Position sensors with nanometer resolution are a key component of many precision imaging and fabrication machines. Since the sensor characteristics can define the linearity, resolution and speed of the machine, the sensor performance is a foremost consideration. The first goal of this article is to define concise performance metrics and to provide exact and approximate expressions for error sources including non-linearity, drift and noise. The second goal is to review current position sensor technologies and to compare their performance. The sensors considered include: resistive, piezoelectric and piezoresistive strain sensors; capacitive sensors; electrothermal sensors; eddy current sensors; linear variable displacement transformers; interferometers; and linear encoders.

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A review of nanometer resolution position sensors: Operation and performance

In this study, the actuator load force of a nanopositioning stage is utilized as a feedback variable to achieve both tracking and damping. The transfer function from the applied actuator voltage to the measured load force exhibits a zero-pole ordering that greatly simplifies the design and implementation of a tracking and damping controller. Exceptional tracking and damping performance can be achieved with a simple integral controller. Other outstanding characteristics include guaranteed stability and insensitivity to changes in resonance frequency. Experimental results on a high-speed nanopositioner demonstrate an increase in the closed-loop bandwidth from 210 Hz (with an integral controller) to 2.07 kHz (with a force-feedback control). Gain margin is simultaneously improved from 5 dB to infinity.

Nanopositioning System With Force Feedback for High-Performance Tracking and Vibration Control

http://library.um.ac.id/free-contents/downloadpdf.php/buku/the-science-and-engineering-of-materials-by-donald-r-askeland-28398.pdf

The Science and engineering of materials / by Donald R. Askeland

Electromagnetic Fields and Waves

The Handbook of Smart Textiles aims to provide a comprehensive overview in the field of smart textile describing the state of the art in the research sector as well as the well-established techniques applied in industries. The handbook is planned to cover from fundamental theories, experimental techniques, characterization methods, as well as real applications with successful commercialized examples. The book is structured in a way in which it is appropriate for graduate students, PhD candidates, and professionals in diverse scientific and engineering communities devoted to relevant fields, including textile engineering, chemistry, bioengineering, material engineering, mechanical engineering, electrical engineering. The book will also provide a solid reference for industrial players who look for innovative technologies as well as environmental, safety concerns for the development of smart textile related products

Handbook of smart textiles

Preface 1 Sensor Definitions and Conventions 11 Is It a Sensor or a Transducer? 12 Position versus Displacement 13 Absolute or Incremental Reading 14 Contact or Contactless Sensing and Actuation 15 Linear and Angular Configurations 16 Application versus Sensor Technology 2 Specifications 21 About Position Sensor Specifications 22 Measuring Range 23 Zero and Span 24 Repeatability 25 Nonlinearity 26 Hysteresis 27 Calibrated Accuracy 28 Drift 29 What Does All This about Accuracy Mean to Me? 210 Temperature Effects 211 Response Time 212 Output Types 213 Shock and Vibration 214 EMI/EMC 215 Power Requirements 216 Intrinsic Safety, Explosion Proofing, and Purging 217 Reliability 3 Resistive Sensing 31 Resistive Position Transducers 32 Resistance 33 History of Resistive Linear Position Transducers 34 Linear Position Transducer Design 35 Resistive Element 36 Wiper 37 Linear Mechanics 38 Signal Conditioning 39 Advantages and Disadvantages 310 Performance Specifications 311 Typical Performance Specifications and Applications 4 Capacitive Sensing 41 Capacitive Position Transducers 42 Capacitance 43 Dielectric Constant 44 History of Capacitive Sensors 45 Capacitive Position Transducer Design 46 Electronic Circuits for Capacitive Transducers 47 Guard Electrodes 48 EMI/RFI 49 Typical Performance Specifications and Applications 5 Inductive Sensing 51 Inductive Position Transducers 52 Inductance 53 Permeability 54 History of Inductive Sensors 55 Inductive Position Transducer Design 56 Coil 57 Core 58 Signal Conditioning 59 Advantages 510 Typical Performance Specifications and Applications 6 The LVDT 61 LVDT Position Transducers 62 History of the LVDT 63 LVDT Position Transducer Design 64 Coils 65 Core 66 Carrier Frequency 67 Demodulation 68 Signal Conditioning 69 Advantages 610 Typical Performance Specifications and Applications 7 The Hall Effect 71 Hall Effect Transducers 72 The Hall Effect 73 History of the Hall Effect 74 Hall Effect Position Transducer Design 75 Hall Effect Element 76 Electronics 77 Linear Arrays 78 Advantages 79 Typical Performance Specifications and Applications 8 Magnetoresistive Sensing 81 Magnetoresistive Transducers 82 Magnetoresistance 83 History of Magnetoresistive Sensors 84 Magnetoresistive Position Transducer Design 85 Magnetoresistive Element 86 Linear Arrays 87 Electronics 88 Advantages 89 Typical Performance Specifications and Applications 9 Magnetostrictive Sensing 91 Magnetostrictive Transducers 92 Magnetostriction 93 History of Magnetostrictive Sensors 94 Magnetostrictive Position Transducer Design 95 Waveguide 96 Position Magnet 97 Pickup Devices 98 Damp 99 Electronics 910 Advantages 911 Typical Performance Specifications 912 Application 10 Encoders 101 Linear Encoders 102 History of Encoders 103 Construction 104 Absolute versus Incremental Encoders 105 Optical Encoders 106 Magnetic Encoders 107 Quadrature 108 Binary versus Gray Code 109 Electronics 1010 Advantages 1011 Typical Performance Specification and Applications References Index

David S. Nyce

Papers

Linear position sensors : theory and application

Linear position sensors