curves and surfaces representation and application
DESCRIPTION
Lecture given at the University of Windsor on 11 August 2011.TRANSCRIPT
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Curves and SurfacesRepresentation, and Applications
Diaa F. ElKott, Ph.D.
Carl Zeiss Industrial MetrologyBrighton, Michigan
August 11, 2011
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
VitaeDiaa ElKott
Work: Software Engineer, Carl Zeiss Industrial Metrology.
� Development of coordinate metrology software componentsa.
� Research of sculptured surfaces measurement methods.
Education:
� B.Sc., Production Engineering - Mansoura University.
� M.A.Sc., Industrial Engineering - University of Windsor.
� Ph.D., Mechanical Engineering - McMaster University.
aExamples: offline simulation of the measurement process, blade section re-sampling.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
A Math Tale
The Problem
Once upon a time, at a school in Germany, the teacher askedhis pupils to calculate:∑
81297 + 81495 + 81693. . . + 100701 + 100899
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
A Math Tale
The solution
Solution by Carl Friederich Gaussa
A =∑
81297 + 81495 + 81693. . . + 100701 + 100899
Ar =∑
100899 + 100701 + . . . + 81693 + 81495 + 81297
ai + ar i = 182196
A = ( ai+ar i2
)× 100
Final answer:
A = ( 81297+1008992
) × 100
A = ( 1821962
) × 100 = 91098 × 100 = 9109800.
aCarl Gauss was 10 years old when he solved this problem!
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureSculptured vs primitive surfaces
Part with primitive surfaces Part with sculptured surfaces
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process
The Manufacturing Process
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process
The Manufacturing Process
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
ErrorsErrorsErrorsErrors
ErrorsErrors
ErrorsErrors ErrorsErrors
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process
The Manufacturing Process
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
CADCADCADCAD
CADCAD
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
BackgroundTheory, and experience.
“Experience without theory is blind, but theory withoutexperience is mere intellectual play”.
Immanuel Kant (1724 1804)
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
I. Curve and Surface Representation Methods
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesPoints
Points
A point is a 0-dimensional mathematical object. A point is the buildingelement of higher-dimensional geometric objects (line, plane, etc.)
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesPoints
Two-Dimensional Cartesian Coordinate System
x
y
Origin
A coordinate system is a system which is used to define the location of apoint uniquely with respect to a point of origin.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesPoints
Cartesian Coordinates of Co-Planar Points
x
y
(5,4)
(-3,-3)
Origin
A coordinate system is a system which is used to define the location of apoint uniquely with respect to a point of origin.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Definition of a Curve - 1
x
y
A curve is the path of a point in motion.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Definition of a Curve - 2
Curve
x
y
A curve is the path of a point in motion.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Definition of a Curve - 3
Curve equation
x
y
A curve is the path of a point in motion.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Mathematical Representation of Curves
F ( x , y )=Constant
x
y
Implicit curve equation.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Mathematical Representation of Curves
y=F ( x)
x
y
Explicit curve equation.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Mathematical Representation of Curves
x=x (u)y= y (u)u1⩽u⩽u2
x
y
Parametric curve representation.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Curve Properties - 1
t⃗ in⃗i
p i
xi
y i
x
y
Tangent, and normal vectors of planar curve at point pi .
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane Curves
Curve Properties - 2
t⃗ in⃗i
p i
xi
y i
x
y
r i
Osculatingcircle
Osculating circle of planar curve at point pi . Curve curvature, κi = 1.0ri
.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
y
(x i , y i)
A circle is the path of a point that moves such that it is at a constantdistance from a given co-planar point.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
y
r y i
x i
r=√ x i2+ y i2
A circle is the path of a point that moves such that it is at a constantdistance from a given co-planar point.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
y
x2+ y2=r 2
Implicit equation of a circle.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
y
y=±√r2−x2
Explicit equation of a circle.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
y
ry i
x i
cos (θi)=x ir
sin(θi)=y ir
θ i
Derivation of parametric representation.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Plane CurvesMathematical representation of a circle
The Circle
x
yx=r cos (θ)y=r sin (θ)0⩽θ⩽2π
θ
Parametric representation.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Space CurvesRepresentation, and important properties.
