement and control system for car body static strength test bench was designed based on LabVIEW. The upper computer software of the measurement and control system was developed based on LabVIEW. According to the loading characteristics of the hydraulic cylinder and the requirements for system safety and robustness, the PID （proportion integration differentiation）algorithm was improved and the PID parameters were adjusted based on the adaptive algorithm. The S7-200 SMART PLC（programmable logic controller）was chose as the slave computer to control the hydraulic pump station, and the OPC （object linking and embedding for process control） technology was used for communication between upper computer and slave computer. The test bench information system was developed based on the Ethernet and the information process was designed. The test results proved that the measurement and control system realized the control of the hydraulic cylinder force quickly and accurately with strong safety and robustness, and achieved the goal of remote operation and real-time data acquisition of the hydraulic pump station and information management of the test bench. The measurement and control system can be extended to practical applications that require the automatic control of hydraulic cylinder force and the high informationization of system.

The semi-active crane heave compensator is an energy-saving and high-efficiency equipment for solving the heave motion of a floating drilling platform. However, its related technology has been blocked by foreign companies and there is still a lack of accurate and effective test support in domestic. Therefore, a new four degrees of freedom longitudinal vibration model of drill string under compensation was developed to reveal the heave compensation mechanism of the semi-active crane, and a semi-active crane heave compensation test rig consisting of a mechanical structure system, a hydraulic system, and a control system was designed based on the model. The main design parameters included compensation load, maximum compensation stroke and maximum compensation speed. The comprehensive test capability of the test rig was analyzed in terms of operating condition simulation capability, compensation cylinder load and compensation efficiency. The results showed that controlling the floating crane displacement could significantly reduce the impact of heave motion on the WOB (weight on bit), and the active and passive compensations cylinder respectively bore the dynamic and static loads during the compensation process.Besides, the designed test rig could simulate the compensation conditions that met the actual requirements, and the compensation efficiency was 93.14% on the maximum compensation condition，which demonstrated its favorable testing capability. Moreover, The research results provide a reliable theoretical and experimental basis for the study of the semi-active crane heave compensation technology.

A loading method based on high and low frequency composite vibration was proposed，which is pointing to the fatigue fracture problem of metal pipe structures with stress concentration effect subjected to complex alternating loads. The fracture behavior of metal pipe with V-shaped notch was explored by developing a high and low frequency composite vibration experimental device. Based on the composite vibration characteristics of metal pipes, a composite vibration frequency control curve which could improve the crack initiation rate and expansion stability of metal pipes was proposed. The mechanical system and the computer measurement and control system of the composite vibration experimental device were designed. The vibration fracture experiments were carried out on three different metal pipes of 6061 aluminum alloy, 45 steel and 304 stainless steel with prefabricated V-shaped notches. Meanwhile, in order to compare and analyze the special sections of different metal pipes, a method for measuring and evaluating the quality of pipe sections was put forward, and the geometric accuracy and fracture time of three kinds of metal pipe sections were measured and evaluated. The experimental results showed that the crack of metal pipe would initiate rapidly and expand smoothly under the given linearly decreasing low-frequency vibration load. At the same time, it was found that the fracture time of metal pipe was reduced greatly and the crack initiation rate was accelerated significantly due to the superimposed high-frequency vibration load which led to smaller instantaneous fracture area and smoother section of the pipes. The research results provide important reference significance for the life analysis of metal pipes under complex alternating loads and the anti-fatigue design of metal pipes in engineering applications.

Magnetic cardiogram has a unique advantage in the diagnosis of heart-related diseases. In the development of sensor for measuring cardiac magnetic field (called magnetic sensor the next), it is necessary to test the sensor under the simulated magnetic field environment of cardiac magnetic field. A Helmholtz coil used in the magnetic sensor testing system was designed to generate a dynamic magnetic field with pT magnetic induction and simulate the magnetic environment to meet the testing requirements of a magnetic sensor. According to the principle of magnetic field generation of Helmholtz coil, the magnetic shielding barrel was used to shield the environment magnetic field. Through calculation, the parameters such as coil size, coil turns, wire length and wire cross-section diameter were designed. COMSOL Multiphysics simulation software was used to simulate the static magnetic field distribution uniformity produced by Helmholtz coil and the dynamic characteristics of the magnetic field when the current in the coil changed. The simulation results showed that the designed Helmholtz coil met the design requirements, and could produce the heart-like magnetic field waveform with a magnetic field intensity of about 100 pT, a uniformity of less than 5% and good waveform real-time performance, and provided a good test environment for the measurement of the magnetic sensor. The designed Helmholtz coil can be used to test the magnetic sensor, which lays a foundation for the practical application of the magnetic sensor.

Sprocket is one of the key parts in the transmission part of the scraper conveyor, and its design quality has a direct impact on the transmission performance, production efficiency and working life of the scraper conveyor. Because of the complex processing of the sprocket, the theoretical design of the sprocket plays a decisive role in its actual processing. Therefore, it is very important to study the parametric design of the sprocket. The third party library of WebGL (Three.js) and JavaScript were adopted to develop the parametric design in browser. Taking the common seven tooth sprocket with the size of 14 mm×50 mm as an example, in the design of the chain nest, the sprocket was modeled by SolidWorks and the chain nest structure was analyzed in detail. A new design method of chain nest was summed up. Under the Three.js, the JavaScript parameter control function was compiled, and the parametric design of sprocket was carried out according to the sprocket design standard. And using the Web front-end development, in the LAN (local area network) environment, the Web sprocket database was set up by HTML, CSS and JavaScript language, which was convenient for the user to select and download for production and processing. Through the 3D printing technology, the sprocket wheel was printed and compared with the sprocket used in actual production, and the results showed that there was no significant difference between the model and the actual sprocket, which verified the feasibility and accuracy of the parametric design for sprocket. The results provide a reference for parametric design of other more complex components.