scholarly journals Kinematics in the Information Age

Mathematics ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 148 ◽  
Author(s):  
Brendon Smeresky ◽  
Alexa Rizzo ◽  
Timothy Sands
Keyword(s):  
Attitude Control ◽  
Technology Development ◽  
Information Age ◽  
Direction Cosine ◽  
Euler Angle ◽  
Computational Time ◽  
Step Size ◽  
Aerospace Applications ◽  
Space Age ◽  
Digital Computers

Modern kinematics derives directly from developments in the 1700s, and in their current instantiation, have been adopted as standard realizations…or templates that seem unquestionable. For example, so-called aerospace sequences of rotations are ubiquitously accepted as the norm for aerospace applications, owing from a recent heritage in the space age of the late twentieth century. With the waning of the space-age as a driver for technology development, the information age has risen with the advent of digital computers, and this begs for re-evaluation of assumptions made in the former era. The new context of the digital computer defines the use of the term “information age” in the manuscript title and further highlights the novelty and originality of the research. The effects of selecting different Direction Cosine Matrices (DCM)-to-Euler Angle rotations on accuracy, step size, and computational time in modern digital computers will be simulated and analyzed. The experimental setup will include all twelve DCM rotations and also includes critical analysis of necessary computational step size. The results show that the rotations are classified into symmetric and non-symmetric rotations and that no one DCM rotation outperforms the others in all metrics used, yielding the potential for trade space analysis to select the best DCM for a specific instance. Novel illustrations include the fact that one of the ubiquitous sequences (the “313 sequence”) has degraded relative accuracy measured by mean and standard deviations of errors, but may be calculated faster than the other ubiquitous sequence (the “321 sequence”), while a lesser known “231 sequence” has comparable accuracy and calculation-time. Evaluation of the 231 sequence also illustrates the originality of the research. These novelties are applied to spacecraft attitude control in this manuscript, but equally apply to robotics, aircraft, and surface and subsurface vehicles.

scholarly journals Sinusoidal Trajectory Generation Methods for Spacecraft Feedforward Control

2020 ◽  
Author(s):  
Kyle A. Baker
Keyword(s):  
Feedforward Control ◽  
Trajectory Generation ◽  
Direction Cosine ◽  
Euler Angle ◽  
Self Awareness ◽  
Spacecraft Dynamics ◽  
Step Size ◽  
Mathematical Basis ◽  
Simulink Model ◽  
High Level

The following is a brief walkthrough of material related to the modeling of spacecraft dynamics with feedforward control as the self-awareness declaration for deterministic artificial intelligence. Specifically, the focus will be on the analysis of various sinusoidal trajectory methods. The methods utilized are the basic MATLAB sine generation function, a Taylor series implementation, and two alternate algorithms for higher speed, lower precision and lower speed, higher precision implementations. The chapter features a brief summary of previous work investigating the impact of step size on Euler and Body angles. This is followed by a high level overview of Euler angle theory, quaternions, direction cosine matrices, kinematics, and dynamics to form a mathematical basis for the core material. With the numerical basis for the modeling efforts outlined, the results of running a SIMULINK model of spacecraft dynamics with feedforward control will be briefly analyzed and explored. The analysis will cover the impacts of varying step size with various sinusoidal trajectory generation methodologies.

Simulation of Deformation Behavior and Microstructure Evolution during Hot Forging of TC11 Titanium Alloy

2018 ◽  
Vol 385 ◽  
pp. 449-454 ◽  
Author(s):  
Artem Alimov ◽  
Dmitry Zabelyan ◽  
Igor Burlakov ◽  
Igor Korotkov ◽  
Yuri Gladkov
Keyword(s):  
Titanium Alloy ◽  
Microstructure Evolution ◽  
Technology Development ◽  
Hot Forging ◽  
Industrial Case Study ◽  
Aerospace Applications ◽  
Heating And Cooling ◽  
Tc11 Titanium Alloy ◽  
Kinetics Of

