This work focuses on the use of load sensors to help with spraying tasks using unmanned aerial vehicles (UAVs). The study details the construction of a prototype for load measurement to validate the proof of concept. To simulate the application of agricultural pesticides, the UAV follows a predefined route and an image processing system detects the presence of diseased plants. After detection, the UAV pauses its route momentarily and activates the spraying device. The payload sensor monitors the fertilizer application process, which determines whether the amount of pesticide has been fully applied. If the storage tank is empty or the remaining quantity is insufficient for another operation, the system will command the UAV to return to the base station for refueling. Experimental validations were carried out in an indoor controlled environment to verify the proposal and the functionality of the in-flight payload monitoring system. Additionally, the UAV’s flight controller demonstrated robust performance, maintaining stability despite the challenges posed by liquid-load oscillations and varying payloads during the spraying process. In summary, our main contribution is a real-time payload monitoring system that monitors weight during flight to avoid over- or under-spraying. In addition, this system supports automatic refueling, detecting low levels of pesticides and directing the UAV to return to base when necessary.

This paper presents a practical validation of a heterogeneous formation of mobile robots in performing a load lifting, transportation, and delivery task. Assuming that an unmanned ground vehicle (UGV) is unable to perform a mission by itself due to the presence of an obstacle in the navigation route, an unmanned aerial vehicle (UAV) is then assigned to lift the cargo over this UGV, transport the obstacle, and deliver over another UGV. The UAV uses an electromagnetic actuator supported by a cable to pick up the load, the mass of which is 32% of that of the UAV. Experimental results demonstrate that the developed system is capable of performing cargo transport missions and can be scalable for applications such as package delivery in urban or remote areas and supply delivery in conflict or disaster zones.

Robotic transport missions serve a variety of valuable purposes within similar contexts. These include delivering packages in urban or remote areas, dispatching supplies to disaster or conflict zones, and facilitating delivery operations. In such a context, this work deals with the cooperation and control of multiple-robot systems involving heterogeneous robot formation with sensing and actuation capabilities to perform load transportation tasks. Two off-the-shelf unmanned ground vehicles (UGVs) working cooperatively with one unmanned aerial vehicle (UAV) are used to validate the proposal. The interactions between the UAV and the UGVs are not only information exchanges but also physical couplings required to cooperate in the load’s joint transportation. The existence of an obstacle between the two UGVs makes it impossible for them to meet each other. Thus, the lifting, transport, and delivery of the load from one UGV to the other are performed by a UAV with a suspended electromagnet actuator. Experiments are performed for a weight of 165 g (load + electronic board), which corresponds to up to 36% of the UAV’s mass.