Trajectory planning and control for a multilift system based on load distribution

This paper studies a load distribution based trajectory planning and control strategy for a hierarchically-controlled multilift system. It proposes a method that simultaneously plans payload trajectory and cable forces while satisfying path and force constraints and minimizing the difference in cable forces. A direct collocation method is used to solve the formulated planning problem. Then, a neighboring feedback law is designed to equalize the cable tension load distribution during flight. Here, small perturbation is performed to linearize the system with respect to the nominal path. An LQR controller is then designed for the system to track the planned trajectory. Simulation results showed the system has a good performance even under wind gust environment. The system ended with more evenly distributed cable tension load comparing with the case without planning based on the load distribution.