Design and Analysis of Kinematic Couplings for Modular Machine ...

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Wireless Close Read ORDirect Entry- Ethernet -SERIAL #(Direct/Code/RFID)INTERFACE/MODULECONTROL CABINETDATABASE SERVERCalibration DataFigure 1.2: Schematic of an intelligent kinematic interface.The most apparent application of standardization is to robotics, for which the standards could enable arobotic subassembly, such as a wrist, to be easily changed, without requiring recalibration of the robot. Thewrist would mate to a standard plate. A similar master plate would be located at the robot manufacturer,and each subassembly would be calibrated with respect to the mounting plate master. Thus when a replacementsubassembly is delivered to the factory, it comes with a set of calibration coefficients with respect tothe mounting plate master, and it can be “plugged into place and start working”. Thus should a subassemblyfail during use, it could be “unplugged” and a new subassembly could be “plugged in” and used withouthaving to recalibrate it to the line.1.3 Thesis OutlineThis thesis focuses on application of kinematic couplings to enable high-precision modularity of factoryautomation, with two focus applications: the factory interface of a heavy-duty-industrial robot usedfor automotive body assembly, and the structure of a next-generation microscope to be used for singlemoleculebiological investigations. This document is organized as follows:16
Chapter 2 is an overview of the basic principles of kinematic coupling design and Hertzian contactmechanics. These principles are applied to present design methodologies for traditional ball/groove, canoe ball/groove, three-pin, groove/cylinder, and quasi-kinematic couplings.Chapter 3 presents and validates a deterministic model for assessing the interchangeability error ofkinematic interfaces caused by assembly variation and form error in the coupling units and interfacemounting plates. The model is presented in detail as an exact solution for canoe ball couplings,and is extended with deterministic mating assumptions to the three-pin interface.Chapter 4 presents an application case study of canoe ball, three-pin, and groove-cylinder couplingsto the factory interface of the ABB IRB6400R industrial robot manipulator. Results of staticand dynamic repeatability measurements are presented, and the interchangeability of the canoeball and three-pin designs is simulated using the model described in Chapter 3.Chapter 5 presents the structural design of a modular high-precision microscope as a series of tubesegments connected by canoe ball kinematic couplings. Experimental study and design optimizationusing finite element simulation show that the segmented design offers a significant thermalstability advantage over a one-piece tubular structure, and the known high repeatability of thekinematic couplings enables the structural modules to be interchanged without recalibration of theoptics.Chapter 6 presents a framework for large-scale implementation of kinematic couplings in a modularmanufacturing system. Three developments would be critical: standardization of the kinematiccoupling design process through a set of input and output parameters specific to each interface;design of low-cost locators with smart methods to hold interchangeability calibration parameterdata; and integration of the interfaces into a networked system to enable ‘plug-and-play’ authenticationof interfaced parts or carriers and feedback of process performance data.17
Page 1: Design and Analysis of Kinematic Co
Page 4 and 5: kinematic couplings. Most powerfull
Page 6 and 7: 6. Toward Standard, Low-Cost, Intel
Page 8 and 9: Chapter 44.1 Six-axis industrial ro
Page 10 and 11: Chapter 66.1 Parameter heirarchy fo
Page 13 and 14: Chapter 1Introduction1.1 Motivation
Page 15: 2. How can the deterministic nature
Page 20 and 21: Figure 2.1: Model of three-ball/thr
Page 22 and 23: For a case study of a simple symmet
Page 24 and 25: contacting space all the way around
Page 26 and 27: 2.2 Canoe Ball CouplingsThe main ca
Page 28 and 29: strength materials) and create a so
Page 30 and 31: ⎧112 ⎛ ⎛ ⎛ --δ ⎛f n ---
Page 32 and 33: F 11 sin( α)- sin( β)0 0 0- 1 D -
Page 34 and 35: contact, and translation of the ass
Page 36 and 37: K1--2⎛3F⎝------⎞ 1= ⎛2 ⎠
Page 39 and 40: Chapter 3Interchangeability of Dete
Page 41 and 42: coordinate frame by a translation a
Page 43 and 44: in translation error normal to the
Page 45 and 46: MeasurementErrorT measerrorInterfac
Page 47 and 48: interfaces can approach their indiv
Page 49 and 50: Figure 3.5: Canoe ball mount with i
Page 51 and 52: they directly become the rows of th
Page 53 and 54: δ xcδ ycε interchange=δ zc(3.19
Page 55 and 56: 2. p Sn,1 , p Sn,2 , etc. = Relativ
Page 57 and 58: parameters are directly the points
Page 59 and 60: nominal thickness, and the magnitud
Page 61 and 62: y measy measy ballyy ballzyFigure 3
Page 63 and 64: The angular alignment of the groove
Page 65 and 66: while the couplings and measurement
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Complexity Example Calibration Proc
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Error Component [units]Valueh tol [
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0.20Tool Point Error [mm]0.150.100.
