Research On Tracking Control Strategy Of Heavy Vehicle Steering System

Heavy-duty vehicles are used as long-distance passenger and cargo transportation equipment,and safety and driving comfort are highly concerned by car manufacturers and consumers.The steering system is a bridge between the driver and the vehicle.Mitigating the driver's long-distance driving fatigue and driving safety is a factor that must be considered in the commercial vehicle assisted driving system.This paper studies the design of driver-assisted steering system control strategy.This paper introduces the current research on the power steering system of major universities,car manufacturers and research institutions at home and abroad.Based on the theory of automobile dynamics and hydraulic knowledge,the mathematical model and physical model of the steering system are analyzed.The experimental conditions are insufficient,and the real vehicle experiment cannot be carried out.The simulation experiment in the virtual environment is verified.Secondly,the design and analysis of the assist characteristic curve of the heavy commercial vehicle in the case of manned driving is carried out.The design of the assist characteristic curve is the key to the steering system.The theory combined with the actual experimental data is the only way to design the assist characteristics.This paper first gives an overview of the structure and working principle of the steering system of the car,as well as an overview of the "road sense" and the requirements for "road feeling " when designing the car.The design of the assist characteristic curve is the most critical part of the steering system.Therefore,firstly,there are only three types of power-assisted characteristic curves studied at present,namely: linear type,broken line type and curved type.A linear-curve assist characteristic curve based on the steering system of the heavy-duty vehicle is designed.According to the designed special-shaped curve,the 3D MAP map is drawn in Simulink.When used for model simulation,the vehicle speed and steering torque are used as input.The current assist torque.Finally,according to the designed special-purpose curve,the three-dimensional MAP map is drawn in simulink for passing speed and steering during simulation.The torque is the input quantity,and the table looks at the current assist torque.In this paper,the control strategy and damping control strategy are mainly based on the relationship between the steering wheel angle input and the real-time vehicle speed.Then,based on the characteristics of incremental PID control,an incremental PID controller is designed to transform the mathematical model into MATLAB/Simulink.For the physical model,build a simulation model at the same time.The physical models of this paper are: the whole vehicle model is built in the TruckSim software,the parameters and simulation conditions of the simulated vehicle are provided for the model,and the hydraulic simulation model is built in the AMESim software.Finally,the respective physical models are based on joint simulation of three-party software to verify the accuracy of the model.Finally,a two-degree-of-freedom vehicle dynamics model,path preview and performance index function model for heavy commercial vehicles are established to design an MPC trajectory tracking controller.The vehicle model is based on the MPC trajectory tracking controller to obtain lateral and yaw path tracking errors and steering wheel angle inputs to achieve vehicle path tracking.