An Architecture for a Safety-Critical Steer-by-Wire System

Abstract

A hardware and software architecture suitable for a safety-critical steer-by-wire systems is presented. The architecture supports three major failure modes and features several safety protocols and mechanisms. Failures due to component failures, software errors, and human errors are handled by the architecture and safety protocols. A test implementation using replicated communication channels, controllers, sensors, and actuators has been performed. The test implementation uses the CAN protocol, Motorola S12 microcontrollers, and Microchip MCP250XX components with a steering wheel and road wheel simulator. The focus of the paper is on the application level, using system engineering principles which incorporate a holistic approach to achieve safety at various levels.

Simulation of a steer-by-wire system using Flexray-based ECU network

“…In [9], authors propose safety embedded architecture for the development of a Steer-By-Wire system using CAN network. Their hardware architecture is very similar to our architecture and the CAN bus is duplicated to ensure a reliable system.…”

Active steering control strategy of steer-by-wire system based on variable steering ratio

“…And w fw G is defined as the gain between yaw rate r w and front wheel angle fw δ , if i is the steering ratio, then yaw rate r w can be furtherly defined as formula (3).…”

“…Steer-by-wire system [2,3,4] eliminate mechanical connections between the driver and the vehicle's front road wheels. Actuators are positioned at the front wheel of the vehicle and receive inputs from the control module through communication lines to turn the wheels accordingly.…”

Software safety requirements module for smart home actuators

“…Na primer, predložena je arhitektura podsistema za upravljanje vozilom posredstvom CAN protokola zasnovana na kontinualnom praüenju i razlikovanju katastrofalnih dogaÿaja (bez moguünosti oporavka, koji unose bezbednosni rizik) i benignih dogaÿaja (nakon kojih je moguü oporavak sistema) [1]. Neki autori predlažu heuristike za odreÿivanje bezbednosnih rizika u arhitekturi programske podrške, te mehanizme za otkrivanje šablona rizika i taktike za upravljanje tim rizicima [2].…”