Results 1  10
of
186
Nonholonomic motion planning: Steering using sinusoids
 IEEE fins. Auto. Control
, 1993
"... AbstractIn this paper, we investigate methods for steering systems with nonholonomic constraints between arbitrary configurations. Early work by Brockett derives the optimal controls for a set of canonical systems in which the tangent space to the configuration manifold is spanned by the input vec ..."
Abstract

Cited by 251 (15 self)
 Add to MetaCart
AbstractIn this paper, we investigate methods for steering systems with nonholonomic constraints between arbitrary configurations. Early work by Brockett derives the optimal controls for a set of canonical systems in which the tangent space to the configuration manifold is spanned by the input vector fields and their first order Lie brackets. Using Brockett’s result as motivation, we derive suboptimal trajectories for systems which are not in canonical form and consider systems in which it takes more than one level of bracketing to achieve controllability. These trajectories use sinusoids at integrally related frequencies to achieve motion at a given bracketing level. We define a class of systems which can be steered using sinusoids (chained systems) and give conditions under which a class of twoinput systems can be converted into this form. I.
Orienting Polygonal Parts without Sensors
, 1992
"... In manufacturing, it is often necessary to orient parts prior to packing or assembly. We say that a planar part is polygonal if its convex hull is a polygon. We consider the following problem: given a list of n vertices describing a polygonal part whose initial orientation is unknown, find the short ..."
Abstract

Cited by 207 (41 self)
 Add to MetaCart
In manufacturing, it is often necessary to orient parts prior to packing or assembly. We say that a planar part is polygonal if its convex hull is a polygon. We consider the following problem: given a list of n vertices describing a polygonal part whose initial orientation is unknown, find the shortest sequence of mechanical gripper actions that is guaranteed to orient the part up to symmetry in its convex hull. We show that such a sequence exists for any polygonal part by giving an O#n log n# algorithm for finding the sequence. Since the gripper actions do not require feedback, this result implies that any polygonal part can be oriented without sensors.
An Incremental SelfDeployment Algorithm for Mobile Sensor Networks
 AUTONOMOUS ROBOTS, SPECIAL ISSUE ON INTELLIGENT EMBEDDED SYSTEMS
, 2001
"... This paper describes an incremental deployment algorithm for mobile sensor networks. A mobile sensor network is a distributed collection of nodes, each of which has sensing, computation, communication and locomotion capabilities. The algorithm deploys nodes oneatatime into an unknown environment, ..."
Abstract

Cited by 165 (10 self)
 Add to MetaCart
This paper describes an incremental deployment algorithm for mobile sensor networks. A mobile sensor network is a distributed collection of nodes, each of which has sensing, computation, communication and locomotion capabilities. The algorithm deploys nodes oneatatime into an unknown environment, with each node making use of information gathered by previously deployed nodes to determine its target location. The algorithm is designed to maximize network `coverage' whilst simultaneously ensuring that nodes retain lineofsight with one another (this latter constraint arises from the need to localize the nodes; in our previous work on meshbased localization [12, 13] we have shown how nodes can localize themselves in a completely unknown environment by using other nodes as landmarks). This paper describes the incremental deployment algorithm and presents the results of an extensive series of simulation experiments. These experiments serve to both validate the algorithm and illuminate its empirical properties.
A Search Algorithm for Motion Planning with Six Degrees of Freedom
 ARTIFICIAL INTELLIGENCE
, 1987
"... The motion planning problem is of central importance to the fields of robotics, spatial planning, and automated design. In robotics we are interested in the automatic synthesis of robot motions, given highlevel specifications of tasks and geometric models of the robot and obstacles. The "Movers'" p ..."
Abstract

Cited by 75 (4 self)
 Add to MetaCart
The motion planning problem is of central importance to the fields of robotics, spatial planning, and automated design. In robotics we are interested in the automatic synthesis of robot motions, given highlevel specifications of tasks and geometric models of the robot and obstacles. The "Movers'" problem is to find a continuous, collisionfree path for a moving object through an environment containing obstacles. We present an implemented algorithm for the classical formulation of the threedimensional Movers' problem: Given an arbitrary rigid polyhedral moving object P with three translational and three rotational degrees of freedom, find a continuous, collisionfree path taking P from some initial configuration to a desired goal configuration. This paper describes an implementation of a complete algorithm (at a given resolution)for the full six degree of freedom Movers' problem. The algorithm transforms the six degree of freedom planning problem into a point navigation problem in a sixdimensional configuration space (called Cspace). The Cspace obstacles, which characterize the physically unachievable configurations, are directly represented by sixdimensional manifolds whose boundaries are fivedimensional Csurfaces. By characterizing these surfaces and their intersections, collisionfree paths may be found by the
On Geometric Assembly Planning
, 1992
"... This dissertation addresses the problem of generating feasible assembly sequences for a mechanical product from a geometric model of the product. An operation specifies a motion to bring two subassemblies together to make a larger subassembly. An assembly sequence is a sequence of operations that co ..."
Abstract

Cited by 71 (12 self)
 Add to MetaCart
This dissertation addresses the problem of generating feasible assembly sequences for a mechanical product from a geometric model of the product. An operation specifies a motion to bring two subassemblies together to make a larger subassembly. An assembly sequence is a sequence of operations that construct the product from the individual parts. I introduce the nondirectional blocking graph, a succinct characterization of the blocking relationships between parts in an assembly. I describe efficient algorithms to identify removable subassemblies by constructing and analyzing the NDBG. For an assembly A of n parts and m partpart contacts equivalent to k contact points, a subassembly that can translate a small distance from the rest of A can be identified in O(mk 2 ) time. When rotations are allowed as well, the time bound is O(mk 5 ). Both algorithms are extended to find connected subassemblies in the same time bounds. All free subassemblies can be identified in outputdependent ...
Information Invariants for Distributed Manipulation
, 1995
"... In (Donald, 1995), we described a manipulation task for cooperating mobile robots that can push large, heavy objects. There, we asked whether explicit local and global communication between the agents can be removed from a family of pushing protocols. In this paper, we answer in the affirmative. We ..."
Abstract

