Research And Implementation Of Servo System Performance Assessment And Reliability Analysis In Flight Control System

Servo system is one of the most important subsystems of flight control system. The flight safety of aircraft is directly affected by the control performance and reliability of the servo system. In statistics, most of flight failures are caused by servo system. Servo system is consisted of servo controller and servo actuator. For the safety of servo system, control performance assessment for servo controller and reliability analysis for servo actuator is a very important work.The method of control performance assessment and reliability analysis is studied in the thesis. On the basis, software is developed with Visual C++ and Microsoft Access database which is used to assess the control performance and analyze the reliability of servo system.(1) The method of control performance assessment is studied for servo controller. Based on the minimum variance rule proposed by Harris, time series model is fitted from the routine operation data and time delay of the control loop system. The feedback-invariant form is extracted from the time serial model to calculate the ideal minimum variance. From the study, defects of model identification algorithm are overcome, and the newly modified algorithm could decrease the calculating time and track time-variant disturbance, which makes it more suitable for practical application.(2) The method of reliability analysis, fault tree analysis, is studied for servo actuator. For the NP problem existing in large-scale fault tree analysis, the reasons caused the problem is analyzed and a modular decomposition method is proposed to solve the problem, and the corresponding algorithm is completed to greatly reduce the amount of computation.(3) On the basis of above method study, software requirement is analyzed, and overall plan and function modules plan for the software is designed and achieved. The software could analyze the control performance and reliability of servo system efficiently and conveniently. Besides, the software could manage the historic data which would help designers and maintainers of servo system to work more efficiently.