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Wang M.,Peking University | Yang J.,Peking University | Yan Y.,Beijing Institute of Nearspace Vehicles System Engineering | Jiang Z.,Beijing Institute of Nearspace Vehicles System Engineering
Chinese Control Conference, CCC | Year: 2013

A novel fault-tolerant control scheme is proposed in this paper, in which model reference adaptive control (MRAC) strategy is incorporated with control allocation (CA) method to cope with severe actuator failures, under the assumption that actuator redundancy is no longer available in the fault system. The CA method can redistribute the control signal to the remaining actuators based on the fault information. Besides achieving CA, MRAC can guarantee the closed-loop stability of the system, reduce performance deterioration caused by the severe failure, and track the modified reference model well. The modified reference model is utilized to compensate for the input saturation error. Simulations of a satellite launch vehicle model are given to illustrate the effectiveness of the proposed scheme. © 2013 TCCT, CAA.

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.

Wang J.,Peking University | Duan Z.,Peking University | Zhao Y.,Peking University | Qin G.,Peking University | Yan Y.,Beijing Institute of Nearspace Vehicles System Engineering
International Journal of Control | Year: 2013

In this paper, the H∞ consensus control and H2 robust control synthesised with transient performance problems are investigated for a group of autonomous agents with linear or linearised dynamics. Based on the relative information between neighbouring agents and a subset of absolute information of the agents, distributed controllers are proposed for both H ∞ and H2 cases. Compared with the existing protocols, the one presented in this article focuses on improving the transient performance of the consensus problem. By using the tools from matrix analysis and robust control theory, conditions for the existence of controllers to those problems under an undirected communication topology are provided. Then, it is shown that the H2 performance limit of uncertain systems under a distributed controller equals the minimum H∞ consensus index synthesised with transient performance of a single agent by using a state feedback controller, independent of the communication topology. Finally, a simulation example as an application in Raptor-90 helicopter is proposed to illustrate the effectiveness of the theoretical results. © 2013 Taylor & Francis.

Zhao R.,Beihang University | Yan C.,Beihang University | Li X.-L.,Chinese Academy of Sciences | Jiang H.-J.,Beijing Institute of Nearspace Vehicles System Engineering
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2013

The concept of entropy increment ratio (s̄) is proposed in this paper, based on a series of direct numerical simulations (DNS) of boundary-layer flows on plates at different Mach numbers (Ma=0.7, 2.25, 6). s̄ represents the dissipation per unit mechanical energy, and is numerically monotonic and independent of Mach number changes, so it can reliably characterize the range of boundary layers. Employing this concept, we reconstruct the length scale of Baldwin-Lomax turbulence model (BL) and bring forward BL-entropy. Flow fields of a backward-facing step at low-speeds and a cylinder with conical flare at hypersonic speeds are numerically simulated to evaluate the performance of this new model. The results from the original BL model (BL-origin) and one-equation Spalart-Allmaras model (SA) are also included to be compared with the available experimental data. The comparison shows that BL-entropy could conquer the essential deficiency of the original model, providing a more physically length scale and smoother eddy viscosity distribution.

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.

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.

Shen C.,Harbin Institute of Technology | Xia X.,Harbin Institute of Technology | Cao Z.,Beijing Institute of Nearspace Vehicles System Engineering | Yu M.,Beijing Institute of Nearspace Vehicles System Engineering
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2012

In view of the fact that the characteristic parameters of a high Mach flow field vary much faster than those of the solid field, a program of approximate numerical simulation of the semi-decomposd fluid and solid coupling is developed and compiled. The calculating error of the method is analyzed by numerical simulation, and the results show that this method can accurately simulate the fluid and solid coupling in a high speed airflow field during a long unsteady process. The process of a high speed airflow impacting the seal structure is simulated by this method and the program is proved to be feasible after a comparison of the calculated results with the related experimental test. And then the features of the airflow invading the seal structure are analyzed. The contours of the flow field temperature, pressure and velocity inside and outside the seal structure and the their variation during the course of an unsteady process are summarized. The variation of the aerodynamic heat flux of the heating board with time is analyzed. The rules of the temperature variation of the seal structure with time are investigated. Finally, the results show that the structural layout of the seal plays a decisive role in the seal structure's thermal conditions.

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.

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.

Jia Z.-W.,Nanjing University of Science and Technology | Mu Y.-Q.,Beijing Institute of Nearspace Vehicles System Engineering | Guo Z.,Nanjing University of Science and Technology
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2010

The nonlinear guidance law of ground to air missile via state-dependent Riccati equation (SDRE) technique was discussed. Firstly, the guidance model was established, and the relative kinematical equations for missile and target were set up. The guidance law was designed via SDRE technique. The controller was solved using three methods: Schur method, modified Newton method and θ-D method. Finally, the simulation results show the effectiveness of the control law based on SDRE method to the two dimensional guidance law, and the SDRE method has shown a great advantage over θ-D method with larger amount of calculation, while comparing with the traditional Schur method, the modified Newton method could largely raise the calculation precision.

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