Quasistatic mechanical systems, in which mass or acceleration is sufficiently small for the inertial term ma in F=ma to be negligible compared to dissipative forces, are discussed. It is pointed out that many instance...
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Quasistatic mechanical systems, in which mass or acceleration is sufficiently small for the inertial term ma in F=ma to be negligible compared to dissipative forces, are discussed. It is pointed out that many instances of robotic manipulation can be well approximated as quasistatic systems, with the dissipative force being dry friction. Energetic formulations of Newton's laws have often been found useful in the solution of mechanics problems involving multiple constraints. An intuitive minimum power principle is outlined which states that a system chooses at every instant the lowest-energy, or 'easiest', motion in conformity with the constraints. Surprisingly, the principle is in general false; but it is proved that the principle is correct in the useful special case that Coulomb friction is the only dissipative or velocity-dependent force acting in the system.< >
The Laplacian of Gaussian (LoG) operator is one of the most popular operators used in edge detection. This operator, however, has some problems: zero-crossings do not always correspond to edges, and edges with an asym...
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The Laplacian of Gaussian (LoG) operator is one of the most popular operators used in edge detection. This operator, however, has some problems: zero-crossings do not always correspond to edges, and edges with an asymmetric profile introduce a symmetric bias between edge and zero-crossing locations. The authors offer solutions to these two problems. First, for one-dimensional signals, such as slices from images, they propose a simple test to detect true edges, and, for the problem of bias, they propose different techniques: the first one combines the results of the convolution of two LoG operators of different deviations, whereas the others sample the convolution with a single LoG filter at two points besides the zero-crossing. In addition to localization, these methods allow them to further characterize the shape of the edge. The authors present an implementation of these techniques for edges in 2-D images.< >
A decentralized adaptive control is proposed to stabilize and track the nonlinear interconnected subsystems with unknown parameters. The adaptation of the controller gain is derived by using model reference adaptive c...
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A decentralized adaptive control is proposed to stabilize and track the nonlinear interconnected subsystems with unknown parameters. The adaptation of the controller gain is derived by using model reference adaptive control theory based on Lyapunov's direct method. The adaptive gains consist of sigma , proportional, and integral combination of the measured and reference values of the corresponding subsystem. The proposed control is applied to the joint control of a two-link robot manipulator, and the performance in computer simulation corresponds with what is expected in theoretical development.< >
In Fourier optics, the Fourier transformation is performed on the amplitude of the electromagnetic wave, whereas in the computational method the transformation is usually applied to the grayness of its image which is ...
In Fourier optics, the Fourier transformation is performed on the amplitude of the electromagnetic wave, whereas in the computational method the transformation is usually applied to the grayness of its image which is proportional to the intensity of the electromagnetic signal.
The robotic manipulator control performance database has been expanded by experimental evaluation of a joint space model-reference adaptive control technique. The trajectory tracking accuracy of the evaluated Model-Re...
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The robotic manipulator control performance database has been expanded by experimental evaluation of a joint space model-reference adaptive control technique. The trajectory tracking accuracy of the evaluated Model-Reference Adaptive Control technique was insufficient for gross motion control of a six degree of freedom PUMA manipulator. The adaption mechanism did not force the manipulator joints to track the reference model output. The Model-Referenced Adaptive Controller demonstrated efficacy inferior to dynamics based control techniques. Velocity reference input and friction compensation have been identified as essential components of any adaptive PUMA controller. Evaluation results provide valuable insight into further development of adaptive manipulator control methods.
Vertical integration of transformation of abstract assembly task descriptions into task execution commands is needed to overcome the fundamental factors which limit the widespread application of current robotic system...
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Vertical integration of transformation of abstract assembly task descriptions into task execution commands is needed to overcome the fundamental factors which limit the widespread application of current robotic systems. These factors are the requirements for precise control of the robot task environment, custom-designed fixtures and end-effectors, and on-site robot control programming. These requirements arise because current robotic systems do not have an understanding of the robot cell environment. Further, these systems are not able to react rationally to non-deterministic events which occur during task execution. A research plan which is aimed at the systematic incorporation of limited amounts of machine intelligence into robot task planning and execution is outlined.
The problem of designing intelligent machines operating in uncertain environments with minimum supervision or interaction with a human operator is examined. The structure of an intelligent machine is defined to De the...
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The problem of designing intelligent machines operating in uncertain environments with minimum supervision or interaction with a human operator is examined. The structure of an intelligent machine is defined to De the structure of a Hierarchically Intelligent Control System, composed of three levels hierarchically ordered according to the principle of "increasing intelligence with decreasing precision," namely: the organization, the coordination and the hardware control levels. The behavior of such a machine may be managed by controls with special considerations and its "intelligence" is directly related to the derivation or a compatible measure that associates the intelligence of the higher levels with the precision of execution of the lower levels. It is shown that the concept of entropy as defined in Information Theory and Theoretical Thermodynamics is a sufficient analytic measure that unifies the treatment of all the levels of an intelligent machine as the mathematical problem of finding the right sequence of internal decisions and controls for a system structured in the order of intelligence and inverse order of precision (constraint) such that it minimizes its total entropy
Fundamental factors limiting the widespread application of current robotic systems are the requirements for precise control of the robot task environment, custom-designed fixtures and end-effectors, and on-site contro...
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Fundamental factors limiting the widespread application of current robotic systems are the requirements for precise control of the robot task environment, custom-designed fixtures and end-effectors, and on-site control program development. These requirements arise because current robotic systems do not have an understanding of the robot task environment. Further, these systems are not able to react intelligently to non-deterministic events which occur during task execution. This paper examines the nature of understanding and its use to resolve uncertainty as it relates to robot task execution. Then a research plan which is aimed at the systematic incorporation of understanding into the robot task environment is outlined.
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