A Comparison of Multiple Control Strategies for Vehicle Run-Off-Road and Return

A large percentage of single-vehicle automobile crashes involve a situation called run-off-road (ROR) where the vehicle leaves the roadway and travels on the surfaces adjacent to the road. Present solutions such as roadway infrastructure modifications and vehicle safety systems have helped to mitigate some ROR events but remain limited in their approach. A complete solution must also directly address the primary factor contributing to ROR crashes, which is driver performance errors. In this paper, four vehicle safety control systems, based on sliding (SL) control, linear quadratic (LQ), state flow, and classical theories, were developed to autonomously recover a vehicle from ROR without driver intervention. The vehicle response was simulated for each controller under a variety of common road departure and return scenarios. The results showed that the LQ and SL control methodologies outperformed the other controllers in terms of overall stability. However, the LQ controller was the only design to safely recover the vehicle in all of the simulation conditions examined. On average, it performed the recovery almost 50% faster and with 40% less lateral error than the SL controller at the expense of higher yaw rates.