Wenzhou Vocational & Technical College
Wenzhou Vocational & Technical College
Li Z.,Tianjin University |
Li Z.,Wenzhou Vocational & Technical College |
Shi K.,Wenzhou Vocational & Technical College |
Cui T.,Wenzhou Vocational & Technical College
International Journal of Simulation: Systems, Science and Technology | Year: 2016
Harry-Ward control system is a widely used speed control system of DC motors. In this paper, we propose a fuzzy logic based speed control system further optimized by considering state variables and transfer functions. The simulation is performed using the tool Simulink in Matlab. The fuzzy control method is improved to detect errors of input signals, filter the whole process and change the error signals. The simulation shows that the fuzzy logic controller algorithm gives better performance compared with conventional control, largely reduces the error in speed, and continuously adapts to give a more robust approach to the motor speed control system. Several experiments are performed and we conclude that the proposed algorithm gives higher efficiency of the speed control in motor. © 2017, UK Simulation Society. All rights reserved.
Ye B.,Zhejiang Sci-Tech University |
Ye B.,Zhejiang Province Key Laboratory of Transplanting Equipment and Technology |
Yi W.,Zhejiang Sci-Tech University |
Yi W.,Zhejiang Province Key Laboratory of Transplanting Equipment and Technology |
And 7 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2017
In order to solve the problems of great impact and vibration and poor dynamic performance of incomplete non-circular gear transmission applied in the rotary transplanting mechanism for dryland and rice plug seedlings, the analytic method was used to carry out improvement design for the buffer device of incomplete non-circular gear mechanism. The kinematics and force analysis of the buffer device were completed, and an analysis and design software based on VB platform for the buffer device was developed. The structure design of the buffer device was carried out. The dynamic performance of the transplanting mechanism with the improved buffer device was studied through theoretical analysis. The dynamic test bench of the transplanting mechanism was built and the dynamic tests were conducted for the transplanting mechanism installed with buffer device before improvement and post-improvement respectively. The dynamic test results showed that the maximum amplitudes of bearing force of the transplanting mechanism in X and Y directions were reduced from 365.5 N and 48.4 N before improvement to 345.2 N and 42.2 N after improvement, which were decreased by 5.55% and 12.81%, respectively, while the variances were reduced from 4880.3 and 148.7 to 4516.1 and 126.1, which were decreased by 7.46% and 15.20%, respectively. The test results after improvement were consistent with the corresponding results of theoretical analysis. The improved design of the buffer device was correct and effective, and the dynamic performance of the transplanting mechanism was improved. © 2017, Chinese Society of Agricultural Machinery. All right reserved.
Lin Y.-J.,Wenzhou Vocational Technical College |
Yuan S.,Tsinghua University
Gongcheng Lixue/Engineering Mechanics | Year: 2017
The parametric finite difference method of lines is an effective numerical method for solving the partial differential equations in the domains with curved boundaries. However, for the degenerate lines on the boundary, how rationally to deal with required boundary conditions remains an open problem. This paper resolves the problem and "finds out" the needed boundary conditions on degenerate lines. Taking a two-dimensional Poisson equation as an example, the detailed derivation of related formulas is presented, and the validity, rationality, and accuracy of derived boundary conditions are demonstrated by the numerical results of computational examples. © 2017, Engineering Mechanics Press. All right reserved.
Lang W.,Wenzhou Vocational & Technical College |
Zhao Z.,Wenzhou Vocational & Technical College |
Du H.,CAS Shenyang Institute of Metal Research |
Gao B.,Wenzhou Vocational & Technical College |
And 2 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2015
A novel arc-spot control unit was developed for the arc ion plating (AIP) assisted by multi-mode AC magnetic fields. The impact of the magnetic fields, generated in different modes, on the arc-spot s motion was modeled, simulated in finite element method and tested in growth of TiN-coatings. The simulated results show that the magnetic fields significantly improves AIP performance. To be specific, the axial-symmetric diverging magnetic field pushes the arc-spots outwards; the axial-symmetric arched magnetic field confines the arc-spot trajectory; and the dynamical focusing magnetic field in reversed polarity, driven independently by the coil-currents with differrent wave-shapes, frequencies and amplitudes, drags the arc-spot to the center and increases the ionization rate and ion density because of steady plasma transport and enhanced collision probability, and as shown in the tersted results, its superposition with the diverging and/or arched magnetic fileds is capable of dynamically controlling arc-spot motion, improving arc-spot discharge and reducing particle emission. ©, 2015, Science Press. All right reserved.
Lin Y.-J.,Wenzhou Vocational Technical College |
Yuan S.,Tsinghua University
Gongcheng Lixue/Engineering Mechanics | Year: 2012
Using the function approximation of tensor product, the extended Kantorovich method was successfully applied to three-dimensional problems in the paper and the non-convergence of the iteration procedure using simple function approximation was overcame. Furthermore, the iteration convergence was displayed and high accuracy and efficiency were demonstrated by numerical examples of the three-dimensional Poisson equation.
