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In order to improve the performance of bionic quadruped robot, some parameters of leg structure need to be optimized. The kinematic modeling of the leg mechanism of the bionic quadruped robot is analyzed, and the optimization goal is determined. The simulation analyses showed that the improved bacterial foraging algorithm had higher convergence accuracy, and was not easy to fall into local extremum. The improved multi-strategy bacteria foraging optimization algorithm was used to find the optimal leg structure parameters under the original working space. Numerical simulation verifies that the leg structure designed runs smoothly after optimization, which lays a foundation for further research. [ABSTRACT FROM AUTHOR]

The microstructure and properties of 17-4PH/TiC coatings with different boron content have been studied. The calculation result of the JMatPro software is that the addition of B makes the appearance of M2B-type borides in the alloy. The experimental results show that with increasing addition of B, the hardness of the material increases, the friction coefficient and the wear volume decrease first and then increase, and the resistance to corrosion decreases. When the B content was 0.8%, the sample showed a higher hardness (566.3 HV0.3), the smallest wear volume (0.052 mm3), and the highest self-corrosion potential (−0.437 V), which indicated that the composite performance of the composite cladding layer was the best. [ABSTRACT FROM AUTHOR]

A device combining ultrasonic vibration plastic processing technology and single point incremental forming was developed in this work, with maximum power output of 2 kW at frequency of 20 kHz. On this basis, together with theoretical study, experiments and finite element simulation on forming force with aluminum alloy sheet 1060, the results showed that the forming force reduced evidently by appropriate selection of amplitude and frequency, meanwhile, the change of them had a remarkable influence on plastic behavior which can be summarized into two opposite aspects: the softening and the hardening effect. When a lower amplitude and frequency was applied to the forming process, the softening effect dominated, leading to a decrease of forming force, however, under the application of a high-vibrating amplitude and frequency, the harden effect dominated resulting in the decline of plasticity and the increase of flow resistance. The theoretical analytical results and the finite element simulation results are in good agreement with the experimental results, which verified the accuracy of the theoretical model and simulation model. The research results provide theoretical and technical basis for selecting vibration parameters of ultrasonic vibration single point incremental forming. [ABSTRACT FROM AUTHOR]

Low formability, low productivity and forming quality are the main factors restricting the industrial application of single point incremental forming technology. Ultrasonic vibration was introduced into the single point incremental forming process to improve the forming limit of sheet metal by changing the deformation mechanism of material. A device combining ultrasonic vibration with plastic deformation processing technology and single point incremental forming was developed in this work. Taking cone parts of 1060 aluminum as the research object, the effects of ultrasonic vibration amplitude and frequency on equivalent stress and equivalent plastic strain in forming process were analyzed by combining numerical simulation and experimental research. Then, the forming angle of cone parts was used as the standard to study the influence of ultrasonic vibration parameters on formability. The results show that the equivalent stress decreased and equivalent plastic strain increased by superimposing ultrasonic vibrations, ultrasonic vibration can significantly change the formability and improve the forming limit of 1060 aluminum, the forming limit of 1060 aluminum can be maximized by selecting ultrasonic vibration parameters: amplitude 0.03 mm and frequency 30 kHz. [ABSTRACT FROM AUTHOR]

In actual production, shaft parts are affected by the working environment, and are prone to failures such as wear, deformation, corrosion, etc. If the parts that are scrapped due to service damage can be repaired, it can not only save huge economic and time losses, but also It can also improve the utilization rate of resources, in line with the national sustainable development strategy. In this paper, laser cladding technology is used to strengthen the surface of the laser cladding coating for sewing machine shaft parts, and analyze the microstructure, hardness, friction and wear properties of the cladding layer after laser cladding. It is concluded that the average hardness of the cladding layer is about 740.3HV, which is about 2.9 times that of the substrate; the wear loss of the cladding layer is greatly reduced, which are 34%, 40% and 48% of the substrate, respectively, which are less than half of the wear amount. It can be seen that laser cladding on the surface of shaft parts can improve the surface quality of the parts and prolong the service life of the parts. [ABSTRACT FROM AUTHOR]

Single point incremental forming has no support on the back of the sheet, which leads to the defects such as sheet instability and poor forming accuracy. In this paper, isostatic pressing technology is introduced into single point incremental forming process to provide effective support for the back of sheet metal. Taking cone parts with 1060 aluminum as the research object, the forming force under different static pressure parameters was analyzed by finite element analysis and experimental study. The results show that the horizontal forces Fx and Fy increase slightly under static pressure. The axial force Fz has a relatively large change, and with the static pressure increasing, the axial force increases significantly. The experimental equipment of isostatic pressing single point incremental forming was designed to obtain the forming force variation under different static pressing conditions. Compared with the simulation results, the accuracy of the finite element model was verified. [ABSTRACT FROM AUTHOR]

To improve the stability and smoothness of bionic lower extremity exoskeleton walking gait, the elitist mechanism was introduced to enhance the diversity and improve the search ability of the optimal solution. The simulation analyses showed that the improved bacterial foraging algorithm had higher convergence accuracy, and was not easy to fall into local extremum. The improved foraging optimization algorithm was used for the optimization of the bionic lower extremity exoskeleton gait zero moment point stability margin. The simulation results showed that the optimal gait planning method proposed can increase the stability margin and ensure the stable and smooth walking. [ABSTRACT FROM AUTHOR]

Friction characteristics have great influence on forming quality and formability during single point incremental forming. At the same time, the friction coefficient has a significant influence on the finite element model of forming process. In this paper, the friction coefficient of forming process was studied deeply through the combination of theoretical research and experimental research. Firstly, a single point incremental forming mechanical model considering friction was established, and a method to solve the friction coefficient of forming process was obtained. On this basis, the direct relationship between forming parameters and friction coefficient was established by response surface method, and the influence law of forming parameters on friction coefficient was analyzed. The results provided theoretical and technical support for the improvement of friction mechanism and forming quality in single point incremental forming. [ABSTRACT FROM AUTHOR]