Adaptive Identification of Angular Motion Model Parameters for LAAS Helicopter Benchmark

2007 ◽  
Author(s):  
Dimitri Peaucelle ◽  
Alexander L. Fradkov ◽  
Boris Andrievsky
Keyword(s):  
Angular Motion ◽  
Model Parameters ◽  
Motion Model ◽  
Adaptive Identification

scholarly journals Novel Aiming Method for Spin-Stabilized Projectiles with a Course Correction Fuze Actuated by Fixed Canards

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1135
Author(s):  
Cheng ◽  
Shen ◽  
Deng ◽  
Deng
Keyword(s):  
Traditional Method ◽  
Angular Motion ◽  
Hardware In The Loop ◽  
Motion Model ◽  
Simulation Based ◽  
Spinning Projectile ◽  
Gyroscopic Effects

Spin-stabilized projectiles with course correction fuzes actuated by fixed canards have the problem of great coupling in both the normal and lateral directions due to intensive gyroscopic effects, which leads to inconsistent maneuverability in different directions. Due to the limited correction ability, which results from the miniaturization of the fuze and fixed canards, a target-aiming method is proposed here to make full use of the correction ability of the canards. From analysis on how the canards work and building an angular motion model, the correction characteristics of a spinning projectile with fixed canards have been studied, and the inconsistent maneuverability in different directions of the projectile has been explained and used to help establish the proposed target aiming method. Hardware-in-the-loop simulation based on a 155 mm howitzer shows that when the correction ability of fixed canards is unchanged, the proposed method can improve the striking accuracy by more than 20% when compared to the traditional method.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Motion Model of Two-Wheel Differential Drive Mobile Robot under Variable Load

2014 ◽  
Vol 668-669 ◽  
pp. 352-356 ◽  
Author(s):  
Zhi Hu Ruan ◽  
Niu Wang ◽  
Bing Xin Ran
Keyword(s):  
Mobile Robot ◽  
State Space Model ◽  
Response Characteristic ◽  
Model Parameters ◽  
Variable Load ◽  
Motion Model ◽  
Actual System ◽  
Wheel Load ◽  
Differential Drive ◽  
Entire Vehicle

Based on kinematics characteristic of two-wheeled differential drive mobile robot (WMR) and response characteristic of fact motor drive system, this paper presents the analysis method of the equivalent rotation inertia, and the entire vehicle load is assigned to each wheel, and then the wheel load is converted into the corresponding equivalent rotation inertia of the motor shaft of each wheel, and motion model of WMR are obtained for combining with quasi-equivalent (QE) state space model of double-loop direct current motor systems under variable load and kinematics model of WMR under the load changes. By using speed response data of the actual system and combining with genetic algorithm to accurately identify the model parameters. Finally, through experiments results of the WMR motion model and the second order model respectively comparing with the actual system which demonstrates the effectiveness of the proposing method and model.

A search for constraints on lithospheric net rotation in 2D convection simulations

2021 ◽  
Author(s):  
Suzanne Atkins ◽  
Nicolas Coltice
Keyword(s):  
Reference Frames ◽  
Plate Motion ◽  
Model Parameters ◽  
Motion Model ◽  
Motion Models ◽  
The Third ◽  
The Earth ◽  
Geological Past ◽  
Wide Range ◽  
Third Dimension

<p>Net rotation is the process whereby the entire lithosphere can rotate with respect to the Earth’s mantle. The plates and continents retain their location with respect to each other, but they change their position with respect to global reference frames such as the Earth’s magnetic dipole, and structures in the Earth’s mantle such as plumes and hotspots. Constraining lithospheric net rotation is therefore one factor in building an absolute plate motion model. However, the amount of net rotation occurring at present day is poorly contained, and the drivers of net rotation are very poorly understood. Many absolute plate motion models therefore attempt to minimise net rotation, because there is no way to constrain rotation in the geological past. </p><p> </p><p>In previous geodynamical studies, the presence of thick continents and large viscosity contrasts were found to be controlling factors in the development of net rotation. We investigate the effects of different convection parameters and tectonic states on the magnitude and evolution of net rotation in 2D simulations. The use of 2D simulations allows us to run enough simulations to study a wide range of model parameters. We intend to compare our 2D conclusions with 3D simulations, to investigate how much of a difference the third dimension makes.</p><p> </p><p>We find that net rotation varies on much shorter timescales than any other geodynamic feature. Net rotation is not cleanly correlated with any tectonic behaviours or settings, and that the magnitude and duration is unpredictable. We do however find that the distribution of net rotation within the lifetime of a particular simulation is Gaussian, with standard deviation dependent on the viscosity structure and contrasts of the simulation, in agreement with previous studies. However, in contrast to previous studies, the presence and thickness of continents makes very little difference to the speed of lithospheric rotation, although this may be because we are working in 2D. If the 2D results are also relevant in 3D, net rotation is a continuously varying and unpredictable value, but with a predictable statistical range. This may provide a way to better constrain net rotation for plate motion models.</p>

LMI Based Control of Stick-Slip Oscillations in Drilling

2014 ◽  
Author(s):  
Matthew W. Harris ◽  
Behçet Açıkmeşe ◽  
Eric van Oort
Keyword(s):  
Linear Matrix Inequality ◽  
Convex Sets ◽  
Static Friction ◽  
Friction Torque ◽  
Angular Motion ◽  
Linear Matrix ◽  
Model Parameters ◽  
Matrix Inequality ◽  
Stick Slip ◽  
Linear Matrix Inequality Approach

