International Journal of Applied Electromagnetics and Mechanics - Volume 53, issue 4

Authors: Hasan, Alfaisal A.

Article Type: Research Article

Abstract: The electrodynamic stability of a dielectric selfgravitating streaming fluid cylinder, density ρ^e, ambient with a different dielectric selfgravitating streaming fluid, density ρ^i, has been discussed. The problem is formulated, the governed basic equations are solved and upon appropriate boundary conditions the dispersion relation is derived and discussed analytically and the results are verified numerically. The electrodynamic force has very effective effect on the dielectric streaming system and this is physically explained. The streaming has a strong destabilizing influence for all short and long wave lengths. The stable and unstable states are depending on ρ(=ρ^e/ρ^i) an ρ < 0.5 there …will be stable and unstable domains but when ρ > 0.5 the system is totally unstable with infinite maximum growth rate. The gravitational instability of the present model will be suppressed. Show more

Keywords: Electrodynamic, selfgravitating, streaming

DOI: 10.3233/JAE-160084

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 715-725, 2017

Authors: Li, Junfeng | Yin, Haibin | Tan, Yuegang

Article Type: Research Article

Abstract: The purpose of this research is to present a new kind of soft finger which can achieve variable stiffness actuation by heating the fixed SMA fibers. First, the material and design method of the soft finger are described. Next, the stiffness of the finger with different heating currents for the SMA is measured and the results show the increase of stiffness around 21.5 per cent from the low stiffness to high stiffness. Finally, the maximum pulling force of the soft gripper with variable stiffness is measured, which demonstrates that output force of the finger's tip can be adjusted by changed …stiffness. This variable stiffness structure for a manipulator could greatly benefit applications such as human-safe robotics and systems in which robots need to exhibit high flexibility to conform to their environments. Show more

Keywords: Variable stiffness, SMA actuator, gripper

DOI: 10.3233/JAE-160091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 727-733, 2017

Authors: Wang, Xiaoguang | Zhang, Xiao | Zhao, Xuan

Article Type: Research Article

Abstract: Magnetic bearing with redundant structure can regain supporting ability by way of reconstruction under the condition of coil failure. In this paper, the influence of parameters on stiffness is studied by way of simulation and experiment using PID control algorithm, and the reconstruction strategy is proposed. The range of feasible parameters of redundant reconstruction is determined and the weight of the parameters is found out. The control parameter that makes stiffness of magnetic bearing constant is found out. The experimental results are in agreement with the simulation results in tendency, but the experimental results are less than the simulation results.

Keywords: Magnetic bearing, coil failure, reconstruction stiffness, PID control algorithm

DOI: 10.3233/JAE-160095

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 735-743, 2017

Authors: Lu, Qinfen | Ma, Xuedong | Huang, Xiaoyan | Ye, Yunyue

Article Type: Research Article

Abstract: Linear switched-flux permanent-magnet machines (LSFPMMs) exhibit high thrust force density and low cost, which is especially suitable for long stroke application. They have big normal force so that the assembly becomes difficult. The mechanical flux adjuster is a suitable method to lower the big normal force. This paper investigates the performances of two kind odd primary pole LSFPMMs with mechanical flux adjuster based on FEA, including E- and C-core structure. The analysis results show this method can effectively lower the magnetic field in air gap. The structure parameters of mechanical flux adjuster are also optimized, and the operating curves are …calculated with or without mechanical flux adjuster. With this method, not only does the assembly become easier, but also the operating range extends at small load. Show more

Keywords: Linear machines, longitudinal end effect, mechanical flux adjuster, odd primary pole, switched-flux

DOI: 10.3233/JAE-160104

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 745-756, 2017

Authors: Huang, Yunkai | Guo, Baocheng | Guo, Youguang | Zhu, Jianguo | Hemeida, Ahmed | Sergeant, Peter

Article Type: Research Article

Abstract: In this paper, an analytical quasi three-dimensional method is used to model an axial flux permanent magnet (AFPM) machine with various eccentricities. AFPM machines (AFPMMs) have various advantages but they are sensitive to geometrical imperfections for manufacturing aspect. The main aim of this paper is to propose a general analytical model to analyze the AFPMMs with various types of eccentricities. The radial and tangential magnetic flux densities in the air gap under healthy condition are obtained via combination of Maxwell's equations and Schwarz-Christoffel (SC) mapping firstly. Next, in order to investigate the eccentricities, equations for air gap length and radii …are deduced. The back electromotive force (EMF) is calculated and compared with those from healthy condition and finite element (FE) analysis, respectively. The results show that the analytical predictions agree well with the FE results. Moreover, using this method has a significantly less time consuming than the 3D FM simulation process, which is a great advantage of this method. Finally, the analytical model is verified via experimental results. Show more

Keywords: Analytical model, axial flux PM machines, back EMF, conformal mapping, double rotor, eccentricities

DOI: 10.3233/JAE-160106

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 757-777, 2017

Article Type: Other

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 779-788, 2017