Efficient visual grasping alignment for cylindersMonocular information from a gripper-mounted camera is used to servo the robot gripper to grasp a cylinder. The fundamental concept for rapid pose estimation is to reduce the amount of information that needs to be processed during each vision update interval. The grasping procedure is divided into four phases: learn, recognition, alignment, and approach. In the learn phase, a cylinder is placed in the gripper and the pose estimate is stored and later used as the servo target. This is performed once as a calibration step. The recognition phase verifies the presence of a cylinder in the camera field of view. An initial pose estimate is computed and uncluttered scan regions are selected. The radius of the cylinder is estimated by moving the robot a fixed distance toward the cylinder and observing the change in the image. The alignment phase processes only the scan regions obtained previously. Rapid pose estimates are used to align the robot with the cylinder at a fixed distance from it. The relative motion of the cylinder is used to generate an extrapolated pose-based trajectory for the robot controller. The approach phase guides the robot gripper to a grasping position. The cylinder can be grasped with a minimal reaction force and torque when only rough global pose information is initially available.
Document ID
19930043020
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Nicewarner, Keith E. (NASA Headquarters Washington, DC United States)
Kelley, Robert B. (Rensselaer Polytechnic Inst. Troy, NY, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: Cooperative intelligent robotics in space II; Proceedings of the Meeting, Boston, MA, Nov. 12-14, 1991 (A93-27001 09-54)
Publisher: Society of Photo-Optical Instrumentation Engineers