34th Annual Meeting

 

Monday – Friday
October 28 – November 1, 2019
Wyndham Grand Downtown Pittsburgh
Pittsburgh, Pennsylvania, USA

Conference Chair
Stephen J. Ludwick, Aerotech, Inc.


Photo Credit: David Reid/VisitPittsburgh

Tutorials

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Tutorials will be held on Monday-Tuesday, October 28-29, 2019 this year (instead of the usual Sunday-Monday)
Stay tuned for tutorials for this meeting


Tutorials that will be offered at this year’s conference:

“Introduction to Robust Controls”
Dr. Mark Bedillion (Carnegie-Mellon)
This tutorial introduces the tools and techniques used to design feedback controllers that achieve deterministic performance on uncertain systems. It begins by discussing sources of uncertainty in the dynamic response of mechatronic systems, explaining the difference between structured and unstructured uncertainties, and developing tools for mathematically describing uncertainty in a way that is amenable to feedback control design. The tutorial will then introduce robust control techniques (e.g. control) and demonstrate how they are related to, but distinct from, classical frequency domain loop shaping techniques. Using dynamic models augmented with uncertainty descriptions, we will design feedback algorithms using tools that achieve stability and performance over the entire range of possible responses. Finally, we will demonstrate how the resulting high order controllers can be reduced for practical implementations.

This is a somewhat advanced class in feedback control systems, and it is expected that the attendees will have a basic understanding of linear algebra and frequency domain tuning techniques. Students without such a background are recommended to take “Introduction to Controls” prior to joining this tutorial.

“Design Principles for Precision Mechansims I” & “Design Principles for Precision Mechansims II”
Prof. Dannis M. Brouwer, University of Twente
Piet C.J. van Rens, Settels Savenije van Amelsvoort
The Design Principles for Precision Mechanisms tutorial is about the conceptual approach to designing precision mechanisms like manipulators, scientific instruments, precision equipment, etc. It focuses on the mechanical aspects of precision in a mechatronic system context. Extra attention is devoted to essential “details” making the difference between a good and bad design. Both practical and theoretical approaches will be detailed. The analysis of the tutorial subjects will be both intuitively and model-based. Subjects of the tutorial:
• Design for Stiffness: The energy approach and Optimal material usage.
• Exact Constraint Design: Analysis methods, practical and mathematical (FACT, Grübler and loop-closure counting) and Static indeterminacy: pro’s and con’s.
• Flexure Design for Precision: Basic flexure elements; Stages based on flexure elements; Design for stiffness with flexures with a large range of motion; 2D non-linear flexure analysis.
• Minimizing hysteresis in precision systems: In couplings and sliding motion mechanisms and In clamped flexures.
• Reference systems: Dealing with accuracies in manufacturing and assembly.

“Exact-constraint Design of Precision Flexures: Part 1 and 2”
Dr. Jonathan Hopkins (UCLA)
Advanced flexure synthesis principles, modeling approaches, engineering tools, and best practices. Applications: precision motion stages, general purpose flexure bearings, and MEMs/Nano-scale positioning systems. Emphasis on kinematic flexure synthesis using principles of constraint-based design, screw theory, and projective geometry. Lectures, examples, and hands-on exercises involving “build-your-own” flexure kits. Students encouraged to bring flexure examples for analysis and discussion.

Part 1 Overview: (4hrs)
• Flexible Constraint Theory: Constraint and DOF relationship; exact, over, and underconstraint; modeling flexures using constraint lines; kinematic equivalence
• Constraints and the Motions they Permit: Modeling translations as rotations; principles of projective geometry in flexure synthesis; rule of complementary patterns; introduction to freedom and constraint spaces as deterministic synthesis tools
• Freedom and Constraint Topologies (FACT): Designing parallel flexure systems using freedom and constraint spaces.

Part 2 Overview: (4hrs)
• Synthesizing Serial Flexure Systems using FACT: Intermediate freedom spaces; stacking parallel modules; synthesizing parallel and serial elements.
• Actuating Flexure Systems: Calculating static and dynamic actuation spaces as a way to select the optimal kind, number, location, and orientation of actuators for actuating systems with minimal parasitic error.
• Case Study Analysis and Discussion: Practice applying FACT to the design of precision flexure systems. Analyze and discuss flexures brought to the course.
No previous experience is required for either part but Part 1 should be taken as a prerequisite to Part 2.

“Dynamic error budgeting for mechatronic machines”
Dr. Leon Jabben (MI-Partners)
In this course you will learn that dynamic error budgeting (DEB) is not so much about error budgeting but much more about a framework that can be used in designing mechatronic (precision) machines. It is a framework that is based on the modeling of (stochastic) disturbances by means of their Power Spectral Densities and how these propagate through a mechatronic system (with feedback). The impact of the various disturbances are then best compared in a so-called Cumulative Power Spectral plot, which show the cumulative power for each disturbance towards the performance channel of interest over frequency.

