In this contribution, a method will be presented to derive an envelope model for vibratory gyroscopes capturing the essential slow dynamics envelope of the system. Overview a tuning fork mems gyroscope is designed with a perforated proof mass. Simulations and measurements proving the feasibility of the proposed concepts. The core of the closedloop is to keep the vibration speed stable by adding driving force offset the damping force. Modelling of mems vibratory gyroscopes utilizing phase. In this paper, frequency measurement methods of resonant vibratory gyroscopes are studied. These gyroscopes use electrostatic comb drive to activate the device in x. Due to their wide applications in inertial navigation, automotive stability control and robots, mems gyroscopes have drawn tremendous attention of researchers in both academia and industry 1. An optimized analog drivemode controller for vibratory.
Model predictive control of mems vibratory gyroscope. Redundant information processing techniques comparison for. The most common mems gyroscope is the cvg which is a massspringdamper. The methodology will be exemplarily carried out for a capacitive gyroscope with electrostatic actuators and sensors. System identification of mems vibratory gyroscope sensor. Mems vibratory gyroscopes provides a solid foundation in the theory and. In microelectromechanical vibratory gyroscopes, feedback control is a common strategy in attempting to correct the imperfections. The closedloop with a single automatic gain control agc loop is chosen to maintain the vibration speed stable, and then the closedloop with agc is analyzed to obtain its transfer. Download it once and read it on your kindle device, pc, phones or tablets. Mems vibratory gyroscopes provides a solid foundation in the theory and fundamental operational principles of micromachined vibratory rate gyroscopes, and introduces structural designs that provide inherent robustness against structural and environmental variations. While vibrating ring gyroscopes and tuning fork gyroscopes were the first successful mems gyroscopes and are still the most widely produced, other successful mems gyroscopes have since been created. A mems gyroscope is a micromachined inertial device that can be used to measure the angular rate of rotation or the angle of orientation. Systematic control design method exemplarily carried out for capacitive gyros. Pdf modeling and simulation of the mems vibratory gyroscope.
The principle of drive closedloop for tuning fork comb mems vibratory gyroscope is analyzed. Highlights envelope modeling technique applied to vibratory mems gyroscopes. The sensing element in the bar type is formed by several vibrating objects similar to the bars of a tuning fork. In this paper, an analog circuit model for the drive mode of a twodegreeoffreedom mems vibratory gyroscope is presented.
Coriolis vibratory gyroscopes theory and design vladislav. Theory and design of micromechanical vibratory gyroscopes. In the first part, the dynamics of the vibratory gyroscope sensing element is. Modelbased control concepts for vibratory mems gyroscopes. Coriolis vibratory gyroscopes ebook by vladislav apostolyuk. However, a purely feedback control can be insufficient for compensation of all the errors, requiring post processing in the form of laser trimming to achieve higher levels of performance. A mathematical model for a singlemass vibratory gyroscope and some modes of its operations are considered and relations between measured values angle of rotation or angular rate and sensitive mass generalized coordinates are described. Us6046531a us09108,500 us10850098a us6046531a us 6046531 a us6046531 a us 6046531a us 10850098 a us10850098 a us 10850098a us 6046531 a us6046531 a us 6046531a authority us united states prior art keywords vibration bending leg vibrator base part prior art date 19970704 legal status the legal status is an assumption and is not a legal conclusion. This paper aims to put forward a detailed sensitivity analysis of an inplane mems gyroscope with respect to various performance criteria that are very critical for use of the sensor in different applications ranging from platform stabilization to micro uavs. First, the working principle and dynamic output characteristics of the resonant vibratory gyroscope are introduced, which provide a theoretical analysis base to analyze the dynamic frequency output characteristic of the resonant vibratory gyroscope. Mems vibratory gyroscope graduation project thesis 1 faculty of engineering ain shams university in partial fulfillment of the requirements for the degree bachelor of science in communication systems engineering submitted byabdel rahman elnaggar, ahmed magdy, ahmed m. Dynamics of micromechanical coriolis vibratory gyroscopes article pdf available in sensor letters 234.
Vibratory gyroscope article about vibratory gyroscope by. Feng and fan 10 presented an adaptive estimatorbased technique to estimate the angular motion by providing the coriolis force as the input to the adaptive estimator and to improve the bandwidth of. Microelectromechanical systems mems vibratory gyroscopes are among the most commercialized mems products. Active structural error suppression in mems vibratory rate. The disk is 5cm 2 inches across and because of its size its ideal for younger children. Designs that were used to produce micromechanical gyroscopes are shown in. Control of mems coriolis vibratory gyroscopes eeweb. Fab rication methods of mems technology have made possible to construct gyroscopes in very compact sizes.
