Key Technology Research And System Development On Automatic Navigation Of Monitoring Terminal For Agricultural Machinery

Agricultural machinery automatic navigation technology and products has become more and more mature abroad, however, in the domestic the industrialization has not yet fully been formed about agricultural machinery automatic navigation technology. With the development of agricultural machinery automatic navigation technology, monitoring terminal technology has become an key part, which helps to better control the agricultural machinery automatic navigation system, realize real-time monitoring and manage the input and output decision-making information of the user.In this paper the key technology of agricultural machinery navigation monitoring terminal system was studied, which include field path planning, agricultural machinery steering automatic calibration, interfacial design, data communication and finally developed an agricultural machinery automatic navigation monitoring terminal system.(1) According to the characteristics of full coverage and global path planning of field, analyse the turning path in the edge of a field and Straight line operation path, then determine the optimization path index of the field. Field path planning algorithm were designed, which include field searching, the initial navigation operation determination, operation path planning and turning path planning.(2) A new automatic calibration method for agricultural machinery was raised, which can calculate a one-to-one relationship between steering angle of agricultural machinery and output value of angle sensor, according to the geometric relationship between the turning radius of agricultural machinery and the steering angle of agricultural machinery by GPS collecting using the position coordinated. The left and right limit of wheel angle of agricultural machinery are completing automatically using the approximation method of step by step, realize the zero calibration of the wheel angle and the calibration of the steering solenoid valve.(3) Navigation monitoring terminal system software was developed. According to the analysis of field working characteristics and the requirements, our system is based on ARM core processor, VS2008 development environment, C++ language, MFC framework and we developed automatic navigation monitoring terminal software of agricultural machinery based on Win CE. The overall function module includes man-machine interface display, RS232 serial communication, path planning, file read-write, system parameter adjustment. Data communication protocol between navigation monitoring terminal and navigation controller is established at the same time.(4) Every function module of navigation monitoring terminal system in this paper was tested and verified by installing our navigation monitoring terminal software system on tractor. Results showed that: these functions can be achieved by navigation monitoring terminal software system including animation interface display of agricultural machinery operations, serial communication, data storage, file read-write, path planning, parameter calibration etc, besides its working stable performance, even if long time to run. realizing the monitoring effectively towards the agricultural machinery navigation system. The experiment of steering automatic calibration shows that this method can realize the steering calibration of agricultural machinery quickly and accurately. The experiment of autopilot system in the fild indicates that the navigation system can implement a global path planning of land automatically and accurately,and straight line navigation Tracking Error in the 0.05 m range.