Finite element method is the most powerful tool for development and optimization of the metal forming processes. Analysis of titanium alloy critical parts should include the prediction of microstructure since their mechanical and technological properties essentially depend on the type and parameters of the microstructure. The technological process of parts production for aerospace applications is multi-operational and consists of deformation, heating and cooling stages. Therefore, it is necessary to simulate the microstructure evolution to obtain high quality parts. In presented paper FE simulation coupled with microstructure evolution during hot forging of TC11 titanium alloy has been performed by QForm FEM code. Constitutive relationships, friction conditions and microstructure evolution model have been established using the experiments. The kinetics of phase transformations has been described by the Johnson-Mehl-Avrami-Kolmogorov (JMAK) phenomenological model. The approach is illustrated by industrial case study that proved its practical applicability and economic advantages for technology development of titanium alloy critical parts.

scholarly journals Design And Analysis Of Attitude Control Algorithm For Low Earth Orbiting Satellite With Magnetic Torquer Concepts Using Non- Linear Unscented Kalman Filter

2018 ◽  
Vol 7 (2.18) ◽  
Author(s):  
RAJA MUNUSAMY ◽  
Ugur Guven ◽  
Om Prakash
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Unscented Kalman Filter ◽  
Euler Angle ◽  
Attitude Estimation ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Attitude Control System ◽  
Attitude Stabilization ◽  
Attitude Sensor

Attitude control system plays the important role for to maintain the satellite to desired orientation. To control the satellite it is necessary to do the attitude stabilization. Attitude stabilization achieved by Star sensor, sun sensor, Earth sensors. Attitude control is mainly used for antenna pointing accuracy, camera focus to earth surface and solar panel pointing toward sun. Due to tumbling effect satellite will rotate all the direction in the space. To maintain the orientation of the satellite it is necessary to design the attitude determination and control. Satellite consider as the rigid body. Inertia matrix describes the rigid body dynamics.  The orientation of the satellite determine by Euler angle and Quaternion. Low earth orbit satellite will have enormous amount of aerodynamic drag stinking the satellite body and gravitational attraction another problem. Because of that satellite dwell time is reduced. It means satellite more time spending particular part of the earth. The attitude estimation is measures by the orientation of vectors. Attitude estimation means to find the position and orientation of flying object with respect to the fixed reference of reference. Vector remains considered in the frame of reference to compute for find the orientation of the body of the satellite in the inertial reference system. Earth is an inertial reference frame, Satellite is a body frame. Attitude sensor used to measure the satellite orientation in the reference frame. This will help in accurately predicting the orbit deviation and a control system to correct if any by providing the satellite momentum means ‘mass in motion’ changes in a body rapidly in Low earth orbit due to centripetal force acting on a satellite. Attitude control system (ACS) need the numerical simulation to find the required torque demand by the help of difference between reference input (Attitude) signal and feedback signal measure by attitude sensor to trim the control surface maintain the actuator required orientation . The results will consist of two parts the first part consisting of the attitude estimation using Euler angle and Quaternion method, second part consist of estimate the control torque from magnetic torquer and error estimation using non-linear filter (Unscented Kalman Filter) with MATLAB simulation.

Comprehensive Analysis of Fluid-Structure Interactive Schemes for Modeling Aircraft Water Impact Scenarios

2020 ◽  
Author(s):  
Suraj Jain Megharaja ◽  
Javid Bayandor
Keyword(s):  
Experimental Studies ◽  
Structural Response ◽  
Computational Time ◽  
Water Impact ◽  
Computationally Efficient ◽  
Aerospace Applications ◽  
Computationally Intensive ◽  
Emergency Scenarios ◽  
The Right ◽  
Effective Transfer