An analog circuit model for drive mode of mems vibratory. Mems gyroscopes, or strictly speaking mems angular rate sensors, are used whenever rate of turn s sensing is required without a fixed point of reference. Dreyer department of mechanicalandmechatronic engineering, university ofstellenbosch, private bag x1,7602matieland,southafrica thesis. This article discusses the various control mechanisms for mems coriolis vibratory gyroscopes cvg, and how they can be applied with the commercial offtheshelf hf2li lockin amplifier.
Mems vibratory gyroscopes structural approaches to improve robustness cenk acar and andrei shkel isbn. One of these gyroscopes is the piezoelectric plate gyroscope which uses a pzt plate as its base. Evaluating error sources during mems gyroscope selection. Micromechanical vibratory gyroscopes or angular rate sensors have a large potential for different types of applications as primary information sensors for guidance, control and navigation systems. Mems vibratory gyroscopes is a must have book for engineers in both industry and academia who specialize in the design and manufacture of gyroscopes. Technically speaking, gyroscopes are instruments fo r measuring the rotation rate of a rigid element. They represent an important inertial technology because other gyroscopes such as solidstate gyroscopes, laser ring gyroscopes and fibre optic. To investigate the real behavior of the gyroscope sensor, the cubic stiffness coefficient is considered. The perforation enables the release of the proof mass during etching process in the fabrication. Read coriolis vibratory gyroscopes theory and design by vladislav apostolyuk available from rakuten kobo. Gyroscopes would be more reliable and less expensive if they had neither spinning wheels nor flotation fluids. System modeling of a mems vibratory gyroscope and integration to.
This separates gyros from any other means of measuring rotation, such as a tachometer or potentiometer. The proposed approach develops an online identifier scheme, by rewriting the dynamic model of mems gyroscope. Sensitivity analysis involves selecting key design parameters and critical performance criteria and studying the effect of variation. The resulting envelope model can be utilized for both transient and steady state simulations with the. With the aid of illustrations you will be shown the principles of gyroscopes including precession and nutation, where and how gyroscopes are used. A vibrating structure gyroscope, defined by the ieee as a coriolis vibratory gyroscope cvg, is a gyroscope that uses a vibrating structure to determine the rate of rotation. Silicon sensings mems gyros all use the same unique patented vsg resonating ring technology to sense rotation rate through a. Singledegreeoffreedom gyro sdfg wheel bearings must be stiff and isoelastic, and for both sdfgs and dynamically tuned gyros dtgs the bearings must be noiseless, as low friction as possible, and must start at low temperatures. Theory and design of micromechanical vibratory gyroscopes 175 oscillatory continuous discrete multiple single hrg ring tuning fork single mass beam gimballed wheel rotary dtg figure 2. This book provides the latest theoretical analysis and design methodologies of different types of coriolis vibratory gyroscopes cvg.
Thesis 1 mems vibratory gyroscope and readout circuit. Gyroscopes are used in various applications to sense either the angle turned through by a vehicle or structure displacement gyroscopes or, more commonly, its angular rate of turn about some defined axis rate gyroscopes. Posted saturday, september 16, 2017 this application note gives an overview of different control mechanisms for mems coriolis vibratory gyroscopes cvg and how they are implemented using the commercial offtheshelf hf2li lockin amplifier. Mems vibratory gyroscopes structural approaches to improve. To compare the all the gyroscopes on the website visit this page. This book was written as a response to a lack of publications offering easily understandable information on gyroscopes. A dynamical envelope model for vibratory gyroscopes. An optimized analog drivemode controller for vibratory mems gyroscopes burak eminoglua, said emre alperb, tayfun akina,b a a dept. Advantages of differential coriolis vibratory gyroscope of the new type with two measuring channels of angle rate with opposite signs that provides redundant. This is accomplished by an electronic feedback system which. Optimized startup strategy, quadrature compensation and force feedback control being discussed. In the first part, the dynamics of the vibratory gyroscope sensing element is developed, common microfabrication. Analysis and design of a 3rd order velocitycontrolled. A simplified model of vibratory gyros is shown in figure 1.
