Location-Aware Adaptive Vehicle Dynamics System: Brake Modulation

A Location-Aware Adaptive Vehicle Dynamics System (LAAVDS) is developed to assist the driver in maintaining vehicle handling capabilities through various driving maneuvers. An integral part of this System is an Intervention Strategy that uses a novel measure of handling capability, the Performance Margin, to assess the need to intervene. Through this strategy, the driver's commands are modulated to affect desired changes to the Performance Margin in a manner that is minimally intrusive to the driver's control authority. Real-time implementation requires the development of computationally efficient predictive vehicle models. This work develops one means to alter the future vehicle states: modulating the driver's brake commands. This control strategy must be considered in relationship to changes in the throttle commands. Three key elements of this strategy are developed in this work. An algorithm is developed to determine when to switch from a throttle-only control strategy to a braking strategy. A linearized brake model is developed to estimate the required brake modulation to affect the desired changes in longitudinal force. These predicted changes to the brake commands are used in the correction stage of the algorithm in which a full non-linear vehicle model simulates the longitudinal force response. The predictor-corrector control loop is closed by comparing the desired longitudinal force to the resulting force. The effect of brake modulation is exhibited in simulation results through a case study. Results show that the proposed approach yields a significant overall performance improvement. Future work will include an integration of brake and throttle modulation models.