TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 1
TMT M1 Segment Support Assembly (SSA) Preliminary Design Review (PDR)
Volume-1: OVERVIEW
Pasadena, CaliforniaOctober 24-25, 2007
Contributors to the development effort:from IMTEC
RJ Ponchione, Eric Ponslet, Shahriar Setoodeh, Vince Stephens, Alan Tubb, Eric Williams
from the TMT ProjectGeorge Angeli, Curt Baffes, Doug MacMynowski, Terry Mast, Jerry Nelson, Ben
Platt, Lennon Rodgers, Mark Sirota, Gary Sanders, Larry Stepp, Kei Szeto
TMT ConfidentialThe Information herein contains Cost Estimates and Business Strategies Proprietary to the TMT Project and may be
used by the recipient only for the purpose of performing a confidential internal review of the TMT Construction Proposal. Disclosure outside of the TMT Project and its External Advisory Panel is subject to the prior written approval
of the TMT Project Manager.
* Note: HYTEC, Inc. merged with IMTEC Inc. in March 2007.
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 2
OutlineVolume-1: Overview
– Thirty Meter Telescope Overview– SSA Project Overview– Key Design Requirements– Design Concept– SSA Preliminary Design
Key Subsystems– Axial Support– Lateral Support– Tower, Guide Flexure, Locks, Registration– Warping Harness– Subcell
Volume-2: System Level Calculations– M1 Segmentation – Segmentation Correction (for Variable Segment Geometry)– Budgets:
Installation & Alignment
Edge Gap
Actuator Stroke
Mass
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 3
OutlineVolume-3: System-Level Finite Element Analysis
– Model Description– Optical Performance– Stiffness and Modes– Buckling– Sensitivity Analyses– Stress Analysis– Backup Slides
Volume-4: Warping Harness Design and Analysis– Fundamental Approach & Architecture– Warping Harness Requirements
Opto-mechanicalMechanical
– Design Concept– Performance Analysis
Actuator arrangementSurface correction
– Derived Requirements for Components– Mechanical & Electrical Design– Quantization Error Estimate
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 4
OutlineVolume-5: Flexure Design and Analysis
– Design Load Combinations– Central Diaphragm– Rod-Type Flexures– Lateral Guide Flexure
Volume-6: Subcell Integration & Segment Handling– Subcell Integration & Alignment
Fixed Frame InstallationDummy MassSubcell Alignment
– Segment Lifting Jack & Lifting TalonJack design Lifting Talon design
Volume-7: Summary and Future Plans– Prototype Testing
Test Plans– Component testing– Full Prototype testing
– Schedule– Summary
Where we are and where we’re goingTechnical Risks
– Conclusions
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 5
BRIEF TELESCOPE OVERVIEW
Thirty Meter Telescope
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 6
M1 Array30m Diameter
~60m ROC
492 Segments– 1.44m x 45mm1
Note 1) 45mm for Glass-Ceramic, 50mm for Fused Silica
PSA On Mirror Cell
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 7
Segment SizeNominal Segment size is 1.44 m across vertices
– Limited by blank size to maintain several competitive suppliers
Thickness:– 45 mm if glass ceramic– 50 mm if fused silica (ULE)
Aperture limits:– Outermost corners: 15.0 m radius– Innermost corners: 1.45 m radius
1.44
15.0
1.45
30m diameter
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 8
M1 ParametersFundamental M1 Parameters:– Constant-gap segmentation:
82 different segment shapes
Six identical sectors
– Nominal segment:1.44m regular hexagonal meniscus
Glass-Ceramic, 45mm thick
60m paraxial radius of curvature– Neglect asphericity in support design
activities
– Average segment ROC ~62.5m
Assume worst case CTE = -0.05 ppm/°C in analyses
– Alternate segment:Fused Silica, 50mm thick meniscus
SSA can be re-tuned to accommodate
XPSA
YPSA
ZPSA
YPSA
ZPSA
XPSA
ZPSA
YPSA
XPSA
SSA Base
Cell Truss
1.44 m
45 mm
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 9
M1 ParametersSegmentation Pattern:
Sector Boundary - Note Fixed Frame Clocking
60◦
View from Sky
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 10
SSA PROJECT OVERVIEW
Thirty Meter Telescope
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 11
SSA Project ScopeIMTEC Design/Development Responsibilities Include:– Segment Support Assembly (SSA)
– Segment Lifting Jack
– Segment Lifting TalonAttaches Mounted Segment Assembly (MSA) to Segment Handling Crane
– Subcell Integration Hardware:Mass Simulator
Surveying Target Holders
Subcell Alignment Tooling
– Release Prototype Drawings
– Build, Test and Deliver Prototypes
– Refine design for productionPropagate design to 82 versions (segmentation effects)
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 12
SSA Overview
Polished Mirror Assembly (PMA)
PolishedMirror
SegmentCentral Diaphragm (1 ea.)Moving Assembly (1 ea.)
