A complete algorithm for designing passive fences to orient parts

Wiegley, Jeff; Goldberg, Ken; Peshkin, M.; Brokowski, Mike

doi:10.1109/robot.1996.506860

Cited by 53 publications

(36 citation statements)

References 14 publications

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“…Later, Brokowski et al [4] constrained the part to one of Ç´Ñµ orientations by adding a curved tail to each fence. This led to the complete algorithm of Wiegley et al [15], which allows for all possible fence angles and is guaranteed to find a sequence of fences to orient a part if one exists. They conjecture that a polynomialtime fence-design algorithm exists for any polygonal part.…”

Section: Figmentioning

confidence: 99%

A Near-Quadratic Algorithm for Fence Design

Agarwal

Berretty

Collins

2004

Springer Tracts in Advanced Robotics

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Abstract.A part feeder is a mechanism that receives a stream of identical parts in arbitrary orientations and outputs them oriented the same way. Various sensorless part feeders have been proposed in the literature. The feeder we consider consists of a sequence of fences that extend partway across a conveyor belt; a polygonal part È carried by the belt is reoriented by each fence it encounters. We present an Ç´Ñ · Ò ¾ ÐÓ ¿ Òµ-time algorithm to compute a sequence of fences that uniquely orients È , if one exists, where Ñ is the total number of vertices and Ò is the number of stable edges of È . As in [3], we reduce the problem to searching for a path in a state graph that has Ç´Ò ¿ µ edges. By exploiting various geometric properties of the state graph, we show that it can be represented implicitly and a desired path can be found in Ç´Ñ · Ò ¾ ÐÓ ¿ Òµ time. Our technique is quite general and is applicable to other part manipulation problems.

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Section: Figmentioning

confidence: 99%

A Near-Quadratic Algorithm for Fence Design

Agarwal

Berretty

Collins

2004

Springer Tracts in Advanced Robotics

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“…In his Ph.D. thesis (Mason, 1982(Mason, , 1985 nonprehensile manipulation takes the form of pushing an object in the plane to reduce uncertainty about the object's pose. Subsequent work by others showed how to use pushing to design fences for a conveyor belt system (Peshkin and Sanderson, 1988;Wiegley et al, 1996) and how to plan paths for pushing objects among obstacles (Lynch, 1997). Lynch et al (1998) showed how to make a robotic manipulator perform a certain juggling motion with a suitable parameterization of the shape and motion of the manipulator.…”

Section: Nonprehensile Manipulationmentioning

confidence: 99%

Reconstructing shape from motion using tactile sensors

Moll

Erdmann

2001

Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics I

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We present a new method to reconstruct the shape of an unknown object using tactile sensors without requiring object immobilization. Instead, the robot manipulates the object without prehension. The robot infers the shape, motion and center of mass of the object based on the motion of the contact points as measured by tactile sensors. Our analysis is supported by simulation and experimental results.

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“…It has been noted 5,20] that nding a sequence of fences is equivalent to nding a sequence of push actions under the constraint that every reorientation of the jaw imposes a restriction on the next reorientation. In other words, the previous push angle o set restricts the next o set.…”

Section: Equilibrium Push Directions and Part Eccentricitymentioning

confidence: 99%

Geometric Eccentricity and the Complexity of Manipulation Plans

2000

Self Cite

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Complexity bounds for algorithms for robotic motion and manipulation can be misleading when they are constructed with pathological`worst-case' scenarios that rarely appear in practice. Complexity can in some cases be reduced by c haracterizing nonpathological objects in terms of intuitive geometric properties. In this paper we consider the number of push and push-squeeze actions needed to orient a part without sensors and improve on the upper bound of O(n) for polygonal parts given by Chen and Ierardi in 9]. We de ne the geometric eccentricity of a planar part based on the aspect ratio of a distinguished bounding box. We s h o w t h a t o n l y O(1) actions are required for parts with non-zero eccentricity. The analysis also applies to curved parts, providing the rst complexity bound for non-polygonal parts. Our results also yield new bounds on part feeders that use fences and conveyor belts.

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A complete algorithm for designing passive fences to orient parts

Cited by 53 publications

References 14 publications

A Near-Quadratic Algorithm for Fence Design

A Near-Quadratic Algorithm for Fence Design

Reconstructing shape from motion using tactile sensors

Geometric Eccentricity and the Complexity of Manipulation Plans

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