Design Of Control System For Autonomous Navigation And Row-follow Spray Robot

Pesticide is a kind of effective method to prevent plant diseases and pests.During traditional boom spraying in field,high-flow and wide-angle nozzles were wildly used to cover multiple crop rows because of lack of the method to follow the crop row in time.It caused a heavily environment pollution that much pesticide deposited to the soil between the crop rows.Meanwhile,more and more young labors in countryside moving to the city caused the lack of labors in countryside nowadays.And pesticide brought a great harm to human body when spraying artificially.So it was so significant to develop spray robot in filed.A autonomous navigation and row-follow spray robot was designed based on GPS and robot vision.The main research contents and results are as follows:(1)Four-wheel independent drive moving bench for robot was designed.It had the characteristics of high ground clearance.Four pairs of DC motor which was drove by motor driver were used for moving control and steering control.Incremental encoders were used to detect the speed and position of motors.Thus,a moving bench with precise moving speed and steering angle was finished.It solved the problem that tow-wheel steering bench was difficult to turn around at the end of field.(2)Robot navigation control system in filed was built based on DGPS and compass.Fuzzy control algorithm was designed to implement the straight line navigation of robot in field with robot lateral deviation error and the heading error as input,steering angle as the output.The tests indicated that the maximum error of robot straight line navigation is 11.32 cm.(3)Row-follow spray control system for boom sprayer was designed based on robot vision.Crop rows RGB images acquired by a CCD camera was analyzed by center line detecting algorithm which was optimized based on vertical projection.Processing time and accuracy rate were enhanced.The results showed that the modified algorithm of crop row centerline extracting cost 12.51 ms in average with calculation errors of 0.44 cm.(4)An ATMega16 controller for electric boom was designed to receive the parameters through an RS232 serial port form upper computer,and adjusted the electric boom to the left or right with movement monitoring by a displacement sensor.Experiments were conducted in the lab and field.The results showed that the modified algorithm of crop row centerline extracting cost 12.51 ms in average with calculation errors of 0.44 cm.The electric boom adjustment error was less than 0.3 cm when shifting right,and less than 0.5 when shifting left.(5)Some experiments were designed to detect the performance of the row-follow control system.The row-follow control error was less than 3.22 cm,2.86 cm and 2.51 cm under the speed of 0.26m/s,when following simulated crop rows with obliquity of 5°,10° and 15°,while less than 4.86 cm when following the rows of corn seedings with the speed of 0.24m/s and the shifting of 14.02 cm.It provided an effective solution for crop rows tracting and row-follow spraying.