Research On Planning And Control Technology For Industrial Vehicle Based On Intelligent Driving Chassis

In recent years,with the rapid development of intelligent by-wire chassis and autonomous driving technology,the innovation of Planning and Control Technology applied to different scenarios and chassis has emerged one after another.The omnidirectional mobile chassis is a new structural innovation chassis.It has integrated wheel modules,each independent wheel module integrates drive,steering and braking,driven by the hub motor,steer-by-wire system steering and braking system braking.The wheel module can make the vehicle rotate around any point of the steering center through a special structural design,and its classic steering modes include four-wheel steering,diagonal,horizontal and in-situ steering driving modes.There are different application scenarios for different steering modes,which promotes the application of driverless technology in high-freedom platforms,giving full play to the advantages of autonomous driving technology.In particular,it provides solutions to solve the problems of inflexible steering of industrial vehicles and laborious driving in the factory.Based on the national key R&D project "Multi-system Efficient Integrated Hub Motor Action Module and Vehicle Torque Vector Distribution Technology"(2021YFB2500703),this paper develops a decision-making planning and trajectory tracking algorithm suitable for multi-driving modes of Intelligent Driving chassis with high degree of freedom.The main work content of the thesis is as follows:(1)A decision planning algorithm suitable for multi-driving modes of Intelligent Driving Chassis was developed.According to the different driving modes,the path decision planning algorithm of the static obstacle avoidance function of the four-wheel steering mode and the speed planning algorithm determined by all driving modes are designed,and the waypoint information(the tracking point sent to the control module)is added to the driving mode flag.The planned speed is determined by setting the driving mode flag,and the required speed is determined according to the requirements of the center steering mode,the horizontal mode,and the end speed of 0 km/h.(2)A trajectory tracking algorithm suitable for multi-driving modes of Intelligent Driving Chassis was developed.According to the different driving modes,the horizontal and longitudinal trajectory tracking algorithms are designed for the four-wheel steering mode,in-situ steering mode and oblique driving mode.For the four-wheel steering mode trajectory tracking control algorithm,the incremental PID algorithm and LQR algorithm are designed,for the in-situ center steering mode,the heading angle tracking algorithm is designed based on the two-layer PID theory,and for the oblique mode,the fixed rotation angle control algorithm determined by the expected trajectory and the PID longitudinal speed tracking algorithm are designed.(3)The Simulink-Carsim simulation platform was built to provide fixed reference lines to the trajectory tracking algorithm of the Intelligent Driving Chassis chassis multidriving mode to switch the tracking trajectory in multiple driving modes,so as to verify the tracking accuracy and functionality.The Prescan-Simulink-Carsim joint simulation platform was built to simulate the static four-wheel steering obstacle avoidance and multidriving mode switching tracking tracking simulation of the multi-driving mode decision planning algorithm and trajectory tracking control algorithm of Intelligent Driving Chassis,so as to verify the static path decision-making and planning function of the decision planning algorithm and the multi-driving mode switching trajectory tracking.(4)Actual vehicle tests were carried out for the previous research.By debugging the positioning sensor and inertial guidance sensor,the CAN communication network with the vehicle controller is completed.After adapting the test vehicle to the sensor,the trajectory tracking control algorithm of the vehicle multi-driving mode is verified.The experimental results show that the vehicle completes the tracking of the special trajectory by switching between multiple driving modes.