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.

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.

Aiming at the problems of large changes in longitudinal pitch amplitude and longitudinal pitch angle caused by the flow field when the remotely operated vehicle (ROV) sails at high speed, a method for achieving high speed underdriven ROV operated with zero longitudinal pitch or slight longitudinal pitch by matching and selecting structural parameters of the extended chassis and the tailplane was proposed. Based on the lattice Boltzmann method (LBM), a six-degree-of-freedom simulation experiment was carried out by using the wall adaptive refinement algorithm combined with the structural parameters of the ROV to simulate the ROV sailing motion. The numerical analysis for the ROV with different height of extended chassis and tailplane was analyzed numerically to obtain the relationship between the structural parameters of extended chassis and tailplane and the longitudinal pitch amplitude and longitudinal pitch angle. By comparing the rotating torque of ROVs with similar sailing performance, the relationship between ROV stability and tailplane height was determined under the same extended chassis conditions. The orthogonal experiments for structure optimization of the extended chassis and tailplane were conducted, and the longitudinal pitch data of the ROV under different experimental schemes were fitted by using genetic algorithm. Combined with the actual requirements, the height of the extended chassis and tailplane was determined, and the correctness of the ROV longitudinal pitch design scheme was verified by the actual test. The results showed that the reasonable match of the extended chassis and tailplane structure could effectively reduced the longitudinal pitch amplitude of underdriven ROVs, so as to achieve slight longitudinal pitch sailing motion of ROVs without amplitude compensation. The research results can provide reference for improving the longitudinal pitch motion of relevant underwater devices.

The construction of supporting wheel-track-ground multi-body coupling system is an important link for the travelling smoothness study of tracked robots. Taking the unilateral five- supporting wheel tracked robot as the study object, the theoretical estimation model for tracked robot vibration was established on the basis of the nonlinear suspension system model and the road excitation considering the track filtering effect. Then, based on the simulation experiments of the tracked robot under working conditons with different road levels and different driving speeds, the effects of driving speed and road excitation on the vertical vibration of the robot body and its supporting wheels were quantitatively analyzed by the root mean square value. Finally, the theoretical vibration estimation model and dynamics simulation model of the seven-degree-of-freedom semi-vehicle were verified by external road experiments. The results showed that the vertical vibration of the tracked robot body increased linearly with the increase of driving speed and road roughness, and the track had a filtering effect on the road excitation. The vertical vibration acceleration of the tracked robot body centroid and the supporting wheel 1, 3, 5 were most sensitive to the road excitation, and the power spectral density amplitude of the vertical vibration acceleration of the robot body was the largest when the frequency was about 19 Hz. As the supporting wheel 5 was close to the driving section, the polygonal effect generated by the track engaging with the active wheel made its vertical vibration larger than that of the other supporting wheels. The combination of theoretical modeling, simulation analysis and external experiment provides a new idea for the study of vibration response characteristics of tracked robots under different road conditions.

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.

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 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.

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.

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.

Load is a factor that cannot be disregarded during the running of rolling bearing, and loads with distinct characteristics will exert varying impacts on the reliability of bearing. In response to the stochastic time-varying nature of equivalent dynamic loads borne by rolling bearings, a reliability life evaluation method of rolling bearing considering dynamic time-varying loads was proposed to solve the problem of low evaluation accuracy caused by ignoring the time-varying bearing load in traditional methods. Based on the grey prediction model, the analysis model of the stochastic time-varying process of the bearing equivalent dynamic load was constructed, and the small sample load data was forecasted and supplemented. On this basis, an reliability life evaluation method of rolling bearing based on dynamic stress-strength interference model was proposed, and the working interval of dynamic load was obtained, so as to obtain the bearing reliability life interval. The reliability life test of cylindrical roller bearing NU206E was carried out to verify the proposed method. The results showed that, compared with the traditional method, the bearing life evaluation value obtained by the proposed method was close to the test values with higher accuracy and shorter evaluation time, and the life interval covering the most test values could be obtained. The method combining gray prediction model and dynamic stress-strength interference model has good engineering application value, and provides a new idea for reliability evaluation of rolling bearing under variable load conditions.

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.

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.

Mobile robots can replace people into dangerous environments such as fire and earthquake sites for terrain exploration and casualty search, but most robots are difficult to adapt to obstacles, right-angle walls, wall transitions and other complex terrain at the same time, and their control systems are relatively complex, requiring external energy input. Therefore, a deformable mobile robot with multiple functions, relatively simple control and no tethering was designed. Firstly, taking the 2-bar 4-cable tensioning integral structure as the basic unit, the body of the tensioning integral structure which could realize bending deformation was designed. Secondly, based on the analysis of adsorption force and structural parameters, the negative pressure adsorption device was designed and combined with the deformable body to form the overall structure of the robot. Then, the kinematic analysis of the robot was carried out, and the mapping relationship between the robot pose and the motor angle was obtained. Based on this, the robot's gaits of wall surface transition, traversing the narrow space from the wall surface and flipping up steps were planned. Finally, the robot prototype was developed, and the robot movement experiments were carried out according to different terrain, and the rationality of the robot gait planning was verified. The research results provide a certain reference value for the design and manufacture of multi-functional mobile robots.

