Comparative Research on Attitude Algorithm of the Multi-Rotor UAV Based on the Gyroscope

2014 ◽  
Vol 651-653 ◽  
pp. 668-671
Author(s):  
Xin Zhang ◽  
Lan Yu
Keyword(s):  
Comparative Research ◽  
High Reliability ◽  
Euler Angle ◽  
High Accuracy ◽  
Mems Gyroscope ◽  
Autonomous Flight ◽  
Attitude Angle ◽  
The Stability ◽  
Mean Square Errors ◽  
Angle Calculation

Obtaining the flight attitude of high accuracy, high reliability is a prerequisite for achieving the autonomous flight of the multi-rotor UAV. MEMS gyroscope can solve attitude angle individually. The paper adopts Euler angle and quaternion algorithms respectively to calculate attitude angle of the multi-rotor UAV. The flight experiment shows that the quaternion algorithm can guarantee the accuracy and the stability of the attitude angle calculation. The root-mean-square errors of the pinch roll and heading angles which are calculated by the quaternion algorithm are 2.947o, 3.606o and 9.769o, which can meet the demand for the autonomous flight of the multi-rotor UAV.

scholarly journals Code Calibration of the Eurocodes

2021 ◽  
Vol 11 (12) ◽  
pp. 5474
Author(s):  
Tuomo Poutanen
Keyword(s):  
High Reliability ◽  
High Accuracy ◽  
Variable Load ◽  
Reliability Model ◽  
Safety Factors ◽  
Rounding Errors ◽  
Code Calibration ◽  
Load Factors ◽  
Characteristic Values

This article addresses the process to optimally select safety factors and characteristic values for the Eurocodes. Five amendments to the present codes are proposed: (1) The load factors are fixed, γG = γQ, by making the characteristic load of the variable load changeable, it simplifies the codes and lessens the calculation work. (2) Currently, the characteristic load of the variable load is the same for all variable loads. It creates excess safety and material waste for the variable loads with low variation. This deficiency can be avoided by applying the same amendment as above. (3) Various materials fit with different accuracy in the reliability model. This article explains two options to reduce this difficulty. (4) A method to avoid rounding errors in the safety factors is explained. (5) The current safety factors are usually set by minimizing the reliability indexes regarding the target when the obtained codes include considerable safe and unsafe design cases with the variability ratio (high reliability/low) of about 1.4. The proposed three code models match the target β50 = 3.2 with high accuracy, no unsafe design cases and insignificant safe design cases with the variability ratio 1.07, 1.03 and 1.04.

scholarly journals An Analytical Method for Dynamic Wave-Related Errors of Interferometric SAR Ocean Altimetry under Multiple Sea States

2021 ◽  
Vol 13 (5) ◽  
pp. 986
Author(s):  
Yao Chen ◽  
Mo Huang ◽  
Yuanyuan Zhang ◽  
Changyuan Wang ◽  
Tao Duan
Keyword(s):  
Electromagnetic Scattering ◽  
Analytical Method ◽  
Wave Spectrum ◽  
High Accuracy ◽  
Sea State ◽  
Error Budget ◽  
Ocean Topography ◽  
Mean Square Errors ◽  
Dynamic Wave ◽  
Wide Swath

The spaceborne interferometric synthetic aperture radar (InSAR) is expected to measure the sea surface height (SSH) with high accuracy over a wide swath. Since centimeter-level accuracy is required to monitor the ocean sub-mesoscale dynamics, the high accuracy implies that the altimetric errors should be totally understood and strictly controlled. However, for the dynamic waves, they move randomly all the time, and this will lead to significant altimetric errors. This study proposes an analytical method for the dynamic wave-related errors of InSAR SSH measurement based on the wave spectrum and electromagnetic scattering model. Additionally, the mechanisms of the dynamic wave-related errors of InSAR altimetry are analyzed, and the detailed numerical model is derived. The proposed analytical method is validated with NASA’s Surface Water and Ocean Topography (SWOT) project error budget, and the Root-Mean-Square Errors (RMSEs) are in good agreement (0.2486 and 0.2470 cm on a 0.5 km2 grid, respectively). Instead of analysis for a typical project, the proposed method can be applied to different radar parameters under multiple sea states. The RMSEs of Ka-band under low sea state, moderate sea state, and high sea state are 0.2670, 1.3154, and 6.6361 cm, respectively. Moreover, the RMSEs of X-band and Ku-band are also simulated and presented. The experimental results demonstrate that the dynamic wave-related errors of InSAR altimetry are not sensitive to the frequencies but are sensitive to the sea states. The error compensation method is necessary for moderate and higher sea states for centimetric accuracy requirements. This can provide feasible suggestions on system design and error budget for the future interferometric wide-swath altimeter.

