In this paper, an adaptive fuzzy scheme for trajectory tracking is developed for robotic systems with parameter uncertainties and external disturbance. Within the scheme, a fuzzy logic system is employed to approximat...
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In this paper, an adaptive fuzzy scheme for trajectory tracking is developed for robotic systems with parameter uncertainties and external disturbance. Within the scheme, a fuzzy logic system is employed to approximate the unknown robotic dynamics. Then, an adaptive fuzzy controller is obtained which combine with the adaptive methods so as to eliminate the system uncertainties and external disturbance. And the adaptive laws are obtained through stable control algorithms based on the Lyapunov stability theorem. Moreover, extra control terms are designed to cancel the approximation errors, and the adjustable gains obtained from a Fuzzy Logic System (FLS) are considered to receive the satisfying control effects. The proposed controller is robust to structured uncertainties and unstructured uncertainties, and the validity of the control scheme is shown by simulations on a novel 2-DOF parallel mechanism, which is driven by linear motors.
There are some fatigue damage estimation methods for an austenitic stainless steel that uses martensitic transformation. For instance, those are the remanent magnetization method, the excitation method using the diffe...
There are some fatigue damage estimation methods for an austenitic stainless steel that uses martensitic transformation. For instance, those are the remanent magnetization method, the excitation method using the differential pick‐up coil, and so on. We are researching also those two methods in our laboratory now. In the remanent magnetization method, it is well known that the relationship between fatigue damage and the remanent magnetization is simple, clear, and reproducible. In addition, the excitation method can be easily used at the job site because the special magnetizer is unnecessary. But, these methods have some disadvantages shown as follows. For instance, the former needs a special magnetizer and the latter’s output signal is small. On the other hand, it is well known that the inductance of a pancake type coil put on the metallic specimen changes according to the electromagnetic properties of the metallic specimen. In this paper, the assessment method of fatigue of an austenitic stainless steel (SUS316) that uses the change by fatigue of the inductance of the pancake type coil measured with the LCR meter is shown. In addition, the fatigue evaluation performance of this method is described.
作者：
K. CaiW. M. WonhamaSystems Control Group
Department of Electrical and Computer Engineering University of Toronto 10 King’s College Road Toronto ON M5S 3G4 Canada
A purely distributed control paradigm is proposed for discrete‐event systems (DES). In contrast to control by one or more external supervisors, distributed control aims to design built‐in strategies for individual a...
A purely distributed control paradigm is proposed for discrete‐event systems (DES). In contrast to control by one or more external supervisors, distributed control aims to design built‐in strategies for individual agents. First a distributed optimal nonblocking control problem is formulated. To solve it, a top‐down localization procedure is developed which systematically decomposes an external supervisor into local controllers while preserving optimality and nonblockingness. An efficient localization algorithm is provided to carry out the computation, and an automated guided vehicles (AGV) example presented for illustration. Finally, the ‘easiest’ and ‘hardest’ boundary cases of localization are discussed.
A novel finite word length(FWL) controller design is developed in the framework of mixed μ theory.A robust FWL controller performance measure is proposed which takes into account the standard robust control requireme...
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A novel finite word length(FWL) controller design is developed in the framework of mixed μ theory.A robust FWL controller performance measure is proposed which takes into account the standard robust control requirements as well as the FWL implementation considerations, and the corresponding FWL robust controller design problem is naturally reformulated as a mixed μ problem which can be treated effectively with the results of mixed μ theory.
This paper introduces two concepts of the traditional quality evaluation: the subjective evolution and objective evaluation, and then several kinds of common used human visual perception image quality judgment criteri...
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This paper introduces two concepts of the traditional quality evaluation: the subjective evolution and objective evaluation, and then several kinds of common used human visual perception image quality judgment criterion are introduced, such as: assessing the quality of enhanced images based on human visual perception, image quality assessing model by using neural network and support vector machine, gradient information based image quality assessment, natural image quality assessment metric based on wavelet-based contour-let transform, image quality assessment method based on contrast sensitivity. Some possible development directions are given for the image quality assessment research.
Combining the human visual system with the image local properties, this paper proposes a novel watermarking algorithm based on ridgelet transform and fuzzy c-means (FCM) clustering. In order to obtain a sparse represe...
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Combining the human visual system with the image local properties, this paper proposes a novel watermarking algorithm based on ridgelet transform and fuzzy c-means (FCM) clustering. In order to obtain a sparse representation of the image, especially for straight edge singularity, the image is first partitioned into small pieces and the ridgelet transform is applied for each piece. The image pieces are adaptively classified into frat regions and texture regions by applying FCM clustering algorithm through analyzing texture distribution in ridgelet coefficients of each piece. And the watermarking is embedded into the middle ridgelet subband in the highest energy directions of texture pieces, where the embedding strength is also adjusted by the analysis of ridgelet coefficients of each piece based on the feature of luminance masking and texture masking. Then the embedded watermark can be blindly detected by correlation detector. Experimental results prove robustness and transparency of the proposed watermarking scheme.
The modernization of the US electric power infrastructure, especially in lieu of its aging, overstressed networks; shifts in social, energy and environmental policies, and also new vulnerabilities, is a national conce...
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The modernization of the US electric power infrastructure, especially in lieu of its aging, overstressed networks; shifts in social, energy and environmental policies, and also new vulnerabilities, is a national concern. Our system are required to be more adaptive and secure more than every before. Consumers are also demanding increased power quality and reliability of supply and delivery. As such, power industries, government and national laboratories and consortia have developed increased interest in what is now called the smart grid of the future. The paper outlines smart grid intelligent functions that advance interactions of agents such as telecommunication, control, and optimization to achieve adaptability, self-healing, efficiency and reliability of power systems. The author also presents a special case for the development of dynamic stochastic optimal power flow (DSOPF) technology as a tool needed in smart grid design. The integration of DSOPF to achieve the design goals with advanced DMS capabilities are discussed herein. This reference paper also outlines research focus for developing next generation of advance tools for efficient and flexible power systems operation and control.
A variety of problems arising in communication networks, computer networks, automated manufacturing plants, etc. can be described by min-max-plus system models. Output feedback stabilization for the nonlinear, non-aut...
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Distributed Power System (DPS) have many loads with varied functions. In particular, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, a conver...
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Distributed Power System (DPS) have many loads with varied functions. In particular, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, a converter with spilt capacitors and an adaptive controller is proposed as a Voltage Bus Conditioner (VBC) to mitigate the voltage transients on the bus. The proposed converter allows the smaller capacitive storage. In addition, the proposed control approach has the advantage of requiring only one sensor and performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. Simulation results by Saber package are presented which verify the control principles and demonstrate the practicality of the approach.
Comparing with the common operating system, the secure operating system can provide the user with a more safe and reliable operating platform of the computer system. The testing to the security functions of the secure...
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Comparing with the common operating system, the secure operating system can provide the user with a more safe and reliable operating platform of the computer system. The testing to the security functions of the secure operating system has become the important measure to verify its security. On the basis of the standard on the evaluation of the security of the information technology made by China (GB/T18336-2001), this paper presents the evaluating system to the secure operating system. The evaluating system uses the keyword-driven mechanism and realizes the better automatic testing and evaluating of the operating system.
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