Time filter

Source Type

Wang Z.-Q.,Beijing Institution of Technology | Li L.-H.,Beijing Institution of Technology | Liu X.,Shenyang Aerospace University | Zhang Y.-S.,Beihang University
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2016

To realize the rapid alignment of the shipborne aircrafts with large initial heading error, a rotation vector error (RVE) model is deduced. The velocity matching and the velocity plus angular rate matching methods are respectively applied to implement the transfer alignment algorithm. In view of the stability and rapidity of nonlinear filter, a square-root unscented Kalman filter is used to estimate the attitude misalignment. Simulation results shows that the rotation vector error model has higher accuracy compared with the nonlinear phi angle model, and by using the velocity plus angular rate matching method, the transfer alignment of shipborne aircraft inertial navigation system can be accomplished in 50 s, and the horizontal and heading precisions are within 20″ and 1', respectively. These show that the proposed algorithm can meet the rapidity and accuracy requirements of the transfer alignment. © 2016, Editorial Department of Journal of Chinese Inertial Technology. All right reserved.

Chen J.,Beijing Institution of Technology | Zhang G.,Beijing Institution of Technology | Li Z.,Beijing Institution of Technology
International Journal of Adaptive Control and Signal Processing | Year: 2011

In this paper, we proposed an on-line parameter estimation algorithm for a class of time-varying continuous systems with bounded disturbance. In this method, a novel polynomial approximator with a bounded regressor vector is constructed and utilized to approximate the time-varying parameters. The direct least-squares algorithm is employed to acquire the on-line estimates, so that several useful properties of the direct estimation, such as fast convergence and robustness to the bounded disturbance, are reflected in our method. We have proved that the estimation error of this method is bounded. Furthermore, the bound on the Euclidean norm of the estimation error is derived. The simulation results demonstrate that this method can provide accurate estimates of time-varying parameters even under the influence of bounded disturbance. © 2010 John Wiley & Sons, Ltd.

Wang X.,Beijing Institution of Technology | Fu M.,Intelligent Systems Technology, Inc. | Yang Y.,Intelligent Systems Technology, Inc. | Ma H.,Intelligent Systems Technology, Inc.
2013 25th Chinese Control and Decision Conference, CCDC 2013 | Year: 2013

Autonomous vehicles have attracted considerable attention in the research community and industry due to their potential benefits to unmanned driving and assisted driving. This paper addresses the problem of designing lateral control law and the strategy of determining the giving speed for autonomous vehicles. An improved method of calculating lateral offset and angle error based on multiple look-ahead distances is proposed to reduce the impact of noise in reference path data on the lateral control system. Multiple fuzzy inference engines are used to design the steering controller and determine the given driving speed including forward and backward to deal with both simple and complex reference paths. Satisfactory simulation and experimental results have been obtained for different reference paths including a path with U-turn task in which backward driving is needed. © 2013 IEEE.

Wu J.-T.,Beijing Institution of Technology | Zhang J.-G.,Beijing Institution of Technology | Yin X.,Beijing Institution of Technology | Wu L.,Beijing Institution of Technology
New Journal of Chemistry | Year: 2016

Several novel nitrogen-rich salts of 3-hydrazino-4-amino-1,2,4-triazole (HATr) were synthesized by means of metathesis reactions or Brønsted acid-base reactions in this work. These nitrogen-rich salts were fully characterized by means of single-crystal X-ray diffraction, elemental analysis, and infrared. Their structures showed that the extensive hydrogen bonding interactions between the cations and anions formed a complex 3D network, which contributes to the high density of the salts. Some of these salts exhibited reasonable thermal stability (Td = 168-266 °C) and good impact sensitivities (IS = 4-40 J). In addition, the detonation pressures and velocities of the energetic salts were calculated, ranging from 23.1 GPa to 32.3 GPa and 7421 m s-1 to 8455 m s-1, respectively. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.

Yang C.,University of Plymouth | Ma H.,Beijing Institution of Technology
Proceedings of the 30th Chinese Control Conference, CCC 2011 | Year: 2011

In this paper, adaptive control aiming at asymptotic tracking is investigated for a class of NARMA (nonlinear autoregressive moving average) systems with periodic time-varying parameters, unknown time delay and nonparametric nonlinear uncertainties. A time-varying dead zone with diminishing threshold is designed in the parameter estimator to deal with both parametric and nonparametric uncertainties. The effect of the nonparametric uncertainties as well as unknown time delay has been compensated for by the developed nearest-neighbor previous instant estimation technique. The closed loop stability and asymptotic tracking performance have been rigorously established by theoretic proof. © 2011 Chinese Assoc of Automati.

