The measurement of low-magnitude shear forces is essential for material characterization and in-hand object pose estimation for robotic applications. Previous work had demonstrated the ability to directly measure force using an optical GaN nanopillar sensor when combined with Multiphysics simulations. To investigate the accuracy of Multiphysics simulations, we use a commercially available six-axis force/torque sensor as our stress applicator with a polymer stamp mounted on the force sensing element. By investigating the accuracy of the Multiphysics simulations, we generated a mapping between applied shear force and our nanopillar tactile sensor response. We can use this mapping for robotic gripping applications.
A novel force sensor capable of determining both the direction and magnitude of the force is proposed and demonstrated. The sensor structure is based on two orthogonally oriented arrays of GaN (Gallium Nitride) elliptical nanopillars and a digital CMOS (Complementary Metal Oxide Semiconductor) image sensor. The pixelated array also enables twodimensional force mapping. The directional sensitivity originates from the breaking of the nanopillar symmetry and the orthogonal orientation of the arrays. Each array is more sensitive to stress along the long axis of the nanopillars as opposed to the short axis of the nanopillars. Shear stress on the nanopillars causes a decrease in the overlap of the electron and hole wavefunctions which is proportional to the intensity of the light emitted from the nanopillars. Only a common bias, either optical or electrical, is needed across the entire device, making two-dimensional mapping simple and easily completed using a common digital CMOS camera. No stringent uniformity requirement across the sensor array is necessary. The data from an unstressed array is compared to the data from the same array under stress so that the relative change of emission intensity can be determined. With a combination two arrays, we showed that the direction and magnitude of the force can be determined by comparing the emission intensity change between two orthogonal arrays.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.