--Whiffletrees (3 ea)--Moving Frame Assembly (1 ea)--Warping Harness Actuators (21 ea)--Lateral Guide Flexure (1 ea)--Tower Assembly (1 ea)--Lock Assemblies (3 ea)--Sheet Flexures (6 ea)
Electrical Bulkhead Panel Assembly
PRIMARY SEGMENT ASSEMBLY (PSA)
Segment Support
Fixed Frame Assembly (1 ea)
Adjustable Alignment Positioners (AAPs, 3 ea)
Actuator Flexure (3 ea)
Subcell
IMTEC Responsibility
IMTEC Responsibility
Comprises the SSARemoved for Re-coating
Mounted Segment Assembly (MSA)
Edge Sensors1
(6-drive, 6-sense)
Cables & Connectors for Sensor1 & WH
Optical Coating
Actuator1
1) In WBS, Actuator is part of the M1CS not M1Optics
Produced at Optics Shop
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 13
Primary Segment Assembly (PSA)Polished Mirror SegmentAdd Optical Coating, Edge Sensors, Sensor & WH Cabling & Connectors
Mounted Segment Assembly (MSA)Add Segment SupportPolished Mirror Assembly (PMA)Include Subcell + ActuatorsPSA ATTACHED TO MIRROR CELL
SSA Overview
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 14
SSA Overview
SEGMENT SUPPORT ASSEMBLY (SSA)
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 15
KEY DESIGN REQUIREMENTS
Requirements
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 16
Key Requirements (1/4)SSA-Induced Surface Errors:– Goal: Minimize gravity and thermal distortion while controlling cost– Optical performance of SSA evaluated by system level PSS analysis
Performed by Project and JPL using IMTEC unit case predictions as inputs– When complete, analysis to consider all SSA distortion effects:
Gravity, Thermal Distortion, Thermal Clocking, Polishing, Mfg, + …
Assumptions:– Observing segment-zenith angle: -15° to +80° → max Δς = 80°
0° to 65° telescope Zenith ± 15° from M1 curvature– Observing temperature: 9°C (TSITE) ± 4°C
Based on Armazones site testing data (80% of observing time within +/-4C)
Alignment & Phasing System (APS) + Warping Harness used regularly to null DC errors
- Seasonal mean temperature offset, Tmean
- Difference between optics shop figuring temp and Tref
Single Support-System design, customized for each segment type:– Accommodate shape variations from M1 segmentation (up to 0.5%)
No backlash or stick-slip:– Flexure-based mechanisms
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 17
Key Requirements (2/4)Accommodate ± 2.5mm actuator stroke: – SSA hard stops nominally at ±3.0mm– Survive full differential tip/tilt
Remote-controlled warping harness:– Control 2nd and 3rd order Zernikes:
Correction capability: 200 to 2100 nm P-V (38 to 410 nm RMS)Improvement ratio (RMS before correction / RMS after correction)
– > 15 on 2nd order terms: focus & astigmatism– > 5 on 3rd order terms: coma & trefoil
– Periodic Adjustment:Capability to readjust up to 10 times per night (~1/hour), if necessary
Power dissipation <2 Watts/segment– Includes all segment heat sources (Actuators, sensors, electronics, etc.)