Abstract Aircraft emergency water landings (ditching) are uncommon but remain an ever-present possibility. Therefore, crashworthiness standards as part of the Federal Aviation Regulations demand such situations to be accounted for during the certification phase. The criteria require aircraft to prove its ability to survive ditching and be able to float after impact for a duration long enough for the passengers to be rescued. In emergency scenarios, it is preferred to choose an open body of water as the landing location as opposed to hard terrain. It would be prohibitively expensive to test impacts of this nature to cover all required certification cases. The data collection can also be a tedious process. Due to these hindrances, performing numerical validation of aircraft water ditching (fluid-solid) interactions has become more important than ever. In case of hard terrain impact, most of the energy is absorbed by the frame of an aircraft. However, in water impacts, the initial load is distributed over the skin. As a result, the ability of an aircraft to withstand crash becomes dependent on the strength of the shear panels to allow an effective transfer of impact energy to damage-absorbing members and mechanisms before failling. Large full-scale simulations to capture the structural response of an aircraft under severe impact loading however can be computationally intensive. This work focusses on comparative analysis of numerical strategies for assessing fluid-structural Interactions. Two of the methods considered are Lagrangian, and Arbitrary Lagrangian and Eulerian (ALE) schemes. For preliminary validations, the experimental studies performed by other research groups have been used to investigate the effect of mesh refinement and computational time on the Lagrangian and ALE schemes. These simulations will provide a basis for selecting the right formulations when developing fluid-solid interactive models for aerospace applications. Based on the results of the studies conducted, the most computationally efficient scheme was then used to perform the simulations of an aircraft fuselage section when impacting water in an emergency landing situation. The fuselage model used in this project was pre-validated against a rigid terrain experimental drop test before it was applied to the ditching studies. Overall, this investigation aims at assessing advanced modeling techniques and approaches that can pave the way for analysis-assited water impact certification and, ultimately, certification by analysis.

scholarly journals Advanced Autonomous Underwater Vehicles Attitude Control with L 1 Backstepping Adaptive Control Strategy

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4848
Author(s):  
Yuqian Liu ◽  
Jiaxing Che ◽  
Chengyu Cao
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Attitude Control ◽  
Autonomous Underwater Vehicles ◽  
Euler Angle ◽  
Underwater Vehicles ◽  
Linearization Method ◽  
Backstepping Control ◽  
Feedback Form ◽  
Adaptive Control Strategy

This paper presents a novel attitude control design, which combines L 1 adaptive control and backstepping control together, for Autonomous Underwater Vehicles (AUVs) in a highly dynamic and uncertain environment. The Euler angle representation is adopted in this paper to represent the attitude propagation. Kinematics and dynamics of the attitude are in the strict feedback form, which leads the backstepping control strategy serving as the baseline controller. Moreover, by bringing fast and robust adaptation into the backstepping control architecture, our controller is capable of dealing with time-varying uncertainties from modeling and external disturbances in dynamics. This attitude controller is proposed for coupled pitch-yaw channels. For inevitable roll excursions, a Lyapunov function-based optimum linearization method is presented to analyze the stability of the roll angle in the operation region. Theoretical analysis and simulation results are given to demonstrate the feasibility of the developed control strategy.

La nuova frontiera del viaggio: l’esplorazione del cosmo

2021 ◽  
pp. 25-45
Author(s):  
Marco Romoli
Keyword(s):  
Future Development ◽  
Technology Development ◽  
High Mountains ◽  
The Earth ◽  
The World ◽  
Space Age ◽  
The Universe

The human drive for knowledge, together with the technology development, often accelerated by warfare, has opened new frontiers to exploration. Once the exploration of the Earth globe came to an end with the conquest of the geographical poles, of the high mountains, and the ocean deeps, mankind developed new attention to Space and the exploration of the Universe, not only by means of ground based telescopes, but with rockets, unmanned and manned satellites and spacecrafts. In the mid of XX century, the drivers are similar to those that pushed the Nations of XV century to discover the world: geopolitics strategies, hunger for resources and knowledge, conquer and adventure. We are just at the beginning. This is a brief overview of the Space Age history and of the present and future development.

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