As direct-drive actuators, permanent-magnet linear synchronous motors (PMLSMs) are widely used in high velocity and precision applications. The detent force, however, can deteriorate the performance even excite mechanical resonance. This paper focuses on a novel force compensation scheme for PMLSM systems through combination of structural design control method. First, due to bandwidth constraint system, eliminating frequency ripples is unfeasible; skewed permanent magnets (PMs) considering...

The uniform magnetic field coil can be placed in the shielding room (MSR) to provide a more accurate source. could generate by conventional design method, but when MSR, uniformity of would affected. analysis model based on cuboid ferromagnetic boundary condition is constructed image method. This paper proposes new method parameters deviation distribution volumes boundary. system shield designed compared with system, which not only solves problem reducing, also further improves field....

This paper presents a high-performance current controller for the permanent-magnet linear synchronous motor considering bandwidth and disturbances caused by parameter variation thrust ripple. First, an improved predictive control (PCC) scheme based on discretized model is proposed to increase bandwidth. Besides time-delay issue, it noteworthy that in PCC method can degrade steady-state response. Through utilizing information of first two sampling periods, strategy overcome such issues at...

The triaxial fluxgate magnetometers (TFMs) are widely used in space exploration, positioning and navigation, geological etc. As a high-precision vector magnetometer, the measurement accuracy will directly determine of obtained magnetic field data. TFM has three kinds own errors measurement: zero offset error, proportional coefficient nonorthogonal error. These cause to deviate from actual value, magnetometer needs be calibrated. At present, calibration method adopted by depends on stability...

In this article, a uniform magnetic field coil with shield is presented and designed to cancel the geomagnetic surrounding noises. First, an analytical model of developed, based on Biot–Savart law traditional images method. Second, in order improve accuracy, influence noninfinite thickness produced by considered using multireflection theory, improved obtained. The verified three-dimensional finite-element method, its accuracy significantly compared previous analysis model. Then,...

In space-borne gravitational wave detection, the remanent magnetic moment of test masses is one primary contributors to residual acceleration noise. During ground phase, precisely measuring under an ultra-weak field crucial for assessing its suitability space mission. this work, we developed a compound pendulum apparatus within shielding room, utilizing pendulum’s periodic motion convert into modulated field. The measurement resolution reaches level 0.2 nAm2.

In this paper, the thermal analysis of a hybrid excitation linear eddy current brake is presented. The air gap flux provided by windings and permanent magnets. Therefore, braking force produced large controllable. But, on other hand, there high heating value in conductor plate; hence, it necessary to analyze characteristics avoid declination performance or even damage device. First, structure working principle are described. Second, analytical model built, then network built taking actual...

This paper deals with design optimization of air-cored permanent magnet linear synchronous motors overlapping windings to achieve high thrust per volume, coils quantity, motor constant, and low ripple simultaneously for ultra-precise positioning stage air-bearing. Based on accurate magnetic field model, parameters such as flux density, inductive electromotive force (EMF), are analyzed. A multiobjective method weight coefficients is proposed by applying the multiple population genetic...

Ultra-low magnetic fields have drawn lots of attention due to their important role in scientific and technological research. The combination a shield an active compensation coil is adopted most high performance magnetically shielded rooms. Special consideration needs be taken the design since significantly affects uniformity field that generated by coil. An analytical model for calculation inside cubic proposed based on generalized image method, which validated finite element analysis. A...

This paper describes a tubular linear motor with special permanent magnet. Then, two kinds of magnet magnetization directions for this are proposed, and the air-gap magnetic field is calculated researched based on finite-element method. Moreover, slotless contrasted that traditional interior axially magnetized motors. Finally, advantages analyzed pointed out.

As known, improving launcher thrust is the goal that mankind pursuing. There no saturation phenomenon in ironless permanent-magnet linear motor (IPMLM); hence, of IPMLM has a relationship with current through windings to provide larger thrust. The topology determines its fluctuation smaller than an iron motor. In this paper, model air-gap magnetic field established by charge and image method for global optimization All dimensions are described thickness three ratio coefficients (i.e., α, β ,...

