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In general, any object can be restricted or caged within a bounded region if we evenly place a sufficient number of fingers around the object. This naive approach often leads to inefficient utilization of fingers because only two fingers are sufficient to cage most nonconvex objects. In this paper, we propose an algorithm that identifies all the caging sets, i.e., set of two-finger placements that...
We consider the task of grasping novel objects and cleaning fairly cluttered tables with many novel objects. Recent successful approaches employ machine learning algorithms to identify points on the scene that the robot should grasp. In this paper, we show that the task can be significantly simplified by using segmentation, especially with depth information. A supervised localization method is employed...
This work proposes a necessary condition for n-finger force closure grasp which considers true quadratic force cone without linearization. The condition finds its use as a heuristic for multiple queries force closure test. The heuristic works as a filtering criteria which improves the overall running time of the entire set of queries. An empirical example shows that our approach could speed up the...
We propose a heuristic approach for a regrasp planning problem. The input with a large number of discrete contact points is considered. In this setting, traditional methods of complete solution is not available. Based on wrench space information of the input, our proposed algorithm clusters the input into groups and chooses a representative contact point from each group. A global graph structure for...
This paper proposes an implementation of Fast-SLAM for localization and mapping for an indoor environment. The system use only the bearing information retrieved from an omnidirectional camera via vertical line segments which are common in an indoor environment. The real world experiment is also presented using Pioneer-DX3 mobile robot moving in a room with several objects.
Programmable force field, as a generalized supporting concept for universal part feeder, has been researched and developed for decades. A variety of fields has been proposed, most focused to the fewest possible part positions and orientations. However, there are more factors needed to be concerned in practical use, such as time consumed for part manipulation, or ability of the actual devices to create...
The formation control problem is one of fundamental problems in multi-robot applications, such as exploration and mapping. In this paper, we present a distributed formation control algorithm for a group of mobile robots moving in a obstacle filled workspace. The algorithm is based on the concept of a spring force and a potential filed. Our algorithm works under limited sensory information and require...
The object caging problem focuses on designing a formation of fingers that keeps an object within a bounded space without immobilizing it. This paper addresses the problem of designing such formation for object represented by a polytope in any finite dimensional workspace and for any specified number of pointed finger. Our goal is to characterize all the caging sets, each of which corresponds to a...
This paper addresses the problem of optimizing the maximal independent contact region for two-fingered force- closure grasp of a rigid object in 2D. Existing methods for optimizing this criterion considered only independent graspable regions on a given pair of edges. We propose an algorithm that takes nearby edges into consideration so that larger independent contact regions can be obtained. Our method...
Coverage control without global information is a fundamental problem in multi-robot mapping and exploration applications. In this paper, we propose a coverage control algorithm for a heterogeneous group of robots which imposed area constraints. A distributed control algorithm for covering specific area according to observable heterogeneity is presented The algorithm is based on the concept of a centroidal...
An object is said to be caged when it is bounded within some confined workspace, in which it may move but cannot escape from. An object in a cage formed by multiple robots can be transported as the robot caging formation moves. Unlike traditional contact based approach, this non-prehensile transportation strategy puts much less stringent requirement on robot synchronization and object dynamics prediction...
We propose a heuristic approach for regrasp planning problem. We consider especially the case when the input is a triangular mesh with a large number of facets. In such setting, traditional method of complete solution is not available. Our method provides trade off between completeness and resource used in the computation. The algorithm simplifies the input using well known triangular mesh simplification...
We consider a 3D grasping problem. We propose a test of Ropf3-positive span of force cones and a test of Ropf3-positive span of their torque set. Our methods consider directly the quadratic force cone without pyramidal linearization of a cone. The conditions can be computed in a constant time and they are used as a heuristic for 3D force closure test. We also show that our proposed heuristic greatly...
The problem of object caging is defined as a problem of designing a formation of fingers to restrict an object within a bounded space. Assuming two pointed fingers and a rigid polygonal or polyhedral object, this paper addresses the problem of two-finger squeezing caging, i.e., to characterize all possible formations of the fingers that are capable of caging the object via limiting their separation...
Controlling and coordinating multiple robots to form a desired pattern is a fundamental problem in multi-robot systems. In this paper, we study the problem of pattern formation for a heterogenous group of robots. A distributed control algorithm for forming a multi-layered circular shell without explicit robot communication is presented. The algorithm is based on the concept of artificial force field...
This paper investigates the use of various optimization algorithms for solving the problem of planning optimal three-finger force-closure grasps on curved objects. The optimization aims at minimizing the Q distance function which had been shown in the literature to directly reflect quality of grasps and possess function's smoothness suitable for optimization processes. Four optimization methods including...
For a set of n contact points on the boundary of a 2D object together with their contact normals, we present an output sensitive algorithm for computing all of combinations of four points from this set that achieve force closure under the frictionless contact assumption. The proposed algorithm runs in O(n3 lg2 n + K) where K is the number of unique solutions. Preliminary implementation is described...
This paper formalizes and proposes an algorithm to compute coverage diameters of polygons in 2D. Roughly speaking, the coverage diameter of a polygon is the longest possible distance between two points through which the polygon cannot pass in between. The primary use of coverage diameter is to form a cage for transporting an object, not necessarily convex, with multiple disc-shaped robots. The main...
An object is captured by a set of fingers when there exists no trajectory to bring the object arbitrarily far from the fingers. Object concavity is a special geometric property that allows objects to be captured with only few fingers. In particular, certain concave objects may be captured by appropriately placing two fingers close to some pair of opposite concave sections. This paper addresses the...
Abstract. This paper addresses the problem of grasping and manipulating three-dimensional objects with a reconfigurable gripper that consists of two parallel plates whose distance can be adjusted by a computer-controlled actuator. The bottom plate is a bare plane, and the top plate carries a rectangular grid of actuated pins that can translate in discrete increments under computer control. We propose...
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