Trajectory optimization of aerial slung load release for piloted helicopters

• 作 者: Luofeng WANG Renliang CHEN Xufei YAN
• 机 构: National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics,Nanjing University of
• 出 处: 中国航空学报（英文版）
• 发表日期: 2021年2期
• 关键词: Helicopter slung load sys-tems Nonlinear equations Optimal control Pilot inputs

This study aims to provide the pilot with optimal control time histories for stabilization of a helicopter after releasing the slung load in aerial delivery missions. A model with 21 degrees of freedom (21-DOF) has been developed and validated for a helicopter slung load system. The con-trol history is generated with detailed procedure based on trajectory optimization. Effects of the objective function formulation on the results are discussed and rules are obtained to assist in the objective function determination. We conclude that the pilot should first decrease and then increase the collective control and adjust the longitudinal control to stabilize the helicopter after the in-hover slung load release. The obtained control history is reasonable and helpful for safety and efficiency improvement. Effects of path constraints and the Flight Control System (FCS) are studied. More stringent path constraints will lead to longer time spent and more controls. Stronger stiffness and weaker damping from the FCS will cause milder control histories but sharper on-axis state his-tories.