Manipulating Parts with an Array of Pins: A Method and a Machine
- 1 October 2001
- journal article
- others
- Published by SAGE Publications in The International Journal of Robotics Research
- Vol. 20 (10), 808-818
- https://doi.org/10.1177/02783640122068119
Abstract
This article investigates the manipulation of polygonal parts using a simple device consisting of a grid of retractable pins mounted on a vertical plate. This “Pachinko machine” is intended as a reconfigurable parts feeder for flexible assembly. A part dropped on this device may come to rest on the actuated pins, bounce out, or fall through. The authors propose a novel algorithm for part reorientation. Its input consists of the shape of a part, its initial position and orientation, and a goal configuration, and its output is a sequence of pin actuations that will bring the part to the goal configuration. The proposed approach does not attempt to predict the part motion between the equilibria associated with the active pins in the output sequence; instead, it constructs the capture region of each equilibrium (i.e., the maximal subset of the part’s configuration space such that any motion starting within it is guaranteed to end at the equilibrium). Assuming frictionless contacts and dissipative dynamics, reorienting a part reduces to finding a path from initial to goal states in a directed graph whose nodes are the equilibria and whose arcs link pairs of nodes such that the first equilibrium lies in the capture region of the second one. The proposed approach has been implemented on a prototype of the Pachinko machine, and initial experiments are presented.Keywords
This publication has 20 references indexed in Scilit:
- Grasping and In-Hand Manipulation: Geometry and AlgorithmsAlgorithmica, 2000
- Let Them Fall Where They May: Capture Regions of Curved Objects and PolyhedraThe International Journal of Robotics Research, 1997
- A complete algorithm for designing passive fences to orient partsAssembly Automation, 1997
- Geometric Sensing of Known Planar ShapesThe International Journal of Robotics Research, 1996
- Complete algorithms for feeding polyhedral parts using pivot graspsIEEE Transactions on Robotics and Automation, 1996
- On the geometry of contact formation cells for systems of polygonsIEEE Transactions on Robotics and Automation, 1995
- Orienting polygonal parts without sensorsAlgorithmica, 1993
- Automatic Grasp Planning in the Presence of UncertaintyThe International Journal of Robotics Research, 1988
- Planning robotic manipulation strategies for workpieces that slideIEEE Journal on Robotics and Automation, 1988
- Automatic Synthesis of Fine-Motion Strategies for RobotsThe International Journal of Robotics Research, 1984