| Based on the characteristics that the driving wheel torque and speed can be independently and accurately controlled,the electric wheel drive car has unique advantages in space stability control,which is very in line with the future development needs of intelligent special vehicles.However,special vehicles often need to drive on harsh road conditions such as icy,muddy,and uneven unevenness.Electric wheel-driven vehicles must be able to achieve chassis coordinated dynamic stability control that suits their driving conditions.This paper takes electric wheel drive special vehicles as the research object,and takes the bad road conditions that may be encountered in actual work as external excitation.The research is carried out by building a vehicle dynamics model,designing a cooperative control strategy for different bad road conditions,simulation solutions,and real vehicle tests.,Designed to improve the spatial stability of electric wheel-driven special vehicles.The main contents of this article are:(1)Starting with the structural characteristics of the electric wheel drive car,according to the development needs of the control strategy,an 18-degree-of-freedom model of the whole vehicle is established,which mainly includes the body part,suspension part,wheel part,drive system part,Part of tire model for uneven road and driver model based on feedback adjustment.(2)In view of the typical harsh working conditions of special vehicles in the field,a collaborative control strategy was developed.For low tire-road,the principle of vehicle slippage is analyzed,and a direct-limit torque control and a low tire-road cornering cooperative controller based on sliding mode algorithm are designed.The offline control proves that the cooperative control algorithm is stable in the longitudinal and transverse direction of the vehicle The effectiveness of the performance control;for the split-μ road,the differential steering motion mechanism is analyzed,and the dual-steer control strategy is designed for the full-strength starting conditions.The off-line simulation verifies that the dual-steer control strategy can be significant when the off-road road starts Improve the dynamics and stability of the vehicle;for uneven road,the mechanism of the danger of rollover due to road surface excitation during vehicle cornering is analyzed,and a roll-yaw joint based on the optimal control algorithm and sliding mode algorithm is developed Control strategy,through offline simulation to verify the effectiveness of the developed control strategy.(3)In order to test the control effect of the designed collaborative controller on the actual vehicle,based on the electric wheel drive car developed by the research room,the real vehicle road test including the steady circle,double shift line and double steering on the split-μ road was completed.The reliability of the test vehicle and the correctness of the mechanism analysis are proved.The proposed control method can effectively improve the vehicle’s power and directional stability on the split-μ road surface.Based on the coordinated control strategy of the electric wheel drive vehicle under the bad road space stability proposed in this paper,the dynamic performance of the electric wheel drive special vehicle is greatly improved,and it also lays a theoretical foundation for the future intelligent electric vehicle chassis cooperative control. |
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