Research On Automatic Driving Control Of Tracked Transporter Based On LabVIEW

Field transportation of orchards in hilly areas is often labor-intensive,which greatly restricts the development of the agricultural economy.With the continuous increase of the planting area of fruit trees,the demand for a highly automated and intelligent transfer machinery has become more urgent.According to the requirements of field road transportation operations in hilly and mountainous orchards,this paper studied the navigation and positioning and path tracking systems of transfer vehicles,focused on the research based on Global Navigation Satellite System(GNSS)/Inertial Navigation System(INS)integrated navigation and positioning technology and tracked transfer vehicle path tracking technology,completed the construction of the transfer vehicle autonomous navigation system platform,and finally conducted field trials.The main contents of the research include:(1)Construction of platform for autonomous navigation system of transfer vehicle.Aiming at application scenarios in hilly and mountainous areas,a crawler-based intelligent agricultural machinery test platform was built,and the autonomous navigation and positioning system architecture and hardware scheme were analyzed and determined,and RTK-GNSS and INS modules were selected to form an autonomous navigation and positioning system.(2)GNSS/INS integrated navigation system for transfer vehicles.In view of the navigation characteristics of the GNSS/INS system,the indirect Kalman filter is selected as the sensor information fusion algorithm.Analyzing the output information and errors of GNSS/INS,and establish error state equations and error measurement equations based on GNSS/INS.Finally,the integrated navigation system is simulated and on-site positioning test.The test results show that the GNSS/INS integrated navigation positioning system based on indirect Kalman filtering can effectively improve the positioning accuracy of the transfer vehicle and output continuous and stable positioning information.(3)Analysis of ground mechanical characteristics of crawler transfer vehicles.According to the movement characteristics of the crawler chassis,a movement model of the transfer vehicle is established.In view of the interaction between the crawler and the ground,the pressure-sink relationship and the shear stress-shear displacement relationship during the running of the crawler transfer vehicle are analyzed.Analyze the force of the tracked transporter during its walking,establish a complete dynamic model of the tracked transporter,and provide a theoretical basis for the subsequent research on the movement control of the transporter.(4)Path tracking controller design.Design a dual closed-loop controller based on Model Predictive Control(MPC),and design a MPC controller based on the kinematics model in the outer loop to output the expected linear velocity and angular velocity of the crawler transporter;the inner loop design is based on the expanded state observer(ESO)active disturbance rejection controller to estimate and offset the internal and external disturbances of the system.Finally,the controller and the tracking model of the transfer vehicle are built on the Lab VIEW platform,and the linear and circular trajectories are tracked and simulated.The PID control is compared,with the MPC controller results show that is better than the fuzzy PID control in terms of overshoot,reaction time,or time to reach a steady state.(5)Field road test.In order to verify the actual effectiveness of the designed autonomous driving system platform.Based on the crawler-type automatic driving transfer platform,a typical hilly mountain orchard field road was selected as the test place.Car tests were carried out on cement roads and soil roads respectively.The test results showed that when driving on cement roads,the maximum lateral deviation was 0.14 m and the average absolute deviation was 0.046m;when driving on soft soil roads,the maximum lateral deviation was 0.15 m,the average absolute deviation is 0.051 m,which can effectively control the transfer vehicle to drive along the target path,and the control accuracy meets the requirements of the transfer vehicle for automatic driving on field roads.