Enhanced Mobility through the Coordinated Control of Longitudinal-lateral-vertical Motion for Distributed Drive Vehicle

For the poor driving mobility of distributed electric vehicles on split-muddy roads, this study proposes a hierarchical longitudinal-lateral-vertical coordinated control architecture that considers vehicle dynamics and stability comprehensively, so that drive torque can be effectively utilized at the optimal slip rate. In this study, it researches on the mechanism that influences the vertical load transfer on longitudinal and lateral tire force, and adopts the active suspension adjustment method with the goal of improving the limit value of total wheel adhesion. It analyzes the wheel motion bases on tire adhesion ellipse theory, and designs the yaw moment control strategy with the goal of minimizing additional lateral torque. Then it proposes a torque distribution control strategy based on a multi-objective optimization function, establishes a unified optimization objective function which integrates tire loading rate, dynamic coefficients for tire vertical force, and additional lateral torque, which achieves the optimal control of longitudinal, lateral, and vertical tire forces considering ground adhesion constraints. Finally, the simulation results with MATLAB/Simulink and Carsim show that the coordinated control strategy increases the average speed of the vehicle by 19% and the torque by 5% on a split-muddy road with adhesion coefficients of 0.35 and 0.2, which effectively improves the speed and acceleration of the vehicle driving on a split-muddy road.