Ma H.,Beijing Institution of Technology | Wang M.,Beijing Institution of Technology | Jia Z.,Beijing Institution of Technology | Yang C.,University of Plymouth
Proceedings of the 30th Chinese Control Conference, CCC 2011 | Year: 2011

In the past decade, cooperation of swarm of mobile robots has been extensively studied for its high error tolerance, efficiency, scalar extendibility and wide applications in various services and surveillances. Among most of these applications, the robots are required to formate into certain shape or positions so as to accomplish tasks with satisfied overall performance, hence multi-robot formation problem has received increasing attention in the research community and has been studied from different aspects. This contribution aims at one long-term ignored fundamental problem of describing the formation rigorously in a mathematical manner and establishing one general framework of optimal multi-robot formation problem, which can serve as a theoretical basis for later studies on robot formation. Within the proposed framework, the preliminary case studies to three-robot optimal formation problem have shown that the formulated optimal formation problems are generally non-trivial and challenging even for the most simple three-robot optimal line formation problems. © 2011 Chinese Assoc of Automati.

Ma H.,Beijing Institution of Technology | Rong L.,Beijing Institution of Technology | Wang M.,Beijing Institution of Technology | Fu M.,Beijing Institution of Technology
Proceedings of the 30th Chinese Control Conference, CCC 2011 | Year: 2011

Following our previous paper on an extremely simple yet long-term ignored one-step-guess (OSG) estimator, which focuses on the adaptive regulation problem of a class of the scalar discrete-time adaptive control system, this contribution aims at examining the counterpart tracking problem with the OSG estimator and its two variants, all of which are shown to be efficient yet rather nontrivial although the form of the OSG estimator is very simple. The OSG estimator is based on the most intuitive idea of guessing the unknown parameter with only the information available from one step, and applying it to the tracking problem with the certainty-equivalence principle results in a complex closed-loop system, which is indeed governed by a time-varying nonlinear difference equation whose stability is not resolved in previous studies of difference equations. Preliminary closed-loop stability analysis is given under wild conditions, and two variants of the OSG-based adaptive controller, called parameter regularized OSG and control regularized OSG, are also proposed to make up weakness of the primordial OSG controller. Extensive numerical simulations also illustrate the effectiveness and differences of the proposed methods. © 2011 Chinese Assoc of Automati.

Chen Z.,Beijing Institution of Technology | Leung K.,University of Hong Kong
ICIME 2010 - 2010 2nd IEEE International Conference on Information Management and Engineering | Year: 2010

Previous research indicated that task conflict benefits knowledge sharing (KS), whereas relationship conflict damages it. However, little is known about the underlying process by which the two types of conflicts affect KS. By integrating conflict theory and transactive memory system (TMS) theory, this paper presented a mediational model to test whether two types of conflict have different effects on team KS through TMS. Besides, this study also examined whether task type moderates the proposed mediational processes. Results of a study of 386 employees in 76 teams show that task conflict has positive effects on team KS through TMS. More interestingly, it is found that the task conflict-TMS-KS sequence only significant when task type is nonroutine rather than it is routine. Relationship conflict has a negative effect on team KS through TMS. Theoretical and practical implications of these findings are discussed. © 2010 IEEE.

PubMed | Beijing Institution of Technology
Type: Journal Article | Journal: Chemistry, an Asian journal | Year: 2016

Metallic germanium is an ideal anode for lithium-ion batteries (LIBs), owing to its high theoretical capacity (1624mAhg(-1) ) and low operating voltage. Herein, we highlight recent advances in the development of Ge-based anodes in LIBs, although improvements in their coulombic efficiency (CE), capacity retention, and rate performance are still required. One of the major concerns facing the development of Ge anodes is the controlled formation of microstructures. In this Focus Review, we summarize Ge-based materials with different structural dimensions, that is, zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), three-dimensional (3D), and even monolithic and macroscale structures. Moreover, the design of Ge-based oxide materials, as an effective route for achieving higher Li-storage capacities and cycling performance, is also discussed. Finally, we briefly summarize new types of Ge-based materials, such as ternary germanium oxides, germanium sulfides, and germanium phosphides, and predict that they will bring about a reformation in the field of LIBs.

PubMed | Beijing Institution of Technology
Type: Journal Article | Journal: Chemistry, an Asian journal | Year: 2015

Energetic mono- and dicationic 3,4-diaminotriazolium salts have been prepared by combining stoichiometric amounts (1:1 or 2:1 molar ratio) of 3,4-diaminotriazole with various oxygen-containing tetrazoles, and the structures have been confirmed by single-crystal XRD for the first time. All structures are dominated by a strong hydrogen-bond network owing to both amino groups and oxygen in the molecule. All salts, except 7, exhibit excellent thermal stabilities with decomposition temperatures over 200C. Based on experimental densities and theoretical calculations carried out by using the Gaussian03 suite of programs, all salts have calculated detonation pressures (20.3-33.9GPa) and velocities (7095-8642ms(-1)).

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