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Статті в журналах з теми "Angular rate measurement mode"
1
Chen, Feng, Guangjun He, and Qifang He. "A Composite Guidance Law for Suppressing Measurement Noise of LOS Angular Rate." Mathematical Problems in Engineering 2019 (January 6, 2019): 1–10. http://dx.doi.org/10.1155/2019/7453602.
Повний текст джерелаАнотація:
To effectively intercept a low-altitude target in clutter background, a nonsingular fast terminal sliding mode guidance law is designed. The designed guidance law can fully exploit the fast convergence characteristics of linear sliding mode control and the finite-time-convergent characteristics of terminal sliding mode control to ensure that the line-of-sight (LOS) angle converges to a desired angle in a limited time at a faster rate. Utilizing the smooth switching characteristics of the hyperbolic tangent function similar to the saturation function, a finite-time-convergent differentiator is designed. Meanwhile, a new finite-time-convergent disturbance observer designed on the tracking differentiator can effectively track the ideal LOS angular rate, suppress the measurement noise, and make a smooth estimation of the target maneuvering acceleration in clutter background. Combining the estimated value of the disturbance observer, the sign function with switch coefficient is introduced to design a composite nonsingular fast terminal sliding mode guidance law. The simulation results show that the composite guidance law can not only effectively suppress the measurement noise of the LOS angular rate and improve the accuracy of low-altitude target intercepting, but also greatly reduce the energy consumption in the interception process.
2
Yang, Zhaohua, Dan Li, and Yuzhe Sun. "Analysis of Kerr Noise in Angular-Rate Sensing Based on Mode Splitting in a Whispering-Gallery-Mode Microresonator." Micromachines 10, no. 2 (February 23, 2019): 150. http://dx.doi.org/10.3390/mi10020150.
Повний текст джерелаАнотація:
Whispering-gallery-mode (WGM) microresonators have shown their potential in high-precision gyroscopes because of their small volume and high-quality factors. However, Kerr noise can always be the limit of accuracy. Angular-rate sensing based on mode splitting treats backscattering as a measured signal, which can induce mode splitting, while it is considered as a main source of noise in conventional resonator optical gyroscopes. Meanwhile, mode splitting also provides superior noise suppression owing to its self-reference scheme. Kerr noise in this scheme has not been defined and solved yet. Here, the mechanism of the Kerr noise in the measurement is analyzed and the mathematical expressions are derived, indicating the relationship between the Kerr noise and the output of the system. The influence caused by Kerr noise on the output is simulated and discussed. Simulations show that the deviation of the splitting caused by Kerr noise is 1.913 × 10−5 Hz at an angular rate of 5 × 106 °/s and the corresponding deviation of the angular rate is 9.26 × 10−9 °/s. It has been proven that angular-rate sensing based on mode splitting offers good suppression of Kerr noise.
3
Jin, Jaehyun, and Dongguk Kim. "Force-To-Rebalance Mode of a Resonator Gyro and Angular Rate Measurement Tests." Journal of Institute of Control, Robotics and Systems 20, no. 5 (May 1, 2014): 563–69. http://dx.doi.org/10.5302/j.icros.2014.13.1983.
Повний текст джерела
4
Mohammadi, Zohreh, and Hassan Salarieh. "Effects of linear acceleration in a harmonically excited proof mass MEMS rate gyroscope." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 19 (November 19, 2017): 3551–63. http://dx.doi.org/10.1177/0954406217739645.
Повний текст джерелаАнотація:
MEMS rate gyroscopes are prone to different errors because of environmental conditions and manufacturing errors. These errors can result to mismatch between the fabricated gyros and the designed ones. Different environmental conditions and disturbances can change the parameters and specifications of a gyro, and its sensitivity may deteriorate, since the parameters are different from the optimal ones. External linear acceleration is one of the main environmental disturbances that may change the behavior of an MEMS rate gyro that its effect on the accuracy of an MEMS proof mass gyroscope is found here. This is done by finding the equations of motion of gyroscope in presence of acceleration and solving the equations analytically and numerically and then surveying changes of calibration diagram of a typically designed gyro after addition of acceleration to the equations. Also, the error in angular velocity sensing will be found. It is seen that linear external acceleration can make a constant bias in the drive and sense mode responses in different angular velocities. But, change of sense mode amplitude in different external linear accelerations is very low. Angular velocity can be calibrated according to the sense mode amplitude or the maximum value of the output. The error percent of angular velocity measurement is very different in these two methods.
5
Mi, Jing, Jie Li, Xi Zhang, Kaiqiang Feng, Chenjun Hu, Xiaokai Wei, and Xiaoqiao Yuan. "Roll Angular Rate Measurement for High Spinning Projectiles Based on Redundant Gyroscope System." Micromachines 11, no. 10 (October 16, 2020): 940. http://dx.doi.org/10.3390/mi11100940.
Повний текст джерелаАнотація:
Precision-guided projectiles, which can significantly improve the accuracy and efficiency of fire strikes, are on the rise in current military engagements. The accurate measurement of roll angular rate is critical to guide a gun-launched projectile. However, Micro-Electro-Mechanical System (MEMS) gyroscope with low cost and large range cannot meet the requirement of high precision roll angular rate measurement due to the limitation by the current technology level. Aiming at the problem, the optimization-based angular rate estimation (OBARS) method specific for projectiles is proposed in this study. First, the output angular rate model of redundant gyroscope system based on the autoregressive integrated moving average (ARIMA) model is established, and then the conventional random error model is improved with the ARIMA model. After that, a Sage-Husa Adaptive Kalman Filter (SHAKF) algorithm that can suppress the time-varying process and measurement noise under the flight condition of the high dynamic of the projectile is designed for the fusion of dynamic data. Finally, simulations and experiments have been carried out to validate the performance of the method. The results demonstrate the proposed method can effectively improve the angular rate accuracy more than the related traditional methods for high spinning projectiles.
6
Zhao, Hui, Zhong Su, Fuchao Liu, Chao Li, Qing Li, and Ning Liu. "Extraction and Filter Algorithm of Roll Angular Rate for High Spinning Projectiles." Mathematical Problems in Engineering 2019 (March 26, 2019): 1–15. http://dx.doi.org/10.1155/2019/3181727.