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Figure 3.14: Prototype groove base
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Figure 3.17: Interchangeability set
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0.00450.00400.0035MeasuredAfter Exc
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3.7.1 Variable DimensionsThe interc
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This model is used in the next chap
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appropriate calibration procedures
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Chapter 4Machine Case Study: Mechan
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ures empirically cause a per shift
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4.2 Current Interface Design and Ro
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4.2.2 Current Robot Calibration Pro
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ally demanded for continuous path a
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In the canoe ball case, design a pr
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unseating, reseating, and measuring
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Although dynamic tests were not run
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For the first step, the coupling lo
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Figure 4.16: Interface plates fitte
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Figure 4.18: Prototype shouldered c
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Knowing 50 N-m of torque would be a
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constraint, then applying a preload
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4.5 Prototype Repeatability TestsWi
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Two test procedures were establishe
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For the basic mounting procedure, s
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torque was more than sufficient to
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The measurements of static quasi-ki
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neighborhood) trial to the outlying
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Deviation [mm]0.200.150.100.050.00-
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Figure 4.44: Canoe ball surface aft
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4.6.1.2 ResultsTable 4.9: Error com
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the accuracy of the base interface
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interface produces perfect intercha
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0.20Tool Point Error [mm]0.180.160.
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Figure 4.49: Split groove canoe bal
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Generally, the concept of a determi
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20 C) and dirt buildup and harsh tr
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Chapter 5Instrumentation Case Study
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that many of them may be used simul
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diameter, with equilaterally triang
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Figure 5.4: Theorized constant temp
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Therefore, with the goal to minimiz
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All heat transfer relations are ref
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Angular drift of the stack was meas
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knowledge of the resistance across
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4. After these six hours of heating
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5.3.3 Results5.3.3.1 Finite Element
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Figure 5.15: Axial displacement con
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0.200.10Tilt Angle [arcsec]0.00-0.1
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superior in disturbance rejection,
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1.801.601.40Temperature [C]1.201.00
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Temperature [C]1.801.601.401.201.00
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0.2000.150Temperature [C]0.1000.050
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of heat, the temperature difference
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0.200 50 100 150 200 250 300 350 40
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Table 5.3 gives the results of the
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0.350.3One-Piece5 Segments1-9 Segme
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copper tube segments. Individual 1W
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Fixed-base parallel manipulators ca
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Chapter 6Toward Standard, Low-Cost,
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The efficiency of the standard mech
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6.1.2 Building and Using a Web-Base
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tor, offers similar design guidance
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other unit can be homogeneous with
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dcontactRcoupLtRoutRinθFigure 6.4:
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parallel arrangement of springs for
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Wireless Close Read ORDirect Entry-
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matted as XML schemas and broadcast
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PROCESS FEEDBACKSYSTEMADMINISTRATOR
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Furthermore, a fourth class of inte
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For datum point (rather than custom
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OFFLINECOMPUTERInteractive display
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Chapter 7ConclusionThis thesis soug
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Appendix AReferencesChapter 2[1] Sl
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Appendix BKinematic Coupling Design
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MLz + FLy*XL - FLx*XL];% Coupling D
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end% Computation of coupling locati
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ctthree = Rethree*sqrt((1/Rgrv3)^2+
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% New ball coordinatesxboneN = xbon
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four))^2)*sign(Abc*delthree+Abd*del
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B.2 Contact Force Calculation for T
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Rpins = 0.5;yo = 0.5;% radius offse
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f2_torquevector = mut*cross(v_fr2_c
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n3_torquevector = cross(v_cont3,v3_
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Appendix CKinematic Exchangeability
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tol_msys = 0.1; % measurement syste
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% Nominal groove normal vectorsn11
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pvr_grooves = randn(3,1).*pt_ps;pvt
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a21b = -1*sin(th2b)/sqrt(1+tan(thg)
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32gt = -cos(th3g)/sqrt(1+tan(thga3_
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% 14 = using offset measurement fea
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function [errorHTM] = errortransfor
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% of a three-pin kinematic coupling
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mag(normal1)*radii(1) + normal1(1)*
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Appendix DAppended Thermal Stabilit
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Temperature [C]0.800.700.600.500.40
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Temperature [C]0.800.700.600.500.40
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Appendix ERobot Calibration Pose Se
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