scholarly journals Combinatory Attitude Determination Method for High Rotational Speed Rigid-Body Aircraft

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Liangliang An ◽  
Liangming Wang ◽  
Ning Liu ◽  
Jian Fu
Keyword(s):  
Rigid Body ◽  
Rotational Speed ◽  
Attitude Determination ◽  
Unscented Kalman Filter ◽  
The State ◽  
Determination Method ◽  
State Equations ◽  
High Rotational Speed ◽  
Motion Equations ◽  
Accuracy Measurement

In this paper, we present a novel multisensor combinatory attitude determination method that enables high-accuracy measurement of the attitude of a high rotational speed rigid-body aircraft. We analyze the external moments of the aircraft during flight and develop the method using theoretical deductions based on the motion equations of a rigid body rotating around the centroid. The proposed method fuses the data measured from GPS, gyrometer, and magnetometer and uses the improved unscented Kalman filter (UKF) algorithm to perform filtering. First, appropriate assumptions and simplifying approximations are made for around-centroid motion equations of a rigid body according to the motion characteristics of the high rotational speed aircraft. Using these assumptions and approximations, the constraint equations between the Euler attitude angles and flight-path angle, trajectory deflection angle are derived to serve as the state equation. Second, the roll angle with error is calculated using the geomagnetic field model and the geomagnetic intensity measured by a three-axis magnetometer and then fused with the angular velocity information obtained from the gyroscope for constructing the measurement equations. Finally, the state equations are discretized using the Runge–Kutta method during the UKF prediction stage, improving the prediction accuracy. Simulation results show that the proposed method can effectively determine the attitude information of the high rotational speed aircraft, achieving high level of reliability and accuracy thanks to the combination of information from GPS, gyroscope, and magnetometer.

A Novel Approach for Buckling Analysis of Pretwisted Spatially Curved Beams by State Equations

2016 ◽  
Vol 16 (05) ◽  
pp. 1550011 ◽  
Author(s):  
S. R. Kuo ◽  
Judy P. Yang ◽  
Y. B. Yang
Keyword(s):  
Rigid Body ◽  
Buckling Analysis ◽  
The State ◽  
Curved Beams ◽  
State Equations ◽  
State Matrix ◽  
Current Configuration ◽  
Matrix Operations ◽  
Novel Approach ◽  
Force Equilibrium

Based on force equilibrium and rigid body considerations, a novel approach is proposed for deriving the state equations and then the buckling equations of pretwisted spatially curved beams. Based on statical consideration of an infinitesimal element from the last calculated configuration [Formula: see text] to the current configuration [Formula: see text], a set of condition equations for the state matrix is derived. Next, by enforcing the rigid body rule for the beam, another set of condition equations for the state matrix is derived. From these two sets of equations, the state matrix of the beam is derived that leads directly to the buckling differential equations. The merit of the proposed approach is that it only requires simple differential and matrix operations. No hidden errors are possible because no higher-order terms need to be treated. In addition, a direct link is established between the straight and curved beam theories. Finally, examples are provided to demonstrate the application of the theory to the buckling analysis of various curved beams, including the helical ones.

Spacecraft Attitude and System Identification Using Marginal Reduced UKF Utilizing the Sun and Calibrated TAM Sensors

2012 ◽  
Vol 225 ◽  
pp. 417-422 ◽  
Author(s):  
Maryam Kiani ◽  
Seid H. Pourtakdoust
Keyword(s):  
Kalman Filter ◽  
Parameter Identification ◽  
Attitude Determination ◽  
Unscented Kalman Filter ◽  
Computational Cost ◽  
Nonlinear Estimation ◽  
Inertia Tensor ◽  
Sensor Calibration ◽  
State Equations ◽  
Calibration Parameters

