ISSN:0741-2223    

DOI:10.1002/rob.4620040102

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

年代:1987

数据来源: WILEY

摘要:

AbstractA number of methods have been proposed for the control of kinematically redundant manipulators, that is, those with more than the minimum number of degrees of freedom. This article uses a dynamic simulation to test whether proposed schemes should, in fact, work well when the dynamics of the actual system are considered. In order to perform a realistic simulation, a nine‐degree‐of‐freedom arm has been designed using commercially available motors. The simulation shows the effects that specifying a secondary goal has on the satisfaction of the primary goal. Also shown is the dependence of servo performance on modeling the

ISSN:0741-2223    

DOI:10.1002/rob.4620040103

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis article describes an approach for modeling the work cycle of robotized manufacturing cells. The approach incorporates the logic of GERT networks and the computational techniques of recursion models, but extends these fundamental concepts to provide a resource‐based model of cell operations. Since the approach gives approximate estimates of performance, accuracy is evaluated in comparison with simulation results. A comprehensive, but hypothetical, example is given to describe use of the model as an aid in cell design. Typical applications involve “what if” studies to evaluate end‐of‐arm effectors, cell layout, a limited supply of tooling, equipment capabilities (e.g., speeds), and sequence of operations in cells employing one or mo

ISSN:0741-2223    

DOI:10.1002/rob.4620040104

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

年代:1987

数据来源: WILEY

摘要:

AbstractWe consider problems associated with the coordination of movement within a multiple‐robot system in which all motion is restricted to a single track. Our objective is to minimize the reconfiguration time, that is, the total time required to move a collection of robots from an initial to a goal configuration. We show that various models give rise to a wide range of problem complexities. For these problems we design and analyze optimization and approximation strategie

ISSN:0741-2223    

DOI:10.1002/rob.4620040105

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

年代:1987

数据来源: WILEY

摘要:

AbstractA structural finite‐element technique based on Bernoulli‐Euler beam theory is presented which will permit the finding of the torques (or forces) that are necessary to apply at one end of a flexible link to produce a desired motion at the other end. This technique is suitable for the open loop control of the tip motion. It may also provide a good control law for feedback control. The finite‐element method is used to discretize the equations of motion. This method has a major advantage in the fact that different material properties and boundary conditions like hubs, tip loads, changes in cross sections, etc., can be handled in a very simple and straightforward manner. The resulting differential equations are integrated via the frequency domain. This allows for the expansion of the desired end motion into its harmonic components and helps to visualize the complex wave propagation nature of the problem. The performance of the proposed technique is illustrated in the solution of a practical example. Results point out the potential that this technique has in the study of the dynamics and control not only of flexible robots, but also of any other flexible mechanisms like those used in biomechanics, where high precision at the tip of very light flexible arms is req

ISSN:0741-2223    

DOI:10.1002/rob.4620040106

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

年代:1987

数据来源: WILEY

摘要:

AbstractA generalized model that goes beyond the usual assumption of “ideal” joint behavior is proposed. The “real” joint has five ancillary degrees of freedom besides the dominant motion. The resulting manipulator transformation with its greater degree of sophistication is expected to help in calibration and compensation of the various kinematic contributions to robot inaccuracy. The procedure to compute this generalized manipulator transformation is presented. The generalized model also results in manipulator differential relationships and these are di

ISSN:0741-2223    

DOI:10.1002/rob.4620040107

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

年代:1987

数据来源: WILEY

摘要:

AbstractNonlinear feedback controlalgorithms for manipulators utilize a complete (coupled and nonlinear) dynamic robot model to decouple the robot joints. In the companion article1we outlined the practical problems introduced by modeling inaccuracies, unmodeled dynamics and parameter errors. We then introduced the α‐computed‐torquenonlinear feedback control algorithm which isrobustin the presence of the aforementioned error sources. In this article, we apply the insight gained from the α‐computed‐torque algorithm to design a robust discrete‐time (accelerometer‐free) computed‐torque robot‐control algorithm founded upon our discrete dynamic robot model.2Numerical experiments with the cylindrical robot confirm both the robust disturbance rejection characteristics and the practical applicability of our discrete‐time computer‐tor

ISSN:0741-2223    

DOI:10.1002/rob.4620040108

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis article describes a new calibration system for robot manipulators which improves their absolute positioning accuracy by using parameter‐estimation algorithms based on the Newton method. When 3D position data of the specified points on a manipulator and the joint encoder values are input to the calibration system, the system estimates the offset values of joint encoders, link lengths, and position and orientation of the manipulator base coordinate system with respect to the world coordinate system which is difficult to obtain by conventional calibration methods. This calibration system can be applied to various manipulator types by just changing the basic kinematic equations. The system employs an algebraic programming system called REDUCE to automatically reduce the manipulator kinematic equation and partial differential calculus in the Newton method. For efficiency, first only the arm part with three degrees of freedom and then the hand part are calibrated. The experimental results demonstrate the effectiveness of this system by reducing the robot's absolute positioning errors to the order of repeatability error

ISSN:0741-2223    

DOI:10.1002/rob.4620040109

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

年代:1987

数据来源: WILEY

摘要:

AbstractA new adaptive‐control scheme for direct control of manipulator end effector to achieve trajectory tracking in Cartesian space is developed in this article. The control structure is obtained from linear multivariable theory and is composed of simple feedforward and feedback controllers and an auxiliary input. The direct adaptation laws are derived from model reference adaptive control theory and are not based on parameter estimation of the robot model. The utilization of adaptive feedforward control and the inclusion of auxiliary input are novel features of the present scheme and result in improved dynamic performance over existing adaptive control schemes. The adaptive controller does not require the complex mathematical model of the robot dynamics or any knowledge of the robot parameters or the payload, and is computationally fast for on‐line implementation with high sampling rates. The control scheme is applied to a two‐link manipulator for illustr

ISSN:0741-2223    

DOI:10.1002/rob.4620040110

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.4620040111

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

年代:1987

数据来源: WILEY