As an important way of the human-computer interaction, the gesture has become the research focus in the control field because of its strong flexibility and convenience. Aiming at the shortcomings of gesture recognition technology for the upper limb rehabilitation robot, combined with the feature combination and sliding window method, a multi-gesture accurate recognition method based on the extreme learning machine (ELM) optimized by the artificial fish swarm algorithm (AFSA) was proposed to improve the accuracy of gesture recognition. Firstly, the surface electromyography measurement system was used to collect the surface electromyography (SEMG) corresponding to eight kinds of gestures commonly used by the human as the signal source of the subsequent classification model, and the SEMG was preprocessed by the denoising technology and the start-stop detection technology; then, the optimal feature combination and the optimal sliding window after dimensionality reduction by the principal components analysis (PCA) were selected; then, the AFSA was used to search the optimal input weight and implicit threshold of the ELM to improve its classification accuracy; finally, the ELM classification model optimized by the AFSA (AFSA-ELM), the back propagation (BP) neural network classification model and the non-optimized ELM classification model were compared to verify the accuracy of the proposed method. The experimental results showed that the average recognition accuracy of the AFSA-ELM classification model combined with the optimal feature combination and the optimal sliding window was as high as 97.4%, which was 3.5% and 1.6% higher than that of the BP neural network classification model and the non-optimized ELM classification model, respectively, which verified the recognition accuracy of the proposed method. The research results can provide a new idea for the gesture recognition, and provide a theoretical basis and reference for the depth analysis of human upper limb movement and the optimization of gesture recognition algorithm for upper limb rehabilitation robots.

The development of highly reliable sealing structure plays an extremely important role in promoting the industrialization of incineration ash treatment equipment. Based on the analysis of the existing sealing structure, a double sealing mode combining main sealing and auxiliary sealing was proposed by using TRIZ (Teoriya Resheniya Izobreatatelskikh Zadatch, i.e. inventive problem-solving theory). The sealing structure of incineration ash treatment equipment suitable for remote control was innovatively designed, which effectively solved the sealing problem of incineration ash treatment equipment. The performance evaluation index and calculation formula of the new sealing structure were established, and the sealing performance was analyzed according to the service conditions of incineration ash treatment equipment. The finite element analysis method was used to simulate and analyze the sealing structure, and the final innovative scheme was determined through parameter optimization. The practical application result showed that the designed new sealing structure can meet the level 4 standard of hourly leakage rate, and the alignment accuracy between the docking platform and the standard steel barrel was relatively high. Compared with the existing sealing structure, its overall performance had been significantly improved and had been well applied in incineration ash treatment equipment.

Taking the rehabilitation training of triceps surae as the application background, the rehabilitation effect of slider rocker mechanism on triceps surae was studied. The vector equation of the slider rocker rehabilitation mechanism was deduced, its mathematical model was established, and the motion simulation of the slider rocker rehabilitation mechanism was carried out by MATLAB software. The results showed that the movement of the end effector could be indirectly controlled by controlling the displacement, velocity and acceleration of the slider of the mechanism, so as to form a rehabilitation mode that could meet the different needs of patients; in order to ensure the safety of slider rocker rehabilitation mechanism in use, the variation range of slider displacement should be 200-700 mm. The massage experiment of slider rocker rehabilitation mechanism on triceps surae was carried out. The results showed that after using the slider rocker rehabilitation mechanism, the surface electromyogram (EMG) of the triceps surae changed significantly. There was a significant difference in the EMG values of the triceps surae before and after use (p₁=0.037<0.05), and there was a significant difference in the peak values of the EMG value during use (p₂=0.018<0.05), indicating that the mechanism had a significant and effective rehabilitation stimulation to the triceps surae. The research results can provide a theoretical reference for the application of slider rocker mechanism in rehabilitation medicine.

The dynamics characteristics of tool tip directly affect the cutting stability and the quality of machined surface. At present, the theoretical research and experimental research on the dynamics characteristics of tool tip under the spindle running state have some limitations, such as complex modeling and expensive equipment. Therefore, the identification method of dynamics behavior differentiation characteristics of tool tip under spindle running operation based on semi-theoretical method was proposed. In this method, the differentiation characteristic identification was transformed into a kind of optimization design problem, that was, taking the dynamics characteristic parameters of tool tip at different rotational speeds as variables, and taking the minimum summation of deviations of between the experimental calibration value and the theoretical prediction value of the limit cutting depth and flutter frequency as the objective, the optimization model was constructed and solved with the help of the particle swarm annealing optimization algorithm. Therefore, the dynamics behavior differentiation characteristics and laws of tool tip at different rotational speeds were obtained. Taking a vertical machining center as the platform, the proposed identification method was verified by variable cutting depth milling experiment. The results showed that the calibration value of limit cutting depth was in good agreement with the predicted value. Without complex modeling and expensive experimental equipment, the proposed method can accurately predict the dynamics behavior differentiation characteristics of tod tip, and can accurately predict the cutting stability, which can provide a theoretical basis and data support for further improving the milling quality and efficiency.

In order to study the grinding accuracy of the carbon brush grinding device, taking the self-developed carbon brush grinding device as the platform, the carbon brush grinding and forming removal model was constructed based on the Archard model, and the prediction formula of carbon brush grinding and forming removal rate was obtained, so as to obtain the grinding times of carbon brushes with different removal lengths in the transverse and longitudinal directions. Then, based on the developed carbon brush grinding device, the orthogonal experiment of carbon brush grinding and forming and the verification experiment of carbon brush grinding and forming removal model were carried out. The results showed that the factors affecting the grinding and forming effect of carbon brush were sorted in descending order of the influence degree, followed by the elastic coefficient of compression spring, the mesh number of sandpaper and the pulse frequency of grinding wheel stepping motor; the carbon brush grinding times obtained based on the established removal rate prediction formula were more accurate, which could ensure the grinding efficiency of carbon brushes. The research results provide theoretical guidance and experimental basis for the further development of different types of carbon brush grinding devices.

Pedaling weeding is an effective weeding method in the organic paddy field, and the simulation analysis and evaluation for this weeding process can provide important reference for the design of weeding robots. Taking the pedaling weeding robot as the research object, based on the SPH (smoothed particle hydrodynamics) algorithm in the ANSYS/LS-DYNA software, the finite element model of the robot pedaling weeding process was established, and the multi-phase coupling relationship between the weeding robot and the soil layer and water layer of the organic paddy field was analyzed, and then the dynamic process of pedaling weeding was simulated. Based on the mechanism of pedaling weeding, the factors affecting the pedaling weeding effect were analyzed, and a comprehensive evaluation method of weeding effect was put forward. The effects of robot mass, motion speed and water layer thickness on the pedaling weeding effect were studied based on the simulation and experiment, and the reliability of the constructed finite element model and the effectiveness of the proposed evaluation method were verified by comparative experiments. On this basis, orthogonal simulation experiments were carried out to analyze the influence degree of robot mass, motion speed and water layer thickness on the pedaling weeding effect. The results showed that the multi-phase flow coupling model between the weeding robot and soil layer and water layer could well describe the dynamic process of pedaling weeding. The primary and secondary order of the influence of three factors on the pedaling weeding effect was as follows: robot motion speed, water layer thickness and robot mass, and reasonable configuration of these working parameters could improve the weeding effect. The research results enrich the dynamic modeling method of multi-phase flow and provide a basis for the selection of operation parameters of weeding robots.

After fracturing, the soluble ball seat does not need drilling operation, and can dissolve itself to achieve full bore. Therefore, it has become a key tool for horizontal well piecewise volume fracturing. The sealing performance of sealing ring of soluble ball seat determines the success or failure of horizontal well fracturing operation. Therefore, the simulation analysis of sealing performance and structural optimization of sealing ring were carried out. The working principle of sealing ring of soluble ball seat was analyzed, and its sealing performance was analyzed by finite element simulation method. The results showed that the maximum stress of the sealing ring reached 182.26 MPa after setting, which made it at risk of local damage. The material and structure of sealing ring were optimized, and the effects of structural parameters on sealing performance were analyzed. After optimization, the soluble ball seat could be set safely under the action of 50 kN setting force. The maximum contact stress between the sealing ring and the inner wall of sleeve, sliding body was greater than the fracturing fluid pressure, and the contact stress distribution was relatively uniform, meeting the sealing requirements. After the optimization of the sealing ring structure, the sealing and safety performance of the soluble ball seat have been improved. The research results can provide reference for the improvement of the structure of sealing ring of soluble ball seat.

