US 7,460,964 B2
Force vector reconstruction method using optical tactile sensor
Terukazu Mizota, Yamatokohriyama (Japan); Kazuto Kamiyama, Maebashi (Japan); Hiroyuki Kajimoto, Yokohama (Japan); Naoki Kawakami, Tokyo (Japan); and Susumu Tachi, Tsukuba (Japan)
Assigned to Toudai TLO, Ltd., Tokyo (Japan)
Appl. No. 10/571,371
PCT Filed Sep. 10, 2004, PCT No. PCT/JP2004/013203
§ 371(c)(1), (2), (4) Date Mar. 09, 2006,
PCT Pub. No. WO2005/029027, PCT Pub. Date Mar. 31, 2005.
Claims priority of application No. 2003-322627 (JP), filed on Sep. 16, 2003; and application No. 2004-177794 (JP), filed on Jun. 16, 2004.
Prior Publication US 2007/0043508 A1, Feb. 22, 2007
Int. Cl. G01L 1/06 (2006.01); G01L 7/02 (2006.01); G01L 11/02 (2006.01)
U.S. Cl. 702—41  [702/33; 702/138; 73/762; 73/800] 10 Claims
OG exemplary drawing
 
1. A force vector reconstruction method that uses an optical tactile sensor, said sensor having a tactile portion comprising a transparent elastic body and a plurality of marker groups provided in said body, each marker group being comprised of a number of colored markers, with markers constituting different marker groups having different colors for each group, said method comprising the steps of:
obtaining a marker image by taking an image of behavior of colored markers when an object contacts a contact surface of the elastic body;
obtaining information relating to the marker behavior from the marker image, said information being more than the number of force vectors to be obtained; and
obtaining force vectors as outputs by inputting said obtained information relating to the marker behavior to a transfer function,
wherein said obtaining force vectors comprises:
arranging one or more sampling points at a position where it is desired to obtain force vectors and arranging a plurality of sampling points around said position;
calculating force vectors acting at both the sampling points at said position and the sampling points around said position using information relating to marker behavior at and/or proximate to said position; and
adopting only force vectors acting at the sampling points at said position in the calculated force vectors and discarding force vectors acting at the sampling points around said position in the calculated force vectors.