Study And Design On Automatic Navigation Control System For Agricultural Machinery Based On GPS

At present, automatic navigation technology for agricultural machinery is the frontier and hotspot in the research of the precision agriculture at home and abroad as well as an important way to intelligent agriculture in the future work.In this paper, according to the characteristics of the agricultural machinery in the agricultural work environment we combine the GPS high precise positioning sensor devices, to study agricultural machinery automatic navigation technology.The main research contents are as follows:1. Research for navigation perception system. In view of the domestic and foreign research on the machine vision, inertial navigation unit, laser navigation,GPS and other kinds of positioning sensors. Combined with the analysis of the existing experimental conditions, in this research, the high precision of GPS is chosen as the main navigation and positioning sensor.2. The design of agricultural machinery vehicle steering mechanism.According to the characteristics of the vehicle navigation, transform the vehicle steering mechanism using the selected appropriate DC motor and encoder.Simulation of PID steering control was finished. And the simulation experimentis carried out on the platform of MATLAB/SIMULINK. According to the movement characteristics of navigation of the four wheeled vehicle, on the assumption that the ground is flat, and the speed of the car is stable. The vehicle steering mechanism can be regarded as a first-order kinematics model, which model is established by MATLAB/SIMULINK software.3. The design of navigation control algorithm. As the complexity and the highly nonlinear of automatic navigation control system, fuzzy controller is designed. And on the basis of the traditional fuzzy control algorithm, some optimized algorithms are proposed. For example, we use a factor which can adjust the fuzzy control for itself. As the adaptive and self-learning function of the neural network, a fuzzy neural network control system is established. The membership function of the center value, width and weight of the last layer can be adjusted online. Thus, the control effect becomes more accurate and complete.4. Research of experiment. The sensor precision testing and calibration were performed in this test, The calibration and signal processing of the GPS device, heading sensor and velocity sensor was been conducted. Based on the autonomous research and development of agricultural machinery automatic navigation platform, the straight line tracking experiments were carried out in the flat road and field.5. The test results were analyzed, which show that the reasonable of whole system, experimental error can meet the requirements of agricultural automaticnavigation. Finally, the reasons for the impact of the test accuracy were summarized.