Dynamical properties of discrete solitons in nonlinear Schrödinger lattices with saturable nonlinearity are studied in the framework of the one-dimensional discrete Vinetskii-Kukhtarev model. Two stationary strongly localized modes, centered on site (A) and between two neighboring sites (B), are obtained. The associated Peierls-Nabarro potential is bounded and has multiple zeros indicating stro...

Structural flexibility in spacecraft can degrade the accuracy of the attitude control system. With this motivation in mind, we compare the performance of inertia-free attitude control laws for a spacecraft with an undamped discrete flexible mode and demonstrate robustness with respect to unmodeled spacecraft dynamics and actuator saturation. First the equations of motion are derived using Lagra...

Compensated summation algorithms are designed to improve the accuracy of ill-conditioned sums. They are based on algorithms, such as FastTwoSum, which are proved to provide, with rounding to nearest, the sum of two floating-point numbers and the associated rounding error. Discrete stochastic arithmetic enables one to estimate rounding error propagation in numerical codes. It requires a random r...

We report the label-free, real-time optical detection of Influenza A virus particles. Binding of single virions is observed from discrete changes in the resonance frequency/wavelength of a whispering-gallery mode excited in a microspherical cavity. We find that the magnitude of the discrete wavelength-shift signal can be sufficiently enhanced by reducing the microsphere size. A reactive sensing...

This work deals with a sliding mode control scheme for discrete time nonlinear systems. The control law synthesis problem is subdivided into a finite number of subproblems of lower complexity, which can be solved independently. The sliding mode controller is designed to force the system to track a desired reference and to eliminate unwanted disturbances, compensating at the same time matched an...

Robotic and embedded systems have become increasingly pervasive in applications ranging from space probes and life support systems to robot assistants. In order to act robustly in the physical world, robotic systems must be able to detect changes in operational mode, such as faults, whose symptoms manifest themselves only in the continuous state. In such systems, the state is observed indirectl...

A case study on automotive lane centering control is examined in Hybrid Event-B (an extension of Event-B that includes provision for continuously varying behaviour as well as the usual discrete changes of state). This allows aspects beyond the reach of a discrete Event-B treatment to be more deeply investigated. Lane centering offers particular challenges concerning how the monitoring of contin...

Purpose – The purpose of this paper is to develop sliding mode control with linear and nonlinear manifolds in discrete-time domain for robot manipulators. Design/methodology/approach – First, a discrete linear sliding mode controller is designed to an n-link robot based on Gao’s reaching law. In the second step, a discrete terminal sliding mode controller is developed to design a finite time an...

In this paper, an H∞ sliding mode control (SMC) problem is studied for a class of discrete-time nonlinear stochastic systems with multiple data packet losses. The phenomenon of data packet losses, which is assumed to occur in a random way, is taken into consideration in the process of data transmission through both the state feedback loop and the measurement output. The probability for the data...