50 years lifetime; high reliability:– Only significant wear items are warping harness moment actuators
6-DOF adjustable Subcell & repeatable registration system:– Correct for Mirror Cell tolerances ( ± 5 mm adjustment range, set-and-forget)– Removal/replacement of SSA with ± 50 μm repeatability
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 18
Key Requirements (3/4)SSA mass < 90 kg (moving mass < 45 kg)– Not including actuators, segment, edge sensors & cables for edge sensors
– Ref: Segment mass ~153 kg for glass ceramic
Static stiffness > 12 N/μm, piston:– Assuming rigid actuator & mirror cell
Natural frequencies of PSA > 35 Hz with 10N/m actuator stiffness:– Avoid rotating machinery disturbances at ~25 and ~30 Hz
50 or 60 Hz AC power grids possible
– Permit higher actuator control bandwidth
– EXCEPT:Torsional modes permitted to be <35 Hz
– Unlikely to be excited on telescope
– fn >8 Hz required for static stiffness
Environments:– Operating conditions such as temperatures, g-levels, etc
summary slide to follow
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 19
Key Requirements (4/4)MSA shall be compatible with Coating Chamber requirements TBC:– Cleanliness, Outgassing and Coating process compatibility
SSA design shall be designed for manufacture– 492 units + Spares allows for economies of scale if the design is sound
Maintainability and Servicing considerations– Segment exchanges are frequent and must be straightforward
Recoating every 2 years implies 5 segment exchanges per week on average
Cost control is fundamental to the design– Cost of manufacture and test
– Cost of ownershipReliability
Maintainability
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 20
Environments
1. About any axis in local x-ySSA plane2. In local zSSA direction (piston)3. SSA on telescope4. Scaled up from 1.2m segment loads by a2
5. Scaled up from 1.2m segment loads by a3
6. All dynamic loads treated as quasi-static. 1g dead weight not additional
Quantity Observing3 Non-obs.3 Survival3 Handling Transport Recoating
Segment Zenith angle1 (+Z to vert.)
0 to 80° 0 to 105° 0 to 105° 0 to 135° 0 to 135° 180°
Temp. and rate of change
0 ± 5°C
± 3°C/hr
-15 to 35°C -20 to 40°C -20 to 50°C -20 to 50°C ≤ 50 °C
Humidity 0 to 95% 0 to 100% 0 to 100% condensing
0 to 100% condensing
0 to 100% condensing
-
Wind force2 4.18N RMS
TBC4
4.18N RMS
TBC4
8.35N RMS
TBC4
8.35N RMS
TBC4
- -
Wind moment1 1.44Nm RMS
TBC5
1.44Nm RMS TBC5
2.88Nm RMS TBC5
2.88Nm RMS TBC5
- -
Quasi-static load6 1g 1.4g 3.0g, any axis
TBC
3.0g, any axis
TBC
10g, any axis
TBC
-
Altitude 2000-5000m 0-5000m 0-5000m 0-10000m 0-10000m 0-5000m
Tracking and slewing rates
El <0.039°/s
Az <2.26°/s
TBD TBD - - -
Tracking and slewing accel.
