作者:
Chen JieKai ShixiongSchool of Automation
Beijing Institute of Technology Key Laboratory of Intelligent Control and Decision of Complex SystemsMOE Beijing 100081
This paper investigates the problem of distributed control of multiple redundant mobile manipulators to collectively transport an object tracking a desired trajectory with energy and manipulability optimized. To solve...
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This paper investigates the problem of distributed control of multiple redundant mobile manipulators to collectively transport an object tracking a desired trajectory with energy and manipulability optimized. To solve this optimization problem, formation control tasks are introduced as equality constraints with the variables being the velocities. In this paper, we propose a distributed proximal gradient algorithm searching for the optimal solution, with which the stability of the closed-loop system is proved. Simulations demonstrate the effectiveness of the proposed distributed optimization scheme and proximal algorithm.
The current state, characteristics and necessity of the low voltage ride through (LVRT) on-site testing for grid-connected offshore wind turbines are introduced firstly. Then the effects of submarine cables on the LVR...
The current state, characteristics and necessity of the low voltage ride through (LVRT) on-site testing for grid-connected offshore wind turbines are introduced firstly. Then the effects of submarine cables on the LVRT testing are analysed based on the equivalent circuit of the testing system. A scheme for eliminating the effects of cables on the proposed LVRT testing method is presented. The specified voltage dips are guaranteed to be in compliance with the testing standards by adjusting the ratio between the current limiting impedance and short circuit impedance according to the steady voltage relationship derived from the equivalent circuit. Finally, simulation results demonstrate that the voltage dips at the high voltage side of wind turbine transformer satisfy the requirements of testing standards.
In this paper, an improved adaptive time-varying sliding mode controller (SMC) is designed for five-phase dual-rotor permanent magnet synchronous motor (FDRPMSM). It focuses on three objectives: 1) maintaining the hig...
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This paper is concerned with the semi-global output synchronization problem of a heterogeneous network under self-triggered control. A distributed self-triggered control scheme in which only local information is used ...
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This paper is concerned with the semi-global output synchronization problem of a heterogeneous network under self-triggered control. A distributed self-triggered control scheme in which only local information is used to compute the triggering instants is proposed. In addition, the Zeno behavior can be excluded in the designed scheme. By adopting the low-gain technique, it is shown that the input saturation nonlinearity can be avoided if the parameter of the parameterized feedback gain is chosen small enough. The algorithm for implementing the self-triggered rule is also presented in the paper.
In order to compensate for the impact of time delay on the estimation of object feature point image and image Jacobian matrix and improve the control precision of image-based visual servo system, a Kalman filtering al...
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In order to compensate for the impact of time delay on the estimation of object feature point image and image Jacobian matrix and improve the control precision of image-based visual servo system, a Kalman filtering algorithm with colored noise is proposed to obtained the current motion state estimation of the feature point with time-delay compensation in the image space, then the accurate image Jacobian matrix under time delay can be obtained. For the above, the following work will be done in this paper: (1) the current motion state estimation of the feature point in the image space is predicted by Kalman filtering algorithm, combined with practical applications, measurement noise is usually as colored noise and can be regarded as a one-order Markov sequence excited by Gauss white noise, then a Kalman filtering recursive model can be derived according to the variance minimization principle of the estimation error;(2) to obtain the measurement vectors estimation which cannot be acquired in the Kalman filtering model owing to the existence of time delay, the relationship between the motion state of the feature point at the prior and later point is established, and a polynomial is fitted by using some of the observed data under the relationship to realize the measurement vectors estimation in the time-delay period. Thus the estimation of the motion state of the feature point at the current time in the image space can be obtained, and the estimation of image Jacobian matrix with time-delay compensation can be obtained. Experimental results validate the feasibility and superiority of this method.
Stability of a networked predictive controlsystem subject to network-induced delay and data dropout is investigated in this study. By modeling the closed-loop system as a switched system with an upper-triangular stru...
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Stability of a networked predictive controlsystem subject to network-induced delay and data dropout is investigated in this study. By modeling the closed-loop system as a switched system with an upper-triangular structure, a necessary and sufficient stability criterion is developed. From the criterion, it also can be seen that separation principle holds for networked predictive controlsystems. A numerical example is provided to confirm the validity and effectiveness of the obtained results.
