Optimal Trajectory Planning for Rotorcraft With Underslung Payload

Helicopters, quadcopters, and multi-rotor-copters play a crucial role in transporting supplies to remote areas worldwide, emphasizing the necessity for the development of rotorcraft systems capable of efficiently carrying heavy external loads. This paper proposes a novel approach involving a cable system that connects the rotorcraft to the payload, ensuring safe and straightforward loading and unloading operations. However, the challenge lies in piloting rotorcraft systems with underslung payloads, which are prone to payload oscillations, necessitating a careful balance between safety and efficiency. This paper focuses on devising optimal trajectory planning strategies applicable to rotorcraft systems of varying sizes with underslung payloads. A dynamic model will be developed and validated for rotorcrafts equipped with underslung payload systems. An optimal trajectory problem specific to this configuration will be addressed through analysis based on Pontryagin’s Principle, utilizing the DIDO optimal control toolbox to solve two distinct cases of optimal trajectories. The solutions will be verified and validated by optimality and feasibility checks. The findings will highlight the operational characteristics and advantages of each case, demonstrating the trade-offs between operational speed, oscillation magnitude, and vibration frequency. By adjusting the weighting coefficient in the cost function, a hybrid approach combining the strengths of both cases can be achieved.