Design Of A Teleoperation System For Tractors With Telepresence Enhanced

It is necessary for tractor drivers to separate people and vehicles in the field operation,which is improving his working conditions,protecting his physical and mental health,and raising the operating efficiency.However,the development of mechanization and intelligentization of tractors in China is slow,and it is difficult to solve such problems as adaptability to environment and high cost in a short time.Therefore,fully autonomous agricultural vehicles have not been widely used in practice.Teleoperation technology not only realizes the separation of people and vehicles,but also guarantees human-in-the-loop.It has both advantages of the two,and has received attention from scholars in many fields at home and abroad.The four-wheeled tractors are widely used as the main carries of farmland operations under the unstructured farmland environment.In this paper,a teleoperation system with telepresence enhanced was designed and applied to a MY250 tractor.Firstly,the hardware platform of the tractor teleoperation system was built,then programs of the control system was designed,and the man-machine interactive system was designed and optimized based on the realization of the basic platform.Finally,a number of driving tests were completed.The main research contents of the paper are as follows:(1)Reconstruction of the basic platform of the teleoperation system.Through the function demand analysis of the tractor teleoperation system,the overall design scheme was determined.The system consisted of three parts:the main control platform,the slave control platform and the communication module.Based on the actual measurement parameters and installation space constraints,the electronic control transformation of the tractor was finished,the sensor system and hardware of the control system were designed,the main control platform construction and the wireless network design were completed.(2)Programming of control system.MODBUS RTU protocol was extended to formulate communication protocol of control system.PWM program was designed based on C language.The main control program was designed based on Linux multi-thread technology,and the real-time response of the tractor teleoperation system was realized through the coordinated operation of a data reading thread and a data processing thread.(3)Design and optimization of the man-machine interactive system.The man-machine interactive system was an important part of the tractor teleoperation system.This paper firstly designed a friendly user interface based on the MFC under the environment of Microsoft Visual Studio 2010.Secondly,the driving aid line of the real-time video window was designed and the optimization of commands input mode was carried out.Then the steering sense design and simulation implementation of remote operation were accomplished by using the force feedback function of the steering wheel manipulator.(4)Performance experiments.Tests were carried out to detect performances of the teleoperation system.Results showed that control commands were executed with a delay of no more than 60ms and the maximum absolute error was no more than 105.3 mm when the tractor was driven along a straight line at a speed of 3.17 km/h by the system,with a maximum RMS error of 60.1 mm.The system could realize right angle turn.When the slalom test was carried out on the teleoperated tractor,there is little difference whether the driver operated in the tractor or operated remotely.Overall,the teleoperation system provided better remote driving experiences for operators.Combining with characteristics of manipulation of tractors and farmland environments,this paper designed a teleoperation system for tractors with telepresence enhanced,which provides a certain reference for the development of the remote operation technology of agricultural machinery and has important practical significance for promoting the mechanization,automation and intellectualization of agricultural production.