Sensors for Mechatronics

Transcription

1 Sensors for Mechatronics Paul P.L Regtien Hertgelo The Netherlands AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK' OXFORD ELSEVIER PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO

2 Contents Preface xi 1 Introduction Sensors in Mechatronics Definitions Sensor Development Sensor Nomenclature Sensors and Information Selection of Sensors 13 2 Sensor Fundamentals Physical Quantities Classification of Quantities Relations Between Quantities Sensor Classifications Classification Based on Measurand and Application Field Classification Based on Port Models Classification Based on Conversion Principles Classification According to Energy Domain 31 3 Uncertainty Aspects Sensor Specification Sensitivity Non-linearity and Hysteresis Resolution Accuracy Offset and Zero Drift Noise Response Time Frequency Response and Bandwidth Operating Conditions Sensor Error Reduction Techniques Compensation Feedback Methods Filtering Modulation Demodulation Correction Methods 53

3 vi Contents 4 Resistive Sensors Resistivity and Resistance Potentiometric Sensors Construction and General Properties Electrical Characteristics Interfacing Contact-Free Potentiometers Applications of Potentiometers Strain Gauges Construction and Properties Interfacing Applications of Strain Gauges Piezoresistive Sensors Piezoresistivity Micromachined Piezoresistive Sensors Applications of Piezoresistive Sensors Magnetoresistive Sensors Magnetoresistivity Applications of Magnetoresistive Sensors Thermoresistive Sensors Thermoresistivity Resistance Thermometer Thermistors Optoresistive Sensors 95 5 Capacitive Sensors Capacitance and Permittivity Basic Configurations of Capacitive Sensors Flat-Plate Capacitive Sensors Multiplate Capacitive Sensors Silicon Capacitive Sensors Interfacing Applications Capacitive Sensors for Position-and Force-Related Quantities Particular Applications Inductive and Magnetic Sensors Magnetic and Electromagnetic Quantities Magnetic Field Strength, Magnetic Induction and Flux Permeability Eddy Currents Magnetic Resistance (Reluctance) and Self-Inductance Magnetostriction 129

4 Contents vii 6.2 Magnetic Field Sensors Coil Hall Plate Sensors Fluxgate Sensors Magnetic and Induction Based Displacement and Force Sensors Magnetic Proximity Switches Inductive Proximity and Displacement Sensors Eddy Current Displacement Sensors Variable Differential Transformers Resolvers and Synchros Magnetostrictive or Elastomagnetic Sensors Applications Interfacing Inductive Sensors Contact-Free Sensing Using Magnetic and Inductive Sensors Applications of Variable Reluctance and Eddy Current Sensors Applications of Other Inductive Sensors Optical Sensors Electro-Optical Components Light Emitters Light Sensors Position Sensitive Diode Optical Displacement Sensors Intensity Measurement Triangulation Optical Encoders Interferometry Time-of-Flight Interfacing LEDs and Photo Diodes Interfacing PSDs Applications Linear Displacement Sensing Angular Displacement Sensing Object Tracking Object Shape Navigation Force, Torque and Strain Sensing Piezoelectric Sensors Piezoelectricity Piezoelectric Materials Piezoelectric Parameters 221

5 viii Contents 8.2 Force, Pressure and Acceleration Sensors Construction Characteristics of Accelerometers Interfacing Applications Stress and Pressure Acceleration Tactile Sensors Acoustic Sensors Properties of the Acoustic Medium Sound Intensity and Pressure Sound Propagation Speed Acoustic Damping Acoustic Impedance Acoustic Sensors General Properties Electrostatic Transducers Piezoelectric Transducers Arrays Measurement Methods Burst Continuous Sine Wave (CW) Frequency-Modulated Continuous Waves (FMCW) Other Signal Types Applications Navigation Inspection 264 Appendix A Symbols and Notations 275 A.1 The Electrical Domain 275 A.2 The Thermal Domain 277 A.3 The Mechanical Domain 277 A.4 The Optical Domain 280 A.4.1 Optical Quantities 280 A.4.2 Radiant Energy from a Unit Surface with Lambertian Emission 283 A.4.3 Derivation of Relations Between Intensity and Distance 284 Appendix B Relations Between Quantities 287 B. l Generalized Equations 287 B.2 Application to Four Domains 289 B.3 Heckmann Diagrams 292

6 Contents ix Appendix C Basic Interface Circuits 295 C.l Operational Amplifier 295 C.2 Current-to-Voltage Converter 297 C.3 Non-Inverting Amplifier 298 C.4 Inverting Amplifier 300 C.5 Comparator and Schmitttrigger 301 C.5.1 Comparator 301 C.5.2 Schmitttrigger 302 C.6 Integrator and Differentiator 303 C.6.1 Integrator 304 C.6.2 Differentiator 304 C.7 Filters 307