Development of a multi-robot tractor system for agriculture field work

•Developed a multi-robot tractor system for agriculture farm work to improve work efficiency.•Came up with three formation pattern I-pattern, V-pattern and W-pattern for the work process.•Came up with headland turn coordination method to avoid collision and to reduce turn space.•Came up with space distance to determine the safety status of robots.•Came up with efficiency calculation method to evaluate the multi-robot tractor system.

A multi-robot tractor system for conducting agriculture field work was developed in order to reduce total work time and to improve work efficiency. The robot tractors can form a spatial pattern, I-pattern, V-pattern or W-pattern, during the work process. The safety zones of each robot were defined as a circle and a rectangle. The robots can coordinate to turn to the next lands without collision or deadlock. The efficiency of the system depends on the number of robots, the spatial pattern, the setting distance between each robot, and the field length. Three simulations were carried out to determine the usefulness of the system. The simulation results showed that the efficiency range of three robots using the I-pattern is from 83.2% to 89.8% at a field length of 100 m. The efficiency range of seven robots using the W-pattern is from 59.4% to 65.8% at a field length of 100 m. However, the minimum efficiency of seven robots using the W-pattern is 84.9% at a field length of 500 m. The efficiency would be higher than 85% if the field length was larger than 500 m. Thus, the newly developed multi-robot tractor system is more effective in a large field.