International Journal of Applied Electromagnetics and Mechanics - Volume 58, issue 4

Authors: Sun, Zongxiao | Xiong, Linghao | Chen, Qingxiao | Han, Zhimin | Xie, Tianyu

Article Type: Research Article

Abstract: Determining the shape and position of endoscopes has considerable benefits in endoscopic diagnosis and treatment. However, electromagnetic field distortion caused by metal materials, limited field strength and multiple sensors complicate the endoscope localization problem. In this paper, a locally weighted method for the electromagnetic localization of endoscopes that combines the models of the location problem and the errors is proposed. A hardware system, test platform and fixtures are constructed to collect data and evaluate the method. To obtain the global minimum of the objective function, an approach that combines a genetic algorithm with the Levenberg-Marquardt algorithm is developed. Compared to …the localization method without weighting, the results show a 5.3:1 improvement in the localization of a naked coil and a 2.4:1 improvement in the localization of a coil inside a piece of endoscope insertion tube. In a transmitter-tracking configuration that limits the field strength and at a much farther distance (closer than 400 mm vs 400--700 mm), this method performs better than previously reported commercial systems in a similar environment. Furthermore, this method can greatly reduce the influence of metal materials used in endoscopes near the transmitter coil. This method can satisfy the demand for endoscope localization. Show more

Keywords: Electromagnetic localization, endoscope, locally weighted method

DOI: 10.3233/JAE-170150

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 387-410, 2018

Authors: Wang, Shen | Huang, Songling | Wang, Qing | Wang, Zhe | Zhao, Wei

Article Type: Research Article

Abstract: In this work a multiphysics model of a meander line electromagnetic acoustic transducer (EMAT) to generate S0 mode Lamb waves in an aluminum plate is built and the structural parameters of the transducer are optimized based on the model. Three approaches to solve the amplitude of the in-plane displacement component at an observation point are explored and the single frequency approach is selected because it is the fastest. In the optimization, the objective function to minimize is the negative amplitude of the S0 mode waves, and the design variables are the width and height of the magnet and liftoff values …of the magnet and the coil from the top surface of the plate. The liftoff values form a linear constraint of the optimization problem. A genetic algorithm (GA) program capable of handling the linear constraint efficiently is developed. The internal status of the GA program is tracked carefully to avoid unnecessary evaluations of the objective function. With 30 runs of the program, the optimal set of variables leads to the ratio of the width of the magnet to that of the coil of 115.85%. Show more

Keywords: Ultrasonic transducers, meander line electromagnetic acoustic transducers, Lorentz force, Lamb waves, constrained optimization

DOI: 10.3233/JAE-180086

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 411-429, 2018

Authors: Tao, Yaqin | Wang, Jingang | Xu, Zhi

Article Type: Research Article

Abstract: A double differential D-dot overvoltage sensor is proposed based on the D-dot principle for the purpose of faster and more accurate measurement of overvoltage signals. The proposed sensor is a new D-dot sensor structure consisting of four electrodes. It is applied together with the double differential input structure. This structure allows the sensor to operate in self-integration mode and achieve a wide frequency response characteristic while has a stronger anti-interference capability. The simulation demonstration and parameter design are carried out by using the Ansoft Maxwell. A test platform is constructed and used in the steady-state performance and lightning impulse transient-state …test of the sensor. Test results demonstrate that the double differential D-dot sensor has satisfying steady-state performances, manifested by small measurement phase and amplitude errors. It can be applied to internal overvoltage measurement of power system. Moreover, the double differential D-dot sensor is equipped with good transient characteristics. The relative error of the lightning wave rise time which is measured by the double differential D-dot sensor is controlled in the range of ±1.7% and the relative measurement error of lightning wave peak is smaller than ±2.0%. It can measure external overvoltages effectively. Show more

Keywords: Double differential input, D-dot sensor, overvoltage signal measurement, non-contact, Ansoft Maxwell

