This paper demonstrates a method to visually measure the force distribution applied to a linearly elastic object using the contour data in an image. The force measurement is accomplished by making use of the result from linear elasticity that the displacement field of the contour of a linearly elastic object is sufficient to completely recover the force distribution applied to the object. This result leads naturally to a deformable template matching approach where the template is deformed according to the governing equations of linear elasticity. An energy minimization method is used to match the template to the contour data in the image. This technique of visually measuring forces we refer to as vision-based force measurement (VBFM). VBFM has the potential to increase the robustness and reliability of micromanipulation and biomanipulation tasks where force sensing is essential for success. The effectiveness of VBFM is demonstrated for both a microcantilever beam and a microgripper. A sensor resolution of less than +/- 3 nN for the microcantilever and +/- 3 mN for the microgripper was achieved using VBFM. Performance optimizations for the energy minimization problem are also discussed that make this algorithm feasible for real-time applications.
|Original language||English (US)|
|Number of pages||9|
|Journal||IEEE Transactions on Pattern Analysis and Machine Intelligence|
|State||Published - Mar 2004|
Bibliographical noteFunding Information:
This research was supported in part by the US National Science Foundation through grant numbers IIS-9996061 and IIS-0208564. Michael Greminger is supported by the Computational Science Graduate Fellowship (CSGF) from the US Department of Energy.
- Deformable templates
- Force measurement
- Nonrigid tracking