El <.00015°/s2
Az <.00880°/s2
TBD El <2.0°/s2
Az <2.0°/s2
TBC
- - -
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 21
DESIGN CONCEPT
SSA Design
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 22
Key Functions of SSASupport segment with minimum distortion (observation mode):
– Relative to reference state (as figured) ςSEG = 0°, TREF
Ability to position segment in 3 DOFs (piston, tip, tilt):– Continuous, active positioning by three linear actuators
Ability to alter surface shape to correct for figuring errors and other effects:– Occasional correction
Interface with Mirror CellProvide means to align SSA in 6 DOFs:
– Compensate for mirror cell fabrication tolerances (+/- 5mm any direction TBC]– One-time adjustment during telescope integration
Ability to remove and replace MSA with specified repeatability:– Quick replacement of segments without re-alignment of Subcell
Accommodate irregular/variable size segments with single support design:– Uniform gaps lead to irregular and/or variable size hexagons
Provide means to extract segment out of M1 array for re-coating/maintenance:
– Lifting jack – Segment Lifting Talon
Interface with segment removal crane
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 23
Diaphragm
Moving Frame
3 ea WhiffletreeGuide Flexure
Tower
Polished Mirror Segment
Axial Support Rod Flexures
Warping Harness Actuators, 21ea
Edge Sensors (12)
Mounted Segment Assembly (MSA)
Final FiguringCam Locks
(3ea)
Design Concept
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 24
3ea Actuators
3ea Adjustable Alignment Positioners (AAPs)
Fixed Frame
Mirror Cell
SUBCELL+ACTUATORS
Design Concept
ActuatorOutput Shaft
Actuatorflexure
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 25
MSA Placed on JackSegment Lifting Jack
Design Concept
Lifting Talon
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 26
MSA Attached to Subcell
Actuator FlexureClamped to
Moving Frame (3 places)
Design Concept
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 27
3ea Actuators
3ea Adjustable Cell Interface
Fixed FrameMirror Cell
Diaphragm3 ea WhiffletreeGuide Flexure
Mirror Segment
Axial Support Rod Flexures
Warping Harness Actuators, 21ea
Moving Frame
Tower
Cam Locks Released
PSA Operational Configuration
Design Concept
MSA hold-down bolts
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 28
PRELIMINARY DESIGN
SSA Design
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 29
Design StatusSegmentation scheme has been chosen:– Scaling rule selected to minimize blank diameter
We have a detailed 1.44m Preliminary Design:– 27-point mechanical whiffletree axial support
– Central diaphragm lateral support
– 21-actuator/segment, whiffletree-based warping harness
– Correction for segment shape variations via custom WT joint locations
– Repeatable interface, Subcell alignment, and actuator attachment
Extensive, coupled performance modeling has been performed:– Complete FEA revision to reflect Preliminary Design is complete
Design satisfies nearly all requirements
Completing final changes required for Prototype SSA fabrication
Hardware designs being detailed:– Detailed drawings for prototype in process
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 30
Current PSA DesignPSA attached to mirror cell:
Mirror Cell
Actuator
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 31
Flexures Bonded to Segment
Segment
Axial flexure assemblies27 ea. bonded to segment
Edge Sensor12 ea.
Central Diaphragm(bonded to segment)
Alignment ArrowPoints to center of M1
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 32
Small Whiffletree Triangles Attached
Small whiffletree triangle - 3 inner - 6 outer
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 33
Large Whiffletree Triangles Attached
Large whiffletree triangle
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 34
Sheet Flexures Added
Sheet flexure, 6eaIn-plane connection between Whiffletree
Triangles and Moving Frame
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 35
Moving Frame Attached
Moving frameSheet flexure, 6eaIn-plane connection between Whiffletree
Triangles and Moving Frame
V-Groove for lifting, 3 ea.
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 36
Warping Harness Added
Warping harness actuator
Warping harness leaf-spring
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 37
Tower & Locks Installed
Tower Assemblywith Repeatable Interface
Electrical Connector Bulkhead Panel
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 38
Fixed Frame Included
Fixed FrameNote: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 39
Installed on Mirror Cell
Adjustable Alignment Positioner (AAP)
Mirror Cell
Actuator
Actuator flexure
Note: Does not represent assembly sequence
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 40
Sector Boundary
Sector-F
Sector-A
PSA’s Clocked 60 degrees between sectors– Two fixed frame versions
– Sufficient clearance at boundary
Adjacent actuators35mm nominal clearance
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 41
Group of SegmentsView of Seven Adjacent Segments – Top View
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 42
Group of SegmentsView of Seven Adjacent Segments – Bottom View
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 43
AXIAL SUPPORT SYSTEM
SSA Design
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 44
Axial Support SystemTwo level, 27-point whiffletree system– All-Aluminum design (nearly)
Triangles and sheet flexures Aluminum
Rod Flexures Stainless Steel
Analysis shows high CTE of Aluminum to be acceptable
Lower machining costs and corrosion resistance a plus
– Triangles nested for compactness
Rod Flexures at pivot locations
Pivot Flexures at Moving Frame Connection
Mirror SupportRod Flexures
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 45
Axial Support SystemWhiffletrees Ride on Moving Frame– Moving Frame: 6061 Aluminum weldment
ActuatorRod Flexure
ClampHandling Feature
PivotFlexure
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 46
Axial Support SystemSheet Flexures:– Concept introduced by SALT
– Stabilize whiffletrees in XYSSA plane
Pivots (Kz) + Sheet Flexures (Kx, Ky, Rz) provide 4 Degrees of Stiffness
– Tip/Tilt (Rx & Ry) remain compliant
– Whiffletree mass is nominally balanced about sheet flexure plane
– Aluminum 7075-T651, 0.508mm (0.020”) thick
Sheet Flexures2 per WT
Pivots3 per WT
Sheet Flexure Attachment to Moving Frame, TypicalNo further discussion of Sheet Flexures
Questions?
