Research On The System Of Path Planning And Assisted Navigation For The Tractor

Medium and small-sized agricultural machinery and equipment still make up a majority of ones used in Henan province and even the Central Plains region,that adapts to its features of cropland area,so the multiple operating unit consisting of medium and small-sized tractor and implement has been used widely.When the operating unit is working,whether the tractor’s running track meets the specification requirements for farming directly affects the operation quality and efficiency of agricultural production.The system of path planing and assisted navigation for tractor discussed in this paper is based on the research object to adapt to the current characteristics of agricultural production in Henan area and improve the level of information technology in field operation process,and has been pursued research around the two main projects,including the method of working path planning and tractors’ navigation driving.The software system with corresponding functions has been designed and developed,and field experiments have also been conducted.The research of this paper mainly includes the following aspects:(1)According to the kinematics model of the tractor,it’s abstracted as a rigid body,and its locating datum point and body reference system are determined,so the method has been acquired to calculate the tractors’ minimum turning radius and space.The earth fixed coordinate system is established to express the tractor’s position and attitude information using coordinate parameters and then the method of calculation of using the attitude data to compensate the position data and eliminating error calculation method of installation of the attitude sensor system have also been analyzed.The application of Gauss projection theory and its positive calculation formula has been expounded to obtain tractor’s plane coordinates.The communication protocol’s content and message format have been analyzed to Set up communication links between RTK/ARHS device and the computer system.(2)Based on the the applicable conditions and characteristics of tractor’s typical turns,the mathematical model of turning path has been established to obtain the calculation method of the headland area width and time-cost required for turning path.Using farmland boundary shape and self-defined mode to determine the direction of operating paths has been described.The thought is put forward that full permutation algorithm is used to obtain the traversal order of operating lines,and via numerical calculation tests the rule of operating paths’ traversal sequence is summed up to make the path planning scheme consume much less.(3)The tractor working path planning and navigation system has been designed and developed using Visual Basic6.0 program codes.The functions covers key links of field operation from the acquisition of Farmland Geographic information data,tractors’ path planning to tractor auxiliary navigation driving.The serial communication between RTK/ARHS device and the computer system is established to receive and sent data according the communication protocols.The electronic map and aided navigation interface have been designed to provide the real-time position and navigation driving instructions reference information of the operating unit for the driver.(4)Field experiments were conducted to test the functions of this software system.The result of path planning experiment showed that the turning paths of the path planning scheme produced by the software than other driving modes decreased time-cost by at least 50%.Wheat and maize seeding experiments using different navigation systems showed that the maximum lateral deviation from the runing tracks using auomatic navigation system is much smaller than using assisted navigation and light-bar navigation,but the maximum lateral deviation from the operating paths using auomatic navigation system is much larger than using the other ones.