Organic-inorganic hybridized perovskites have attracted more and more attention due to their advantages such as high absorption coefficients, direct band-gap, long carrier lifetimes, balanced electron/hole mobility, *...
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Organic-inorganic hybridized perovskites have attracted more and more attention due to their advantages such as high absorption coefficients, direct band-gap, long carrier lifetimes, balanced electron/hole mobility, ***-scaled perovskites, which possess naturally-formed optical feedback, can excite resonance under certain incident light and realize the precise light management as *** 2014, Ha et *** lead halide perovskite nanoplatelets with regular triangular or hexagonal morphologies by vapor phase deposition techniques on mica plate [1].Later, they realized lasing based on the whispering-gallery modes at the near-infrared range using the prepared perovskite nanoplatelets [2].Here, we first synthesized lead iodide nanoplatelets with well-defined crystal boundaries and then successfully conversed the pre-grown lead iodide template into perovskite nanoplatelets by placing the substrate exactly above the methyl iodide amine powder in Ar gas condition with all valves of the quartz tube *** a continuous-wave laser at 325 nm, we measured the photoluminescence spectra of different perovskite nanoplatelets and observed the whispering gallery modes over the spontaneous emission band.
With the development of artificial intelligence technology, robotics technology has become more and more mature. Ground walking robots not only develop rapidly, but also have been applied in actual production and life...
With the development of artificial intelligence technology, robotics technology has become more and more mature. Ground walking robots not only develop rapidly, but also have been applied in actual production and life. However, the development of wall climbing robot technology is still in the laboratory research and small-scale application. We live in a world where progress is continuing. Large-scale buildings, bridges and ships are becoming more and more common. In these places, it is inevitable to involve the construction, maintenance and clarity of high-rise buildings and ships. In the case of dangerous and inefficient manpower work, the application of wall climbing robots can play a very good role. Therefore, the development of wall climbing robots is of vital importance both now and in the future. Starting from the performance characteristics of wall climbing robot, this paper studies and summarizes the moving mode, control mode, conditions to be satisfied and various adsorption forms of wall climbing robot, and introduces the basic research situation in the field of wall climbing robot.
In networked load frequency control (LFC) systems, time-varying delays could come from two aspects: measurements' transmission from power plant to control center and control signals from the control center to plan...
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In networked load frequency control (LFC) systems, time-varying delays could come from two aspects: measurements' transmission from power plant to control center and control signals from the control center to plant side, because of the use of open communication networks. Those delays can affect the dynamic performance and the stability of the system. In this paper, the two delays are considered in one-area LFC system, instead of combining these two delays into one, when the delay-dependent stability analysis is carried out by using Lyaponuvtheory and linear matrix inequality (LMI) technique. Moreover, the dynamic delay interval method is employed to derive less conservative delay-dependent stability criteria for such time-delay system compared with the existing results. Finally, the effectiveness of the proposed criteria are verified by two case studies.
A soft-switching solution implemented to the traditional bidirectional DC/DC converter is developed. The soft-switching cell, which composed of three auxiliary switches, one resonant capacitor and one resonant inducto...
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A soft-switching solution implemented to the traditional bidirectional DC/DC converter is developed. The soft-switching cell, which composed of three auxiliary switches, one resonant capacitor and one resonant inductor, is equipped in the traditional bidirectional DC/DC converter to realize circuit ZCT or ZVT operations in both energy transmission directions. Two driving methods are presented to charging energy for different storage applications according to the storage materials' electrical characteristics. There are two methods in buck mode. The first method with low conduction losses suffers from a hard turning off process in one of the auxiliary switches, while the others experience the soft operation. As for the other method, the zero voltage or zero current transmissions in all switches are realized, however, the relative higher but fixed conduction losses are introduced by the resonant circle. And the proposed topology of bidirectional soft-switching dc-dc converter (TASBC) performs ideal soft switching at boost operations. The characteristics of the proposed converter has been verified by MATLAB simulations and experimental results.
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