Optimal Time Trajectory Generation and Tracking Control for Over-Actuated Multirotors With Large-Angle Maneuvering Capability

Abstract

This paper presents an optimal time trajectory generation method for over-actuated multirotors. Different from underactuated multi-rotors that can only track a 4-D trajectory, over-actuated multi-rotors have the ability to track a 6-D trajectory. The proposed method can generate a 3-degree of freedom(DoF) position trajectory and a 3-DoF attitude trajectory. The method is composed of two steps: first, on the basis of polynomials, position and attitude trajectories satisfying geometric constraints are generated by solving unconstrainted problem in the spatial domain. Second, attitude and position dynamics constraints are added in the temporal domain, in order to achieve large-angle maneuvers. Afterwards, optimal time allocation is achieved by solving a mapping function in the temporal domain. The mapping function describes the mapping relationship between spatial variables and temporal variables. A comparative experiment is presented to verify that time allocated to trajectory by the proposed algorithm is shorter compared to other algorithms, while a tracking controller is constructed for overactuated multirotors. The tracking controller is verified to be feasible for the experimental platform through flight experiment.