Повний текст джерелаАнотація:
The accurate measurement of roll angular rate for high spinning projectile has long been a challenging problem. Aiming to obtain the accurate roll angular rate of high spinning projectile, a novel extraction and filter algorithm, BSCZT-KF, is proposed in this paper. Firstly, a compound angular motion model of high spinning projectile is established. According to the model, we translate the roll angular rate measurement problem into a frequency estimation problem. Then the improved CZT algorithm, BSCZT, was employed to realize an accurate estimation of the narrowband signal frequency. Combined with the peak detection method, the BSCZT-KF algorithm is presented to further enhance the frequency estimation accuracy and the real-time performance. Finally, two sets of actual flight tests were conducted to verify the effectiveness and accuracy of the algorithm. The test results show that the average error of estimated roll angular rate is about 0.095% of the maximum of roll angular rate. Compared with the existing methods, the BSCZT-KF has the highest frequency estimation accuracy for narrowband signal.
7
Duan, Meijun, Di Zhou, and Dalin Cheng. "Extended state observer-based finite-time guidance laws on account of thruster dynamics." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 12 (February 12, 2019): 4583–97. http://dx.doi.org/10.1177/0954410019827175.
Повний текст джерелаАнотація:
Guidance laws are designed for a near space interceptor with line-of-sight angle as input and on–off type thrust as output. The dynamics of thruster is viewed as a first-order lag with on–off working style and is integrated with the target–interceptor engagement dynamics to design bang-bang type sliding mode guidance laws. An extended state observer is designed to estimate the line-of-sight angular rate and the acceleration of target with the line-of-sight angle as a measurement. It is rigorously proved that the states of guidance system converge to a neighborhood of sliding mode in finite time and the line-of-sight angular rate converges to a neighborhood of the origin along the sliding mode in finite time under the designed guidance laws. Furthermore, in order to reduce the switching frequency of thruster, a sliding mode guidance law with hysteresis-band according to the sufficient condition for finite time convergence is proposed. Then, it is integrated with the bang-bang type sliding mode guidance law to yield a composite guidance law. Simulation results show that the extended state observer can effectively estimate the line-of-sight angular rate and the target acceleration, and the proposed sliding mode guidance laws have better performance than typical proportional guidance law.
8
Zhang, Xiao Ming, Dai Di Zhao, Jian Yu Shang, Xing Cui, and Jun Liu. "The Triaxial Angular Rate Measurement System Based on Two MEMS Accelerometers Used for Rotating Carrier." Key Engineering Materials 609-610 (April 2014): 1219–25. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.1219.
Повний текст джерелаАнотація:
Considering that the MEMS Gyroscope used in rotating carrier has the problems of small range and low measurement accuracy, the tri-axial angular rate measurement system based on two MEMS accelerometers used for rotating carrier was presented in this paper. The system has the advantages of large measurement range, anti-high overload, simple structure, small volume and low price. From the principle of the tri-axial angular rate measurement system, the mathematical model of the system was established and the mechanics model of the system was discussed. The different processing method of the output signal in each condition was summarized based on the mechanics model. Finally, the semi-physical simulation experiment was done to verify these theories. The experimental results show that the system scheme is feasible and has obvious advantages in the range and measurement accuracy.
9
Liu, Zengjun, Lei Wang, Kui Li, Jingxuan Ban, and Meng Wang. "A Calibration Method for the Errors of Ring Laser Gyro in Rate-Biased Mode." Sensors 19, no. 21 (November 1, 2019): 4754. http://dx.doi.org/10.3390/s19214754.
Повний текст джерелаАнотація:
Ring laser gyro (RLG) can work in mechanically dithered mode or rate-biased mode according to the working state of the inertial navigation system (INS). It can change from one mode to the other by receiving outer instructions. To evaluate the performance of RLG in rate-biased mode, an inertial measurement unit (IMU) based on RLG is installed on a dual-axis turntable, the turntable offers a constant angular velocity to the RLGs, in that way RLG can work in the rate-biased mode. A calibration method is proposed to calibrate the scale factor error, misalignments and constant bias of RLG in rate-biased mode, experiment results show that the differences of scale factor of the three gyros in two modes are 9 ppm, 7 ppm and 3.5 ppm, the constant biases of the three RLGs in rate-biased mode are also different from that in mechanically dithered mode with the difference of 0.017°/h, 0.011°/h and 0.020°/h, the input axis misalignment angle of RLGs in different modes also changed. What is more, a calculation method of angle random walk (ARW) of RLG in rate-biased mode is also presented. Experimental results show that the ARW of the RLG in rate-biased mode is about one third of that in mechanically dithered.
10
Jiang, Shang, Dongyan Sun, Shiyan Sun, Xinhui Men, and Chang Cai. "Distributed fuzzy adaptive cooperative strategy considering communication delay and multiple constraints." AIP Advances 12, no. 4 (April 1, 2022): 045025. http://dx.doi.org/10.1063/5.0090084.
Повний текст джерелаАнотація:
In order to enhance penetration and damage ability of targets under multi-constraint conditions, a distributed fuzzy adaptive cooperative strategy was proposed to networked guided projectiles for operation considering communication delay. Aiming at the measurement limitation of the line of sight (LOS) angular rate, the extended state observer was designed to estimate the LOS angular rate and disturbance accurately and quickly. For overcoming communication delay, based on cooperative consistency theory and integral sliding mode control, the distributed control quantity in the LOS direction was designed to converge hit time in limited time. In the normal direction of LOS, the nonsingular terminal sliding mode with an exponential adaptive reaching law was designed to ensure rapid convergence of the LOS angular rate using remaining flight time. In order to weaken the negative influence of sliding mode high-frequency chattering on the system, the fuzzy adaptive controller with a universal approximation was introduced. Finally, by constructing the Krasovskii function and Lyapunov stability theory, it was proved that the whole system was uniformly ultimately bounded. Simulation results indicated that the strategy possessed better cooperative performance against the maneuvering target and made networked guided projectiles adapt to communication delay and multiple constraints better, compared with the existing methods.