Space Curve
Space curve
x=x (u)y= y (u)z=z (u)u1⩽u⩽u2
( x(ui) , y (ui) , z(ui))
x
y
z
A space curve is the path of a 3-dimensional point in motion.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Space CurvesRepresentation, and important properties.
Space Curve
Space curve
x=x (u)y= y (u)z=z (u)u1⩽u⩽u2
( x(ui) , y (ui) , z(ui))
x
y
z
uu1 u2u i
Mapping from the parametric space to the Cartesian space.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Space CurvesRepresentation, and important properties.
Space Curve
Space curve
t⃗ i
n⃗i
p i=C (ui)
b⃗i
x
y
z
C (u)
Tangent, principal normal, and binormal vectors at point pi.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Space CurvesRepresentation, and important properties.
Space Curve
Space curve
t⃗ i
n⃗i
b⃗i
Osculatingplane
Normal plane
Rectifying plane
p i=C (ui)
x
y
z
C (u)
Moving trihedron (Frenet Frame) of space curve.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
SurfacesRepresentation, and important properties.
Parametric Representation of Surfaces
x
y
z
x=x (u , v )y= y (u , v)z=z (u , v)
u1⩽u⩽u2v1⩽v⩽v2
Surface( x(ui , v j) , y (ui , v j ) , z (ui , v j ))
A surface is a subset of R3 that looks like a piece of R2 in the vicinity ofany given point.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
SurfacesRepresentation, and important properties.
Parametric Representation of Surfaces
x
y
z
Surface( x(ui , v j) , y (ui , v j ) , z (ui , v j ))
Isoparametriclines v
uu1 u2u i
v1
v2
v j
x=x (u , v )y= y (u , v)z=z (u , v)
u1⩽u⩽u2v1⩽v⩽v2
Mapping from the parametric space to the Cartesian space.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
SurfacesRepresentation, and important properties.
Parametric Representation of Surfaces
x
y
z
Surface
S (u , v)
p i , j=S (ui , v j)n⃗i , j Sui , j
S v i , j
Tangentplane
Tangent plane, and normal vector at point pi,j.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
II. Application of Curve and Surface Methods
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
BackgroundTheory, and experience.
“Experience without theory is blind, but theory withoutexperience is mere intellectual play”.
Immanuel Kant (1724 1804)
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process, revisited
The Manufacturing Process
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process, revisited
The Manufacturing Process - Inspection
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
ManufactureThe manufacturing process, revisited
The Manufacturing Process - Inspection Feedback
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
Design Process
●Conceptual design.●FEA.●Assembly design.●Design for manufacture.....
GenerateMachining
Instructions(CAM)
GenerateMachining
Instructions(CAM)
ManufacturePart(CNC)
ManufacturePart(CNC)
Design Intent
Material Requirement
Design Constraints
CAD Model(with tolerances)
CAD Model(with tolerances)
Physical Object(with manufacturing errors)
Physical Object(with manufacturing errors)
Inspection Planning
●Where to measure.●Sample size.....
Inspection Planning
●Where to measure.●Sample size.....
MeasurePart(CMM)
MeasurePart(CMM)
AnalyseMeasurement
Results
AnalyseMeasurement
Results
AcceptAcceptRejectReject
Feedback
Feedback
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
MetrologyThe science of measurement
Metrology
Metrology is derived from the Greek words: Metron -Measure, and Logos - calculation, study, reason.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
MetrologyThe science of measurement
Metrology
Metrology is derived from the Greek words: Metron -Measure, and Logos - calculation, study, reason.