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 47
Axial Support System27-Mirror support rod flexures– Invar pucks bonded to mirror using
3M EA-2216 EpoxyWell characterized adhesive
JPL heritage for Invar/Zerodur bonds (documented process )
0.250mm nominal bondline (0.010”)
– Stainless Steel rods connect pucks to triangles
304V Cold drawn 94% CW
250 ksi yield strength
– Threaded end connections:Stiff, strong, adjustable & removable
VentHole
VentHole
Mirror
Small WTTriangle
InvarPuck
Flexure:2.1mm OD x 143mm Long
Bondline
Detailed discussion: PDR Volume-5
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 48
Axial Support System9-Small whiffletree triangles – Extruded Aluminum: 6061 T6
– Low cost~$12 per extruded blank, in production qty.
3-Large load-spreader triangles– Cast Aluminum (A356 T51)
– Lowest manufacturing costComplex shapes & large size ideal for casting
No further discussion of Triangle design
Questions?
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 49
Axial Support SystemOptical Performance– Whiffletree support points and pivot locations determined by optimization
– Pivot locations unique for each of the 82 segment typesSee PDR Volume-2 for details
Axial support gravity print-thru:– Figured out at ςseg=0
– Springs-back as [1-cos(ςseg)]
– Surface error amplitude ~10 nm RMS (ςseg=90)
See PDR Volume-3 for details
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 50
LATERAL SUPPORT SYSTEM
SSA Design
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 51
Lateral Support SystemLateral Support Design– Simple Flat Central Diaphragm
Low costCompact (space limited by 45mm thick mirror)
– no decoupling flexures
– Diaphragm material: Invar 36 (one piece)Baseline for optical performance analysisPrefer to use INOVAR from Imphy Alloys (Fr.)
– High purity, w/Low Carbon content Low CTE [~1/2 of regular Invar (0.65 PPM/C)]Better temporal stability
– Bonded directly to mirror:Adhesive: 3M EA-2216, 0.250mm bondline (0.010”)
Diaphragm dimensions:– Rim OD: 150 mm OD, Hub OD 60 mm– Flexure region: OD 130mm, 0.350 mm thick
10 mm wide outer rim bonded to glass
– Mirror Pocket: 156 mm by 25.5 mm deep
Rimt=3mm
Central hubt=8.5mm
Flexuret=0.350mm
Detailed discussions:
PDR Volumes-3 & -5
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 52
Lateral Support System
Diaphragm: Cross-Section View
Mirror Segment
Moving Frame
Diaphragm
Adhesive Bond:Diaphragm to Glass
Adhesive layer
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 53
Lateral Support SystemMoving frame concept isolates diaphragm
Makes operating diaphragm deflections small:
High strength material not required
Lateral Support gravity print-thru– Lateral support gravity print-thru:
– Zero out at ςseg=0
– Springs-back as [sin(ςseg)]
– Surface error amplitude ~12 nm RMS (ςseg=90)
Diaphragm Attached to Moving Frame
Detailed discussion: PDR Volume-3
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 54
Tower, Guide Flexure, Locks and Registration
SSA Design
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 55
Tower & Guide FlexureTower & Guide Flexure:– Provide lateral load-path for SSA
Connect Moving Frame to Subcell (Fixed Frame)
– Accommodate segment piston/tip/tilt
– Guide flexure details in PDR Volume-5
Tower assembly includes:– ½ of the registration interface
– ½ of the SSA lock system
Tower: 6061-T6 Aluminum weldment
SSA Lock3 ea.
