Bare-Metal Implementation of a Real-Time Distributed Control System Using CAN

Abstract

Distributed control systems consisting of several nodes connected via CAN bus are commonplace in many industrial and automotive settings. These systems often require real-time capabilities and generally utilize a real-time operating system (RTOS) in the nodes to achieve this. This thesis work explored the feasibility of developing a bare-metal implementation based on a previous RTOS implementation. Additionally, we explored any real-time performance advantages of the bare-metal implementation and if there were any compatibility issues in combining bare-metal nodes with RTOS nodes.

The thesis work was conducted on a model car with several nodes with specific functions connected via a CAN bus. A node tasked with braking was converted from using an RTOS to a bare-metal implementation. The brake node was tested through a reproducible simulated test run using two different scheduling approaches. It was found that a bare-metal implementation using interrupts produced a more predictable jitter. Faster execution times were also observed due to faster driver implementation. Finally, no issues in combining nodes with different implementations were found. In conclusion, a bare-metal implementation could be beneficial in some applications with low complexity that require a small performance improvement or less jitter.