By maximizing manipulability, the coordination of multi-arm can be enhanced. In this paper, a method to optimize the manipulability index of cooperative manipulation for a free-floating multi-arm space robot is propos...
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By maximizing manipulability, the coordination of multi-arm can be enhanced. In this paper, a method to optimize the manipulability index of cooperative manipulation for a free-floating multi-arm space robot is proposed. Firstly, the manipulability optimization is formulated as a nonlinear optimize problem at position level which is hard to solve online. By redefining constraint equation and manipulability index, it is transformed to a constrained quadratic program problem at velocity level incorporating joint velocity physical limits, which generates joint velocity commands to control the multi-arm to complete predefined tasks. Owing to dynamic coupling effects and closed chain constraints formed by cooperative manipulation, the manipulability index is more complex than that of fixed-base or mobile-base manipulators. Hence, the gradient of the index is approximated by numerical algorithms. Simulations based on a dual-arm space robot model are conducted and the results prove that the proposed method is efficient to optimize the manipulability index. Copyright (C) 2020 The Authors.
A three-dimensional model of the thorax is developed from serial cross-sectional images of the human body which were obtained via X-ray computerized tomography scans. The procedures involved in the high-resolution geo...
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ISBN:
(纸本)0879425598
A three-dimensional model of the thorax is developed from serial cross-sectional images of the human body which were obtained via X-ray computerized tomography scans. The procedures involved in the high-resolution geometrical modeling and electromagnetic computational analysis are described. It is shown that this methodology can readily be applied to the forward and inverse problems of electrocardiography. The results of some forward simulation are shown as isopotential and isofield maps.
The process of satisfying daily demands is a fundamental aspect of humans' daily lives. With the advancement of embodied AI, robots are increasingly capable of satisfying human demands. Demand-driven navigation (D...
ISBN:
(纸本)9798331314385
The process of satisfying daily demands is a fundamental aspect of humans' daily lives. With the advancement of embodied AI, robots are increasingly capable of satisfying human demands. Demand-driven navigation (DDN) is a task in which an agent must locate an object to satisfy a specified demand instruction, such as "I am thirsty." The previous study typically assumes that each demand instruction requires only one object to be fulfilled and does not consider individual preferences. However, the realistic human demand may involve multiple objects. In this paper, we introduce the Multi-object Demand-driven Navigation (MO-DDN) benchmark, which addresses these nuanced aspects, including multi-object search and personal preferences, thus making the MO-DDN task more reflective of reallife scenarios compared to DDN. Building upon previous work, we employ the concept of "attribute" to tackle this new task. However, instead of solely relying on attribute features in an end-to-end manner like DDN, we propose a modular method that involves constructing a coarse-to-fine attribute-based exploration agent (C2FAgent). Our experimental results illustrate that this coarse-to-fine exploration strategy capitalizes on the advantages of attributes at various decision-making levels, resulting in superior performance compared to baseline methods. Code and video can be found at https://***/view/moddn.
Background and present status of urban transportation planning process is described;critique of present state of methodology is discussed in context of systems approach;some unique problems and issues of transportatio...
Background and present status of urban transportation planning process is described;critique of present state of methodology is discussed in context of systems approach;some unique problems and issues of transportation systems planning are pointed out, and needed directions of future development are indicated.
We describe three dimensional chemical mapping of a 2x10x10 micron volume of a toner particle by scanning transmission X-ray microscopy using serial section sampling and computer reconstruction. To our knowledge this ...
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We describe three dimensional chemical mapping of a 2x10x10 micron volume of a toner particle by scanning transmission X-ray microscopy using serial section sampling and computer reconstruction. To our knowledge this is the first example of serial section 3d imaging by soft X-ray microscopy. This is an attractive alternative to tomography when sample density is large and detailed 3-d chemical information requires image acquisition at a number of X-ray energies.
The optimal directed acyclic graph search problem constitutes searching for a DAG with a minimum score, where the score of a DAG is defined on its structure. This problem is known to be NP-hard, and the state-of-the-a...
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ISBN:
(纸本)9783319495835;9783319495828
The optimal directed acyclic graph search problem constitutes searching for a DAG with a minimum score, where the score of a DAG is defined on its structure. This problem is known to be NP-hard, and the state-of-the-art algorithm requires exponential time and space. It is thus not feasible to solve large instances using a single processor. Some parallel algorithms have therefore been developed to solve larger instances. A recently proposed parallel algorithm can solve an instance of 33 vertices, and this is the largest solved size reported thus far. In the study presented in this paper, we developed a novel parallel algorithm designed specifically to operate on a parallel computer with a torus network. Our algorithm crucially exploits the torus network structure, thereby obtaining good scalability. Through computational experiments, we confirmed that a run of our proposed method using up to 20,736 cores showed a parallelization efficiency of 0.94 as compared to a 1296-core run. Finally, we successfully computed an optimal DAG structure for an instance of 36 vertices, which is the largest solved size reported in the literature.
The differential detection of an MFSK signal, which uses multiple symbols as interval of observation, is analysed. A recursive differential detection algorithm, simplified and with a comparable error rate, is proposed...
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The differential detection of an MFSK signal, which uses multiple symbols as interval of observation, is analysed. A recursive differential detection algorithm, simplified and with a comparable error rate, is proposed and its performance analysed. This algorithm is considered in the instance of a mobile radio link between a base station and a mobile station, for which a means of Doppler effect detection and correction is proposed.< >
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