Guide Flexure
Registration3 ea. at 120 deg
Tower
Moving Frame (MF)
Guide FlexureAttached to MF at ID
Guide FlexureAttached to Tower at OD
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 56
Tower & Guide Flexure
Mirror Segment
MovingFrame
GuideFlexure
Clearance hole for Mirror Support Rod Flexure
Attached to MF
Attached to Tower
Convolution for piston compliance
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 57
SSA LocksLocks:– Three per SSA:
Secure Moving Frame to Tower
– Permanently installed
– Enable safe handling, installation & removal
– Support segment during actuator change-out
– Latched by spring-plunger detent
– Hardened cam keyed to handle
– Hardened insert mounted in moving frame
Cam
Spring Plunger
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 58
SSA Lock PositionsLocked:– Moving frame pushed to “Neutral” position
Nominal Clearance 0.250 mm
– MSA can be installed, removed and handled
– Actuator can be replaced
Unlocked:– Moving Frame and Tower not in contact
– Act as Piston/Tip/Tilt hard-stopNominal clearance +/-3 mm SSA range of travel
– outside range of actuator hard stops (+/-2.5mm)
Moving Frame
Moving Frame
No further discussion of Lock design
Questions?
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 59
RegistrationRequirements & Goals– Repeatability +/-0.050mm in-plane– Stiff connection in all DOF– Face-to-face axial registration with thru-bolt
Strong, stiff and easy to dimensionally inspectLateral registration features not in axial load path
– Sufficient strength to position segments at 14.5 deg inclination during installation
0.25g lateral load plus friction
– Cycles: Assume one Installation & Removal per year for 50 years (50 cycles)
Implies a near-kinematic designDesign concept:– Set of 3 tangential and axial contacts, 120 deg apart– Lateral registration features:
Tapered pin in V-groove with small in-plane radial clearance when assembled– Clearance allows Tower to move slightly in X,Y, & Clocking
– Axial registration features:Mating flat surfaces clamped by thru bolt
– Friction joint during operation
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 60
Registration Hardware
Tower Separated From Fixed Frame Tower Lowered to Fixed Frame
Captive Bolt Tightened to Clamp Joint
Registration mating sequence (typical 3 places @ 120 deg)
Conical Pin V-groove
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 61
RegistrationTapered pin:– Material: Ti 6Al-4V Annealed & Nitrided
120 ksi base metal
TiN: Rc70 surface coating for galling resistance
Insert ring:– Material: 17-4 PH Condition H1025
145 ksi yield strength
Contact stress– Contact force 1009N
210 kg at 14.5 deg inclination with sliding friction coefficient of 0.5
– 60 ksi max subsurface von Mises stressFSy = 2.0
Result:– Durable interface that will not Yield or Gall
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 62
RegistrationPin-Insert clearance:
Cost:– Machine shop quote: $400/set, in quantity
Registration Bushing Clearance(mm on Diameter)
Nominal Diameter mmDiameter Tolerance Min Max
Insert 20.050 0.015 20.035 20.065Tapered Pin 20.000 0.005 19.995 20.005
Clearance 0.030 0.070
No further discussion of Registration design
Questions?
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 63
WARPING HARNESS SYSTEM
SSA Design
PDR Volume-4 Dedicated to Design and
Analysis of Warping Harness
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 64
Warping Harness Approach & ArchitecturePurpose:– Allow automated periodic correction of low order surface distortions:
Residual errors from polishing
Coating stress distortion
Seasonal mean-value of thermal distortion
Segment positioning errors within the array (Focus and Astigmatism)
etc.
