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Yang C.,Zhejiang University | Mu Y.,Beijing Institute of Nearspace Vehicles System Engineering | You Z.,Tsinghua University
Advanced Materials Research | Year: 2011

The stiffness of cable flight control systems is one of the most important design parameter for aviation aircraft, because it can change the characteristic of control stick and influence the maneuverability and stability of the flight control system. Flexible cable control system is the main type of mechanical flight control system, in which movement can only be transmitted by cable in tension, the stiffness of cable control system is affected mainly by predetermined preload(PP), however the excessive PP would increase friction between cable and pulley which leads pilot an unfavorable maneuver. In this paper, the theoretical stiffness calculation of cable control system with the complex cable braided construction has been calculated and discussed, in addition the effects of cable deflection and linkage pulley are taken into account to obtain a precise stiffness calculation, and also the predetermined preload related to friction is studied through numerical example, as well as the numerical results have been compared with the experimental results. © (2011) Trans Tech Publications, Switzerland. Source

Bi J.,Northeastern University China | Zhu Z.,Northeastern University China | Yuan H.,Northeastern University China | Fan Y.,Tsinghua University | Tie M.,Beijing Institute of Nearspace Vehicles System Engineering
Proceedings - 2011 IEEE 9th International Conference on Web Services, ICWS 2011 | Year: 2011

In the process of web service composition, the check and prevention of semantic incompatibility is one of the most important issues. In this paper, a controlled Petri net (CtlPN)-based model for web service composition is proposed. Meanwhile, the optimal controller is constructed, such that the appropriate vectors of controllable place and arc are appended in the key transition which can lead to deadlock states. In addition, for the semantic incompatibility case, a policy based on appending optimal controller is presented. It is proved that our policy can be a good solution. Finally, the proposed controller is transformed as the activity of BPEL. © 2010 IEEE. Source

Wang M.,Peking University | Yang J.,Peking University | Qin G.,Peking University | Yan Y.,Beijing Institute of Nearspace Vehicles System Engineering
Proceedings of the American Control Conference | Year: 2013

This paper proposes a novel adaptive fault tolerant control strategy for flight systems which have no sufficient actuator redundancy after severe actuator failures. In addition to distributing the control signals to the remaining actuators based on the effectiveness of actuators, this strategy utilizes model reference adaptive control (MRAC) to compensate for the tracking error caused by severe failures. Furthermore, an improved weighting algorithm and an anti-saturation controller are developed to compensate for the saturation error. Finally, a simulation of the satellite launch vehicle is conducted to demonstrate the effectiveness of the proposed strategy. Compared to the traditional fault tolerant control with control allocation method, the proposed strategy gives better performance. © 2013 AACC American Automatic Control Council. Source

Nie J.-X.,Beijing Institute of Technology | Han J.-J.,Beijing Institute of Nearspace Vehicles System Engineering | Jiao Q.-J.,Beijing Institute of Technology | Jin Z.-X.,Xian Electronic Engineering Research Institute | Zhang F.,Beijing Institute of Technology
Gaodianya Jishu/High Voltage Engineering | Year: 2010

Inductance gradient is an important parameter to influence efficiency of rail-type electromagnetic launcher (EML), which is mainly controlled by geometrical parameters of launcher structure. Considering skin effect of current distribution on rails during launching, on the basis of Biot-Savat law, an analytic expression of inductance gradient was derived for rail-type EML with rectangular bore. The effects of structure geometrical parameters on inductance gradient were investigated by numerical simulations, and compared with other formulae of inductance gradient. The results show that inductance gradient decreases by about 20% when the ratio of rail thickness to rails interval changes from 1/3 to 1 for small-bore EML. Because of fully considering the influence of rails and armature dimensions, theoretical inductance gradient formula presented accords with the fact well. Source

Nie J.,Beijing Institute of Technology | Han J.,Beijing Institute of Nearspace Vehicles System Engineering | Jiao Q.,Beijing Institute of Technology | Li J.,Beijing Institute of Technology | Qin J.,Beijing Institute of Technology
IEEE Transactions on Plasma Science | Year: 2011

The rail-type electromagnetic launcher (EML) has good development and applied prospects for military and civilian dual purpose. The inductance gradient is an important parameter to design the EML structure and evaluate the system performance. Based on the BiotSavart law and current skin-effect behavior, we derive an analytic formula to predict the EML inductance gradient, which expands Batteh's formula by introducing rail thickness w and skin depth δ. Our expression is more accurate because the geometrical parameters of both rails and armature are considered in this paper. We investigate the inductance gradient change as a function of the ratio of bore width to height s/ha, rail thickness w, and two-rail interval s. Finally, our results at different scales are compared with those of other formulas of the inductance gradient. This paper could be used directly to design and optimize the rail-type EML. © 2006 IEEE. Source

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