Research On Steering Auxiliary Control Of The Lower Limb Disabled Electric Vehicle

Research on the lower limb disabled electric vehicle has been conducted based on the background that there is a strong demand for disabled people to drive a lower limb disabled electric vehicle.Considering that hub motor is used in lower limb disabled electric vehicle to achieve double rear wheel drive,steering auxiliary control strategy,in which torque can be individually assigned,for lower limb disabled electric vehicle is proposed.Steering auxiliary control is achieved through reasonable distribution of double rear wheel torque.The main contents of the thesis are as follows:Firstly,the overall structure of the lower limb disabled electric vehicle has been designed.Considering the special characteristics of drivers with lower limb disabilities,this thesis use a hand operated device of the electric wheelchair to assist in driving an electric vehicle.The hand operated device and the electric wheelchair controller for the lower limb disabled electric vehicle are designed.The whole design provides an advantage for disabled people to drive a lower limb disabled electric vehicle.Secondly,the mathematical model of the lower limb disabled electric vehicle is analyzed.A dynamic model of the lower limb disabled electric vehicle is established and then side slip angle of each wheel in the lower limb disabled electric vehicle is analyzed.The equation of state is obtained by simplifying the dynamic equations.A model of magic tire is established and the tire side slip characteristics are researched.At last,a wheel driving force model is established.Finally,the steering auxiliary control system of the lower limb disabled electric vehicle is designed by analyzing the influence of side slip angle and yaw rate on the lower limb disabled vehicle stability.A fuzzy controller,which controls deviation of the side slip angle and yaw rate by a given value of the speed and steering angle of the lower limb disabled electric vehicle,is designed in Matlab.The yawing moment of the lower limb disabled electric vehicle,which serves as a reference variable for torque distribution,is calculated by the fuzzy controller.The torque distribution of the two rear wheels is completed in the torque distribution controller,which makes it possible the steering auxiliary control for the lower limb disabled electric vehicle.The control scheme is simulated and verified,and the feasibility of the proposed control scheme is proved.