Development Of Transplanting Robot In Facility Agriculture Based On Machine Vision

Robots based on machine vision have been widely applied in facility agriculture. As a basilicequipment in the nursery factory, the transplanting robot plays an important role in improving thenursery efficiency. This research studied the application of machine vision to recognition and location ofplug seedlings, which are suitable to transplant decided by the characters of the area and perimeter ofleaves. Also an end-effector was designed to grasp, hold, insert, and release a plug. The movement ofthe manipulator and the end-effector was controlled by the computer and PLC. Main content and resultswere as follows:1. The research achievements in the field of facility agriculture robot and the application ofmachine vision in agriculture robot were reviewed, especially the development of the transplantingrobot, and the existing problems were put forward.2. A suitable machine vision system was set up for this research, which is composed of a grabber,a CCD camera, 6 fluorescent lamps and an industrial computer.3. A suitable experiment system was set up for this research, which is composed of four parts:machine vision system, control system, convection system and grasp system.4. The algorithm of recognition and location of tomato plug seedling based on machine visionwas developed. Through the analyses of linear transformation Of R, G and B in image shot by colorCDD, the color image was transformed to grayscale by proper color feature, and then was segmented bythreshold. The seedlings were recognized from background. Then the area of seedling leaves wasextracted using the blob analysis of each cell. The seedlings which need transplanted were recognizedand the position was recorded. The result shows the accuracy of machine vision system for the seedlingsof 50 cells was 98.7% while for the seedlings of 72 cells was 98.14%.5. The control system of transplanting robot was established. This system was composed of acomputer, a PLC, executive instrument, sensor and so on. RS-232 was used to communicate betweencomputer and PLC. Computer sends the position of seedling got from machine vision system to PLC,and then PLC sends the control information to the actuator of step motor and the electromagnetic. Themovement of the manipulator and the end-effector was controlled through the circuit and the air circuit. At last, the strategy of transplanting was analyzed, and different ways of transplanting were compared.The path was optimized based on greedy algorithm, and the total path became short.6. The end-effector was developed based on the character. The end-effector with fingeredgrasping was drove by two cylinders, and three kinds of fingers used to grasp, hold, insert, and release aplug were compared in the experiment, the result shows that the shovel fingers play the best behave, thesuccess rate is 82.5%.