Cited by 67 (16 self)
 Add to MetaCart
In (Donald, 1995), we described a manipulation task for cooperating mobile robots that can push large, heavy objects. There, we asked whether explicit local and global communication between the agents can be removed from a family of pushing protocols. In this paper, we answer in the affirmative. We do so by using the general methods of (Donald, 1995) analyzing information invariants. We discuss several measures for the information complexity of the task: (a) How much internal state should the robot retain? (b) How many cooperating agents are required, and how much communication between them is necessary? (c) How can the robot change (sideeffect) the environment in order to record state or sensory information to perform a task? (d) How much information is provided by sensors? and (e) How much computation is required by the robot? To answer these questions, we develop a notion of information invariants. We develop a technique whereby one sensor can be constructed from others by adding...
LandmarkBased Robot Navigation
 Algorithmica
, 1992
"... Achieving goals despite uncertainty in control and sensing may require robots to perform complicated motion planning and execution monitoring. This paper describes a reduced version of the general planning problem in the presence of uncertainty and a complete polynomial algorithm solving it. The pla ..."
Abstract

Cited by 58 (3 self)
 Add to MetaCart
Achieving goals despite uncertainty in control and sensing may require robots to perform complicated motion planning and execution monitoring. This paper describes a reduced version of the general planning problem in the presence of uncertainty and a complete polynomial algorithm solving it. The planner computes a guaranteed plan (for given uncertainty bounds) by backchaining omnidirectional backprojections of the goal until one fully contains the set of possible initial positions of the robot. The algorithm assumes that landmarks are scattered across the workspace, that robot control and position sensing are perfect within the fields of influence of these landmarks (the regions in which the landmarks can be sensed by the robot), and that control is imperfect and sensing null outside these fields. The polynomiality and completeness of the algorithm derive from these simplifying assumptions, whose satisfaction may require the robot and/or its workspace to be specifically engineered. Thi...
Challenges for Complete Creature Architectures
 In
, 1990
"... In recent years there has been a move within the artificial intelligence and robotics communities towards building complete autonomous creatures that operate in the physical world. Certain approaches have proven quite successful, and have caused a reanalysis within the field of artificial intellige ..."
Abstract

Cited by 57 (2 self)
 Add to MetaCart
In recent years there has been a move within the artificial intelligence and robotics communities towards building complete autonomous creatures that operate in the physical world. Certain approaches have proven quite successful, and have caused a reanalysis within the field of artificial intelligence of what components are necessary in the intellectual architecture of such creatures. However nothing built thus far yet comes close the dreams that many people hold dearly. Furthermore there has been quite some criticism of the new approaches for lacking adequate theoretical justification. In this paper we outline some of the more obvious challenges that remain for these new approaches, and suggest new ways of thinking about the tasks ahead, in order to decompose the field into a number of manageable subareas that can be used to shape further research. 1 Introduction There is a growing interest in building artificial creatures of some sort. One example is the recent boom in a field kn...
Motion planning: A journey of robots, molecules, digital actors, and other artifacts
 International Journal of Robotics Research
, 1999
"... During the last three decades motion planning has emerged as a crucial and productive research area in robotics. In the mid80's the most advanced planners were barely able to compute collisionfree paths for objects crawling in planar workspaces. Today, planners e ciently deal with robots with many ..."
Abstract

Cited by 56 (3 self)
 Add to MetaCart
During the last three decades motion planning has emerged as a crucial and productive research area in robotics. In the mid80's the most advanced planners were barely able to compute collisionfree paths for objects crawling in planar workspaces. Today, planners e ciently deal with robots with many degrees of freedom in complex environments. Techniques also exist to generate quasioptimal trajectories, coordinate multiple robots, deal with dynamic and kinematic constraints, and handle dynamic environments. This paper describes some of these achievements, presents new problems that have recently emerged, discusses applications likely to motivate future research, and nally gives expectations for the coming years. It stresses the fact that nonrobotics applications (e.g., graphic animation, surgical planning, computational biology) are growing in importance and are likely to shape future motion planning research more than robotics itself. 1
Inductive Learning of Reactive Action Models
 Proceedings of the Twelfth International Conference on Machine Learning
, 1995
"... An important area of learning in autonomous agents is the ability to learn domainspecific models of actions to be used by planning systems. In this paper, we present methods by which an agent learns action models from its own experience and from its observation of a domain expert. These methods dif ..."
Abstract

Cited by 54 (1 self)
 Add to MetaCart
An important area of learning in autonomous agents is the ability to learn domainspecific models of actions to be used by planning systems. In this paper, we present methods by which an agent learns action models from its own experience and from its observation of a domain expert. These methods differ from previous work in the area in two ways: the use of an action model formalism which is better suited to the needs of a reactive agent, and successful implementation of noisehandling mechanisms. Training instances are generated from experience and observation, and a variant of GOLEM is used to learn action models from these instances. The integrated learning system has been experimentally validated in simulated construction and office domains. 1 INTRODUCTION Autonomous agents acting in complex environments must be capable of learning from experience, both to avoid the need for exhaustive preprogramming and to adapt to unanticipated or changing situations. Most such work has focused o...