scholarly journals Physics-based Learning for Aircraft Dynamics Simulation

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Yang Yu ◽  
Houpu Yao ◽  
Yongming Liu

The accurate prediction of flight trajectories is crucial for the real-time prognostics of air transportation system. However, the computation costs of predictions can be expensive or even prohibitive especially for a large number of aircrafts in the air traffic system. This study proposes the concept of physics-based learning, a hybrid approach based on data-driven learning and physical models, as a computationally efficient method for the simulation of aircraft dynamics. The physics-based learning integrates the underlying physics of dynamical systems into learning models such as neural networks to reduce the training and simulation costs. The application of physics-based learning for simulating aircraft dynamics is demonstrated using a recently introduced physics-aware network known as the deep residual recurrent neural network (DR-RNN) on a Boeing 747-100 aircraft. The aircraft dynamics are described using a six degrees-of-freedom aircraft model. The DR-RNN is first trained using the simulated responses of the aircraft and then the trained network is used to predict the response of aircraft under arbitrary control inputs and disturbances. The results show that the DR-RNN can accurately predict aircraft responses and has excellent extrapolation capabilities. Moreover, the DR-RNN exhibits superior computation efficiency compared with a classical numerical method, the fourth-order Runge-kutta method, highlighting its suitability in serving as surrogating models for aircraft dynamical systems.

2011 ◽  
Vol 188 ◽  
pp. 671-674
Author(s):  
Yi Nan Lai ◽  
M.J. Zhao ◽  
Y. Dai ◽  
M.Z. Lai ◽  
X. Lai

According to the requirements of the ground demonstration test for small-sized docking mechanism, a set of ground test platform was designed, which can simulate the weightless environment of space and provide six degrees of freedom for the docking mechanism. This paper elaborated the structure and working process of the test platform, and used the way of rigid-flexible coupling to analysis the test platform in dynamics simulation by ADAMS. The mechanical properties of the platform’s key parts during the collision process were obtained


2012 ◽  
Vol 251 ◽  
pp. 231-234
Author(s):  
Gang Li ◽  
Ya Dong Chen ◽  
Bo Wang ◽  
Wan Shan Wang

In this paper, we present the modeling and dynamics simulation of a six-DOF tunnel segment erector for tunnel boring machine (TBM), which is performed in the virtual prototype platform. The 3D virtual assembling model of a tunnel segment erector is built based on Pro/E software according to its design parameters such as structure and size. After the interference inspection, the model is imported into ADAMS through the interface module of Mech/Pro. The model is simplified and optimized reasonably and various constraints are applied under variety working conditions. The results of simulation show that the design has six degrees of freedom movement capacity which meets the design requirements. At the same time the dynamics characteristics of drives and the forces of each part are obtained and they will provide a boundary condition for strength check and basis for the power system design which is important for the further optimal design.


Author(s):  
David Schowalter ◽  
Indradeep Ghosh ◽  
Sung-Eun Kim ◽  
Ahmad Haidari

Vortex-induced vibration of a circular cylinder with two degrees-of-freedom (2-DOF) is numerically studied using a mixed Lagrangian-Eulerian approach at several Reynolds numbers. The computations were carried out using a parallelized finite-volume Navier-Stokes solver based on a multidimensional linear reconstruction scheme that allows use of unstructured meshes. The effects of turbulence are modeled using an approach based on unsteady Reynolds-averaged Navier-Stokes (URANS) equations and a hybrid approach often referred to as detached eddy simulation (DES). In order to better understand the potential sources of the prediction error, a systematic verification and validation of the numerics and the physical models is attempted in this study with problems of progressively increasing complexity.


2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Peter J. K. Cameron ◽  
Peter H. Rogers ◽  
John W. Doane ◽  
David H. Gifford

Applications and research utilizing supercavitation for high-speed underwater flight has motivated study of the phenomenon. In this work, a small scale laboratory experiment for studying supercavitating projectiles has been designed, built, and tested. Similar existing experimental work has been documented in literature but using large, elaborate facilities, or has been presented with ambiguous conclusions from test results. The projectiles were 63.5 mm in length and traveled at speeds on the order of 145 m/s. Measurement techniques are discussed and used to record projectile speed, supercavity dimensions, and target impact location. Experimental observations are compared with a six degrees-of-freedom dynamics simulation based on theoretical models presented in literature for predicting supercavity shape and hydrodynamic forces on the supercavitating projectile during flight. Experimental observations are discussed qualitatively, along with quantitative statistics of the measurements made. Successful operation of the experiment has been demonstrated and verified by agreement with theoretical models.


2005 ◽  
Vol 29 (4) ◽  
pp. 679-690 ◽  
Author(s):  
Liguo Huo ◽  
Luc Baron

This paper introduces the concept of functional redundancy of serial manipulators, and presents a new resolution scheme to solve such redundant robotic tasks requiring less than six degrees-of-freedom. Instead of projecting the secondary task onto the null space of the Jacobian matrix in order to take advantage of the redundancy, the twist of end-effector is directly decomposes into two orthogonal subspaces where the main and secondary tasks lie, respectively. The algorithm has shown to be computationally efficient and well suited to solve functionally-redundant robotic tasks, such as arc-welding.


2013 ◽  
Vol 415 ◽  
pp. 451-456
Author(s):  
Shao Hua Xu ◽  
Wen Cheng Cao ◽  
Li Zeng

The vibrating modes of vibration screen box can be divided into single degree of freedom excitation and multiple degrees of freedom excitation. This paper puts forward the conception of multiple degrees of freedom excitation and sets up the dynamic equation of multiple degrees of freedom excitation vibration screen while the characteristics of one freedom vibration screen are summarized. Through the MATLAB programming language, using the four order Runge-Kutta method, we do a dynamics simulation research on an instance for this type of vibration screen, and analyze the characteristics of this type of vibration screen.


Author(s):  
Takuji Nakashima ◽  
Makoto Tsubokura ◽  
Syumei Matsuda ◽  
Yasuaki Doi

A one-way coupled analysis was used to investigate both the unsteady aerodynamic forces on a simplified heavy-duty truck in strong wind gusts and their effects on its motion. The vehicle model for the dynamics simulation was extended to six degrees of freedom (6DoF). First, a transitional aerodynamics simulation was conducted for the simplified truck with a fixed vehicle attitude but subject to a sudden crosswind. Based on the visualized results of this aerodynamics simulation, flow phenomena generating transitional aerodynamic forces and moments are discussed, especially those acting in the vertical direction. While the truck was running into the crosswind region, the growth and breakdown of a large-scale vortex above the container generated a transitional behavior of aerodynamic lift and pitching moment. Next, time series of the six components of the aerodynamic forces and moments were input into the vehicle dynamics simulation. By comparing the results with those of a quasi-steady aerodynamics simulation, the effect of transitional aerodynamics on vertical motions was clarified, with the largest difference found in a rolling motion. Moreover, the effect of considering 6DoF was investigated by also conducting the vehicle dynamics simulation with 3DoF. The consideration of dynamics in the vertical direction changed the estimation of tire forces, which were related to a vertical load on the tire. Finally, the effects of considering 6DoF were also identified for horizontal motions.


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