Aiming at the difficulties of on-line fault diagnosis of centrifugal pumps in nuclear power plants, a fault diagnosis method based on wavelet pack decomposition and random forest is proposed. Firstly, the wavelet pack decomposition was used to decompose the vibration signal in the radial vertical direction of the centrifugal pump motor drive end into three layers, and the sub-band energy features were extracted. Then, the time-domain statistical features were extracted based on the waveform data of centrifugal pump vibration signal, and combined with wavelet packet energy features as inputs for the random forest model. Finally, the random forest model was trained with centrifugal pump vibration dataset collected from vibration test, and the centrifugal pump fault diagnosis model was formed. This model was compared with machine learning models such as support vector machine, logistic regression, K-nearest neighbor and Gaussian Naive Bayes on the same centrifugal pump vibration dataset. The results showed that the constructed model could accurately identify different operating states of the centrifugal pump, such as normal operation, impeller damage, impeller blockage and motor bearing fault, and exhibited better classification performance. The fault diagnosis method based on wavelet packet decomposition and random forest can effectively extract features from vibration signals and realize fault classification, which has certain feasibility and effectiveness for on-line fault intelligent diagnosis of centrifugal pumps in nuclear power plants.

Aiming at the problems of the traditional triple eccentric butterfly valve to withstand a certain differential pressure or reverse pressure of full differential pressure, an all-metal hard sealing bidirectional zero-leakage triple eccentric butterfly valve is studied and designed. The valve is long-life and energy-saving, and it adopts the triple eccentric principle to solve the defect that the sealing surface of the traditional eccentric butterfly valve is still in sliding contact friction at the moment of opening 10o and closing, which realizes the effect that the sealing surface of the butterfly valve separates at the moment of opening and seals at the moment of closing contact. Firstly, the unbalanced torque and allowable differential pressure of the designed butterfly valve were analyzed theoretically, and the pressure, velocity and flow trace of the fluid in the butterfly valve chamber with different openings were analyzed through fluid flow simulation. The variation curves of the maximum pressure and maximum velocity at the inlet and outlet of butterfly valve with the valve opening were obtained. Then, the thermal temperature and resultant heat flow cloud maps of the butterfly valve were obtained through thermal stress simulation analysis, and the distribution of thermal stress, thermal strain and safety factor of the butterfly valve as well as the variation curve of its maximum thermal stress with fluid temperature were analyzed, which verified that the thermal stress of the butterfly valve met the requirements. Finally, the butterfly valve body pressure test and positive and negative high-pressure sealing test were carried out. The test results showed that there was no visible leakage and deformation of the butterfly valve body, and the measured leakage was zero, indicating that the compressive strength and sealing performance of the butterfly valve met the use requirements. The research results provide a basis for the reduction of contact and friction, the decrease of opening torque and the extension of service life of triple eccentric butterfly valves, and the proposed all-metal hard sealing structure provides a new idea for the research of bidirectional zero-leakage sealing of triple eccentric butterfly valves.

In order to improve the efficiency and quality of thermal battery insulation cotton winding process, an automatic insulation cotton winding system based on digital twin technology was developed. Firstly, the digital twin mapping structure model of the automatic winding device of insulation cotton was created by NX MCD software, and the information interaction and state detection between the model and the actual physical device and control device were realized through TIA Portal software, so as to reflect the winding action and state more accurately. Then, the mechanical model of automatic winding process of insulation cotton was established to analyze the winding mechanism. Nextly, the influence of winding tension and stack rotation speed on the winding effect of insulation cotton was studied by finite element dynamics simulation, and the simulation results were imported into the digital twin system to optimize the digital twin structure layer and control layer program. Finally, the automatic winding of insulation cotton was realized successfully through joint debugging and the thermal battery stack with good coating effect was produced. The research method can effectively improve the research efficiency, accelerate the design process and reduce the trial-and-error cost, which can provide a reference for the research of automatic assembly of winding packaging.

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.

