Development of a Model-Based Drive-By-Wire System for Level 4 Automated Vehicles

Eco-driving algorithms enabled by Vehicle to Everything (V2X) communications in Connected and Automated Vehicles (CAVs) can reduce energy consumption by generating energy-efficient speed trajectories. One of the key challenges from an implementation perspective is to be able to execute the desired speed or acceleration commands closely. A SAE Level 4 CAV is being developed in conjunction with eco-driving to help address this issue. A custom drive-by-wire (DBW) system was built for a Honda Clarity plug-in hybrid electric vehicle (PHEV) to enable precise actuation of accelerator, brake, and steering. Transient vehicle data collected over a variety of drive cycles was synthesized to model pedal characteristics as a function of speed and target acceleration. The developed transfer functions enabled feed-forward control of the accelerator and brake pedals with a closed-loop controller handling the rest. Low speed steering maneuvers were performed to characterize the required steering torque to maintain a steady-state steering angle at different vehicle speeds. Advanced vehicle simulation software was used to understand vehicle dynamics and wheel angle response at different speeds. The development of a model based DBW system along with implementation details and results are presented.