فهرست مقالات Lyapunov theory

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  1 - Study and Design of a Fractional-order Terminal Sliding Mode Fault-‎Tolerant Control for Spacecraft
  Azam Hokmabadi
  In industrial systems, performance of a spacecraft is always affected by the presence of uncertainties and disturbances. In this paper, we study the application of a combination of Fault-Tolerant Control (FTC) designs based on fractional calculus and Terminal Sliding Mo چکیده کامل

  In industrial systems, performance of a spacecraft is always affected by the presence of uncertainties and disturbances. In this paper, we study the application of a combination of Fault-Tolerant Control (FTC) designs based on fractional calculus and Terminal Sliding Mode Control (FOTSMC) for a spacecraft in the presence of external disturbances. The proposed controller shows better control performance compared to existing terminal sliding mode control (TSMC).Moreover, in our design, the control law does not need a fault detection and isolation mechanism. The sliding mode control protects controller against disturbances and uncertainties while the fractional calculus provides robust performance. The performance of the proposed fractional-order controller, as compared with other controllers, is provided via numerical simulations. The results clearly demonstrate better performance of the fractional order terminal sliding mode control for an actuator fault in comparison with the terminal sliding mode control. The analytical stability analysis of the closed-loop control system is also provided by the Lyapunov direct method for fractional-order system. پرونده مقاله
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  2 - Dynamic Instability Analysis of Embedded Multi-walled Carbon Nanotubes under Combined Static and Periodic Axial Loads using Floquet–Lyapunov Theory
  Habib Ramezannejad Hemad Keshavarzpour Reza Ansari
  The dynamic instability of single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT) and triple-walled carbon nanotubes (TWCNT) embedded in an elastic medium under combined static and periodic axial loads are investigated using Floquet–Lyapuno چکیده کامل

  The dynamic instability of single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT) and triple-walled carbon nanotubes (TWCNT) embedded in an elastic medium under combined static and periodic axial loads are investigated using Floquet–Lyapunov theory. An elastic multiple-beam model is utilized where the nested slender nanotubes are coupled with each other through the van der Waals (vdW) interlayer interaction. Moreover, a radius-dependent vdW interaction coefficient accounting for the contribution of the vdW interactions between adjacent and non-adjacent layers is considered. The Galerkin’s approximate method on the basis of trigonometric mode shape functions is used to reduce the coupled governing partial differential equations to a system of extended Mathieu-Hill equations. Applying Floquet–Lyapunov theory, the effects of elastic medium, length, number of layers and exciting frequencies on the instability conditions of CNTs are investigated. Results show that elastic medium, length of CNTs, number of layer and exciting frequency have significant effect on instability conditions of multi-walled CNTs. پرونده مقاله