Fundamental Approach:– Extension of the Keck design
– Re-figure the mirror by bending it in a controlled manner using whiffletree
– Bending moments introduced into whiffletree by a set of moment actuators
– Actuators are motorized, instrumented and tied into the M1CS
Architecture:– 21 whiffletree joints are fitted with moment-actuators
– Lead screw pushes against an instrumented leaf-spring to create a moment
– Stepper motor drives lead screw to permit automation
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 65
Design Concept Actuator Schematic– Stepper motor driven screw displaces end of leaf-spring
– Strain gauge on leaf-spring provides feedback for motor control
– Motors will be mounted on the large whiffletree triangles and to the moving frame
Screw
Leaf-spring
Stepper Motor
Nut
Strain GaugeWT Joint Flexure
(sheet flexure not shown)
Axial Support Flexure
Large Triangle
Small Whiffletree TriangleSmall Whiffletree Triangle
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 66
Optical Performance Analysis
Mx’’ & My’’ Large Triangles, 3ea(Only M required)
Mx’ & My’ Outer Triangles, 6ea
MInner Triangles, 3ea(Mr not required)
Actuator Layout– 21 Actuators
Indicates Applied Moments(Equal and Opposite)
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 67
Optical Performance AnalysisActuator Layout– 21 Actuators integrated into axial support system
Leaf Spring (Typ.)
Actuator (Typ.)
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 68
SUBCELL
SSA Design
Fixed FrameAAPsActuator Flexure
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 69
Subcell DesignFixed Frame– Provides a stiff, stable interface between MSA and Mirror Cell
– Construction: Welded 6061-T6 Aluminum (2 versions due to segmentation)
– Interfaces:Mirror cell (via AAPs)
MSA (via tower registration features)
Actuators (bolted and pinned joints at ends of Fixed Frame)
Segment lifting jack (at center post) See PDR Volume 6 for details
– Deep cross-section required to meet 35 Hz for Lateral modeOptimized to reduce mass
Fixed Frame
ActuatorAttachment
AAP
NEXT SLIDE
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 70
AAP DesignAAP Requirements/Features– Range of Travel
+/-8mm adjustment in-plane– Mirror Cell mfg. tolerances (5mm) plus segmentation
effects (3mm)
+/-5mm vertical adjustment
– Aligned one time during construction and permanently locked/pinned
Jam nuts and match-drilled dowel pins
– Smooth adjustment (resolution)
– 30mm post diameter required for stiffness35 Hz lateral mode
– Welded Stainless Steel Post bolted to Mirror Cell
– Brass Spherical Nuts
– Stainless Steel Spherical Washers
– Special tools required to torque assy.Cross Section of AAP
Threaded Post: bolted to truss
Spherical Nut 2ea.
SphericalWasher 2ea.
Lock Nut 2ea.
Dowel PinsMatch drilled at
assy. 2 ea.
Fixed Frame integration discussed in PDR Volume-6
Alignment budget discussed in PDR Volume-2
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 71
Subcell DesignFixed Frame (Top plate removed)
Actuator AttachmentCastings
Jack Center Shaft Support and Bushings See PDR Volume-6 for Jack Design
Registration Pins3 ea.
Tower Clocking Pin See PDR Volume-6
AAP attach hole
Holes for surveying target holders 3ea.See PDR Volume-6
Jack Center Shaft Guide & Retention Pin See PDR Volume-6
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 72
Actuator FlexureDesign Overview– Actuator Rod Flexure Design – See PDR Volume-5 for Details
Flexible Region:7.23mm OD x 115mm Long
Knurled
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 73
Summary:Just Presented:– M1 Overview– SSA Project Overview– Key Requirements– Subsystem Designs
Additional Presentations to Follow:– Volume-2: System Level Calculations
– Volume-3: System-Level Finite Element Analysis
– Volume-4: Warping Harness Design and Analysis
– Volume-5: Flexure Design and Analysis
– Volume-6: Handling and Integration
– Volume-7: Summary and Future Plans
Additional Comments & Questions?
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 74
Acknowledgements
Acknowledgements:
The TMT Project gratefully acknowledges the support of the TMT partner institutions. They are the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology and the University of California. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Universities for Research in Astronomy (AURA) and the U.S. National Science Foundation.