The key technology of the air-core monopole linear motor (AMLM), a core component precision motion systems, is distribution electromagnetic structure and cooling structure. Thus, AMLM can achieve small thrust fluctuation, high density, low surface temperature rise. Consequently, multiobjective optimal design under multiphysical fields has become AMLM. Consideration strict requirements model calculational accuracy will cause an excessively long computation time for finite-element analysis...

To enable the realization of weak magnetic field at level several nanotesla, a magnetically shielded room (MSR) is required to create space with residual below 1 nT. Since by inner shielding shells very low, permeability materials in this range measured. As gaps between ferromagnetic material strips wall lead considerable reduction factor, new numerical model evaluate equivalent discontinuous layers proposed and demonstrated experimentally. Based on property lower normal range, improved...

A sectioned-winding permanent-magnet linear synchronous motor (SW-PMLSM) is proposed in this paper, whose iron core continuous, whereas winding divided. The model of the SW-PMLSM derived after section structure and distribution are introduced. basic theory implementation current error vector-based predictive control (CEVPC) space-vector pulse-width modulation deadbeat-predictive (SVPWM-DBPC) proposed. moving stroke divided into five zones according to position secondary, implementations for...

The scalar triangulation and ranging (STAR) method is a magnetic detection based on gradient tensor invariants, which has wide application prospect. Due to the asphericity parameter, there are distance error direction in STAR method. There have been studies compensate error, but not compensated. This article proposes new (NSM) that uses an iterative both error. Considering convenience feasibility of operation, previous researchers analyzed accuracy by target latitude trajectory (latitude...

The magnetic characterization of a spacecraft plays crucial role in ensuring cleanliness for various space exploration missions. When conducting the characterization, environmental noise traditional coil facilities (MCF) can significantly reduce accuracy model predictions by influencing measured field data. Therefore, equipment shielded room (MSR) is conducted this paper to address above issue. However, generated may undergo distortion within MSR due presence high-permeability materials...

To enable the realization of ultra-low magnetic fields for scientific and technological research, shielding is required to create a space with low residual field high factors. The factors shields are due nonlinear material properties, geometry structure shields, external fields. Magnetic used in environments full random realistic disturbances, resulting an arbitrary field, this case, effect hard define simply by A new method simulate predict dynamic internal wave proposed based on Finite...

With the increasing requirements for miniaturization and high braking torque, it is now necessary to analyze thermal characteristics same extent as electromagnetic design eddy current brakes. However, due lack of suitable convection heat transfer correlations axial flux brakes, brings difficulties designers. To solve this problem, an permanent magnet (PM) brake are derived using computational fluid dynamics (CFD) least square method. The proposed considered changes in parameters temperatures...

In this paper, the analytical model of a permanent magnet (PM) linear eddy current brake is presented with consideration transverse edge effects. The effects can be divided into static and dynamic effect caused by diffusion magnetic flux in core edge, paths currents conductor plate. First, structure working principle are described. Next, air gap analyzed using multilayer analysis conformal mapping method. braking force then calculated while taking consideration. Finally, validity verified 3D...

Uncertain data mining has recently attracted interests from researchers due to its presence in many applications such as Global Positioning System (GPS) Wireless Sensor Networks (WSN), Moving Object Tracking. This paper is researching uncertain clustering problem, almost all the existed algorithms of calculate expectation express distance objects, so they can cluster like certain data. But neglect distribution objects and consume much more running time expectation. In paper, we propose...

The analysis of a flat voice coil motor (VCM) with Halbach array structure is described. applied for precision positioning system. Because omitting boundary condition, the method images adopted to predict distributions global and local magnetic field obtaining precise calculations. derivation flux density formulae are shown in this paper. By comparing distributions, it proves that could improve air-gap density. FEA curves coincident, at different position, demonstrates analytically predicted exact.

Most of superconducting motors use the coils as excitation which are located in rotor. But its cool system is complex and temperature lower than 60 K. A novel axial-radial flux HTS (high superconducting) motor presented with liquid nitrogen cool, armature winding stator coils, cover permanent magnets Its simple, easy to implement. electromagnetic parameters required ensure current can flow low voltage. Through prototype test copper instead winding, a rotor structure fit for presented.