Dr. Peter M. Thompson Profile

Dr. Peter M. Thompson

Chief Scientist at GMTO Corp

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Author

Publications (20)

Proceedings Article | 30 August 2022 Poster + Paper

GMT ASM prototype dynamic and optical tests results

M. Andrighettoni, R. Biasi, M. Manetti, M. Tintori, D. Gallieni, P. Thompson, J. Spanos, A. Bouchet, F. Groark

Proceedings Volume 12185, 121857X (2022) https://doi.org/10.1117/12.2630750

KEYWORDS: Optical testing, Prototyping, Fluid dynamics, Sensors, Interferometers, Temperature metrology, Electronics, Cooling systems, Sensor calibration

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Proceedings Article | 30 August 2022 Poster + Paper

GMT ASM co-phasing numerical simulation and experimental results

M. Manetti, R. Biasi, M. Tintori, D. Gallieni, P. Thompson, J. Spanos, A. Bouchez, F. Quiros, B. Sitarski, F. Groark

Proceedings Volume 12185, 121857V (2022) https://doi.org/10.1117/12.2630749

KEYWORDS: Sensors, Mirrors, Telescopes, Device simulation, Error analysis, Computer simulations, Numerical simulations, Motion models, Control systems, Deformable mirrors

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Proceedings Article | 29 August 2022 Presentation + Paper

The GMT telescope metrology system design

Breann Sitarski, Andrew Rakich, Hugo Chiquito, Wylie Rosenthal, Antonin Bouchez, William Schoenell, Bo Xin, Priscila Pires, Joel Nissen, P. Schurter, Richard Demers, Peter Thompson, Brian McLeod, Bijan Nemati, Glenn Brossus, Brian Walls, Heejoo Choi, Guillermo Gonzalez, David Nemati

Proceedings Volume 12182, 1218207 (2022) https://doi.org/10.1117/12.2630598

KEYWORDS: Mirrors, Retroreflectors, Sensors, Telescopes, Error analysis, Collimators, Prototyping, Metrology, Laser metrology

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Proceedings Article | 13 December 2020 Poster + Paper

GMT adaptive secondary mirrors subsystem final design

Daniele Gallieni, Matteo Tintori, Pierluigi Fumi, Lorenzo Crimella, Roberto Biasi, Gerald Angerer, Mauro Manetti, Antonin Bouchez, Glenn Brossus, Frank Groark, Peter Thompson

Proceedings Volume 11448, 114485K (2020) https://doi.org/10.1117/12.2562698

KEYWORDS: Mirrors, Telescopes, Deformable mirrors, Optical instrument design, Actuators, Reliability, Safety, Sensors, Electronics, Control systems

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Proceedings Article | 13 December 2020 Presentation + Paper

The GMT Telescope metrology system: easing the complexity of initial and operational alignment and increasing observing efficiency

Breann Sitarski, Andrew Rakich, Hugo Chiquito, Wylie Rosenthal, Priscila Pires, Peter Thompson, Francisco Aguayo, William Schoenell, Patricio Schurter, Glenn Brossus, Rodolphe Conan, Antonin Bouchez, George Angeli, Keath Beifus, King-Ming Lam, Paul Gardner, David Thomas

Proceedings Volume 11445, 114450T (2020) https://doi.org/10.1117/12.2560681

KEYWORDS: Optical alignment, Telescopes, Metrology, Observatories, Mirrors, Optical components, Visible radiation, Infrared telescopes, Lanthanum, Optical instrument design

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Proceedings Article | 10 July 2018 Presentation

Multivariable frequency response analysis methods for GMT motion control systems (Conference Presentation)

Peter Thompson, David Schwartz, George Angeli

Proceedings Volume 10705, 1070511 (2018) https://doi.org/10.1117/12.2314019

KEYWORDS: Control systems, Motion analysis, Mirrors, Telescopes, Ferroelectric materials, Large telescopes, Sensors, Structural dynamics, Actuators

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Extremely large telescopes are characterized by high degree of freedom control systems used to coordinate multiple segments and mirrors. The dynamics can interact so that single loop requirements do not provide sufficient stability and performance robustness. This paper reviews the relevant multivariable robustness and performance methods, and presents examples from Giant Magellan Telescope (GMT) motion control systems. Singular value bounds of multivariable frequency responses are well developed computational tools that provide a methodology that can be used for telescope analysis. The singular value bounds are relevant because they give the maximum sensitivity for coupled, multivariable systems. Singular values are recommended for analysis, and can be considered for requirements. With sufficient numbers of sensors, these multivariable bounds are measurable and hence can be validated. There is a practical reason for using multivariable tools, to combine many, perhaps thousands of transfer functions and/or measurements that can be compared against singular value bounds. The first example is the AZ/EL mount control. Coupling tends to be small, hence single-input analysis tools suffice, nevertheless the mount control system provides a good introduction to multivariable methodology. The maximum singular value of both the sensitivity and complementary sensitivity functions provide a good bound for crossover robustness near the position control bandwidth, typically +6 dB near 1 Hz. The high frequency region of the complementary sensitivity function provides a good bound on robustness with respect to unmodeled structural dynamics, typically–40dB above the maximum frequency of the finite element modes. Similar multivariable stability robustness bounds can be applied to position control of the M2 assembly, for both the macrocell relative to the top end assembly, and each mirror subassembly relative to the macrocell. The latter includes control of the Fast Steering Mirror, where 21 PZT actuators control the tip and tilt of seven secondary mirrors. The risk is the 21 PZT control loops meet good classical phase and gain margin robustness metrics when measured as individual, single-input-single-output systems, but the multivariable bound exceeds either the +6 dB or – 40 dB bound. This can occur due to interaction in the macrocell, the structure used to support the individual segments. Whether or not this interaction occurs depends on the bandwidth of the control system relative to the structural modes of the macrocell. This tradeoff is important, and the maximum singular value is a good tool to test for this sensitivity.