He Q.,Wenzhou Vocational & Technical College |
You Z.,Wenzhou Vocational & Technical College |
Kong X.,Wenzhou University
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2016
In order to improve the absolute positioning accuracy of an industrial robot, a position compensation method was proposed herein based on closed-loop feedback of the position and orientation of the end effector. The compensation utilized a laser tracker to monitor the position and orientation of the robot, by measuring the optical tooling points (OTPs) fixed on the end effector, and calculated the deviations of the position and orientation by registering nominal coordinates and the measured coordinates of the OTPs. The industrial robot system communicated with the laser tracker system by industrial LAN, and adjusted the position and orientation of the robot according to the deviation data. The experiments attached in end verified the compensation method, which shows that the location errors are reduced to 0.05 mm in maximum, and the orientation errors are reduced to 0.012 degree in maximum. © 2016, China Mechanical Engineering Magazine Office. All right reserved.
Zhang W.-P.,Wenzhou University |
Wang X.-H.,Wenzhou Vocational & Technical College |
He L.-L.,Wenzhou University
Chinese Journal of Polymer Science (English Edition) | Year: 2016
The aggregation behavior of cyclic rod-coil (RC) diblock copolymers in dilute solutions is investigated through dissipative particle dynamics simulation. By varying the rod length and coil length, cyclic RC copolymers in selective solvents exhibit various morphologies, including spherical micelle, vesicle, bilayer disc, and ribbon bundle structure. Compared with the equivalent linear RC copolymer, only spherical micelle and barrel bundle phase are observed. Rod length is the major factor that controls the liquid-crystalline behavior of RC copolymer systems, while the coil length has a secondary effect on the aggregate morphology. The size of rod bundle varies with the coil length, especially for the end-toend ribbon bundle and side-by-side barrel bundle, which are assembled by cyclic and linear RC copolymer solutions. This finding indicates that the ribbon bundle or nanofiber-like structure in cyclic RC copolymers can be obtained by controlling the rod length and coil length, and thus the optical and electrical properties of RC copolymer would be further controlled and optimized. Results illustrate that cyclization of a linear RC copolymer induces remarkable differences in the rod arrangement and aggregation behavior, thereby indicating the competition between interfacial energy, rod orientational entropy, coil stretching entropy, and packing constraints. © 2016, Chinese Chemical Society, Institute of Chemistry, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.
Ye Z.-P.,Jinggangshan University |
Kang H.-J.,Wenzhou Vocational & Technical College |
Yang X.-L.,Jinggangshan University
Chinese Journal of Applied Ecology | Year: 2016
Light-use efficiency (LUE) is an important parameter to assess light energy absorption of leaf. Especially, it is a key factor to affect production and quality of ecosystem. A model of LUE was developed based on a mechanistic model of light-response of photosynthesis. The maximum LUE (LUEmax) and corresponding saturation irradiance (IL-sat) were deduced according to the LUE model. At CO2 concentrations of 350, 450, 550 and 650 μmol·mol-1, the light-response curves of LUE of tomato seedling leaves were simulated. The results showed that the model of LUE described well the response curves of light use efficiency of tomato seedling leaves at four CO2 concentrations. LUE of tomato seedling leaves reached the maximum value at photosynthetically active radiation between 70-90 μmol·m-2·s-1. There were no difference of LUEmax and IL-sat at 550 and 650 μmol·mol-1. Regarding this phenomenon, it was hypothesized that the photosynthetic functions of tomato seedling leaves had acclimated to the low irradiance in greenhouse so that the intrinsic characteristic of light-harvesting pigments such as the effective light absorption cross-section of lightharvesting pigments and ratio of pigment molecules in the excited state to ground state had hardly changed at high CO2 concentrations. © 2016, Science Press. All right reserved.
Li Z.,Wenzhou Vocational & Technical College
Open Cybernetics and Systemics Journal | Year: 2015
Owing to the existence of domestic shoes product design and other technical issues for comfort, this paper raises the feasibility study on children foot measured consumer individuals on the basis of customized products produced. Children customized design shoes will enrich the level of product consumption structure, make up for gaps in the development of the domestic custom shoes, increase the competitiveness of domestic child’s shoes and has a positive meaning to explore the formation of independent product of high and mid grad child’s shoes. © Zhen Li.
Tian Q.,Wenzhou Vocational Technical College
Journal of Information and Computational Science | Year: 2012
Cooperative relaying is an efficient way to combat wireless channel fading and to increase system throughput. When applying cooperative relaying into broadband wireless systems, in which OFDM is employed, resource allocation becomes an important issue. This paper addresses the optimal Power Allocation (PA) and subcarrier pairing in non-regenerative OFDM relay system. First, we present the optimal PA algorithms for four different cases: (1) optimal PA at relay; (2) optimal PA at source; (3) optimal PA at both source and relay with independent power constraint; (4) optimal PA at both source and relay with sum power constraint. Then, based on the optimal PA algorithms, a joint power allocation and subcarrier pairing algorithm is presented, which iteratively utilizes the optimal PA algorithm and the Hungarian algorithm until convergence. The simulation results show that our proposed algorithm can efficiently improve the data rate of OFDM relay systems, comparing with fixed power allocation algorithms and fixed subcarrier pairing schemes. Copyright © 2012 Binary Information Press.