Study on Unified Control of Drifting and Conventional Driving for Path Tracking

Investigating active safety motion control for automobiles not only plays a vital role in safeguarding people’s lives and property, but also provides strong support for the advancement of unmanned driving technology under extreme operating conditions. Since drifting maneuvers indicate vehicles stay controllable when tires operate at high slip levels, investigating drifting control is conducive to accomplishing active safety motion control of automobiles in extreme operating environments. This paper focuses on distributed-drive vehicles and proposes a novel unified control strategy applicable to both drifting and normal driving for path‑tracking. The effectiveness of the proposed strategy is validated through hardware‑in‑the‑loop testing. Firstly, a 3-DOF nonlinear vehicle model and a corresponding tire model were constructed to support controller design with guaranteed accuracy. Secondly, in response to the path‑tracking requirements, the desired state derivatives were formulated and, together with the system constraints, incorporated into the design of the overall objective function. Then, multi‑objective optimization based on the ILQR algorithm ensured the controller’s real‑time performance. Further, leveraging tire dynamics theory, the relationship between tire forces and slip velocity was analyzed across the full range of slip conditions.Finally, the effectiveness of the algorithm was validated by integrating the vehicle dynamics model from CarSim with a hardware‑in‑the‑loop test platform.The results indicate that the controller, with wheel speed control taken into account, demonstrates enhanced adaptability to variations in road roughness. In contrast, the control strategy that neglects wheel speed struggles to cope with changes in road undulations, thereby facing the risk of spin loss of control.