Research On Skid-steering Control Strategy Of Independently Driven Unmanned Platform

The traditional steering mechanism is generally complex.The weight of the vehicle is large,and the energy efficiency is low.The application of the hub motors and the development of motor control technology bring more opportunities for the development of wheel independent drive skid-steering technology,which makes the technology develop rapidly.The research on coordinated control of wheel torque distribution,multi-mode skid-steering and steering resistance in the process of skid-steering is not perfect.In order to solve this problem,the main contents of this thesis are as follows.(1)In this thesis,the steering structures of different vehicles are briefly analyzed,including traditional wheel steering structure,articulated vehicle steering structure and tracked vehicle steering structure.This thesis introduces the domestic and foreign wheeled unmanned platforms,discusses the research status of wheeled unmanned platforms,and analyses the research status of six-wheel independent drive unmanned platforms skid-steering.(2)The basic theory of skid-steering is analyzed and discussed,including vehicle dynamics analysis,wheel kinematics analysis,skid-steering analysis under different driving modes.Finally the tire characteristics are analyzed.And a tire model is built,which lays a theoretical foundation for the build of the vehicle model.(3)A skid-steering control strategy based on unmanned platform is designed.Using hierarchical control method,the upper layer designs speed control strategy based on PID control algorithm and expected yaw torque control strategy based on skid mode control method.The lower layer designs expected yaw rate control strategy and anti-skid control strategy using fuzzy control algorithm.(4)The whole vehicle model and control system model are built,and the whole vehicle control system is simulated and verified.The rationality of the proposed control strategy is proved.Based on the simulation results,the relationship between the parameters of the whole vehicle and the external input parameters during the skid-steering process is given.The six-wheeled,four-wheeled and two-wheeled independent drive skid-steering vehicles studied in this thesis have laid a certain theoretical foundation for the follow-up study of multi-wheeled independent drive vehicle skid-steering.