Design of the Main Controller of Rotary Steerable System Based on FreeRTOS

Rotary steerable system needs to coordinate multiple functions and modules in real-time. If a nested interrupt processing method is used, it may lead to erroneous interrupt cascades and result in unpredictable execution time and high stack requirements. This paper developed the main controller based on the FreeRTOS and provided a preemptive task scheduling mechanism that can achieve the specified operation and response within a specific time. More specifically, the demand of the rotary steerable system was analyzed, and then the transplant of FreeRTOS to a DSP TMS320F28335 and task priorities assignment were introduced. Finally, the real-time performance of the main controller was tested through General Purpose Input/Output and DSP's load rates. The experiment results showed that the system achieved the required real-time performance and met the needs of the rotary steerable system.