Soroush Arghavan

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… Show more

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. Show less

Experiments have been conducted in order to investigate the linearity of system response and system behavior of a macro-scale ring-type vibratory gyroscope. Particular emphasis is placed on examining the effects of environmental fluctuation in angular rate, mass mismatch and the linearity of system response. It is shown that the system natural frequency decreases with input angular rate and mass mismatch. It is also revealed that the system exhibits a more efficient dissipative behavior when… Show more

Experiments have been conducted in order to investigate the linearity of system response and system behavior of a macro-scale ring-type vibratory gyroscope. Particular emphasis is placed on examining the effects of environmental fluctuation in angular rate, mass mismatch and the linearity of system response. It is shown that the system natural frequency decreases with input angular rate and mass mismatch. It is also revealed that the system exhibits a more efficient dissipative behavior when subjected to stochastic angular rate fluctuations with fixed intensity at higher input angular rates. Show less

Effect of stochastic fluctuations in angular velocity on the stability of two DOF ring-type MEMS gyroscopes is investigated. The governing Stochastic Differential Equations 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 are employed for validation purposes due to lack of similar analytical or experimental data… Show more

Effect of stochastic fluctuations in angular velocity on the stability of two DOF ring-type MEMS gyroscopes is investigated. The governing Stochastic Differential Equations 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 are employed for validation purposes due to lack of similar analytical or experimental data. The stability investigation predicts that the threshold fluctuation intensity increases nonlinearly with damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.
Furthermore, construction, electrical improvements, testing and troubleshooting of a macro-scale ring-type gyroscope prototype is completed. Experiments have been conducted in order to investigate the linearity of system response, system behavior when subjected to environmental fluctuation in angular rate as well as the effects of angular rate and mass mismatch on system natural frequency. It is shown that the system natural frequency decreases with input angular rate and mass mismatch. It is also revealed that the system exhibits a more efficient damping behavior when subjected to stochastic speed fluctuations with fixed intensity at higher input angular rates. Show less

This article presents a new design for thermal management of Li-ion batteries in electric vehicles through forced convection. This design carries the advantage of relatively uniform cooling of cells, while employing a simple geometry. In addition to a baseline case, a parametric study has been conducted on the contributing parameters such as the rate of heat generation in the battery, as well as cooling air velocity and temperature. It is shown that temperature distribution in the battery… Show more

This article presents a new design for thermal management of Li-ion batteries in electric vehicles through forced convection. This design carries the advantage of relatively uniform cooling of cells, while employing a simple geometry. In addition to a baseline case, a parametric study has been conducted on the contributing parameters such as the rate of heat generation in the battery, as well as cooling air velocity and temperature. It is shown that temperature distribution in the battery remains relatively unaffected although the value of temperature is changed with the operating conditions. While higher heat generation rate reduces temperature uniformity, increasing the inlet velocity is shown to lower cell temperature and increase temperature uniformity. Location of the maximum temperature will also be pushed downstream with higher velocities. Temperature of the battery can also be slightly reduced by an increase in the inlet turbulence intensity, however, temperature uniformity is compromised. Show less