5,666 research outputs found

    Redundancy of space manipulator on free-flying vehicle and its nonholonomic path planning

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    The nonholonomic mechanical structure of space robots and path planning is discussed. The angular momentum conservation works as a nonholonomic constraint while the linear momentum conservation is a holonomic one. Thus, a vehicle with a 6 d.o.f. manipulator is described as a 9 variable system with 6 inputs. This implies the possibility of controlling the vehicle orientation and the joint variables of the manipulator by actuating the joint variables, but only if the trajectory is carefully planned; however, both of them cannot be controlled independently. It means that by assuming feasible-path planning, a system that consists of a vehicle and a 6 d.o.f. manipulator can be utilized as 9 d.o.f. system. Initially, the nonholonomic mechanical structure of space vehicle/manipulator system is shown. Then a path planning scheme for nonholonomic systems is proposed using Lyapunov functions

    Morphological Network: How Far Can We Go with Morphological Neurons?

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    In recent years, the idea of using morphological operations as networks has received much attention. Mathematical morphology provides very efficient and useful image processing and image analysis tools based on basic operators like dilation and erosion, defined in terms of kernels. Many other morphological operations are built up using the dilation and erosion operations. Although the learning of structuring elements such as dilation or erosion using the backpropagation algorithm is not new, the order and the way these morphological operations are used is not standard. In this paper, we have theoretically analyzed the use of morphological operations for processing 1D feature vectors and shown that this gets extended to the 2D case in a simple manner. Our theoretical results show that a morphological block represents a sum of hinge functions. Hinge functions are used in many places for classification and regression tasks (Breiman (1993)). We have also proved a universal approximation theorem -- a stack of two morphological blocks can approximate any continuous function over arbitrary compact sets. To experimentally validate the efficacy of this network in real-life applications, we have evaluated its performance on satellite image classification datasets since morphological operations are very sensitive to geometrical shapes and structures. We have also shown results on a few tasks like segmentation of blood vessels from fundus images, segmentation of lungs from chest x-ray and image dehazing. The results are encouraging and further establishes the potential of morphological networks.Comment: 35 pages, 19 figures, 7 table

    Shared-Sensing and Control Using Reversible Transducers

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    As an alternative to self-sensing, we propose the concept of shared-sensing for reversible transducers. In shared-sensing, reversible transducers are continuously switched between actuator and sensor modes. This results in a hybrid system, and, in this paper, we investigate stability properties of the equilibrium for linear systems and a class of nonlinear systems with a single shared-sensing transducer. Our theoretical results are validated through simulations and experiments with a dc servo motor

    The correct structures of the ortho-cyclized products in the cycloalkylations of 1-m-methoxybenzyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one and 1-m-methoxybenzyl-octalins: X-ray structure determination of (±)-4-methoxy-9a-carbamorphinan-16-one

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    The previously assigned (ref.1) ortho-cycloalkylated product from the reaction of 1 and 2 respectively, with ortho-phosphosphoric acid and polyphosphoric acid, has been corrected to (±)-4-methoxy-9a-carbamorphinan-16-one (6) and the respective ether 7 by a single crystal X-ray structure determination of 6

    Entrapment and catalytic activity of gold nanoparticles in amine-functionalized MCM-41 matrices synthesized by spontaneous reduction of aqueous chloroaurate ions

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    There is tremendous current interest in the generation of nano-hybrid materials using silicate mesoporous materials. We describe herein a new process for the synthesis of gold nanoparticle-amine functionalized MCM-41 hybrid materials by the spontaneous reduction of chloroaurate ions within the silicate matrix. The gold nanoparticles thus formed are bound to the pores of the MCM-41 framework by amine functional groups and show excellent catalytic activity in hydrogenation reactions
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