| At present,intelligent driving technology has become a research hotspot in the field of vehicle engineering.Heavy-duty commercial vehicles have more stringent requirements for automatic steering systems due to greater load and more complex working conditions.The traditional mechanical hydraulic power steering system cannot realize the automatic steering function of commercial vehicles,and the electro-hydraulic composite steering system is too complicated.Therefore,in order to realize the intelligent driving function of heavy commercial vehicles,this paper takes the steering system of heavy commercial vehicles as the research object,and studies the dual-motor steering scheme and control strategy of heavy commercial vehicles.The main research contents are as follows:(1)Through in-depth study of electric power steering,a dual-motor power steering system is designed to meet the needs of heavy commercial vehicles,and the selection of steering motors is described.Through in-depth analysis of the assist characteristics and control mode of the dual-motor power steering system,a linear assist characteristic curve is constructed.A new control strategy of dual-motor power steering system is proposed,which can effectively distribute torque and realize fault-tolerant control.In Matlab/ Simulink,a dual-motor power steering system model is constructed,and simulation experiments are carried out to verify the accuracy of the model and the effectiveness of the control strategy.(2)In order to meet the power demand of the dual-motor power steering system proposed in this paper,combined with the motor design theory,the main structural parameters of the permanent magnet synchronous motor(PMSM)for power steering are preliminarily determined in Motor CAD software,and the PMSM model is established.In order to improve the comprehensive performance of the designed PMSM,the main structural parameters of PMSM are optimized based on genetic algorithm.Through the analysis of the control principle of PMSM and SVPWM method,the vector control strategy with d-axis current of 0 is determined,and the feasibility of the control strategy is verified by simulation experiments.(3)The frame structure of lane departure avoidance system is designed.Using the driver ’s manipulation of the vehicle and the related vehicle status information,the driver ’s intention can be indirectly identified.The cross-lane time is used as the basis for judging the lane departure,and the appropriate dynamic time threshold is selected to avoid premature intervention of the lane departure avoidance system.According to the driver ’s intention recognition and lane departure judgment results,the coordinated control strategy and automatic steering control strategy of the lane departure avoidance system are designed for the switching between the conventional function of the dual-motor power steering system and the lane departure avoidance function.(4)The linear two-degree-of-freedom model of the vehicle is established,and the vehicle road model is established.Based on MPC algorithm and PID control,a lane keeping control strategy based on dual-motor power steering system is designed.In order to simulate the driver ’s behavior,a driver model with near-far perspective is built,and a driver-vehicle-road model is established.By analyzing the lateral offset of the vehicle and the degree of conflict between human and machine,the weight of the driver and the lane keeping system can be adjusted according to the principle of fuzzy control,so as to realize the steering control of human-machine coordination.The feasibility and effectiveness of the human-machine cooperative control strategy are proved by the verification of Truck Sim / Simulink co-simulation.Figure [50] Table [14] Reference [116]... |
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