Дисертації з теми "Angular rate measurement mode"
1
Петренко, Олексій Володимирович. "Удосконалення методів підвищення точності вібраційного гіроскопа з металевим циліндричним резонатором". Thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/36992.
Повний текст джерелаАнотація:
Робота виконана на кафедрі аерокосмічних систем управління Національного авіаційного університету Міністерства освіти і науки України та у Публічному акціонерному товаристві «Науково-виробниче об’єднання «Київський завод автоматики».Дисертаційна робота присвячена науковому обґрунтуванню та розробці алгоритмів компенсації внутрішніх похибок та зовнішніх збурень у Коріолісовому вібраційному гіроскопі, а також удосконаленню його складових частин (резонатора, чутливого елементу). Автором розроблено методику та обладнання для робочого місця безелектродного вимірювання динамічних параметрів металевого резонатора після його виготовлення, розроблено конструкцію приладдя для приклеювання п’єзоелектродів до резонатора нової конструкції, методику та обладнання робочого місця для балансування мас. Розроблено та відпрацьовано на експериментальному зразку КВГ методики температурної корекції фаз сигналів квадратури та кутової швидкості, багатопараметричної корекції дрейфу нуля і масштабного коефіцієнту, що призводить до збільшення точності виміру кутової швидкості в умовах дії температурних градієнтів.
In the thesis the following new scientific results are obtained: 1. For the first time, a multi-parameter method of CVG scale factor correction is developed and implemented, which can be used during the CVG operation in the rate and in the differential modes. Ukraine patent have been obtained for this method. 2. Scientifically grounded analysis of a new design of a cylindrical resonator with holes on the walls of a cylinder having higher vibration resistance was first developed and carried out. 3. The multiparameter bias correction algorithm has been developed and implemented, which has advantages over the existing ones by accuracy. 4. For the first time experimental researches were carried out on a manufactured experimental sample of CVG with developed metal cylindrical resonator made of elenvar elloy, which showed high accuracy scale factor and bias drift correction under the action of temperature gradient, as well as high shockvibration resistance of the sample. The practical significance of thesis results are: − comparison of two designs of metallic cylindrical resonators with holes on the bottom and on the wall of the cylinder and by calculations and computer simulation the advantages of the second design over the first one in the part of shock resistance have been substantiated; − аn analysis of the different geometries of the holes has been made. Their influence on the resonant oscillation frequencies of a cylindrical resonator is revealed. Recommendations for the geometry of the resonator and its elements have been developed; − improved design of the base on which the newly designed resonator with holes on the wall of the cylinder is installed; − the choice of electrodes used for oscillation excitation and measurement of the signals is experimentally substantiated; − the technique and equipment for workplace electrodeless measurement of metallic resonator dynamic parameters after its manufacture have been developed; − the influence of frequency mismatch, wave angle and positioning errors of the electrodes on the CVG bias and scale coefficient have been evaluated; − a new accessory design has been developed to attach the electrodes to the new resonator design; − the technique and equipment of the workplace for balancing the mass of the resonator on the fourth harmonic of the unbalance to reduce its frequency mismatch have been developed. The technique was tested in the manufactured ample of CVG; − the technique of measuring the angles of non-orthogonality of the sensitive axis to its mounting surface has been developed and implemented in the experimental sample of CVG; − the use of CVG to improve the accuracy of armament stabilization was analyzed; − improved CVG standing wave control algorithm block diagram, which provides a fast start of the gyroscope when it is turned on at any temperature in the range of operating temperatures; − the techniques for temperature correction of quadrature and angular rate phases, multiparameter correction of CVG bias and scale factor have been developed and tested on experimental sample of CVG, which leads to an increase in the accuracy of measuring angular rate under temperature gradients; − the experimental results showed that the CVG with a metallic resonator is resistant to multiple shocks with amplitude 100 g and its bias is slightly dependent on the shock amplitude and does not exceed 5×10−3 deg/s. The bias sensitivity to vibration perturbations is 2.5×10−3 deg/s/g.
Диссертация посвящена научному обоснованию и разработке алгоритмов компенсации внутренних погрешностей и внешних возмущений в Кориолисового вибрационном гироскопе, а также совершенствованию его составных частей (резонатора, чувствительного элемента). Автором разработана методика и оборудование для рабочего места безэлектродного измерения динамических параметров металлического резонатора после его изготовления, разработана конструкция приспособления для приклеивания пьезоэлектродов к резонатору новой конструкции, методику и оборудование рабочего места для балансировки масс резонатора. Разработано и отработано на экспериментальном образце КВГ методики температурной коррекции фаз сигналов квадратуры и угловой скорости, многопараметрической коррекции дрейфа нуля и масштабного коэффициента, что приводит к увеличению точности измерения угловой скорости в условиях действия температурных градиентов.
2
Alper, Said Emre. "Mems Gyroscopes For Tactical-grade Inertial Measurement Applications." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606483/index.pdf.