An Efficient Galerkin BEM to Compute High Acoustic Eigenfrequencies

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Mario Durán ◽  
Jean-Claude Nédélec ◽  
Sebastián Ossandón
Keyword(s):  
Numerical Method ◽  
Integral Equations ◽  
High Frequency ◽  
High Accuracy ◽  
Integral Representations ◽  
Stability And Convergence ◽  
Symmetric Matrices ◽  
Frequency Interval ◽  
Numerical Treatment ◽  
The Stability

An efficient numerical method, using integral equations, is developed to calculate precisely the acoustic eigenfrequencies and their associated eigenvectors, located in a given high frequency interval. It is currently known that the real symmetric matrices are well adapted to numerical treatment. However, we show that this is not the case when using integral representations to determine with high accuracy the spectrum of elliptic, and other related operators. Functions are evaluated only in the boundary of the domain, so very fine discretizations may be chosen to obtain high eigenfrequencies. We discuss the stability and convergence of the proposed method. Finally we show some examples.

scholarly journals A Numerical Study on Travel Time Based Hydraulic Tomography Using the SIRT Algorithm with Cimmino Iteration

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 909 ◽  
Author(s):  
Pengxiang Qiu ◽  
Rui Hu ◽  
Linwei Hu ◽  
Quan Liu ◽  
Yixuan Xing ◽  
...  
Keyword(s):  
Travel Time ◽  
Numerical Study ◽  
Correlation Coefficients ◽  
Structural Similarity ◽  
Iteration Step ◽  
Reconstruction Technique ◽  
Hydraulic Tomography ◽  
Iterative Reconstruction Technique ◽  
The Stability ◽  
Mean Square Errors

Travel time based hydraulic tomography is a technique for reconstructing the spatial distribution of aquifer hydraulic properties (e.g., hydraulic diffusivity). Simultaneous Iterative Reconstruction Technique (SIRT) is a widely used algorithm for travel time related inversions. Due to the drawbacks of SIRT implementation in practice, a modified SIRT with Cimmino iteration (SIRT-Cimmino) is proposed in this study. The incremental correction is adjusted, and an iteration-dependent relaxation parameter is introduced. These two modifications enable an appropriate speed of convergence, and the stability of the inversion process. Furthermore, a new result selection rule is suggested to determine the optimal iteration step and its corresponding result. SIRT-Cimmino and SIRT are implemented and verified by using two numerical aquifer models with different predefined (“true”) diffusivity distributions, where high diffusivity zones are embedded in a homogenous low diffusivity field. Visual comparison of the reconstructions shows that the reconstruction based on SIRT-Cimmino demonstrates the aquifer’s hydraulic features better than the conventional SIRT algorithm. Root mean square errors and correlation coefficients are also used to quantitatively evaluate the performance of the inversion. The reconstructions based on SIRT-Cimmino are found to preserve the connectivity of the high diffusivity zones and to provide a higher structural similarity to the “true” distribution.

The Remote Monitoring System of Highway Slope Safety

2014 ◽  
Vol 687-691 ◽  
pp. 747-750
Author(s):  
Cheng Hao Han ◽  
Jun Ping Zhu ◽  
Hao Li ◽  
Xing Tong Wang
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Remote Monitoring ◽  
High Reliability ◽  
Field Work ◽  
High Accuracy ◽  
Real Time Monitoring ◽  
Remote Monitoring System ◽  
Anchor System ◽  
Slope Condition

As it is impossible to conduct real-time monitoring on slope condition of highways, a remote monitoring system has been specially designed. Making use of GPRS technology, Labview and solar power, the system has realized nobody monitor on slope anchor system, automatic collection of slope pressure and displacement data. It enjoys advantages such as high-accuracy, real-time monitoring and high-reliability. Among existing effective monitoring ways, massive man-power is needed for on-field work, but real-time monitoring is still left to be achieved.

Suppressing the Noise in Measured Signals for the Control of Helicopters

2019 ◽  
Vol 18 (01) ◽  
pp. 1950002 ◽  
Author(s):  
Deepali Y. Dube ◽  
Hiren G. Patel
Keyword(s):  
Adaptive Filter ◽  
Mimo Systems ◽  
Sliding Mode ◽  
Euler Angle ◽  
Linear Matrix ◽  
Frequency Spectra ◽  
Non Linear ◽  
The Future ◽  
The Stability ◽  
Non Linear System

This paper concerns with the non-linear system having multiple-inputs multiple-outputs (MIMO). The plant mainly comprises: bench-top helicopter, tail and main rotor of a helicopter system. The dynamics are presented with control methodologies where a conventional strategy proves the instability of the system while the deadbeat and sliding mode control with linear matrix inequality regulates the future estimates. There have been disturbances like presence of unwanted ripples in the output of the non-linear systems (in case of stability also after 100[Formula: see text]s) and in the tracking of states accurately by updating the minimization error regularly. These problems originate mainly from the rotor section and are visited carefully by studying the dynamics of the blade, whereas, the design of filter makes the solution more appealing. The adaptive filter is capable of handling the frequency spectra of noise (reducing noise by 10[Formula: see text]dB), Euler angle deviations and travel angle accurately. Also, the stability analysis does not confirm the behavior in the case of bounded and a varying range of initial angular velocity. Hence, the problem of fluctuations is overcome by deadbeat and SMC-LMI approach which not only improved the ripples but also allowed the final response of the future states to be more exact and noiseless. As the previous research involved in position tracking (either translational or rotational) of these MIMO systems was concerned with software tools like MATLAB. This paper justifies its validation tested experimentally on OPAL RT hardware. The key findings involve the comparison of frequency spectra, the Euler deviation plot compared to CSL Helicopter and the three set-point variations providing accuracy in results in four modes — desired, actual, with controller-without filter and with controller-with filter. The use of adaptive filter with controllers have encouraged the suppression of noisy waveforms in the bench-top system very smoothly. The details regarding hardware setup are also discussed.