The static tension condition of safety belt and the dynamic collision condition of luggage compartment are two important conditions in the automobile seat safety regulations. On the premise of meeting the requirements of safety regulations, in order to realize the lightweight design for automobile seats, a lightweight design method of seat frame based on multiple working conditions was proposed. Taking the automobile seat safety regulations as the design criteria and taking the minimum mass of seat frame as the design objective, the size of key components of the seat frame was optimized by comprehensively considering the static and dynamic working conditions. Firstly, the finite element model of the seat frame was established, and the sensitivity analysis was carried out with the seat frame mass as the response, and the design variables for the size optimization of key components of the seat frame were determined; then, the mathematical model of size optimization of key components of the seat frame was established, and the lightweight design for the seat frame was realized; finally, the finite element simulation analysis and experimental research for the optimized seat under the static and dynamic conditions were carried out to verify the correctness of the optimization results. The results showed that compared with the original seat, the weight of the optimized seat was reduced by 7.89% on the premise of meeting the requirements of safety regulations, which verified the effectiveness of the proposed lightweight design method. The research results can provide reference for the safety analysis and lightweight design of automobile seats, which have important engineering practical value.

With the increase of excitation frequency, the vibration amplitude of traditional electro-hydraulic vibration cylinder decreases sharply, and the amplitude compensation performance becomes worse. A double spring electro-hydraulic vibration cylinder structure was designed to solve this problem. The working principle of double spring electro-hydraulic vibration cylinder was studied, its mathematical model and AMESim simulation model were established, and the effects of excitation frequency and compensation spring stiffness on displacement of its piston rod were analyzed. The results showed that when the excitation frequency was 28 Hz and the compensation spring stiffness was 31 N/mm, the displacement of piston rod of the vibration cylinder could be increased by 6.24 mm, which was more than 15 times higher than that of the traditional electro-hydraulic vibration cylinder under the same conditions; in the working process of the double spring electro-hydraulic vibration cylinder, the displacement amplitude of piston rod had an oscillation region and a stable region. The amplitude in the stable region directly determined the quality of the amplitude compensation effect; when the compensation spring stiffness was certain, the displacement amplitude of piston rod did not have a simple positive or negative correlation with the excitation frequency, and the resonance phenomenon was the most obvious at a certain excitation frequency, which could optimize the amplitude compensation effect; there were different compensation spring optimal stiffness at different excitation frequencies, with the increase of excitation frequency, the compensation spring stiffness should increase accordingly. Compared with the traditional electro-hydraulic vibration cylinder, the vibration amplitude of the double spring electro-hydraulic vibration cylinder is greatly improved and can achieve better amplitude compensation effect in engineering applications.

Mechanical automatic vertical drilling tools have the advantages of high temperature resistance, low cost and wide application range, and they have broad application prospects in the field of deep resource exploration. However, the pure mechanical structure causes their deviation correction accuracy to be easily disturbed by the external environment. In order to further improve the deviation correction accuracy of the mechanical automatic vertical drilling tool, the control performance of the drilling tool stabilization platform under different intensities of stick-slip vibration was studied. Firstly, through constructing a mathematical analysis model for the control performance of the drilling tool stabilization platform, the factors influencing the control performance of the stabilization platform were summarized. Then, the multi-rigid body dynamics simulation model of the drilling tool stabilization platform under the stick-slip vibration was established by using the ADAMS (automatic dynamic analysis of mechanical systems) software, and the control precision and control efficiency of the stabilization platform under different influencing factors and vibration intensities were analyzed. Finally, the recommended values of influencing factors when the control performance of the stabilization platform was optimal were obtained through the comprehensive analysis. The analysis results showed that the PDC (polycrystalline diamond compact) radius had the greatest influence on the control accuracy of the drilling tool stabilization platform, while the filling density had a minimal influence on that; the mild and moderate stick-slip vibration had a little effect on the control efficiency of the drilling tool stabilization platform, and the severe stick-slip vibration could greatly improve the control efficiency, but the stick-slip vibration intensity had almost no effect on the control accuracy. The research results can provide reference for the optimization design of mechanical automatic vertical drilling tools under the stick-slip vibration.

