Vision-Based Force Measurement Using the Boundary Element Method

Michael Greminger, University of Minnesota

Many tasks performed by robotic systems require interactions with deformable objects. Examples include cell manipulation and robotic surgery. These deformable objects are often easily damaged so it is desirable to be able to measure the force field applied to the object. This poster presents a method to measure the force field applied to a linearly elastic object through the use of computer vision. The objects are modeled using the boundary element method (BEM). BEM, like the finite element method (FEM), is a technique that can be used to model an elastic solid. BEM differs from FEM in that only the contour of an object needs to be meshed for BEM, making this method attractive for computer vision problems. In order to measure the force field from an image, a deformable template is defined that uses BEM to model displacements. The template is registered to the image by applying a force field that deforms the template to match the image. This force field is found using an energy minimization approach. Results are presented for linearly elastic objects and it is demonstrated how this work can be extended to objects with non-linear material behavior.

Abstract Author(s): Michael Greminger<br />Bradley J. Nelson