Повний текст джерелаАнотація:
This thesis reports the development of high-performance symmetric and decoupled micromachined gyroscopes for tactical-grade inertial measurement applications. The symmetric structure allows easy matching of the resonance frequencies of the drive and sense modes of the gyroscopes for achieving high angular rate sensitivitywhile the decoupled drive and sense modes minimizes mechanical cross-coupling for low-noise and stable operation. Three different and new symmetric and decoupled gyroscope structures with unique features are presented. These structures are fabricated in four different micromachining processes: nickel electroforming (NE), dissolved-wafer silicon micromachining (DWSM), silicon-on-insulator (SOI) micromachining, and silicon-on-glass (SOG) micromachining. The fabricated gyroscopes have capacitive gaps from 1.5µ
m to 5.5µ
m and structural layer thicknesses from 12µ
m to 100µ
m, yielding aspect ratios up to 20 depending on the fabrication process. The size of fabricated gyroscope chips varies from 1x1mm2 up to 4.2x4.6mm2. Fabricated gyroscopes are hybrid-connected to a designed capacitive interface circuit, fabricated in a standard 0.6µ
m CMOS process. They have resonance frequencies as small as 2kHz and as large as 40kHz
sense-mode resonance frequencies can be electrostatically tuned to the drive-mode frequency by DC voltages less than 16V. The quality factors reach to 500 at atmospheric pressure and exceed 10,000 for the silicon gyroscopes at vacuum. The parasitic capacitance of the gyroscopes on glass substrates is measured to be as small as 120fF. The gyroscope and interface assemblies are then combined with electronic control and feedback circuits constructed with off-the-shelf IC components to perform angular rate measurements. Measured angular rate sensitivities are in the range from 12µ
V/(deg/sec) to 180µ
V/(deg/sec), at atmospheric pressure. The SOI gyroscope demonstrates the best performance at atmospheric pressure, with noise equivalent rate (NER) of 0.025(deg/sec)/Hz1/2, whereas the remaining gyroscopes has an NER better than 0.1(deg/sec)/Hz1/2, limited by either the small sensor size or by small quality factors. Gyroscopes have scale-factor nonlinearities better than 1.1% with the best value of 0.06%, and their bias drifts are dominated by the phase errors in the demodulation electronics and are over 1deg/sec. The characterization of the SOI and SOG gyroscopes at below 50mTorr vacuum ambient yield angular rate sensitivities as high as 1.6mV/(deg/sec) and 0.9mV/(deg/sec), respectively. The NER values of these gyroscopes at vacuum are smaller than 50(deg/hr)/Hz1/2 and 36(deg/hr)/Hz1/2, respectively, being close to the tactical-grade application limits. Gyroscope structures are expected to provide a performance better than 10 deg/hr in a practical measurement bandwidth such as 50Hz, provided that capacitive gaps are minimized while preserving the aspect ratio, and the demodulation electronics are improved.
3
Alharbi, Abdulmajeed A. "Investigating Survey Response Rates and Analytic Choice of Survey Results fromUniversity Faculty in Saudi Arabia." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1585051418774214.
Повний текст джерела
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Kok, Wing Hang (Ronald). "Development of a wireless MEMS inertial system for health monitoring of structures." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-11244-122741/.
Повний текст джерелаАнотація:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: angular rate; cantilever; wireless; RF; microcontroller; tilt and rotation; health monitoring; inertial sensors; MEMS. Includes bibliographical references (p. 139-145).
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Burnie, Marc. "MODAL ANALYSIS OF MEMS GYROSCOPIC SENSORS." Thesis, 2010. http://hdl.handle.net/1974/5701.
Повний текст джерелаАнотація:
Microgyroscopes find popular applications in modern life, such as, vehicle navigation, inertial positioning, human body motion monitoring, etc. In this study, three unique MEMS gyroscopic sensors were investigated using experimental methods and finite element analysis (FEA) modelling, particularly their modal behaviour. The analytical, simulated and experimental results were compared and the discrepancy between resonant frequencies of the significant mode shapes was discussed.
Three microfabricated gyroscopes were investigated: a thermally-actuated in-plane gyroscope, an electrostatically-actuated in-plane gyroscope and an electrostatically-actuated out-of-plane gyroscope. Numerical finite element modal analysis for these three gyroscopes was conducted using COMSOL Multiphysics. The experimental testing was conducted using a microsystem analyzer (MSA-400 PolyTec) with an integrated laser vibrometer.
The simulation models predicted that the frequencies for driving and sensing modes were 4.948kHz and 5.459kHz for a thermally-actuated gyroscope, which agreed well with experimentally determined results of 5.98kHz and 6.0kHz respectively. The power requirements of a thermally-actuated gyroscope were 363.39mW to elicit a maximum peak-to-peak displacement of 4.2μm during dynamic operation. Similarly, the simulated frequencies for the driving and sensing modes were 1.170kHz and 1.644kHz for an electrostatically-actuated in-plane gyroscope, which corresponded to experimentally determined resonant frequencies 1.6kHz and 1.9kHz.
Simulation for the electrostatically-actuated out-of-plane gyroscope was conducted and the frequencies for the driving and sensing modes were found to be 2.159kHz and 3.298kHz. Due to some fabrication defects, the experimental testing for this microgyroscope was not successful. Some recommendations to improve the design were provided for the future work.Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-06-02 22:00:52.994
6
Juang, Kai-Tsahn, and 莊鎧燦. "The Evaluation of Mode III Strain Energy Release Rate and Shear Moduli Measurement in Thick Composite Laminates." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/89643193250743559391.
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Pal, Madhumita. "Accurate and Efficient Algorithms for Star Sensor Based Micro-Satellite Attitude and Attitude Rate Estimation." Thesis, 2013. http://etd.iisc.ernet.in/2005/3428.
Повний текст джерелаАнотація:
This dissertation addresses novel techniques in determining gyroless micro-satellite attitude and attitude rate. The main objective of this thesis is to explore the possibility of using commercially available low cost micro-light star sensor as a stand-alone sensor for micro-satellite attitude as well as attitude rate determination. The objective is achieved by developing accurate and computationally efficient algorithms for the realization of onboard operation of a low fidelity star sensor. All the algorithms developed here are tested with the measurement noise presented in the catalog of the sensor array STAR-1000.
A novel accurate second order sliding mode observer (SOSMO) is designed for discrete time uncertain linear multi-output system. Our design procedure is effective for both matched and unmatched bounded uncertain ties and/or disturbances. The bound on uncertainties and/or disturbances is assumed to be unknown. This problem is addressed in this work using the second order multiple sliding modes approach. Second order sliding manifold and corresponding sliding condition for discrete time system is defined similar on the lines of continuous counterpart. Our design is not restricted to a particular class of uncertain (matched) discrete time system. Moreover, it can handle multiple outputs unlike single out-put systems. The observer design is achieved by driving the state observation error and its first order finite difference to the vicinity of the equilibrium point (0,0) in a finite steps and maintaining them in the neighborhood thereafter. The estimation synthesis is based on Quasi Sliding Mode (QSM) design.
The problem of designing sliding mode observer for a linear system subjected to unknown inputs requires observer matching condition. This condition is needed to ensure that the state estimation error is a asymptotically stable and is independent of the unknown input during the sliding motion. In the absence of a matching condition, asymptotic stability of the reduced order error dynamics on the sliding surface is not guaranteed. However, unknown bounded inputs guarantee bounded error on state estimation. The QSM design guarantees an ultimate error bound by incorporating Boundary Layer (BL) in its design procedure.
