Observer-based robust cooperative formation tracking control for multiple combine harvesters

The cooperative formation tracking control is a key problem for the cooperative work of multiple agricultural machines on farmland. In view of the problem, this paper proposes an observer-based robust cooperative formation tracking control method, and the cooperative harvesting system of the combine harvester group is chosen to verify the effectiveness of the proposed method. Firstly, a second-order model is used to describe the combine harvester, and both matched and mismatched disturbances are taken into account. The disturbances are then observed using an observer with a cascade structure that combines NDO and ESO. On this basis, the observer-based robust cooperative formation tracking controller is designed based on multiple agent theory and the SMC method. In addition, the APF method is also employed to achieve the goal of preventing collisions among combine harvesters or between the combine harvesters and obstacles during the collaborative harvesting process. The results demonstrate that the observer-based robust tracking control method proposed in this paper can successfully achieve the cooperative formation tracking control of the combine harvester group without a collision. Moreover, the disturbance compensation method reduces the tracking errors of the combine harvester’s working trajectory and increases the robustness of the cooperative formation harvesting system.