Dynamics system for reconfigurable manipulator of uncertainty, based on the fuzzy adaptive algorithm is proposed to approach the systemcontrol law from adaptation to friction and external disturbance, the compensatio...
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As a connective tissue connecting teeth and alveolar bone, periodontal ligament (PDL) has the mechanical properties of nonlinearity, viscoelasticity, anisotropy. In this paper, the pig mandibular central incisors were...
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The finite element simulation for the joints of an exoskeleton robot is conducted in this paper. Using software OpenSim to simulate the normal walking gait of the human body, the motion angle and moment of the human h...
ISBN:
(数字)9781728164168
ISBN:
(纸本)9781728164175
The finite element simulation for the joints of an exoskeleton robot is conducted in this paper. Using software OpenSim to simulate the normal walking gait of the human body, the motion angle and moment of the human hip, knee and ankle joints are obtained. Using the obtained data as the input parameters in the finite element simulation of the simulation software Ls-dyna, the strain diagrams and contact force curves of the circular roller and cam disk were obtained. In this study, three commonly used materials are selected: alloy steel, ductile iron and hard aluminum alloy. Finally, the effects of different materials on the key components of the series elastic actuator are studied.
As an important component of all-electric aircraft, the main propulsion machine is developing towards high energy density, high efficiency and high fault tolerance. In order to improve the energy density of main propu...
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Based on the structure of the joint coordinate measuring machine, the error calibration of the flexible measuring arm is systematically and deeply researched. The straightness error data of the two linear guide rails ...
Based on the structure of the joint coordinate measuring machine, the error calibration of the flexible measuring arm is systematically and deeply researched. The straightness error data of the two linear guide rails are obtained by measuring the high-precision square box. Then, the slope of the straightness error curve is obtained by least squares method, and the verticality error can be also calculated. The parallelism error for two rotation axes can be calibrated by test a precision flat. Its result can be quickly compute based on the sampling data. The proposing calibration methods have low cost, easy operation, high efficiency and small environmental restrictions than external calibration by expensive instruments. The experiment has proved the validity and feasibility of the above method.
Based on the theory of crystal plasticity, coupled with dislocation and lath hardening models, this paper establishes a crystal plasticity finite element model describing the high temperature creep of P92 steel. Open ...
Based on the theory of crystal plasticity, coupled with dislocation and lath hardening models, this paper establishes a crystal plasticity finite element model describing the high temperature creep of P92 steel. Open source software was used to generate lath models with an average size of 350nm, 650nm and 950nm to explore the effect of lath coarsening on the high-temperature creep behavior of P92 steel. The results show that the roughening of the slats increases the rate of creep deformation, resulting in a decrease in the service life of the material. Observing the slat model, it can be seen that the roughening of the slats enlarges the numerical gradient of stress and strain, and aggravates the overall plastic strain of the model. The coarsening of the slats accelerates the movement of dislocations, causing the density of movable dislocations to increase, and at the same time the shear strain amplitude of the slip system increases, thereby reducing the hardening behavior of the material.
Augmented reality (AR) technology is a cutting technology. It can enhance the perception of reality and provide more information of the real world. AR technology is used in many fields, like medical, industry, and edu...
ISBN:
(数字)9781728164168
ISBN:
(纸本)9781728164175
Augmented reality (AR) technology is a cutting technology. It can enhance the perception of reality and provide more information of the real world. AR technology is used in many fields, like medical, industry, and education. In this paper, AR is introduced into engineering drawing course. Engineering drawing course is difficult to learn as it is a knowledge that students rarely contact with. To have a close contact with the models and the views, a convenient AR application (AR app) is proposed in the paper. With the help of the AR app, virtual models and real views are combined well. The models can be moved and rotated by touching the screen. Some videos of model assembly and disassembly can be obtained when scanning the quick response code (QR code). Thus, it is convenient for students to use mobile phone to study engineering drawing effectively. The interactive teaching environment enhances students' spatial thinking and cultivates their sense of innovation.
Electromagnetic desalination system is designed by coupling effect of electric field and magnetic field. By designing the L27(313) orthogonal table as the experimental scheme, the electromagnetic desalination efficien...
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Electromagnetic desalination system is designed by coupling effect of electric field and magnetic field. By designing the L27(313) orthogonal table as the experimental scheme, the electromagnetic desalination efficiency is used as the data of the range R analysis. The main and secondary factors influencing desalination efficiency are as follows: initial seawater concentration(F)>influent flow(G)>interaction of adsorption voltage(D) and magnetic field(E)> interaction of activated carbon pore size(A) and substrate material(B)>interaction of activated carbon pore size(A) and adsorption voltage(D)> adsorption voltage(D)>magnetic field(E)>number of electrodes(E)>substrate material(B)>activated carbon pore size(A).The best combination of seawater desalination is A2B2C1D3E3F1G2. The range R of factor F is 20.53, which indicates that the initial seawater concentration has a highly significant influence on the desalination effect of seawater.
In order to improve the flexibility of the pickup manipulator and solve the problem of picking up small sports balls in training ground such as golfing, tennis, and table tennis, a 5-DOF pickup manipulator structure i...
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Objective: To compare biomechanical behaviors of lumbar lateral interbody fusion with and without posterior fixation. Methods: Three kinds of three-dimensional nonlinear finite element models of lumbar vertebrae (L3-S...
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Objective: To compare biomechanical behaviors of lumbar lateral interbody fusion with and without posterior fixation. Methods: Three kinds of three-dimensional nonlinear finite element models of lumbar vertebrae (L3-S1) were developed: traditional lateral interbody fusion with bilateral pedicle 4 screws and 2 rods internal fixation; only lateral interbody fusion; intact model. The models were supported to a 500N follower load with a 7.5-N.m moment of flexion, extension,lateral bending,and rotation. The change of the range of motion (ROM) and intervertebral disc pressure (IDP) of the surgical segment and adjacent segments are compared. Results: Compared with the intact model, both surgical methods reduce the range of motion at the surgical segment in all motion modes, but have almost no effect on adjacent segments. The addition of fixation induce the further reduction of ROM in the surgical segment, and the ROM is almost 0° in all motion modes except for rotation. While for the model of only lateral interbody fusion, the ROM range from 0.4° to 2.2°. Moreover, the variation of the intervertebral disc pressure in surgery groups are extremely subtle in all the segments and all the postures. Conclusion: Compared to the only lateral interbody fusion,the traditional internal fixation with bilateral pedicle 4 screws and 2 rods for lateral interbody fusion showed more bimechanical stability of the surgical segment. The extra fixation for lumbar lateral interbody fusion is indispensable for surgeon.
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