A LOW-COST, REAL-TIME ALGORITHM FOR EMBEDDED DEVICES BASED ON FREERTOS KERNEL

Van-Khanh Nguyen

Abstract: A low-cost, real-time methodology for embedded devices based on well-known open source kernel - freeRTOS is presented in this study. The real-time algorithm designed consists of three main steps. Firstly, the algorithm is designed and evaluated by utilizing Matlab/Simulink toolboxes. Secondly, the generic embedded C code is generated by Matlab program. Finally, freeRTOS Tasks code is utilized based on C code generated to build and run on embedded targets. This real-time algorithm is demonstrated on a two-wheeled self-balancing robot which is employed a fuzzy PID self-tuning controller. The designed controller is executed on a famous ARM Cortex M4 core microcontroller STM32F407VTG. The experimental results show that algorithm designed operated well on embedded systems. The tracking position and rotation angle response are so good with low steady error (i.e. 0.01 [m] and less than 1.15 degrees, respectively) while stabilizing the two-wheeled at the upright. The real-time system designed is a low cost methodology and suitable for embedded system designers.

Keywords: Open source, RTOS, embedded system, ARM Cortex and fuzzy PID controller

DOI: https://doi.org/10.15623/ijret.2015.0411052