The water-cooled wall of boiler in thermal power plants needs to be inspected and cleaned regularly. Using water-cooled wall robot can improve the efficiency of inspection and cleaning. In view of the complex working environment of water-cooled wall, a new type of water-cooled wall robot was developed. The robot structure and working principle were introduced. In order to ensure the robot to move flexibly and have reliable suction on the water wall, an electric permanent magnet wheel was designed. Through Maxwell simulation and experiment, the current excitation required to magnetize/demagnetize the electric permanent magnet wheel and wheel suction were obtained, and the electric permanent magnet wheel magnetize/demagnetization circuit was designed. The control system of the robot body was introduced, and the experimental platform for lateral walking of the robot was built to verify the cooperation and stability of the robot motion. The experimental results showed that the inner and outer legs of the robot could adsorb and move forward alternately, and realize the gait of lifting, stepping and dropping legs, and the movement was stable. The magnetic force was produced when the robot droped its legs and disappeared when it lifted its legs. The robot had both adsorption stability and movement flexibility. The electric permanent magnet wheel had simple structure, small size, small mass, less power consumption, and could provide about 150 N suction. The research results provide a reference for the application of wall-climbing robot in the cleaning and detection of water-cooled walls.

Coastal blue carbon ecosystems such as mangroves, salt marshes, seagrass beds and seaweed fields are important natural carbon sinks for mitigating global climate change. Under various anthropogenic and natural threats, the coastal blue carbon ecosystems have been degraded on a large scale, so the restoration and enhancement of the carbon sink function of the coastal blue carbon ecosystem is an issue that needs to be solved urgently. According to the categories of coastal ecosystems, the main coastal blue carbon sink technologies and equipment were summarized. The comprehensive benefits of coastal blue carbon ecosystem sink enhancement were analyzed from the aspects of carbon sink enhancement benefit, economic benefit and eco-benefit. Future research should focus on the optimization of the observation system for the distribution and sink of coastal blue carbon ecosystems, the improvement of species optimization and planting methods, as well as the impact of emerging blue carbon ecosystems carbon sequestration technologies on eco-environment, so as to further consolidate and enhance the carbon sink of blue carbon ecosystems s, and help realize the goal of “carbon peak” and “carbon neutrality”.

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.

Aiming at the shortcomings of traditional sliding mode control in trajectory tracking of boom-type roadheader, such as slow global convergence and significant chattering, an improved sliding mode control method based on novel reaching law is proposed. By introducing lateral deviation and heading angle deviation of the roadheader body and adding power reaching term to the traditional exponential reaching law, the rapid convergence of trajectory deviation and chattering reduction for the roadheader were achieved. At the same time, the boundary layer method was employed to further suppress chattering, which addressed the problem of chattering easily caused by the product term of sign functions in the reaching law. The existence, reachability and stability of the novel reaching law were analyzed, and the interval of disturbance steady-state error was derived. Considering the uncertain disturbance of the roadheader, the simulation comparison was conducted between traditional sliding mode control method and improved sliding mode control method. The results indicated that the control accuracy, convergence speed and anti-interference ability of the improved sliding mode control were superior to the traditional sliding mode control. Finally, an experimental platform was set up to test the performance of the roadheader trajectory tracking control system, which verified the feasibility and effectiveness of the improved sliding mode control method. The research results can provide important reference for the intelligent control of mining equipment in the harsh environment of underground coal mine.

In order to solve the problem of oscillation and overshoot of double-rotor structure of magnetic gear compound motor in contactless transmission, a self-tuning vector control method for double-closed loop PI (proportional integral) parameters based on improved dragonfly algorithm (IDA) was proposed. Aiming at the shortcomings of DA in convergence speed and convergence accuracy, Tent mapping, improved weight coefficient and differential optimization algorithm were introduced in the early, middle and late stages of algorithm optimization respectively, and penalty terms that could suppress oscillation and overshoot were added to its fitness function, so that the convergence speed and convergence accuracy of the algorithm were significantly improved. Three control methods of PI, DA-PI and IDA-PI were used for the control simulation and experiment of magnetic gear compound motor. The results showed that the overshoot and steady state error of motor speed under IDA-PI control were the smallest, and the dynamic response speed was the fastest, which proved the effectiveness of the proposed strategy. The research results provide a reference for the control of magnetic gear compound motors with different topologies.

Conventional robotic hands usually require drives to continuously provide torque or force to maintain grasping state. If the drive fails, the robotic hand cannot grasp the object stably. To solve these problems, a passively-triggered bistable robotic hand based on origami is proposed. The robotic hand was composed of a grasping mechanism with single-degree-of-freedom and a driving mechanism with bistable characteristics. Based on the kinematics models of the grasping mechanism and driving mechanism, the structure of robotic hand was designed according to the requirements of grasping state, and the energy barrier could be adjusted flexibly by setting the stiffness parameters of the torsion spring. Finally, the drop capture experiments were carried out to verify the grasping performance of the designed robotic hand. The results showed that when the drop height was 400 mm, the grasping motion of the robotic hand was not triggered; When the drop height was 440 mm, the robotic hand successfully grasped the object; When the drop height was 480 mm, the robotic hand failed to grasp the object although the grasping motion was triggered. The experimental results not only validate the ability of robotic hand to grasp objects of a certain size stably without driving, but also reveal the existence of energy barriers under different external shocks. The passive-triggered bistable robotic hand based on origami has potential applications in passive and adaptive robots.

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.