摘要:

AbstractDextrous hand designs require planning and coordination of multijointed fingers. This communication presents a dynamic programming algorithm to optimize the trajectory of a finger or a fingerlike manipulator. The algorithm generates a minimum cost trajectory for a specified cost function (such as accuracy or time of travel) and a set of constraints (such as obstacles along the trajectory). We present simulations demonstrating the trajectory planning for simplified fingerlike manipulator configurations. This approach is potentially applicable to several additional situations faced by multijointed fingers employed in dextrous hand designs, such as complex trajectory planning, obstacle avoidance, and fault tolerance. We illustrate some results obtained by computer simulations of these problems.

ISSN:0741-2223    

DOI:10.1002/rob.4620040302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractAn intelligent, adaptive robotic system is being developed for a low‐volume, high precision process: the welding of the Space Shuttle Main Engines (SSMEs). The overall system goals include the development of a workstation‐based system to provide flexible, efficient off‐line programming of both motion and welding process commands for the robotic workcell. This offline programming system includes: implementation of a user interface for weld engineers, generation of both geometric and process commands for the workcell, development of a weld parameter database system, and display of both run‐time and archived data. This article presents details of the off‐line programming system, including interfaces, implementation, and limitations. The system will be implemented on the SSME production floor, and will be benchmarked in effectiveness and productivity against commercially available robotic welding systems presently in use. The overall system development is a joint effort between NASA's Marshall Space Flight Center and two divisions of Rockwell International: Rocketdyne and the Scien

ISSN:0741-2223    

DOI:10.1002/rob.4620040303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe control problem for a two‐arm robotic system in coordinated motion is addressed. A hierarchical framework, employing two levels of control hierarchy, is utilized, and the decentralized model reference adaptive control approach using variable structure controllers (DMRA‐VSC) is applied. Within the control hierarchy, the DMRA‐VSC strategy is accomplished at the lower level, where control is responsible for the servoing of each joint. These local controllers are coordinated by the high‐level, central controller, whose task is to provide the local controllers with the upper bound on the dynamical interactions with other subsystems. The local controllers are responsible for making each link follow the prescribed local reference subsystem in moving from one position to another. This is done using the local measurements and the information provided by the central controller. Advantages of the DMRA‐VSC approach for multiple manipulator control include the inherent robustness properties to nonlinearities and interaction effects, the decentralization structure facilitating ease in multiple manipulator system programming and implementation, and the general structure of the controller which allows further extensions such as force

ISSN:0741-2223    

DOI:10.1002/rob.4620040304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe authors propose a method for the determination of singularities in motion and displacement functions for a seven degree‐of‐freedom manipulator. The manipulator is considered, hereby, as a set of six degree‐of‐freedom manipulators. It is proven that two types of singularities in motion can occur at link positions that are independent and dependent with respect to the trajectory to be executed. The relations between the structure of singularity equations and displacement equations are discussed. The derivation of displacement equations for a manipulator with singularities of the second type is based on the idea of modeling of a manipulator by two open kinematic chains and invariants that may be found for these chains. The inverse kinematic equations and the equations of singularities in motion have been derived using a symbolic computer program which can handle manipulators of general structure (with five, six, and seven degrees‐of‐freedom). This program is written in the Symbolic Computation Lang

ISSN:0741-2223    

DOI:10.1002/rob.4620040305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe objective of this article is to present a novel approach to object recognition and classification for robotic applications using the automated decision tree generation technique. The method developed relies upon simple statistical measurements extracted from object classes and represented in the form of a distance matrix ‘D’ to form a decision tree. The algorithms presented here are computationally efficient and simple to implement. The effectiveness of the features are automatically assessed, allowing for the automatic selection of only those features needed to accomplish object recognition and classification. The performance of the algorithms are successfully tested and demonstra

ISSN:0741-2223    

DOI:10.1002/rob.4620040306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractAlthough a variety of formulation schemes for the dynamic equations of robot manipulators with rigid links can be found in the literature, an efficient method of the formulation for robot manipulators with elastic links is not well known. Accordingly, this work presents the derivation of the equations of motion for application to mechanical manipulators with elastic links. The formulation is conducted analytically using Hamilton's principle. The resultant equations consist of the terms of inertial, Coriolis, centrifugal, gravitational, and exerted forces. They are expressed in terms of a set of independent generalized coordinates. In contrast to conventional variational approaches, the present method provides an efficient and systematic way for obtaining the compact symbolic equations of flexible manipulator systems. Two examples are presented to illustrate the proposed methodology. Firstly, a three‐link flexible manipulator with three revolute joints is studied. A flexible manipulator consisting of a prismatic joint and a discrete mass is the second mode

ISSN:0741-2223    

DOI:10.1002/rob.4620040307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0741-2223    

DOI:10.1002/rob.4620040301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY