Model-Based Pitch Control for Distributed Drive Electric Vehicle 2019-01-0451

On the dual-motor electric vehicle, which is driven by two electric motors mounted on the front and rear axles respectively, longitudinal dynamic control and electro-dynamic braking can be achieved by controlling the torque of front and rear axle motors respectively. Suspension displacement is related to the wheel torque, thus the pitch of vehicle body can be influenced by changing the torque distribution ratio. The pitch of the body has a great influence on the vehicle comfort, which occurs mainly during acceleration and braking progress. Traditionally active suspension is adopted to control the pitch of body. Instead, in this paper an ideal torque distribution strategy is developed to limit the pitch during acceleration and braking progress. This paper first explores the relationship between the torque distribution and the body pitch through the real vehicle test, which reveals the feasibility of the vehicle comfort promotion by optimizing the torque distribution coefficient. A two-degree-of-freedom semi-vehicle model is established according to the actual vehicle parameters. Based on the vehicle model, the control system is established to minimize the pitch motion during the acceleration and braking process by means of a model predictive control technique. The control effect is verified by simulation experiments.