DOI: 10.3233/JAE-180076

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 431-449, 2018

Authors: Zheng, Li | Qing, Chen | Yu, Xiao | Dixin, Wang | Leiyong, Wang | Qunjing, Wang

Article Type: Research Article

Abstract: Considering the influence of fluid structure interaction and cavitation on the actual deformation of hydrodynamic spherical bearing, the fluid-solid coupling analysis and multiphase flow simulation of spherical bearing for multi-degree-of-freedom motors are realized in this paper. The finite element simulation analysis of the model is carried out by using multi-physical field coupling software. In the study of bearings with and without effects of cavitation, the analysis shows that the peak value of oil film pressure and elastic deformation of spherical bearing decrease when cavitation effect is considered. The oil film pressure increases with the increase of eccentricity, rotation speed, viscosity …and the decrease of the clearance between stator and rotor, which improves the bearing capacity of the bearing, but also intensifies the cavitation in the oil film divergence area and increases the gas volume fraction. And the oil film pressure test platform with different rotational speeds of the spherical rotor is set up, the measured experimental data are in good agreement with the numerical results. In the practical application of the motor, appropriate parameters should be selected, which is helpful to improve the working condition of spherical bearings, ensure the stable operation of bearings and prolong the service life. Show more

Keywords: Spherical bearings, oil film pressure, cavitation, fluid-solid coupling

DOI: 10.3233/JAE-180064

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 451-469, 2018

Authors: Yang, Xiaolong | Chen, Fan | Gao, Shanghan | Chen, Yanhui

Article Type: Research Article

Abstract: In order to meet the high cleanliness and high vacuum requirements of the working environment of the silicon conveyer robot, a new type of concentric biaxial stepped ferrofluid sealing structure is proposed based on the original universal ferrofluid sealing structure. The two dimensional simplified physical model of concentric biaxial stepped structure under axisymmetric condition is established by using the magnetic field finite element method. The nonlinear magnetic field distributions in the ferrofluid sealing structure are calculated and analyzed. The influences of the sealing gap, the width of the pole teeth, the ratio of the permanent magnet length to its height …on the its sealing capabilities were studied. The calculation results were also analyzed and discussed. The results show that the pressure resistances of the concentric biaxial stepped ferrofluid seals significantly decrease with the increase of the sealing gap. Their pressure resistances firstly increased and then decreased with the increase of tooth width. The pressure resistance of the outer diverging stepped ferrofluid seal in the concentric biaxial stepped ferrofluid seal firstly increased and then decreased with the increase of the ratio of the permanent magnet length to its height; Their pressure resistances of inner converging stepped ferrofluid seal firstly decrease and then increase with the increase of the ratio of the permanent magnet length to its height. Show more

Keywords: Silicon conveyer robot, concentric biaxial stepped shaft, ferrofluid seal, key parameters, finite element method

DOI: 10.3233/JAE-180060

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 471-481, 2018

Authors: Liu, Xiping | Zhang, Zhixuan | Xiao, Juanjuan | Xu, Hui

Article Type: Research Article

Abstract: For improving torque density, speed range for constant power operation and overload capacity of the interior permanent magnet synchronous machine (IPMSM) with single-layer PMs, a type of IPMSM with double-layer PMs is designed and analyzed in this paper. Under the same stator structure, winding type and the volume of PMs, the models of IPMSM with single and double-layer PMs are built respectively. The electromagnetic properties including torque, inductance, loss and efficiency are calculated and compared for the two types of IPMSM by FEA. The results show that the salient rate, output torque, the area with high efficiency and speed range …for constant power with double-layer PMs are improved efficiently compared to the IPMSM with single-layer PMs. Show more

Keywords: Permanent magnet synchronous motor, single and double layer permanent magnet, electromagnetic properties, finite element analysis