As an important bearing mechanism of the aircraft, the landing gear plays a very important role in the process of aircraft take-off and landing. The landing load of landing gear refers to the ground load borne by the landing gear at the moment of aircraft landing, which can be divided into tire contact point load, wheel axle point load and intersection load according to different positions. Changes in the distribution of the design weight of aircraft (including empty weight, commercial load and fuel weight) will affect the landing load of landing gear. Taking the landing gear of a typical civil aircraft as the research object, the landing analysis for the landing gear model was carried out based on the virtual prototype technology. Firstly, the HyperMesh and MSC.Nastran software were used to pre-process and simplify the aircraft landing gear model. Then, according to the requirements of relevant items of airworthiness standards for transport aircrafts in China’s civil aviation regulations, the corresponding working condition parameters were set up and the landing gear landing dynamics simulation was carried out in the MSC.ADAMS software, so as to research the influence of the change of weight and gravity center of the aircraft on landing gear wheel axle point landing load under different fuel densities. By comparing the simulation results, it could be found that the change of weight and gravity center of the aircraft had a significant influence on the wheel axle point landing load of landing gear, while the change of fuel density had a weak influence on the wheel axle point landing load of landing gear. The research results can provide reference and guidance for the targeted calculation of landing gear landing load in the future.

The unpowered exoskeleton has the advantages of small mass, low metabolic energy consumption, basically no change in normal gait, no need for external power source and long sustainable working time, which has gradually become a research hot spot in the field of new exoskeletons. In order to improve the gait energy utilization efficiency of the conventional unpowered lower-limb exoskeleton, a unpowered lower-limb exoskeleton with muscle strength synergistic compensation was designed. Firstly, the energy change law of lower limbs during walking was analyzed by establishing a human lower limb dynamics model, and the mechanism of storage and release of gait energy was obtained; then, combined with the polyline path with substitute start and end point and the muscle strength contribution, the muscle strength synergistic compensation path of the joint muscle was formulated; finally, based on the stiffness of ankle and hip joint, the elastic energy storage elements were designed to construct an unpowered flexible lower-limb exoskeleton, and the OpenSim software was used to analyze the metabolic energy consumption of human lower limb muscles during walking with or without wearing the exoskeleton. The results showed that when wearing the unpowered lower-limb exoskeleton, the metabolic energy consumption of soleus, gastrocnemius and anterior tibial decreased by 31.5%, 34.7% and 40.0%, respectively, and the metabolic energy consumption of rectus femoris, tensor fascia lata and sartorius decreased by 36.3%, 7.0% and 5.0%, respectively; the total metabolic energy consumption of the related lower limb muscles decreased by 15.5% in a single gait cycle. The research results can provide a theoretical basis for the optimal design of unpowered lower-limb exoskeleton with low metabolic energy consumption.

In view of the problems of dimensional errors and appearance defects of VVT (variable valve timing) engine rotors on the current industrial production line, most factories use manual methods to measure dimensions and detect defects, but the accuracy of manual measurement and detection is easily affected by the external environment and subjective consciousness, which may lead to over inspections and missed inspections. Therefore, a VVT engine rotor defect detection system based on the machine vision was designed. First of all, aiming at the interference of bump points on the outer edge of the VVT engine rotor boss on the outer diameter measurement, a bump point detection algorithm based on the gradient feature and position sequence was proposed. The bump points on the boss outer edge were screened and removed by analyzing the distance-position sequence and gradient-position sequence curves of contour points, and then the least square method was used to fit the selected contour points to realize the outer diameter measurement. Then, aiming at the defects such as scratches on the end face of the VVT engine rotor, a SVM (support vector machine) classification algorithm based on the improved HOG (histogram of oriented gradient) feature was proposed. The connected domain analysis method was used to obtain the target region to be detected, and then the improved HOG feature of the target region was extracted, and the SVM was used for classification, so as to realize the detection of end face defects. The experimental results showed that the absolute accuracy of the designed defect detection system could reach 0.01 mm when measuring the outer diameter of the VVT engine rotor, and the bump points on the boss outer edge could be accurately selected; because the improved HOG feature was better than the traditional HOG feature, the designed defect detection system had relatively low over detection rate and missed detection rate in detecting rotor end face defects. In conclusion, the VVT engine rotor defect detection system based on the machine vision can achieve accurate measurement of outer diameter and effective detection of appearance defects, which basically meets the requirements of industrial detection and has relatively high practical value.