There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The book presents sound coverage of the fundamentals of lightwave technology, along with material on pulse compression techniques and rare-earth-doped fiber amplifiers and lasers. The extensively revised chapters include information on fiber-optic communication systems and the ultrafast signal processing techniques that make use of nonlinear phenomena in optical fibers.New material focuses on the applications of highly nonlinear fibers in areas ranging from wavelength laser tuning and nonlinear spectroscopy to biomedical imaging and frequency metrology. Technologies such as quantum cryptography, quantum computing, and quantum communications are also covered in a new chapter.This book will be an ideal reference for: RD scientists involved with research on fiber amplifiers and lasers; graduate students and researchers working in the fields of optical communications and quantum information. * The only book on how to develop nonlinear fiber optic applications* Two new chapters on the latest developments; Highly Nonlinear Fibers and Quantum Applications* Coverage of biomedical applications

Applications of nonlinear fiber optics

Piezo-actuated stages have become more and more promising in nanopositioning applications due to the excellent advantages of the fast response time, large mechanical force, and extremely fine resolution. Modeling and control are critical to achieve objectives for high-precision motion. However, piezo-actuated stages themselves suffer from the inherent drawbacks produced by the inherent creep and hysteresis nonlinearities and vibration caused by the lightly damped resonant dynamics, which make modeling and control of such systems challenging. To address these challenges, various techniques have been reported in the literature. This paper surveys and discusses the progresses of different modeling and control approaches for piezo-actuated nanopositioning stages and highlights new opportunities for the extended studies.

Modeling and Control of Piezo-Actuated Nanopositioning Stages: A Survey

Combined with backstepping techniques, an observer-based adaptive consensus tracking control strategy is developed for a class of high-order nonlinear multiagent systems, of which each follower agent is modeled in a semi-strict-feedback form By constructing the neural network-based state observer for each follower, the proposed consensus control method solves the unmeasurable state problem of high-order nonlinear multiagent systems The control algorithm can guarantee that all signals of the multiagent system are semi-globally uniformly ultimately bounded and all outputs can synchronously track a reference signal to a desired accuracy A simulation example is carried out to further demonstrate the effectiveness of the proposed consensus control method

Observer-Based Adaptive Backstepping Consensus Tracking Control for High-Order Nonlinear Semi-Strict-Feedback Multiagent Systems

Pull-in instability as an inherently nonlinear and crucial effect continues to become increasingly important for the design of electrostatic MEMS and NEMS devices and ever more interesting scientifically. This review reports not only the overview of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices, but also the physical principles that have enabled fundamental insights into the pull-in instability as well as pull-in induced failures. Pull-in governing equations and conditions to characterize and predict the static, dynamic and resonant pull-in behaviors are summarized. Specifically, we have described and discussed on various state-of-the-art approaches for extending the travel range, controlling the pull-in instability and further enhancing the performance of MEMS and NEMS devices with electrostatic actuation and sensing. A number of recent activities and achievements methods for control of torsional electrostatic micromirrors are introduced. The on-going development in pull-in applications that are being used to develop a fundamental understanding of pull-in instability from negative to positive influences is included and highlighted. Future research trends and challenges are further outlined.

Electrostatic pull-in instability in MEMS/NEMS: A review

https://www.actapress.com/PaperInfo.aspx?paperId=456316

A Multi-Loop Control Strategy for Enhanced Nanopositioning

Positive acceleration, velocity and position feedback (PAVPF) control scheme has been successfully applied to piezoelectrically actuated nanopositioning systems to suppress resonance impelled vibrations. This control design shows a couple of improvements like high bandwidth control. The design framework is based on the principle in which damping is imparted by shifting the closed loop poles arbitrarily further into the left-half plane. In the proposed control design, a polynomial based pole placement approach was used to simultaneously damp and track the closed-loop poles to achieve a larger bandwidth control and reduced tracking error than the traditional PAVPF implementation as shown by experimental results.

Simultaneous Design of Positive Acceleration Velocity and Position Feedback Based Combined Damping and Tracking Control Scheme for Nanopositioners

Vibration problems are inherent to most precisionpositioning systems. These systems are lightly damped andhighly susceptible to mechanical resonance at any suddenchange in the voltage applied to the nanopositioning platform.These systems also exhibit nonlinearity, such as hysteresis andcreep. The traditional approach uses a combination of dampingcontrollers and tracking controllers to deal with nonlinearityand resonance respectively. The classical approach is based onsole use of the integral controller (l) or proportional integral(PI) as a tracking controller to treat nonlinearity; this paperemploys a hybrid feedback scheme, using the fuzzy logic con-troller as a correction tracking controller in in conjunction withthe conventional tracking controllers. The damping controllersutilised in this work to damp the mechanical resonance of thenanopositioning platform are the Integral Resonant Controller(IRC), the Positive Velocity and Position Feedback (PVPF),and the Positive Position Feedback Controller (PPF). Theproposed fuzzy logic controller delivers improved dynamictracking performance characteristics with less vibration incomparison with the conventional tracking method because thefuzzy logic controller can handle nonlinearity and vibrationvia its rules and membership functions. The use of fuzzyGaussian membership function can alleviate the appearanceof mechanical resonance.

/pdf/fuzzy-enhanced-dual-loop-control-strategy-for-precise-4l0ai01exh.pdf

Fuzzy-Enhanced Dual-Loop Control Strategy for Precise Nanopositioning

In this paper, a thorough framework for multiobjective design optimization of switched reluctance motor (SRM) is proposed. Selection of stator and rotor pole embrace coefficients is an essential step in the SRM design process since it influences torque output and torque ripple in SRM. The problem of determining optimal pole embrace is formulated as a multi-objective optimization problem with the objective of optimizing average torque, efficiency and torque ripple, and response surface models were obtained based on the genetic aggregation method. The results obtained by genetic aggregation response surface (GARS) and the non-dominated genetic algorithm (NSGA-II) were validated with the finite element method (FEM) model of the initial SRM. The optimized model displayed better efficiency profile over a wide speed range. The initial and optimized models recorded maximum efficiencies of 85% and 94.05%, respectively, at 2000 rpm. The efficiency values of 93.97–94.05% were achieved for the three pareto optimal candidates. The findings indicate the viability of the suggested strategy and support the use of GARS and NSGA-II as useful methods for addressing SRM key challenges.

/pdf/intelligent-optimization-of-switched-reluctance-motor-using-15neim24.pdf

Intelligent Optimization of Switched Reluctance Motor Using Genetic Aggregation Response Surface and Multi-Objective Genetic Algorithm for Improved Performance

http://www.nt.ntnu.no/users/skoge/prost/proceedings/ifac2014/media/files/0301.pdf

Sumeet S. Aphale

Papers

A Multi-Loop Control Strategy for Enhanced Nanopositioning

Simultaneous Design of Positive Acceleration Velocity and Position Feedback Based Combined Damping and Tracking Control Scheme for Nanopositioners

Fuzzy-Enhanced Dual-Loop Control Strategy for Precise Nanopositioning

Intelligent Optimization of Switched Reluctance Motor Using Genetic Aggregation Response Surface and Multi-Objective Genetic Algorithm for Improved Performance

A modified polynomial-based controller for enhancing the positioning bandwidth of nanopositioners.