U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia  Automatic image interpretation and creation of solid model from optimized topology image.  Image capturing of fabricated devices.  Image processing for edge-extraction and object- finding.  Writing image data as an IGES file for Pro-Engineer.  Vision-based metrology for meso-scale ceramic devices.  Vision-based recovery of forces presented in the deformable structure. Vision-based Extraction of Geometry and Force from Fabricated Micro Device

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Performance Specifications Synthesis Solution Refined Design Solution Meshed Model for Analysis Solid Model from the Optimized Device Digital Format for SFF or CNC Mask Layout for Microfab. Micro Prototype Macro Prototype Refined Prototype CAD model from the macro prototype Fabrication/Prototyping Digital Interface Design Reverse Engineering Solid model from microscopic images

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia From optimized compliant topology image to a solid model IGES model with line and arc segments Optimized compliant topology using material density design parameterization Image processing, edge extraction, and object finding ABS plastic macro prototype manufacturing

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia From fabricated MEMS device to a solid model Optical microscope image of a compliant micro crimper After edge extraction 5 µm

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia From fabricated MEMS device to a solid model IGES model exported into Pro-E with line and arc segments Extruded solid model ready for behavioral simulation

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Macro prototype of a micro wedge motor (Allen, 1998) The micro prototype was made using Sandia’s SUMMiT process.

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Lithography masks for a micro wedge motor

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Premise: Assuming material behavior and properties, forces can be estimated from underformed and deformed geometry of a flexible structure. Vision-based force sensing Goal: Non-contacting, non-interfering force sensor based on vision and computation.

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Image capturing before and after deformation Displacements Strains Stresses Forces Material properties

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia y z At time t = 0 (Undeformed) At time t (Deformed) o x Computing the deformation gradient Deformation gradient

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Computing the large strain Logarithmic strain

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Computing the stress and element forces Material properties for plane-stress condition Stress Element forces

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Force recovery Large strain caseSmall strain case

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia  The procedure for computing strains from displacements is prone to numerical error.  The computed strain is very sensitive to even small perturbations in displacement data.  The sensitivity is worse for small strains than large strains. Sensitivity analysis Let the left Cauchy-Green matrix be written in the following form: Define the sensitivity of the relative error for strain as follows: Sensitivity analysis shows and will approach infinity when the strain is very small.

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Macro-scale experiment Deformed macro-beamVision based load recovery

U. of Pennsylvania, Mar University of Pennsylvania, Philadelphia Micro-scale experiment Output F |D-D0| < threshold Initialization Solve displacement D Calculate stiffness Kt  F=inv(Kt)(D0 – D) F=F+  F Flow-chart for single force recovery Deformed micro-beam Probe Beam