Research On Omini-Vision Navigation System Of Agricultural Mobile Robot

Intelligent mobile robots or vehicles for agriculture are one effective way to achieve the automation of agriculture, they are basic mobile platforms for most tasks of agriculture production. The automated guidance technology is one that must be dissolved as the basic technology. The paper has focused on the automated guidance of the agricultural mobile robot with a set of omini-vision system, including the structure and the distance and angle calibration of the omini-vision system, image capturing and processing of the crop row environment, the row detection and extracting the navigation parameters, automatic guidance controller.Analyzing the structure and the functions of key components that composed of the omini-vision system.According the demand of the automated guidance and the character of the omini-vision system, method of interpose is using to calibration of the distance and the angle relations of object and the image point.Capturing image of crop row environment around the robot using the omini-vision system, then Gray World, a simple colour constancy algorithm has used to correct the image which was distorted caused by the illumination variation. It is necessary for the outdoor agricultural mobile robot that recognizing the essential colour of the object under variational illumination condition.Then using the normalized excess-green feature and automatic threshold choosing algorithms to segment the images of crop row into two parts,object and background. The media-filter was designed to remove the impulse points. Finally distance and angle transformation is essential for the omini-vision image to revert the line character of the crop row in the real-world space.Designed the row detection and the navigation parameters extracting algorithm.First, use the Hough transform to detect the orientation of the crop rows, then combine the initialization and current value of the digital compass to evaluate the navigation parameters——the error of angle and distance.Designed the automatic guidance controller.Comparing some useful auto-control methods find that the fuzzy control is suitable for the automatic guidance of the mobile robot for agriculture.The basic priciple of fuzzy control is introduced,then a fuzzy controller for vision-guided mobile robot’s automatic navigation system is designed and has a good performance in the simulative automatic row-following tests.