For the nonlinear systems preceded by smart actuators which exhibit hysteresis nonlinearities, it is a challenge to mitigate effects of the hysteresis. By utilizing an operator-based Prandtl-Ishlinskii model and a neural network approximator, a robust adaptive control scheme is developed for a general class of continuous-time nonlinear dynamic systems with unknown hysteresis nonlinearities. The...

Optical bistability is reported in InP/GaInAsP equilateral-triangle-resonator (ETR) microlasers, which are fabricated by planar technology. For a 30 mum side ETR microlaser with a 2-mum-wide output waveguide connected to one of the vertices of the ETR, hysteresis loops are observed for the output power versus the injection current from 215 to 235 K. The laser output spectra are measured in the ...

Ionic polymer-metal composites (IPMCs) generate large bending motions under a low driving voltage (about 1 V). In this paper quasi-static actuation of IPMC is investigated with the goal of precise positioning. It is found that IPMC exhibits hysteresis between its bending curvature and the applied quasi-static voltage. The Preisach operator is proposed to model the hysteresis, and its density fu...

We report the results of magnetic measurements on austenitic stainless steels and duplex stainless steels using a magnetic hysteresis scaling technique. Unlike saturation hysteresis loops, this scaling technique, which uses a set of minor hysteresis loops, can be used in low measurement fields. We show that there is a universal scaling power law between minor-loop parameters, which is independe...

The hysteresis or internal friction in the deformation of crystalline solids stressed cyclically is studied from the viewpoint of collective dislocation dynamics. Stress-controlled simulations of a dislocation dynamics model at various loading frequencies and amplitudes are performed to study the stress-strain rate hysteresis. The hysteresis loop areas exhibit a maximum at a characteristic freq...

Adaptive Optics (AO) systems are widely used in many scientific and medical applications, such as astronomy, laser systems and microscopes, in order to improve the resolution of the image by actively sensing and compensating the optical aberration in the system. This paper aims at improving the performance of a closed-loop AO system with Piezo-driven Deformable Mirror (PDM) and high-sampling-ra...

Using a Ginzburg–Landau–Devonshire type model, the pyroelectric property and hysteresis loop are studied for a composite ferroelectric thin film that contains an insertion of a different type of ferroelectric material in parallel connection with the host ferroelectric film material. If these two types of ferroelectric materials are polarized along the same direction, there are two peaks occur i...

Theoretical models are adapted to describe the hysteresis effects seen in the electrical characteristics of carbon nanotube field-effect transistors. The ballistic transport model describes the contributions of conduction energy sub-bands over carbon nanotube field-effect transistor drain current as a function of drain-source and gate-source voltages as well as other physical parameters of the ...

This paper deals with the characterization, the modeling and the closedloop control of multivariable piezoelectric actuators, with an application to a 3-DOF piezoelectric tube scanner, widely used in precise positioning. These actuators are typified by hysteresis and creep nonlinearities, badly damped oscillation and strong couplings between their axis. First, during the modeling, we propose to...

This paper deals with designing a repetitive controller (RC) for tracking periodic reference trajectories for systems that exhibit hysteresis, such as piezoelectric actuators used in nanopositioning systems. Hysteresis can drastically limit the performance of an RC designed around a linear dynamics model, and thus the effect of hysteresis on the closed-loop stability of RC is analyzed and the a...