The observer achieves one order of magnitude improvement in estimation accuracy than the conventional sliding mode observer (SMO) design for an unknown input. The observer estimation errors, satisfying the given stability conditions, converge to an ultimate finite bound (with in the specified BL) of O(T2), where T Is the sampling period. A relation between sliding mode gain and boundary layer is established for the existence of second order discrete sliding motion. The robustness of the proposed observer with respect to measurement noise is also analyzed. The design algorithm is very simple to apply and is implemented for two examples with different classes of disturbances (matched and unmatched) to show the effectiveness of the design. Simulation results show the robustness with respect to the measurement noise for SOSMO.
Second order sliding mode observer gain can be calculated off-line and the same gain can work for large band of disturbance as long as the disturbance acting on the continuous time system is bounded and smooth. The SOSMO is simpler to implement on board compared to the other traditional nonlinear filters like Pseudo-Linear-Kalman-filter(PLKF); Extended Kalman Filter(EKF). Moreover, SMO possesses an automatic adaptation property same as optimal state estimator(like Kalman filter) with respect to the intensity of the measurement noise. The SMO rejects the noisy measurements automatically, in response to the increased noise intensity. The dynamic performance of the observer on the sliding surface can be altered and no knowledge of noise statistics is required. It is shown that the SOSMO performs more accurately than the PLKF in application to micro-satellite angular rate estimation since PLKF is not an optimal filter.
A new method for estimation of satellite angular rates through derivative approach is proposed. The method is based on optic flow of star image patterns formed on a star sensor. The satellite angular rates are derived directly from the 2D-coordinates of star images. Our algorithm is computationally efficient and requires less memory allocation compared to the existing vector derivative approaches, where there is also no need for star identification. The angular rates are computed using least square solution method, based on the measurement equation obtained by optic flow of star images. These estimates are then fed into discrete time second order sliding mode observer (SOSMO). The performance of angular rate estimation by SOSMO is compared with the discrete time First order SMO and PLKF. The SOSMO gives the best estimates as compared to the other two schemes in estimating micro-satellite angular rates in all three axes. The improvement in accuracy is one order of magnitude (around1.7984 x 10−5 rad/ sec,8.9987 x 10−6 rad/ sec and1.4222 x 10−5 rad/ sec in three body axes respectively) in terms of standard deviation in steady state estimation error.
A new method and algorithm is presented to determine star camera parameters along with satellite attitude with high precision even if these parameters change during long on-orbit operation. Star camera parameters and attitude need to be determined independent of each other as they both can change. An efficient, closed form solution method is developed to estimate star camera parameters (like focal length, principal point offset), lens distortions (like radial distortion) and attitude. The method is based on a two step procedure. In the first step, all parameters (except lens distortion) are estimated using a distortion free camera model. In the second step, lens distortion coefficient is estimated by linear least squares (LS) method. Here the derived camera parameters in first step are used in the camera model that incorporates distortion. However, this method requires identification of observed stars with the catalogue stars. But, on-orbit star identification is difficult as it utilizes the values of camera calibrating parameters that can change in orbit(detector and optical element alignment get change in orbit due to solar pressure or sudden temperature change) from the ground calibrated value. This difficulty is overcome by employing a camera self-calibration technique which only requires four observed stars in three consecutive image frames. Star camera parameters along with lens (radial and decentering) distortion coefficients are determined by camera self calibration technique. Finally Kalman filter is used to refine the estimated data obtained from the LS based method to improve the level of accuracy.
We consider the true values of camera parameters as (u0,v0) = (512.75,511.25) pixel, f = 50.5mm; The ground calibrated values of those parameters are (u0,v0) =( 512,512) pixel, f = 50mm; Worst case radial distortion coefficient affecting the star camera lens is considered to be k1 =5 x 10−3 .Our proposed method of attitude determination achieves accuracy of the order of magnitude around 6.2288 x 10−5 rad,3.3712 x 10−5 radand5.8205 x
10−5 rad in attitude angles φ,θ and ψ. Attitude estimation by existing methods in the literature diverges from the true value since they utilize the ground calibrated values of camera parameters instead of true values.
To summarize, we developed a formal theory of discrete time Second Order Sliding Mode Observer for uncertain multi-output system. Our methods achieve the desired accuracy while estimating satellite attitude and attitude rate using low fidelity star sensor data. Our methods require lower on-board processing requirement and less memory allocation; thus are suitable for micro-satellite applications. Thus, the objective of using low fidelity star sensor as stand-alone sensor in micro-satellite application is achieved.
Частини книг з теми "Angular rate measurement mode"
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Schiefer, Christoph, Thomas Kraus, Elke Ochsmann, Ingo Hermanns, and Rolf Ellegast. "3D Human Motion Capturing Based Only on Acceleration and Angular Rate Measurement for Low Extremities." In Digital Human Modeling, 195–203. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21799-9_22.
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Karadimas, Petros. "Stochastic Modeling of Narrowband Fading Channels with Three Dimensional Diffuse Scattering." In Handbook of Research on Heterogeneous Next Generation Networking, 361–81. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-108-7.ch016.
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This chapter studies a composite stochastic model, in which the diffuse component arises from three dimensional (3-D) multipath scattering. That case occurs especially in dense scattering environments, in which the tall obstacles cause arrival of multipath power in the elevation plane, besides that arriving in the azimuth one. Also the multipath components are assumed to arrive at the mobile receiver in specific angular sectors at the azimuth receiver’s plane. The last is physically justified by multipath power blocking due to the channel obstacles (shadow fading), or/and lack of scattering objects at specific angular directions, or/and directional antennas utilization. An extended Suzuki model, where the Rician process for the diffuse scattering component is multiplied by a lognormal one, is considered as an appropriate composite model. The most important metrics of the model are presented, according to its assumptions. More specifically, from the closed form autocorrelation function, the Doppler power spectral density (PSD) of the diffuse component can be analytically derived. Afterwards exact solutions for the envelope and phase probability density functions (PDF’s) are presented. Exact solutions are also derived for the second order statistics, i.e. the level crossing rate (LCR) and the average duration of fades (ADF’s). An efficient deterministic simulation scheme will be presented, which implements the analytical model on a digital computer. Finally a curve fitting of the LCR to real world data, drawn from channel measurements, will demonstrate the flexibility and usefulness of the extended Suzuki model.
