MPC-Based Downhill Coasting-Speed Control Method for Motor-Driven Vehicles 2023-01-0544

To improve the maneuverability and energy consumption of an electrical vehicle, a two-level speed control method based on model predictive control (MPC) is proposed for accurate control of the vehicle during downhill coasting. The targeted acceleration is planned using the anti-interference speed filter and MPC algorithm in the upper-level controller and executed using the integrated algorithm with the inverse vehicle dynamics and proportional-integral-derivative control model (PID) in the lower-level controller, improving the algorithm’s anti-interference performance and road adaptability. Simulations and vehicle road tests showed that the proposed method could realize accurate real-time speed control of the vehicle during downhill coasting. It can also achieve a smaller derivation between the actual and targeted speeds, as well as more stable speeds when the road resistance changes abruptly, compared with the conventional PID method. The coasting-speed overshoot of the two-level control algorithm at the initial speed of 40 km/h, 60 km/h, and 80 km/h was only 45%, 26%, and 25% of that of the PID method, respectively. In addition, the proposed method can improve the driver's speed control expectation and, simultaneously, increase the braking energy recovery and hence reduce vehicle energy consumption, compared with the control method currently used in mass-production vehicles. The regenerative braking energy of the proposed method was increased by 33%, 11%, and 8% at the initial speed of 40 km/h, 60 km/h and 80 km/h, respectively.