This paper deals with attitude determination, parameter identification and reference sensor calibration simultaneously. A LEO satellite’s attitude, inertia tensor as well as calibration of Three-Axis-Magnetometer (TAM) are estimated during a maneuver designed to satisfy persistency of excitation condition. For this purpose, kinematic and kinetic state equations of spacecraft motion are augmented for the determination of inertia tensor and TAM calibration parameters including scale factors, misalignments and biases along three body axes. Attitude determination is a nonlinear estimation problem. Unscented Kalman Filter (UKF) as an advanced nonlinear estimation algorithm with good performance can be used to estimate satellite attitude but its computational cost is considerably larger than the widespread, low accuracy, Extended Kalman Filter (EKF). Reduced Sigma Points Filters provide good solutions and also decrease run time of UKF. However, in contrast to nonlinear problem of attitude determination, parameter identification and sensor calibration have linear dynamics. Therefore, a new Marginal UKF (MUKF) is proposed that combines the utility of Kalman Filter with Modified UKF (MMUKF). The proposed MMUKF utilizes only 14 sigma points to achieve the complete 25-dimensional state vector estimation. Additionally, a Monte Carlo simulation has demonstrated a good accuracy for concurrent estimation of attitude, inertia tensor as well as TAM calibration parameters in significantly less time with respect to sole utilization of the UKF.

General Identities for Parameterizations of SO(3) With Applications

2014 ◽  
Vol 81 (7) ◽  
Author(s):  
Anton H. J. de Ruiter ◽  
James Richard Forbes
Keyword(s):  
Rigid Body ◽  
Orthogonal Group ◽  
Attitude Determination ◽  
Unit Length ◽  
Spacecraft Attitude ◽  
Euler Angles ◽  
Motion Equations ◽  
Rotation Matrices ◽  
Special Orthogonal Group ◽  
Lagrange’S Equation

Rotation matrices, which are three-by-three orthonormal matrices with determinant equal to plus one, constitute the special orthogonal group of rigid-body rotations, denoted SO(3). Owing to the three-by-three nature of rotation matrices plus their orthonormality constraint, parameterizations are often used in favor of rotation matrices for computations and derivations. For example, Euler angles and Rodrigues parameters are common three-parameter unconstrained parameterizations, while unit-length quaternions are a popular four-parameter constrained parameterization. In this paper various identities associated with the parameterization of SO(3) are considered. In particular, we present six identities, three related to unconstrained parameterizations and three related to constrained parameterizations. We also discuss rotation matrix perturbations. The utility of these identities is highlighted when deriving the motion equations of a rigid body using Lagrange's equation. We also use them to examine some issues associated with spacecraft attitude determination.

Performances of HSK Tool Interfaces under High Rotational Speed

CIRP Annals ◽  
2001 ◽  
Vol 50 (1) ◽  
pp. 281-284 ◽  
Author(s):  
T. Aoyama ◽  
I. Inasaki
Keyword(s):  
Rotational Speed ◽  
High Rotational Speed

The Coupling Characteristic of HSK Tool-Holder/Spindle Interface for High-Speed NC Machine Tool

2014 ◽  
Vol 590 ◽  
pp. 121-125 ◽  
Author(s):  
Wen Kai Jie ◽  
Jian Chen ◽  
Deng Sheng Zheng ◽  
Gui Cheng Wang
Keyword(s):  
Machine Tool ◽  
Rotational Speed ◽  
High Speed ◽  
Nonlinear Finite Element Method ◽  
High Rotational Speed ◽  
Tool Holder ◽  
Nc Machine Tool ◽  
Machine Tool Accuracy ◽  
Nc Machine ◽  
Coupling Characteristic

The coupling characteristic of the tool-holder/spindle interface in high speed NC machine has significant influence on machine tool accuracy and process stability. With the example of HSK-E63, based on nonlinear finite element method (FEM), the coupling characteristic of the tool-holder/spindle interface under high rotational speed was investigated, the influence of interference, clamping force and rotational speed on the contact stress and the sectional area of clearance were discussed in detail. The results can be used as theoretical consideration to design and optimize the high speed tool-holder/spindle interface.

