1Motion and dimensional measurement

By

Aj. Somchai Triratanajaru M.Eng. KMUTT,

B.EngKMITL

Term 1/2553

2LECTURE OUTLINE

1. Standards and Calibration 2. Relative Displacement: translational and

rotational 3. Relative Velocity: translational and rotational 4. Relative Acceleration Measurements 5. Seismic-(Absolute-)Displacement Pickups 6. Seismic-(Absolute-)Velocity Pickups 7. Calibration of Vibration Pickups 8. Jerk Pickups 9. Angular-Displacement Sensors

3LECTURE OUTLINE

10. Coordinate-Measuring Machines 11. Surface-Finish Measurement 12. Machine Vision 13. The Global-Positioning

*Major part of this presentation are from Measurement Systems, Ernest O. Doebelin

41.Standards and calibration

Fundamental standard.Length standards-> wavelength of kypton-86.(fundamental standard, ultimate standard)Atomic clock-> atomic resonators cesium-133 Calibration.For application standards (engineeringapplicable) will be inform in each section.

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Relative displacement : Translational and Rotational

Calibration-Static calibration via micrometers 0.01 mm

gage blocks 12 micro-mlaser interferometer 0.6 nm

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Transducer applications of displacement (basic for the others variable)

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Resistive Potentiometers (single-turn, multi-turn, linear and rotating translation)

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Potentiometer loading effect (Linearity, power loss)

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Construction of wire-wound resistance (resolution)

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Conductive-plastic potentiometer.

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Magneto-resistive displacement transducer.

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Un-bonded strain gage (metal)

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Metal wire under extension force

A A-dA

L L+dL

F F

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Resistance Strain Gage.

R=L/A -> dR=(A(dL+Ld)- LdA)/A2 (a)V=AL -> dV=AdL + LdA (b)Also, (from static engineering)dV = L(1+)A(1- )2 AL (c):unit strain, : Poissons ratio. And, (from numerical approximation) when is small, (1- )2 -> 1- 2, (b)=(c)dV = AL(1-2) = AdL + LdA

-2AdL= LdA

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Resistance Strain Gage..

dR=(AdL+LAd + 2AdL)/A2

dR=(dL(1+2))/A + (Ld)/AdR/R = (dL/L)(1+2) + d/

Gage factor or GF -> (dR/R)/(dL/L)= 1 + 2 + (d/)/(dL/L)(a:) (b:) (c:)

a: R change due to length changeb: R change due to area changec: R change due to piezo-resistance effect(GF is + with metal with semi-conductor)

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Resistance Strain Gage

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Resistance Strain Gage.

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Resistance Strain Gage..

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Foil strain gages

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Foil strain gages..

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Foil strain gages

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Strain-gage rosettes

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SG Signal conditioning

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Strain-gage temperature compensation

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Stability of SG

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SG displacement transducers and extensometer

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Extensometer analysis

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Weld able strain gage

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Differential Transformers

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Methods for Null Reduction

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Demodulation & Filtering.

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Demodulation & Filtering..

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Demodulation & Filtering

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LVDT: Signal Conditioning

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Industrial type LVDT

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LVDT Application

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Application..

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Application

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Application.

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Inside LVDT

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Inside LVDT..

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Inside LVDT

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Real LVDT

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Small LVDT

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Integrated electronics

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On-board LVDT

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AC Servomechanism

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Synchos

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Resolver and digital converter

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Variable-inductance pickup

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Variable inductance accelerometer

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Micro-Syn

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Eddy current non-contact transducers

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Target-Material Effect on Eddy-Current Transducer

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Capacitance Pickups

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Frequency Response of Capacitive Sensor

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Differential-Capacitor Pressure Pickup

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Feedback-Type Capacitive Pickup

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Feedback-Type Capacitive Pickup..

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Capacitive Pickup: Signal Processing

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Capacitive Pickup: Signal Processing..

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Piezoelectric Transducer

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Piezoelectric Transducer

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Piezoelectric Transducer..

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Three-Component Piezoelectric Force Transducer

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Fiber-Optic Displacement Transducer

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Laser Dimensional Gauge

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Michelson Interferometer

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Self-Scanning Diode Arrays and Cameras

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Homographic

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Homographic..

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Nozzle Flapper

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Nozzle Flapper..

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Translational and Rotary Encoders

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Schematic diagram

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Translational and Rotary Encoders..

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Disk image form

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Translational and Rotary Encoders..

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Translational and Rotary Encoders

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Output wave form of incremental encoder

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Linear encoder (open type)

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Linear encoder (enclosure type)

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Resolution of Displacement Sensors

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Ultrasonic Displacement Transducer

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Velocity-Calibration Setup

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Average Velocity Measurement from x/t : Magnetic Pickup

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Average Velocity Measurement from x/t : Photodetectors

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Average Velocity Measurement from x/t : Hall-Effect Proximity Pickup

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Fly-ball Angular-Velocity Sensor

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Moving-Coil and Moving-Magnet Velocity Pickup

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Moving-Coil and Moving-Magnet Velocity Pickup..

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Tachometer Generators

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Drag-Cup Velocity Pickup

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Translational and Rotational Seismic Pickups

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Coordinate-Measuring Machines

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Touch Probe

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Surface-Finish Measurement

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Optical Surface-Finish Measurement

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Machine Vision: Applications and Features

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Light sheet Applications

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Integration of Machine Vision into Manufacturing System

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Further reading and more exercises

Text.Process control Instrumentationtechnology

Curtis D. Johson