Research On Fault Tolerance Technique For Eec Based On BIT

As the core of aero-engine control system, Electronic Engine Controller (EEC) is becoming more and more complicated,so reliability is much more important in the designe process. Based on Built In Test (BIT) technique, the multi-channel structure can be reconfigurized and the fault tolerance EEC can be achieved. It is an effective way to improve the reliability of EEC.In this paper, based on non similar redundance theroy, the author brings up an EEC design method with double channel redundant structure, where each channel consists of input, control and output parts. The fault of EEC is diagnosed by the combination of the general BIT technique and boundary sacn technique. The fault tolerance is realized by a specific switching control and overspeed protection channel, which takes care of the switching over between channels. Based on Fault Tree Analysis method, we did a theoretical analysis for the reliability of the EEC and compared results with current double channel EEC. Comparison shows that our EEC has a higher reliability.The switching control and overspeed protection channel has been particularly taken care of. The hardware part utilizes the structure of core board plus bottom board, where core board processor employed the FPGA for a better flexibility and reliability. The software part consists of application software of ARM hardcore, output management IP soft-core, overspeed protecting logic and boundary scanning IP soft-core, taking care of input switching, output switching, overspeed protection and boundary scanning respectively. Experiment shows that the control system is fault-tolerant reconfigurable with such design.