| CPC B60L 15/20 (2013.01) [B60K 7/0007 (2013.01); G06N 7/02 (2013.01); B60L 2240/423 (2013.01)] | 6 Claims |
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1. A hierarchical control method for torque distribution of hub motor-driven electric vehicles, utilizing a hierarchical control system for torque distribution of hub motor-driven electric vehicles, wherein the hierarchical control system comprises: an upper torque distribution controller, a lower torque distribution controller, a wheel hub motor model, a 7-degree-of-freedom vehicle model, a fuzzy control module, a road module and a driver model; the upper torque distribution controller, the lower torque distribution controller, the wheel hub motor model and the 7-degree-of-freedom vehicle model are sequentially connected in that order, the fuzzy control module and the 7-degree-of-freedom vehicle model are individually connected to the upper torque distribution controller, the road module and the driver model are sequentially connected, the road module is connected to the fuzzy control module, and the driver model is connected to the 7-degree-of-freedom vehicle model;
wherein the upper torque distribution controller comprises a longitudinal speed control model, a motor efficiency control model, a 2-degree-of-freedom vehicle model, and a yaw moment control module;
wherein the lower torque distribution controller comprises motor efficiency map-based drive torque distribution control, a sequence quadratic programming module, tire slip rate-based drive torque distribution control and a slide mode control module;
wherein the hierarchical control method comprises following steps:
S1, inputting a path information and a vehicle speed state to the driver model to calculate to obtain a vehicle steering wheel angle δ and a desired vehicle speed V; and inputting the vehicle steering wheel angle δ and the desired vehicle speed V to the 7-degree-of-freedom vehicle model and the fuzzy control module;
S2, determining, by using a fuzzy control method, a torque distribution control strategy for the upper torque distribution controller; wherein the torque distribution control strategy is the motor efficiency map-based drive torque distribution control or the tire slip rate-based drive torque distribution control;
S3, calculating a torque, a yaw velocity and a slide-slip angle, and inputting the torque, the yaw velocity, the slide-slip angle to the lower torque distribution controller together with actual values fed back by a hub motor-driven electric vehicle;
S4, performing a torque distribution optimization, by the lower torque distribution controller through using methods of sequence quadratic programming and slide mode control; and calculating a generalized torque and distributing the generalized torque to the wheel hub motor model; and
S5, inputting a target torque to the 7-degree-of-freedom vehicle model; feedbacking, by the 7-degree-of-freedom vehicle model, a vehicle state to the upper torque distribution controller to form a closed-loop control.
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