Research on Control Strategy of Hierarchical Architecture Based on Drive-by-Wire Chassis 2023-01-0819

The rapid development of city traffic makes the driving conditions faced by vehicles increasingly complex. The drive-by-wire chassis vehicle has the characteristics of four-wheel independent steering, four-wheel independent drive and four-wheel independent braking, which has become a current research hotspot because that can meet various complex working conditions. However, it is precisely because of the high degree of controllability of the drive-by-wire chassis that the research on the control strategy has become difficult. In this paper, an integrated control strategy based on the hierarchical algorithm framework is designed for the drive-by-wire chassis vehicle, which includes a centralized control layer, a tire force distribution layer and an actuator control layer. The centralized control layer is based on the model predictive control algorithm, which takes the vehicle longitudinal speed, lateral speed and yaw rate as the control objectives, and solves the total longitudinal force, total lateral force and total yaw moment required by the vehicle. The tire force distribution layer assigns the control objectives to the four wheels, which adopts the optimal control method to transform the tire force distribution problem into a quadratic programming problem, and solves the problem with the tire utilization efficiency as the optimization objective to obtain the longitudinal force and lateral force of each wheel. The actuator control layer obtains the wheel angle and driving torque through the tire inverse model. The performance with the proposed strategy is demonstrated by steering wheel angle step input simulation test under the condition of low road friction coefficient which compared with the direct yaw moment control algorithm. In order to further verify the effectiveness of the strategy under various driving conditions, a simulation test of the sine input of steering wheel angle was carried out to verify that the strategy can improve the driving stability of the vehicle under various driving conditions.