Research On Shared Assisted Steering Control Of Four-wheel Independent Drive Electric Vehicle

With the improvement of China’s economic conditions,the number of drivers has increased,and driving styles have also diversified,implying that road accidents due to different driving styles and driving skills of various drivers will become more frequent.In response to such problems,major auto companies and universities are competing to study driving assistance system and a series of advanced intelligent technologies.Advanced driver assistance systems,on the one hand,can well reduce the fatigue state of the driver,on the other hand,it can also ensure the maximum driving safety of the vehicle under ordinary urban conditions or highway conditions.It has become the bridge to autonomous vehicles and intelligent transportation technology,which are the most popular technologies in the auto industry.This article is mainly based on the research of model predictive control considering driver and differential assisted steering shared control.Differential steering technology is one of the current research hotspots.Differential assisted steering can directly and quickly correct the driver’s steering operation through sensors.Considering that the driver’s arm’s torque on the steering wheel is different in different states.Thus,the uncertainty of the driver’s arm impedance characteristic parameters will make the shared controller have parameter differences,so the design of the shared controller needs to consider the arm impedance characteristic parameters uncertainty.By this way,differential assisted steering control can assist the driver in different states to track the path and improve the driver’s driving safety.The following is the main content of this paper and innovation results:Firstly,a driver-vehicle-road model considering the shared control of the driver and the differential assisted steering system is established.The driver-vehicle-road model is mainly composed of the driver model and the vehicle-road model.In this paper,the interaction between the driver and the differential assisted steering system needs to be considered,so the steering system model is considered.This article does not consider the longitudinal motion,pitching motion and roll of the vehicle,and only considers the lateral and yaw motion of the vehicle when building the vehicle-road model.In order to track the path of small curvature and large curvature,a driver-vehicle-road model that shares control with a differential assisted steering system is established based on a single-point preview driver model and a two-point preview driver model,respectively.Secondly,design of shared assisted steering shared controller considering driver characteristic parameters based on Model Predictive Control.In the design of the controller,considering the differential assistance sharing control for different drivers,and the actual constraints and real-time nature need to be considered.The model predictive control method considering the constraints was selected to design the controller.Then the control algorithm is transformed into a form solved by Quadprog,and the controller design is transformed into an optimal solution form.The transformation process of the control algorithm greatly decreases the difficulty of solving the shared steering controller.At the end of this chapter,the torque distribution of the lower controller is briefly introduced.Finally,design of shared controller for driver steering and differential assisted steering considering uncertain driver characteristics.In the controller design,it is necessary to identify the mechanical impedance characteristic parameters of the driver’s arm and identify the parameters range of the mechanical impedance characteristic parameters of the arm.Considering the differential assisted shared control for the driver with uncertain state,and the actual constraints and real-time nature need to be considered,the state feedback model predictive control method was selected to design the controller.Then the algorithm design process of nominal system and error model system is deduced in detail,and the algorithm design is transformed into the optimal solution form.Finally,the feasibility of the controller is verified by simulation tests.