Real-time process without RTOS for the ISiMI100 Autonomous Underwater Vehicle

This paper presents a real-time process method without real-time operating system (RTOS) for the ISiMI100 Autonomous Underwater Vehicle (AUV). The AUV does not use any RTOS but a user-defined software timer to control the AUV by desired control frequency. The timer supports stable timing occurrence without miss because it was implemented by background thread process and system time of embedded computer. To verify our approach, we conducted experiments on Microsoft Windows 7 and Ubuntu Linux operating system. By the experimental results, the average error of timing occurrence was almost 0 when the desired control frequency is from 10 Hz to 100 Hz. The error ratio to desired frequency was 7.7 % on Windows 7 and 0.03 % on Ubuntu when the desired timer frequency is 10 Hz. Especially, the error ratio of 100 Hz frequency on Linux environment was 0.41 %. It means that the average timing error was 0.054 ms when the desired timer interval is 10 ms. These results show that our approach without RTOS is enough to control the ISiMI100 AUV by desired control frequency.