PERFORMANCE OF THE ANALYTICAL PLOTTER

1963 ◽  
Vol 17 (2) ◽  
pp. 205-211
Author(s):  
T. J. Blachut
Keyword(s):  
Early Stage ◽  
Statistical Treatment ◽  
Measuring System ◽  
Stage Of Development ◽  
Pointing Accuracy ◽  
Analytical Accuracy ◽  
The Stability ◽  
Extensive Experimental Data ◽  
Mean Square Errors ◽  
Very High

In spite of the lack of extensive experimental data at this, in a sense, early stage of development, some very interesting indications of the eventual performance of the Analytical Plotter can be seen. The accuracy of the measuring system is very high; monocular grid measurements gave mean square errors of 2.5 - 3.5 μ. The stability is even better, repetition of readings being constant within 2 to 3 μ, that is, within the pointing accuracy. The accuracy of the complete system may be improved by using experimental corrections and proper statistical treatment of redundant observations. Complete relative and absolute orientations can be carried out in 10 to 15 minutes or less with analytical accuracy. Further economical advantages result from the use of the inherent computer capabilities to solve auxiliary problems and to carry out pertinent “real time” operations, such as automatic control of the plotting table.

Modeling and Error Compensation of MEMS Gyroscope Dynamic Output Data within the Whole Temperature Range

2011 ◽  
Vol 311-313 ◽  
pp. 768-771 ◽  
Author(s):  
Yan Shun Zhang ◽  
Shu Wei Wang
Keyword(s):  
Data Model ◽  
Rbf Neural Network ◽  
Performance Testing ◽  
High Accuracy ◽  
Output Data ◽  
Mems Gyroscope ◽  
Temperature Range ◽  
Dynamic Output ◽  
C 50 ◽  
Experimental Data Collection

In this paper, the output data of MEMS gyroscope ADRX150 under different input angular velocity within the temperature range of -30°C~50°C is collected and analyzed. Taking the nonlinear and random characteristics of the output data of MEMS gyroscope ADRX150 into account, the dynamic output data model based on RBF neural network is established, which is training and taking the performance testing with the experimental data collection. The results indicate that, the model has high accuracy and good generalization ability.

Nonlinear Bifurcation Analysis of a Single-DoF Model of a Robotic Arm Subject to Digital Position Control

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Giuseppe Habib ◽  
Giuseppe Rega ◽  
Gabor Stepan
Keyword(s):  
Center Manifold ◽  
Position Control ◽  
High Accuracy ◽  
Industrial Applications ◽  
Critical Parameters ◽  
Robotic Arm ◽  
Control Force ◽  
Local Center ◽  
The Stability ◽  
Stability Limits

Precision and stability in position control of robots are critical parameters in many industrial applications where high accuracy is needed. It is well known that digital effect is destabilizing and can cause instabilities. In this paper, we analyze a single DoF model of a robotic arm and we present the stability limits in the parameter space of the control gains. Furthermore we introduce a nonlinearity relative to the saturation of the control force in the model, reduce the dynamics of the nonlinear map to its local center manifold, study the bifurcation along the stability border and identify conditions under which a supercritical or subcritical bifurcation occurs. The obtained results explain some of the typical instabilities occurring in industrial applications. We verify the obtained results through numerical simulations.

scholarly journals Experiments on an Ultrastable Gas Journal Bearing

1967 ◽  
Vol 89 (4) ◽  
pp. 433-438 ◽  
Author(s):  
S. B. Malanoski
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Design Data ◽  
Attitude Angle ◽  
Angle Data ◽  
The Stability ◽  
Data Design ◽  
Gas Journal Bearing

Shallow grooving in a herringbone pattern has been proposed to enhance the stability of both gas and liquid-lubricated journal bearings. It has been shown theoretically that this possibility is particularly advantageous for unloaded journal bearings. This paper describes corroborating experiments. The experiments included the running of an unloaded bearing up to speeds of 60,000 rpm and the collection of steady-state load-displacement, attitude angle data at intermediate speeds up to and including 60,000 rpm. No sign of bearing whirl instability was detected. There was good correlation between theoretical and experimental data. Design data for the partially grooved journal bearing is included for future designs.

Sign in / Sign up

Export Citation Format

Share Document