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The Variable Dynamic Testbed Vehicle (VDTV) is presently being developed by the National Highway Traffic Safety Administration (NHTSA). It is being designed to have a “steer-by-wire” front steering system and an independent rear steering system. These steering systems enable the VDTV to emulate the directional control characteristics of a broad range of passenger vehicles. In this study, a “model-following” control method is used to modify both the steady-state and transient lateral response characteristics of a small-size VDTV to match those of compact-size and mid-size vehicles. For two classes of steering inputs considered in this study (“pseudo-step” and “sinusoidal”), the model-following control design method allowed the VDTV to accurately and robustly track the lateral responses of the target vehicles over a range of forward speed.

This study addresses the performance of four-wheel-steering vehicles in high-speed lane change maneuvers. We first compare the recorded steering command of an experienced driver in executing a lane change maneuver with that determined via solving a suitably formulated optimization problem, and found them to be qualitatively comparable. This finding allows us to analytically compare the optimal lane change performance achievable with both two and four wheel steering vehicles. For a representative high-speed lane change maneuver, our study revealed that, in the hands of an experienced driver, the performance benefit achievable with four-wheel-steering vehicles is not significant. This conclusion is in agreement with road-test results obtained with two production four-wheel-steering vehicles. The applicability of the proposed “optimal control” approach in evaluating the performance of other driver-vehicle maneuvers is an interesting topic for future study.