Development of an Automatic Tree Coating Machine Based on Cooperative Functioning of Multiple Nozzles

Abstract

Background: At present, the tree whitewashing in China is mainly based on the traditional manual whitewashing method, which has the shortcomings of high labor intensity, low efficiency, excessive wastage of paint, danger to human health, and poor adaptability to the strong seasonality of tree whitewashing. Objective: To reduce the sunburn and water evaporation of trees, prevent the invasion of diseases and pests, and to enhance the disease resistance of trees, the tree trunk coating mainly uses a traditional manual method. However, this mainstream manual whitewashing approach is labor- intensive and inefficient. To resolve the issue, an automatic spraying device for tree coating based on multisprinkler cooperative operation is designed. It can meet the requirements of tree whitening and replace manual operation. To some extent, this machine can reduce labor intensity and promote the healthy growth of trees. Methods: Through literature review and field research, the technical requirements and research status of tree whitewashing have been explored. The three-dimensional Software Solidworks has been used to model the rack assembly, device moving assembly, up and down moving assembly, nozzle moving support assembly, and spraying assembly, and then the three-dimensional assembly of the whole machine has been carried out. According to the simulation optimization results, the initial three-dimensional model is modified, and then the engineering drawing is drawn through the threedimensional model for prototype processing, manufacturing, and assembly. The schematic diagram and PCB pattern of the circuit board of the electronic control system have been drawn, the program of the controller k60dn512 single chip microcomputer has been written, simulation and debugging have been conducted, and the control system has been designed. Laboratory and field tests on the prototype have been conducted, and the device has been improved according to the test data. Results: Experiments show that the device can accurately spray trees with a trunk circumference of 50-125cm. When the trunk circumference is greater than 125 cm, repeated spraying can meet the spraying requirements. The trunk circumference is in the range of 50-80 cm, and the opening and closing angle is in the range of 80-100°. The spraying effect is good, and the average spraying coverage can reach 97.73%. The trunk perimeter is in the range of 80-125 cm, and the opening and closing angle is in the range of 100-120°. The spraying effect is the best, and the average spraying coverage can reach 98.06%. During the experiment, the spraying efficiency of the device can reach 100 trees/hour, which is significantly higher than the efficiency of manual operation. Conclusion: The device improves the efficiency and quality of tree spraying, reduces the labor intensity of operation, and realizes the high-efficiency spraying for tree coating.