First, the operational principle and design issues are introduced. Selvakumar rajalakshmi engineering college, chennai 602105 india email. Mems vibratory gyroscopes, velocitycontrolled closedloop, 3rd order, linear model, optimization methodology. Structural approaches to improve robustness mems reference shelf cenk acar, andrei shkel on. Continuous tuning and calibration of vibratory gyroscopes vibrational excitation is periodically switched between orthogonal axes to derive calibration data. Fabrication defects and perturbations affect the behavior of a vibratory mems gyroscope sensor, which makes it difficult to measure the rotation angular rate. High grade coriolis vibratory gyroscopes for stabilisation control. There are bar and rotor types of vibratory gyroscope. Nasas jet propulsion laboratory, pasadena, california a method of control and operation of an inertial reference unit iru based on vibratory gyroscopes provides for. Some details for the forced oscillations mode used in. Modelling of mems vibratory gyroscopes utilizing phase detection a. In practical implementations of vibratory rate gyroscopes stabilization of the drivemode velocity is desired to reduce the effect of manufacturing tolerances and operational conditions on the scale factor of the sensor.
The proof mass used in the design enables the reduction of damping effect. A vibrating structure gyroscope, defined by the ieee as a coriolis vibratory gyroscope cvg, is a gyroscope that uses a vibrating structure to determine the rate. Control of mems coriolis vibratory gyroscopes page 2 theoretical background a gyroscope is an inertial device for measuring the angle of orientation or angular rate of rotation with respect to the inertial frame of reference. Although all vibratory mems gyroscopes rely on the rotationinduced coriolis force, the operating modes of the two technologies are different. The paper deals with the principles of singleaxis vibratory gyroscope operation. Structural approaches to improve robustness mems reference shelf acar, cenk, shkel, andrei on. This model is implemented on a printed circuit board by analog integrated circuits. A unique balance between theory and practical design issues. Mems vibratory gyroscopes structural approaches to. Continuous tuning and calibration of vibratory gyroscopes. This paper presents a novel adaptive approach that can identify, in an online fashion, angular rate and other system parameters. Theory and design kindle edition by apostolyuk, vladislav. Pdf dynamics of micromechanical coriolis vibratory. Vibratory gyroscope an instrument for determining the angular velocity of an object.
In a tuning fork device, there is a transfer of energy between two flexural modes of a proofmass held in place via suspension springs. Acar et al environmentally robust mems vibratory gyroscopes for automotive applications 1897 to meet strict speci. Sensitivity analysis of an inplane mems vibratory gyroscope. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Structural approaches to improve robustness mems reference shelf.
This book aims to fill the gap between dictionary definitions and the all too often highly mathematical books on gyroscopes. Us6747393b2 us10177,863 us17786302a us6747393b2 us 6747393 b2 us6747393 b2 us 6747393b2 us 17786302 a us17786302 a us 17786302a us 6747393 b2 us6747393 b2 us 6747393b2 authority. Use features like bookmarks, note taking and highlighting while reading coriolis vibratory gyroscopes. The sensors are used in a variety of roles such as. Mscengmech march2008 this thesis aims to contribute to themodellingand analysisofmems gyroscope technologies. Pullcord and strand are enclosed along with a detailed explanation and instructions. In the first part, the dynamics of the vibratory gyroscope sensing element is developed, common microfabrication processes and. Us6046531a vibrator, vibratory gyroscope, and linear. This proposed circuit can be a suitable test bench for designers of. Leading manufacturer of highperformance inertial sensors, including tactical grade, coriolis vibratory gyroscopes and navigation grade, quartz servo. A vibrating structure gyroscope functions much like the halteres of flies insects in the order diptera the underlying physical principle is that a vibrating object tends to continue vibrating in the same plane even. Thesis 1 mems vibratory gyroscope and readout circuit 1. Together, the chapters analyze different types of sensitive element designs and their kinematics, derivation of motion equations, analysis of sensitive elements dynamics in modulated and demodulated signals, calculation and optimization of main performance.
Then, cmoscompatible mems gyroscopes with different designs are re. Mems gyroscope technology provides cost effective method for improving directional estimation and overall accuracy in the navigation systems. Frequency measurement study of resonant vibratory gyroscopes. Most of the mems gyroscopes are of vibratory kind gyroscopes, i. Design and analysis of a mems comb vibratory gyroscope. Kugi, modelbased control concepts for vibratory mems gyroscopes, mechatronics,22,3,241250,2012.
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