Proceedings Article | 6 July 2018 Paper

Implementation of W. M. Keck Observatory's telescope control system upgrade

Tomas Krasuski, Peter Thompson, Ben McCarney, Shui Kwok, Ean James, Kevin Tsubota, Mike Pollard, Kevin McCann

Proceedings Volume 10700, 107005I (2018) https://doi.org/10.1117/12.2314165

KEYWORDS: Computer programming, Telescopes, Control systems, Information operations, Field programmable gate arrays, Mirrors, Safety, Switches, Photonic integrated circuits, Keck Observatory

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Launched in 2009, Keck Observatory’s Telescope Control System Upgrade (TCSU) project set out to improve Keck’s telescope pointing, tracking, and offsetting performance as well as increase maintainability and reliability. The project went online full time on the Keck 2 telescope in October 2017 and on the Keck 1 telescope in March 2018 after a notable delay due to a re-design of the azimuth and elevation encoder mounting systems. This paper discusses the details and challenges of implementing this large and complicated system while never requiring a shutdown of either telescope. The TCSU project replaced all of the major elements of the telescope controls, rotator and secondary mirror controls, and safety system. National Instrument’s reconfigurable I/O technology (i.e. NI RIO), with their embedded field programmable gate arrays (FPGAs), are used as the core of the telescope’s digital velocity control loop, structural filter, and tachometer filter. They were also used to create a monitoring and safety system for the rotator velocity controller as well as reading the newly installed tilt meters used to greatly improve pointing performance. Delta Tau’s family of “Brick” programmable multi-axis controllers, i.e. PMAC or BRICK, are used to control the rotator and secondary mirror. They enable better tuning and faster slew speeds for these subsystems. An Allen Bradley’s ControlLogix® controller and the family of FLEX™ Input/Output (IO) modules were used to create a distributed safety system able to handle a wide variety of signal types. This technology refresh based on commercial off the shelf equipment replaced much of our obsolete and custom equipment. A significant part of the project was the installation of new telescope azimuth and elevation position encoders based on Heidenhain’s 40 micron grading tape scales. Interpolated to a 10 nanometer resolution, the new encoders provide true 4 mas resolution in azimuth and 1 mas resolution in elevation. This is a big improvement to Keck’s position sensing when compared to the old rotary incremental encoders. The installation required a significant amount of mechanical infrastructure to house them. Additionally, two tilt meters were installed to sense the telescope’s varying vertical angle as a function of azimuth, mainly due to the azimuth bearing’s axial runout. The encoders and tilt meters are the primary reason for achieving the greatly improved pointing and tracking performance [1]. Finally, a switching solution using solid state relays and dual network switches was installed to provide seamless and rapid switching between the old and new control systems during commissioning. Although this component is a simple design and does not boast of any new technology, it is one of the key components that enabled the successful testing of the new equipment while keeping the old system operational as a backup for night time observing as well as for baseline performance comparisons. It allowed us to switch a variety of signal types and was very cost effective when compared to available products.

Proceedings Article | 22 July 2014 Paper

CCAT mount control using de-convolution for fast scans

Peter Thompson, Stephen Padin

Proceedings Volume 9145, 91451P (2014) https://doi.org/10.1117/12.2057250

KEYWORDS: Electroluminescence, Computer programming, Sensors, Control systems design, Finite element methods, Control systems, Telescopes, Turbulence, Phase modulation, Radium

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Proceedings Article | 22 July 2014 Paper

Keck telescope mount control redesign to improve short move performance

Peter Thompson, Tomas Krasuski, Kevin Tsubota, Jimmy Johnson

Proceedings Volume 9145, 914557 (2014) https://doi.org/10.1117/12.2057225

KEYWORDS: Electroluminescence, Control systems, Telescopes, Computer programming, Radium, Phase modulation, Linear filtering, Amplifiers, Field programmable gate arrays, Analog electronics

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Proceedings Article | 10 November 2011 Paper

Control system modeling for the Thirty Meter Telescope primary mirror

Douglas MacMynowski, Peter Thompson, J. Shelton, Lewis Roberts, M. Colavita, Mark Sirota