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Lighton, John R. B. "Flow-through Respirometry: Excurrent Flow Measurement." In Measuring Metabolic Rates, 116–23. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198830399.003.0011.
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This chapter describes the setup, plumbing, and equations for implementing a respirometry system wherein the flow rate of the air leaving the animal chamber is known. Such systems are usually referred to as pull systems, because the air is usually pulled from a chamber or mask at a known rate, and the concentrations of incurrent and excurrent gases are alternately measured. Such systems are often the only practical way of measuring the metabolic rates of large animals. Setups and equations for oxygen-only, carbon dioxide-only, and combined oxygen and carbon dioxide systems are described. Methods for creating multiple-animal pull mode respirometry systems, for compensating flow rate, and for the automatic baselining (that is to say, measuring incurrent gas concentrations) of respirometry systems are discussed.
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Lighton, John R. B. "Flow-through Respirometry: Incurrent Flow Measurement." In Measuring Metabolic Rates, 101–15. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198830399.003.0010.
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This chapter describes the setup, plumbing, and equations required for applying a respirometry system wherein the flow rate of the air entering the animal chamber is known. Such systems are usually referred to as push systems, because the air is usually pushed into a sealed respirometer chamber at a known rate, and the concentrations of incurrent and excurrent gases are alternately measured. Setups and equations for oxygen-only, carbon dioxide-only, and combined oxygen and carbon dioxide systems are described. Methods for creating multiple-animal push mode respirometry systems and for the automatic baselining (that is to say, measuring incurrent gas concentrations) of respirometry systems are also discussed.
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Kumar, Arun, Padmini Sharma, and Mukesh Kumar Chandrakar. "Discriminating Significant Morphological Attributes of Photoplethysmograph Signal for Cuffless Blood Pressure Measurement." In Advances in Medical Technologies and Clinical Practice, 269–81. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-9831-3.ch013.
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Photoplethysmograph signal carries very useful cardiac information such heart rate, oxygen saturation level, blood pressure, and diabetic condition. Blood pressure is one such cardiac information that can be estimated by extracting features of PPG signal. Cuff-less blood pressure measurement using photoplethysmograph (PPG) signal is one of non-invasive methods. It allows continuous monitoring of blood pressure in simple, rapid, and low-cost mode. This chapter segregates PPG features and re-investigates their effectiveness in terms of BP measurement. Machine learning algorithm based on K-nearest neighbour is applied for classification of samples. MIMIC II multi-parameter database of ECG and finger PPG is applied on the KNN classifiers. Classification accuracy comes to 92%, and correlation between predicted and observed SBP and DSB are 0.89 and 0.85, respectively.
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Johann, Felix, David Becker, Matthias Becker, and E. Sinem Ince. "Multi-Scenario Evaluation of the Direct Method in Strapdown Airborne and Shipborne Gravimetry." In International Association of Geodesy Symposia. Berlin, Heidelberg: Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/1345_2020_127.
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AbstractIn recent years, it was shown that the quality of strapdown airborne gravimetry using a navigation-grade strapdown inertial measurement unit (IMU) could be on par with “classical” airborne gravimeters as the 2-axis stabilized LaCoste and Romberg S-type gravimeter. Basically, two processing approaches exist in strapdown gravimetry. Applying the indirect method (also referred to as “inertial navigation approach” or “one-step approach”), all observations – raw GNSS observations or position solutions, IMU specific force and angular rate measurements – are combined in a single Kalman Filter. Alternatively, applying the direct method (also referred to as “accelerometry approach” or “cascaded approach”), GNSS position solutions are numerically differentiated twice to get the vehicle’s kinematic acceleration, which is then directly removed from the IMU specific force measurement in order to obtain gravity. In the scope of this paper, test runs for the application of strapdown airborne and shipborne gravimetry are evaluated using an iMAR iNAV-RQH-1003 IMU. Results of the direct and the indirect methods are compared to each other. Additionally, a short introduction to the processing scheme of the Chekan-AM gravimeter data is given and differences between Chekan-AM and strapdown results of the shipborne campaigns are analysed. Using the same data set, the cross-over residuals suggest a similar accuracy of 0.39 mGal for the Chekan-AM and 0.41 mGal for the adjusted strapdown results (direct method).
Тези доповідей конференцій з теми "Angular rate measurement mode"
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Zhang, Zhiping, Siyuan Rong, and Shunli Li. "Sliding Mode Attitude Controller Design Based on ESO for Flexible Satellite without Angular Rate Measurement." In 2015 Fifth International Conference on Instrumentation & Measurement, Computer, Communication and Control (IMCCC). IEEE, 2015. http://dx.doi.org/10.1109/imccc.2015.417.
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Xia, Xiuwei, Qian Sun, Ya Zhang, Yanyan Wang, and Yue Zhang. "Ship deformation measurement based on angular rate matching method and Quasi-static model." In 2016 International Conference on Control, Automation and Information Sciences (ICCAIS). IEEE, 2016. http://dx.doi.org/10.1109/iccais.2016.7822449.
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Juhas, Brett D., Jessica M. Wong, Nicole J. Boroumand, and Paul H. Rigby. "Semi-Rigid Helmet Rotation Measurement Using Linear Accelerometers." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64677.