Metrology is the science of measurement.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
MetrologyThe science of measurement
Coordinate Metrology
Coordinate metrology is concerned with measuring the spatialcoordinates, mostly of physical objects.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
The Coordinate Measuring Machine
The CMM is a Cartesian robot which is utilised to measure the coordinatesof surface points.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
The Coordinate Measuring Machine Sensor
The CMM is a Cartesian robot which is utilised to measure the coordinatesof surface points.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Coordinate Measurement
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Coordinate Measurement
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Micro-Measuring Technology
Micro-measuring using hybrid sensors.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Micro-Measuring Technology
TactileSensor
OpticalSensor
Workpiece
Micro-measuring using hybrid sensors.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Micro-Measuring Technology
Micro-measuring using hybrid sensors.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyMeasuring physical objects
Micro-Measuring Technology
Micro-components
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyChallenge
Measurement Inspection
CAD geometry
Upper tolerance limit
Lower tolerance limit
Physical model
Test conformity of the geometry of physical model to the design intent.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyChallenge
The Inspection Process, Revisited
Inspection ProcessInspection Process
CAD Model
Physical Object
AcceptAccept
RejectReject
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyChallenge
The Inspection Process - Sources of Error
Inspection ProcessInspection Process
CAD Model
Physical Object
AcceptAccept
RejectReject
AlgorithmicErrors
SoftwareErrors
HardwareErrors
HumanErrors
The inspection process is influenced by several sources of error.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Coordinate MetrologyChallenge
Measurement Uncertainty
x
y
z
ϵTrue point(unknown)
Measured point
Measurement Uncertainty
Uncertainty cloud - all the possible readings of a particular point.
The form, and size of the uncertainty cloud may vary with time.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyProbing direction
Effect of Probing Direction
rcp
n
probe
workpiece
probing in surface normal direction
p
(a) Correct contact point, p = cp +r ×~n
rcp
n '
probe
workpiece
probing in vertical direction
pp '
(b) Erroneous contact point, p′ =cp + r ×~n′
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyProbing direction
Turbine Blade Measurement Path
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyProbing direction
Turbine Blade Measurement Path
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyMeasurement Path
Measurement path
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyMeasurement Path
Measurement path
Use the CAD geometry to define the CMM measurement path.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyData localisation
The Problem - 1
xCAD
yCAD
zCADCAD model
Nominalmeasurementpoints
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyData localisation
The Problem - 2
xCAD
yCAD
zCADCAD model
Nominalmeasurementpoints
xActual
yActual
zActual
Physical model Actualmeasurementpoints
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyData localisation
Problem formulation
Align scanned data points P with the CAD model of the physical objectsuch that:
P = {P0, . . . ,Pn−1}Pi = {pi
0, . . . , pimi−1}
using the objective function:
MinimizeFunction
1n−1∑i=0
mi
×∑∀pl∈P
d2l
dl = GetShortestDistance(S,R× pl + T)
pnewl =
xnewl
ynewl
znewl
= R(O, θx)×R(O, θy )×R(O, θz)×
xoldl
y oldl
zoldl
+
δxδyδz
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyData localisation
Example
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyDeviation calculation
Solid Model, and Physical Object
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Application of Geometry in Coordinate MetrologyDeviation calculation
Measurement Data, Object Assessment Results
0.080 mm
0.030 mm
0.005 mm
0.000 mm
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Summary
Summary
1 Geometric elements are utilised to represent physical objects virtually.
2 The mathematical representation of geometric elements is utilised tocalculate important properties of the physical objects.
3 The properties of the physical objects’ geometry are utilised in thedesign, analysis, manufacture, and measurement of the physicalobjects.
Curves andSurfaces
D. ElKott
PREAMBLE
MATH TALE
MANUFACTURE
CURVES &SURFACES
Curves
Surfaces
APPLICATION
Manufacture
Metrology
Inspection
SUMMARY
Summary
“Experience without theory is blind, but theory withoutexperience is mere intellectual play”.
Immanuel Kant (1724 1804)