Research On The Control Strategy Of Wire-controlled Brakes For Agricultural Unmanned Vehicles Based On Linear Motor

Agricultural unmanned vehicles,as intelligent agricultural equipment,consist of an upper-level planning system and a lower-level control system.The upper-level planning system is responsible for information collection,processing,and sending motion commands,while the lowerlevel control system directly controls the motion state of the agricultural unmanned vehicle.In this study,we focus on the research of the braking system for agricultural unmanned vehicles.Firstly,a directdrive linear control braking scheme with fast braking response and high control accuracy is proposed.The braking force is provided by a linear motor,and the vehicle braking force is precisely adjusted by adjusting the thrust of the linear motor.By establishing the mathematical model of the linear motor and analyzing its dynamic characteristics,a dualclosed-loop control method of braking force and displacement is designed.The braking force is estimated based on the current value and combined with a fuzzy PID control algoritm to ensure fast and accurate tracking of the target value.The position loop adopts a P-type control algorithm to enable the linear motor to quickly reach the braking endpoint,eliminate braking gaps,and establish braking pressure.Subsequently,a simulation model of the linear motor is established in Matlab/Simulink according to the characteristics of the line control braking of agricultural unmanned vehicles.The joint simulation system of Matlab/Simulink and dSPACE is utilized to test and verify the performance parameters of the linear motor.Step and ramp signals are applied to simulate emergency braking and natural braking conditions,respectively,while a sine signal is used to evaluate the tracking performance of the line control braking system in a semi-physical simulation test.Finally,a hardware and software control system based on the DSP digital processor is designed,and this control system is applied to the line control braking experiment of agricultural unmanned vehicles.The experimental results demonstrate that the controller can effectively meet the braking control requirements of agricultural unmanned vehicles.The proposed research focuses on the braking control system of agricultural unmanned vehicles and presents a novel line control braking system based on a linear motor.This research provides a new solution for braking in agricultural unmanned vehicles,which contributes to the development of agricultural unmanned vehicles in our country.