Compensation and Control of Dither-Smoothed Nonlinearities

Abstract

A novel approach to linearize nonlinearities commonly inherent in actuators is proposed in this paper. This approach solves the inverse of the nonlinearity without requiring its I/O relations as a one-on-one map, which is necessary for the current inverse-model method. By introducing the concept of the equivalent gain, the proposed method systematically finds the inverse model of the nonlinearity by solving a zero-finding problem. Discussions on the existence and uniqueness of the solution are given in this paper. A simulation example is presented to demonstrate how the task in finding the inverse of a complicated nonlinearity can be simplified by the proposed method. Experimental evaluations on a position servo system with conspicuous friction reveal that the dither-smoothed nonlinearities are still nonlinear, and compensating action like the proposed method is necessary for control systems using the dithering technology.

Enhanced Dielectric and Ferroelectric Properties of Donor (W6+, Eu3+) Substituted SBT Ferroelectric Ceramics

“…Therefore, besides the effect of grain size and reduction in oxygen vacancies, other factors also influence variation in remnant polarization. The decrease in the value of 2P r for x > 0.075, seems possibly due to the presence of secondary phases (observed in XRD diffractograms) which hampers the switching process of polarization [106][107][108][109][110]. Also this could be explained on the basis of the inference drawn w.r.t.…”

Effects of BaF₂ Addition on Properties of Strontium Barium Niobate Based Glass-Ceramics for Energy Storage Capacitors

“…The niobate-based glass-ceramics, which are focused more attention as another candidate for use in high energy density storage capacitors, have been carried out by several reporters. Shyu et al [4] reported that strontium barium niobate glass-ceramics at 1 KHz exhibited a dielectric constant of 351 and breakdown strength of 4.5 kV/cm sintered at 1000˚C. Zeng et al [5] found that the addition of 5 mol % BaF 2 decreased pores of SrO-BaO-Nb 2 O 5 -B 2 O 3 glass-ceramics, which are an important negative factor of improving breakdown strength.…”