Hierarchical Control Design for a Helicopter-Payload System for Water Monitoring

The integration of helicopters with payloads for environmental monitoring applications presents a unique set of challenges. This paper proposes a hierarchical control scheme designed to address the complexities inherent in controlling a system composed of a helicopter and a payload dragged into water through a cable. The hierarchical architecture consists of multiple layers, each responsible for different aspects of control, including precise trajectory tracking, payload and helicopter control. At the higher level, a waypoints tracking controller generates reference velocities for the mid-loop. The intermediate level comprises a PID plus sliding mode control strategy tailored to ensure reference speed tracking for both the payload and the helicopter. The inner loop regulates the helicopter's attitude, maintaining its stability while moving the payload into the water. The effectiveness of the proposed hierarchical control scheme is validated through simulations. Results demonstrate waypoints tracking accuracy, thereby enabling more reliable and efficient monitoring missions in aquatic environment. By proposing a hierarchical control scheme for a helicopter-payload system, this research contributes to the advancement on the use of UAV s for environmental monitoring, introducing the use for small-scale helicopters in water quality monitoring.