Simba GaoMECHANICAL / MECHATRONICS
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ASML-SPONSORED / UNIVERSITY OF MICHIGAN MDP

ASML DUV Stage Rolling Loop Test Rig

I helped build a rolling-loop test rig for ASML DUV stage research, reaching 100 m/s² acceleration with 9% mass accuracy.

My roleMechanical design and construction within the five-person team; contributed to integrated testing and data analysis.

  • Mechanism design
  • Dynamic testing
  • Instrumentation
  • Signal processing
Complete labeled test rig showing the displacement sensor, motion stage, and crank-slider.
Complete test rig · sensing, motion stage, and crank-slider
100 m/s²Peak acceleration target reached in test data
300 rpmNominal crank speed
9%Mass accuracy

01 / ENGINEERING PROBLEM

Measuring the load of a moving cable

ASML’s rolling loops deform as a precision stage moves, changing the load seen by its drive. We needed a scaled fixture that could reproduce rapid motion while recording force and displacement. The challenge was separating cable behavior from fixture vibration and sensor error.

02 / METHODS & ANALYSIS

Mechanism, sensing, and measurement

Project figures and hardware
Click images to enlarge

01

Generate the required motion

Close-up of the built rolling-loop fixture, moving carriage, and onboard electronics.
Crank-slider CAD and its manufactured motor-and-shaft assembly.

I worked on the crank-slider fixture because commercial stages meeting the acceleration target exceeded the budget. A 75 mm crank radius, 200 mm connecting rod, and 300 rpm operating point set the intended motion.

02

Integrate sensing on the moving carriage

Exploded carriage design with load-cell mounts, accelerometer holder, Arduino, and battery.
  1. ForceLoad cell between the carriages
  2. PositionStationary laser distance sensor
  3. AccelerationOnboard accelerometer; displacement-derived estimate used in final results

The team combined force, position, and acceleration measurements with onboard logging. When the accelerometer proved unreliable during high-g motion, the final analysis used derivatives of filtered displacement; this made mechanical stability and filtering especially important.

03 / RESULTS & OUTCOME

Motion and mass measurement results

PHYSICAL TEST RIG
Motion profiles reconstructed from measured displacement, with displacement, velocity, and acceleration requirements marked.
Motion reconstructed from measured displacement; acceleration was not independently confirmed by a reliable accelerometer trace.
>100 m/s²Reported peak acceleration
2.4 m/sReported peak speed
9%Mass accuracy

The rig reproduced the required stage motion and achieved 9% mass accuracy. Force and displacement measurements supported the characterization of rolling-loop behavior across three cable configurations.