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The number of sensors placed on warfighters’ personal protective equipment (PPE) continues to increase each year. It is important to be able to accurately measure the dynamic response of PPE in order to characterize new sensors that are meant to track warfighter movement. In an effort to help predict head motion, a method has been developed to accurately measure the angular and linear acceleration of a semi-rigid helmet using four triaxial linear accelerometers. This four-accelerometer array configuration is based on the 3-2-2-2 nine accelerometer package (NAP) method and was tailored to accurately measure the helmet response during impact and blast overpressure events. Method development and testing were performed using U.S. Army Advanced Combat Helmets. Since angular motion calculation using the NAP method requires orthogonal sensor placement, it was necessary to revise the standard NAP sensor configuration to account for the geometric constraints of a helmet. Modal analysis was performed to determine the locations of least vibration, and shock tube and drop tests were conducted to investigate helmet flex during impacts. Knowledge concerning the dominant vibration modes of the helmet guided accelerometer placement and helped mitigate the effects of sensor data oscillation on the calculated angular motion. Local helmet deformation strongly depends on the impact site; several accelerometer array configurations were developed to account for various impact directions. Linear accelerations were measured and angular accelerations were calculated for guided free drop and shock tube tests in the laboratory. In guided free drop tests, the helmet and headform were dropped onto an anvil at various velocities and were allowed to freely bounce after impact. In shock tube tests, the helmet and headform were allowed to swing freely when subjected to a high shock wave simulating an IED blast. The modified NAP method was able to accurately measure the linear and angular acceleration of the helmet for both types of tests. The angular motion calculation was validated using a high-speed video camera recording the helmet response at 10,000 frames per second. Results were also compared to angular rate sensors available on the market. It was determined that with a detailed understanding of a semi-rigid body’s vibration and proper placement of linear accelerometers, angular acceleration during high-shock impacts can be accurately calculated for semi-rigid, irregular shaped objects. This accelerometer placement method has been applied to several other military grade helmets and been used in models predicting head motion from helmet motion data.
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Symons, Digby D., and Arnaud F. M. Bizard. "Measurement of Film Thickness for Continuous Fluid Flow Within a Spinning Cone." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20129.
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This paper reports experimental measurements of film thickness for continuous fluid flow within a spinning cone. The results are compared to analytical theory for thin film flow and found to be in good agreement. Spinning cones are used in various industrial process machines, including spinning cone distillation columns, centrifugal film evaporators and continuous centrifugal filters. In each case a fluid is fed continuously into the centre of a conical vessel which spins about a vertical axis with the cone apex pointing downwards. The fluid acquires the angular velocity of the cone and migrates up the internal wall of the cone under centrifugal force. Knowledge of the film thickness and flow velocity is often important in order to understand other performance parameters of the process such as evaporation or filtration rates. This paper aims to aid the design of new process machines by providing a mathematical model for film thickness that is validated by experimental results. Experiments have been conducted in which the angle of cone, angular velocity and input flow rate were all varied. Film thickness measurements were obtained via a novel optical method based on photographing the displacement of a projected grid on the surface of the flow within the cone. The method has the advantages of not disturbing the flow in any way and can provide thickness measurements over the whole cone depth. Measurements are also made insensitive to any transients by use of relatively long photographic exposures. Measurements are compared to analytical theory for axisymmetric, steady state, free-surface laminar flow of a Newtonian fluid in a spinning cone. The theory assumes the flow is thin but takes account of gravity. The theoretical model is found to be in good agreement with the experimental results.
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Hu, J. Stephen, Jian Sheng, Michele Guala, and Leonardo Chamorro. "High Speed PIV Measurement of Impinging Flow on a Horizontal Axis Wind Turbine." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72346.
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The focus of this paper is to characterize the upstream wake of a three bladed Horizontal Axis Wind Turbine (HAWT) and its interaction with the native structures within a turbulent boundary layer (TBL). The overarching question is the most prevailing length and time scales of coherent structures that would interact with a HAWT and how they would be affected. The implications include wall flow and structure interaction and flow induced noise generation in large scale turbo machineries. The experiments are performed on a turbine that has a 0.128 m rotor diameter, a hub height of 0.104 m and a tip speed ratio of 4. The HAWT model is placed in a large scale wind tunnel in a boundary layer with a thickness δ of ∼0.6 m. The boundary layer is generated by a 60 mm picket fence trip and developed over a smooth wall under thermally neutral conditions. Measurements are performed under ReD of 4 × 105 and 6 × 105. Both turbine geometries and flow conditions are scaled from operating conditions in the field. High speed Particle Image Velocimetry (PIV), turbine voltage output, and angular velocity measurements are conducted simultaneously, by which one could relate the upwind flow structures with the power output of the turbine. High speed PIV offer details in spatial and temporal characteristics of the impinging flow structures, whilst the voltage anemometer and tachometer provide instantaneous measurement of angular velocity of the turbine. PIV measurements are taken at a rate of 1500 image pairs per second with a 100 μs delay between laser pulses. Each sample area is 0.15 × 0.15 cm. Two locations up to two rotor diameters upwind are measured. Instantaneous voltage is taken at a sampling rate of 30 kHz and a sampling time of 60s to ensure sufficient temporal resolution and coverage. Ongoing analysis using conditional averaging based on extreme power output events will provide insights in assessing a HAWT performance in unsteady flow conditions.
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Ecker, Horst, and Stefan Litschauer. "Experimental Study on Lane Change Maneuvers With a Motorcycle." In ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22713.
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Abstract In this study, an innovative concept to measure the dynamic parameters of lane change maneuvers with motorcycles is presented and measurement results and conclusions are discussed An instrumented motorcycle is used for the experiments. Two independent measurement systems provide redundant data for obtaining precise readings of the vehicle position and the speed, for 3-axis accelerations and angular speeds, and more. Among these signals, the roll angle and the roll rate are especially important signals in this context. Measurements were carried out on public roads in a city and on highways, to allow for a broad range of speeds. The time series of the numerous tests were examined and analyzed with respect to the aforementioned signals and their correlation. Because of a regression analysis, analytical expressions could be derived for the lane change duration depending on the offset, for the maximum roll rate depending on the manoeuver intensity and finally for the roll rate and the roll angle as a function of time.
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Nagala, Daniel W., and Moncef Boufaida. "The Importance of Online Viscosity Measurement for Leak Detection and Other Simulation Applications." In 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0479.
