Impact of Soft Errors in a Brake-by-Wire System

Paper in proceeding, 2007

This paper presents an experimental evaluation of the impact of soft errors in a brake-by-wire system for road vehicles. Our goal is to assess the risk that soft errors will cause the brake system to produce undetected dangerous outputs. To this end, we injected single bit-flips in the CPU registers and the main memory of a MPC565 microcontroller running a brake controller program. For each injected bit-flip, we recorded the outputs to the brake actuator for more than one thousand control cycles. The results show that 24% (769 of 3149) of the bit-flips injected in the CPU registers resulted in undetected erroneous outputs. Of these, 24% (188 of 769) resulted in dangerous outputs. The corresponding numbers for bit-flips injected in the main memory are 35% (985 of 2831), and 8.1% (80 of 985), respectively. Despite all injections were made into "live" registers or memory elements, 40% of the register bit-flips and 51% of the memory bit-flips had no impact at all on the output.