A methodology is presented for the optimization of a tribological contact configuration, namely, a multi-layered elastic structure under normal (frictionless) point contact loading. This work is aimed at developing an algorithm by which the finite element (FE) mesh and the corresponding structure may be generated automatically for each variation in the vector of design variables during optimization iterations. The FE model for contact analysis may be developed in a given commercial solver such as ABAQUS or ANSYS. To do this, a flexible mesh generator, which interfaces with the FE model and the optimizer, was developed. The optimization scheme is implemented using a simulated annealing (SA) algorithm as the optimizer, with an axisymmetric (point contact) FE indentation model in the commercial finite element solver ABAQUS. The results suggest that conventional optimization methods may be employed to examine the design of tribological contact configurations such as multi-layered structures, working seamlessly within the operating system shell (e.g., Unix), and the finite element solver.

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With the development of high altitude long endurance UAV, Flight Control System in high altitude long endurance UAV must have so strong failure tolerance ability that it can improve the whole system reliability. Using redundancy technique can extremely improve failure tolerance and reliability of flight control system. Compared among civil and military aircraft and UAV, the architectures and redundancy management of fault-tolerant flight control computer (FCC)systems are introduced. Then, give a new architectures and redundancy management of fault-tolerant FCC systems for high altitude long endurance UAV. The experimental results show that the system meets the UAV's demand of high reliability, low cost and good expansibility, maximize the utilization of system resources and effectively improve the fault tolerant capability of airborne computer and the reliability of sensor subsystem. With fault injection test method, the results show that the fault tolerant methods improve fault detection rate and fault isolation rate.

With the improvement of automation and intelligence degree of unmanned aerial vehicle, its application scenarios and service scope continue to expand. The UAV system is complex and the task environment is changeable, which poses new challenges to its safety and reliability. Fault prediction and Health management (PHM) technology can effectively reduce the risk of mission interruption caused by faults, and improve the quality of UAV mission throughout its life cycle. Firstly, the framework of UAV PHM technology is proposed based on the basic concepts of UAV and PHM technology, and then the research status of UAV fault diagnosis and fault prediction technology is analyzed and summarized. Finally, the challenges of UAV fault diagnosis and prediction technology are discussed. In addition, the development trend of UAV PHM technology is summarized from four aspects: failure mechanism basis, condition monitoring technology, fault model construction and intelligent technology application, aiming to provide certain reference for the research and development of the new generation of UAV PHM technology.

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