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Knowledge of viscosity is an important property in fluid dynamics because it is a key factor in determining the amount of fluid that can be transported in a pipeline during a specific period of time. Dynamic viscosity, defined as the viscosity measured under force induced flow, not only describes the nature of the fluid but is also useful in predicting the behavior of the shear stress with respect to the rate of the angular deformation of the fluid. The addition of the viscous deceleration component in the linear momentum equation is important in describing the real fluid flow in the pipeline. The two factors producing viscosity are cohension and the rate of transfer of molecular momentum. The Reynolds number, which is based on the viscosity, is an important quantity which engineers use to determine if a flow is laminar or turbulent. Hence viscosity plays a major role in the generation of turbulence. Knowing the viscosity is also essential to improving system performance (volumetric efficiency and mechanical efficiency). Because viscosity typically varies among the different fluids transported in petroleum pipelines, it is widely considered that online measurement can be beneficial to pipeline operations. This is particularly true for complex applications that depend on a real-time fluid mechanics model for leak detection, batch tracking, and power optimization, among others.
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Treleaven, Nicholas C. W., Jialin Su, Andrew Garmory, and Gary J. Page. "The Response to Incident Acoustic Waves of the Flow Field Produced by a Multi-Passage Lean-Burn Aero-Engine Fuel Injector." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64527.
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Previous work has shown that compressible unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations, with suitable acoustic boundary conditions, are capable of correctly predicting the acoustic impedance of simplified fuel injectors. In this work the method developed is applied to simulating the acoustically forced flow in and downstream of a realistic multipassage fuel injector. The simulations are validated by comparing the impedance of the injector with data obtained experimentally by a multi-microphone technique. Such results can then be used in conjunction with a suitable low-order thermo-acoustic network model to predict the stability of combustors. However the validated simulations can also be used to reveal further details about the effect of acoustic forcing on the flow field. The velocity flow field produced by the injector with and without acoustic forcing is analysed using snapshot POD to determine the large scale energy containing structures within the flow. In the non-acoustically forced simulations it was found that the first four POD modes correspond to two rotating spiral modes, designated as the m = 1 and m = 2 modes with a peak frequency content of 450 Hz for the first mode and 1000 Hz for the second mode corresponding to experimental Hot-Wire measurements made in a separate study. It is hypothesised that these spiral modes will affect the atomisation, evaporation and mixing of the fuel in subsequent planned two-phase simulations. POD analysis of the flow subjected to 300 Hz, 300 Pa acoustic excitation shows that the first four POD modes correspond to similarly shaped spiral modes. The acoustic excitation is responsible for the appearance of 4 POD modes within the injector body that correspond to two push-pull velocity modes with axes of symmetry perpendicular to each other. The acoustic forcing also produces two additional POD modes that most likely represent the non-linear interaction between the push-pull and spiral modes. Further analysis of the fluctuations in pressure, mass flow rate, angular velocity and swirl number, within the passages and at the injector exit plane, show that the fluctuations in pressure and mass flow rate average across the passages while variations in angular velocity and swirl number sum across the passages. The relationship between mass flow rate, angular velocity and swirl number is discussed with reference to general observations of the sensitivity of flames to fluctuations in these quantities.
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Plohl, Gregor, and Günter Brenn. "Measurement of polymeric time scales from linear drop oscillations." In ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4686.
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The oscillating drop method allows material properties of liquids to be measured from damped drop oscillations. Theliterature discusses, e.g., the measurement of the liquid dynamic viscosity and the surface tension against the ambient medium, predominantly for Newtonian liquids. We use this method for measuring pairs of material properties of polymeric liquids. Pairs of properties may be measured, since the quantity measured is a complex frequency with a real and an imaginary part. For the measurements, individual drops are levitated in air by an ultrasonic levitator and imaged with a high-speed camera. Amplitude modulation of the ultrasound drives shape oscillations of the levitated drop. When the modulation is switched off, with the levitating force maintained, the drop performs free oscillations which are damped due to the liquid viscosity. The data acquired from the images recorded are the angular frequency and the damping rate which are used as an input into the characteristic equation of the oscillating drop. Our measurements intend to yield either two viscoelastic time scales with the zero-shear viscosity known, or one time scale and the zero-shear viscosity, with the other time scale known. The two time scales are the stress relaxation and the deformation retardation times. The latter is difficult to get for polymer solutions.The present contribution presents results from a large set of measurements of the deformation retardation time. Liquids studied are aqueous solutions of poly(acryl-amides) at varying concentration. The corresponding values of the zero-shear viscosity agree well with the values from shear rheometry. Values of the deformation retardation time differ substantially from the values commonly used in viscoelastic flow simulations. Furthermore, the measured values disagree with the predictions from the viscous-elastic stress splitting approach in linear viscoelasticity. With our study we will provide a consistent set of material properties for the Oldroyd-B model in linear viscoelasticity. This will beimportant for material modelling in viscoelastic spray simulations.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4686
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San Andrés, Luis, Michael Rohmer, and Scott Wilkinson. "Static Load Performance of a Water Lubricated Hydrostatic Thrust Bearing." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63385.
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In rotating equipment, thrust bearings aid to balance axial loads and control shaft position. In turbomachinery, axial loads depend on shaft speed and pressure rise/drop on the impellers. This paper details a water lubricated test rig for measurement of the performance of hydrostatic thrust bearings (HTBs). The rig contains two water lubricated HTBs (105 mm outer diameter), one is the test bearing and the other a slave bearing. Both bearings face the outer side of thrust collars of a rotor. The paper shows measurements of HTB axial clearance, flow rate, and recess pressure for operation with increasing static load (max. 1.4 bar) and supply pressure (max. 4.14 bar) at a rotor speed of 3 krpm (12 m/s OD speed). Severe angular misalignment, static and dynamic, of the bearing surface against its collar persisted and affected all measurements. The HTB axial clearance increases as the supply pressure increases and decreases quickly as the applied load increases. The reduction in clearance increases the flow resistance across the film lands thus reducing the through flow rate with an increase in recess pressure. In addition, an estimated bearing axial stiffness increases as the operating clearance decreases and as the supply pressure increases. Predictions from a bulk flow model qualitatively agree with the measurements. Alas they are not accurate enough. The differences likely stem from the inordinate tilts (static and dynamic) as well as the flow condition. The test HTB operates in a flow regime that spans from laminar to incipient turbulent. Quantification of misalignment at all operating conditions is presently a routine practice during operation of the test rig.