DOI: 10.3233/JAE-180032

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 483-496, 2018

Authors: Liu, Xin | Sun, Maopu | Chen, Xiaoxia

Article Type: Research Article

Abstract: In toroidal electromechanical drive, torque fluctuation has important influences on the operational performance of the drive system. In this study, the equations of the electromechanical coupled forces and the output torque for the drive are presented by means of electromagnetic theory and mechanical principle. The influence factors of output torque are analyzed. There are periodic changes in output torque and the change mainly depends on the face width angle of the worm and the tooth number of planet. The changes of the output torque are analyzed and classified into four cases. The pulsed and continuous modes of torque change along …with rotating angle are presented as well. The fluctuation ratios of the drive system are calculated quantitatively. Results show that the face width angle of the worm has obvious effect on output torque and its fluctuation ratio. The results are useful for optimal design of the drive and controller design for its periodic fluctuation. Show more

Keywords: Toroidal, electromechanical drive, output torque, fluctuation

DOI: 10.3233/JAE-180010

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 497-512, 2018

Authors: Guo, Rong | Yu, Haitao | Wang, Yao | Chen, Hao | Liu, Xiaomei | Xia, Tao

Article Type: Research Article

Abstract: Permanent magnet synchronous linear motors (PMSLMs) have been widely used in industry applications due to their outstanding dynamic characteristics and improved servo-capability. However, the detent force of PMSLM is an inevitable problem, which causes vibration and affects the positional accuracy of the machine. An improved PMSLM structure with arc-teeth and inner-ladder end teeth (AIL-teeth) is proposed in this study to reduce detent force. This structure is advantageous because it not only reduces detent force but also keeps motor size constant. First, the parameters that affect detent force are confirmed using Fourier analysis method. Second, a hybrid optimization method is adopted …to obtain the structural parameters of the AIL-teeth PMSLM. The hybrid optimization method is based on the flux-tube and Taguchi methods. The optimal structural parameters of the AIL-teeth PMSLM are determined using the optimization method. Finally, two PMSLMs with traditional and improved structures are contrasted by finite-element analysis (FEA) method and experimental verification, results show that the improved AIL-teeth PMSLM can reduce detent force effectively with the least sacrifice of electromagnetic performance. Show more

Keywords: Detent force minimizes, AIL-teeth PMSLM, flux-tube method, Taguchi method, FEA method

DOI: 10.3233/JAE-180047

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 513-529, 2018

Authors: Hao, Du | Li, Decai | Chen, Jiawei | Yu, Jun

Article Type: Research Article

Abstract: The sealing of large diameter rotating shaft in some special applications especially in aerospace and military industry needs to be sealed with magnetic fluids. However, the major problems of restricting the application of large diameter magnetic fluid rotary seal is the decrease of the pressure-resistance capacity of magnetic fluid seal at high temperatures and the bigger breakaway torque at low temperatures. To research effect of the temperature on the pressure-resistance capacity and breakaway torque of large diameter magnetic fluid seal, a sealing device with the diameter size of rotary shaft for 190 mm and the sealing gap for 0.1 mm …was designed. Through the experimental test studied on the pressure-resistance capacity at −55 °C–70 °C and the breakaway torque at −55 °C–20 °C, exploring the influence rules of injection volumes of magnetic fluid and the standing time on the breakaway torque under at −55 °C. The experimental results show that the decrease of the saturation magnetization of magnetic fluid at high temperatures result in the pressure-resistance capacity falls, and the increase of the magnetic fluid viscosity at low temperatures is the key factors which causes the bigger breakaway torque. In theory, the analytical expression of between the viscous drag torque and the temperatures were derived, which could qualitatively explain the experimental rules of between the breakaway torque and the temperature at −55 °C–20 °C. In addition, the breakaway torque of magnetic fluid seal increases as the addition of the standing time and eventually becomes stable at −55 °C, and between the breakaway torque and the injection volumes of magnetic fluid showed a linearly change. Show more

Keywords: magnetic fluid seal, high/low temperature, large diameter, breakaway torque, pressure-resistance capacity

DOI: 10.3233/JAE-180065

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 58, no. 4, pp. 531-550, 2018