scholarly journals Angular Velocity Perception Threshold and Sense of Presence for a Three Degrees of Freedom (DOF) Driving Simulator in Virtual Environment

2018 ◽  
Author(s):  
Baris Aykent ◽  
Jean-Remy Chardonnet ◽  
Frederic Merienne ◽  
Andras Kemeny
Author(s):  
Yan Li ◽  
Fuhai Duan ◽  
Liang Fan ◽  
Ying Yan

Three-floated gyroscope with the advantages of high accuracy has been widely used in platform inertial navigation system. To investigate the influence of specific force on the measured angular velocity of a gyroscope with a rotor supported on gas-lubricated bearings, a static error model considering three-degrees-of-freedom displacement of the rotor is proposed through numerical computation. Firstly, the conical Reynolds equation incorporated with the Fukui and Kaneko’s slip model is adopted and solved by the finite difference method, and the bearing force, caused by specific force, are obtained for each rotor displacement. Secondly, the error of gyroscope measured angular velocity is calculated from bearing force and rotor displacement. Finally, the relationship between the error and specific force is obtained by regression analysis, and the static error model of the gyroscope is proposed. To simplify the ternary regression analysis to binary, two intermediate parameters, radial interference torque and circumferential angle between interference torque and specific force, are introduced. Numerical results show that interference torque is approximately π/2 ahead of specific force in circumferential direction with fz > 0, and π/2 behind specific force with fz < 0, and that a large interference torque is produced when the specific force in radial and axial direction are both large. The error model provides a rapid prediction of the error caused by rotor displacement by three-degrees-of-freedom specific force.


2018 ◽  
Vol 51 (13) ◽  
pp. 372-377 ◽  
Author(s):  
Juan E. Andrade García ◽  
Alejandra Ferreira de Loza ◽  
Luis T. Aguilar ◽  
Ramón I. Verdés

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.


Author(s):  
A. H. S. Iyer ◽  
M. H. Colliander

Abstract Background The trend in miniaturisation of structural components and continuous development of more advanced crystal plasticity models point towards the need for understanding cyclic properties of engineering materials at the microscale. Though the technology of focused ion beam milling enables the preparation of micron-sized samples for mechanical testing using nanoindenters, much of the focus has been on monotonic testing since the limited 1D motion of nanoindenters imposes restrictions on both sample preparation and cyclic testing. Objective/Methods In this work, we present an approach for cyclic microcantilever bending using a micromanipulator setup having three degrees of freedom, thereby offering more flexibility. Results The method has been demonstrated and validated by cyclic bending of Alloy 718plus microcantilevers prepared on a bulk specimen. The experiments reveal that this method is reliable and produces results that are comparable to a nanoindenter setup. Conclusions Due to the flexibility of the method, it offers straightforward testing of cantilevers manufactured at arbitrary position on bulk samples with fully reversed plastic deformation. Specific microstructural features, e.g., selected orientations, grain boundaries, phase boundaries etc., can therefore be easily targeted.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.


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