This paper investigates control of stick-slip oscillations in drilling from a linear matrix inequality perspective. Stick-slip oscillations include a period of no angular motion at the bit caused by a large static friction torque followed by a period of rapid angular motion at the bit caused by a build up of torque in the drilling pipe. Many of the model parameters are uncertain but belong to convex sets, and the friction torques are not easily modeled. The linear matrix inequality approach facilitates design of state feedback controllers in the presence of polytopic uncertainties and can be optimized to reject disturbance effects relative to outputs. Results indicate that the linear matrix inequality approach leads to a simple controller, successfully alleviates the stick-slip problem, and is robust to uncertainties.

scholarly journals On the Method of Determining Onboard Ephemeris Data L1OC and L3OC GLONASS Aimed at Testing Positioning Algorithms in the GNSS Receiver

2020 ◽  
pp. 1-15
Author(s):  
Taliya G. Sharfunova ◽  
Daria A. Krasilnikova
Keyword(s):  
Prior Information ◽  
Least Squares Method ◽  
Initial Conditions ◽  
Model Parameters ◽  
Motion Model ◽  
Digital Form ◽  
Tikhonov’S Regularization ◽  
Navigation Equipment ◽  
Spacecraft Position

The paper considers a method of determining GLONASS ephemeris data in the L1OC and L3OC digital form aimed at testing the algorithms of accurate navigation determinations in consumer navigation equipment. The task of determining long-term motion model parameters of a navigation spacecraft is set as nonlinear problem of designing a matching model. This task is unstable and according to the analysis is categorized as incorrect. The application of a traditional least squares method to determine the long-term motion model parameters of a navigation spacecraft does not allow to obtain equally accurate solutions of condition equations system when initial conditions and/ or iterations amount have been changed. In this respect, Tikhonov’s regularization method has been carried out. It is based on the application of additional prior information. The obtained results have been tested by the comparison of estimated navigation spacecraft position according to the adjusted (speed and acceleration) ephemeris data, long-term motion model parameters and SP3 final reference ephemeris published on the SVOEVP website. The long-term motion model parameters of GLONASS navigation spacecraft that were defined by regularizing algorithms, have allowed to calculate the position of navigation spacecraft orbital grouping in terms of four-hours fitting intervals within 0,2 m tolerance (maximum deviations according to module of estimated navigation spacecraft position from SVOEVP SP3 reference ephemeris)

scholarly journals On the Analysis of the Phase Unwrapping Process in a D-InSAR Stack with Special Focus on the Estimation of a Motion Model

2019 ◽  
Vol 11 (19) ◽  
pp. 2295 ◽  
Author(s):  
Christina Esch ◽  
Joël Köhler ◽  
Karlheinz Gutjahr ◽  
Wolf-Dieter Schuh
Keyword(s):  
Minimum Cost ◽  
Large Data ◽  
Real Data ◽  
Search Space ◽  
Good Alternative ◽  
Phase Unwrapping ◽  
Phase Coherence ◽  
Model Parameters ◽  
Special Focus ◽  
Motion Model

This paper analyses the critical phase unwrapping step in a differential interferometric phase (D-InSAR) stack where both the solving of conventional methods and alternative approaches are discussed. It can be shown that including the temporal relationship between interferograms in the phase unwrapping step improves the results. This leads to the three-dimensional extended minimum cost flow algorithm. To unwrap the phase in a multitemporal way a motion model has to be considered. The estimation of these parameters is an important step. By default, the parameters are estimated in an iterative search process, where in each step, a linear program has to be solved. The best parameters are defined by the minimal costs. Often the choice of this search space is not straightforward. Furthermore, with this discrete optimization function, the solution is often not unique. This paper presents an alternative way to estimate the motion model parameters by maximizing a continuous function, the ensemble phase coherence. With the help of a closed-loop simulation and real data, both methods, the standard and the alternative way, are numerically compared and analyzed. Consequently, it is shown that maximizing the ensemble phase coherence is a good alternative to the established iterative procedure. It offers the advantage that the run time can be reduced considerably and is thus well suited in the processing of large data sets.

An Efficient Sport Video Segmentation System

2011 ◽  
Vol 467-469 ◽  
pp. 2042-2047
Author(s):  
Xin Bo Zhao ◽  
Xiao Chun Zou ◽  
Zhong Ma
Keyword(s):  
Video Segmentation ◽  
Model Parameters ◽  
Motion Model ◽  
Test Results ◽  
And Topology ◽  
Sport Video ◽  
Final Output ◽  
Feature Based ◽  
Error Accumulation ◽  
Motion Parameters

Digital sport video segmentation is an active area of research. And such an efficient sport video segmentation system is necessary. The system employs the feature-based motion estimator to estimate the video motion model parameters. Thus, we can use the result to compose the panorama. Project frames with motion parameters, the corresponding frames were connected and then stitched into a panoramic image according to infer the frames on a 2D manifold. For accurate alignment, we iterate between the motion estimator and topology determination to optimized parameters. Accuracy panorama composition is implemented to redress the error accumulation and achieve the pixel combination. After that, for the purpose of removing the foreground objects, we use the panorama estimation process. At last, we determine the sportsman segmentation masks that are the final output of the segmentation system. The test results showed that the proposed system is efficient.

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