Spherical Simplex Unscented Kalman Filter-Based Jumping and Static Interacting Multiple Model

2017 ◽  
Vol 32 (04) ◽  
pp. 1850010
Author(s):  
Yi Pan ◽  
Hui Ye ◽  
Keke He
Keyword(s):  
Kalman Filter ◽  
Nonlinear Filtering ◽  
System Parameter ◽  
Unscented Kalman Filter ◽  
Continuous System ◽  
The State ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Real Time System ◽  
Spherical Simplex

A modified interacting multiple model (IMM) method called spherical simplex unscented Kalman filter-based jumping and static IMM (SSUKF-JSIMM) is proposed to solve the problem of nonlinear filtering with unknown continuous system parameter. SSUKF-JSIMM regards the continuous system parameter space as a union of disjoint regions, and each region is assigned to a model. For each model, under the assumption that the parameter belongs to the corresponding region, one sub-filter is used to estimate the parameter and the state when the parameter is presumed to be jumping, and another sub-filter is used to estimate the parameter and the state when the parameter is presumed to be static. Considering that spherical simplex unscented Kalman filter (SSUKF) is more suitable for a real-time system than the unscented Kalman filter (UKF), SSUKFs are adopted as the sub-filters of SSUKF-JSIMM. Results of the two SSUKFs are fused as the estimation output of the model. Experimental results show that SSUKF-JSIMM achieves higher performance than IMM, SIR, and UKF in bearings-only tracking problem.

scholarly journals Investigations of Inducers Operating With High Rotational Speed

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Björn Gwiasda ◽  
Matthias Mohr ◽  
Martin Böhle
Keyword(s):  
Rotational Speed ◽  
Test Bench ◽  
Pressure Rise ◽  
Working Fluid ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Performance Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Performance

Suction performance, pressure rise, and efficiency for four different inducers are examined with computational fluid dynamics (CFD) simulations and experiments performed with 18,000 rpm and 24,000 rpm. The studies originate from a research project that includes the construction of a new test bench in order to judge the design of the different inducers. This test bench allows to conduct experiments with a rotational speed of up to 40,000 rpm and high pressure ranges from 0.1 bar to 40 bar with water as working fluid. Experimental results are used to evaluate the accuracy of the simulations and to gain a better understanding of the design parameter. The influence of increasing the rotating speed from 18,000 rpm to 24,000 rpm on the performance is also shown.

The Forced Oscillations of Submerged Bodies

2003 ◽  
Vol 125 (4) ◽  
pp. 710-715
Author(s):  
Angel Sanz-Andre´s ◽  
Gonzalo Tevar ◽  
Francisco-Javier Rivas
Keyword(s):  
Rigid Body ◽  
Small Amplitude ◽  
Center Of Mass ◽  
Rigid Body Dynamics ◽  
The Body ◽  
Central Point ◽  
Modal Testing ◽  
Forced Oscillations ◽  
Motion Equations ◽  
Marine Applications

The increasing use of very light structures in aerospace applications are given rise to the need of taking into account the effects of the surrounding media in the motion of a structure (as for instance, in modal testing of solar panels or antennae) as it is usually performed in the motion of bodies submerged in water in marine applications. New methods are in development aiming at to determine rigid-body properties (the center of mass position and inertia properties) from the results of oscillations tests (at low frequencies during modal testing, by exciting the rigid-body modes only) by using the equations of the rigid-body dynamics. As it is shown in this paper, the effect of the surrounding media significantly modifies the oscillation dynamics in the case of light structures and therefore this effect should be taken into account in the development of the above-mentioned methods. The aim of the paper is to show that, if a central point exists for the aerodynamic forces acting on the body, the motion equations for the small amplitude rotational and translational oscillations can be expressed in a form which is a generalization of the motion equations for a body in vacuum, thus allowing to obtain a physical idea of the motion and aerodynamic effects and also significantly simplifying the calculation of the solutions and the interpretation of the results. In the formulation developed here the translational oscillations and the rotational motion around the center of mass are decoupled, as is the case for the rigid-body motion in vacuum, whereas in the classical added mass formulation the six motion equations are coupled. Also in this paper the nonsteady motion of small amplitude of a rigid body submerged in an ideal, incompressible fluid is considered in order to define the conditions for the existence of the central point in the case of a three-dimensional body. The results here presented are also of interest in marine applications.

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