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70
Pathplanning strategies for a point mobile automaton moving amidst unknown obstacles of arbitrary shape
 ALGORITHMICA
, 1987
"... The problem of path planning for an automaton moving in a twodimensional scene filled with unknown obstacles is considered. The automaton is presented as a point; obstacles can be of an arbitrary shape, with continuous boundaries and of finite size; no restriction on the size of the scene is impos ..."
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Cited by 163 (3 self)
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The problem of path planning for an automaton moving in a twodimensional scene filled with unknown obstacles is considered. The automaton is presented as a point; obstacles can be of an arbitrary shape, with continuous boundaries and of finite size; no restriction on the size of the scene is imposed. The information available to the automaton is limited to its own current coordinates and those of the target position. Also, when the automaton hits an obstacle, this fact is detected by the automaton's "'tactile sensor. " This information is shown to be sufficient for reaching the target or concluding in finite time that the target cannot be reached. A worstcase lower bound on the length of paths generated by any algorithm operating within the framework of the accepted model is developed; the bound is expressed in terms of the perimeters of the obstacles met by the automaton in the scene. Algorithms that guarantee reaching the target (if the target is reachable), and tests for target reachability are presented. The efficiency of the algorithms is studied, and worstcase upper bounds on the length of generated paths are produced.
RealTime Inverse Kinematics Techniques for Anthropomorphic Limbs
 Graphical Models
, 2000
"... this paper we develop a set of inverse kinematics algorithms suitable for an anthropomorphic arm or leg. We use a combination of analytical and numerical methods to solve generalized inverse kinematics problems including position, orientation, and aiming constraints. Our combination of analytical ..."
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Cited by 141 (3 self)
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this paper we develop a set of inverse kinematics algorithms suitable for an anthropomorphic arm or leg. We use a combination of analytical and numerical methods to solve generalized inverse kinematics problems including position, orientation, and aiming constraints. Our combination of analytical and numerical methods results in faster and more reliable algorithms than conventional inverse Jacobian and optimizationbased techniques. Additionally, unlike conventional numerical algorithms, our methods allow the user to interactively explore all possible solutions using an intuitive set of parameters that define the redundancy of the system. c 2000 Academic Press Key Words: inverse kinematics; realtime IK; human arm kinematics; analytical algorithms
Planning Motions with Intentions
, 1994
"... We apply manipulation planning to computer animation. A new path planner is presented that automatically computes the collisionfree trajectories for several cooperating arms to manipulate a movable object between two configurations. This implemented planner is capable of dealing with complicated ta ..."
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Cited by 135 (17 self)
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We apply manipulation planning to computer animation. A new path planner is presented that automatically computes the collisionfree trajectories for several cooperating arms to manipulate a movable object between two configurations. This implemented planner is capable of dealing with complicated tasks where regrasping is involved. In addition, we present a new inverse kinematics algorithm for the human arms. This algorithm is utilized by the planner for the generation of realistic human arm motions as they manipulate objects. We view our system as a tool for facilitating the production of animation.
An Intelligent Predictive Control Approach to the HighSpeed CrossCountry Autonomous Navigation Problem
, 1995
"... mRIm9533 submitted in partial fulfiumtnr of the reqimlmts for the degm of ..."
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Cited by 75 (3 self)
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mRIm9533 submitted in partial fulfiumtnr of the reqimlmts for the degm of
Efficient Inverse Kinematics for General 6R Manipulators
 IEEE Transactions on Robotics and Automation
, 1994
"... The inverse kinematics of serial manipulators is a central problem in the automatic control of robot manipulators. The main interest has been in inverse kinematics of a six revolute (6R) jointed manipulator with arbitrary geometry. It has been recently shown that the joints of a general 6R manipula ..."
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Cited by 47 (1 self)
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The inverse kinematics of serial manipulators is a central problem in the automatic control of robot manipulators. The main interest has been in inverse kinematics of a six revolute (6R) jointed manipulator with arbitrary geometry. It has been recently shown that the joints of a general 6R manipulator can orient themselves in 16 different configurations (at most), for a given pose of the endeffector. However, there are no good practical solutions available, which give a level of performance expected of industrial manipulators. In this paper, we present an algorithm and implementation for efficient inverse kinematics for a general 6R manipulator. When stated mathematically, the problem reduces to solving a system of multivariate equations. We make use of the algebraic properties of the system and the symbolic formulation used for reducing the problem to solving a univariate polynomial. However, the polynomial is expressed as a matrix determinant and its roots are computed by reducin...
