Student: Matthew Bellassai Advisor: Edward Morse, Tori Welty SREU 2013 Center for Precision Metrology, Mechanical Engineering, University of North Carolina at Charlotte

1. Background 2. Project Goal 3. Methods 4. Experimental Setup 5. Results 6. Conclusion 7. References

(Richter, 2009)

A Laser Tracker is a laser-based spherical coordinate measurement system. (ASME B89)

The current ASME standards incorporate the use of static measurements with laser trackers.

The ability to take accurate repeatable measurements dynamically would both save time and money in industry.

Incorporate the scanning function of Laser Trackers in the current ASME code for dynamic measurements

To what accuracy is each coordinate when measurements are taken in motion What speed will significant error be introduced

Elevation

Azimuth Distance

*Laser Tracker Axes

*Laser Tracker Internal Operation

*(Bridges, 2009)

Identify sources of error and isolate them

Build a system to take measurements that provides a geometrically consistent shape that is repeatable and accurate

Allow Laser Tracker to have symmetrical movements in all axis with respect to a rotational axis that is coincident to the axis of rotation

Using an Air Bearing Spindle, errors will be in the nanometer range around its various axes Produce a measurable and controllable angular rotation or position using a closed loop feed back system Provide the possibility of using the spindle position to trigger the trackers to record a measurement

Mechanical and Electromechanical System Provides Control of Speed and Position

PID Control Loop Block Diagram¹

DC Brushed Motor² Quadrature Encoder³ DAQ4 1. (National Instruments, 2011) 2. (Shutterdrone, 2010) 3. (Bogan, 2000) 4. (National Instruments)

Motor Quadrature Encoder

Gears and Belt

The system can measure speed up to 119,000 RPM with a resolution of 1/10080 of a revolution (0.0357°) With the 0.6096 meter (2 ft.) ball bar we can see register a change in arc length of 190 µm from the drive mechanism (used for triggering and comparison)

Kinematic Mount Air Bearing Spindle

Kinematic Coupling – Deterministic coupling that makes contact at a number of points equal to the number of degrees of freedom that are to be restrained. Being deterministic makes performance predictable and also helps to reduce design and manufacture cost. (Richter, 2009)

Fast Scan • Range 50 micron to

-60 micron

Slow Scan • Range 50 micron to

-50 micron

Leica Scan • Range 50 micron to

-50 micron

API Scan • Range 120 micron to

-150 micron

A large volume of data collection may be performed from which a correlation between speed and error can be determined Our method for testing the Laser Trackers in a dynamic coordinate collection setting can be recorded and used in the proposal to amend the current standards to include dynamic measurements with Laser Trackers

Hexagon Metrology Faro Leica API New River Kinematics National Instruments Microsoft Professional Instruments Company Brunson Instrument Company

Spatial Analyzer Labview Excel PTC Creo National Institute of Standards and Technology

Bogan, L. (2000, Nov). Digital Setting Circles for Amateur Telescopes. Retrieved July 13, 2013, from Bogan.ca: http://www.bogan.ca/astro/telescopes/digtcrcl.html

Bridges, B. (2009, June 25). How Laser Trackers Work. Retrieved July 02, 2013, from Quality Digest: http://www.qualitydigest.com/inside/twitter-ed/how-laser-trackers-work.html

National Instruments. (2011, Aug 26). Teach Tough Concepts: Closed-Loop Control with LabVIEW and a DC Motor. Retrieved July 12, 2013, from NI.com: http://www.ni.com/white-paper/12944/en/

National Instruments. (n.d.). NI USB-6218. Retrieved July 13, 2013, from National Instruments: http://sine.ni.com/nips/cds/view/p/lang/en/nid/203484

Richter, A. (2009, October). Cutting Tool Engineering Plus. Retrieved July 13, 2013, from CTE Mag: http://www.ctemag.com/aa_pages/2009/0910_MilitaryParts.html

Shutterdrone. (2010, May 27). Choosing a Motor Type for Your Motion Control Rig. Retrieved July 13, 2013, from OpenMoCo: http://openmoco.org/node/179

Slocum, A. H. (1992). Precision Machine Design. Englewood Cliffs: Prentice-Hall, Inc.

Suter, S. L. (1995). Analysis of a Spindle's Error Motions. Charlotte: Heckman Bindery Inc. .

ASME B89.4.19-2006, “Performance of Laser-Based Spherical Coordinate Measurement Systems,” ASME, New York, NY, 2006.

Edward Morse Tori Welty Jimmie Miller John Brian Franklyn Green

Stuart Smith Peter Tkacik Roland Hege Jim Haig