Besides predicting the performance, the DEB framework allows in this manner to compare the impact of “incompatible” disturbances with units such as voltage, newton, meter/s etc. Thereby enabling to answer system design questions, for example on whether to focus on a better amplifier, a better floor isolation system, or instead limiting the impact from a specific mechanical resonance.

This course discusses the theory and modeling of disturbances typically found in mechatronic systems, a case study, as well as some notes of attention in applying the framework. Given the limited time, the material shall not be covered fully in-depth, but will focus more on the practical application. A basic understanding of feedback systems and control design is prerequisite.”

“Parametric assessment for specifying, calibrating and verifying precision instruments or machine tools”
Dr. Jimmie Miller (University of North Carolina – Charlotte)
Procurement and subsequent testing of machine tools requires the buyer and seller to speak the same language. This tutorial reviews international standardized parametrization and tests which are used to specify these machines for procurement or usage including determining when a rebuild or correction may be warranted. Topics include determinism, carriage errors, instrumentation for measuring carriage errors, analysis of acquired data to determine the desired measurand parameters. Other tests such as carriage alignment errors, dynamic errors etc will also be addressed. This tutorial will also be of interest to anyone who uses or builds instruments which have positioning stages

“Parametric mathematical modeling of instruments or machine tools for volumetric performance prediction or process correction”
Dr. Jimmie Miller (University of North Carolina – Charlotte)
Parametric mathematical models are useful for design error budgeting, manufactured part tolerance prediction with uncertainties, and process correction in various stages of a machines life cycle. Errors in the constrained six-degrees of freedom of carriages generate dimensional errors in a workpiece. This tutorial addresses how to set coordinate frames and measure the errors of the linear or rotary stages of a machine in order to volumetrically assess and correct for those errors. Both vector models with rotation transformation and homogeneous transformation models are addressed for the participant. Uncertainty determination is addressed pending time constraints. This tutorial will also be of interest to anyone who uses or builds instruments which utilize positioning stages.

“Large Scale Metrology”
Dr. Ed Morse (UNCC)
Description: From the perspective of a precision engineering, large-scale metrology might span dimensions ranging from about one meter to dimensions exceeding one hundred meters. This tutorial discusses the attributes of both workpieces and instruments that make large-scale metrology different from “traditional” dimensional metrology. The operational principles of the various instruments will be discussed, as well as strategies for utilizing multiple instruments for different aspects of the same measurement. The national and international standards that are used to specify the performance of these instruments will also be covered. The influence of the workpiece on measurement uncertainty is much greater for very large workpieces than for conventional parts – identifying and mitigating these influences is central to effective large scale metrology, and will be discussed in detail.

“The New SI”
Dr. Jon Pratt, Leon Chao, and Stephan Schalmminger (NIST)
As a precision engineer you’ve probably heard about the “SI redefinition” which goes into effect worldwide on May 20, 2019. It has been described as a “fundamental pivot point in humanity.” But what does it actually mean for us and how we measure?

NIST’s own Jon Pratt, Stephan Schlamminger, and Leon Chao will break it all down for us – covering topics ranging from the historical and political underpinnings of the International System of Units, to the very concept of a unit of measure, to the very nature of physical constants and their roles in physics and now measurement. The team will give a glimpse into the future of quantum standards, and they will offer tips on how you too can now realize mass by exploiting well-known concepts of precision engineering.

“Fundamentals of Precision Design”
Dr. Alex Slocum (MIT)
This tutorial provides a fast-paced hands-on introduction to rapid precision machine design based on FUNdaMENTAL principles including theory and best practices. Topics include: initial error allocation to enable rapid design, principles of accuracy, repeatability and resolution, bearings, structures, and actuators. Kinematic and elastic averaging-based designs and the implications for bearing life and dynamic performance are stressed with F=kx and  = sqrt(k/m) as recurring themes throughout the design of a machine. Examples will be presented to show how FUNdaMENTAL principles are critically important for an engineer to understand in order to be able to most effectively use modern design tools such as solid modeling and finite element analysis in the design of precision machines. Attendees are encouraged to bring pencils and paper to learn from solving real problems as part of the lecture.

“Error Modeling and Error Budgeting”
Dr. Alex Slocum (MIT)
This tutorial is the continuation of the tutorial “Fundamentals of Precision Design“ as it assumes working knowledge of FUNdaMENTAL principles. Starting with the idea of error apportionment as a means to guide development of the overall machine and its component axes, first order analysis is used to fill out a design to meet the required accuracy goals. The initial focus is on geometric, load induced, and thermal errors of the machine in the initial design phase. As the design progresses, an overall error budget is created using a spreadsheet-based model provided. This method helps the designer with selecting machine configurations and components, and tradeoffs to meet the desired performance specification for the machine.

 

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