The CMU Reconfigurable Modular Manipulator System
 TECHNICAL REPORT
, 1988
"... Modular manipulator designs have long been b een considered for use as research tools, and as the basis for easily
modified industrial manipulators. In these manipulators the links and joints are discrete and modular components
that can be assembled into a desired manipulator configuration. As ha ..."
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Cited by 42 (14 self)
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Modular manipulator designs have long been b een considered for use as research tools, and as the basis for easily
modified industrial manipulators. In these manipulators the links and joints are discrete and modular components
that can be assembled into a desired manipulator configuration. As hardware advances have made actual modular
manipulators practical, various capabilities of such manipulators have gained interest. Particularly desirable is the
ability to rapidly reconfigure such a manipulator, in order to custom tailor i t to specific tasks. T i reconfiguration
hs
greatly enhances the capability of a given amount of manipulator hardware. This paper discusses the development of
a prototype modular manipulator and the implementation of a configuration independent manipulator kinematics
algorithm used for path planning in the prototype.
On the Generation of Smooth ThreeDimensional Rigid Body Motions
, 1995
"... This paper addresses the problem of generating smooth trajectories between an initial and a final position and orientation in space. The main idea is to define a functional depending on velocity or its derivatives that measures the smoothness of a trajectory and find trajectories that minimize this ..."
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Cited by 30 (9 self)
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This paper addresses the problem of generating smooth trajectories between an initial and a final position and orientation in space. The main idea is to define a functional depending on velocity or its derivatives that measures the smoothness of a trajectory and find trajectories that minimize this functional. In order to ensure that the computed trajectories are independent of the parameterization of positions and orientations, we use the notions of Riemannian metric and covariant derivative from differential geometry and formulate the problem as a variational problem on the Lie group of spatial rigid body displacements, SE(3). We show that by choosing an appropriate measure of smoothness, the trajectories can be made to satisfy boundary conditions on the velocities or higher order derivatives. Dynamically smooth trajectories can be obtained by incorporating the inertia of the system into the definition of the Riemannian metric. We state the necessary conditions for the shortest dista...
Conformational analysis of molecular chains using nanokinematics
 Computer Application of Biological Sciences (CABIOS
, 1995
"... Abstract: We present algorithms for 3D manipulation and conformational analysis of molecular chains, when bond length, bond angles and related dihedral angles remain xed. These algorithms are useful for local deformations of linear molecules, exact ring closure in cyclic molecules and molecular emb ..."
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Cited by 26 (2 self)
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Abstract: We present algorithms for 3D manipulation and conformational analysis of molecular chains, when bond length, bond angles and related dihedral angles remain xed. These algorithms are useful for local deformations of linear molecules, exact ring closure in cyclic molecules and molecular embedding for short chains. Other possible applications include structure prediction, protein folding, conformation energy analysis and 3D molecular matching and docking. The algorithms are applicable to all serial molecular chains and make no asssumptions about their geometry. We make use of results on direct and inverse kinematics from robotics and mechanics literature and show the correspondence between kinematics and conformational analysis of molecules. In particular, we pose these problems algebraically and compute all the solutions making use of the structure of these equations and matrix computations. The algorithms have been implemented and perform well in practice. In particular, they take tens of milliseconds on current workstations for local deformations and chain closures on molecular chains consisting of six or fewer rotatable dihedral angles.
Solving mechanics problems using metalevel inference
 In 6th. Int'l Joint Conference on Artificial Intelligence
, 1979
"... which solves a wide range of mechanics problems from statements in both predicate calculus and English. Mecho uses the technique of metalevel inference to control search in natural language understanding, common sense inference, model formation and algebraic manipulation. We argue that this is a po ..."
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Cited by 24 (3 self)
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which solves a wide range of mechanics problems from statements in both predicate calculus and English. Mecho uses the technique of metalevel inference to control search in natural language understanding, common sense inference, model formation and algebraic manipulation. We argue that this is a powerful technique for controlling search while retaining the modularity of declarative knowledge representations.
Geometric Problems in Molecular Biology and Robotics
 INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEMS FOR MOLECULAR BIOLOGY
, 1994
"... Some of the geometric problems of interest to molecular biologists have macroscopic analogues in the field of robotics. Two examples of such analogies are those between protein docking and modelbased perception, and between ring closure and inverse kinematics. Molecular dynamics simulation, too, ha ..."
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Cited by 20 (0 self)
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Some of the geometric problems of interest to molecular biologists have macroscopic analogues in the field of robotics. Two examples of such analogies are those between protein docking and modelbased perception, and between ring closure and inverse kinematics. Molecular dynamics simulation, too, has much in common with the study of robot dynamics. In this paper we give a brief survey of recent work on these and related problems.