Study on fault-tolerant technique of downhole steering system for rotary steering drilling

Downhole Control System in a modulated rotary steering drilling tool can automatically regulate the tool face angle to a particular position for controlling the bit direction. How to ensure the reliability of the system while it works in harsh environment is a key technique in this system. A degraded fault-tolerant system scheme based on multi-MCUs has been put forward according to the functional analysis of the system. Measurement and control functions, data acquisition and storage functions and communication decoding function are shared respectively by three MCUs when they are running normally. The system would be reconfigured based on task priority while they are partly fault, which make the system fault-tolerantly running. Some tests show that the redundant system design and degraded fault-tolerant system scheme are effectively.