In this paper, robust adaptive neural network control is investigated for a class of multi-input-multi-output (MIMO) pure-feedback nonlinear system with unknown nonlinearities. The unknown nonlinearities could be come from unmodeled dynamics, modeling errors, or nonlinear time-varying uncertainties. Based on the backstepping design technique and the universal approximation property of the neura...

Spectral stability of multihump vector solitons in the Hamiltonian system of coupled nonlinear Schrödinger (NLS) equations is investigated both analytically and numerically. Using the closure theorem for the negative index of the linearized Hamiltonian, we classify all possible bifurcations of unstable eigenvalues in the systems of coupled NLS equations with cubic and saturable nonlinearities. ...

hard magnetic srfe12o19 (srm) nanoparticles were synthesized by a facile sonochemical reaction. the magnetic nanoparticles were then added to acrylonitrile-butadiene-styrene, polystyrene, polycarbonate, and poly sulfone to make magnetic nanocomposites. the magnetic properties of the samples were also investigated using an alternating gradient force magnetometer. the strontium ferrite nanopartic...

This paper aims to highlight the critical role of robot manipulators in industrial applications and elucidate challenges associated with achieving high-precision control. In particular, detrimental effects nonlinear friction on are discussed. To overcome this challenge, a novel compensation controller (FCC) that combines time-delay estimation (TDE) an adaptive fuzzy logic system (AFLS) is propo...

This paper builds an innovative composite world trade-cycle index by means of a dynamic factor model for short-term forecasts trade growth both goods and (usually neglected) services. Trade indicators are selected using multidimensional approach, including Bayesian averaging techniques, correlations, Granger non-causality tests in linear vector autoregression framework. To overcome real-time fo...

This paper considers the problem of stabilization of discrete-time systems with actuator nonlinearities. Specifically, dynamic, output feedback control design for discrete-time systems with time-varying, sectorbounded, input nonlinearities is addressed. The proposed framework is based on a linear matrix inequality approach and directly accounts for robust stability and robust performance over t...

Abstract: We propose and analyze a robust adaptive fuzzy controller for nonlinear systems without a priori knowledge of the sign of the input gain function. No assumptions are made about the type of nonlinearities of the system, except that such nonlinearities are smooth. The uncertain nonlinearities are captured by the fuzzy systems that have been proven to be universal approximators. The prop...

Atomic force microscopes employ stacked or cylindrical piezoceramic actuators to achieve sub-angstrom resolution. While these devices produce excellent set-point accuracy, they exhibit hysteresis and constitutive nonlinearities even at low drive levels. Feedback mechanisms can mitigate the deleterious effects of these nonlinearities for low frequency operation but such techniques fail at higher...

Our hearing organ, the cochlea, evidently poises itself at a Hopf bifurcation to maximize tuning and amplification. We show that in this condition several effects are expected to be generic: compression of the dynamic range, infinitely sharp tuning at zero input, and generation of combination tones. These effects are "essentially" nonlinear in that they become more marked the smaller the forcin...

Many of the paradoxes encountered in the Copenhagen interpretation of quantum mechanics can be shown to have plausible, more logical parallels in terms of nonlinear dynamics and chaos. These include the statistical exponential decay laws, interpretations of Bell’s inequalities, spontaneous symmetry breaking, and perhaps diffractive behavior and even quantization itself. Many of the so-called al...