Proceedings Volume 8336, 83360R (2011) https://doi.org/10.1117/12.914941

KEYWORDS: Sensors, Actuators, Telescopes, Mirrors, Performance modeling, Finite element methods, Servomechanisms, Motion models, Control systems, Thirty Meter Telescope

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Proceedings Article | 6 August 2010 Paper

Robustness of Thirty Meter Telescope primary mirror control

Douglas MacMynowski, Peter Thompson, Chris Shelton, Lewis Roberts

Proceedings Volume 7733, 77332J (2010) https://doi.org/10.1117/12.857380

KEYWORDS: Sensors, Actuators, Mirrors, Error analysis, Servomechanisms, Telescopes, Control systems, Structural dynamics, Tolerancing, Thirty Meter Telescope

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Proceedings Article | 5 August 2010 Paper

Dynamic characterization of a prototype of the Thirty Meter Telescope primary segment assembly

Martin Regehr, Peter Thompson, M. Mark Colavita, James Moore, Mark Sirota, Eric Williams

Proceedings Volume 7733, 77332G (2010) https://doi.org/10.1117/12.858155

KEYWORDS: Actuators, Mirrors, Data modeling, Optical benches, Servomechanisms, Finite element methods, Calibration, Prototyping, Motion models, Thirty Meter Telescope

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Proceedings Article | 5 August 2010 Paper

Servo design and analysis for the Thirty Meter Telescope primary mirror actuators

Peter Thompson, Douglas MacMynowski, Martin Regehr, M. Mark Colavita, Mark Sirota

Proceedings Volume 7733, 77332F (2010) https://doi.org/10.1117/12.857371

KEYWORDS: Actuators, Mirrors, Ferroelectric materials, Servomechanisms, Telescopes, Control systems, Sensors, Image segmentation, Resistors, Thirty Meter Telescope

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Proceedings Article | 10 July 2008 Paper

Analysis of the TMT mount control system

Peter Thompson, Douglas MacMynowski, Mark Sirota

Proceedings Volume 7012, 70121P (2008) https://doi.org/10.1117/12.790277

KEYWORDS: Telescopes, Computer programming, Sensors, Control systems, Performance modeling, Phase modulation, Finite element methods, Electroluminescence, Astatine, Wavefront sensors

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Proceedings Article | 10 July 2008 Paper

TMT telescope structure system: design and development progress report

Kei Szeto, Scott Roberts, Mike Gedig, Glenn Austin, Christie Lagally, Steven Patrick, Dominic Tsang, Doug MacMynowski, Mark Sirota, Larry Stepp, Peter Thompson

Proceedings Volume 7012, 70122G (2008) https://doi.org/10.1117/12.787002

KEYWORDS: Telescopes, Optical instrument design, Control systems, Structural design, Safety, Control systems design, Finite element methods, Space telescopes, Earthquakes, Thirty Meter Telescope

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Proceedings Article | 10 July 2008 Paper

Control analysis of the TMT primary segment assembly

Peter Thompson, Douglas MacMynowski, Mark Sirota

Proceedings Volume 7012, 70121N (2008) https://doi.org/10.1117/12.790287

KEYWORDS: Mirrors, Actuators, Control systems, Finite element methods, Sensors, Telescopes, Control systems design, Phase modulation, Mirror structures, Thirty Meter Telescope

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Proceedings Article | 9 July 2008 Paper

Analysis of TMT primary mirror control-structure interaction

Douglas MacMynowski, Peter Thompson, Mark Sirota

Proceedings Volume 7017, 701715 (2008) https://doi.org/10.1117/12.787003

KEYWORDS: Actuators, Servomechanisms, Mirrors, Telescopes, Control systems, Sensors, Structural dynamics, Feedback control, Optical instrument design, Thirty Meter Telescope

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Proceedings Article | 27 July 1998 Paper

Integrated design of smart rotor and robust control system

Vineet Sahasrabudhe, Peter Chen, Peter Thompson, Bimal Aponso

Proceedings Volume 3329, (1998) https://doi.org/10.1117/12.316905

KEYWORDS: Control systems design, Actuators, Data modeling, Control systems, Aerodynamics, Motion models, Optimization (mathematics), Failure analysis, Vibration control, Denoising

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Proceedings Article | 21 March 1997 Paper

Autoguider servo design and testing of the W. M. Keck Telescope

Mark Sirota, Kevin Ho, John Gathright, Hilton Lewis, William Lupton, Peter Thompson

Proceedings Volume 2871, (1997) https://doi.org/10.1117/12.268983

KEYWORDS: Servomechanisms, Telescopes, Computer programming, Cameras, Systems modeling, Optical instrument design, Mirrors, Performance modeling, Space telescopes, Error analysis

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Proceedings Article | 1 June 1994 Paper

Azimuth and elevation servo performance of the W.M. Keck Telescope

Mark Sirota, Peter Thompson, Henry Jex

Proceedings Volume 2199, (1994) https://doi.org/10.1117/12.176183

KEYWORDS: Telescopes, Servomechanisms, Control systems, Computer programming, Electroluminescence, Error analysis, Mirrors, CCD cameras, Optical instrument design, Performance modeling

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