Article Combined Simulation of a Micro Permanent Magnetic Linear Contactless Displacement Sensor (original) (raw)

Combined Simulation of a Micro Permanent Magnetic Linear Contactless Displacement Sensor

Sensors, 2010

The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO ® software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.

Micro displacement sensing system and its application to micro magnetic bearings

Device and Process Technologies for MEMS and Microelectronics II, 2001

In this paper we present a novel displacement sensing system where the sensing direction is in the plane of the planar sensor coils. Particular emphasis in this work is given to the design and micro fabrication of the sensor coils. Preliminary analysis and experiments have been carried out to determine the most suitable geometry and number of turns for the sensor coils. It has been found that the position of the sensor coils is extremely important as the location of the sensor coils relative to the target significantly affects the sensitivity of the resultant sensing system. Extensive experiments have been carried out using a number of different coil geometries with the same signal conditioner in each case. These experiments show that best sensitivity is achieved when the sensor coil is located so that the overlap area between the rotor and the sensor coil turns changes most rapidly with the rotor displacement. Following the preliminary analysis and experiments, new optimized sensor coils have been designed and micro fabricated using UV lithography and electroplating, as detailed in the paper. Performance testing of the resultant sensing system has been carried out and is reported in the paper. In addition, the displacement system has been applied to a micro magnetic bearing system for suspending a micro rotor.

System for inductive sensors study

2013

In this paper is proposed a method for testing inductive displacement sensors by performing a digital system allowing controlled movement, with a certain minimum precision, of a magnetic core of inductive sensors. The system also comes with a data acquisition system designed to measure and draw graphics the characteristics of the inductive displacement sensors analyzed. Key-words: inductive sensors, data acquisitions, system, displacement, coil, core

Mechanical Modeling and Sensitivity Evaluation of an Electrodynamic MEMS Microsensor

In this paper, we present the mechanical modeling of a MEMS electrodynamic microphone using finite element analysis. This new model aims to study the mechanical design of a microphone to predict its dynamic range performance. Two coaxial planar inductors, one external and the other is internal, are used in this microphone design. When the external inductor is flown by a current, it will produce a magnetic field within the internal suspended one located on the top of a suspended membrane above a micromachined cavity. In the present study, the membrane is attached around its edges, to avoid opening in the top membrane surface which leads usually to an acoustic short path in low frequencies that can affect the microphone performance. So, both membrane resonant frequency and displacement have been determined according to the used technology in IIT Bombay-India. The frequency was optimized around 1.6 KHz in the geometric mean of the acoustic band (2 0 Hz -20 k Hz ) and the harmo nic displa cemen t w as around 8µm for the main resonant frequency. Finally, the sensitivity was evaluated by coupling different transducer domains involved in the microsensor principle and by using the lumped element model of the microphone. The ultimate sensitivity was found around 0.1V/Pa, which is considered to be quite good compared to previously published sensitivities. However, the bandwidth was quite narrow for acting as a microphone.

A Methodology for the Simulation of MEMS Spiral Inductances used as Magnetic Sensors

COMSOL Conference, 2010

In this paper, a methodology to simulate the electric behavior of spiral inductances is presented and discussed. All the methodology is built with the Comsol software used with the Matlab scripting interface and then allows performing fully parameterized simulations. The program architecture is explained and is used to simulate two applications. The first calculates the voltage induced by an external AC magnetic field. The second is to detect the presence of moving metallic particles of micrometric dimensions; the program thus extracts the varying inductances values. The final goal of this approach is to manufacture sensors in MEMS technologies and co-integrate them with CMOS circuits.

Numerical and Experimental Investigation on Contactless Resonant Sensors

Procedia Chemistry, 2009

This paper reports numerical and experimental investigation on a BESOI-MEMS device. The implemented contactless actuation principle exploits Lorentz forces exerted on a conductive-non magnetic surface of the sensor, deriving from interaction between the eddy currents and the radial magnetic field, both generated by a sinusoidally driven external inductor. Both excitation and readout strategies are performed remotely via a magnetic strategy; moreover, the conceived sensor has been first numerically studied by using CoventorWare ™ 2008, then the device prototype has been fabricated and a preliminary experimental campaign has been performed to characterize the system in terms of variation of its resonance frequency.

Modelling and analysis of a magnetic microactuator

Sensors and Actuators A: Physical, 2000

This paper describes the operation of a magnetic microactuator. A prototype device consisting of a Nd-Fe-B permanent magnet, a silicon membrane and an electroplated copper coil is used to verify models and to predict the deflection of the magnetic microactuator. The analysis of this device involves the investigation of its electromagnetic and mechanical behaviour using analytical methods and finite Ž. element analysis FEA. A design procedure for a magnetic microactuator is also outlined. The prototype device was characterised and the measured results compared to the theoretical data. Results show that the deflection of the device may be predicted to an accuracy of 20%.

Modeling of High-Frequency Electromagnetic Effects on an Ironless Inductive Position Sensor

The ironless inductive position sensor (I2PS) is a five-coil air-cored structure that senses the variation of flux linkage between supply and sense coils and relates it to the linear position of a moving coil. In air-cored structures, the skin and proximity effect can bring substantial variations of the electrical resistance, leading to important deviations from the low-frequency functioning. In this paper, an analysis of the effect of high-frequency phenomena on the I2PS functioning is described. The key-element is the modeling of the resistance as a function of the frequency, which starts from the analytical resolution of Maxwell's equations in the coil's geometry. The analysis is validated by means of experimental measurements on custom sensor coils. The resulting model is integrated with the existing low-frequency analysis and represents a complete tool for the design of an I2PS sensor, framing its electromagnetic behavior.

Microfabricated Inductive Micropositioning Sensor for Measurement of a Linear Movement

IEEE Sensors Journal, 2006

An inductive device with a moving core will change its inductance as a function of the core position. By extending this principle to a microtransformer with multiple evenly spaced cores, a measurement system combining features of analog (variable reluctance) and incremental positioning may be devised. For detecting the direction of motion system (to know in which direction to count), an incremental length-measurement system not only requires one, but two output signals, which have to be offset by 90 •. This paper presents a microtransformer-based positioning system fulfilling these requirements. It presents the fabrication technology employed and discusses experimental test results.