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 75
BACKUP SLIDES
TMT.OPT.PRE.07.056.REL01 HPS-280001-0105 – Volume 1 – October 24-25 2007 – Slide 76
SSA MaterialsMaterial Properties for Key Components
Piece Part Drawing Number
Title QTY. MATERIAL Type/GradeModulus
GPaPoisson's
Ratio
Yield Strength,
MPa
Density kg/m3
CTE ppm/C
280-TMT-01-10001 Actuator Flexure 3 Titanium Ti 6Al-4V Annealed 112 0.31 862 4438 8.73280-TMT-01-11111 Mirror Support Rod Flexure 27 CRES 304V 94% Cold Work 179.3 0.28 1724 7933 15.57280-TMT-01-11112 Mirror Support Puck 27 Invar INVAR 130 0.29 260 8050 1.3280-TMT-01-11121 Central Diaphragm 1 Invar INVAR 130 0.29 260 8050 1.3280-TMT-01-11201 Triangle-Triangle Pivot 9 CRES 17-4 PH H1025 201.7 0.27 1000 7850 10.8280-TMT-01-11202 Moving Frame-Large Triangle Pivot 3 CRES 17-4 PH H1025 201.7 0.27 1000 7850 10.8280-TMT-01-11203 Sheet Flexure 6 Aluminum 7075 T651 71.7 0.33 462 2801 22.14280-TMT-01-11211 Inner Triangle A 3 Aluminum 6061 T6 Extrusiuon 69.65 0.33 228 2718 22.8280-TMT-01-11221 Outer Triangle B 3 Aluminum 6061 T6 Extrusiuon 69.65 0.33 228 2718 22.8280-TMT-01-11231 Outer Triangle C 3 Aluminum 6061 T6 Extrusiuon 69.65 0.33 228 2718 22.8280-TMT-01-11241 Middle Triangle D 3 Aluminum A356 T51 71.0 0.33 103 2691 20.7280-TMT-01-11242 Middle Triangle D Casting Per AMS 4217280-TMT-01-11243 Motor Mount 3 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11251 - P1 Warping Harness Leaf Spring - Inner 3 Aluminum 7075-T651 per QQ-A-250/12 72.1 0.33 462 2801 22.14280-TMT-01-11251 - P2 Warping Harness Leaf Spring - Outer 9 Aluminum 7075-T651 per QQ-A-250/12 72.1 0.33 462 2801 22.14280-TMT-01-11261 Moving Frame Machined Assembly 1 Aluminum 6061 T6 Extrusiuon 69.65 0.33 228 2718 22.8280-TMT-01-11262 Moving Frame Weldment 6061 T6 Extrusiuon 69.65 0.33 228 2718 22.8280-TMT-01-11263 Actuator Rod Clamp 3 CRES 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11264 Actuator Rod Clamp Mount 3 CRES 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11275 Lead Screw 21 CRES280-TMT-01-11281 Guide Flexure 1 Aluminum 7075-T651 per QQ-A-250/12 72.1 0.33 462 2801 22.14280-TMT-01-11282 Guide Flexure Clamp 1 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11283 Guide Flexure Mounting Flange 1 Aluminum 6061-T651 Per QQA-250/11 69.0 0.33 241 2718 22.77280-TMT-01-11284 Guide Flexure Center Clamp 1 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11301 Tower Machined Assembly 1 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11303 Tower Connector Mount 1 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-11304 V-Groove Insert, Registration 3 CRES 17-4 PH H1150 201.7 0.27 690 7850 10.8280-TMT-01-12001 AAP Post 3 CRES 304L 179.3 0.28 206 7933 15.57280-TMT-01-12002 AAP Jam Nut 6 Steel, Plated280-TMT-01-12003 AAP Upper Nut 3 Brass280-TMT-01-12004 AAP Lower Nut 3 Brass280-TMT-01-12005 AAP Lower Spherical Washer 3 CRES280-TMT-01-12006 AAP Upper Spherical Washer 3 CRES280-TMT-01-13001 Fixed Frame Machined Assembly 1 Aluminum 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-13002 Fixed Frame Weldment 6061-T651 Per QQA-250/11 69 0.33 241 2718 22.77280-TMT-01-13006 Tapered Pin, Registration 3 Titanium Ti 6Al-4V Annealed, TiN Coated