This paper presents a control design based on the method of virtual constraints and hybrid zero dynamics to achieve stable running on MABEL, a planar biped with compliance. In particular, a time-invariant feedback con...
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This paper presents a control design based on the method of virtual constraints and hybrid zero dynamics to achieve stable running on MABEL, a planar biped with compliance. In particular, a time-invariant feedback controller is designed such that the closed-loop system not only respects the natural compliance of the open-loop system, but also enables active force control within the compliant hybrid zero dynamics and results in exponentially stable running gaits. The compliant-hybrid-zero-dynamics-based controller with active force control is implemented experimentally and shown to realize stable running gaits on MABEL at an average speed of 1.95 m/s (4.4 mph) and a peak speed of 3.06 m/s (6.8 mph). The obtained gait has flight phases upto 39% of the gait, and an estimated ground clearance of 7.5 - 10 cm.
In this paper the problem of robust coordination of multi-agent systems via energy-shaping is studied. The agents are nonidentical, Euler-Lagrange systems with uncertain parameters. The control objective is to drive a...
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In this work, we propose a recursive local linear estimator (RLLE) for identification of nonlinear autoregressive systems with exogenous inputs, along with an analysis of its strong consistency and asymptotical mean s...
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This paper proposes a maximum power point tracking scheme using neural networks for a grid connected photovoltaic system. The system is composed of a photovoltaic array, a boost converter, a three phase inverter and g...
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This paper proposes a maximum power point tracking scheme using neural networks for a grid connected photovoltaic system. The system is composed of a photovoltaic array, a boost converter, a three phase inverter and grid. The neural network proposed can predict the required terminal voltage of the array in order to obtain maximum power. The duty cycle is calculated and the boost converter switches are controlled. Hysteresis current technique is applied on the three phase inverter so that the output voltage of the converter remains constant at any required set point. The complete system is simulated using MATLAB/SIMULINK software under sudden weather conditions changes. Results show accurate and fast response of the converter and inverter control and which leads to fast maximum power point tracking.
Based on the principle that the selection of delay time and embedding dimension has no correlation in the process of phase space reconstruction, this paper puts forward a new method of identifying the embedding dimens...
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Based on the principle that the selection of delay time and embedding dimension has no correlation in the process of phase space reconstruction, this paper puts forward a new method of identifying the embedding dimension by Cao Liangyue Theory (CAO Theory) after the delay time is identified by Mutual Information Function. By means of the numerical verification of a few typical examples of chaotic dynamic system, the result shows that the method can identify the valid delay time of phase space reconstruction and the best embedding dimension. In addition, a new way of identifying the chaotic signal is provided and this method can effectively reconstruct the phase space of the original system from the time series.
This paper presents an adaptive controller for the bilateral teleoperation of a system composed by a single local manipulator and multiple cooperative remote manipulators handling a common object. First, the nonlinear...
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This paper presents an adaptive controller for the bilateral teleoperation of a system composed by a single local manipulator and multiple cooperative remote manipulators handling a common object. First, the nonlinear operational space dynamical behavior of the complete teleoperation system is derived. Then, under the assumptions that the remote manipulators are rigidly grasping a non-deformable object and that the communications may induce constant time-delays, it is proved that velocities and position-orientation error between the local manipulator end-effector and the object asymptotically converge to zero. Simulations results are included to show the effectiveness of the proposed approach.
Because of the forward and reverse operations in green e-commerce, its trust management forms a closed-loop structure. Based on its closed-loop network model, a novel trust chain management model and corresponding eva...
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ISBN:
(纸本)9781467344975
Because of the forward and reverse operations in green e-commerce, its trust management forms a closed-loop structure. Based on its closed-loop network model, a novel trust chain management model and corresponding evaluation system are established. Further, trust value measurement in green e-commerce is described as a fuzzy multi- objective group decision making (FMOGDM) problem with uncertain group preference, solved by a fuzzy TOPSIS and illustrated by a numerical example.
Mashhad, the second largest city in Iran, like many other big cities, is faced with increasing traffic congestion owing to rapidly increasing population and annual pilgrimage. In recent years, Mashhad traffic and tran...
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Mashhad, the second largest city in Iran, like many other big cities, is faced with increasing traffic congestion owing to rapidly increasing population and annual pilgrimage. In recent years, Mashhad traffic and transportation authorities have been challenged with how to manage the increasing congestion with limited budgets for major roadway construction projects. Mashhad has recognized the need to improve the existing system capacity to get the most out of their cur- rent transportation system infrastructures. Since most of the delay times occur at signalized intersections, using an intelligent control system with proper capabilities to overcome the growing traffic requirements is recommended. Following comprehensive studies carried out with the aim of developing the Mashhad traffic control center, the SCATS adaptive traffic control system was introduced as the selected intelligent control system for integrating signalized intersections. The first intersection was equipped with this system in 2005. This paper describes the results of a field evaluation in which fixed actuated-coordinated signal timings are compared with those dynamically computed by SCATS. The ef- fects of this system on optimizing fuel consumption as well as reducing air pollutants are fully discussed. It is found that SCATS consistently reduced travel times and the average delay per stopped or approaching vehicle. The positive impact of adaptive traffic control systems on fuel consumption and air pollution are also highlighted.
We are developing the Trans-PET BioCaliburn, an all-digital positron emission tomography (PET) scanner designed for state-of-the-art molecular imaging of animals at Huazhong University of science and Technology (HUST)...
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We are developing the Trans-PET BioCaliburn, an all-digital positron emission tomography (PET) scanner designed for state-of-the-art molecular imaging of animals at Huazhong University of science and Technology (HUST). The basic detector module (BDM) receives annihilation photons, generates scintillation pulses, which are digitized by use of the multi-voltage threshold (MVT) sampling method previously developed and reported by us, and sends single events' time, energy, and position to a personal computer. In the personal computer, post acquisition energy calibration, crystal identification, and coincidence detection are performed. It can arrange the BDMs into various scanner geometries for different imaging needs. In this work, we describe the design and implementation of a hexagonal ring PET scanner with six BDMs, for small animal imaging studies. The scanner, Trans-PET BioCaliburn SH1.0 has a transaxial field-of-view (FOV) of 9.2 cm diameter and axial FOV of 5.3 cm. The typical energy resolution is 14.2% full-width-at-half-maximum (FWHM) at 511 keV, and the coincidence timing resolution is 1.4 ns FWHM. Phantom images show that our small animal PET scanner can resolve 1.2 mm diameter rods that are separated by 2.0 mm. We also demonstrate the imaging capabilities of the scanner with in vivo images of mice.
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